US2092949A - Draft rigging - Google Patents

Description

D. S. BARROWS DRAFT RIGGING Sept. 14, 1937.

Filed April 22. 1930 2 Sheets-Sheet l Se t. 14, 1937. D. s. BARROWS DRAFT RIGGING 2 Shets-Sheet 2 Filed April 22. 1930 Patented Sept. 14, 1937 UNITED STATES DRAFT RIGGING Donald S. Barrows, Rochester, N. Y., assignor to The Symington-Gould Corporation, Rochester, N. Y., a corporation of Maryland Application April 22, 1930, Serial No. 446,334

17 Claims. (Cl. 21322) This invention relates to railway draft rigging, and draft gears or friction shock absorbing mechanism associated therewith, whereby a greater travel of the associated coupler is permitted under bufiing than under draft, the greater bufling movement being resisted by a shock absorbing capacity greater than interposed to draft movement.

The principal object of my invention, generally considered, is to provide, in combination with a car underframe, a friction draft gear comprising parts operating in series with respect to a column or housing member, which preferably encloses the same and is provided with an intermediate shouldered portion or slot for receiving intermediate stop means, so that the mechanism will function to provide a greater energy-absorbing capacity for buffing forces than for draft forces.

Another object of my invention is to provide draft rigging involving a drawbar suitably connected to a vertic-alyoke which, in turn, embraces friction shock absorbing mechanism which is adapted to resist movement of the drawbar under both bufiing and draft, the underframe, and particularly the draft sills thereofybeing provided with intermediate stop means for preventing forward movement of the housing or outer member of the cushioning mechanism, whereby only part of the capacity thereof is utilized for absorbing draft forces, while all of the capacity is brought into play for the absorption of buffing forces.

A further object of my invention is the provision of a double-ended friction draft gear involving a housing open at both ends for receiving friction elements and associated resilient means, the intermediate portion of said housing being shouldered or slotted for cooperation with intermediate stop means on associated sills whereby the friction mechanism at one end of the housing only may be utilized for the cushioning of draft forces while the mechanism at both ends is available for the cushioning of buffing forces.

Other objects and advantages of the invention relating to the particular arrangement and construction of the various parts will become apparent as the description proceeds.

Referring to the drawings illustrating my invention, the scope whereof is defined by the appended c1aims:

Figure 1 is a horizontal sectional view through the draft sills of a railway vehicle underframe illustrating one embodiment of my double ended series draft gear or cushioning mechanism with associated draft rigging and stop means, the

draft gear and associated yoke being shown partly in plan and partlybroken away to more clearly illustrate the construction.

Figure 2 is a vertical sectional view illustrating the embodiment of my gear and associated rig- 5 ging shown in Figure 1, a portion of the associated yoke being brokenpaway to more clearly show the construction. a

Figure 3 is a view corresponding to Figurel, but showing a modification. Figure 4 is a fragmentary View corresponding to Figure 2, but further illustrating the modification shown in Figure 3.

Figure 5 is a transverse sectional view on the 1 line 5-5 of Figure 4, looking in thedirection of the arrows.

On account of the present day weight of, and

speed atwhich railway rolling stock is moved,

the limits within which the accompanying energy can be absorbed have passed beyond the conventional draft gear travel regardless of the capacity thereof. It will be understood that in a draft gear for absorbing large amounts of energy it is desirable that the capacitythereof be greater on buff than under the action of draft forces, because it is under buff that the greater amount of energy is necessarily absorbed. It is also desirable, for the same reason, that the distance the coupler or draw bar and the associated draft gear or cushioning mechanism parts move in absorbing such kinetic energy be greater under the action of buffing forces than under the action of draft forces in order that the slack to be taken up in starting a. train is maintained relatively low, while at the same time provision is made for absorbing the requisite energy without exerting too great a resisting force, in order to obviate damage to the rolling stock.

The conventional draft gear travel at the present time is ample for, the absorption of draft forces, but a gear or cushioning mechanism of high enough capacity to seem to absorb the normal buffing shock is too "high in capacity to handle pulling shocks without unduly stressing the coupler and attachments. characteristics of a draft gear have been found to be moderate travel and capacity under pull and at least twice the travel and capacity for energy absorption under buff.

In accordance with my invention, I accomplish the desired result heretoforedescribed by using a single draft gear'comprising a column member, shell or housing preferably open at both ends and provided with shouldered or slotted portions adjacent the central part thereof for-co- The desirable 45 v gear.

operation with intermediate stop means connected to the associated draft or center sills, said column member having friction elements at both ends, the elements at one end only being operated on draft and the elements at both ends being operated on buff.

Referring now to the drawings in detail, like parts being designated by like reference characters, and first considering the embodiment of my invention illustrated in Figures 1 and 2, there are shown portions of a railway vehicle underframe comprising center or draft sills I connected by a.

casting 2 and a striking casting or end member (not shown) at the ends thereof.

The sills l are slotted, as is usual, forreceiving a draft key for connection with associated draft rigging and preferably have connected thereto:

cheek plates or front draft stops or lugs 3 slotted at 4 with the slotted portions therein preferably reinforced by flanges 5 -for rigidifying the edges of said members adjacent said slots fortheproper transmission of large forces. In the present embodiment, I employ the draft lugs 3 with front stopportions or shoulders 6 spaced rearwardly from the normal position of the rear edge of the key I so as to permit said key tomove rearwardly an amount necessary to completely close the associated draft gear or cushioning mechanism 8 which is mounted between the sills I.

In the present embodiment, the draft gear 8 is double ended or double acting and supported between the sills in any desired manner, as on the lower portion of-the associated vertical yoke 9 Which,in turn, may be supported in any desired manner, as by means of carry irons (not shown). Said gear desirably comprises acolumn member or housing Ill open at front and rear ends and provided intermediate said ends with a shouldered portion l l or abutment surfaces for normally engaging cooperative abutment surfaces on means, such as intermediate draft lugs l2 desirably connected to the sills I as by means of rivets l3, for the transmission of draft-mechanism -affecting forces, thereby being front stop means for said Each end of the housing or shell I .is preferably formed double bell mouthed, that is, it is provided with sloping walls l4 providing outermost flar ing or inclined friction surfaces l and inwardly disposed, but preferably correspondingly inclined,

friction surfaces l6 with a shouldered portion ll therebetween. Cooperating with the frictionsurfaces and shouldered portions on the. shell or housing Ill are-both front and rear friction shoes or wedges l8 provided with correspondingly inclined friction surfaces l9 and 20 engaging the friction surfaces l5 and IS on. the shell and provided with a shouldered portion 2| therebetween for cooperating with the correspondingly shou1-. dered portion IT on the housing and limiting outward movement of said friction elements I8 with respect to the housing when assembled therewith.

,In order to urge the friction elements l8 into engagement with the friction surfaces on the housing l0, resilient means 22 preferably in the form-ofcurvedleaf springs, are provided between the friction elements at each end of the housing. Said leaf springs at each end preferably involve two .sets,;bowed or curved concavely toward the adjacent friction-elements l8. -In order to preventshifting of the springs with respect to the friction elements l8, saidelements are desirably formed with shouldered portions 23 at the inner endsthereof, theouterends of saidsprings being retained in position by the respective followers 24 and 25.

The draft gear 8 is connected to the butt or draw bar 26 of the associated coupler 2'! in a usual manner, as by means of the hooded vertical yoke 9 embracing the gear 8 with its hooded front end connected to the shank 25 of the coupler the horizontal key 1 extending through the registering slots in the coupler shank and yoke, or front socketed portion of the latter, and'with its ends received in the slots or apertures 4 in the front draft lugs or cheek plates 3. It will be clear that back stop or combined back stop and center filler Y while the rearward elongation of the slots 4 in the lugs 3 is necessarily sumcient to permit full compression of the gear with both front and rear followers in engagement with the corresponding the housing or shell 8 is stopped against forward movement by the lugs H, as previously explained. Although Ihave illustrated conventionally the draw bar or shank of the coupler as being of the type described and claimed in my Patent No. 1,431,717, dated October 10, 1922, it will be understood that I do not wish to be limited to the use of my gear with such a type of coupler which provides for swiveling or horizontal angling of the head, as my gear is adapted for use with couplers of any desired character.

Disposed between the butt 26 of the coupler 2i and the front friction elements I8 is the front follower 24 designed to transmit. buffing forces from the coupler to said friction elements to effect compression of the gear 8. In order to provide for the unusual amount of rearward movement of the coupler for the transmission of buffing forces while still maintaining a normal shank construction, the follower Z4 is desirably notched,

as indicated at 28, so that the forward face thereof extends beyond, or is normally disposed forward of the rear ends of the slots 4, whereby said slots 4 may be extended the ncessary distance while still providing for lug or shouldered portions for limiting forward movement of the front follower.

From the foregoing description, it will be seen that under the action of draft forces the housing In is held stationary by the intermediate draft lugs l2 and the coupler pulls the yoke 9 forward- 22, thereby actuating only the rear cushioning mechanism or-unit whereby the cushioning effect is only a portion, for example, one-half, of the total capacity of the double ended gear and the travel of the coupler on draft with respect to the sills is less, for example, one-halfthat of the total permissible or normal compression of the gear.

Underthe action of buffing forces, however, the butt 26 of the coupler engages the front follower 24, pushing the front friction elements l3 into the front opening of the housing if! and imultaneously moving said housing rearwardly overthe rear friction elements l8 so that a full compression of the gear on buff is permitted, thereby providing for not only an increased buffing capacity, but for a coupler travel equal to the sum of the travel permitted by the friction elements at each end of the gear. Although for convenience and economy in manufacture the gear is preferably made so that the travel and the housing capacity provided by each end is identical, yet this is not essential in accordance with the broad aspect of the invention, so that the capacities and travels of the two ends of the gear may be either equal or different, as desired.

Referring now to the embodiment of my invention illustrated in Figs. 3, 4 and 5, a construction is there disclosed which may be identical with that of the first embodiment except that the intermediate stop means takes the form of upper and lower members l2 rather than side draft lugs, as in the previous embodiment. The upper member l2 desirably has depending flanges 29 connected to the sills I in any desired manner, as by rivets 30, said member be ing slotted between the sills, as indicated at 3|, for receiving the upper end of a vertical key 32, which key provides abutment surfaces, corresponding with those designated IZ of the previous embodiment, and passes through a slotted portion 33 in the housing Ill ofthe friction draft gear 8*, thereby providing abutment surfaces corresponding with those designated II of the first embodiment. The lower member l2 may be provided with similar upstanding flanges connected to the sills in a similar manner.

The lower end of the key 32 is received in a slot 34 in the lower stopmember 12 said key being retained in place in any desired manner, as, for example, by means of a retaining plate 35 closing the slot 34 after application of the key 32 and connected to the lower member l2 in any desired manner, as by means of tap bolts 3%. The key 32 is shown as fitting snugly in the slotted portion 33 of the housing III! while the slots SI and 34 are elongated rearwardly to a sufficient extent to permit the necessary rearward movement of the housing for actuating the rear friction mechanism therein, said key normally abutting the front end of the slotted portions of the stop members 12 for retaining the housing 8 against forward movement from normal position in a manner similar to that which the lugs 12 of the previous embodiment prevent :0 from moving forwardly from normal position.

As in the previous embodiment, I show a hooded vertical yoke 9 the hooded portion of which receives the coupler shank or butt 26 and is connected thereto by a key l received in slots 4 in stop members 3 If only one key 32 is employed for preventing forward movement of the housing H3 from normal position, the arms of the yoke are slotted, as indicated at 31, to permit forward movement of the yoke with respect to the key in order to provide for actuating the friction cushioning mechanism in the rear end of the housing m the yoke being correspondingly widened at the slotted portion, as indicated at 38, to maintain uniform stress in the arms thereof. I may, if desired, provide more than one key, for example, two, one on either side of the yoke arms, thereby avoiding the necessity of slotting said arms.

As in the previous embodiment, a back stop 2 may be provided for engagement by the rear follower 25 and the front follower 2% may be notched, as indicated at 28*, for the reasons described in connection with the first embodiment. The friction elements or wedges I8 and the springs 22 may correspond generally with those of the previous embodiment, the slight alterations in size illustrated being made to avoid interference between the inner ends of the friction wedges l8 and the slotted portion 33 of the housing I0 The wedges, if desired, may have lead inserts 39 for improving the smoothness in operation, which inserts may, if desired, be provided on the friction surfaces of the housing instead of on the wedges, or at both locations, if desired, as well as in similar locations on the gear of the first embodiment. Except as specifically described in connection with the present embodiment, the same may correspond substantially with that of the first embodiment.

From the foregoing disclosure, it will be apparent that I have devised a novel form of draft rigging with which a double-ended draft gear or cushioning mechanism is associated in a manner to provide a greater capacity for absorbing buffing energy than is provided for the absorption of draft energy. Although preferred embodiments of my invention have been illustrated, it will be understood that I do not wish to be limited to the forms shown, as modifications may be made within the spirit and scope of the appended claims.

I claim:

1. In railway draft rigging, in combination with draft sills, a draw bar and vertical yokeacting means, a friction draft gear comprising a column member provided with a vertical longitudinally extending slot disposed adjacent the central portion thereof, a plurality of sets of friction elements cooperating with said column member at each end, a follower at each end of the gear engaging corresponding friction elements, stop means for preventing forward movement of the front follower and rearward movement of the rear follower from normal position, said yoke-actingmeans embracing said gear and follower for actuating the rear elements on draft, means bridging the sills and disposed above and below said gear, and a key passingthrough the slot in the column member and corresponding friction surfaces on the housing, said housing being provided with vertical slots through the upper and lower walls thereof for receiving a connecting draft key.

3. A vertical hooded yoke adapted for receiving a double-ended slotted draft gear, the hooded portion of said yoke being slotted for receiving a horizontal key for connection with an associated draw bar, and the arms of said yoke rearwardly of said hooded portion being slotted to permit the passage of a vertical key.

4. A yoke comprising vertically spaced arms connected at their forward ends by a hooded portion slotted for receiving a horizontal draft key, said arms rearwardly of said hooded portion being slotted for receiving a vertical key.

5. In railway draft rigging, in combination with draft sills, a drawbar and vertical yoke-acting means, cushioning mechanism disposed rearwardly of said drawbar and embraced by said yoke-acting means, said mechanism comprising a housing, movable with respect to said sills, open at'both ends, and provided with inwardly converging friction surfaces adjacent each end, a set of friction elements at each end of the housing leaving an intermediate portion normally empty of cushioning means, each set engaging the inclined friction surfaces on its end of the housing, resilient means disposed between the friction ele- -ments of each set at each end of the housing for urging them into engagement with the friction surfaces on the housing, said intermediate portion of the housing being provided with forwardly facing stop shoulders at the sides thereof, causing the housing to be narrower at intermediate portions forwardly of said shoulders than at its ends, and positioned between the sets of friction elements at the ends of the housing, said sills being provided with stop means normally engaging said shoulders for limiting forward movement of the housing while permitting rearward movement thereof, and rear stop means for limiting rearward movement of the rear friction elements, while permitting rearward movement of the yokeacting means, whereby only the rear set of friction elements is actuated on draft while all of the friction elements are actuated on buff.

6. A draft mechanism comprising center sills, front and rear draft lugs arranged between the sills, a one-piece vertical hooded yoke positioned between said sills and consisting of top and bottom straps, a front hood and a rear butt, said hood having horizontal key slots, a double-acting draft gear positioned within the yoke and provided with a vertical slot in its medial portion, said yoke straps also having vertical slots in their medial portions, a key extending through said vertical slots for connecting the yoke to the draft gear, said gear including front and rear followers normally engaging respectively with the front and rear draft lugs, said butt engaging the rear follower when the yoke moves forwardly ondraft, a coupler shank extending into the hood of the yoke and normally engaging the front follower for moving the latter independently of the yoke during buff, and a horizontal key of less width than the length of said horizontal slots extending through said shank and the horizontal slots for causing the yoke to move forwardly with said shank.

7. A draft mechanism comprising center sills, front and rear draft lugs arranged between said sills, a one-piece vertical hooded yoke positioned between said sills and comprising top and bottom straps, a front hood and a rear butt, said hood having normally horizontal key slots, a doubleacting draft gear positioned within the yoke, and formed with abutment surfaces on a medial portion of a longitudinally movable housing thereof, normally vertically disposed, means formed with abutment surfaces cooperating with the firstmentioned abutment surfaces for the transmission of draft-mechanism-affecting forces, said gear including front and rear followers separate from said yoke and normally engaging respectively with the front and rear draft lugs, said butt engaging the rear follower when the yoke moves forwardly on draft and preventing the rearward movement thereof when said follower is positioned forwardly of the rear draft lugs, so that it is maintained in vertical position, a coupler shank extending into the hood of the yoke and normally engaging the front follower for moving the latter independently of the yoke during buff, and a horizontal key of less width than the length of said horizontal slots extending through said shank and horizontal slots for causing the yoke to move forwardly with said shank.

8. A draft mechanism comprising center sills, front and rear stops arranged between said sills, a one-piece vertical yoke device positioned between said sills and consisting of upper and lower elements rigidly connected adjacent the forward portion thereof, a double acting draft gear positioned between said elements and provided with a normally vertical slot in its medial portion, said upper and lower elements having slots normally registering with the draft gear slot, a key extending through the slots in said yoke device elements and draft gear for connecting said members, said gear including front and rear followers normally engaging, respectively, with the front and rear stops, and a coupler shank pivotally connected to said forward portion of the yoke device for causing it to move forwardly with said shank under draft, rearward movement of said coupler shank causing a corresponding movement of said front follower under buff.

9. In railway draft rigging, in combination with draft sills, a coupler, a vertical yoke device, a friction draft gear comprising a housing and a set of friction elements received in each end thereof, a front follower engaging the friction elements at the front end of the housing, cheek plates connected to said sills on opposite-sides of the stem of said coupler, each cheek plate having a slot and a front stop portion, the rear end of said coupler in normal position lying forward of the stop face plane of said front stop portions, said front follower having shoulders disposed rearward of the follower front face, said front face being extended forward and normally engaged by the coupler, stop means holding the housing against forward movement while allowing rearward movement thereof, so that the coupler may be of normal construction and move rearwardly a double distance for actuating the friction elements at both ends of the housing, while only moving forwardly an amount suincient to actuate the friction elements at one end only, and a key with its ends received in said slots and connecting said coupler stem and yoke device, said slots being extended rearwardly beyond the normal position of the follower front face an amount sufiicient to allow for the rearward movement of the coupler for full compression of the draft gear.

10. In railway draft rigging, in combination with draft sills, a drawbar and vertical yoke-acting means, a friction draft gear comprising a unitary hollow open-ended housing, longitudinally movable with respect to said sills, formed with side walls normally disposed close to the inner faces of said sills at the ends thereof, a cushioning unit received in each end of said housing and normally spaced from that at the other end leaving an intermediate portion free of mechanism, front and rear followers engaging and said yoke-acting means embracing said gear and associated followers for actuating only the rear cushioning unit on draft, while the housing is prevented from forward movement bythe intermediate stop means.

11. In railway draft rigging, in combination with draft sills, a drawbar and vertical yokeacting means, a friction draft gear comprising a movable column member formed with side 'walls normally disposed close to the inner faces of said sills at the ends thereof, a plurality of sets of friction elements cooperating with end portions of said column member, a follower at each end of the gear engaging corresponding friction elements, front stop means normally engaged by the front follower for preventing forward movement thereof, rear stop means normally engaged by the rear follower for preventing rearward movement thereof, the intermediate portion of said column member having its side walls inset away from the inner faces of said sills to provide a portion narrower than the end portions and formed with shoulders at the front ends of the rear end portion, and intermediate stop means connected to the sills and normally engaging the shoulders on the column member and preventing forward movement, clearance permitting rearward movement of said column member, from normal position, and said yoke-acting means embracing said gear and associated followers for unitary hollow open-ended housing, longitudinally movable with respect to said sills, formed with side walls normally disposed close to the inner faces of said sills at the ends thereof, a cushioning unit received in each end of said housing and normally spaced from that at the other end leaving an intermediate portion free of mechanism, front and rear followers engaging corresponding cushioning units, front stop means normally engaged by the front follower, rear stop means normally engaged by the rear follower, said intermediate portion having the side walls set closer together than at the ends, providing shoulders encroaching on the width of the housing, as permitted by the freedom from mechanism, and disposed between said cushioning units, and intermediate stop means, connected to the sills, received in the pockets formed by the closer positioning of the intermediate portion side walls, and normally engaged by said shoulders for preventing forward movement only of said housing, and said yoke-acting means embracing said gear and associated followers for actuating only the rear cushioning unit on draft, while the housing is prevented from forward movement by the intermediate stop means.

13. In railway draft rigging, in combination with draft sills, a drawbar and vertical yokeacting means, a friction draft gear comprising a unitary hollow open-ended housing formed with side walls normally disposed close to the inner faces of said sills at the ends thereof, a cushioning unit received in each end of said housing and spaced from that at the other end leaving an intermediate portion free of mechanism, front and rear followers engaging corresponding cushioning units, front stop means normally engaged by the front follower, rear stop means normally engaged by the rear follower, said intermediate portion having shoulders encroaching on the width of the housing, as permitted by the freedom from mechanism, and disposed between said. cushioning units, and an upright key, connected to the sills, passing through said housing between said cushioning units, and normally engaged by ing means, a friction draft gear comprising a movable column member, a plurality of sets of friction elements cooperating with said column member at each end, a follower at each end of the gear engaging corresponding friction elements, front stop-means for preventing forward movement of the front follower, said stop means having slots therein, stop means intermediate the ends of said column member for holding the latter against forward movement, while allowing rearward movement thereof so thatthe drawbar has arelatively-long movement on buff for actu= ating the friction elements at both ends and ai relatively short movement on' draft for actuating the friction elements at one end only, a key connecting said drawbar and vertical yoke-acting means and received in said slots, said slots extending rearwardly beyond the normal position of the rear edge of the key a sufficient distance to permit said relatively long movement for full compression of the draft gear, the rearend of said drawbar'in normal position lying forward of the stop face plane of said front stop means and' the rear ends of the slots in'said front stop means, said front follower being notched where it engages the front stop means to permit the front face thereof tonormally extend forwardly of said stop' means, and rear ends of the slots therein, into engagement with the drawbar, back stop means for preventing rearward movement of the rear follower, and said yoke-acting means embracing said gear for actuating the rear elements on draft.

15. In railway draft rigging, in combination with draft sills, a drawbar and vertical yoke-acting means, front and rear cushioning units, a follower at the front end of the front unit, and one at the rear end of the rear unit, front stop means for preventing forward movement of the front follower, said stop means having slots therein,

means intermediate the units to form front stop means for the rear cushioning unit, while allowing rearward movement of both units, so that the drawbar has a relatively long movement on buff for actuating both units and a relatively short movement on draft for actuating only one unit, a key connecting said drawbar and yoke-acting means and received in said slots, said slots extending rearwardly beyond the normal position of the rear edge of said key a distance sufficient to permit said relatively long movement for full compressionv of both units, the rear end of said drawbar in normal position lying forward of the.

embracing both cushioning units for actuating the rear unit on draft.

16. In railway draft rigging, in combination with draft sills, a drawbar and vertical yoke-act ing means, a friction draft gear comprising a movable column member formed with side walls normally disposed close to the inner faces of said sills at the ends thereof, a plurality of sets of friction elements cooperating with the end por- 'tions of said column member forming front and rear cushioning units, a follower at each end of the gear, front stop means normally engaged by v the front follower for preventing forward movement thereof, said stop means having slots therein, the intermediate portion of said column memher having its side walls set closer together than at the ends, providing shoulders disposed between said cushioning units, intermediate stop means connected to the sills and normally engaged by said shoulders, for preventing forward movement only of said housing, so that the drawbar has a relatively long movement on bufi for actuating both cushioning units and a relatively short movement on draft for actuating only one 2;; cushioning unit, a key connecting said drawbar and yoke-acting means and received in said slots, said slots extending rearwardly of the normal position of the rear edge of said key. a distance sufficient to permit said relatively long movement for full compression of the gear, the rear end of said drawbar in normal position lying forward of the stop face plane of saidfront stop means and the rear ends of therslots in said means, said front follower being notched where it engages said stop means to permit the front face thereof to normally extend forward of said stop face plane and the rear ends of the slots in said stop means, into engagement with the drawbar, backstop means for preventing rearward movement of 40 the rear follower, and said yoke-acting means embracing said gear for actuating the rear cushioning unit on draft.

17. In railway draft rigging, in combination with draft sills, a vertical yoke device positioned between said sills and consisting of upper and 5 lower elements rigidly connected adjacent the forward portion thereof, a double-acting draft gear positioned between said elements, provided with a housing having a normally vertical slot in its medial portion, and comprising a cushioning 10 unit at each end, said upper and lower elements having slots normally registering with the housing slot, a connecting draft key extending through the slots in said yoke device elements and housing, front and rear stop means, said 15 front stop means having slots therein, front and rear follower means normally respectively engaging the front and rear stop means, a coupler with a shank 'pivotally connected to the forward portion of the yoke device, the connecting means 20 for said coupler shank including a key received in the front stop means slots, said slots extending rearwardly beyond the normal position of the rear edge of said key a suflicient distance to permit relatively long movement of the coupler for 25 full compression of the gear, the rear end of said coupler shank in normal position lying forward of the stop face plane of said front stop means and the rear ends of the front stop slots, said front follower means being notched where it engages the front stop means to permit the front face thereof to normally extend forward of said stop face plane, and the rear ends of the slots in said stops,into engagement with said coupler shank, said rear stop means preventing rearward movement of the rear follower, and said yoke device actuating only one of said cushioning units on draft.

DONALD s. BARRoWs.

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