US2580631A

US2580631A - Impact tool

Info

Publication number: US2580631A
Application number: US666707A
Authority: US
Inventors: Edgar R Whitledge
Original assignee: Reed Roller Bit Co
Current assignee: Reed Roller Bit Co
Priority date: 1946-05-02
Filing date: 1946-05-02
Publication date: 1952-01-01
Anticipated expiration: 1969-01-01

Description

Jan- 1 1952 E. R. wHlTLEDGE 2,580,631

IMPACT Tool.

Filed May 2, 1946 3 Sheets-Sheet l INVENTOR. EDGAR R. WHITLEDGE ATTORNEYS Jan. 1, 1952 `RWI-"11511165:

IMPACT TooL 3 Sheets-Sheet 2 Filed May 2, 1946 Fla@ FIG.5

INVENTOR. EDGAR R. VIHITLEDGE ATTORNEYS Jan. 1, 1952 E. R.wH1T1.EDGE

IMPACT TOOL 3 Sheets-Sheet 5 Filed May 2, 1946 INVENTOR EDGAR R. WHITLEDGE ATTORNEYS Patented Jan. l, 1952 IMPACT TOOL Edgar R. Whitledge, Mantua, Ohio, assignor, by

mesneV assignments, to Reed Roller Bit Company, Houston, Tex., a corporation of Texas Application May 2, 1946, Serial No. 666,707 j 4 The present invention relates to impact clutches and tools and, more particularly, to portable, rotary, reversible, pressure fluid actuated tools, such as, wrenches, nut runners and the like.

One of the principal objects of the invention is the provision of a novel and improved impact clutch comprising a driving member having a relatively large moment of inertia and a driven member having a relatively7 small moment of inertia, and highly eicient, simple means for causing the driving member to deliver to the driven member a succession of torsional impulses far greater than the maximum torque of the driving mechanism.

Another of the principal objects of the invention is Athe provision of a novel and improved impact tool comprising a driving ilywheel or momentum member having a relatively large moment of inertia, that is, a relatively large mass offset a maximum distancefrom the center of rotation, and a driven anvil or member having a relatively small mass and moment of inertia,l in combination with highly ecient, simple means for causing the momentum member to deliver a successionof torsional impacts to the driven member.

Another of the objects oi the invention is the `provision of a novel and improved impact clutch comprising a rotatably supported, driven member or anvil having an external shoulder, a coaxially rotatabledriving member or iiywheel having a relatively large moment of inertia, and means including an impact member pivotally connected t the driving member for limited angular movement about an axis oiset from but parallel with the axis of rotation of the driven member and having a shoulder located adjacent to but adapted to trail the pivotal axis of the impact member with the driving member for causing the driving member to deliver to the driven member or anvil a succession of impacts.

Another obj ect of the invention is the provision of a novel and improved impact clutchand/or tool of the character referred to which is fully reversible.

The invention resides in certain constructions and combinations and arrangements of parts and further objects and arvantages thereof will be apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiment described with reference to the accompanying drawings forming .a part of thespecification in which 21 Claims. (Cl. 192-305) similar reference characters designate corresponding parts, and in which Fig. 1 is a side elevational view, with portions in section, approximately on the line I-I of Fig. 3, of a hand tool embodying the present invention;

Fig. 2 is a perspective view of a portion of the driving member of the impact clutch shown in Fig. 1;

Fig. 3 is a sectional view, approximately on the line 3--3 of Fig. 1, showing a relative position of the mechanism following impact;

Figs. 4, 5 and 6 are -views similar to Fig. 3, but showing the parts in positions which they occupy successively during the cycle of operation;

Fig. 7 is a view similar to Fig. 1, but showing a modied construction;

Fig. 8 is a sectional view, approximately on the line 8 8 of Fig. 7, showing a relative position of the mechanism following impact; and

Figs. 9, 10 and 1l are views similar to Fig. 8,. but showing the parts in positions which they occupy successively during the cycle of operations.

Although the invention is susceptible of general application and'may be embodied in various construction, it is herein shown and described "as embodied in a pressure uid actuated impact wrench. Except for the parts hereinafter specifically referred to, the tool shown may be of commercial construction and is not shown and described in detail.

Referring to the drawings, the tool shown is designated generally by the reference chai'- acter A and comprises a reversible motor, including a rotor l0, comprising radial vanes or blades Il slidably supported within suitable grooves formed in the rotor and through the medium of which the rotor is driven by pressure fluid, preferably compressed air, admitted thereto in a conventional manner by means including a trigger actuated valve, only the trigger l2 of which is shown in the drawings. Since the motor per se forms no part of the present invention, no further explanation is thought necessary other than pointing out that other motors, such as electric, may be employed, as desired.

In addition to the motor already referred to, the tool of the present invention comprises a driven member having a relatively small moment of inertia, a flywheel or driving member having a relatively large moment of inertia, and simple, eiiicient means for operatively connecting said members whereby the driving member is caused to .successively impact the driven member. In

the embodimentI shown, the driven member is in the form of a shaft I3 rotatably supported in a bushing VI4 xedly secured in the forward end of a clutch housing I5 detachably connected to the motor housing i6 by screws, not shown. The reversibility of the driving means may be under the control of a sleeve-type reversing valve il for directing 'the pressure fluid to either peripheral extremity of the conventional, lunate, expansible chamber surrounding the rotor IB. The forward end ofthe shaft I3 is provided with a driving connection adapted to have an adapter, not shown, applied theretoV but which, in turn, is adapted to engage a nut, bolt, Screw or other similar member which it is desired to tighten or remove. The rear or right-hand end of the shaft i3, as viewed in Fig. l, is of slightly greater di ameter and is provided with two axially spaced, diametrically arranged, 'i arcuately-shaped projections or anvils I8, I3 having radial sides 2U, 2i adapted to be impinged by radial surfaces on plate-like impact or

hammer members

22, 23 forming a part of the built-up flywheel or driving member or hammer assembly, designated generally by the reference character B. The anvils I3, I3 extend longitudinally of the shaft I3 and are impinged by the

impact members

22, 23, respecftively.

The

impact members

22, 23 have a relatively iarge, mass and are pivotally connected by p-

ins

24, 25 to an integral cage, designated generally by the reference character 26. The

pins

24, 25 are located diametrically opposite each other with respect to the axis of rotation of the driven member I3, which member is coaxially supported with respect to the driving or momentum member B and the rotor I0. The cage 23 comprises three

spaced disks

2l, 28 and 29 connected by relatively

narrow webs

33, 3l, 32,L 33 and the rear or right-hand end thereof, as viewed in Figs. l and 2, is keyed to the projecting spindle 34 of the rotor Iii. The Opposite or front end of the cage 26 is rotatably supported on the shaft I3 by a flanged bushing 35 of suitable wear-resisting material. Alternatively the cage may be of built-up construction.

The cage 26, as shown, is counterbored from the front end so as to permit the insertion of the anvil or rear endl of the driven member I3. The impact members 2,2 and 23 are arranged axially with respect to each other in the cage 23, the impact member 22 being located intermediate the disk portions 2l, 28 ofthe cage and the impact member 23 being located intermediate the

disk portions

23, 29 of the cage. The pin 24 is xedly secured in aligned apertures in the

disks

21, 28 of the cage. The disk 29 is provided with apertures 36 counterbored from the front end of the cage to a distance equal to the thickness of the disk 21 to form apertures as continuations of the apertures in the

disks

21, 28 within one pair of which the pin 24 is located. The impact member 23 is provided with an aperture 3l diametrically opposite the pin 25 and adapted to align with the apertures in the cage within which the pin 24 is positioned. This aperture, together with the aperture 33, provides an opening whereby the pin 24 may be driven out of the cage when it is desired to disassemble the impact member 22 for purpose of inspection or replacement. The radial flange 33 on the bushing 35 which overlies a portion of the aperture within which the pin 24 is located prevents axial movement of the pin toward the front of the cage in the event the pin becomes loose in the cage and the impact memi ber 23 prevents its movement in the opposite direction since the aperture 31 is of less diameter than the diameter of the pin 24.

The

impact members

22, 23 are similar in construction and the pin 25 is assembled in the cage 26 in a manner similar to that in which the pin 24 is assembled therein. The shoulder formed by the counterbcre in the disk 29 within which the pin 25 is located prevents movement of the pin toward the rear in the event it becomes loose in the cage and the impact member 22 prevents its movement toward the front. An aperture 39 inthe disk 22 similar to the aperture 31 in the disk 23 is provided so that the disks are interchangeable... thus facilitating manufacture, assembly and maintenance of the device. The counter-bore in the disk 29 in alignment with the pin 24 merely facilitates assembly.

The

impact members

22, 23 are narrower than the distance between the

webs

3S, 3l and 32, 33, respectively,v and the spaces between the disk-

like portions

21, 28, and 28, 23 within which the impact members are positioned are slightly greater than the thickness of the

members

22, 23, with the result that the

members

22, 23 are free to pivot between thel webs about the

pins

24, 25, respectively. The impact members 22,y 23 are symmetrical about central planes passingV through the centers of their pivotal axes and the apertures 33, 3l, respectively, and opposite sides thereof are provided with cut-out portions 43, 4I symmetrically arranged with respect to their pivotal connections with the cage 26. The cut-out portions 4Q, 4i are of such a character that they produce radial or substantially

radial shoulders

42, 43 on each impact member spaced from its pivotal connection with the cage 26. The

shoulders

42, 43 face the pivot for the impact member upon which they are formed and are adapted to engage the webs of the cage 26. The

shoulders

42, 43 of the impact member 23 are adapted to engage the

sides

44, 45 of the

webs

32, 33, respectively. The symmetrical construction of the cut-out portions 4U, 4I and the

shoulders

42, 43 Vwith respect to the pivotal axes of the impact members provides for reverse operation of the device, as will be hereinafter apparent.

The center of each impact member is provided with an` aperture 4l defined by arcuately-shaped, alternately arranged

surfaces

48, 49, 50, 5I connected by radial or substantially radial surfaces or

shoulders

52, 53, 54, 55. The arcuately-shaped surfaces 48, 4 3 are of equal radii as are the surfaces 50, 5Iv and all have their centers on a line connecting the centers of the pivot pin 23 and the aperture 31. The. surfaces 50, 5I have a common center and the. radii thereof are smaller than those of the. surfaces 48, 49, the centers of which are spaced apart to provide both the necessary clearance. for the anvil I9 and to provide ample size for the.

shoulders

52, 53, 54 and 55. Although the radii of the surfaces 50, 5I are smaller than the radii of the surfaces 4B. 49, they are soiicient to permit, the anvil associated therewith to rotate relative to the impact member when the member is swung to one side or the other about its pivotal connection with the cage 26. The construction of the

shoulders

42, 43 and the webs ci the cage 26 with which they engage is such that Vthe impact members may move a sufficient dis- -With which they cooperate.

The operation of both

impactmembers

22, 23

is alike, therefore, it will be sufficient to describe only the operation of the impact member 23. Assuming that the flywheel or momentum member B is rotating in a clockwise direction, as indil cated by the arrow R. the respective parts are shown in Fig. 3 in a position which they may occupy shortly after impact between the shoulder or surface 52 of the impact member 23 with the surface or shoulder 20 of the anvil I9. When the shoulder or surface 52 of the impact member struck or impacted the shoulder 20 of the anvil I3, see Fig. 6, the impact member 23 was rotated by the reaction produced, acting in the direction of the force arrow 60, in a clockwise direction about the pin 25 until the shoulder 42 struck the side 44 of the web 32. This movement of the impact member 23 allowed the shoulder 52 and the surface 50 to pass around the anvil I9. As the

shoulders

20, 52 disengage, the flywheel proper accelerates. member is preferably offset with respect to the axis of rotation of the clutch proper and the inertia of the impact member causes it to tend to lag behind the cage 23.

As soon as the surface 50 passes the rear end of the anvil I9 defined by the radial surface 2|, which it is about to do, as shown in Fig. 3, the impact member 23 will be free to rotate in a counterclockwise direction about the pin 25. At this time the flywheel proper is accelerating and driving the impact member 23 through the pin 25. The effect of inertia of the impact member 23, as previously mentioned, causes the member to lag .behind the flywheel proper whereupon the impact member will move from a position with the shoulder 42 in engagement with the web 32 shown in Fig. 3 to a position with the shoulder 43 in engagement with the web 33. The parts then will be in the approximate position shown in Fig. 5 and the surface 52 again in position to impinge the surface 20 of the anvil I9.

The method of operation just described is automatic but being subject to frictional drag between the parts, it is not positive, and to insure proper setting up of the impact member for the primary impact, the impact member 23 is provided with the internal radial surface or shoulder 54 which cooperates with the surface 20 on the anvil, if necessary, to assure proper resetting of the impact member. As shown in Fig. 3, the arcuately-shaped surface 50 is about to complete its passage over the anvil I9 and the radial surface 54 is approaching the impact surface 20 of the anvil and in the event the impact member 23 has not been reset by inertia, as explained before, and the shoulder 43 not in engagement with the web 33, by the time the shoulder 54 reaches the shoulder 2U, the shoulder 54 will impact or strike the shoulder 20, as indicated in Fig. 4. The anvil I 9 will offer resistance to rotation of the flywheel proper and will act against the shoulder 54 to rotate the impact member in a counterclockwise direction about the pin 25 until the shoulder 43 strikes the web 33. From the foregoing, it will be understood that the primary purpose of the shoulder 54 engaging the shoulder 20 is to assure proper setting of the impact member shoulder 52 into impact delivering position relative to the anvil shoulder 2B.

The force exerted by the anvil i3 against the member 23 will act in the direction indicated by the force arrow 6l and will have a moment arm of magnitude E2 about the center of the pin 25. As the member 23 rotates about the pin 25, the shoulders 20,154 Awill be disengaged andthe The center of mass of the impact arcuately-shaped surface 5I will be permitted to pass about the anvil I9, see Fig. 5, lwhereupon the flywheel continues to rotate freely until impact is made between the surfaces or

shoulders

20, 52, see Fig. 6. The condition existing when the shoulder 52 strikes the shoulder 20 is somewhat similar to that existing when the shoulder 54 strikes the shoulder 20 shown in Fig. 4 but the moment arm 63 of the impact force about the center of the pin 25 is much shorter than the moment 'arm 62, with thevvresult that the impact or blow delivered to the anvil I3 is considerably greater and has considerable force.

It will be noted that the power is transmitted to the impact member through the pivot pin 25 and that the shoulder 52 is adjacent to but trails the axis about which the impact member is pivoted to the driving member o'r flywheel proper. By varying the radial position of the pivot with respect to the shoulder 52, etc., or by varying theangular position of the shoulder 52 with respect to the pivot, the moment arm 53 can be increased or decreased to Vary the blow imparted to the anvil. The same is true of the shoulder 54 which,`as shown, leads the pivot for the impact member. When the shoulder 52 strikes the shoulder 20 of the anvil, the reaction pro-- duces a clockwise acceleration of the impact member 23 about the pin 25 which because of the relatively large mass of the impact member, adds to the fore of impact, moves the shoulder 42 into engagement with the surface 44 of the web 32, disengages the

shoulders

20, 52 and permits the'ywheel to resume rotation about the anvil. While the engaging

surface

52 and 54 on the impact member 23, and 2l) on the anvil i9, respectively, are preferably radial, they may be varied slightly from a true radial position so as'to facilitate their disengagement and eliminate all possibility of their hanging together, if desired.

The rotation of the impact member 23 about the pin 25 following impact between the shoulders 20,352 occurs with considerable acceleration and as the member 23 reaches its limit of movement by the shoulder 42 engaging or striking the web 32, the kinetic energy possessed by the impact member is transferred back to the rotating flywheel and serves to reduce the load of the flywheel upon thedriving motor, thus permitting the motor to accelerate and build up speed rapidly between successive impacts. When impact occurs between the

shoulders

20, 54 incident to setting up or preparing the impact member for the power or primary impact which takes place when the shoulder 52 strikes the shoulder 20, it occurs only because the frictional forces which may be present resist the automatic counterclocku wise movement of the impact member that would otherwise afford uninterrupted passage of the member about the anvil between successive primary impacts. The energy used in this setting-up impact is small, being much less than that imparted by the flywheel or hammer to the anvil upon impact between the

shoulders

20, 52 for the moment arm 52 at which the set-up force acts is much greater than the moment arm 53, and the direction of motion of the shoulder 54 is nearly collinear with the force arrow 6I, Whereas the direction of movement imparted to the 'shoulder 52 is almost perpendicular to the force arrow 50. Observation of the device in operation indicates that the impact member is frequently set up for the `power impact automatically. by the .inertia thereof, as previously explained,

.the surface or shoulder 2S cf the anvil i and without Contact. between the shoulders 20 54.. The anvils' i5, i9, and the. pivots for the im*

nactmembers

22, 23 are Offset 1.80 degrees. and. two power blows or impacts which act as a couple are @Heated 'upon each rotation ofthe vfis/wheel assembly E. Qbvouslv'anv number of impact members and anvils may beeniployed, inwhich event any desired number of impacts will be Obtained for each rotation of the iiywheel,

The anvils i9 and the

impact members

22, 23 are symmetrical with `respect to a central plane, from which 'it 'fellows that the clutch or operative connection betvvee'nthe driving inember B and the driven member i3 is reversible, therefore, it is only necessary to employ a reversible motor and 'the tool, iS suitable for tightening or locsening' nuts,'bclts, screws and the like. Referring tothe operation ci the 'impact member 23, when the drive is reversed the shoulders 2l, 53 and' correspond with the shoulders 2t, 52 and til,'respectively` With the exception of the driving element ci the clutch, the alternative construction shown in Figs. 7 to ll is similar to that already described and the duplicate parts are indicated by the'sa'me reference characters. As distinguished from the construction shown in Figs. l to 6 wherein the

impact members

22, 23 are pivotally supported in an integral cage 26, the impact members 55, d5 of the alternative construction are disk-like in form and are pivot-ally connected to diametrically arranged sleeves 67, 6d interposed between spaced plates lil, Il iixedly secured together so that they operate as a unit by bolts l2, '.'3 ex tending through the sleeves 6l, iid, respectively.

The plate li is keyed to the end 35 of the ro tor SG and the plate ill is rotatably supported by the shaft is. The sleeves 6l, 68 are slightly longer than the dish-like impact members 65, 6G, are thick, thus permitting each member tc move about the sleeve to which it is pivoted. Beth impact ineinbers G5, @E are alike and each is provided with an arcuateiy-shaped slot 'l through which the sleeves other than the sleeve to which the member is pivcted projects. The midpoint of each of the slots le is located lSc degrees from the axis about which the disk is pivoted, which axis' also forms the radial'ccnter of the slct.

ln the center of each disk there provided an aperture 'iii similar in configuration to theaper tures il? previously described'and dened by simi lar arcuately-shaped and radial surfaces deu signated by the same reference characters slots are of such length that the impact inem.- bers are permitted a limited movement about the sleeves upon which they pit'oted. which movement is suficientto cause the radial sin-u laces thereon to engage and disengage the radial surfaces of the'anvil with which they cooperate.

The operation of both

impact members

65, 35 is alike, therefore, it will be suicient to describe only the operation of the impact member B5. Assuming that the flywheel or momentum member B is rotating in the direction indicated by the arrowY R, the respective parts are shown in Fig. 8 in a position which they may occupy shortly after the primary impact between the shoulder or surface 52 of the impact member Sii with When the shoulder or surface 52 of the impact mem- 'ber struck or impacted the shoulder 23 of the anvil i8. see Fig. 11, the impact member was rotated by the reaction produced, acting in the Vdirection of" the vforce arrow til, in a clockwise direction. about-the sleeve `G'I--un-tilthe trailing accuser end of the slot 1 4 contacted the'sleeve 88. This movement of `the impact member 65 allowed the shoulder 52 andthe surface 50 to pass around the anvil i8. As the

shoulders

20, 52 disengage, the iiywheel proper accelerates. The center of mass of the impact member is offset with respect to the axis of rotation of the clutch proper and the inertia of the impact member causes it to tend to lag behind the flywheel proper.

As soon as the surface 50 passes the rear end of the anvil I8 defined by the radial surface 2i. which it is about to do,l as shown in Fig. 8, the impact member 65 will be free to rotate in a counterclockwise direction about the sleeve S1. At this time the flywheel proper Vis accelerating and driving the impact member through the sleeve El. TheV effect of the inertia of the irnpact member 65, as previously mentioned, causes the member to lagv behind the flywheel proper until the leading end of the slot 14 engages the sleeve 58, that is, the impact member B5' wi1 l move from the position shown in Fig.' 8 to the approximate position shown in Fig. l and the surface 52 will be in position to iinpinge the surface 20 of the anvil I8.

The foregoing method of operation is automatic but because of the variable fricticnal drag between the parts, it is not positive and to insure proper setting up of the impact member for the primary impact, the impact member E is provided with the internal radial surface or shoulder 5ft which cooperates with the Surface 2 0 on the anvil, if necessary, to assure proper resetting of the` impact member. As shown in Fig! 8., the arcuately-shaped surface 50 is about to complete its passage over`- the anvil i8 and the radial surface 54 is approaching the impact surface of the anvil and in the. event the impact. member 5.5 has notv been'reset by inertia,

as explained above, by the time the shoulder 51S reaches the shoulder 20, the shoulder 5,4 vwill impact or strike the shoulderV 23, as indicated in Fig. 9. The anvil I3 will offer resistance to rotation of the ywheel proper and will act ,f against theV shoulder 54 to rotate the vimpact member in a counter-clockwise direction about the sleeve El until the leading end of Vthe. slot lll' engages the sleeve 68.A

The force exerted by theanvil le against the member will act in the direction indicated by Vthe force arrow 6lv and willv have a moment. arm cf magnitude 62 about the center of the sleeve el. As the member E5 rotates4 about the sleeve 6 1, the shoulders 2,0, 54 will be disengaged and the arcuatelyeshaped surface 5 lr will be permitted to pass about, the anvil I8, see Fig. 10., whereupon the flywheel continues. to rotate freely until impact. is made between the4 surface or shoulders 2l), 52, see Fig. 1l. The condition` existing when the shoulder 5,2 strikes the shoulder 2,0

is similar to that existing whenfthe shoulder 54 strikes the shoulderY 2G shown in Figi 9, but the moment arm 63 of the impacty force about the center of the sleeve 671 is much shorter than the moment arm 62, with the result that the impart or blow delivered to the'anvil i8 is c on siderablyr greater and has considerable force.

When the shoulder 5K2` strikes the shoulder 2c of the anvil, the reaction produces. a clockwise acceleration of the impact member 65 about the sleeve 6lV which. because ofl the. relatively .large massv of the. impact member, adds to the force of impact, moves` the. trailing` end ofy the slot 'I4 into'. engagement. with the-sleeve 6 8; dis.- gengages; thel shoulders 2.0, 52` and` permits .the-fly,-

wheel to resume rotation about the anvil. While the engaging

surfaces

52 and 54 on theimpact member 65 and the surface 20 on the anvil I8, respectively, are preferably radial, they may be varied slightly from a true radial position Yso as to' facilitate their disengagement and eliminate all possibility of their hanging together, if desired. The shoulder 52, as shown, is adjacent to but trails the axis about which the impact member is pivoted to the driving member or iiywheel proper and the moment arm 63 can be increased or decreased to vary the blow imparted to the anvil by varying the relative radial position of the pivot with respect to the shoulder 52, etc., or by varying the relative angular position of the shoulder 52 with respect to the pivot. The same is true of the shoulder 54 which. as shown, leads the pivot for the impact member.

The rotation of the impact member 65 about the sleeve 51 following impact between the

shoulders

20, 52 occurs with considerable acceleration and as the opposite or trailing end' of the slot I4 strikes the sleeve 68, the kinetic energy possessed by the impact member is transferred back to the rotating flywheel and serves to reduce the load of the flywheel upon the drivingr motor, thus permitting the motor to accelerate and build up speed rapidly between successive impacts. When impact occurs between the

shoulders

20, 54 incident to setting up or preparing the impact member for the power or primary impact, it occurs only because the frictional forces which may be present resist the automatic, counterclockwise movement of the impact member that would otherwise afford uninterrupted passage of the member about the anvil between successive primary impacts. The energy used in this setting-up impact is small, being much less than that imparted by the flywheel or hammer to the anvil upon impact between the

shoulders

20, 52, for the moment arm 52 at which the set-up force acts is much greater than the moment arm 63, and the direction of motion of the shoulder 54 is nearly collinear with the force arrow E I, Whereas the direction of move ment imparted to the shoulder 52 is almost perpendicular to the force arrow 60. Observation of the device in operation indicates that the impact member is usually set up for the power impact automatically by the inertia thereof, as prev iously explained, and without contact between the

shoulders

20, 54. The anvils I8, I9 and the pivots for the

impact members

22, 23 are oiset I 80 degrees, and two power blows or impacts which` act as a couple are effected upon each rotation of the iiywheel assembly B. Obviously any number of impact members and anvils may be employed, in which event any desired number of impacts will be obtained for each rotation of the flywheel.

The anvils I8, I9 and the

impact members

65, 66 are symmetrical with respect to a central g plane, from which it follows that the clutch or From the foregoing description of the preferred embodiment of the invention, it will be apparent that a novel and improved impact tool has been in said aperture engageable with said anvil for' provided whereby an impact of considerable force can be applied to a nut, bolt, screw or the like by a relatively light tool. The tool shown is simple in construction, inexpensive to manufacture, will operate satisfactorily for long periods of time with minimum wear and replacement and produces a maximum torsional blow for a predetermined size and weight. While the preferred embodiment of the invention has been described in con siderable detail, the invention is not limited to the particular construction shown and it 'is my intention to hereby cover all adaptations., modi fications and uses thereof which come within the practice of those skilled in the art to which the invention relates and within the scope of the ap pended claims.

Having thus described my invention, I claim:

1. In an impact driving connection, the 'combination of a rotatably supported driven member having an anvil, a rota-table driving member coaxially supported with respect to said driven member, a hammer element pivotally connected to said driving member for rotation therewith and angular movement relative thereto about an axis offset from but parallel with the axis of rotation of said driving member, said hammer element having an impact shoulder located between said axes and positioned so as to always trail its pivotal connection, and movable into and out of the path of said anvil for delivering a succession of impacts thereto, automatic means for eifecting angular movement of said impact shoulder into the path of said anvil, and means responsive to the impact of said shoulder on the anvil for automatically effecting angular movement of said shoulder out of the path of said anvil in the same direction as that of said driving member.

2. In an impact driving connection, the combination of a rotatably supported driven member having an anvil, a rotatable driving member coaxially supported with respect to said driven member, a hammer element entirely surrounding said anvil and connected to said driving member for rotation therewith and pivotal movement relative thereto about an axis offset from but parallel with the axis of rotation of said driving member, the interior of said hammer element having a shoulder located between said axes and movable into and out of the path of said anvil by virtue of said pivotal movement for delivering a succession of impacts to `said anvil, automatic means for effecting pivotal movement of said shoulder into the path of said anvil, and :means responsive to the impact of said shoulder on the anvil for automatically effecting pivotal movement of said shoulder out of the path of the anvil.

3. In an'impact driving connection, the combination of a rotatably supported driven member having an anvil, a rotatable driving member coaxially supported with respect to said driven member, a hammer element connected to said driving member for rotation therewith and pivotal movement relative thereto about an axis offset from but parallel with the axis of rotation of said driving member, an aperture in said hammer element into which said anvil extends and pro# viding a first shoulder movable into and out of the path of said anvil by virtue of said pivotal movement for delivering a succession of impacts to said anvil, said first shoulder being moved out of the path of said anvil by virtue of its impact thereon, and means including a second shoulder moving said first shoulder into the path of said Aanvil.

4. An impact driving connection comprisingv a rotatablysupported. driven` member, a rotatable driving member coaxially supported with respect to said driven. member, acylindrical hammer carrier between said. members connected to4 said driv ing member for rotation therewith, an. anvil on said driven` memberand within said carrier, a hammer element pivotally connected. to said earrier for rotation therewith and pivotal movement relative thereto about an axis offset from but parallel with the axis of rotation ofv said carrier, an aperture in said hammer element into which said anvil extends and providing a shoulder movable into and out of the path of said anvil by virtue of` said pivotal movement. for delivering a succession of impacts to said anvil, automatic means for eiiecting pivotalr movement of said shoulder into the path of said anvil, and means responsive to the impact of said shoulder on the anvil for automatically eiectingV pivotal movement of said shoulder out of the path of theV anvil.

5. An impactI driving connection comprising a rotatably supported driven member, a rotatable driving member coa-Xially supported with respect toV said driven member, a cylindrical hammer car rier between said members connected' to said driving member for rota-tion therewith, a pair of axially spaced and diametrically opposed anvils on said driven member and within said carrier, a hol-low hammer element surrounding eachv anvil and pivotally connected to said carrier for rotation therewith and pivotal movement relative thereto, each hammer element having an internal shoulder movable into and out of the path of its respective anvil by virtue of said pivotal movement for delivering a succession of impacts to said anvil, and means in said carrier for limiting thel pivotal movement of said hammer element.

6*.y An impact driving connection comprising a rotatably supported dri-ven member having an.

ing the rotation of said hammer element for f automatically effecting pivotal movement of said hammer element, said means includingr a shoulder movable into and out of engagement. with said anvil by virtue of said pivotal movement for delivering a succession of impacts to said anvil.

'7. An impact driving connection comprising a rotatably supported driven Amember havingr an anvil, a rotatable driving member coaxially supported with respect to said driven member, a hammer element connected to said driving meniber for rotation therewith and pivotal movement relative thereto, an aperture in said element into which said` anvil extends, and means on the wall of said aperture adapted to engage said anvil during the rotation of said element for auto-r matically effecting its pivotal movement, said means including ashoulder movable into and out of engagement with said anvil by virtue ofk said pivotal movement for delivering a succession of impacts to said anvil.

8; An impact driving connection comprising a rotatably supported driven member having an anvil, a rotatable drivingmember coaxial-ly su1o-V ported with respect to said driven member, a

hammer element connected to said driving mme. f

lf2 ber for rotation: therewith. and pivotal movement relative thereto, an aperture in said. element. into which said anvil. extends, and. substantially dametrically opposed. internal shoulders on said 'element adapted. to engage said anvil during the rotation of saidelement. for automatically im partingv a succession of. rotary impacts to said anvil and effecting the pivotal movement of said element.

9. An impact driving connection according to claim 8 in which said internalshoulders are. lo cated one to trail and the other to leadV the connectionY between the hammer element and the driving memben l 10. AnY impact drivingconnection comprising' a rotatably supported. member' having an. anvil, a rotatable driving. member coaxially supported with respect to said driven member, a hammer element connectedto said driving memberV for rotation therewith and pivotal movement relative thereto, and a duality of substantially diamo-t# rically opposed shoulders on said elementvadapted toalternately strike said` anvil during normal rotation. of the. element whereby the striking shoulder is immediately shifted out off the path of thel anvil by virtuev of the impact and the ope posed shoulder is automatically moved into` the path of the anvil preparatory' to thenext impact 1l. An impact driving connection accordingI to'4 claim 10 in which. said internal' shoulders are: lo-n cated. one to trail and. the: other' to lead the corr4 nection between they hammer element andy the drivingv member. f

12. An impact driving connection cinpris'ing' a rotatably supported. driven'- member having an anvil, a rotatable. driving member coaXia-lly stip-f ported with respect to said driven' member, a

hammerelement connected to said driving member forrotation therewith and pivotal movementl relative thereto, and a duality of shoulders onv said. element adapted to alternatelystrike. said anvil. during normal rotation of the element, said anvil and shoulders having striking faces shaped and disposed relative to thexconnection between" the hammer element and the driving member whereby each impact automatically effects movement of the striking shoulder out of the path of the anvil 'and movement' of the other shoulder into the path. of the anvil preparatory to the next impact.

13. An impact driving connection comprising a. rotatably supported driven memberhaving an anvil, a rotatable driving member coaxially supported with respect to said driven member, a hammer element connected to said driving' member for rotation therewith and pivotal movement relative thereto, and means for effectingA the pivotal movement of said element including a striking shoulder and a resetting shoulder on said element one located on one side and the other one the other side of the connection between said element anddriving member, said shoulders being adapted to alternately strike said anvil during normal rotation ofthe element for impart1 ing a succession of rotary impacts to said anvil,

said striking shoulder being located closer to saidl connection than the resetting shoulder.

14. An impact driving connection according toclaim 13 in which lthe striking shoulder is located` to trail said connection.

15. An impact driving connection comprising nected to said-driving member for rotation there-` with in either direction and pivotal movement relative thereto, said element having two sets of two shoulders, one set of shoulders being adapted to engage said anvil during normal rotation of the element in one direction and the other set of shoulders being adapted to engage said anvil during normal rotation of the element in the other direction for automatically effecting its pivotal movement and imparting a succession of rotary impacts to said anvil.

16. An impact driving connection according to claim 15 in which the shoulders of each set are located one ahead and one behind the connection between said element and driving member with respect to the direction of rotation of said element.

17. An impact driving connection according to claim 15 in which the shoulders of each set are located one ahead and one behind the connection between said element and driving member with respect to the direction of rotation of said element, the shoulder of each set located behind said connection being closer thereto than the shoulder ahead thereof.

18. An impact driving connection comprising a rotatably supported driven member, a radially extending striking face on said member, a rotatable driving member, a hammer element, a connection between said driving member and element affording rotation of the element with the driving member and relative angular movement therebetween about an axis offset from but parallel with the axis of rotation of said driving member, said hammer element having a shoulder movable into and out of the path of said striking face by virtue of said angular movement for delivering a succession of impacts thereto, at the time of impact said shoulder being parallel with said striking face and located behind said connection with respect to the direction of rotation of said driving member, and interengaging means between said element and driven member automatically effecting angular movement of said shoulder into the path of said striking face, said shoulder being moved out of the path of said striking face by virtue of its impact thereon.

19. An impact driving connection comprising a driven element and a driving element rotatably supported on parallel axes, an aperture in said driving element into which said driven element extends, said driving element being capable of intermittent driving connection `with said driven element, and means in said aperture between said elements automatically eiecting and breaking said connection during each revolution of said driving element including a shoulder externally on said driven element and a shoulder internally on said driving element.

20. In an impact driving connection, the combination of a rotatably supported driven member having an anvil, a rotatable driving member coaxially supported with respect to said driven member, an impact member pivotally connected to said driving member for angular movement about an axis oilset from but parallel with the axis of rotation of said driven member, said impact member having a shoulder adapted to impact said anvil, said shoulder being arranged and disposed in a manner enabling a line normal thereto at the time of impact to pass through the pivotal con nection between the impact and driving members.

21. In an 'impact driving connection, the combination of a rotatably supported driven member having an external shoulder, a rotatable driving member coaxially supported with respect to said driven member, an impact member, a pin pivot ally connecting said impact member to said driving member for angular movement about an axis oiset from but parallel with the axis of rotation of said driven member, said impact member having a shoulder adapted to impact said shoulder on said driven member, said shoulder being disposed in a manner enabling a line normal thereto at the time of impact to pass through said pin.

EDGAR R. WHITLEDGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Richards Sept. 24, 1946