US2811264A

US2811264A - Friction draft gear

Info

Publication number: US2811264A
Application number: US404989A
Authority: US
Inventors: William E Gray
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-01-19
Filing date: 1954-01-19
Publication date: 1957-10-29
Anticipated expiration: 1974-10-29

Description

Oct. 29, 1957 Filed Jan. 19, 1954 W. E. GRAY FRICTION DRAFT GEAR 2 Sheets-Sheet 1 /7 ODA/E YS.

Oct. 29, 1957 w. E. GRAY 2,811,264

FRICTION DRAFT GEAR Filed Jan. 19. 1954 2 Sheets-Sheet 2 if P/VEYS.

nite States FRICTION DRAFT GEAR William E. Gray, West Lafayette, Ind.

Application January 19, 1954, Serial No. 404,989

8 Claims. (Cl. 213-45) This invention relates to draft gears, and more particularly to draft gears in which the cushioning element is a block or a series of blocks of rubber or similar compressible material.

Among the objects of the invention are to produce an improved draft gear which can be sirnply and economically manufactured and which, in service, will prove durable and effective to accomplish its intended purpose; to prevent damage to the rubber cushioning material or interference by that material in the proper functioning of the gear; and to improve the releasing operation of the gear.

In carrying out the invention in its preferred form, I provide an elongated, cylindrical hollow sleeve or housing, preferably of oval cross section; and within such housing, at each end thereof, I provide a pair of laterally separable shoes adapted to bear frictionally against the inner surface of the housing when the gear is collapsed under draft or bufng loads to move the shoes longitudinally of the housing. The opposed faces of the shoes of each pair are recessed to provide for the reception of blocks of rubber or similar elastically compressible material which oppose movement of either pair of shoes toward the other and which, when compressed longitudinally as the result of draft or bufling loads, expand transversely to force the shoes outwardly against the housing. To prevent the rubber blocks from becoming pinched between the shoes, they are surrounded by sheet-metal liners bridging the gap between the shoes. Desirably, the housing-engaging surfaces of the shoes are not complementary to the inner surface of the housing but instead are so shaped as to engage the housing only at and near their midpoints; and the housing is elastically distortable so that when the shoes are forced apart as a result of draft or bufng loads, the housing will be distorted to increase the area of contact between its inner surface and the shoes. This feature facilitates release of the gear and tends to prevent it from becoming locked in closed condition. The accompanying drawings illustrate the invention:

Fig. l is a longitudinal, horizontal section through a draft gear in open condition;

Fig. 2 is a transverse vertical section on the line 2 2 of Fig. l;

Fig. 3 is a view similar to Fig. l, but illustrating the gear in closed condition; and

Fig. 4 is a View similar to Fig. 2 but showing the condition existing when the gear is closed.

The draft gear is shown inthe drawings as carried from draft or center-sills of a car frame and between front and

rear stop lugs

11 and 12. In a manner yet to be described, the gear is adapted to cushion both car-pushing and car-pulling shocks transmitted by the car-pushing draw-bar 13, or by the car-pulling yoke 14, through the draft gear to the car frame. A front follower block 16 located in rear of the lugs 11 engages the adjacent ends of a front pair of friction shoes 17; while a rear follower block 18 lying in front of the rear stop lugs 12 engages the rear ends of a pair of rear shoes 19. The shoes 17 and i9 are located within a housing 21 against the inner 2,811,264 Patented Oct. 29, 1957 ice surface of which the shoes of each pair are forced upon closing of the gear.

The two shoes of each pair are provided in their opposed faces with recesses cooperating to provide a generally cylindrical cavity within which are located blocks 23 of rubber or similar elasticaily compressible material. As shown, there are an inner and an outer compressible block Z3 located within the cavity defined by each pair of shoes, such two blocks being separated by a rigid inter mediate spacer 28. The shoes are provided at their outer ends with flanges 25 which extend toward each other across the end of the block-receiving cavity; and between each pair of such flanges and the adjacent outer block 23 there is interposed an end spacer 26.

In the open position of the gear, rshown in Fig. l, the two pairs of shoes project outwardly beyond the ends of the housing 21 into engagement with the

follower blocks

16 and 18; and at their inner ends the two pairs of shoes are spaced apart to permit them to move toward each other as an incident to closing of the gear. A rigid filler block 24, dimensioned to enter the cavities containing the blocks 23, is interposed between the inner ones of such blocks. The extent of the block 24 longitudinally of the gear is such that with the gear fully open the block 24 projects into each cavity for a short distance.

When the gear is called upon to cushion a butiing jolt transmitted through it from the draw bar 13 to the rear stop lugs 12, the rearward movement of the draw bar 13 forces the front follower block rearwardly. Since rearward movement of the rear follower block is prevented by its engagement with stop lugs 12, the two pairs of

shoes

17 and 19 will be forced toward each other and the rubber blocks 23 will be compressedlongitudinally and expanded laterally, the latter action forcing the two shoes of each pair outwardly away from each other and into hrm frictional engagement with the inner surface of the housing 21. Collapse or closing of the gear will thus be opposed both by the resilient resistance of the rubber blocks and by friction between the shoes and the housing; and both those components will increase as closing proceeds toward its limit. Under a draft or pulling shock, the action is essentially the same, the only difference being that the rear follower block 18 moves forwardly While the front follower block is held against forward movement by the front stop lugs 11.

When closing of the gear has been completed, its subsequent opening or extension is effected as a result of longitudinal forces exerted by the compressed blocks 23 upon the shoe-anges 25; and as the compressed blocks are forcing the shoes outwardly against the housing, friction between the housing and the shoes will oppose opening of the gear. lock in closed condition as arresult of such friction I prefer to shape the housing 21 and the shoes in such a manner that their interengaging faces are not exactly complementary with each other. As indicated in Fig. 2, the housing is preferably generally oval in cross-section, and the shoes of each pair are arranged to move toward and away from each other along the major axis of the oval. The shoes are so shaped that when the gear is open they engage the `housing only 'at 'points near their center, or adjacent the ends of the major housing-axis. In other words, the side surfaces of the shoes are relieved t0 provide clearance such as is indicated atv 32 in Fig. 2.

The housing possesses sufficient elastic distortability to permit it to collapse vertically, or in the direction of its minor axis, when the shoes are forced apart toexpand the housing horizontally or along its major axis. Such reduction in the minor axis of the housing increases the area of contact between it and the shoes, bytaking up the clearance 32. As a result of the arrangement just described, the tendency of the gear to lock closed To reduce the tendency of the gear toV position is materially reduced, as more fully set forth and described in my co-pendingV application Serial No. 295,718', led June 26, 1952.

To eliminate the possibility that any portion of the rubber blocks will be pinched between the shoes upon closing of the gear, the blocks are desirably surrounded with sheet-metal liners bridging the gaps at which any suchl pinching might occur. As shown,l one such liner is associated with each pair of shoes, the liner comprising two pieces of sheet-metal each bent into an arcuate crosssection of somewhat more than 180 extent so that when inplace their edge portions will overlap, as indicated at 33- in Fig. 2. Adjacent the end spacer 26, portions of each liner are bent inwardly to provide tlanges or tongues 35 overlying the outer end of the adjacent block 21% to locateI the linerY axially of the associated. shoes and to prevent entry of the compressible material into the spaces between the shoes and the spacer 26 when the gear is closed. At its opposite end, each liner laps the ller 24, but does not extend thereover far enough to engageV the adjacent end of the opposite` linerv upon closing of the gear.

The housing 21 is not anchored to` the sills 10, but is free to float longitudinally as limitedy by its possibilities of engagement with the follower blocks 16v and 18. To insure that the housing is centered longitudinally with respect to the shoes when the gear isV open, at least one of the shoes 17 and one of the shoes 19 is provided in its outer surface with a groove 37' which extends inwardly of theV shoe to a point within the housing 21, and the housing 21 is provided with pins 38 received in such grooves. The arrangement is such that when the gear is open the pins-38 lie at the inner ends of the grooves 37, thus locating the housing in denite, centered position, with respect to the shoes and preventing one pair of' shoes from projecting outwardly beyond the housing when the gear is in the open (Fig. l) condition, the.

grooves 37 and pins 38 perform the additionalfunction of holding the overall length ofthe shoes-and-housing assembl-yto a predeterminedn maximum suchas to facilitate its positioning between the

follower blocks

16 and 18.

As indicated, the rubber blocksV 23 are provided with holes 40 extending through them longitudinally of the gear.- Aswill be obvious, the number and cross-sectional area of such holes will determine' thel lateral pressure exerted by each block when compressed longitudinally to any given extent. Holes 40, which taper toward their longitudinal centers, as shown in- Fig. 1, are preferred, as such holes tend to assume a cylindrical form (Fig. 2) when the blocks 23' are-compressed' upon. closing of the gear.

I claim as rnyinvention:A Y

1. Ina draft gear having a longitudinally extended housing and a pair of opposed" shoes longitudinally movable in said housing, means operable in response to draft or buing forces formoving said shoes longitudinally in-said housing, and a massY of compressible, resilient material for opposing such longitudinall movement of said shoes, said mass beingv confined between. said shoes whereby when compressed longitudinally itv will expand laterallyto urge said shoes apart and: into rm frictional'- contact wit-h the innerA surfaceY of' the housing, said housing being circumferentially continuous and' elastically distortable, said shoes respectivelyhavingcentralportions engaging said housing at adjacent opposite ends; of a diameter thereof, whereby outwardLv pressure. exerted on the-` housing by the central portions of the shoes will. enlargei the housinginthe'` direction of suchdiameter and: contractI it the-perpendicu1ar direction,

. 4 said shoes having side portions spaced from the housing when the latter is undistorted but engageable by the housing when it contracts in such perpendicular direction.

2. A draft gear as set forth in claim 1 in which the housing is of generally oval cross-section, the shoes being disposed within the housing in such positions that their respective center portions engage the housing at and adjacent the ends of its major diameter.

3. The invention of claim 1 with.' the addition that there are two pairs of said shoes locatedl respectively at opposite ends of the housing and movable toward each other under draft or buthng forces, the two shoes of each pair being provided with opposed recesses defining a cavity, said mass of compressible material including two blocks located respectively in said cavities, and a rigid filler block disposed between the blocks of compressible material and extending into both said cavities.

4. The invention of claim 1 with the addition that the opposed faces of` said shoes are recessed to provide a cavity for the reception of said mass of compressible material, and a sheet-metal liner disposed between said mass and said shoes, said liner overlapping both said shoes peripherally of said mass of compressible material and extending longitudinally of the shoes for the length thereof.

5. The invention of claim 1 with the addition that the opposed faces of said shoes are recessed to provide a cavity for the reception of. said mass of compressible material', and a sheet-metal liner surrounding said mass andv extending longitudinally of the draft gear for the length of said mass.

6. In a draft gear havinga longitudinally extended housing and a pair of opposed. shoes longitudinally movable in said4 housing, means operable in response to draft or buing forces for moving said shoes rearwardly in said housing, the opposed. faces of said shoes being recessed to provide a cavity, ablock of resilient compressible material located in and confined by said cavity for opposing rearward movement of the shoes inthe housing whereby said block, when compressed longitudinally, will expand laterally to urge the shoes apart into hrm frictional engagementwith the housing, and a sheet-metal liner disposed between said block and shoes.

7l In aY draft gear having a longitudinally extended housingI and a pair of opposed shoes longitudinallyv movable in said housing, means operable in response to draft or huling forces for moving said shoes rearwardly in said housing; ther opposed faces of said shoes being recessed. to providev a cavity, a block of4 resilient com-A pressibleY material located in and confined by said cavity for opposing rearward. movement of the shoes. in the housing whereby said block, when compressed longitudihally,. will. expand laterally to' urge the shoes apart. into firm frictional engagement with thehousing, and a sheetmetal liner surroundingl saidv mass.

8. The invention of claim 6'with the addition that said shoes are provided at their outer ends with flanges dening a bottom for said cavity, said liner having an inbent tlange conned between said block and at least one of saidshoe-anges.

References` Cited in the le` of this patent- UNTTEDv STATES PATENTS- 1,200,642 OConnor Oct. 10, 1916 1,512,926 Haseltine Oct. 28, 1924 2,222,479 Cottrell Nov. 19, 1940 2,328,877 Gallagher Sept. 7, 1943 2,328,878 Gallagher Sept. 7, 1943 2,417,410 Gray Mar. 18, 1947 2,745,560 Gray May 15, 1956y