US3034662A - Cushioning mechanism - Google Patents

Description

D. WILLISON CUSHIONING MECHANISM 4 Sheets-Sheet 1 Filed March 5, 1956 INVENTOR. 301 410 W/ZZ/SO/V BY W ATTQPA/fy y 5, 1962 D. WILLISON 3,034,662

CUSHIONING MECHANISM Filed March 5, 1956 4 SheetsSheet 2 /0 l l 42d I 9 /4 32a I 20w;

ATTORNEY N mw Z VW m Q 6 Q g w ww D'. WILLISON CUSHIONING MECHANISM May 15, 1962 Filed March 5, 1956 wgln 'lllllllllllll y 1962 D. WILLlSON 3,034,662

CUSHIONING MECHANISM Filed March 5, 1956 4 SheetsSheet 4 3,034,662 CUSHIONING MEOHANISM Donald W1llison, Maple Heights, Ohio, assignor to National Castings Company, a corporation of Ohio Filed Mar. 5, 1956, Scr. No. 569,362 4 Claims. (Cl. 213-34) This invention relates to cushioning mechanism particularly adapted for use in railway vehicles.

In the operation of present day railway cars embodying conventional cushioning mechanism for absorbing the draft and bufiin-g shocks imparted to the cars, it is known that conventional cushioning mechanism or draft gear, as the mechanism is commonly known, is of inadequate cushioning capacity when the cars are subjected to unusually heavy bufling impacts. However, in order to increase the capacity of conventional draft gear, it is generally desirable to increase also the travel of the mechanism so that excessively high forces will not be applied to the gear and underframe structure of the car. There are, however, limitations on the amount of permissible travel of the mechanism, especially in draft, in order that interference will not occur between the head of the associated draft gear yoke and the forward portion of the car underframe structure.

Accordingly, while it is desirable to provide a long travel cushioning mechanism for bufling loads, it is generally necessary to substantially limit the travel of the mechanism in draft.

It is, therefore, an object of the present invention to provide a shock absorbing mechanism comprising a friction casing, a friction clutch and resilient means yieldingly opposing movement of the clutch inwardly of the easing, wherein the casing member embodies means to provide greater movement of the cushioning mechanism in buff than in draft.

Another object of the invention is to provide a shock absorbing mechanism for assembly between the front and rear stop lugs of a draft gear pocket comprising a friction casing adapted for longitudinal movement within the pocket, a friction clutch having sliding frictional engagement with the casing, resilient means yieldingly opposing movement of the clutch inwardly of the casing and a follower engaging the outer end of the clutch, the casing having abutment means thereon so constructed and arranged as to provide for greater movement in buff than in draft of the clutch and follower relative to the casing.

A more specific object of the invention is to provide a shock absorbing mechanism for assembly between the front and rear stop lugs of a standard draft gear pocket and between the front and rear abutments of a conventional draft gear yoke comprising a friction casing adapted for longitudinal movement within the pocket, a friction clutch having frictional engagement with the casing, resilient means yieldingly opposing movement of the clutch inwardly of the casing and a follower engaging the outer end of the clutch and adapted for engagement in one embodiment with the front stop lugs of the draft gear pocket and in another embodiment with the rear stop lugs of the pocket wherein the casing is provided with at least one longitudinally extending abutment arm adapted to pass through the follower and engage an abutment disposed exteriorly of the mechanism to limit the travel of the mechanism in draft while permitting substantially greater travel of the follower and clutch with respect to the casing in buff.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings in which:

FIG. 1 is a sectional plan view of the novel cushioning mechanism applied to conventional railway car underatet frame structure, the mechanism being shown in neutral position.

FIG. 2 is a sectional side elevational view of the mechanism shown in FIG. 1.

FIG. 3 is a vertical sectional view taken along line 3-3 of FIG. 1.

FIG. 4 is a plan view partly in section showing the cushioning mechanism compressed the maximum amount in draft.

FIG. 5 is a plan view, partly in section, showing the cushioning mechanism compressed to substantially the maximum amount in buff.

FIG. 6 is an enlarged isometric view of the friction casing and associated front follower of the mechanism shown in FIGS. 1 through 5, the follower being cut away to better illustrate the outer end of the casing.

FIG. 7 is a sectional plan view of a modification of the cushioning mechanism.

FIG. 8 is a sectional side elevational view of the modified mechanism shown in FIG. 7.

FIG. 9 is a sectional view taken along 9-9 of FIG. 8.

FIG. 10 is a plan view, partly in section, showing the modified cushioning mechanism compressed the maximum amount in draft.

FIG. 11 is a plan view partly in section showing the modified cushioning mechanism compressed to substantially the maximum amount in buff.

FIG. 12 is a sectional view taken along line 12-12 of FIG. 7.

Referring to FIGS. 1 through 6 of the drawings, there is shown the usual car sill construction 10-10, a. draft gear pocket 12 having rear stop lugs 14-14 and front stop lugs 16-16 and a draft gear yoke 18 which may be of any conventional type but which, in the embodiment shown, is an A.A:R. standard vertical plane horizontal key yoke.

The shank 20 of the car coupler is connected to the yoke by means of horizontal key 21 which extends transversely through slots 22 in the center sills 10-10 and side walls 24 of the striking casting 25. Slots 22 are of sufficient length that the ends thereof are at no time engaged by key 21 during draft or buffing movements of the coupler and yoke. Slot 26 in the coupler shank is of a slightly greater longitudinal length than the width of key 21, thus facilitating insertion of the key through the openings in the yoke and coupler shank.

The novel cushioning mechanism 28 broadly comprises a friction casing 30, front follower 32, resilient cushioning means 34 of any suitable type, and a friction clutch unit comprising a wedge block 36, friction shoes 38, and a spring plate 40.

The casing 30 is generally box-like in shape, comprising horizontally disposed, vertically spaced top and bottom walls 4.2 and 44 and transverse end wall 46 connecting the top and bottom walls. Wall 46 extends laterally a small amount beyond the edges of the top and bottom walls (FIGS. 1 and 6) to provide increased bearing area of the casing against rear stop lugs 14-14 and also to provide lateral guide surfaces 47 for directing movement of the casing between the car sills 10-10 during operation of the mechanism in draft. The forward portions of top and bottom walls 42 and 44 are also extended laterally outwardly to provide lateral guide surfaces 49 for similarly guiding the movement of the casing between sills 10-10., Intermediate the guide surfaces 47 and 4 9, a substantial clearance exists between the casing and the center sills as at 51, for a purpose to be hereinafter set forth.

The central portion of the rear surface of end wall 46 of the casing is offset forwardly to form a recessed yoke engaging section 48 for a purpose to be hereinafter set forth. It will be understood that wall 46 may be formed completely separate from casing 30, if so desired, without affecting the operation or functioning of the mechanism.

Disposed between the forward ends of walls 42 and 44 is an integral hollow friction portion 56 of hexagonal transverse cross section. Portion 50 is open at both its forward and rearward ends and is provided with fiat interior friction surfaces 50a which are preferably tapered inwardly of the casing in a rearward direction. Extending between top and bottom walls 42 and 44 adjacent the forward and rearward ends of friction portion are vertical strengthening ribs 52 (PEG. 6). The rearward section of casing 30, intermediate friction portion 50 and rear wall 46 houses the aforementioned resilient means 34.

In accordance with the invention, the casing 30 is provided with top and bottom abutment arms 42a and 44a which extend forwardly from the forward corners of the member. Arms 42a and 44a preferably are continuations of top and bottom walls 42 and 44, respectively, and are spaced from front stop lugs 16 when the cushioning mechanism is in neutral position, as shown in FIGS. 1 and 2. Arms 42a and 44a are adapted for engagement with front stop lugs 16-16 upon suflicient forward movement of easing member 30 to limit the travel of the cushioning mechanism in draft. It will be observed that in the embodiment shown arms 42a and 44a are rectangular in shape and are disposed substantially in vertical alignment. It will also be noted that the forwardmost of the aforementioned strengthening ribs 52 reinforces arms 42a and 46a against bending and shear forces.

Friction shoes 38 are provided with a pair of angularly disposed flat friction surfaces 53-53 on their outer sides for slidable engagement with corresponding friction surfaces Stia on the casing. Each shoe is also provided with a substantially flat inner wedge face 54 (FIGS. 1 and 2) sloping rearwardly toward the longitudinal axis of the mechanism and adapted to cooperate with a corresponding wedge face 57 on the wedge block 36. The rearward ends of the shoes have abutment surfaces 55 (FIGS. 1 and 2) adapted for engagement with the spring plate follower 40.

Wedge block 36 comprises a transverse front bearing face 56 engaging the rear surface of front follower "32 and rearwardly converging inclined wedge faces 57 in engagement with the aforementioned complimentary wedge faces 54 on friction shoes 38.

Spring plate member 40 comprises a transverse, generally rectangular base portion 58 and a forwardly extending abutment portion 58a. Portion 58a is disposed in telescoping relationship with friction portion 50 of the casing member and is in contact with the abutment surfaces 55 on the rearward ends of the friction shoes. It will be noted that base portion 58 extends laterally (FlG. 1) a suflicient amount to overlap the rearwardly facing surfaces 59 on friction portion 50 of the casing. It will [also be seen that due to the tapering of surfaces 501; on portion 50 of the casing, top and bottom shoulders 50b (FIG. 2) are formed thereon in overlapping relationship with top and bottom shoulders on spring plate member 40.

A forwardly extending retainer bolt 60 is secured at its rearward end to the front surface of plate 40. This bolt extends through a central opening in wedge block 36, its forward end being received in the enlarged recess 61. Bolt 60 is provided with nut 60a by means of which the parts of the cushioning mechanism are maintained in assembled condition for shipment as a unit or for easy insertion into the draft gear yoke and pocket of the car.

Disposed between spring plate 40 and rear wall 46 of the casing, intermediate top and bottom walls 42 and 44 is resilient cushioning means 34. Resilient means 34 serves to actuate the friction mechanism by opposing inward movement of the friction clutch with respect to casing 30 and also cushions the buffing or draft loads applied to the draft gear. Resilient means 34 is preferably but not necessarily formed of a group of rubber compression pads of the type disclosed in Willison-Spence United States Patent No. 2,686,667, granted August 17, 1954.

Front follower 32 comprises a transverse, generally rectangular base portion 62 for engaging the front stop lugs 1616 and a forwardly extending abutment portion 63 for engagement with the end surface of the coupler shank. In the embodiment shown, end surface 20a of the shank serves as the front abutment of the draft gear yoke 18 when the cushioning mechanism is assembled in the draft gear pocket of the car. The purpose of forwardly extending abutment portion 63 of follower 32 and the aforementioned recessed portion 48 of rear wall 46 of the casing is to move the coupler forwardly to allow greater clearance between the coupler horn (FIG. 2) and the front surface of the striking casting 25 to utlize the greater travel of the draft gear in buff.

In accordance with the invention, the lateral corners of base portion 62 of front follower 32 are cut away as at 64 (FIGS. 1, 2 and 6) so as to receive abutment arms 42a, 44a of casing 30 during relative longitudinal movement between follower 32 and the casing. Notches 64 are of suficient depth so as to provide clearance between abutment arms 42a, 44a and follower 32. In addition, the front abutment surface of portion 63 of follower 32 is relieved along its lateral extremities as at 65 (FIGS. 1 and 6) to aid in assembling the yoke and cushioning mechanism into the draft gear pocket of the car as will be hereinafter described. Relieved portions 65 preferably extend the full height of follower 32, the main body portion of which is of substantially the same height as casing member 30.

The assembly of the cushioning mechanism is preferably as follows:

The spring plate 40 is inserted between the top and bottom walls 42 and 44 of casing 30 and moved forwardly until base portion 58 engages friction portion 50 of the casing. Next, the resilient cushioning means 34 is subjected to an initial compressive load of approximately 3,000 to 5,000 pounds by suitable clamping means and is inserted between the rear surface of spring plate 46 and rear wall 46 of the casing. It will be understood that when cushioning means 34 is under the above initial compression, it will slip easily into place. Thereafter, the clamping means is removed and the cushioning means expands to hold spring plate 40 tightly against friction portion 50 of the casing.

Next, the friction shoes 38 and wedge block 36 are inserted from the front of the casing into the friction portion 50 with the front end of bolt 60 on spring plate 40 extending into the cavity 61 in the wedge block. A washer of any suitable crushable material is then placed on the front end portion of the bolt shank between nut 60a and wedge 36, after which the nut is tightened to maintain the friction clutch in assembled condition.

A compressive force is next applied to wedge member 36 by any suitable means, thereby moving the friction shoes 38 and spring plate 40 rearwardly to compress resilient means 34 a predetermined amount. Slugs of crushable material are then inserted between the rearwardly facing surfaces 59 on friction portion 50 of the casing and the base portion 58 of spring plate 40 to maintain resilient means 34 under a compression of approximately 8,000 to 10,000 pounds. The cushioning mechanism can then be conveniently stored, shipped as a unit, or inserted into a draft gear yoke for assembly into the draft gear pocket of a railway car.

To assemble the draft gear into the yoke and draft gear pocket of the car, the friction casing 36 with assembled friction clutch and resilient means is inserted laterally between the straps of the yoke 18 together with the front follower member 32. It will be understood that the longitudinal spacing between the rear stop lug engaging portions of the casing and the front surface of abutment portion 63 of follower 32 is less than the longitudinal spacing between the rear abutment surface 18a and the front surfaces 18b (FIGS. 1 and 2) of the yoke. Accordingly, the cushioning mechanism can be freely moved into place between the straps of the yoke.

The cushioning mechanism and yoke assembly may then be raised upwardly into pocket 12 of the car between the front and rear stop lugs 14 and 16. In this connection, the aforementioned crushable slugs between the abutment surfaces 59 on the friction portion 50 and the base portion 58 of follower 4G maintain the mechanism in a sufficiently compressed condition so that it slides easily into place between the front and rear stop lugs of the draft gear pocket. In addition, the aforementioned relieved portions 65 in the front abutment surface of forwardly extending portion 63 of follower 32 enable the yoke 18 to be moved suificiently rearwardly so that the front end 66 of its head portion clears the carrier portion 67 and associated wear plate 68 of the striking casting 25 during upward movement of the cushioning mechanism and yoke assembly into the draft gear pocket. A support plate 69 is then suitably attached to the underside of center sills '1010 to maintain the cushioning mechanism in operative condition.

Next, coupler shank 20 is inserted into the yoke head and the yoke connecting key 21, which is of conventional construction, is driven into place through the slots in the yoke and coupler shank.

A bufling force is then applied to the coupler, thereby moving follower 32 and the friction clutch assembly rearwardly and causing the slugs of crushable material to drop out from between friction portion 50 of the casing and spring plate 40, or to crush upon return of the parts to neutral position following the bufiing force. The crushable slugs in either whole or crushed condition will eventually drop down from the car through the aforementioned openings between the friction casing and center sills, intermediate the later guide surfaces 47 and 49 on the casing. It will be apparent that when the bufling force on the coupler is released, resilient means 34 expands, forcing front follower 32 tightly against front stop lugs 1616 and forcing casing member 30 tightly against rear stop lugs 14-44. With the cushioning mechanism in neutral position, resilient means 34 is subjected to an initial compression of approximately 7,000 pounds.

It will be understood that the crushable washer between nut 6011 and the rear surface of cavity 53 in wedge block 36 will crush out in service, its function merely to maintain the parts of the friction clutch in tight assembled condition prior to insertion of the cushioning mechanism into the yoke and draft gear pocket of the car.

Disassemhly of the draft gear is effected by removing support plate 68 and generally reversing the above described assernbly procedure.

The operation of the cushioning mechanism is as follows:

Under a pulling or draft load, the coupler shank transmits the load through yoke key 21 and rear surface 18a of the yoke to casing member 39 causing it to move forwardly after the initial compression of resilient means 34 and the static frictional resistance between friction shoes 38 and friction portion 50 of casing 39 are overcome. It will be seen that the engagement between the ront follower 32 and front stop lugs 16 prevents any forward movement of the friction clutch in draft. Accordingly, in draft the frictional resistance between the friction shoes 33 and the friction surfaces 500: of moving casing 30 together with the resistance to compression of resilient means 34 opposes the forward movement of the casing. As the draft force causes the casing member to move forwardly, abutment arms 42a and 44a on the top and bottom walls of the casing pass through the notched portions 64 in the lateral corners of front follower 32 6 and eventually engage front stop lugs 16 (FIG. 4) to limit travel of the mechanism in draft. In the embodiment shown, the maximum travel of the mechanism in draft is approximately 2% inches.

When a bufiing load is applied to the coupler, the rear abutment surface of the coupler shank transmits the load to front follower 32. When the bufiing load exceeds the initial compression of resilient means 34 and the static frictional resistance of friction shoes 38 against friction portion 50 of the casing, spring plate 40 is moved rearwardly. It will be clear that rearward movement of plate 40 is resisted by the sliding friction between the shoes and friction casing and by resilient means 34. It will be seen that the aforementioned engagement between the rear wall 46 of the casing and rear stop lugs 14 prevents rearward movement of the casing 30 in buff. It will also be seen that the aforementioned lateral guide surfaces 47 and 49 on the casing aid in stabilizing the latter against lateral movement during buffing operations. As the front follower 32 is moved rearwardly by the coupler, the abutment arms 42a and 44a on the top and bottom walls of the casing, pass through the notched portions 64 in the follower. Follower 3 2 continues to move rearwardly, as the buffing load increases, until engagement occurs between the rear surface 32a of the follower and the front surface 70 of the friction portion 50 of the casing as shown in FIG. 5 of the drawings. In the embodiment shown, the maximum travel of the mechanism in buff (FIG. 5) is approximately 3% inches.

Referring to FIGS. 7 through 11 of the drawings, there is shown a modified form of the invention. The cushioning mechanism is disposed between the usual car center sills 1010 and front and rear stop lugs 1616 and 1414. The yoke 18, coupler shank =20, yoke key 21 and striking casting 67 are of similar construction as the corresponding parts of the first described embodiment of the invention.

The cushioning mechanism of the modification broadly comprises a friction casing 70, a rear follower 72, resilient means 74, and a friction clutch comprising wedge block 76, friction shoes 78, and a spring plate The casing 7 6 is in the form of a hollow tubular member, open at its rearward end and closed at its front end by a transverse wall 82 which is extended laterally outwardly beyond the sides of the casing to provide front stop lug engaging portions 82a. Wall 82 intermediate stop lug engaging portions 82a extends forwardly to form an abutment portion 82b for a purpose to be hereinafter set forth.

The rearward portion '83 of casing member 70 in transverse cross section is hexagonal, its walls providing six interior friction surfaces 83a which are preferably tapered forwardly toward the longitudinal center line of the casing. The forward portion 84 of the casing is preferably of oval configuration and is adapted to house the resilient cushioning means 74. Longitudinally extending integral webs 86 are disposed on both sides of casing 70 to strengthen the latter and to provide guiding and stabilizing means during operation of the mechanism. At its open end, the casing is provided with three inturned lugs 87 (FIGS. 7 and 12) which are disposed around the interior periphery of the casing at alternate junctures of friction surfaces 83a. Lugs 87 are for use in maintaining the cushioning mechanism in assembled condition as will be hereinafter described.

In accordance with the invention, laterally spaced top and bottom abutment arms -88 extend rearwardly from the rearward extremities of the upper and lower walls of fraction portion 83 of the casing (FIGS. 7, 8 and 9). Arms 88 are adapted for engagement with the rear abutment surface 18a of the draft gear yoke 18 during operation of the gear. It will be observed that in the embodiment shown, the abutment arms are rectangularly shaped and are in substantially vertical alignment.

The friction shoes 78 are three in number and are similar to those of the first described embodiment, each presenting a pair of flat, angularly disposed friction surfaces 89 in slidable engagement with the two opposing friction surfaces 8311 on the interior of the casing. Each shoe is also provided with a substantially flat inner wedge face 89a (FIGS. 8 and 12) for engagement with a corresponding wedge face on wedge block 76. The forward ends of the shoes have abutment surfaces 8% (FIGS. 7 and 8) in engagement with the spring plate follower 80. Each shoe also has an outwardly facing, longitudinally extending slot 890 at the juncture of its outer friction surfaces 89. Slot 89c extends approximately half the length of the shoe, commencing at the rearward end of the latter and is adapted for cooperation with the aforementioned lug 87 on the friction casing to maintain the friction clutch and casing in assembled condition prior to insertion of the cushioning mechanism into the draft gear yoke and pocket of the car. This feature will be hereinafter more thoroughly discussed in connection with the assembly and operation of the mechanism.

Wedge block 76 is similar to the wedge block of the first described embodiment and comprises a transverse rear bearing face 90 engaging the front surface of rear follower 72 and three rearwardly converging inclined wedge faces 90a in engagement with the opposed complementary wedge f-aces 89a on the friction shoes.

Spring plate member 80 disposed forwardly of wedge 76 comprises a generally oval-shaped base portion 91 for engagement with the abutment surfaces 8% on the forward ends of the friction shoes. Member 80 has a rearwardly extending central portion 91a which is received between the forward ends of the friction shoes (FIG. 8) for positioning the shoes with respect to the member. A rearwardly extending retainer bolt '92 is secured to member 80. Bolt 92 extends through a central opening in wedge 76, which is enlarged as at 98 to accommodate a nut 92a on the end of the bolt. Bolt 9-2 together with the associated nut 92a serves to maintain the parts of the friction clutch in assembled condition prior to insertion of the cushioning mechanism into the draft gear yoke and pocket of the car.

Disposed between the front surface of spring plate 80 and the rear surface of front transverse wall 82 of the casing is the resilient means 74 which opposes inward movement of the friction clutch with respect to the easing to thus actuate the friction mechanism. The resilient means, as in the first described embodiment of the invention, is preferably formed of a group of rubber compression pads of the type disclosed in United States Patent No. 2,686,667.

Rear follower 72 is disposed between rearwardly facing casing abutment surfaces 99 and the rear stops 14-14 and comprises a transversely disposed generally rectangular plate adapted for engagement on its rearward side with the rear stop lugs 14-44 and on its forward side with the wedge block member 76. The rear surface of follower 72 is offset forwardly intermediate the rear stop lug engaging surfaces to form a recessed yoke engaging surface 94. The purpose of recessed surface 94 and the aforementioned forwardly extending abutment portion 82b of front wall 82 of casing 70 is to move the coupler forwardly to allow greater clearance between the coupler horn (FIG. 8) and the front surface of the striking casting to utilize the greater travel of the draft gear in buff. It will be noted that follower 72 extends the full height of casing 70 and has its front lateral corners relieved as as 95 (FIGS. 7 and 9) to lighten the member.

In accordance with the invention, the top and bottom sides of follower 72 are provided with centrally disposed slots or grooves 96 (FIGS. 7, 8 and 9) for receiving the abutment arms 88 on casing 70 during relative movement between the latter and follower 72. Slots 96 are of sufficient depth and width that no frictional engagement occurs at any time between follower 72 and arms 88.

The assembly of the modified cushioning mechanism is preferably as follows:

Resilient means 74 is inserted through the open end of easing member 70 and moves forwardly into engagement with front wall 82. Spring plate is then inserted into the casing in engagement with resilient means 74 and a compressive force or" approximately 8,000 to 10,000 pounds is applied to the plate by suitable means to compress the resilient means. Next, the friction shoes 78 are placed within the friction portion 83 of the casing with the lugs 87 on the casing extending into the slots 890 in the shoes. in this connection, the shoes are provided with crushable slugs which are temporarily disposed between the forward abutment surfaces 89d (FIG. 7) in the shoe slots and the lugs 87 to maintain the resilient means 74 under substantial compression. Wedge block 76 is then inserted into the open end of the casing with the front end of bolt 92 extending into the cavity 93 in the wedge block. A crushable washer of any suitable material is placed on the rearward end of bolt 92 and nut 92a is tightened against the washer to maintain the friction clutch in assembled condition. The cushioning mechanism can now be conveniently stored, shipped as a unit or inserted into a draft gear yoke for assembly into the draft gear pocket of a railway car.

To complete the assembly of the mechanism into the pocket of a car, the friction casing with the assembled friction clutch and resilient means together with the rear follower 72 are inserted between the straps of the yoke 18. The cushioning mechanism and yoke assembly may then be raised upwardly into pocket 12 of the underframe between the front and rear stop lugs 16 and 14. It will be understood that because the aforementioned crushable slugs between the friction shoes and the lugs 87 on the casing hold the resilient means in a substantial compressed condition, the cushioning mechanism is freely placed between the front and rear abutments 97 and 18a of the draft gear yoke and between the front and rear stop lugs of the draft gear pocket. A support plate 98 is then suitably attached to the underside of center sills i0-10 to maintain the cushioning mechanism in assembled condition.

Next, the coupler shank 20 is inserted into the yoke head and the conventional yoke connecting key 21 is driven into place through the slots in the yoke and coupler shank.

Successive buffing forces are applied to the coupler and released, thereby moving the casing 70 back and forth with respect to the friction clutch and causing the crushable slugs between the shoes and the lugs 87 on the casing to crush out. Resilient means 74 then expands, forcing rear follower 72 tightly against rear stop lugs 14-44 and portions 82a of casing 70 tightly against front stop lugs 16-16. The cushioning mechanism is then in neutral position and as shown in FIGS. 7 and 8 is held tightly between the front and rear stop lugs 14 and 16 of the draft gear pocket. In this position the resilient means 74 is under an initial compression of approximately 7,000 pounds.

Disassembly of the draft rigging is effected by removing support plate 98 and generally reversing the above described procedure.

The operation of the modified cushioning mechanism is as follows. Under a pulling or draft load the coupler shank transmits the load through yoke key 21 and rear surface 18a of the yoke to rear follower 72, causing it to move forwardly after the initial precompression of resilient means 74 and the static frictional resistance between friction shoes 78 and friction portion 83 of the casing are overcome. It will be seen that the frictional resistance between the shoes 78 and the friction surfaces 83a on the casing, together with the resistance to compression of resilient means 74 opposes the forward movement of the friction clutch and cushions the forces applied to the car coupler. As follower 72 is moved forwardly by the yoke, abutment arms 88 on casing 7% pass through the slots 96 in the top and bottom of the follower to engage the rear abutment surface 18a on the yoke (MG. and preclude further travel of the mechanism in draft. It will be noted that in draft the casing is held stationary by its engagement with front stop lugs 16. In the modified arrangement the maximum travel of the mechanism in draft, as shown in FIG. 10, is approximately 2% inches, which is substantially the same as the maximum travel in draft of the first described embodiment of the invention.

When a bufiing load is applied to the coupler, the rear surface a of the coupler shank transmits the load to front transverse wall 82 of easing member 70. When the bufling load exceeds the initial precompression of resilient means 74 and the static frictional resistance between friction shoes 78 and friction surface $341 on the casing 84, the latter is caused to move rearwardly thereby compressing resilient means '74 and producing sliding frictional resistance between friction surfaces 7811 on the shoes and surfaces 83a on the casing. It will be seen that during butting operations the friction clutch does not move but is held stationary by rear follower 72. As casing 70 moves rearwardly, abutment arms 83 thereon pass through the slots 96 in the top and bottom of rear follower 72 to engage abutment surface 18a on yoke 18. Thereafter, the casing and yoke move rearwardly as a unit until rearwardly facing abutment surfaces 99 (FIGS. 7 and 8) on the open end of the casing engage rear follower 72, as shown in FIG. 11. This represents the maximum travel of the mechanism in buff. The maximum travel of the draft gear in buff is 3% inches, which is substantially the same as the travel in buff of the first described embodiment of the invention.

While certain figures have been mentioned which are believed to be desirable for the initial compression of the mechanism, it should be understood that these particular figures are not essential to proper functioning of the draft gear.

From the foregoing description and accompanying drawings, it will be readily understood that the invention provides novel cushioning mechanism, adapted for assembly with conventional draft gear yokes between the front and rear stop lugs of a standard draft gear pocket and comprising a longitudinally movable friction casing having a plurality of abutment means thereon which allow greater travel of the mechanism in buff than in draft. It will also be understood that in the embodiments shown part of the abutment means comprises longitudinally eX- tending arms which are adapted to pass through an associated follower member to engage other abutment means disposed exteriorly of the cushioning mechanism to limit the latters travel in draft.

The terms and expressions which have been employed are used as terms of description and not of limitation and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. i i i A What is claimed is:

1. In combination with front and rear stops of a draft gear pocket, and a yoke having a rear front-facing abutment, cushioning mechanism disposed within the yoke and between the front stops and the rear stops; the mechanism comprising: a casing having rearwardly facing abutment surfaces; a rear follower disposed between said abutment surfaces and the rear stops; said mechanism having a neutral position wherein said follower is positioned against the rear stops, the casing is positioned against the front stops, and said abutment surfaces are spaced longitudinally of the pocket from the follower; said follower having a rearward facing yoke-receiving surface in longitudinal alignment with the yoke abutment; resilient means reacting with the casing and the follower to urge the mechanism into said neutral position; said casing, at said neutral position, having a pair of laterally spaced arms extending rearwardly beyond said casing abutment surfaces in longitudinal alignment with said yoke abutment and in lateral relation with said follower, and terminating in forwardly spaced relation with said follower yoke-receiving surface; said arms being spaced to allow movement of the follower lengthwise thereof into engagement with the casing abutment surfaces, and of a length disposing the rear ends of the arms rearwardly of said yoke-receiving surface when the follower and said abutment surfaces are engaged.

2. The combination of claim 1 wherein: said casing has a forward transverse wall for engaging the front stops; and said resilient means comprises a friction clutch in sliding frictional engagement with the casing and in abutting engagement with the follower.

3. The combination of claim 1 wherein: said follower has a pair of slots, one in each of opposite lateral surfaces, for receiving said arms.

4. In combination with rear and front stops of a draft gear pocket, and a yoke having a rear front facing abutment, cushioning mechanism comprising: a casing having arms projecting from its opposite side walls rearwardly relative to rearward facing abutment surfaces of the casing, in transversely ofiset relation with the arms, and in longitudinal alignment with said yoke abutment; a follower disposed between said arms for movement longitudinally of the pocket between said abutment surfaces and the rear stops; resilient means in the casing reacting between the casing and the follower to urge the mechanism to a neutral position wherein said follower is positioned against the rear stops in spaced relation with the casing abutment surfaces, the casing is positioned against the front stops, and the rear ends of the arms are located forwardly at a rearward facing yoke-receiving surface of the follower; said casing being movable rearwardly to en gage the follower in a position against the rear stops; said yoke being movable forwardly relative to the casing to engage and carry forward said follower until said abutment engages said ends of the arms.

References iterl in the file of this patent UNITED STATES PATENTS 1 ,069,933 Edahl Aug. 12, 1913

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