DE1269066B - Impact wrench - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN fflßWWl · PATENT OFFICE

EDITORIAL

Int. CL:

B 25b

Number:
File number:
Registration date:
Display day:

German KL: 87 a-13

P 12 69 066.3-15
March 29, 1957
May 22, 1968

The invention relates to an impact wrench with an anvil and coaxial arrangement Hammer around a constantly running intermediate shaft, the rotation of which - depending on the load torque on the tool head - continuously through contact or intermittently through impact on claw surfaces on the Anvil is transferred, for which purpose a driver arrangement is used, which runs along flat, axially parallel sliding surfaces on the hammer in or out of engagement with the ring path of the anvil claws, what comes from Mass forces of rotating parts is caused by positive cam pairs.

A rotary impact wrench of this type is known, and rotary impact tools with in Axial direction or in the radial direction sliding bolts or other shaped impact parts that be brought into clutch engagement by centrifugal force. To support the centrifugal force was also uses compressed air. Springs were already used for uncoupling. The work of the mentioned parts ao however, this known rotary percussion tool does not correspond to an inevitable, form-fitting one Work so that known tools of this type can be unreliable.

It is the object of the invention to develop a curve as to train control for withdrawing and advancing the impact part so that an inevitable, form-fitting control is created in which the impact part at the time of the impact completely into the Path of the anvil claw is advanced.

This is achieved according to the invention in an impact wrench of the type described at the outset achieves that the anvil on the outer edge of its flange carrying the tool head has a ring segment shape Claw with radial surfaces and one of the holes around its intermediate shaft serving as a bearing Has anvil claw arranged diametrically opposite the eccentric approach, the one as a counter cam Cylinder segment jacket surface concave to the intermediate shaft on the driving claw of a coupling sleeve (Carrier arrangement) is assigned to secure the entrainment of the anvil while for interruption this entrainment on the drive shaft a cam of egg-shaped cross-section is provided which symmetrically in a recess similar but larger cross-section in the flange of the coupling sleeve is attached between their sliding surfaces.

In the drawings, an embodiment of the impact screwdriver according to the invention is shown; it shows

F i g. 1 shows a vertical longitudinal section with the impact coupling in the uncoupled state,

Impact wrench

Applicant:

Thor Power Tool Company,

Aurora, JIl. (V. St. A.)

Representative:

Dr.-Ing. H. Ruschke, patent attorney,

8000 Munich 27, Pienzenauer Str. 2

Named as inventor:

Frank A. Kaman, Aurora, JU. (V. St. A.)

Claimed priority:

V. St. v. America April 5, 1956 (576 477)

F i g. 2 shows a horizontal longitudinal section along line 2-2 of FIG. 1, seen in the direction of the arrows,

F i g. 3 an exploded view of the most important parts of the impact coupling with impact spindle, Drive shaft, impact coupling sleeve and hammer housing in a diagrammatic view,

F i g. 4 shows a partial cross section along line 4-4 of FIG. 1, seen in the direction of the arrows,

F i g. 5 shows a partial cross section along line 5-5 of FIG. 1, seen in the direction of the arrows,

F i g. 6 to 13 front views of certain drive parts detached from the other parts of the tool, in these figures the relative position of these parts in different phases of a stroke cycle are shown.

The in the F i g. 1, 2 and 3 shown rotary impact tool consists of a handle part 21 provided rear housing section 20 and a front housing section 22. Der front housing section 22, which contains the impact coupling, is on the rotating air motor 23 containing rear housing part 20 with the aid of a threaded ring 24 attached. The air motor 23 can be a reversible vane motor, the drive motor shaft 26 of which is connected to it is mounted in ball bearings 27 and 28 at its front end and rear end. To drive the motor 23 is Compressed air is supplied via an air duct 30 located in the handle 21. The air duct 30 is in lower part of the handle with a screw thread bore 31 via a ball valve 32

809 550/127

bound to open or close the air supply in the usual manner by a switch lever 33 and a piston 34. From the duct 30 the air flows through a manually operable reversing valve 35 and through one of two ducts 29 (only one duct 29 is shown in FIG. 1) in the housing section 20 to the motor 23, around the motor 23 depending on the position of the valve 35 to drive in one or the opposite direction of rotation. The exhaust air flows from the
above

The impact coupling sleeve 50 has parallel flat surfaces 59 that are parallel to a diameter between directed and protruding forward guide segments 60 of the hammer 61 added will. The guide segments 60 have corresponding flat guide surfaces on their inner sides 62. The coupling sleeve 50 is constantly guided in a straight line by the hammer guides 60 when they when the anvil eccentric disc cooperates

Motor 23 via an exhaust port 29 'and io 45 and the one located on the coupling sleeve 50 the valve 35 and is then brought into the coupling position by one in the cam 56 or

Tool body located, not shown, when they are through the cooperation of the Opening derived. Intermediate shaft 44 located cam 51 and the

The front housing 22 has at its front end located on the coupling sleeve 50 cam end a central bore 36 in which a 15 surface is brought into the uncoupling position. Bh bf

Bushing 37 is located, which serves as a bearing for a rotatable anvil 38. The one that protrudes outwards The end of the anvil 38 has a square 39 as a drive on which the workpiece gripping

Parts, e.g. B. receptacles, not shown, releasably be 20 coupling sleeve 50 can be fastened. The one inside the case
22 located rear portion of the anvil 38 has
a flange 40 with parallel sides and opposite, rounded front ends,
which extends up to close to the inner wall of the housing 22
extend. A circular arc-shaped impact claw 41 is
arranged outside on the back of the flange 40 and protrudes axially in the drive direction from the
Anvil flange 40 out. The striking claw 41 has
Contact surfaces 42 and 43 for one or the other
opposite direction of rotation. On the back of the
Anvil 38 is one with the anvil off
one piece manufactured eccentric disk 45. The
Eccentric disk 45 is offset eccentrically by 180 °
opposite to the striking claw 41.

An intermediate shaft 44 of the rotary impact tool
is with its front end in a central hole of the
rear part of the anvil 38 and extends through the eccentric disk 45. The _w _ rear end of the intermediate shaft 44 has a square 40 shows that when a screw nut or edge 47 is tightened, which engages with a square of a screw bolt in different Phases of the opening 48 at the front end of the motor shaft 26 is. Impact cycle of the cam 51 of the intermediate shaft Thus, the drive of the shaft 44 takes place through the 44 and the coupling sleeve 50 with its claw 52 motor shaft 26. The intermediate shaft 44 passes through a and cam 56 with respect to the anvil 38, its egg-shaped cam opening 49 a transversely shifts - 45 impact claw 41 and its eccentric 45 occupied ble and revolving coupling sleeve 50. The will. In Fig. 6, the guide elements 60 of the intermediate shaft 44 has a cam 51, the radial hammer 61, in which the coupling sleeve 50 protrudes into the shaft 44 and slides within the egg-shaped path or out of the path of the anvil claw, in the cam opening 49. The cam 51 is shown in section. For clarity, however, contact with the inner surfaces of the cam opening 50, these guide segments 60 in Figs. 7-13 are gone-49 when relative rotation has been allowed between these parts. When loosening a screwed one takes place. The transversely displaceable coupling sleeve 50 part works in the opposite direction, has at its one radial end an axially and radially For tightening a screw nut or a protruding impact claw 52 with striking surfaces 53 and screw bolt, the first one on the anvil four-54, which is attached to the working with it Fastened conical socket 39, not shown, place a screw nut or the screw bolt head over the contact surfaces 42 or 43 of the anvil claw 41 or hit these surfaces. The front is set and then the shift lever 33 is operated so that the surface of the coupling sleeve 50 is flat, so that it flows to the compressed air motor 23 on compressed air and the motor of the flat rear surface of the anvil eccentric disk rotates in the tightening direction. The motor shaft 26 45 slides. The transversely displaceable coupling sleeve 60 drives the intermediate shaft 44 of the rotary hammer mechanism 50, in direct connection with the tool, which in turn controls the hammer 61 via an arcuate cam 52, the drive shaft cam 51 and the sliding segment 56 with an inner, partially cylindrical surface impact coupling sleeve 50 drives. Rotate all parts

The hammer 61 has a relatively large mass in order to transmit high impact energy. The hammer 61 can rotate with the anvil 38 or relative to the anvil 38, depending on whether it is coupled to the anvil pawl 41 or not. The hammer 61 has a central bore 63 through which the drive shaft 44 passes. The hammer 61 is rotatably mounted on the intermediate shaft 44 so that a rotation of the drive shaft 44 relative to the hammer 61 can take place at certain working stages of the striking tool. A washer 64 provided on the intermediate shaft 44 is let into a recess 66 on the rear side of the hammer 61. The rear side of the washer 64 protrudes beyond the rear side of the hammer 61 and rests against the front side of the inner ring of a ball bearing 28. In this way, any pressure exerted on the front end of the square anvil 39 serving as a tool holder is transmitted directly to the ball bearing 28 without the coupling sleeve 50 and the hammer 61 jamming against the rear of the eccentric disk 45.
In the F i g. 6 to 13 are the relative positions

on, which at certain points of the working cycle on the control surface 58 of the anvil eccentric 45
applies to the impact coupling sleeve 50 in the web
to advance the striking claw 41, as will be done later
will be described in detail.

clockwise (right-hand rotation) as shown in FIGS. 6 to 13.

F i g. 6 shows the slidable impact coupling sleeve 50 in its radially fully advanced position, in which the striking surface 53 of its striking claw 52 in

is in full engagement with the striking surface 42 of the anvil pawl 41 so that the motor torque is transmitted to the anvil 38. This will tighten the nut or bolt. F i g. Figure 6 shows the position these parts assume when an impact occurs or when the nut or bolt is screwed into the tightening position. In this stage of the cycle, the befindliehe near the narrower outer end of the Zwischenwellennockens 51 side cam surface 51 is α to the located close to the tapered end of the egg-shaped cam hole 49 of the coupling sleeve 50 point 49 a to establish a driving connection between these parts. Like F i g. 6 shows, the arcuate cam surface 57 of the coupling sleeve 50 is out of engagement with the anvil cam disk 45 so that the two cams are ineffective at this point in the cycle.

It is now assumed that a loose nut or screw bolt is to be screwed into the tightened position. The intermediate shaft 44 and its cam 51, the sliding coupling sleeve 50, the hammer 61 and the anvil 38 then rotate together in a clockwise direction, as shown in FIG. 6, and maintain their relative positions as long as the nut or the screw bolt is proportionate can rotate freely. If the screw nut or the screw bolt approach the end position, then the resistance of the screw nut or the screw bolt against rotation increases, with the result that the anvil 38 and its striking claw 41, furthermore the sliding coupling sleeve 50 and the hammer 61 slow down their rotation and to the Come to a standstill when the resistance to rotation is so great that it cannot be overcome by the steady motor torque being transmitted. The intermediate shaft 44, however, continues to rotate below the engine torque. The driving force exerted by the drive shaft cam 51 against the inner cam surface 49 of the coupling sleeve 50 pushes the coupling sleeve 50 radially inward into the position shown in FIG. 7, in which the striking claw 52 of the coupling sleeve 50 is uncoupled and its engagement with the anvil claw 41 is released. When retracting, the coupling sleeve 50 also slides relative to the intermediate shaft cam 51. The point of engagement between these parts shifts from the point 49 α to the point 49 b, which is located relatively inward of the cam opening 49, as shown in FIG. 7 shows. The coupling sleeve 50 slides laterally in a straight direction during its retraction movement described above and during its advancing movement, which will be described later, since it is guided by the guide segments 60 of the hammer 61. These guide segments 60 also prevent relative rotation between the coupling sleeve 50 and the hammer 61 so that the cam action and the corresponding retraction or advancement of the coupling sleeve 50 is facilitated. After the coupling claw 52 has been withdrawn into the position shown in FIG. In the position shown in FIG. 7, the coupling sleeve 50 and the hammer 61 can rotate relative to the anvil 38, which is now fixed, and its striking claw 41. This rotation takes place by the torque of the intermediate shaft 44 via the cam 51. However, due to the moment of inertia of the relatively large mass of the hammer 61 and the coupling sleeve 50, which must be set in circulation, the cam action between the cam 51 and the coupling sleeve 50 is limited Size continued to act, so that the coupling sleeve 50 in the in F i g. 8 comes fully retracted position in which the point 51 α of the cam 51 has moved to the point 49 c of the cam opening 49. At this point in the working cycle, the inner circumferential surface 49 d located at the wider end of the cam opening 49 of the coupling sleeve 50 is brought into engagement with the drive shaft 44 at the point 44 α , so that further retraction of the coupling sleeve 50 is prevented.

In the in F i g. 8 position of the working cycle, in which the coupling sleeve 50 is completely withdrawn, the arcuate cam surface 57 of the cam segment 56 of the coupling sleeve 50 is at a distance from and out of contact with the cam surface 58 of the now fixed anvil eccentric 45. Upon further rotation of the cam 51 and the Coupling sleeve 50 and shortly before the in F i g. 9 phase of the working cycle, however, the front edge 57 α of the arcuate cam surface 57 of the coupling sleeve 50 rests on the surface 58 of the anvil eccentric 45 at a point which is somewhat to the left from the contact point 58 α (FIG. 9). When the cam surface 57 rests against the anvil eccentric 45, a second cam action occurs which pushes the coupling sleeve 50 back into its advanced position. After the coupling sleeve 50 has passed the surface 43 of the anvil claw 41, the coupling sleeve is quickly turned outwards into the position shown in FIG. 9, partially advanced position shown. During the outward movement of the coupling sleeve 50, the contact point 51 α located on the drive cam 51 also changes its cam engagement point with the inner cam surface 49 and moves from the contact point 49 c to the contact point 49 b.

With a further continued rotation of the drive shaft cam 51 and the coupling sleeve 50, the points of contact between the cam disk surface 58 and the coupling sleeve surface 57 gradually shift to the points 58 b and 57 b, as FIG. 10 shows. Since the distance from the axis of the drive shaft 44 gradually increases from the point 58 α to the point 58 b , the coupling sleeve 50 is moved radially outward relative to the hammer guide segments 60. Like F i g. 11 shows, as the intermediate shaft cam 51 and the coupling sleeve 50 continue to rotate, the contact points between the anvil cam surface 58 and the coupling sleeve cam surface 57 gradually move to the points 57 c and 58 c located on the associated circumferences. The point 58 c lies on the eccentric disk 45 at the furthest distance from the axis of the intermediate shaft 44, while the point 57 c lies at the middle point of the coupling sleeve cam disk 57, so that in this phase of the cycle the coupling sleeve 50 has reached its fully advanced position and now lies in the path of the anvil claw 41. The radius of curvature of the cam surface 57 of the coupling sleeve 50 is greater than the radius of curvature of the cam surface 58 of the eccentric disk 45.

With continued rotation of the cam 51 and the coupling sleeve 50 via the shown in FIG.

Asked position also in the in F i g. 12, the arcuate cam surface 57 of the coupling sleeve 50 remains in contact with the eccentric disk 45, which serves to hold the coupling sleeve 50 in the fully advanced position. Like F i g. 12 shows, the arcuate cam surface 57 and the eccentric disk 45 touch each other at the points 57 d and 58 d, the point 57 d being the rear edge of the cam segment 57. Then turns exercised. The force tending to advance the coupling sleeve 50 overcomes the force which is tending to retract the coupling sleeve, and as a result, the coupling sleeve is advanced into the path of the striking claw 41 in a positive motion. In this process, the arcuate cam surface 57 of the coupling sleeve 50 is held in sliding contact with the control surface of the anvil eccentric 45 by the force resulting from the contact between the coupling

the cam segment 57 from contact with io ventilation sleeve 50 and the cam 51 of the intermediate

the eccentric 45 out.

Rotate the coupling sleeve 50 and the Cam 51 beyond the position shown in FIG into the in F i g. 6, then the one coupled to the mass of the hammer 61 hits Coupling sleeve claw 52 on anvil claw 41 with a hammer blow and rotates anvil 38 a limited distance so that the nut or bolt is tightened more wave 44 originates.

When the coupling sleeve 50 is moved from the retracted position (FIG. 7) to the advanced position Position or impact position (Fig. 6) attempts the one that arises when the coupling parts rotate Centrifugal force to move the coupling sleeve 50 into the advanced position. This centrifugal force however, it is not an essential factor in the operation of the machine tool. When turning the clutch

will. After the end of the strike, the share of the 20 in F i g. 9 position shown on the Boß 38, the hammer 61 and the coupling sleeve 50 in FIG. 11 position is the force that the

stopped again in the clockwise rotation, while the intermediate shaft 44 and its cam 51 are below the Continue turning the drive torque of the motor 23 so that the coupling sleeve 50 is uncoupled from the anvil 38 will. Then the working cycle, as shown in FIG. 6 to 13 described, repeated, and the hammer blows are repeated until the nut or bolt is in the tightened as desired.

On the basis of Fi g. 9 to 11 it should be noted that the point at which the cam surface 51 a of the cam 51 touches the circumference of the inner cam surface 49 of the coupling sleeve 50 gradually returns to the smaller diameter end or narrower end of the cam opening 49 from the contact point 49 c to the point of contact 49 α, as in FIG. 11 shown moved. For the remainder of the cycle, the contact point 51 α remains essentially on

the point 49 α of the coupling sleeve 50, and the drive 40 is exercised, is still present, but the drive remains via these points until the impact. In the case of coupling sleeve 50 due to the

Coupling sleeve tries to move outward to the advanced position, the cam force that is generated by the contact between the coupling sleeve 50 and the eccentric disk 45. the Any centrifugal force that is present supports the inevitable cam force when the coupling sleeve moves 50 in the advanced position, but is of little importance.

During the rotary movement of the coupling sleeve 50 from its shown in Fig. 11, completely withdrawn Position in the in F i g. 6 is the cam surface 57 of the coupling sleeve 50 except for contact with the eccentric disk 45, which is ineffective at this point in the cycle because it is already has advanced the coupling sleeve to its impact position. The uncoupling force exerted by the Driving engagement between the cam 51 and the inner cam surface 49 of the coupling sleeve.

the decoupling movement, these contact points change again, as shown in FIG. 6 to 13 and the cycle is repeated.

The engine torque is applied to the coupling sleeve 50 and then to the hammer 61 through the Transfer cam contact between the drive shaft cam 51 and the coupling sleeve 50, however, this has resident friction and the centrifugal force that is effective on the entire cycle this phase also occurs, still in its advanced position, so that the coupling sleeve claw 52 strikes the anvil claw 41 with its full surface.

As a result of the symmetrical design of the various parts of the striking tool, it is possible to the rotary impact tool in both directions of rotation

Cam engagement the effort to actuate the coupling sleeve 50. The reversing valve 35 is used for this purpose to decouple or set inward out of engagement with chend. As when loosening a screw connection the anvil claw 41 or from the path of the anvil- the workpiece is initially tightened, brings the claw 41 to pull. However, if the eccentric coupling sleeve 50 at the beginning of the work cycle 45 when it comes into contact with the cam surface 57 of the hammer blows on the anvil claw 41, Coupling sleeve 50 becomes effective, as shown in FIG. 9, these blows being continued until is set, then a second, opposite, the resistance exerted by the workpiece is smaller

as the driving torque of the intermediate shaft cam 51. Then the hammer blows stop, and the coupling sleeve 50 remains in constant contact with the anvil 38 so that all parts are common turn. The tool then remains in operation for that long

directed force is exerted on the coupling sleeve 50 and pushes it into coupling engagement or into its advanced Position.

Shortly before the position shown in FIG. 9 and up to the position shown in FIG. 2 position shown at the same time on the coupling sleeve 50 - because of the two at a distance from each other standing cam contact points on the coupling sleeve 50 - a force that the coupling sleeve 50 tries to retract from its advanced position, and a force that the coupling sleeve 50 tries to move into its advanced position, touching the workpiece to be screwed until the workpiece has completely unscrewed from the thread.

The simplicity of construction results in low manufacturing costs and enables easy maintenance. Due to the very strong design, the risk of breakage is reduced to a minimum.

As the decoupling of the impact coupling sleeve 50 and its return movement into the path of the anvil claw 41 take place positively, no springs or slingshot devices are required. The compensation the internal forces due to the structure according to the invention leads to a tool that is comfortable and low-vibration can be handled.

The rotary impact tool according to the invention can by special tool holders on the anvil square 39 among other things also for drilling, screwing with a screwdriver, thread cutting, Find grinding, polishing or as a wire brush drive use. When used to such For the purposes of this, the tool runs mainly continuously without acting like an impact tool work. When used as a screwdriver or drill, it is the appropriate tool hindered in its rotation, then the rotary impact effect occurs automatically in order to increase resistance to overcome at the drive.

ao

Claims (1)

Claim: Impact wrench with an equiaxed arrangement of anvil and hammer around one Constantly running intermediate shaft, its rotation - depending on the load torque on the tool head - steadily through contact or intermittently through impact on the claw surfaces on the anvil will carry, including a driver arrangement that comes along flat, axially parallel sliding surfaces on the hammer in or out of engagement with the annular path of the anvil claws, which is caused by inertia forces of rotating parts via positive cam pairs, characterized in that the anvil (38) on the outer edge Its flange (40) carrying the tool head (39) has a ring segment-shaped claw (41) with radial surfaces ( 42, 43) and around its bore (46) serving as a bearing for the intermediate shaft (44) an eccentric projection (41) arranged diametrically opposite the anvil claw (41). 45,58), to which a cylinder segment jacket surface (57) concave to the intermediate shaft (44) on the driving claw (52) of a coupling sleeve (50) (driving arrangement) is assigned as a counter-cam in order to secure the driving of the anvil while this driving is interrupted on the intermediate shaft (44) a cam (51) of egg-shaped cross-section is provided, which in a recess (49) similar but larger cross-section in the F flange of the coupling sleeve (50) is attached symmetrically between its sliding surfaces (59). Considered publications:
U.S. Patents Nos. 2,373,664, 2,373,665,
425 793, 2,636 583. 1 sheet of drawings 809 550/127 5.68 © Bundesdruckerei Berlin