US2897980A - Draft mechanism - Google Patents

Description

Inventor; Emil H. Blattner his Attorney E. H. BLATTNER DRAFT MECHANISM Filed Dec Aug. 4, 1959 ,United States Patent gGiiice 2,897,980 Patented Aug. 4, 1959 DRAFI MECHANISM Emil H. Blattner, Williamsville, N.Y., assignbr to Symington Wayne Corporation, a corporation of Maryland Application December 14, 1953, Serial No. 397,832

9 Claims. (Cl. 213--32) This invention relates to draft mechanism for railway cars and is an improvement on the cushioning mechanism of my Patent No. 2,540,041, dated January 30, 1951.

In the cushioning mechanism of the foregoing patent.

a plunger is built into the draft gear and serves as the medium by which buiiing and draft forces are transmitted to the associated friction devices. Since built in, the plunger must in some manner be held in assembled rela- -tion with the draft gear, and in my patent Vthis is accomplished by the provision of an interlock between the plunger and the housing of the draft gear. Although effective in maintaining the assembly, such an interlock requires considerable lateral play between the plunger and the housing to accommodate the relative angling or canting of the plunger necessary for assembly.

An object of the present invention is to provide in draft mechanism an improved interlock between a built-in plunger and the associated structure of va draft gear, whereby lthe plunger is enabled to be assembled and locked in assembled relation with the other structure without relative angling of the plunger.

Another object of the invention is to provide draft gear, having a built-in plunger wherein the plunger is held in assembled relation by an interlock with the friction devices, enabling lateral clearance between plunger and housing to be held at a minimum so that the confronting surfaces of the housing may serve to guide and center the plunger in its movements relative to the housing.

An additional object of the invention is to provide draft mechanism wherein a rubber cushion is interposed between a separate follower block and a plunger built into a draft gear for permitting the follower block to angle under lateral forces from the `associated coupler without transmitting the angling movement to the plunger, thus enabling the plunger to be restrained against angling by the housing without adverse eiect upon thev action of the draft mechanism.

A further object of the invention is to provide draft mechanism wherein a rubber cushion is interposed between a plunger built into the draft gear and a separate front follower block, the rubber cushion serving notonly to absorb any angling of the follower block. underforce from the associated coupler, but to insulate. the vassociated draft sills from direct metal-to-metal blowsy under impacts that would otherwise force the vdraft gear solid.

Other objects and advantages of the invention will appear hereinafter in the detailed description, be'particularly pointed out in the appended claims, and be illustrated in the accompanying drawings, in which:

Figure l is a plan view, partly inl longitudinal section, of a preferred embodiment of the draft mechanism of the present invention, with other por-tions broken away and shown in section fto more clearly illustrate certain of the details of construction. p f

Figure 2 is a fragmentary side'elevational view, partly in vertical section, of the draft mechanism of Figure l.

Figure 3 is a verticalsectional view takenA along the linesS--S of Figure'l; and

Figure 4 is a fragmentary side elevational view with the housing in section, illustrating the preferred mode of assembly of the plunger.

Referring now in detail tothe drawings, in which like reference characters designate like parts, the improved draft mechanism of the present invention is comprised of a draft gear 1 having a built-in plunger 2, the

draft gear generally resembling the draft gear of my Patent No. 2,540,041. As in the case of the draft gear of the patent, that here disclosed has a friction housing, barrel or casing 3 open at one end and having vits hollow interior 4 closed longitudinally by top and bottom walls 5 and connecting side walls 6, and at'one end by an end or rear wall 7 integral with and connecting the several longitudinal Walls.

ln the rear portion of the hollow interior 4 is a rear pocket or cavity 8 in which are contained and seated suitable release spring or resilient means 9, here illustrated as formed of three nested coil springs. The springs 9 bear at their rear ends against the rear or end wall 7 and at their front or forward ends against a floating follower 10, the forward or front face 11 of which abuts and preferably is rubbed against or frictionally engaged by the rear ends 12 of friction elements 13, the latter preferably taking the form of a pair of counterpart friction wedges or shoes whose rear ends 12 are transversely or laterally directed and substantially planar.

As its name implies, the friction housing 3 is designed to be frictionally engaged by the wedges 13. To this end, its side walls 6 toward the open end 14 of the housing, have, as their inner faces, preferably planar friction or wedging surfaces 15. Here, two pairs of such surfaces are provided, one pair 16 positioned inwardly of the other pair 17, longitudinally of the housing, and the surfaces of each pair being oppositely inclined or sloping and aring or diverging forwardly toward the open end of the housing. It will be observed that the two friction surfaces on each side wall are substantially parallel and in stepped arrangement and that they are connected by integral instanding or inwardly directed shoulders or abutments 18, later to `be described.

To utilize the two pairs of friction surfaces on the housing, each of the wedges 13 has on its outer face a like pair of relatively stepped friction or wedging faces 19, each confronting and adapted to frictionally engage one of the friction surfaces of the adjacent of the top and bottom walls 5. For maintaining the frictional engagement between the several friction surfaces 15 and faces 19, the wedges 13 are normally urged apart or outwardly, laterally or transversely of the housing, by laterally or transversely acting spring means suitable for this purpose, such as the illustrated opposed packs or sets of semi-elliptic leaf springs 20. Stepped in the same manner as the friction surfaces 15, the friction faces 19 of each Wedge are connected by outstanding or outwardly directed shoulders or abutmcnts 21 which are adapted to overlap and interlock with the shoulders 18 on the housing and limit the forward longitudinal movement of the wedges 13 relative to the housing, the wedges being of such length as to be contained or enclosed within the housing in the interlocked position of the shoulders.

Like the plunger of my patented cushioning mechanism, the built-fin plunger or follower 2 of the draft mechanism of the present invention is Iapplied to the open end 14 o f the'housing and is adapted to seat or t in the mouthl 22 of the latter.- It, also, is designed to limit or determine the permissible compressive movement of the draft gear 1, having rfor this purpose an outer peripheral lip or flange 23 overlapping the open end of and of substantially the same overall transverse dimensions as the housing 3.v Normally spaced forwardly of the open end 14, the lip 23 is adapted to abut with that end on full closure,

3 the initial spacing `of the lip thus determining the extent of movement of the draft gear between initial position and full closure.

Inwardly or rearwardly of its lip 23, towards the housing 3, the plunger has a restricted throat or intermediate portion 24- which may have rearwardly converging top and bottom walls 25 and parallel-sided side walls 26, the outer portion of the mouth 22 of the housing being of corresponding configuration so as to contain these walls within thehousing on full closure. The intermediate portion 24 of the plunger terminates inwardly or rearwardly in a transversely directed, substantially flat inner face 27 which, initially or normally, is in substantially the plane of the open yend 14 `of the housing `and is rubbed against and rfrictionally engaged by the forward transversely directed ends v28 of the wedges 13.

In my patented cushioning mechanism the plunger in` terlocks with and is held in assembled position by lugs fixed to and instanding from the housing, and the fixed position of the lugs relative to each other requires the plunger to be angled or canted relative to the housing to enable it to be assembled. The plunger 2 of the draft mechanism of the present invention is designed, instead, to interlock with the wedges 13 and use is made of the decrease in the lateral spacing between the wedges as Athey contract to free or clear the plunger from the interlock so that it can be slid straight into the mouth 22 of .the housing. This, in turn, permits the lateral clearances between the plunger and housing to be reduced so that e the housing can be made to guide and center the plunger in its relative longitudinal movement.

Since the plunger 2 will be forced into and thus held vto the housing by any compressive forces applied to the .the latter. At the same time, provision is made on the housing for guiding the guide members and thus the plunger, once the guide members are inserted.

kIn the disclosed embodiment four such guide members 29 are provided in the form of posts, projections or legs, integral with theplunger, one positioned at each of the corners of and projecting or extending rearwardly of the rear face 27 of the plunger. Each of these posts is adapted, in turn, to seat in normal position in a slot or groove 30 in one of the wedges 13, the slots opening forwardly to receive the posts and outwardly in the direction ofexpansion of the wedges to accommodate the relative lateral movement therebetween. Arranged in correspondence with the arrangement of the posts, each of the `slots 30 is insetinto and interrupts the outer pair 17 of the friction surfaces on the wedges at one of the outer corners of the latter. Opening laterally onto each of the `slots 30 and extending longitudinally of the housing a distance sulcient to accommodate longitudinal movement of the posts 29 isa guideway, slideway or guide channel 31 yfor slidably receiving the associated of the posts.

Positioned in the disclosed embodiment at the four corners of the housing and inset in and interrupting 'the friction surfaces :15, the several guideways 31, as wellas the guide vposts 29, have their bearing or engaging surfaces extending or disposed parallel to the longitudinal axis of the housing so that the plunger 2 will move along and be centered relative to that axis in itslongitudinal movement .with respect to the housing. In `the form shown, each of the guide posts hasas its bearingsurface Va pair of flat angularly related longitudinal bearing faces `32, each confrontingand adapted to bear against and 4 slidably engage one of the pair of correspondingly related guide surfaces 33 of each of the guideways.

For releasably interlocking the posts with the wedges 13 in the normal position or expanded condition of the draft gear, it suffices that outwardly facing portions on the wedges intercouple or mate with confronting inwardly facing portions on the posts. Such intercoupling or interlocking here is accomplished by a dovetail interlock, obtained by so inclining or sloping the outwardly facing side walls 34 of the several slots 30, which confront the friction surface-carrying longitudinal walls 5 of the housing, that these side walls on each wedge fiare or diverge forwardly relative to the companion or opposite side walls on the other wedge. To complete the interlock, the inwardly facing longitudinal surfaces 35 on the posts confronting the flaring side walls 34 `of the slots are also inclined or diagonally directed and those on each wedge converge rearwardly relative to the corresponding surfaces on the other wedge. Forming in the posts, forwardly of their rear extremities, inwardly opening or facing sockets 36sand on `the wedges outstanding or outwardly facing mating lugs 37, the several side walls 34 and surfaces 35 provide a lateral overlap between the posts and wedges which interlocks them in the normal position of the latter and effectively limits outward movement of the plunger 2 relative to the housing. To minimize weakening of the posts by their undercutting inner surfaces 35 both these surfaces and the flaring side walls 34 on the wedges may be ,conically surfaced, the former concave and the latter convex.

While considerable clearance is shown between the bearing faces 32 on the posts 29 and their guide surfaces 33 on the housing, such clearance is not necessary, since yangling of the plunger 2 relative to the housing is not contemplated and, if the parts are machined and not left as rough castings, may be reduced to the point where the posts have a sliding fit with their guideways 31. But whether or not machined, the sliding engageability of these faces restrains angling and serves to center and guide the plunger in 'its longitudinal movement relative to the housing.

With relative angling between housing and plunger eliminated andthe associated coupler (not shown), on angling, normally transmitting lateral forces to the draft mechanism, cushioning of such forces is needed to prevent interference with the intended longitudinal guiding of the plunger. Such cushioning is here obtained by the interposition between the front face 38 of the plunger and a front follower block 39, of form suitable for the type of the associated coupler, of a rubber cushioning unit 40. This unit serves not only to absorb and thus effectively free the plunger of lateral forces, but also acts in tandem with the draft gear 1 as an additional cushioning element to both increase the overall capacity of the draft mechanism and eliminate the transmission of over-solid blows to the associated draft sills (notshown). A rubber cushioning unit especially suited for both purposes is a rubber spring element of a rubber cushioning mechanism such as shown in my copending application, S.N. 380,545, filed September 16, 1953. The illustrated rubber spring element is formed of a plurality of rub- Ybei' mats 41 spaced by and bonded through a center plate 42. Arranged in tandem with the draft gear, the rubber cushion or cushioning unit 40 affords to the draft mechanism the characteristic no-solid point of rubber cushion draft gears and the draft gear 1, in turn, promaar sorbs lateral forces from the associated coupler and thus prevents interference with guiding of the plunger. It should be understood that the disclosed and described embodiment is merely exemplary of the invention and that all modifications are intended to be included which do not depart either from the spirit of the invention or the scope of the appended claims.

Having described my invention, I claim:

1. Draft mechanism comprising a housing, friction means in and frictionally engaging said housing, spring means normally urging said friction means forwardly of said housing, a plunger projecting forwardly of and extending into said housing and having portions straddling and interlockable with portions of said friction means, guide means in said housing and engageable with said plunger for guiding said plunger during longitudinal movement thereof, and rubber cushioning means disposed forwardly of said plunger and interposed between said plunger and a front follower block.

2. Draft mechanism comprising a housing, friction elements within and frictionally engaging said housing, spring means normally urging said friction elements forwardly of said housing, a plunger projecting forwardly of and extending into said housing and having portions straddling and interlockable with portions of said friction elements, guide means in said housing for guiding and centering said plunger during relative longitudinal movement thereof, and rubber cushioning means disposed forwardly of said plunger and interposed between said plunger and a front follower block Ifor both insulating said plunger from lateral forces and associated draft sills from metal-to-metal impacts and increasing the ultimate capacity of said draft mechanism.

3. Draft mechanism comprising a friction housing, counterpart friction shoes within said housing, spring means within said housing and normally urging said shoes forwardly thereof, a plunger for limiting the compression of said shoes and spring means, portions on said plunger projecting into said housing and interlockable with said friction shoes, guideways in said housing for receiving and guiding said projecting portions and therethrough said plunger during longitudinal movement thereof relative to said housing, and rubber cushioning means arranged in tandem with said friction shoes and spring means and interposed between said plunger and a front follower block for relieving said plunger of lateral forces from an associated coupler.

4. A draft gear comprising a friction housing open at one end, friction shoes in and frictionally engaging said housing, spring means in said housing and normally urging said shoes outwardly thereof, a plunger projecting forwardly of and frictionally engaging said friction shoes and having guide portions instanding into the open end of said housing, matable means on said guide portions and friction shoes and matable in an expanded condition of said gear for locking said plunger to said shoes, and guideways in said housing and each slidably receiving one of said guide portions for guiding said plunger in longitudinal movement thereof relative to said housing.

5. A draft gear comprising a friction housing open at one end, friction shoes in and frictionally engaging said housing, spring means normally urging said shoes forwardly of said housing a plunger projecting forwardly'of and engaging outer ends of said shoes, spaced .guide posts integral with said plunger and projecting 1nto the open end of said housing, laterally overlapping means on said guide posts and shoes for limiting outward movement of said plunger relative to said shoes, and guideways in said housing and slidably engaging said guide posts for guiding and centering said plunger on longitudinal movement thereof relative to said housing.

6. A draft gear comprising a friction.v housing a Pair of counterpart wedge members Within said housing, wedging faces on said wedge members and frictionally engaging wedging surfaces on said housing, spring means between and acting outwardly on said wedge members for frictional engagement thereof with said housing, a plunger engaging said wedge members and having spaced guide post members extending into the open end of said housing, laterally extending lug means on one of said wedge and guide post members and seatable in socket means in the other of said wedge and guide post members for limiting outward movement of said plunger relative to said housing, and guideways in said housing and each slidably receiving one of said guide post members for guiding said plunger on longitudinal movement thereof relative to said housing.

7. A draft gear comprising a friction housing open at one end, counterpart wedges in and lockable to said housing and frictionally engaging opposite longitudinal sides thereof, spring means in said housing for urging said Wedges laterally and longitudinally thereof, a plunger, and portions on said plunger projecting into said open end of said housing and straddling said wedges, said wedges dovetailing with said portions in an expanded condition of said draft gear for interlocking said plunger with said housing.

8. A draft gear comprising a friction housing open at one end, a pair of counterpart wedges in and lockable to said housing and frictionally engaging opposite longitudinal sides thereof, spring means in said housing for urging said wedges laterally and longitudinally thereof, a plunger, laterally spaced portions on said plunger, said portions projecting rearwardly of said plunger into said housing and in an expanded condition of said gear seating in outwardly facing slots in and embracing said wedges, and a sloping surface on said wedges defining outwardly facing walls of said slots and each diverging forwardly relative to said surface on said other wedge, said surfaces dovetailing with correspondingly sloping surfaces on said plunger portions for interlocking said plunger and wedges in normal position.

9. A draft gear comprising a friction housing open at one end, counterpart wedges in and frictionally engaging opposite longitudinal sides of said housing, spring means in said housing for urging said wedges laterally and forwardly thereof, a plunger, laterally spaced portions on said plunger, said portions projecting rearwardly of said plunger into said housing and in an expanded condition of said gear seating in slots in and embracing said wedges, sloping surfaces on said wedges defining outwardly facing walls of said slots and dovetailing with correspondingly sloping surfaces on said plunger portions for interlocking said plunger and wedges in normal position, and guideways extending longtudinally of said housing and each opening into one of said slots for slidably receiving and guiding said portions and therethrough said plunger during longitudinal movement thereof relative to said housing.

References Cited in the le of this patent UNITED STATES PATENTS 1,303,380 OConnor May 13, 1919 1,862,764 OConnor June 14, 1932 1,884,516 Barrows (Jet. 25, 1932 1,951,086 Davis Mar. 13, 1934 2,141,680 Barrows Dec. 27, 1938 2,225,418 Larsson Dec. 17, 1940 2,331,458 Dath Oct. 12, 1943 2,515,188 Brennan July 18, 1950 2,527,589 Spence et al. Oct. 31, 1950 2,540,041 Blattner Jan. 30, 1951 2,552,668 Dath May 15, 1951 2,554,606 Withall May 29, 1951

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