US3798680A

US3798680A - Universal wrist system

Info

Publication number: US3798680A
Application number: US00241221A
Authority: US
Inventors: W Prout
Original assignee: Parke Davis and Co LLC
Current assignee: Professional Medical Products Inc
Priority date: 1972-04-05
Filing date: 1972-04-05
Publication date: 1974-03-26
Anticipated expiration: 1991-03-26

Abstract

A universal wrist system in which terminals with different types of shafts and different types of mountings may be used. A wrist forearm connector member is adapted to be molded into a prosthetic forearm. The wrist forearm connector member has a passage therethrough and a substantially flat ring-shaped mounting surface positioned at one end of the passage and extending around the opening into the passage. At least one opening is provided into the surface of the forearm connector member. A removable terminal mounting unit has a boss, an elongated receptable extending into the boss, an opening for receiving the shaft of a terminal device and a connector to secure the shaft of the terminal device in the receptacle. A ring-shaped surface surrounds the boss and is adapted for mounting in abuttment with the wrist forearm connector face with the boss extending into the passage of the wrist forearm connector member. At least one opening is provided in the surface of the removable terminal mounting unit. A locking member is removably extendable between the openings of both of the surfaces for rigidly securing the surfaces of the wrist forearm connector and the terminal mounting unit together.

Description

United States Patent [191 Prout i 1 UNIVERSAL WRIST SYSTEM [75] Inventor: Wesley C. Prout, St. Anne, Ill.

[73] Assignee: Parke, Davis & Company, Detroit,

Mich.

[221 Filed: Apr. 5, 1972 [21] Appl. No.: 241,221

OTHER PU BLlCATlONS The UpperExtremity Prosthetics Armamentarium by M. J. Fletcher, Artificial Limbs, National Academy of Sciences, National Research Council, Jan. 1954, pages l7-18 relied upon.

New Developments in Artificial Arms" by M. J. Fletcher et al., in Human Limbs & Their Substitutes by Klopsted & Wilson et al., 1954, Chapter 10, pages 278285 relied upon.

[ Mar. 26, 1974 Primary Examiner-Richard A. Gaudet Assistant ExaminerRonald L. Frinks Attorney, Agent, or FirmChristie, Parker & Hale [57] ABSTRACT A universal wrist system in which terminals with different types of shafts and different types of mountings may be used. A wrist forearm connector member is adapted to be molded into a prosthetic forearm. The wrist forearm connector member has a passage therethrough and a substantially flat ring-shaped mounting surface positioned at one end of the passage and ex tending around the opening into the passage. At least one opening is provided into the surface of the forearm connector member. A removable terminal mounting unit has a boss, an elongated receptable extending into the boss, an opening for receiving the shaft of a terminal device and a connector to secure the shaft of the terminal device in the receptacle. A ring-shaped surface surrounds the boss and is adapted for mounting in abuttment with the wrist forearm connector face with the boss extending into the passage of the wrist forearm connector member. At least one opening is provided in the surface of the removable terminal mounting unit. A locking member is removably extendable between the openings of both of the surfaces for rigidly securing the surfaces of the wrist forearm connector and the terminal mounting unit together.

12 Claims, 8 Drawing Figures PATENTED MR 2 6 I974 SHEEI 1 [1F 3 PATENTEDNARZB 1914 3798680 SHEET 2 BF 3 UNIVERSAL WRIST SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to prosthetic wrist apparatus of the type used between a prosthetic arm and a prosthetic terminal device.

2. Description of the Prior Art A prosthetic wrist is used for connecting a prosthetic terminal device such as a hand or a hook to a prosthetic arm. Generally the known prosthetic wrist is a unit which is specially adapted for providing a specific type of mounting for a terminal device.

For example, a friction type prosthetic wrist unit is known which has a body portion adapted to be molded onto the end of a prosthetic forearm. The body portion has a cavity at one end with a threaded bushing extending through the bottom of the cavity. A ring-shaped rubber cushion with a ring-shaped metallic cover is positioned into the cavity. The threaded shaft of a terminal mates with the threaded bushing and frictionally engages the metallic cover.

By way of further example, a wrist disconnect type unit has a body portion which is adapted to be mounted in the end of a prosthetic forearm. The body portion is an integral part of a locking mechanism for securing a terminal device on the end of the prosthetic forearm. To this end, the body portion has a passage therethrough and is adapted to slidably mount a yoke locking mechanism. A spring biases the yoke to a locked position which is in an interferring relation in the passage through the body. An internally threaded tubularshaped insert is placed in the passage. A groove in the insert forms an interferring fit with the spring biased yoke. A terminal device with a threaded shaft mates with the threaded insert.

A further example is a quick-disconnect wrist unit that has a body portion adapted to be molded on the end of a prosthetic forearm and, as an integral part thereof, a tubular portion projects out of the end of the body portion. A ring-shaped face fits over the tube and a groove is provided in the tube around which a retainer ring fits to hold the face in place. Again, an internally threaded insert is inserted into the end of the assembly and a terminal with a threaded shaft mates with the threaded insert.

Another prosthetic wrist unit has been proposed which has a tubular-shaped body portion adapted to be molded onto the end of a prosthetic forearm. The tubular body member has a circular opening therein into which a prefabricated tubular-shaped insert is placed. The insert has a threaded opening therein with a plastic insert for receiving the threaded shaft of a terminal device. The insert is placed into the opening of the body portion and a set screw is passed through the side of an axially elongated disk-shaped portion to engage the side of the plastic insert frictionally engaging the shaft of the terminal device so that it does not rotate.

Another prosthetic wrist unit is known which allows the terminal to rotate. in such an arrangement, a tubular-shaped body portion is adapted to be molded or otherwise affixed to a prosthetic forearm. Two coneshaped oilite bearings are installed on the body portion, one on the outside and one on the inside of inwardly flanged surfaces on the tubular-shaped body portion. The assembly is made specifically for the aforementioned type of terminal mounting and it is difficult to remove the mounting for the terminal because access must be gained to the inside of the body portion.

In summary, the aforementioned prior art devices suffer from the disadvantage that each is a unitary structure for a particular type of mounting. If it is desired to use a different type of mounting for a terminal device, then the body portion as well as the associated connecting parts are discarded and a different mounting is used.

SUMMARY OF THE INVENTION The present invention involves a universal wrist system and provides a very simple and inexpensive system in which terminals with different types of shafts and different types of mountings may be used. According to an embodiment of the present invention, a universal prosthetic wrist system is provided for connecting the shaft of a prosthetic terminal device to a forearm of an amputee with different types of terminal mountings. The system includes a wrist forearm connector member adapted to be molded into a prosthetic forearm. The wrist forearm connector member has a passage therethrough, a substantially flat ring-shaped mounting surface positioned at one end of the passage and extending around the opening into the passage. At least one opening is provided into the surface of the forearm connector member. A removable terminal mounting unit is also provided having a boss, an elongated receptacle extending into the boss with an opening for receiving the shaft of a terminal device, and a connector to secure the shaft of the terminal device in the receptacle. A ring-shaped surface surrounds the boss and is adapted for mounting in abutment with the wrist forearm connector face with the bo ss extending into the passage of the wrist forearm connector member. At least one opening is provided in the surface of the removable terminal mounting unit. A locking member is removably extendable between the openings of both of the surfaces for rigidly securing the surfaces of the wrist forearm connector and the terminal mounting unit together.

With such an arrangement, one basic forearm connector may be affixed to the forearm of the amputee and different removable terminal mounting units may be selected depending on the particular type of mounting desired. For example, if it is desired to have a friction wrist connection in which a threaded shaft of a terminal is screwed into a fixed position with respect to the forearm of the amputee, one removable terminal mounting unit is selected. If desired to provide a wrist disconnect type of mounting for a grooved shaft of a terminal device, the appropriate removable terminal mounting unit is selected. If desired to provide a rotational mounting for the terminal, again, the appropriate removable terminal mounting is selected. Once having selected the appropriate removable terminal mounting unit, it is merely fitted on the end of the wrist forearm connector member and secured in place.

In addition to the universal mounting, the aforementioned structure also has the advantage that the distance between the end of the forearm for the amputee and the terminal device is minimized because of the interface connection between the wrist forearm connector member and the removable terminal mounting unit. For example, if set screws and the like were to be used through the side of the forearm connector member to secure the removable terminal mounting unit in place,

the length of the wrist forearm connector would have to be increased. Minimum length of the forearm connector member is important in minimizing length of the overall assembly to allow the terminal to be handled BRIEF DESCRIPTION OF THE DRAWINGS FIG. I shows an exploded view of a universal wrist system showing a terminal device with a shaft and the dashed outline of a forearm for an amputee. A removable terminal mounting unit is shown in schematic form;

FIG. 2 shows a cross-sectional view of a friction wrist-type removable terminal mounting unit with a portion of a terminal device for use therewith;

FIG. 3 shows a cross-sectional view of a wrist disconnect type removable terminal mounting unit with a portion of a terminal unit for use therewith;

FIG. 4 shows a view of the cover plate for the wrist disconnect unit of FIG. 3 taken along the lines 44 of FIG. 3;

FIG. 5 shows a cross-sectional view of the wrist disconnect unit of FIG. 3 taken along the lines 5-5 of FIG.. 3;

FIG; 6 is a pictorial view of the yoke locking member used in the wrist disconnect unit of FIG. 3;

FIG. 7 shows across-sectional-view of a rotational type removable terminal mounting unit with a portion of a terminal device for use therewith; and

FIG. 8 shows a cross-sectional view of the rotational mounting unit taken along the lines 8-8 of FIG. 7.

DETAILED DESCRIPTION Refer to FIG. 1. FIG. 1 is an exploded view showing a prosthetic terminal device I4 and universal wrist system 10 for connecting the forearm 12 of an amputee to the shaft 14a of the prosthetic terminal device 14 through different types of terminal mountings. In the system 10a, a tubular-shaped wrist forearm connector 16 is provided which is adapted to be molded into a prosthetic forearm. To aid in molding into the prosthetic forearm 12, a groove 16a is provided adjacent to a knurled partially conical-shaped base portion 161'. The forearm connector member 16 has a passage 16a passing completely therethrough. A ring shaped collar portion extends from the groove 16a to the end of the passage 16a at the front end of the fore-arm connector 16. The inner portion of the ring-shaped collar portion is stepped inwardly into the passage 16a with respect to the other portion of the passage forming a side surface in abutting contact with a side surface 181' of the removable terminal mounting unit 183. A substantially flat, ring-shaped mounting surface 16b is positioned on the disk portion at oneend of the passage and extends completely around the opening to the passage. The five threaded openings 160 are provided equally spaced around in the surface 16b. To be explained in detail, the threaded openings 16c are provided for connecting the removable terminal mounting unit to the forearm connector 16.

Immediately above the forearm connector 16 is schematically shown the removable terminal mounting unit 18. The removable terminal mounting unit 18 has a disk-shaped portion 183 with a boss I8a extending therefrom. An elongated receptacle 18b extends through the disk-shaped portion 18g into the boss 18a with an opening for receiving the shaft 14a ofthe terminal device 14. A removable terminal mounting unit has a connector 18c (indicated by dashed lines) for securing the shaft of the terminal device in the receptacle. Examples of various connectors 18c are shown in the subsequently described embodiments of the invention. A ring-shaped surface on the underside of the disk portion 18g surrounds the boss and is adapted for mounting in abutment with the surface 161) of the wrist forearm connector such that the boss extends into the passage of the wrist forearm connector member 16. Five spaced apart openings 1811 are provided in the surface 18d of the removable terminal mounting unit 18 and are aligned with the five openings in the surface of the forearm connector member 16. A locking member l8e is provided for each of the openings in the two surfaces. In the embodiment disclosed herein, the locking member l8e is a bolt having a head forming a shoulder 18f which bears against an upper surface of the termi nal mounting unit and a threaded portion 18 which is threaded into the threaded opening 166 of the forearm connector member 16. One locking member l8e is shown and the rest are illustrated as arrows for simplicity. An additional ring-shaped boss 181? is positioned adjacent to the surface 18d and extends downward from the disk portion l8g around the boss 18a. The boss 181 has substantially the same outer shape and configuration as the adjacent portion of the passage 16a (in disk portion- 16g) to mechanically prevent sliding movement between surfaces 16b and 18d.

As depicted in FIG. 1, the wrist forearm connector member and the terminal mounting unit have substantially circular outer configurations around the respective ring-shaped surfaces of susubstantially the same outer diameter, thereby providing a universal prosthetic wrist system having a very pleasing appearance.

The terminal 14 depicted herein has a pair of pivoted hooks 14c and 14d which are normally biased closed by means of a resilient, preferably rubber, band 142. An extension member I4b may be attached to a cable or the like for actuating the hook 14c with respect to the hook 14d in the manner well known in the prosthetic art. Although a hook-type terminal device has been disclosed herein, it should be understood that other types of terminal devices may be used, such as a prosthetic hand.

With the general configuration of the universal prosthetic wrist system of FIG. 1 in mind, refer now to the frictional wrist-type terminal mounting unit depicted in FIG. 2. The same reference numerals used to identify portions of the removable terminal mounting unit and the terminal device of FIG. 1 are used to identify the corresponding parts of these devices in FIG. 2, except that a -2" is added to associate the various parts with the particular embodiment of the invention depicted in FIG. 2. Thus, a terminal 14-2 has a threaded shaft 14a- 2. A removable terminal mounting 18-2 has a diskshaped portion I8g-2, bosses 180-2 and I8i-2 extending from the disk-shaped portion 18 -2, an elongated receptacle 18b-2 extending into the boss for receiving the shaft of the terminal device, a connector l8c-2 to secure the shaft of the terminal device in place, a ringshaped surface 18d-2 to surround the boss and adapted for mounting in abutment with the face 16b of wrist forearm connector 16 with the boss extending into the passage 16a, and openings 1811 -2 in the surface 1811-2 (only one being shown in FIG. 2, it being understood that the four other openings 18h-2 are equally spaced around the surface 18i-2 and in alignment with the openings 16c of the forearm connector member). Locking members or bolts 18e-3 extend between the openings in the surfaces of the wrist forearm connector and the terminal mounting unit for securing the two together.

Consider now the particular type of mounting employed in the friction wrist terminal mounting unit of FIG. 2. The connector l8c-2 includes a further surface 22 parallel with and facing in the opposite direction from the ring-shaped surface 1811-2. The openings 18h-2 extend between the surfaces 22 and 18d-2. In this manner, the shoulder of the locking member 18e-2 bears against the surface 22 and the threaded portion of the locking member 18e-2 is threaded into the threaded opening 160 of the forearm connector member to secure the two parts together. The further ringshaped boss 18i-2 is positioned adjacent the surface 18d-2 and is of substantially the same outer shape and size as the adjacent portion of the passage through the wrist forearm connector. This configuration provides a mounting which prevents sliding movement between the surfaces 1811-2 and 16b.

The connector l8c-2 of the friction wrist mounting unit of FIG. 2 includes a threaded sleeve 26 into which the threaded shaft 14a-2 mates. The terminal mounting unit 18-2 has a circular cavity 28 at the bottom of which surface 22 is positioned. A second part 30 of the connector 18c-2 includes a ring-shaped resilient member 32 which engages the bottom portion of the cavity specifically bearing against the tops of the locking members 18e-2. The second part 30 also includes a ring-shaped cover member 34 which covers the resilient material and a base 33 of the terminal 14-2 frictionally engages the ring cover member 34, thereby securing the terminal in place in the removable terminal mounting unit 18-2.

Refer now to the wrist disconnect-type removable terminal mounting unit depicted in FIG. 3. Again, the same reference numerals used for wrist disconnect mounting the unit 18 and terminal 14 of FIG. 1 are used to indicate the corresponding parts of the wrist disconnect mounting unit of FIG. 3, except that -3 has been added to identify the specific structure of FIG. 3. Depicted in FIG. 3 is a terminal unit 14-3 having a shaft 14a-3 with a groove 38 and, exially extending from the bottom thereof, a compression spring 40. The shaft 1411-3 with the groove 38 is adapted for connection to the wrist disconnect type terminal mounting unit 18-3. The removable terminal mounting unit 18-3 includes a disk-shaped portion 18g-3, ring-shaped bosses 18a-3 and 18i-3 extending from the bottom portion of disk-portions 18g-3 adjacent to ring-shaped surface 1811-3', an elongated receptacle 18b-3 extending into boss 1811-3 for receiving the shaft 1411-3 of the terminal 14-3, a connector 180-3 and five equally spaced openings 18h-3 in the surface 18d-3. Locking members or bolts 18e-3 extend through each of the openings l8h-3 for securing the surfaces 1811-3 and 16b (FIG. 1) together.

Referring now to FIGS. 3, 5 and 6, the connector 180-3 is of the wrist disconnect-type and includes a movable yoke member 44 which moves back and forth in a transverse direction into an interferring position with respect to the receptacle 1817-3. The connector 18c-3 includes a spring 45 which normally biases the movable member 44 into the interferring position within the receptacle and thereby engages the groove 38 of the terminal 14-3, securing the terminal in place within the receptacle of the terminal mounting unit 18-3. The movable member 44 has a circular opening 48 which is large enough to allow the shaft 1411-3 of the terminal 14-3 to pass therethrough. A pair of springs 50 actuate the movable member 48 (to the right as seen in FIG. 3) against a wall of acavity 52 provided under a cover plate 54. The cover plate 54 mounts on a lower housing 56 which contains the lower portion of the receptacle 18b-3. Also included in the connector 180-3 is a locking rod 57. The locking rod 57 is provided for mating with grooves 58 provided in the bottom of the shaft 14a-3 of the terminal 14-3.

To insert the shaft of the terminal 14-3 into the terminal mounting unit 18-3, an operator actuates a handle 60 of the movable member 44 which is external to the terminal mounting unit 18-3. The handle 60 is actuated towards the terminal mounting unit, thereby compressing the spring 45 and causing the opening 48 to axially align itself with the receptacle 1817-3. The terminal 14a-3 is then inserted through the opening 48 into the receptacle 18b-3 until it is positioned with aligned grooves 58 about the rod 57 at the bottom of the receptacle 18b-3. After the shaft of the terminal 14-3 is so positioned, the handle 60 is released, allowing the spring 45 to return the movable member 44 back to the position shown in FIG. 3 and into the groove 38, thereby securing the terminal 14-3 in the receptacle l8b-3.

Two shoulders are shown in groove 38. Shoulder 38a is of smaller diameter than shoulder 38b. When shaft 1411-3 is positioned with shoulder 38b engaging the movable member 44, the bottom grooves 58 of shaft 14a-3 are out of engagement with the rod 57, allowing terminal 14-3 to be rotated and angularly adjusted. When shaft 14a-3 is positioned with shoulder 38a engaging movable member 44, the shaft is seated with grooves 58 around rod 57, preventing rotation. The spring 40 automatically forces shaft 14a-3 to the right when handle 60 is actuated, so as to move the member 44 out of engagement with either of shoulders38a or 38b.

Refer now to the rotational terminal mounting unit shown in FIGS. 7 and 8. Again, similar reference numerals to those used in FIG. 1 are used to identify the corresponding parts of the rotational terminal mounting unit of FIGS. 7 and 8. A -7 is used to specifically identify the corresponding portions of the rotational terminal mounting unit of FIGS. 7 and 8. Thus, the rotational terminal mounting unit 18-7 has ring-shaped bosses 18a-7 and 18i-7 extending from the bottom portion of disk-shaped portion 18g-7 adjacent to ringshaped surface 1811-7, an elongated receptacle l8b-7 extending into the boss 180-7 with an opening for receiving a threaded shaft 14a-7 of a terminal 14-7, a connector 18c-7 in the form of threads for securing-the shaft -7 in the receptacle 18b-7 and five equally spaced openings 1811-7 in the surface 18d-7. A connector or threaded bolt l8e-7 is provided for each opening 1811-7 for securing the surfaces 18d-7 and 16b (FIG. 1) together. The ring-shaped surface 18 11-7 is adapted for mounting in abutment with the surface 16b of the wrist forearm connector (FIG. 1), with the boss 18a-7 extending into the passage. of the wrist forearm connector member. The rotational terminal mounting unit has a housing portion 64 with a circular-shaped cavity 66 around the elongated receptacle.

The connector l8c-7 includes a tubular-shaped member 68 journaled or rotatably mounted within the housing 64 and forms a part of the elongated receptacle l8b-7. The connector 180-7 also includes a lock 70 for selectively locking the tubular-shaped member against rotation. To this end, the lock 70 has a flanged portion 72 which has'a plurality of openings 74, all at the same radial position around the flanged portion 72. The lock 70 also includes a pin 76 which is selectively engaged into the openings 74 to stop rotation of the rotatable member 68. The pin 76 is attached to a cable 78 which can be remotely actuated by the amputee. A spring 80 normally biases the pin 76 into an aligned opening 74 to lock rotation of member 68.

Also included in the connector 180-7 is a ring-shaped resilient member 82 which is positioned in the cavity 66 and bears against the flanged portion 72 of the rotatable member 68. The resilient material 82 may be rubber, plastic or other suitable material which bears against the flange 72 and, through friction, helps prevent rotation therebetween.

' A ring-shaped metallic cover 84, having a U-shaped cross-sectional configuration, covers the resilient member 82 at the exterior of the terminal mounting unit. Also included in the connector 18c-7 are threads which are formed on the inside surfaces of the rotatable tubular member 68 and on the inside surface of the ringshaped cover 84, thereby providing a mating connection for the threaded shaft 140-7 of the terminal 14-7. A base 86 of the terminal 14-7 frictionally engages the metallic cover 84, thereby preventing it from being unthreaded under normal use. Similar to the terminal mounting unit in the other figures, additional boss 18i-7 is of substantially the same outer shape and size as the adjacent portion of the passage 16a through the wrist forearm connector 16 (FIG. 1) so that when positioned together, the boss 1811-7 prevents sliding movement between the surfaces 18d-7 of the terminal mounting unit 18-7 and the surface 16b of the forearm connector member.

Although an exemplary embodiment of the invention has been disclosed for purposes of illustration, it will be understood that various changes, modifications and substitutions-may be incorporated in such embodiment without departing from the spirit of the invention as defined by the claims appearing hereinafter.

What is claimed is:

1. A universal prosthetic wrist system for connecting the forearm of an amputee to the shaft of a prosthetic terminal device through different types of terminal mountings, the combination comprising:

a. a tubular-shaped wrist forearm connector comprising a member having front and back ends and adapted to be molded into a prosthetic forearm, the member comprising:

2. a first circular passage extending therethrough from the front end to the back end having a first ring-shaped side surface;

2. an annular groove around the perimeter of said connector and positioned towards the front end thereof into which a forearm may be molded; a ring-shaped collar portion extending from the groove to the end of the passage at said front end and having, at its front end, a substantially flat, ring-shaped front mounting surface extending around said passage, the inner portion of said ring-shaped collar portion being stepped inwardly into said passage with respect to other portions of said passage and forming said first side surface; and

4. at least one opening into said front mounting surface;

b. a removable terminal mounting unit having front and back ends and an outer perimeter in between the ends comprising:

1. a disk-shaped portion having a front end and a boss extending in the opposite direction from a back end of the removable terminal mounting unit, the boss comprising a second ring-shaped side surface in abutting engagement with said first side surface;

2. an elongated receptacle in the boss and opening out of the front end of the disk-shaped portion for receiving the shaft of a terminal device;

3. A connector for securing the shaft of the terminal device in said elongated receptacle;

4. a back flat annular-shaped mounting surface on the disk-shaped portion towards the back end of said terminal mounting unit surrounding said boss and in abutment with the wrist forearm connector member front mounting surface with said boss extending into the passage of said wrist forearm connector member; and

5. at least one opening in said back mounting surface alignable with the opening in said front mounting surface;

c. the forearm connector comprising a construction adjacent the front mounting surface thereof, allowing unobstructed access to such front mounting surface for the outer perimeter of said removable mounting unit as the latter is mounted and removed from such front mounting surface; and

d. a locking member removably extending between the openings in both said front and back mounting surfaces for rigidly securing such surfaces of the wrist forearm connector and terminal mounting unit together.

2. A universal prosthetic wrist system according to claim 1 wherein said wrist forearm connector and removable terminal mounting unit have outer structural configurations around the respective ring-shaped surfaces of substantially the same perimeter.

3. A universal prosthetic wrist system according to claim 1 wherein said boss of said removable terminal mounting unit comprises a further ring-shaped side surface inwardly stepped from the second side surface so as to be spaced away from the side of the first circular passage of said forearm connector.

4. A universal prosthetic wrist system according to claim 1 wherein said removable terminal mounting unit comprises a front facing surface facing in substantially the opposite direction from the back mounting surface thereof, the opening to the back mounting surface of the removable terminal mounting member extending from the back mounting surface to the front facing surface, the locking member comprising a shoulder engaging the front facing surface and a threaded portion threaded into the opening in the front mounting surface of the wrist forearm connector to thereby secure the front and back mounting surfaces together.

5. A universal prosthetic wrist system according to claim 1 wherein the connector in the receptacle of the removable terminal mounting unit comprises threads in the receptacle for receiving a threaded shaft on a terminal device.

6. A universal prosthetic wrist system according to claim 1 wherein the removable terminal mounting unit comprises a ring-shaped cavity area around said elongated receptacle having a bottom structure and a second connector part comprising a first ring shaped resilient member for engaging the bottom structure of said cavity and a second ring-shaped member covering said resilient material against which a terminal device may bear, said receptacle comprising threads for receiving a threaded shaft on a terminal device.

7. A universal prosthetic wrist system according to claim 1 wherein the connector in the receptacle of the removable terminal mounting unit comprises a member movable in the elongated receptacle in a transverse di rection to the receptacle.

8. A universal prosthetic wrist system according to claim 7 comprising spring bias means for normally biasing said movable member into an obstructive position in said receptacle to secure a groove shaft of a terminal device in place.

9. A universal prosthetic wrist system according to claim 8 comprising a member rigidly connected across said receptacle for engaging a groove in the end of a terminal device shaft and thereby locking the angular position of the shaft.

10. A universal prosthetic wrist system according to claim 1 wherein the connector of the removable terminal mounting unit comprises:

a. a ring-shaped cavity around said elongated receptacle;

b. a rotatable tubular-shaped member mounted in said elongated receptacle;

c. means for selectively locking said tubular-shaped member against rotation; and

d. a ring-shaped member positioned in said cavity and comprising a resilient portion bearing against an end of said tubular-shaped member.

11. A universal prosthetic wrist system according to claim 10 wherein said elongated receptacle comprises threads in the side thereof for receiving a threaded shaft of a terminal device.

12. A universal wrist system according to claim 1 wherein said connector in said removable terminal mounting unit comprises a rotatable mounting for the shaft of the terminal device and a controllable lock for preventing rotation thereof, a cable connected to said lock for controlling the locking thereof and extending through said passage.

UNITED STATES PATENT OFFICE CERTIFICATE OF CGRRECTION Patent No. 3,798,680 Dated Mar. 26 1974 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 4, line 40, "susubstantially" should read I substantially; Col. 5, line 11, "l8e-3" should be -l8e-2; line '55, "exially" should be axially--; Col. 7, line 49, "l8a-7" should be l8i-7'; Col. 8, line 1, "2" should be --l-; Col. 10, line 1, "groove" should be grooved.

Signed and sealed this 17th day of September 1974.1

(SEAL) Attest: H

MCCOY M. GIBSON JR. C. MARSHALL DANN L Attesting Officer Commissioner of Patents

Claims

1. A universal prosthetic wrist system for connecting the forearm of an amputee to the shaft of a prosthetic terminal device through different types of terminal mountings, the combination comprising: a. a tubular-shaped wrist forearm connector comprising a member having front and back ends and adapted to be molded into a prosthetic forearm, the member comprising: 2. a first circular passage extending therethrough from the front end to the back end having a first ring-shaped side surface; 2. an annular groove around the perimeter of said connector and positioned towards the front end thereof into which a forearm may be molded; 3. a ring-shaped collar portion extending from the groove to the end of the passage at said front end and having, at its front end, a substantially flat, ring-shaped front mounting surface extending around said passage, the inner portion of said ring-shaped collar portion being stepped inwardly into said passage with respect to other portions of said passage and forming said first side surface; and 4. at least one opening into said front mounting surface; b. a removable terminal mounting unit having front and back ends and an outer perimeter in between the ends comprising: 1. a disk-shaped portion having a front end and a boss extending in the opposite direction from a back end of the removable terminal mounting unit, the boss comprising a second ring-shaped side surface in abutting engagement with said first side surface; 2. an elongated receptacle in the boss and opening out of the front end of the disk-shaped portion for receiving the shaft of a terminal device;

2. an annular groove around the perimeter of said connector and positioned towards the front end thereof into which a forearm may be molded;

3. A connector for securing the shaft of the tErminal device in said elongated receptacle; 4. a back flat annular-shaped mounting surface on the diskshaped portion towards the back end of said terminal mounting unit surrounding said boss and in abutment with the wrist forearm connector member front mounting surface with said boss extending into the passage of said wrist forearm connector member; and 5. at least one opening in said back mounting surface alignable with the opening in said front mounting surface; c. the forearm connector comprising a construction adjacent the front mounting surface thereof, allowing unobstructed access to such front mounting surface for the outer perimeter of said removable mounting unit as the latter is mounted and removed from such front mounting surface; and d. a locking member removably extending between the openings in both said front and back mounting surfaces for rigidly securing such surfaces of the wrist forearm connector and terminal mounting unit together.

3. a ring-shaped collar portion extending from the groove to the end of the passage at said front end and having, at its front end, a substantially flat, ring-shaped front mounting surface extending around said passage, the inner portion of said ring-shaped collar portion being stepped inwardly into said passage with respect to other portions of said passage and forming said first side surface; and

4. at least one opening into said front mounting surface; b. a removable terminal mounting unit having front and back ends and an outer perimeter in between the ends comprising:

5. at least one opening in said back mounting surface alignable with the opening in said front mounting surface; c. the forearm connector comprising a construction adjacent the front mounting surface thereof, allowing unobstructed access to such front mounting surface for the outer perimeter of said removable mounting unit as the latter is mounted and removed from such front mounting surface; and d. a locking member removably extending between the openings in both said front and back mounting surfaces for rigidly securing such surfaces of the wrist forearm connector and terminal mounting unit together.

6. A universal prosthetic wrist system according to claim 1 wherein the removable terminal mounting unit comprises a ring-shaped cavity area around said elongated receptacle having a bottom structure and a second connector part comprising a first ring-shaped resilient member for engaging the bottom structure of said cavity and a second ring-shaped member covering said resilient material against which a terminal device may bear, said receptacle comprising threads for receiving a threaded shaft on a terminal device.

7. A universal prosthetic wrist system according to claim 1 wherein the connector in the receptacle of the removable terminal mounting unit comprises a member movable in the elongated receptacle in a transverse direction to the receptacle.

10. A universal prosthetic wrist system according to claim 1 wherein the connector of the removable terminal mounting unit comprises: a. a ring-shaped cavity around said elongated receptacle; b. a rotatable tubular-shaped member mounted in said elongated receptacle; c. means for selectively locking said tubular-shaped member against rotatioN; and d. a ring-shaped member positioned in said cavity and comprising a resilient portion bearing against an end of said tubular-shaped member.