US2060054A - Draft and buffer gearing - Google Patents

Description

Nov. 10, 1936. G. E. EDMUNDS DRAFT AND BUFFER GEARING Original Filed July 27, 1934 3 Sheets-Sheet 1 Nov. 10,1936. G EDMUNDS DRAFT AND BUFFER GEARING Original Filed July 27, 1934 3 Sheets-Sheet 2 Nov. 10, 1936. ca. E. EDMUNDS DRAFT AND BUFFER GEARING' Original Filed July 27, 1934 3 Sheets-Sheet 3 551%??? f y M I 2 i i 7/ l I I I I I n, I

n? l 0 m 7 I \\\\\\\\\\\\\\\\A\\\\\ w Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE DRAFT AND BUFFER GEARING a corporation of Ohio Application July 27, 1934, Serial No. 737,301 Renewed September 4, 1936 17 Claims.

The present invention relates to draft gearing and to combined draft and buffer gearing for application to vehicle ends and while the invention is of general application, it is particularly well adapted for use in mine cars and in mine and industrial locomotives or the like.

In the accompanying drawings, I have shown practical embodiments of the invention and by way of illustration, I have shown combined draft and buffer gearing wherein a single set of springs serves to cushion both draft and buffing forces. Moreover, I have shown the gearing mounted in a housing or bracket to form a self-contained unit, the housing or bracket being designed to serve as the end sill of a mine car or the like. The invention, however, is not necessarily limited in these respects, the embodiments herein disclosed being merely illustrative and not restrictive of the invention whose scope is pointed out hereinafter in the claims.

In the drawings,

Figure l is a view substantially on the line i--I of Figure 2 of draft and buffer gearing embodying the invention;

Figure 2 is a front elevation of the gearing of Figure 1;

Figure 3 is a section substantially on the line 33 of Figure 1;

Figure 4 is a section substantially on the line 3- 1 of Figure 5 showing a modification of the arrangement of Figures 1 to 3;

Figure 5 is a horizontal section through one end of the gearing of Figure 4;

Figure '0 is a front elevation of a draft element appearing in Figures 1 to 4;

Figure 7 is a perspective of a draft transmitting element such as appears in Figures 1 and 3 and in slightly modified form in Figures 4 and 5;

Figure 8 is a view substantially on line 88 of Figure 9 of another embodiment of the invention;

Figure 9 is a View substantially on line 9-9 of Figure l; and

Figure 10 is a section on line 10-40 of Figure 8.

Referring first to Figures 1 to 3, 6 and 7, reference numeral [5 designates generally a housing or bracket which also may constitute the end transverse member or sill of a car such as a mine car. The housing comprises a rear wall l6 whose end portions have forward faces in a substantially vertical plane. Arms H and I8 project rearwardly of wall [6 at the ends of the latter and are adapted to be secured to the ends of the longitudinal members or sills of a car such as a mine car, The rear wall L6 h yfi 3. .rearwardly offset central portion lfia in a vertical plane parallel to the end portions of wall l5 and joined with the same by means of parallel vertical wall portions I9 and 20. Spaced inwardly of wall portions l9 and 20 are a pair of parallel vertical webs 2| and 5 22 whose forward edges line in the plane of the forward faces of the end portions of wall l6. Webs 2| and 22 terminate upwardly a distance below the upward extremity of wall portion a as may be seen in Figure 3. Wall portions 19 and 20 and 10 webs 2! and 22 define a pair of forwardly faced pockets 23 and 24.

Projecting forwardly from the top of wall l6 are a pair of horizontal walls 25 and 26 between which and centrally of the housing is an opening 15 bounded by the parallel edges 25' and 26 which, as clearly shown in Figure 2, are provided. with rabbets or undercut recesses A continuous wall 27 parallel to walls 25 and 26 projects forwardly from the lower edge of the wall 16 and is extended 20 rearwardly to wall portions [6a to provide a bottom 21 for the pockets 23 and 24. The forward portion 2? is dropped slightly relative to the rearward portion 21 as shown in Figure 3. A wall portion 28 connects walls I9, 20 and Mia and pro- 25 vides cover portions for the pockets 23 and 24. The lower surface of wall portion 28 is in about the same horizontal plane as the lower surfaces of the adjacent relieved marginal portions of walls 25 and 26. outwardly the rear wall may be re- 30 inforced by gussets as at 29 and 30, Figure 1. The housing may be provided in the plane of wall IS with upward projections 31 adapted to be riveted to the contiguous end wall of a car.

At their outer extremities, walls 25 and 26 are joined with wall 21 by means of webs Ila. and 58a forming forward extensions of arms I! and I8. Inwardly of these latter webs walls 25 and 26 are joined with wall 21 by means of the vertical parallel webs 32 and 33 which may extend out to the forward edges of the connected walls. Spaced inwardly from webs 32 and 33 and projecting a short distance forwardly of Wall 16, is a pair of parallel vertical webs 34 and 35.

While not necessarily so, the entire housing structure just described is preferably formed as a single casting preferably of steel.

A buffer element or bumper generally designated by the reference numeral 36 has a horizontally curved front wall 31 providing a bufling face and has a substantially rectilinear rear face 38 rearwardly of which project a series of symmetrically spaced spring centering bosses 39'. While I have shown four of these bosses for the accommodation of the ends of four coil springs 40, it will be understood that the number may be varied in accordance with the spring requirement.

Top and bottom walls ll and 42 project rearwardly from the front wall of the buffer element and are so spaced apart as to be slidably receivable between the top and bottom walls of the housing. The ends of the front wall and bumper are turned rearwardly to provide laterally thickened portions 43 and 44 which are provided with longitudinally elongated slots 45 and 46 which are forwardly enlarged, as shown in Figure l. The portions 43 and 44 are spaced apart so as to be positionable between webs 32, 34 and 33, 35 respectively. Walls 25 and 2'! are provided with vertically aligned openings registering with the slot 45 and a connecting pin l? is passed through all three. A similar pin 48 is passed through vertically aligned openings in walls 26 and 27 and the slot 45. Normally the buffer element is in the position shown in Figure l, wherein pins 4'! and 48 engage the rear ends of slots 45 and 46.

The shape of portions 43 and 44 of the buffer element is such that they will not interfere with the forwardly projecting vertical webs 32, 34 and 33, 35 when the buffer element moves translationally or pivots about one or the other of pins 41 and 48, such pivoting being permitted due to the forward enlargement of slots 55 and 4G. The rear portions of these slots have a diameter su stantially that of pins 4? and 48 so that when the buffer element is in the normal forward position shown in Figure 1 it is properly centered. Inward movement of the buffer element is limited through contact of the inner ends of portions 43 and 44 with the rear housing wall 65. The top and bottom walls 41 and 42 of the buffing element have their rear edges somewhat forward of the rear ends of portions t3 and 44 so as to permit the latter to move against wall l G without interference between the rear edges of walls 41 and 42 and the forward edges of webs 34 and 35.

To the rear of the buffer element is disposed a horizontally extending channel member as which will be referred to hereinafter also as a follower and as a drawbar. Member 59 has a vertical web 49 which normally lies against the front face of housing wall l6 and the forward edges of webs 2i and 22 and extends between the webs 34 and 35 to be positioned thereby. Member .9 also has upper and lower flanges 53 and M which lie substantially in the planes of the top and bottom walls 4! and 42 of the buffer element and are similarly slidable between the top and bottom walls of the housing. Flanges 5t and 55 have a limited forward projection so as not to interfere with full rearward movement of the buffer element. Their forward projection may be such, however, that the rear edges of walls 4i and 52 of the buffer element, upon rearward movement of the latter, will contact therewith simultaneously with the contact of portions 43 and 44 with wall I 6, so that limiting abutment means for the buffer element will be provided throughout the width of the latter. At its ends, member 49 has forwardly projecting parallel arms 52 and 53 of such vertical extent and of such length as to be guided between the top and bottom walls of the buffer element so that straight line movement of member 49 is enforced.

Formed on the inner face of member 49 are four centering bosses 54 in alignment with the bosses 39 of the buffer element, the springs 48 having their ends engaged by opposite ones of the bosses. Springs 43 are compression springs and normally hold the parts in the position shown in the drawings wherein members 39 and 36 are in maximum spaced relation. Under buff the springs permit rearward movement of the buffer element to the limit position already described, while under draft member 49 may move forwardly until the forward edges of its flanges 58 and El abut the rear edges of walls 4! and 42 of the buffer element.

A draft element generally designated by the reference numeral 55 has a bottom plate portion having parallel lateral edges recessed complementarily to the edges 25' and 26 so as to be slidably guided between the latter and held against upward displacement by the latter. The plate 56 is slidably supported on the top wall 4! of the bufiing element, on the top flange 50 of member 2-8. Plate 56 has a downwardly relieved tail portion 56a which is received beneath wall portion 28 of the housing and on the upper ends of webs 2! and 22. Projecting downwardly from the portion 55a and positioned in the upper ends of pockets 23 and 24 is a pair of lugs or ears 5] and 58, Figures 1, 2 and 6. Forwardly of wall portion 28 of the housing, plate 58 supports a tongue having a forward projecting upwardly spaced horizontal portion 59. Plate 56 and tongue 59 are provided with vertically aligned apertures 50 and 64 which are adapted to receive a coupling pin an elongated slot 63 being provided in the top wall 4! of the buffer element to provide clearance for the lower end of the pin so that there will be no interference with the same in all relative positions of the draft and buffer elements.

Lugs 57 and 58 are pierced to receive pins E i and 65 which support a pair of double faced cams 66 and 5. in the pockets 2?. and fi l, each cam, as shown in Figure '7, having a bifurcation in which the respective lug received and each cam being pierced as at 68 to receive its respective pin. The two cams are of identical form and a. description of cam 6? which appears in profile in Figure 3 will sufiice for both, cam 67 also being assumed to be shown in Figure '7.

The cam 6'5 has a normal rocking axis substantially at 2:, Figures 3 and 7, an upper forward cam surface and a lower rearward cam surface Til, the cam being fundamentally of the 8 type. Above the surface '19, the cam has a substantially plane surface which normally lies close to or in contact with the front face of wall portion lea and the cam is of such thickness that its forward extremity is normally closely adjacent to or in contact with the rear surface of follower 49.

Upon application of draft through the draft member 55 the latter moves forwardly carrying therewith pin 55 and rocking cam about its axis 0:. Under these conditions, the axis a: is carried forward by reason of the action of the cam surface on the abutment wall 560. and also, theoretically, the axis x will vary somewhat in vertical position due to the fact that the cam rotates about pin 65 which moves strictly horizontally with the draft element. As the cam is rocked the cam surface 59 rides on the follower. Consequently, the follower is moved forward not only as a result of the direct camming action of the surface 69, but also as a result of the bodily displacement or translatory movement of the upper portion of the cam due to the action of the cam surface 78 on its fixed abutment. The curves of the cam surfaces are so chosen that the forward movement of the follower will be substantially less and preferably about half of the inducing movement of the draft element. That is to say, there is a substantial reduction in movement of the follower as compared to the movement of the draft element under draft, so that in compressing the springs 40 the draft element has a substantial mechanical advantage Wer the buffer element whose action is direct. Thus, while the same set of springs is used both under draft and under buff, its effective resistance to compression is much greater under buff. In designing the cams for the attainment of the desired relation, it is to be borne in mind that appreciable frictional resistance is encountered under draft due to the fact that the cam surfaces of the cams must slide both on the abutment. and follower. It will be seen from Figure 1, that laterally the cams substantially fill the pockets and that the suspension pins are retained in position merely by the adjacent side walls of the pockets, no special fastening means being required.

The cams 6E and 61 are disposed symmetrically relative to the follower or drawbar and exert a balanced action on the latter. Due also to the guiding effect of arms 52 and 53, a straight line movement of the follower on the axes of the springs is enforced.

Outward or forward movement of the draft element is limited as a result of limitation of forward movement of the follower or drawbar. Inward or rearward movement of the draft element is limited positively through abutment of portion with wall Ilia.

In assembling the above described apparatus the draft element and suspended cams are first moved to position in the housing and held thus since until the buffer element and follower are in position, there is no support for the weight of the draft element. The follower and buffer element, being assembled together with the springs between them, are now moved into the housing beneath the draft element and are forced rearwardly until pins 41 and 48 can be dropped into position and fastened, thus completing the assembly.

In Figures 4 and 5, I have shown a modification according to which strict horizontal bodily movement of the cam 61' is enforced. In this case, the cam 61' is provided with a bore coincident with its rocking axis, this bore receiving a pin ii which projects beyond each side of the cam to provide trunnion portions. Furthermore, the apertures 68 which receive the pin 65 are slightly vertically elongated in order to give a somewhat loose pivotal connection with the draft element. The side walls 20 and 22 of the pocket 24 are provided with parallel horizontal grooves 12 and 13 which extend through to the front edges of the pocket side walls which are preferably thickened as at M and '55 to accommodate the grooves. The trurmion portions have a close sliding fit in the horizontal guideways l2 and 13, so that strictly horizontal movement of the rocking axis of the cam is enforced. Free swinging of the cam is permitted by the enlarged apertures 68, as will be understood. Essentially, the operation is the same as that heretofore described.

With respect to Figures 4 and 5, the manner of assembly is the same as described above, the only difference being that the pins H must be inserted in the cams and guided to position in the slots '52 and it when the draft element is inserted.

In Figures 8, 9 and 10 are shown the same housing IS, the same draft element 55 and the same cams 6B and 61 as in Figures 1 to 3, 6 and 7,

different follower and buffing elements being provided with coacting friction faces.

Referring to Figures 8 to 10, the buffing element [6 is of generally similar form to that previously described, but differs in being provided between its top and bottom walls fl and 18 with relatively obtusely forwardly converged friction faces 19 and 8!), these faces preferably lying in vertical planes. A follower member 8i comprises an elongated horizontally arranged channel member having a vertically disposed web 82 normally lying against the abutment faces of the housing. Member 8| has top and bottom flanges 33 and 84 which centrally are interrupted to provide a forwardly open recess 85 which provides clearance for the lower end of the coupling pin. At either side of recesses 85, the edges of the top and bottom flanges are joined by vertical webs 86 and 8'! whose outer faces are provided with spring centering bosses 88. Flanges 83 and 84 are spaced apart so as to be slidably receivable between the top and bottom walls I! and '58 of the buffer element and at their outer ends are curved away as at 89, Figure 8, so as to provide adequate clearance for relative movement as regards the wedge surfaces 19 and 80 of the buffer element. Wedges or shoes 99 and SI are carried between the webs 83 and 84 at their outer ends and have faces in frictional engagement with the friction faces 19 and 8B of the buffer element. Each shoe, as most clearly shown at the right of Figure 8, is provided with spring centering bosses 92 opposite the bosses 88 and compression springs 93 are engaged therebetween, so that the friction faces of the shoes and the buffer element are operatively forced together. The bases of the shoes lie against the rear web 82 of the follower, this rear web being engaged rearwardly by the cams which may be of either design heretofore d cribed although the cams 66 and 67 are specifically shown.

The action of the cams is exactly the same as heretofore described. Upon relative movement as regards the follower and buffer element. shoes 90 and 9! are forced together to compress the springs 93, the relative movement being resisted by the coacting friction surfaces which, of course, include the contacting surfaces of the shoes and web 82 of the follower. Rearward movement of the buffer element is positively limited in a manner heretofore described, forward movement of the follower being positively limited, if required, through abutment of the forward edges of its horizontal webs with the adjacent surfaces of the buffer element. Straight line movement of the follower is secured as before.

In assembly the draft element together with the cams are first inserted to position and held. The follower with the wedges assembled therewith then inserted as far as possible in the buffer element and the latter is then inserted in the housing and forced rearwardly until the retaining pins can be dropped in position.

As above stated, the housing i5 is preferably an integral steel casting. Also, preferably, the buffer, draft, and follower elements are each formed as an integral steel casting, although not necessarily so. In each case rearward movement of buffer means is preferably positively limited before impact can reach the forward edge of the draft element It will be noted from Figure 3 that the buffer element has a lower lip projecting in front of the lower housing wall 21.

From the above description it will be evident that the invention may be variously embodied as to form an arrangement of the essential elements. While the invention is particularly effective in combined draft and buffer gearing of the type utilizing a single set of springs, due to the differential action of the springs which is obtained, it will be understood that the described draft arrangement may be used without relation to any particular buffing apparatus. Accordingly, I do not limit myself except as in the following claims.

I claim:

1. Apparatus of the class described comprising a draft element supported for reciprocation in a horizontal plane, a cam member having a cam surface faced in the direction of draft application, a downwardly projecting lug on said draft element pivotally engaged with the upper part of said cam member, a follower for engagement by said cam surface, means preventing movement of said cam member away from said follower, yieldable means arranged to oppose movement of said follower under the action of said cam surface of said cam member when draft is applied to said draft element, and means limiting the range of movement of said follower.

2, Apparatus of the class described comprising a draft element supported for reciprocation in a horizontal plane, a cam member having front and rear cam surfaces. 2. downwardly projecting lug on said draft member pivotally engaged with said cam member whereby said cam member is rocked upon movement of said draft element under draft, a fixed abutment engaged by said rear cam surface and a follower engaged by said front cam surface when said cam portion is rocked under draft whereby the follower is moved both as a result of the direct action of said front cam surface and as a result of translatory movement of that portion of the cam member engaged therewith as enforced by the rear cam surface in its coaction with said abutment, yieldable means arranged to oppose such movement of said follower, and means limiting the range of movement of said follower.

3, Apparatus of the class described comprising a draft element supported for reciprocation in a horizontal plane, a cam member having front and rear cam surfaces, a downwardly projecting lug on said draft member loosely pivotally en- {raged with said cam member whereby said cam member is rocked upon movement of said draft element under draft, a fixed abutment engaged by said rear cam surface and a follower engaged by said front cam surface when said cam portion is rocked under draft whereby the follower is moved both as a result of the direct action of said front cam surface and as a result of translatory movement of that portion of the cam member engaged therewith as enforced by the rear cam surface in its coaction with said abutment. means constraining the rocking axis of said cam portion to displacement in a horizontal plane, yieldable means arranged to oppose such movement of said follower, and means limiting the range of movement of said follower.

4. Apparatus of the class described comprising a draft element supported for reciprocation in a horizontal plane, a cam member having front and rear cam surfaces, a downwardly projecting lug on said draft member loosely pivotally engaged with said cam member whereby said cam member is rocked upon movement of said draft element under draft, laterally projecting t nion portions on the rocking axis of d cam member, means providing horizontal guideways in which said trunnion portions are guided, a fixed abutment engaged by said rear cam surface and a follower engaged by said front cam surface when said cam member is rocked under draft whereby the follower is moved both as a result of the direct action of said front cam surface and as a result of translatory movement of that portion of the cam member engaged therewith as enforced by the rear cam surface in its coaction with said abutment, yieldable means arranged to oppose such movement of said follower, and means limiting the range of movement of said follower.

5. Apparatus of the class described comprising an end transverse structural ear member having a forward face in a vertical plane and at least one rearwardly offset portion providing a pocket to the rear of said front face, a draft element sup ported to the front of said transverse member for movement toward and away from said member, a cam member disposed in said pocket and operatively related to said draft element to be rocked thereby upon application of draft thereto, a follower member for said cam member arranged in front of the latter, yieldable means arranged to oppose movement of said follower member by said cam member upon application of draft to said draft element, and means limiting the range of movement of said follower.

6. Apparatus of the class described comprising an end transverse structural ear member having a forward face in a vertical plane and at least one rearwardly offset portion providing a pocket to the rear of said front face, a draft element supported to the front of said transverse member for movement toward and away from said member, a cam member disposed in said pocket, said cam member having front and rear cam surfaces, a downwardly projecting lug on said draft member loosely pivotally engaged with said cam member whereby said cam member is rocked upon movement of said draft element imder draft, trunnion portions projecting laterally of said cam member at the rocking axis of the latter, said rearward offset providing side bounding walls for the pocket, said walls having horizontal guideways therein in which said trunnion portions are guided, said offset providing a rear wall for the pocket engaged by said rear cam surface upon rocking of said cam member, a follower engaged by said front cam surface when said cam member is rocked under draft, whereby the follower is moved both as a result of the direct action of said front cam surface and as a result of translatory movement of that portion of the cam member engaged therewith as enforced by the rear cam surface in its coaction with said abutment, yieldable means arranged to oppose such movement of said follower, and means limiting the range of movement of said follower.

7. Apparatus of the class described comprising a housing securable to a car end in transverse relation, said housing having a rear wall and outwardly extending top and bottom walls, a buffer element having top and bottom walls slidably received between the top and bottom walls of said housing, a drawbar between said bu r element and the rear wall of said housing, said drawbar having surfaces slidably guidable between the able means, a draft element, and means for transmitting movement of said draft element under draft to said drawbar, said last named means comprising a cam member interposed between said drawbar and the rear wall of the housing.

8. Apparatus of the class described comprising a housing securable to a car end in transverse relation, said housing having a rear wall and outwardly extending top and bottom walls, a buffer element having top and bottom walls slidably received between the top and bottom walls of said housing, a drawbar between said bufier element and the rear wall of said housing, said drawbar having surfaces slidably guidable between the top and bottom walls of said buffer element, yieldable means interposed between said buffer element and said drawbar, means limiting the movement of said buffer element and drawbar away from each other under the influence of said yieldable means, a draft element, and means for transmitting movement of said draft element under draft to said drawbar, said last named means ineluding a cam member between said drawbar and the rear wall of said housing and having portions bearing against said drawbar and the rear wall of the housing respectively when draft is applied to said draft element.

9. Apparatus of the class described comprising a draft element supported for reciprocation, a cam member operatively related to said draft element to be rocked thereby upon application of draft thereto, a follower for said cam member, a buffer element, a compression spring arranged on a horizontal axis between said follower and said buffer element to oppose movement of said follower induced by said draft element and to oppose movement of said buffer element under buff, means guiding said follower for straight line horizontal movement, and means limiting the range of movement of said follower.

10. Apparatus of the class described comprising a buffer element having at its rear side forwardly convergent friction faces, a drawbar behind said buffer element, said drawbar being substantially in the form of a channel with its flanges projecting toward said buffer element, shoes slidable in the ends of said channel, means yieldingly forcing faces of said shoes into frictional engagement with said convergent friction faces, means limiting movement of said buffer element and drawbar apart, and means for transmitting draft to said drawbar comprising a cam member for which said drawbar is a follower.

11. Apparatus of the class described comprising a buffer element having at its rear side forwardly convergent friction faces, a drawbar behind said buffer element, said drawbar being substantially in the form of a channel with its flanges projecting toward said buffer element, said flanges being interrupted centrally to provide clearance for a coupling pin, the channel having abutments at the sides of the flange interruption faced toward its ends, shoes slidable in the ends of said channel, yieldable means between the respective abutments and shoes forcing faces of the latter into engagement with said convergent friction faces, means limiting movement of said buffer element and drawbar apart, and means for transmitting draft to said drawbar.

12. Apparatus of the class described comprising a buffer element having at its rear side forwardly convergent friction faces, a drawbar behind said buffer element, said drawbar being substantially in the form of a channel with its flanges projecting toward said buffer element, said flanges being interrupted centrally to provide clearance for a coupling pin, the channel having abutments at the sides of the flange interruption faced toward its ends, shoes slidable in the ends of said channel, yieldable means between the respective abutments and shoes forcing faces of the latter into engagement with said convergent friction faces, means limiting movement of said buffer element and drawbar apart, and means for transmitting draft to said drawbar comprising a cam member for which said drawbar is a follower.

13. Apparatus of the class described comprising a draft element supported for reciprocation, a cam member operatively pivotedto said draft element, said cam member having front and rear cam surfaces, a fixed abutment engaged by the rear cam surface and a follower engaged by the front cam surface when said cam member is rocked under draft whereby the follower is moved both as a result of the direct actionof the front cam surface and as a result of translatory movement of that portion of the cam member engaged therewith as enforced by the rear cam surface in its coaction with said abutment, yieldable means arranged to oppose such movement of said follower, and means limiting the range of movement of said follower.

14. Apparatus of the class described comprising a draft element supported for reciprocation, a cam member operatively pivoted to said draft element, a fixed abutment and a follower between which said cam member is disposed, said cam member having a front cam surface adjacent its pivoted end for co-operation with said follower and a rear cam surface adjacent its other end for cooperation with said abutment, a buffer element, and yieldable means between said follower and said buffer element.

15. Apparatus according to claim 14 wherein the cam member depends from the draft element.

16. Apparatus of the class described comprising a draft element supported for reciprocation, a follower and a fixed wall in parallel relation and extending horizontally transversely of the line of draft application, a pair of cam members pivotally suspended from said draft element and positioned between said wall and said follower, said cam members upon the application of draft to said draft member cooperating with said fixed wall and with said follower, said cam members being arranged relative to the follower so as to exert a balanced action thereon, a buffer element extending in front of said follower, and yieldable means between the follower and buffer element.

17. Apparatus according to claim 16 wherein the cam members are disposed in pockets in said fixed wall.

GLENN E. EDMUNDS.

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