WO2025042430A2

WO2025042430A2 - Surgical impactor

Info

Publication number: WO2025042430A2
Application number: PCT/US2024/000024
Authority: WO
Inventors: Dana ALDEN
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-08-24
Filing date: 2024-08-24
Publication date: 2025-02-27
Anticipated expiration: 2026-02-24
Also published as: WO2025042430A3

Abstract

Briefly, the invention herein is an impactor that is electrically powered and adapted for use in surgery, comprising, a housing, a brushless DC motor that includes a stator with a plurality of coils and a rotor with a plurality of magnets; a motor controller, including a motor driver that delivers current to the coils of the stator so as to turn the rotor about the stator; a planetary gear train that includes an input, a sun gear, a planet gear, a ting gear, and an output; a shaft that includes a shaft section that is provided with an out-of-round cross-sectional shape; an impacting assembly that includes a driving component and a driven component wherein: (i) the driving component with a passage defined therein to provide clearance for an out-of-round rotating component and a rolling subassembly: (1) the out-of-round rotating component is attached to the rolling subassembly; (2) the out-of-round rotating component and the rolling subassembly ate rotated by the output of the gear train; (3) the rolling subassembly is provided with a plurality of axles, rollers, and forks wherein each of the rollers is pressed onto each of the axles, and each of the axles is pressed into each of the forks; (ii) the driven component includes an impacting portion and a stepped portion with an out-of-round bore defined therein: (1) the shaft section with the out-of-round cross-sectional shape extends through the out-of-round bore; (2) the stepped portion further includes a first roller beating surface, a second roller bearing surface, a crested surface, a first tamp, and a second tamp, each of which extends radially from the out-of-round bore; (3) the first ramp extends axially from the first roller bearing surface to the crested surface and the second ramp extends axially from the second roller bearing surface to the crested surface; (4) the crested surface is located between the first and second roller beating surfaces; and (iii) the roller of the rolling subassembly is rotated on the first roller bearing surface, up the first ramp to the crested surface and then rotated down the second ramp to the second roller bearing surface.

Description

SURGICAL IMPACTOR

FIELD OF THE INVENTION

[0001] This patent application relates to powered surgical impactors used in joint replacement surgery.

BACKGROUND OF THE INVENTION

[0002] Patients with osteoarthritis or with damaged joints often undergo joint arthroplasty to alleviate pain and to regain normal function in their joints. As part of the surgical procedure, the problematic joint is surgically removed, the patient’s joint is prepared for a prosthesis, and then, the artificial components of the prosthesis are fixed within the patient’s anatomy. To prepare a patient’s joint to receive artificial components, the surgeon must use a mallet to impact special instruments, such as a broach or a bone compactor, into the patient’s anatomy. Additionally, in order to achieve a press-fit between the patient’s anatomy and the artificial joint components, the surgeon typically must impact the artificial joint components.

[0003] As noted above, surgical impacting typically requites the use of a mallet. However, there are drawbacks to the use of a mallet. Because surgical impacting is a necessary aspect of joint replacement surgery, surgeons report that repeated mallet use, over an extended period of time, results in surgeon fatigue and injury. Many surgeons must undergo surgery themselves or shorten their career. Consequently, there is a strong need for a powered instrument to replace the use of a mallet and thereby reduce surgeon fatigue and injury. [0004] Additionally, it is very difficult to control with precision the velocity of a mallet at impact, and therefore, it is very difficult to control how far the mallet will drive instruments and the prosthetic components into a patient’s anatomy. Patients with osteoarthritis often present with poor bone quality that cannot withstand mallet blows that are too forceful; however, a mallet moving with too much velocity imparts an excessively forceful impact upon the patient’s anatomy thereby fracturing bone. Though prosthetic components must be implanted with precision, a mallet blow that is too heavy will drive in the prosthetic component too far while impacting that is too light will result in fixation of prosthetic component that is insufficient. Consequently, there is a need for a powered instrument that delivers an impact that is limited in stroke but of sufficient force to broach patient anatomy and fix implants.

[0005] The foregoing does not purport to be an exhaustive explication of all the disadvantages associated with prior art broaches; however, the present invention is directed to overcoming these (and other) disadvantages inherent in prior art systems. The advantages of the present invention will become readily apparent to those of ordinary skill in the art after reading the disclosure provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGURE 1 depicts a perspective view of a surgical impactor.

FIGURE 2 depicts a perspective view from one side of the surgical impactor.

FIGURE 3 depicts a perspective view of a motor, gear train, output, and impacting mechanism of the surgical impactor.

FIGURE 4 depicts a cut-away view of the motor, gear train, output, and impacting mechanism of the surgical impactor. FIGURE 5 depicts a perspective view of the motor, gear train without a ring gear, output, and impacting mechanism of the surgical impactor.

FIGURE 6 depicts a perspective view of the gear train of the surgical impactor.

FIGURE 7 depicts a perspective view of a rotor of the motor.

FIGURE 8 depicts a perspective view of a stator of the motor.

FIGURE 9 depicts a perspective view the ring gear of the gear train.

FIGURE 10 depicts a perspective view of the ring gear of the gear train.

FIGURE 11 depicts cut-away view of the impactor without the ring gear.

FIGURE 12 depicts a perspective view of a sun gear of the gear train.

FIGURE 13 depicts a side view of the sun gear of the gear train.

FIGURE 14 depicts a frontal view of the sun gear of the gear train.

FIGURE 15 depicts a side view of the sun gear of the gear train.

FIGURE 16 depicts a sectional view of the sun gear along line A-A of the sun gear shown in FIG. 15.

FIGURE 17 depicts a side view of a planet gear of the gear train.

FIGURE 18 depicts a frontal view of planet gear of the gear train.

FIGURE 19 depicts a rear view of the planet gear of the gear train.

FIGURE 20 depicts a frontal view of the surgical impactor without the housing and the ring gear.

FIGURE 21 depicts a sectional view along line A-A of the surgical impactor shown in FIG.

20.

FIGURE 22 depicts a side view of an input plate of the gear train.

FIGURE 23 depicts a view of the rotor side of the input plate.

FIGURE 24 depicts a perspective view of the input plate. FIGURE 25 depicts a view of the gear side of the input plate.

FIGURE 26 depicts a view of the carrier structure of the sun gear.

FIGURE 27 depicts a sectional view of the sun gear in FIG. 26.

FIGURE 28 depicts a perspective view of the surgical impactor without a housing or a ring gear.

FIGURE 29 depicts a perspective view of an output of the gear train.

FIGURE 30 depicts a frontal view of the output of the gear train.

FIGURE 31 depicts a side view of the output of the gear train.

FIGURE 32 depicts a sectional view along line A-A of the output of FIG. 31.

FIGURE 33 depicts a side view of the output, tubular member, driving component, driven component, and shaft section.

FIGURE 34 depicts a sectional view along line A-A of FIG. 33.

FIGURE 35 depicts a perspective view of the tubular member.

FIGURE 36 depicts a frontal view of the tubular member.

FIGURE 37 depicts a detailed view of area “A” of the tubular member shown in FIG. 36.

FIGURE 38 depicts a perspective view of the driving component.

FIGURE 39 depicts a perspective view of the driving component.

FIGURE 40 depicts a perspective view of the driving component.

FIGURE 41 depicts a perspective view of the driving component and the driven component.

FIGURE 42 depicts a perspective view of an out-of-round rotating component.

FIGURE 43 depicts a view of the first end surface of the out-of-round rotating component.

FIGURE 44 depicts a perspective view of the out-of-round rotating component.

FIGURE 45 depicts a frontal view of the surgical impactor without the housing. FIGURE 46 depicts a perspective view of a rolling subassembly.

FIGURE 47 depicts a bottom view of the rolling subassembly.

FIGURE 48 depicts a perspective view of the rolling subassembly.

FIGURE 49 depicts a side view of the rolling subassembly.

FIGURE 50 depicts a side view of a stepped portion of the driven component.

FIGURE 51 depicts a side view of the stepped portion of the driven component.

FIGURE 52 depicts a top view of the stepped portion of the driven component.

FIGURE 53 depicts a sectional view along line A-A of the stepped portion of the driven component shown in FIG. 50.

FIGURE 54 depicts a sectional view along line B-B of the stepped portion of the driven component shown in FIG. 51.

FIGURE 55 depicts a side view of the driving component, shaft section, and driven component.

FIGURE 56 depicts a sectional view along line A-A of the driving component, shaft section, and driven component shown in FIG. 55.

FIGURE 57-a depicts a side view of the shaft section and the driven component.

FIGURE 57-b depicts a sectional view along line A-A of the shaft section and the driven component shown in FIG. 57-a.

FIGURE 58 depicts a perspective view of the shaft section.

FIGURE 59 depicts a side view of the shaft section.

FIGURE 60 depicts a perspective view of the shaft section.

FIGURE 61 depicts a perspective view of the impactor without a battery.

FIGURE 62 depicts a sectional view of the housing with a ring gear pressed therein.

FIGURE 63 depicts a sectional view of the impactor. FIGURE 64 depicts a perspective view of the impactor with a battery being inserted therein.

FIGURE 65 depicts a perspective view of the impactor with a battery about to be inserted.

FIGURE 66 depicts a perspective view of a motor mounting component that includes a battery receptacle.

FIGURE 67 depicts a top view of the motor mounting component.

FIGURE 68 depicts a top view of the battery receptacle that is included with the motor mounting component.

FIGURE 69 depicts a perspective view of the motor mounting component that includes the battery receptacle.

FIGURE 70 depicts a side view of the motor mounting component that includes the battery receptacle.

FIGURE 71 depicts a sectional view along line A-A of FIG. 70.

FIGURE 72 depicts a side view of the motor mounting component that includes the battery receptacle.

FIGURE 73 depicts a sectional view along line A-A of FIG. 72.

FIGURE 74 depicts a perspective view of a cap that seals the second housing opening.

FIGURE 75 depicts a side view of the cap that seals the second housing opening.

FIGURE 76 depicts a sectional view along line A-A of FIG. 75.

FIGURE 77 depicts a perspective view of a cap that seals the first housing opening.

FIGURE 78 depicts a side view of the cap that seals the first housing opening.

FIGURE 79 depicts a sectional view along line A-A of FIG. 78.

FIGURE 80 depicts a top view of a handle.

FIGURE 81 depicts a sectional view of the handle along line A-A.

FIGURE 82 depicts a side view of partially disassembled handle. FIGURE 83 depicts a side view of a partially disassembled handle. FIGURE 84 depicts a side view of a partially disassembled handle. FIGURE 85 depicts a side view of a partially disassembled handle. FIGURE 86 depicts a top view of a partially disassembled handle. FIGURE 87 depicts a top view of a handle body.

FIGURE 88 depicts a top view of the second opening of the impactor.

SUMMARY OF THE INVENTION

The invention is defined by the claims set forth herein; however, briefly, the invention herein is an impactor that is electrically powered and adapted for use in surgery, comprising, a housing, a brushless DC motor that includes a stator with a plurality of coils and a rotor with a plurality of magnets; a motor controller, including a motor driver that delivers current to the coils of the stator so as to turn the rotor about the stator; a planetary gear train that includes an input, a sun gear, a planet gear, a ring gear, and an output; a shaft that includes a shaft section that is provided with an out-of-round cross-sectional shape; an impacting assembly that includes a driving component and a driven component wherein: (i) the driving component with a passage defined therein to provide clearance for an out-ofround rotating component and a rolling subassembly: (1) the out-of-round rotating component is attached to the rolling subassembly; (2) the out-of-round rotating component and the rolling subassembly are rotated by the output of the gear train; (3) the rolling subassembly is provided with a plurality of axles, rollers, and forks wherein each of the rollers is pressed onto each of the axles, and each of the axles is pressed into each of the forks; (ii) the driven component includes an impacting portion and a stepped portion with an out-of-round bore defined therein: (1) the shaft section with the out-of-round cross- sectional shape extends through the out-of-round bore; (2) the stepped portion further includes a first roller bearing surface, a second roller bearing surface, a crested surface, a first ramp, and a second ramp, each of which extends radially from the out-of-round bore; (3) the first ramp extends axially from the first roller bearing surface to the crested surface and the second ramp extends axially from the second roller bearing surface to the crested surface; (4) the crested surface is located between the first and second roller bearing surfaces; and (iii) the roller of the rolling subassembly is rotated on the first roller bearing surface, up the first ramp to the crested surface and then rotated down the second ramp to the second roller bearing surface.

DETAILED DESCRIPTION OF THE INVENTION

[0006] FIGS. 1 and 2 depict perspective views of an impactor 1000 constituting a preferred embodiment of the present invention. The impactor 1000 is powered by a plurality of lithium-ion battery cells, preferably arranged in series to provide between 18 and 24 volts. As FIGS. 1 and 2 show, the impactor 1000 is provided with a housing 1100 and a handle 1200. The housing 1100 and the components within the handle 1200 are fabricated from a polyether ketone polymer known as “PEEK.”

[0007] FIGS. 3 and 4 provide additional views of the impactor 1000. FIG. 4 provides an outline of the housing 1100 and the handle 1200 shown in FIG. 2. In FIGS. 3 and 5, the housing 1100 and the handle 1200 shown in FIG. 1 have been removed entirely thereby providing a perspective view of a motor 1300 (which preferably includes a stator 1310 and a rotor 1320), a gear train 2000, an output 1500, and an impacting assembly 3000. As more fully described herein, the gear train 2000 is a planetary gear train with each gear fabricated from PEEK, and further including, a sun gear 2100 with a plurality of teeth 2111, a planet gear 2200 with a plurality of teeth 2211, and a ring gear 2300 with a plurality of teeth 2311. [0008] Turning now to FIGS. 20 and 21, which provide a perspective view and a cross-sectional view along line A- A respectively, the gear train 2000 is shown without the ring gear 2300. The gear train 2000 provides the impactor 1000 with a gear reduction that increases torque. In the planetary gear train 2000 of the preferred embodiment, the ring gear 2300 is held fixed while the sun gears 2100-a, 2100-b are rotated about an impactor shaft 2500, which, like the ring gear 2300, also remains fixed in place and does not rotate.

[0009] The impactor shaft 2500 is a solid rod of titanium (or, alternatively, stainless steel) that has been ground to yield an outer cylindrical shaft surface 2510 with a diameter that is precise and suitable for the rotation of the sun gears 2100-a, 2100-b. The outer cylindrical shaft surface 2510 encircles a shaft axis 2501 radially and extends axially between a pair of opposing shaft ends 2502, 2503 (referred to as a “first” shaft end 2502 and a “second” shaft end 2503 to distinguish one end from the other).

[0010] Located at the first shaft end 2502, a shaft flange 2511 extends radially from the outer cylindrical shaft surface 2510 to register the stator 1310 of the brushless DC motor 1300. In the preferred embodiment, the shaft flange 2511 and the stator 1310 are both bolted to a motor mounting component 2520 (which is fabricated from PEEK).

Advantageously, the outer cylindrical shaft surface 2510 is provided with an axial stop or a cylindrical bushing that provides axial spacing between the stator 1310 and the rotor 1320; the axial spacing is dimensioned so that a magnet within the rotor 1320 is aligned axially with a coil in the stator 1310.

[0011] As the foregoing implies, the rotor 1320 is provided with a rotor axis 1321 and a plurality of permanent magnets 1322, 1323, 1324, 1325, 1326, 1327, 1328, 1329 (as is shown in FIG. 7); similarly, the stator 1310 is provided with a stator axis 1311 and a plurality of coils 1312, 1313, 1314, 1315, 1316, 1317 (as is shown in FIG. 8). The coils 1312-1317 are formed by winding copper wire around a plurality of punchings of electrical steel that have been laminated together to form a unitary part. The electrical steel punchings are equally spaced radially so that the coils 1312-1317 are also equally spaced radially about the stator axis 1311.

[0012] The permanent magnets 1322-1329 within the rotor 1320 are arranged radially about the rotor axis 1321 with alternating polarity. As is depicted in FIG. 7, the magnet designated “1322” neighbors the magnet designated “1323,” which neighbors the magnet designated “1324.” Thus, each of the magnets 1322-1329 is provided with a polarity that opposes the polarity of the neighboring magnets on either side.

[0013] As noted above, the shaft flange 2511 registers the stator 1310 and therefore ensures that the shaft axis 2501 and the stator axis 1311 are aligned when they are bolted to the motor mounting component 2520. The axial stop or cylindrical bushing provided on the outer cylindrical shaft surface 2510 positions the permanent magnets 1322-1329 in the stator 1320 so that the magnets 1322-1329 are arranged radially about the coils 1312-1317 in the stator 1310. As the foregoing implies, the rotor 1320 in the preferred embodiment is an external rotor that extends radially around the coils 1312-1317 of the stator 1310.

[0014] In addition to the coils 1312-1317 referred to above, the stator 1310 is provided with a hall-effect sensor; as FIG. 8 illustrates, the stator 1310 is provided with a plurality of hall-effect sensors (designated 1318-a, 1318-b, and 1318-c). The hall-effect sensors 1318-a, 1318-b, 1318-c provide the position of the magnets 1322-1329 in the rotor 1320 relative to the coils 1312-1317 in the stator 1310. As each of the magnets 1322-1329 passes each of the hall-effect sensors 1318-a, 1318-b, 1318-c, a signal is provided to a motor controller 1350.

[0015] Based on the signal from at least one of the hall-effect sensors 1318-a, 1318- b, 1318-c, the motor controller 1350 causes an electrical current to flow through at least one of the coils 1312-1317, thereby inducing a magnetic field within the stator 1310. The induced magnetic field either attracts or repels at least one of the permanent magnets 1322- 1329 in the rotor; thus, the induced magnetic field causes the rotor 1320 to rotate about the stator 1310.

[0016] In the preferred embodiment, the motor controller 1350 is a motor driver; however, in an alternative embodiment, the motor controller 1350 is a microcontroller or a microprocessor, and, in yet another alternative embodiment, the motor controller 1350 is a microcontroller or a microprocessor that is communicatively linked to a motor driver.

[0017] Because the rotor 1320 is connected to at least one sun gear 2100, when the induced magnetic field within the stator 1310 causes the rotor 1320 to rotate, the teeth 2111 of at least one sun gear 2100 rotate as well. The teeth 2111 of the rotating sun gear 2100 engage the teeth 2211 of at least one planet gear 2200, which engage the teeth 2311 of the ring gear 2300. Because the ring gear 2300 is held fixed in place, the planet gear 2200 rotates around an external diameter 2102 of the sun gear 2100 and an internal diameter 2302 of the ring gear 2300. Thus, the foregoing sun gear-planet gear combination may be thought of as a “set.”

[0018] FIGS. 9 and 10 provide perspective views of the ring gear 2300 included in the gear train 2000. As noted above, the ring gear 2300 is provided with a ring gear axis 2301, a cylindrically-shaped outer ring surface 2303, and a plurality of teeth 2311 (referred as “internal teeth” or “ring teeth”). The ring teeth 2311 are arranged about the internal diameter 2302 of the ring gear 2300 and extend radially inward towards the ting gear axis 2301. The ring teeth 2311 are configured to cooperate with the planet and sun gears 2200, 2100, as FIGS. 6 an 11 illustrate. Each tooth of the ring gear 2300 is provided with a ring gear pitch point to engage a corresponding pitch point on each tooth of the planet gear 2200 (which engages a corresponding pitch point on each tooth of the sun gear 2100).

[0019] In the preferred embodiment, gear blanks for the ring gear 2300 are manufactured by injecting PEEK into a mold; after injection molding, the blank is turned to an inner diameter suitable fot the desired tooth profile, and then, a plurality of teeth 2311 are cut on a gear shaper. For manufacturing efficiency, the ring gear 2300 is provided with an extended length so that a single ring gear 2300 engages multiple sets of sun gear-planet gear combinations; however, in alternative embodiments, a plurality of ring gears is employed, one for each set of sun gear-planet gear combinations.

[0020] Referring now to FIGS. 12, 13, and 14, a perspective view of the sun gear 2100 illustrates that the sun gear is a unitary part that is provided with an axis 2101 and a pair of ends 2103, 2104 (referred to as a “first sun gear end” and designated “2103” and a “second sun gear end” and designated “2104”). The sun gear 2100 is further provided with a gearing structure 2110 and a carrier structure 2120. The gearing structure 2110 extends axially from the first sun gear end 2103 and, as noted above, includes a plurality of teeth 2111 (referred to as “sun teeth” to distinguish the teeth of the sun gear from the teeth of other gears referred to herein). As FIG. 14 illustrates, the sun teeth 2111 extend radially from the gearing structure 2110 and are provided with a pitch point (referred to as a “sun gear” pitch point). [0021] The carrier structure 2120 is configured to carry a motor-gear component, such as the planet gear 2200 referred to above or an input plate (such as that shown in FIGS.

22, 23, 24, and 25 and designated “2400”). As FIGS. 14 and 16 illustrate, the carrier structure 2120 extends axially and radially from the gearing structure 2110 to form a flange 2121 (referred to as a “gear” flange to distinguish the flange 2121 from other flanges disclosed herein). Formed within the carrier structure 2120 is at least one opening (and preferably a plurality of openings), as is shown in FIG. 16 (which is a cross-sectional view of the sun gear 2100) and in FIG. 14 (which is a perspective view of the sun gear 2100). Each of the openings 2122, 2123, 2124, 2125 is provided with an axis (designated “2126,” “2127,” “2128,” and “2129” in FIG. 12 respectively). Additionally, each of the openings 2122-2125 is dimensioned to accept, at least in part, a planet gear, such as the planet gear 2200 shown in FIGS. 17, 18, and 19.

[0022] As FIG. 17 illustrates, the planet gear 2200 is provided with an axis 2201 (referred to as a “planet” axis to distinguish the axis 2201 from other axes disclosed herein), a pair of ends (referred to as a “first planet gear end 2203” and a “second planet gear end 2204”), and a shaft 2202 (referred to as a “planet gear shaft” to distinguish the planet gear shaft 2202 from other shafts disclosed herein). The planet gear shaft 2202 is provided with an outer cylindrical surface 2209 that is dimensioned to be press-fit axially through the internal diameter of a bearing, preferably a deep groove ball bearing, to form a planet gearbearing assembly. The outer cylindrical surface 2209 of the planet gear 2200 extends axially from the first planet gear end 2203 and terminates at a stop 2207 for the bearing.

[0023] Extending radially and axially from the stop 2207, the planet gear 2200 is provided with a plurality of external teeth 2211, as noted above and shown in FIGS. 18 and 19 (referred to as “planet” teeth to distinguish the planet teeth 2211 from other gear teeth disclosed herein). The planet teeth 2211 are provided with a pitch point (referred to as a “planet gear pitch point”) and are shaped to contact the pitch point of the sun teeth 2111.

[0024] The planet gear shaft 2202 is dimensioned to fit within each of the openings 2122 2123, 2124, 2125 formed within the carrier structure 2120 of the sun gear 2100. Each of the openings 2122-2125 is located radially from the sun gear axis 2101 so that the planet gear pitch point contacts both the sun gear pitch point and the ring gear pitch point, as FIG.

6 illustrates. In the preferred embodiment, each of the openings 2122-2125 is provided with an internal diameter (referred to as a “bearing ID” and designated “2132,” “2133,” “2134,” and “2135” in FIGS. 12 and 14). The bearing ID of each of the openings 2122-2125 is cylindrically-shaped and dimensioned so that the outer diameter of the deep groove ball bearing referred to above can be press-fit therein.

[0025] FIG. 21 shows a plurality of deep groove ball bearings (designated 2141, 2142, 2143, and 2144), at least one of which has been press-fit into one of the bearing IDs defined within each of the openings. FIG. 21 also shows each of the bearings 2141-2144 pressed onto each of the planet gear shafts 2202-a, 2202-b, 2202-c, 2202-d. To retain each of the bearings 2141-2144 within each of the bearing IDs 2132-2135, a retaining plate 2145 is fastened to the carrier structure via through-holes 2146, 2147, 2148, 2149 defined therein.

[0026] Referring now to FIG. 16, the sun gear 2100 is provided with a sun gearcavity 2160. As FIG. 16 shows, the sun gear cavity 2160 is defined within the sun gear 2100 and is provided with a wall that is cylindrical about the sun gear axis 2101. The wall (referred to hereinafter as the “first cylindrical wall” and designated “2161” in FIG. 16 is dimensioned to accept the impactor shaft 2500. In the preferred embodiment, the cavity 2160 is provided with a plurality of cylindrical walls (designated “2162” and “2163” in FIG. 16 and referred to respectively as “second” and “third” cylindrical walls in order to distinguish one wall from another).

[0027] To enable the sun gears 2100-a, 2100-b to rotate about the shaft 2500 while the shaft 2500 remains stationary, the second cylindrical wall 2162 and the third cylindrical wall 2163 are dimensioned so that a bearing can be inserted into the cavity 2160. In the preferred embodiment, deep groove ball bearings are pressed onto the impactor shaft 2500 and then each of the sun gears is pressed over the deep groove ball bearings; accordingly, bearings 2171, 2172 are shown after having been pressed onto the impactor shaft 2500 and the sun gear designated “2100-a” subsequendy pressed over the bearings 2171, 2172. Similarly, bearings 2173, 2174 are shown after haying been pressed onto the impactor shaft 2500 and after the sun gear designated “2100-b” has been subsequendy pressed over the bearings 2173, 2174. Thus, the sun gears 2100-a; 2100-b are pressed onto the impactor shaft 2500 so that the impactor shaft axis 2501 and the axis 2101 of each of the sun gears 2100-a, 2100-b are co-axial (or at least substantially co-axial).

[0028] As noted above, the carrier structure 2120 is shaped to carry a motor-gear component; as was also noted above, the motor-gear component may take a plurality of forms, including the planet gear 2200, shown in FIGS. 17, 18, and 19, as well as the input plate 2400, shown in FIGS. 22, 23, 24, and 25. The input plate 2400 is provided with a plurality of through-holes for fastening the rotor 1320 and one of the sun gears 2100-a, 2100-b. As the foregoing fastening connection implies, the input plate 2400 is located adjacent to the stator 1310, and hence is fabricated from aluminum in order to provide a heat sink for the coils 1312-1317 in the stator 1310; however, the input plate 2400, in an alternative embodiment, is fabricated from PEEK, titanium, or stainless steel. [0029] Additionally, the input plate 2400 is provided with an input axis 2401 (as is shown in FIGS. 22 and 24), a rotor side 2410 (as is shown in FIGS. 22 and 23), and a gear side 2420 (as is shown in FIGS. 22, 24, and 25). The rotor side 2410 of the input plate 2400 is provided with a first register 2411 that is shaped and dimensioned so that the rotor 1320 is centered and axially aligned when fastened to the [input plate 2400. In the preferred embodiment, the first register 2411 includes a raised surface 2412 that extends axially from the rotor side 2410 of the input plate 2400 to provide a rotor surface 2413. The rotor surface 2413 is shaped to match a registering surface on the rotor 1320, and hence, in the preferred embodiment, the rotor surface 2413 is cylindrically-shaped about the axis 2401 of the input plate 2400.

[0030] As noted above, the gear side 2420 of the input plate 2400 is provided with a second register 2422, which is shaped and dimensioned so that a gear (such as one of the sun gears 2100-a, 2100-b) and the rotor 1320 are in axial alignment when fastened together; consequently, the second register 2422 includes an aligning surface. As FIGS. 24 and 25 show, the second register 2422 is provided with a plurality of aligning surfaces 2423, 2424 (referred to as a “first” aligning surface 2423 and a “second” aligning surface 2424 to distinguish one from another). It is preferred that the aligning surfaces 2423, 2424 be frusto- conical in shape; however, in an alternative embodiment, the aligning surfaces 2423, 2424 are curved or spherically shaped. In yet another alternative embodiment, the aligning surfaces 2423, 2424 are cylindrically-shaped.

[0031] The aligning surfaces 2423, 2424 extend axially from the gear side 2420 of the input plate 2400 and terminate at an annular aligning surface 2422. Frustoconically- shaped, the first aligning surface 2423 extends radially inward, toward the input plate axis 2401, while the second aligning surface 2424 extends radially outward, away from the input plate axis 2401; thus, the first and second aligning surfaces 2423, 2424 provide the input plate 2400 with an aligning structure 2425 that tapers as it extends axially from the gear side 2420 of the input plate 2400.

[0032] It is advantageous for the gear side 2420 of the input plate 2400 and the carrier structure 2120 of the sun gear 2100 to complement one another. Thus, a circular groove 2130 is defined within the carrier structure 2120 of the sun gear 2100. The circular groove 2130 encircles the sun gear axis 2101 and includes a plurality of frustoconically- shaped surfaces (referred to as “first” and “second” frustoconical gear surfaces and designated “2133” and “2134” respectively in FIGS. 26 and 27). In the preferred embodiment, the first and second frustoconical gear surfaces 2133, 2134 terminate at an annular gear surface 2132.

[0033] The first and second frustoconical gear surfaces 2133, 2134 have a cross- sectional profile as is shown in FIG. 27. As shown therein, the first frustoconical gear surface 2133 extends axially towards the gearing structure 2110 of the sun gear 2100 and radially inward towards the sun gear axis 2101. Like the first frustoconical gear surface 2133, second frustoconical gear surface 2134 also extends axially towards the gearing structure 2110, but, unlike the first frustoconical gear surface 2133, the second frustoconical gear surface 2134 extends radially away from the sun gear axis 2101. Thus, the frustoconical gear surfaces 2133, 2134 provide the circular groove 2130 within the carrier structure 2120 with a taper as the frustoconical gear surfaces 2133, 2134 extend axially from carrier structure 2120 of the sun gear 2100 towards the gearing structure 2110.

[0034] Comparing FIGS. 22 and 25 to FIGS. 26 and 27, the aligning structure 2425 of the input plate 2400 (shown in FIGS. 22 and 25) and the circular groove 2130 of the carrier structure 2120 of the sun gear 2100 (shown in FIGS. 26 and 27) are shaped to complement one another. Thus, the aligning structure 2425 of the input plate 2400 fits within the circular groove 2130 of the sun gear 2100 and ensures that the input plate 2400 and the sun gear 2100 are axially aligned when fastened together. As noted above, the first aligning surface 2423 of the input plate’s aligning structure 2425 extends axially from the gear side 2420 of the input plate 2400 and radially inward, toward the input plate axis 2401 just as the first frustoconical gear surface 2133 extends axially away from the carrier structure 2120 towards the gearing structure 2110 and radially inward, toward the sun gear axis 2201.

[0035] In similar fashion, the second aligning surface 2424 of the input plate’s aligning structure 2425 extends axially from the gear side 2420 of the input plate 2400 and radially away from the input plate axis 2401 just as the second frustoconical gear surface 2134 extends axially away from the carrier structure 2120 towards the gearing structure 2110 and radially away from the sun gear axis 2201; thus, the aligning structure 2425 of the input plate 2400 is provided with a taper. Consequently, when the input plate 2400 is fastened to the sun gear 2100, as is shown in FIG. 21, the taper of the aligning structure 2425 draws the aligning structure 2425 of the input plate 2400 into the circular groove 2130 defined within the carrier structure 2120 of the sun gear 2100 and places the input plate 2400 and the sun gear 2100 into closer axial alignment.

[0036] As previously noted with respect to FIGS. 3, 4, 5, and 28 the impactor 1000 is provided with an output 1500. The output 1500 is fabricated from PEEK and provided with an output axis 1501 and an output structure 1510, as is shown in FIG. 29. Extending both axially and radially from the output structure 1510, an output flange 1521 is provided that functions much as the carrier structure 2120 functions on the sun gear 2100. [0037] Similar to the carrier structure 2120 of the sun gear, the output flange 1521 of the output 1500 is configured to carry a motor-gear component 2100, such as the planet gear 2200 shown in FIGS. 17, 18, and 19 or the input plate 2400 shown in FIGS. 22, 23, 24, and 25. Formed within the output flange 1521 is at least one opening (and preferably a plurality of openings) as is shown in FIGS. 29 and 30 (which are perspective views of the output 1500) and FIG. 32 (which is a cross-sectional view of the output 1500). As FIGS. 29, 30, and 32 show, the preferred embodiment is provided with a plurality of openings 1522, 1523, 1524, 1525, 1561, each of which is provided with an axis (the axes corresponding to openings 1522, 1523, 1524, 1525 are referred to as “opening” axes and designated “1526,” “1527,” “1528,” and “1529” in FIG. 30 respectively).

[0038] Each of the openings 1522, 1523, 1524, 1525 is dimensioned to accept, at least in part, a planet gear, and, more specifically, the planet gear shaft 2202 of the planet gear 2210 shown in FIGS. 17, 18, and 19. Therefore, each of the openings 1522-1525 is located radially from the output axis 1501 (shown as an “X” inside a circle in FIG. 6) so that the planet gear pitch point contacts both the sun gear pitch point and the ring gear pitch point, as FIG. 6 illustrates.

[0039] Just as each of the planet openings 2122-2125 of the sun gear 2100 is provided with an internal diameter, each of the openings 1522, 1523, 1524, 1525 of the output 1500 is also provided with an internal diameter (each of which is referred to as a “bearing ID” and designated “1532,” “1533,” “1534,” and “1535” in FIG. 32.). Each bearing ID is cylindrically-shaped and dimensioned so that a bearing can be press-fit therein. As FIG. 21 illustrates, the output 1500 is provided with a plurality of deep groove ball bearings (designated “2143” and “2144” in FIG. 21). [0040] As FIG. 32 illustrates, the output 1500 is provided with an output cavity 1560, which is shaped to accept the impactor shaft 2500. The output cavity 1560 includes a plurality of cylindrically-shaped surfaces (referred to as “first,” “second,” and “third” cylindrical surfaces and designated “1561,” “1562,” and “1563” respectively to distinguish one from the other). The first and second cylindrical surfaces 1561, 1562 are dimensioned so that bearings can be press-fit into the cavity 1560; in the preferred embodiment, deep groove ball bearings 1575, 1579 are pressed onto the impactor shaft 2500 and into the cylindrically-shaped cavity 1560 created by the cylindrical surfaces 1561, 1562.

[0041] As was noted above, it is within the scope of the present invention for the output flange 1521 to carry an input plate, such as the input plate 2400 shown in FIGS. 22, 23, 24 and 25. Accordingly, in an alternative embodiment, the output flange 1521 is shaped to complement the register 2422 of the gear side 2420 of the input plate 2400. Thus, the output flange 1521 in an alternative embodiment is provided with a circular groove that is identical to the circular groove 2130 shown in FIGS. 26 and 27. The circular groove of the alternative output 1500 encircles the output axis 1501 and includes a plurality of frustoconically-shaped surfaces that are identical to the frustoconical gear surfaces 2133, 2134 shown in FIGS. 26 and 27. Thus, the frustoconically-shaped surfaces of the output flange 1521 provide the alternative output 1500 with a taper that draws the alternative output 1500 and the input plate 2400 into closer axial alignment.

[0042] Referring now to FIGS. 29 and 30, the output 1500 of the preferred embodiment is provided with an output structure 1510 that is configured to transmit torque, and hence, the output structure 1510 is provided with an out-of-round radial profile 1580, which includes a lobe. It bears noting, however, that it is within the scope of the present invention for the out-of-round radial profile 1580 to be in the form of a gear, a spline, a shaft with a keyway, or a radial screw. As FIGS. 29 and 30 illustrate, the lobe provided with the out-of-round radial profile 1580 is an external lobe; preferably, the out-of-round radial profile 1580 includes a plurality of lobes (referred to as “first,” “second,” “third,” and “fourth” external lobes and designated “1581,” “1582,” “1583,” and “1584” respectively in FIG. 30).

[0043] Advantageously, the out-of-round radial profile 1580 is provided with a plurality of transition surfaces 1585, 1586, 1587, 1588 in addition to the external lobes 1581- 1584. Each of the transition surfaces 1585-1588 extends from at least one of the external lobes 1581-1584 in a generally orthogonal orientation relative to the axis of the output 1501. The transition surfaces 1585-1588 are provided with a generally flat shape, though a curved shape is within the scope of the present invention. The output 1500 is also provided with a plurality of holes (two of which are shown in FIG. 32 and designated “1589” and “1590”). Extending radially inward from each of the transition surfaces 1585-1588, each of the foregoing holes (including each of the holes designated “1589” and “1590” in FIG. 30) is defined within the out-of-round radial profile 1580 and is shaped to accept a fastener, preferable, a socket head cap screw. Accordingly, each of the holes is threaded; however, in an alternative embodiment, the holes defined within the transition surfaces 1581-1584 are shaped for pins and are therefore unthreaded.

[0044] Referring now to FIGS. 33 and 34, the output 1500 is provided with a tubular member 1595 and a fastener — ideally, a plurality of fasteners (designated “1597-a” and “1597-b” in FIG. 33). In the preferred embodiment, the tubular member 1595 is fabricated from PEEK and provided with four holes, each of which accepts a socket head cap screw (though only two of the four socket head cap screws are visible in the perspective view of FIG. 33). As the foregoing suggests, each of the four holes defined within the tubular member 1595 is dimensioned to accept one of the socket head cap screws referred to above. The out-of-round radial profile 1580 of the output 1500 is provided with a threaded hole for a male threaded fastener; in the preferred embodiment, the out-of-round radial profile 1580 is provided with four threaded holes, one for each of the socket head cap screws, which secure the tubular member 1595 to the out-of-round radial profile 1580 of the output 1500. In an alternative embodiment, the tubular member 1595 forms a unitary part with the out-of-round radial profile 1580 of the output 1500 (and hence, in such an alternative embodiment, there are neither holes nor fasteners).

[0045] The tubular member 1595 is provided with an outer surface 1598 that is generally cylindrical about an axis 1596 as shown in FIG. 35. Consequently, the outer surface 1598 encircles the axis 1596 and an out-of-round inner surface 1599. As its name suggests, the out-of-round-inner surface 1599 is provided with a major inner diameter 1576 and a minor inner diameter 1577, as is shown in FIG. 36.

[0046] As FIG. 36 also shows, the out-of-round inner surface 1599 is configured to transmit torque; consequendy, it is within the scope of the present invention for the out-of- round inner surface 1599 to be in the form of an internal gear, a spline sleeve, or a cylindrical surface with a keyway. Advantageously, the out-of-round inner surface 1599 is shaped according to the out-of-round profile 1580 of the output 1500. As a result, the out-of-round inner surface 1599 is shaped to accommodate at least one lobe and, preferably, a plurality of external lobes.

[0047] Though the tubular member 1595 transmits torque with one internal lobe, it is preferred that the tubular member 1595 include a plurality of internal lobes (designated “1591,” “1592,” “1593,” and “1594” in FIG. 35) to transmit torque. As FIG. 35 makes clear, each of the internal lobes 1591-1594 is provided with a curved internal surface so that the preferred embodiment is provided with a plurality of curved surfaces (which are designated “1571,” “1572,” “1573,” and “1574” in FIG. 36). Each of the curved surfaces 1571-1574 is provided with a diameter (referred to as a “lobe diameter” and designated “1578” in FIG. 36). In the preferred embodiment, the lobe diameter 1578 measures less than the minor inner diameter 1577 of the out-of-round inner surface 1599.

[0048] Referring again to FIGS. 33 and 34, the impactor 1000 is provided with an impacting assembly 3000. As both FIGS. 33 and 34 show, the impacting assembly 3000 is provided with a plurality of components and subassemblies, including a driving component 3100, a driven component 3200, and a shaft section 3300. The driving component 3100 includes a rolling subassembly 3110 and an out-of-round rotating component 3150 while the driven component 3200 includes a stepped portion 3210 and an impacting portion 3250.

[0049] Referring now to FIGS. 38, 39, 40, and 41, various perspective views of the out-of-round rotating component 3150 and the rolling subassembly 3110 are provided, and, as shown therein, the out-of-round rotating component 3150 and the rolling subassembly 3110 are shown attached to one another. Thus, torque applied to the out-of-round rotating component 3150 is transmitted to the rolling subassembly 3110. As noted above, the out- of-round rotating component 3150 is shaped according to the out-of-round inner surface 1599 of the tubular member 1595. Consequendy, the out-of-round rotating component 3150 is shaped so that torque from the output 1500 is transmitted to the rolling subassembly 3110. In the preferred embodiment, torque from the output 1500 is transmitted to the rolling subassembly 3110 via the tubular member 1595 and the out-of-round rotating component 3150. [0050] The out-of-round rotating component 3150 is shown in FIGS. 42, 43, and 44. As the aforementioned figures illustrate, the out-of-round rotating component 3150 is fabricated from PEEK and provided with an axis 3151, a first end surface 3161, a second end surface 3162, and an out-of-round radial surface 3570. The out-of-tound radial surface 3570 extends axially from the first end 3161 to the second end surface 3162. The out-of- round radial surface 3570 also extends radially from the axis 3151 to provide the out-of- round rotating component 3150 with a lobe. Though the FIGS. 42, 43, and 44 depict the out-of-round radial surface 3170 with a lobe, it is within the scope of the present invention for the out-of-round radial surface 3170 to be in the form of a gear, a spline, or a shaft with a keyway.

[0051] In the preferred embodiment, the out-of-round radial surface 3170 is shaped to provide the out-of-round rotating component 3150 with a plurality of lobes 3171, 3172, 3173, 3174. As the foregoing suggests, the out-of-round radial surface 3170 of the rotating member 3150 is dimensioned to cooperate with the out-of-round inner surface 1599 of the tubular member 1595.

[0052] As noted above, the out-of-round inner surface 1599 of the tubular member 1595 transmits torque; advantageously, the internal lobes 1591, 1592, 1593, 1594 defined within the out-of-round inner surface 1599 transmit torque to the external lobes 3171, 3172, 3173, 3174 formed on the out-of-round radial surface 3170 of the rotating component 3150. As FIG. 45 illustrates, the internal lobes 1591, 1592, 1593, 1594 of the tubular member 1595 and the external lobes 3171, 3172, 3173, 3174 of the rotating component 3150 are shaped so that the rotating component 3150 and the tubular member 1595 are maintained in axial alignment (or at least substantial axial alignment) while the tubular member 1595 transmits torque to the rotating component 3150. [0053] As a cross-sectional view of the output 1500 and impacting assembly 3000 shows (see, e.g., FIG. 34), the rolling subassembly 3110 is attached to the out-of-round rotating component 3150 via two socket head cap screws (referred to simply as “fasteners” and designated “3148” and “3149”). Accordingly, the out-of-round rotating component 3150 is provided with two threaded holes 3146, 3147 extending from the second end surface 3162 towards the first end surface 3161. The threaded holes 3146, 3147 are positioned so that the rolling subassembly 3110 is secured to the out-of-round rotating component 3150 in axial alignment (or at least substantial axial alignment).

[0054] Extending from the first end surface 3161 of the out-of-round rotating component 3150 is a cylindrical pocket 3145, which is shaped to accommodate a bearing, preferably a thrust bearing (shown in FIG. 34 and designated “3144”). The bearing 3144 maintains the position of the driving component 3100 axially within the impactor 1000 while the output 1500 transmits torque.

[0055] FIGS. 39 and 40 show the rolling subassembly 3110 in axial alignment with the out-of-round rotating component 3150. As noted above, and as shown in FIG. 39, the rolling subassembly 3110 is secured to the out-of-round rotating component 3150 via a plurality of bolts (with the bolt heads shown in FIG. 40 and designated “3148-a” and “3149- a”). As a necessary corollary to the aforementioned bolted connection between the rolling subassembly 3110 and the out-of-round rotating component 3150, a plurality of holes is defined within the rolling subassembly 3110 (hereinafter referred to as “fastening holes” and designated “3142” and “3143” in FIGS. 47 and 48). The fastening holes 3142, 3143 are dimension for threaded shanks 3148-b, 3149-b to extend through and engage the threads of the threaded holes 3146, 3147 defined within the out-of-round rotating component 3150, as is shown in FIG. 34. As FIG. 48 shows, the out-of-round rotating component 3150 is provided with a registering surface 3138 which preferably includes a register (not shown) that ensures that the rolling subassembly 3110 remains in axial alignment with the out-of- round rotating component 3150 when fastened together.

[0056] The rolling subassembly 3110 is provided with an axle structure 3130, which includes a roller and an axle, wherein the roller is cylindrically shaped and pressed onto the axle, as is shown in FIGS. 46, 47, 48, and 49. The axle structure 3130 also includes a fork, which holds in place a plurality of axles 3132, 3133. In the preferred embodiment, the axle structure 3130 is provided with a plurality of rollers (referred to as a “first” roller, designated “3134,” and a “second” roller, designated “3135”). Each of the rollers 3134, 3135 is pressed onto each of the axles 3132, 3133. As FIG. 47 illustrates, the axle structure 3130 is in the form of a plurality of forks, each of which holds in place one of the axles 3132, 3133 with one of the rollers 3134, 3135 pressed thereon.

[0057] As FIG. 47 further shows, a groove 3136 effectively provides the rolling subassembly 3110 with two “forks” for the axles 3132, 3133 and the rollers 3134, 3135. By milling or turning the groove 3136 into a solid piece of metal, ideally titanium, or an alloy, such as stainless steel, the rolling subassembly 3110 is provided with a wall through which a radial hole 3137 can be drilled or reamed, as is shown in FIG. 48. The groove 3136 is provided with a generally rectangular cross-sectional shape, which extends into the rolling subassembly 3110 both axially and radially so as to accommodate a cylindrically-shaped roller therein.

[0058] As FIG. 47 illustrates, the rolling subassembly 3110 is cylindrically-shaped (and hence provided with a diameter). Therefore, it is preferred that the groove 3136 be circular in shape with a radius (designated “R” in FIG. 47) and include a plurality of curved surfaces that extend about the axis 3131 (shown in FIG. 46). As noted above, the groove 3136 includes a generally rectangular cross-sectional shape so as to provide the axle structure 3130 with a plurality of opposing walls 3121, 3122 and 3123, 3124, as is shown in FIGS. 39 and 40. Opposing walls 3121, 3122 and 3123, 3124 are sufficiently spaced so that a roller can be fit thereinbetween and spin freely. It should be noted that, though it is preferred that the groove 3136 take the form of a circle, the groove 3136 can extend in a straight line or take the form of a square or rectangle and provide the rolling subassembly 3110 with a pair of opposing walls 3121, 3122 and 3123, 3124.

[0059] As was noted above, the registering surface 3138 of the rolling subassembly 3110 is secured to the second end surface 3162 of the out-of-round rotating component 3150 (which is itself rotated by the tubular member 1595). To ensure that the out-of-round rotating component 3150 and the rolling subassembly 3110 are in axial alignment when secured together, the second end surface 3162 is provided with a register (not shown), which is in the form of a cylindrically-shaped blind hole defined within the out-of-round rotating component 3150. The register is provided with a diameter that is dimensioned so that the diameter of the rolling subassembly 3110 can be bolted therein.

[0060] As noted above, the rolling subassembly 3110 is secured to the out-of-round rotating component 3150; because the out-of-round rotating component 3150 is rotated by the tubular member 1595, the rolling subassembly 3110 is also rotated while, at least one of the rollers 3134, 3135 bears against the stepped portion 3210 of the driven component 3200. In the preferred embodiment, all of the rollers 3134, 3135 bear against the stepped portion 3210 of the driven component 3200 while being rotated about an axis 3201 (which is shown as a “dot” within a circle in FIG. 52). Thus, the driven component 3200 is provided with a roller bearing surface, and preferably, a plurality of roller bearing surfaces 3228, 3229. [0061] As its moniket suggests, the stepped portion 3210 of the driven component 3200 is provided with a step; in the preferred embodiment, the stepped portion 3210 is provided with a plurahty of steps 3211, 3212, 3214, 3215, as is shown in FIG. 52. Advantageously, the steps 3211, 3212, 3214, 3215 are blended so as to form smoothly- contoured ramps 3216, 3217, as is shown in FIG. 50. Each of the ramps 3216, 3217 extends from one of the roller bearing surfaces 3228, 3229 at an angle 3230 and abuts a crested surface 3213. In the preferred embodiment, the angle 3230 measures 135°; in alternative embodiments, however, the angle 3230 measures between (and including) 90° and 160°.

[0062] As FIG. 52 illustrates, each of the ramps 3216, 3217 extends both radially from the axis 3201 and axially from each of the roller bearing surfaces 3228, 3229 (as noted above). In extending both axially and radially, the ramps 3216, 3217 of the preferred embodiment form a portion of a spiral about the axis 3201 much like the thread of a male threaded part. As FIG. 50 illustrates, each of the ramps 3216, 3217 slopes up from each of the roller bearing surfaces 3228, 3229 and terminates at the crested surface 3213 so as to form a set of ramps 3216, 3217.

[0063] The pitch of the ramps 3216, 3217 is dimensioned according to the outer- diameter of the driven component 3200, the diameter and width of the rollers 3134, 3135, tire desired axial stroke length of each impact generated by the impactor 1000, and the number of impacts the impactor 1000 delivers per revolution of the rotor 1320. In the preferred embodiment, it is desirable for the impactor 1000 to deliver an impact with a stroke length of 0.0625 inches and to deliver two such impacts per revolution of the motor 1300. Thus, it is preferred that the stepped portion 3210 of the driven component 3200 be provided with a plurality of roller bearing surfaces, a plurality of crested surfaces, and a plurality of sets of ramps linking the roller bearing surfaces and the crested surfaces.

[0064] FIG. 52 shows the stepped portion 3210 of the driven component 3200 provided with two sets of ramps to provide two impacts per revolution of the rotor 1320 (hereinafter referred to as a “first” set of ramps, designated “3216” and “3217,” and a “second” set of ramps, designated “3226” and “3227”). The two sets of ramps 3216, 3217 and 3226, 3227 link two roller bearing surfaces and two crested surfaces (hereinafter referred to as a “first” crested surface, designated “3213,” and a “second” crested surface, designated “3223” to distinguish one from another).

[0065] The second set of ramps 3226, 3227 includes a plurality of steps 3221, 3222, 3224, 3225, which are blended so as to form smoothly-contoured ramps 3226, 3227, much like the first set of ramps 3216, 3217 shown in FIG. 50. Similar to the first set of ramps 3216, 3217, which lead “up to” and “down from” the first crested surface 3213, the second set of ramps 3226, 3227 also lead “up to” and “down from” the second crested surface 3223. Each of the ramps 3226, 3227 in the second set extends axially and radially from one of the roller bearing surfaces 3228, 3229 to form an angle 3230, and each ramp of the second set abuts the second crested surface 3223.

[0066] The angle 3230 formed between each of the ramps 3226, 3227 and each of the roller bearing surfaces 3228, 3229 measures 135° (though in alternative embodiments, the angle 3230 measures between, and including, 90° and 160°). As noted above, each of the ramps 3226, 3227 extends radially from the axis 3201 and axially from each of the roller bearing surfaces 3228, 3229 to form a portion of a spiral about the axis 3201. It should be noted that, though it is preferred that the ramps 3226, 3227 extend from the roller bearing surfaces 3228, 3229 to the crested surfaces 3213, 3223 in a spiral, other step profiles are within the scope of the present invention (such as a straight ramp profile).

[0067] Referring again to FIG. 52, the steps 3211, 3212, 3221, 3222 (and hence the ramps 3216, 3226 and the crested surfaces 3213, 3223) are positioned at 180° from one another. Similarly, steps 3214, 3215 and 3224, 3225 (and hence the ramps 3217, 3227) are also positioned at 180° from one another. Consequently, when the rolling subassembly 3110 is rotated counterclockwise over the stepped portion 3210 of the driven component 3200, the first roller 3134 rolls over steps 3211, 3212 (and hence the first ramp 3216) to reach the first crested surface 3213, while, at the same time (or, at least substantially the same time), the second roller 3135 rolls over steps 3221, 3222 (and hence the second ramp 3226) to teach the second crested surface 3223. Thus, the rollers 3134, 3135 of the rolling subassembly 3110 deliver an impact axially that is transmitted to the impacting portion 3250 of the driven component 3200.

[0068] As noted above, it is desirable that the impactor 1000 deliver an impact with a stroke of 0.0625 inches; as was also noted above, the two sets of ramps 3216, 3217 and 3226, 3227 extend axially from the roller bearing surfaces 3228, 3229 to lead “up to” and “down from” the crested surfaces 3213, 3223. As was further noted above, the impactor 1000 constituting the presendy preferred embodiment delivers two impacts per revolution of the motor 1300 when the rollers 3134, 3135 roll up the two sets of the ramps 3216, 3217, 3226, 3227 and over the two crested surfaces 3213, 3223. Thus, to deliver an impact with a stroke of 0.0625 inches, the ramps 3216, 3217, 3226, 3227 extend axially 0.0626 inches from the roller bearing surfaces 3228, 3229 to the crested surfaces 3213, 3223. [0069] Referring now to FIGS. 53, 54, and 56, it is desirable that the stepped portion 3210 and the impacting portion 3250 of the driven component 3200 remain in axial alignment (or at least substantial axial alignment); consequently, the stepped portion 3210 and the impacting portion 3250 are each provided with a mating surface, referred to as a “stepped” mating surface 3218 (which is provided on the “stepped” portion 3210 of the driven component 3200), and an “impacting” mating surface 3219 (which is provided on the “impacting” portion 3250 of the driven component 3200). In the preferred embodiment, the impacting mating surface 3219 also functions as an inner surface 3252, as shown in FIG. 57.

[0070] The mating surfaces 3218, 3219 are dimensioned with respect to one another so as to provide a press fit, as is depicted in FIG. 56. In the preferred embodiment, the mating surfaces 3218, 3219 are cylindrically-shaped, with each of the mating surfaces 3218, 3219 provided with a diameter; the diameter of the stepped mating surface 3218 is between (and including) 0.001 and 0.005 inches less than the diameter of the impacting mating surface 3219.

[0071] Referring again to FIG. 52, the stepped portion 3210 of the driven component 3200 is provided with an out-of-round bore 3202, which is shaped to accommodate the shaft section 3300 and to prevent rotation of the stepped portion 3210. In the preferred embodiment, the out-of-round shape is in the form of a square (with rounded corners); however, in alternative embodiments, the out-of-round shape is in the form of a keyway, an oval, or a polygon, such as a hexagon or a rectangle. Thus, the stepped portion 3210 of the driven component 3200 is prevented from rotating, even as the rolling subassembly 3110 rotates and the tollers 3134, 3135 roll over the steps 3211, 3212, 3214, 3215, 3221, 3222, 3224, 3225 and the crested surfaces 3213, 3223. [0072] As FIG. 34 illustrates, the stepped portion 3210 is fastened to the impacting portion 3250 via a pin, preferably via a plurality of pins 3261, 3262 extending from an outer surface 3251 to an inner surface 3252 of the impacting portion of the driven component 3200 (as shown in FIG. 57). As the cross-sectional view of the stepped portion 3210 in FIG. 54 shows, the pins 3261, 3262 further extend through fastening holes 3263, 3264 defined within the stepped portion 3210. The fastening holes 3263, 3264 of the stepped portion 3210 extend radially from the out-of-round bore 3202 to the stepped mating surface 3218.

[0073] The pins 3261, 3262 extend through the fastening holes 3263, 3264 defined within the stepped portion 3210 and into holes 3265, 3266 defined within the impacting portion 3250 of the driven component 3200. To accommodate the pins 3261, 3262 extending from the holes 3263, 3264 in the stepped portion 3210, the holes 3265, 3266 defined within the impacting portion 3250 are shaped to extend radially from the inner surface 3252 of the impacting portion 3250, as is shown in FIGS. 57-a and 57-b. The inner surface 3252 of the impacting portion 3250 is dimensioned to accommodate the spring 3240, and, in the preferred embodiment, is generally cylindrical in shape.

[0074] The outer surface 3251 of the impacting portion 3250 is cylindrically-shaped (and therefore circular in cross-sectional shape); however, in an alternative embodiment, the outer surface 3251 is out-of-round in cross-sectional shape, such as octagonal or hexagonal in cross-sectional shape. In the preferred embodiment, the outer surface 3251 is dimensioned to provide the impacting portion 3250 with an “impacting” bearing surface 3255, which is in the form of an annular surface located at one of two ends 3256, 3257 (referred to as a “stepped” end and an “instruments” end respectively). The impacting bearing surface 3255 is located at the stepped end 3256 of the impacting portion 3250 (so- called to distinguish the stepped end 3256, which faces the “stepped” portion 3210, from the instruments end 3257, which is provided with a threaded hole 3258 for the attachment of a surgical “instrument,” such as a broach, a bone compaction tool, or other instrument).

[0075] As FIG. 57-b shows, the impacting bearing surface 3255 abuts the outer surface 3251 and the inner surface 3252 of the impacting portion 3250. As noted above, the second bearing surface 3238 of the stepped portion 3210 bears against the impacting bearing surface 3255 of the impacting portion 3250 of the driven component 3200.

[0076] Referring again to FIGS. 57-a and 57-b, the out-of-round bore 3202 extends axially through the stepped portion 3210 and is shaped to accommodate the shaft section

3300, which is provided with an out-of-round cross-sectional shape. The shaft section 3300 (shown in cross-section in FIG. 57-b) matches the radial shape of the out-of-round bore 3202 and thereby prevents torsional movement of the stepped portion 3210 (and hence torsional movement of the impacting portion 3250, which is pinned to the stepped portion 3210). Thus, as noted above, the shaft section 3300 is shaped so that the stepped portion 3210 moves axially along the length of the shaft section 3300 while the out-of-round cross- sectional shape of the shaft section 3300 prevents the stepped portion 3210 from rotating.

[0077] Referring now to FIG. 58, the shaft section 3300 is provided with an axis

3301, a bearing surface 3302, a flange 3303, a slot 3305, and an end 3304 (referred to as a “spring” end to distinguish the end with the spring 3240 from other ends disclosed herein). The slot 3305 extends through the shaft section 3300 to accommodate a pin 3267 (as FIGS. 57-b and 56 illustrate). As the foregoing indicates, the pin 3267 extends through the slot 3305 and through a hole 3268 defined within the stepped portion 3210 of the driven component 3200. The slot 3305 thus extends radially so that during operation of the impactor 1000, the pin 3267 moves axially within the slot 3305, while, at the same time, preventing torsional motion.

[0078] As can be seen in FIGS. 55 and 56, the shaft section 3300 extends through a passage 3102 defined within the driving component 3100. The passage 3102 is dimensioned to provide clearance for the driving component 3100 and hence the out-of-round rotating component 3150 and the rolling subassembly 3110, which rotate about the shaft section 3300. Thus, when the impactor 1000 is operated, the shaft section 3300 is threaded onto the shaft 2500 and does not rotate while the tubular member 1595, attached to the output 1500, rotates the driving component 3100 (and hence the out-of-round rotating component 3150 and the rolling subassembly 3110). As the rollers 3134, 3135 of the rolling subassembly 3110 roll “up” the ramps and over the crested surfaces 3213, 3223 of the stepped portion 3210 of the driven component 3200, the stepped portion 3210 is forced to move axially along the shaft section 3300 (as are the first and second bearing surfaces 3238, 3239, which are located on the outer surface of the stepped portion 3210). Because the first bearing surface 3238 of the stepped portion 3210 bears against the impacting bearing surface 3255 of the impacting portion 3250 of the driven component 3200, the impacting portion 3250 is forced to move axially.

[0079] Because the second bearing surface 3239 bears against the spring 3240, the axial motion of the stepped portion 3210 compresses the spring 3240. When the rollers 3134, 3135 rob “down” the ramps from the crested surfaces 3213, 3223 to the roEer bearing surfaces 3228, 3229, the spring 3240 exerts a force on the second bearing surface 3239 of the stepped portion 3210 thereby forcing the stepped portion 3210 to move axiahy towards the flange 3303 of the shaft section 3300. Thus, the spring 3240 positions the stepped portion 3210 axiahy on the shaft section 3300 so that the robers 3134, 3135 bear against the roher bearing surfaces 3228, 3229 and impact the steps (and hence the ramps) as the out-of-round rotating component 3150 is rotated about the shaft section 3300.

[0080] As the cross-sectional views of the shaft section 3300 and the driving and driven components 3100, 3200 in FIGS. 34 and 56 make clear, the spring 3240 bears against the second bearing surface 3239 of the stepped portion 3210 and a flange 3307 (referred to herein as a “spring” flange in order to distinguish other flanges disclosed herein). The spring flange 3307 is attached to the shaft section 3300 via a bolt 3306 and a threaded hole 3308 tapped within the shaft section 3300. Though the preferred embodiment is shown with a bolted attachment, alternative embodiments utilize a welded or bonded attachment between the shaft section 3300 and the spring flange 3307.

[0081] Referring now to FIGS. 61-65, the impactor 1000 is shown with the preferred housing 1100 and a motor mounting component 2520 that includes a battery receptacle 2530. The housing 1100 is provided with a plurality of flats 1106 and blind threaded holes 1107 defined therein for the attachment of a cylindrical handle, a housing axis 1101, a first housing end 1110 that terminates at a first housing opening 1111, and a second housing end 1120 that terminates at a second housing opening 1122. An inner housing surface 1105 extends axially within the housing 1100 from the first and second housing openings 1111, 1122. The inner housing surface 1105 is shaped and dimensioned to provide an appropriate fit between the housing 1100 and the various components and assemblies described herein.

[0082] As illustrated in FIGS 62 and 63, a first inner housing surface 1113 extends axially from the first housing opening 1111 and is dimensioned to provide a slip-fit with the outer surface 3251 of the impacting portion 3250 (i.e. allows the impacting portion 3250 to slide back and forth axially); consequently, in the preferred embodiment, the first inner housing surface 1113 is provided with a diameter that is dimensioned to be between (and including) 0.001 inches and 0.005 inches larger than the diameter of the outer surface 3251 of the impacting portion 3250.

[0083] FIG. 62 also shows a second inner housing surface 1123 extending axially from the second housing opening 1122; the second inner housing surface 1123 is dimensioned to provide a press-fit with an outer cylindrical surface 2528 located on the motor mounting component 2520 (as is depicted in FIG. 63). A third inner housing surface 1133 is located within the inner surface 1105 of the housing 1100 between the first and second inner housing surfaces 1113, 1123. The third inner housing surface 1133 extends axially within the housing 1100 and provides the impactor 1000 with a press-fit with the outer ring surface 2303 of the ring gear 2300.

[0084] In the preferred embodiment, the battery receptacle 2530 is included with the motor mounting component 2520, as FIGS. 66-71 illustrate. Located at one end (referred to as a “motor end” and designated “2522” in FIGS. 66, 69, 71, and 73), the motor mounting component 2520 is provided with a register 2524 for the stator 1310 and a plurality of through holes 2525, 2526 for mounting the stator 1310 of the motor 1300 and the shaft 2500. The register 2524 is in the form of a shallow cylindrical pocket, which aligns the axis 1301 of the motor 1300 with the axis 1101 of the housing 1100. The motor mounting component 2520 is also provided with a slot 2527 for electrical leads to extend from the stator 1310 to the motor controller 1350, which is positioned within the battery receptacle 2530. The motor mounting component 2500 is also provided with a groove (preferably a plurality of grooves 2521, 2529) for electrical wiring; advantageously, after the wiring is inserted into the grooves 2521, 2529, the grooves 2521, 2529 are filled in with silicone rubber or RTV rubber to prevent water ingress.

[0085] Located at an end opposing the motor end 2522 (referred to as the “battery end” and designated “2523”), the battery receptacle 2530 is provided with a sealing structure 2535, which is in the form of a thread (preferably a plurality of turns of a coarse thread, such as UNC 4-4). Extending from the first opening 1111, the housing 1100 is provided with a housing sealing structure 1115, which is also in the form of a thread (preferably a plurality of turns of a coarse thread such as 2 - 4 ½ UNC).

[0086] Because the preferred embodiment employs a plurality of coarse threads as sealing structures 1115, 2535 (referred to as a “first” sealing structure 1115 and a “second” sealing structure 2535 to distinguish one from another), the impactor 1000 is provided with threaded caps 1117, 2537 (shown in FIGS. 74-79). The caps 1117, 2537 seal the inner housing surface 1105 from the ingress of water, thereby enabling the impactor 1000 to be immersed in water for cleaning and subsequent sterilization. It is advantageous that the impactor 1000 include a threaded sleeve 1116 to protect the threads of the sealing structure 1115 when the impactor 1000 is being used (as is shown in FIGS. 62 and 63).

[0087] From the sealing structure 2535, a battery receptacle 2530 extends axially towards the motor end 2522. The battery receptacle 2530 is dimensioned so that a battery 2540 can be centered within the housing 1100 and slidably secured within the housing 1100, as is depicted in FIGS. 64 and 65. The battery receptacle 2530 terminates adjacent to the motor mounting component 2520 where the motor controller' 1350 is located.

Advantageously, spring-loaded pins are integrated into the motor controller 1350 and the motor controller 1350 positioned within the battery receptacle 2530 so that the battery receptacle 2530 aligns the spring-loaded pins with contacts on the battery 2540. After the battery 2540 is positioned within the housing 1100, the sealing cap 2537 (shown in FIGS. 74-76) is placed onto the sealing structure 2535 to secure the battery 2540 on the pins within the housing 1100.

[0088] To assemble the impactor 1000 within the housing 1100, the shaft 2500 is attached to the motor mounting component 2520 via a plurality of bolts extending through the holes 2526 in the motor mounting component 2520. Then, the stator 1310 is attached and registered to the motor mounting component 2520 via a plurality of bolts extending through the holes 2525 in the motor mounting component 2520. Next, the sun gears 2100- a, 2100-b with the input plate and the rotor 1320 are positioned onto the shaft 2500 so that the rotor 1320 extends radially about the stator 1310. Then, the output 1500 and the tubular member 1595 are assembled onto the shaft 2500 and the shaft section 3300 with the driving and driven components 3100, 3200 assembled thereon is torqued onto the threaded end of the shaft 2500. After the motor 1300 and the motor mounting component 2520, the shaft 2500, the gear train 2000, the output 1500, and the shaft section 3300 with the impacting assembly 3000 have been put together, the assembly is placed into the housing 1100. As noted above, the outer cylindrical surface 2528 of the motor mounting component 2520 provides is dimensioned to provide a press-fit with the second inner housing surface 1123 of the housing 1100.

[0089] Turning now to FIGS. 80-88, the impactor 1000 is provided with a handle 1200. The handle is a provided with two plates (a trigger plate and a support plate), a handle body, a trigger component, a support component, a switch, a bracket, and a cover. The trigger plate 1220 is provided with two ends (referred to as a first trigger end 1221 and a second trigger end 1222); similarly, the support plate 1230 is provided with two ends (referred to as a first support end 1231 and a second support end 1232). Like the plates 1220, 1230, the handle body 1240 is also provided with two ends (referred to as a first body end 1241 and a second body end 1242).

[0090] The plates 1220, 1230 are titanium (or, alternatively, stainless steel) and radiused to provide the handle 1200 with a cylindrical shape having a diameter that measures between 1.20 and 2.1 inches, preferably 1.5 inches. To extend the breadth of a human hand, the plates 1220, 1230 are provided with a length that is no less than 3.5 inches; in the preferred embodiment, the trigger plate 1220 measures 4.5 inches while the support plate 1230 measures 6.025 inches.

[0091] First and second support components 1261, 1262 are attached to the first and second body ends 1241, 1242 via a plurality of fasteners 1243, 1244 (as is shown in FIG. 86). First and second trigger components 1251, 1252 are attached at the trigger ends 1221, 1222 via a plurality of fasteners 1293, 1294 and a rectangular rod 1253 (as is shown in FIG.

81). Each of the trigger components 1251, 1252 is provided with a pair of grooves 1254, 1255 that slidably secure each of the trigger components 1251, 1252 to each of the handle body ends 1241, 1242.

[0092] The switch 1270 (shown on a circuit board 1272 and insulated with conformal coating) is a single-pole, single-throw, normally-open, momentary tact switch, which is housed and supported within at least one of the support components 1261, 1262. The switch 1270 has an ingress protection rating of 67 (i.e. an IP rating of 67) and is provided with an operating and storage temperature of up to 125° C. To turn on the impactor 1000, the switch 1270 must be actuated by squeezing together the trigger plate 1220 and the support plate 1230. Because each of the trigger components 1251, 1252 is slidably secured to each of the body ends 1241, 1242, the trigger component 1250 slides towards one of the support components 1261, 1262 and to at least one switch 1270 that is housed therein. As FIG. 83 illustrates, the switch 1270 is provided with sufficient travel to extend beyond the support component so that at least one of the trigger components 1251, 1252 depresses the actuator 1271 of the switch 1270 when the plates 1220, 1230 are squeezed together.

[0093] A pair of compression springs exert a force on the rectangular rod 1253 that directs the trigger component away from the actuator 1271 on the switch 1270, thereby returning the actuator 1271 to an open position, which turns the impactor 1000 off.

Consequently, the surgeon must overcome the force of the springs to close the switch 1270 and turn on the impactor 1000 and may simply release the trigger plate 1220 to turn off the impactor 1000. To maintain the orientation of the springs, the rectangular rod 1253 is provided with a plurality of pins 1256, 1257 that are axially aligned with a pair of counterbored holes 1246, 1247 defined within the handle body 1240. The springs are positioned to surround the pins 1256, 1257 while, at the same time, fitting within the counterbored holes 1246, 1247. Thus, when the trigger plate 1220 is squeezed towards the and support plate 1230 and then released, the axial orientation of the springs is maintained.

[0094] The handle 1200 is secured to the housing 1100 at the second end 1120 via a pair of brackets 1281, 1282. As FIGS. 63 and 88 show, each of the brackets 1281, 1282 is attached to the housing 1100 so that the handle 1200 extends radially from the axis 1101 of the housing 1100; thus, by gripping the handle 1200, the surgeon’s arm can be aligned with the axis 1101 so that the impactor 1000 can be positioned more accurately and the forces generated by the impactor 1000 can be borne by the surgeon’s larger arm and chest muscles rather than the surgeon’s wrist, (as is the case with a pistol grip power tool). [0095] As noted above, the handle 1200 includes a tact switch 1270 that is located within at least one of the support components 1261, 1262. To reach at least one of the switches located within the handle 1200, electrical wiring is routed from within the housing 1100, through at least one of the brackets 1281, 1282, and into at least one of the support components 1261, 1262. To prevent the ingress of water and debris into the brackets 1281, 1282, the handle 1200 includes a cover, preferably a pair of covers 1291, 1292 (one for each of the brackets 1281, 1282). To further prevent the ingress of water and debris, the plates 1220, 1230 can be overmolded with silicone rubber or neoprene.

[0096] While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

WHAT IS CLAIMED IS: Claim 1 : An impactor that is electrically powered and adapted for use in surgery, comprising, a) a housing b) brushless DC motor that includes a stator with a plurality of coils and a rotor with a plurality of magnets; c) a motor controller, including a motor driver that delivers current to the coils of the stator so as to turn the rotor about the stator; d) a planetary gear train that includes an input, a sun gear, a planet gear, a ring gear, and an output; e) a shaft that includes a shaft section that is provided with an out-of-round cross-sectional shape; f) an impacting assembly that includes a driving component and a driven component wherein: i) the driving component with a passage defined therein to provide clearance for an out-of-round rotating component and a rolling subassembly: (1) the out-of-round rotating component is attached to the rolling subassembly; (2) the out-of-round rotating component and the rolling subassembly are rotated by the output of the gear train; (3) the rolling subassembly is provided with a plurality of axles, rollers, and forks wherein each of the rollers is pressed onto each of the axles, and each of the axles is pressed into each of the forks ii) the driven component includes an impacting portion and a stepped portion with an out-of-round bore defined therein:

(1) the shaft section with the out-of-round cross-sectional shape extends through the out-of-round bore;

(2) the stepped portion further includes a first roller bearing surface, a second roller bearing surface, a crested surface, a first ramp, and a second ramp, each of which extends radially from the out-of-round bore;

(3) the first ramp extends axially from the first roller bearing surface to the crested surface and the second ramp extends axially from the second roller bearing surface to the crested surface;

(4) the crested surface is located between the first and second roller bearing surfaces; and iii) the roller of the rolling subassembly is rotated on the first roller bearing surface, up the first ramp to the crested surface and then rotated down the second ramp to the second roller bearing surface.

Claim 2: The impactor according to claim 1 wherein the sun gear, the planet gear, and the ring gear are fabricated from PEEK.

Claim 3: The impactor according to claim 1 wherein the stepped portion is fabricated from PEEK.