US1958490A - Draft and buffing mechanism - Google Patents

Description

May 15, 1934. w. H. MUssEY DRAFT AND BUFFING MECHANISM .Filed NOV. l5, 1950 5 Sheets-Sheet l 2o 2 N o n@ o o omv@ ,0 O

May 15, 1934- w. H. MussEY DRAFT AND BUFFING MECHANISM Filed Nov. 15, 1930 5 Sheets-Sheet. 2

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May 15, 1934- w. H. MussEY 1,958,490 I DRAFT AND BUFFING MECHANISM Filed Nov. 15, 1930 :s sheets-sheet s 4 l 4l 12v c 46 4 i zia es ii 345: i i I.' :E iii l' 4 4l Il Patented May 15, 1934 UNITED STATES PATENT OFFICE y DRAFT AND BUFFING RIECHANISM Ware Application'November 15, 1930,Serial No. 495,879

4 Claims.

The invention relates to shock absorbing mechanism for use in railway cars in which rubber spring groups provide the essential resistance element.

The principal object is to provide gear mechanism affording a high rate of absorption and cushioning with a minimum of gear travel.

A further and important object of the invention is to provide such mechanism for use in standard freight car underframes, and to so correlate the mechanism parts that all of the spring groups will function during buing operations,

and less than the whole number in draft.

The foregoing and other objects are attained by the mechanism illustrated in the accompanying drawings, in which' Figure 1fv is afragmentary view in plan, partially in section, of a car underframe end portion equipped with aA preferred embodiment of the shock absorbing mechanism of the invention;

Figure 2 is a vertical longitudinal section through underframe and mechanism taken on line 2 2 of Figure 1;

Figure 3 is a view similar to Figure 1, showing another embodiment of the invention in which a fourth spring group is introduced to provide additional bung capacity; f A v Figure 4 is a vertical longitudinal section taken on line 4 4, of Figure 3, showing further details of the tandem arrangement 'of the springs between the center sills of theicar underframe;

Figure 5 is a vertical sectional view transversely of the car taken on line 5 5, of Figure 3, showing in larger detail the draft yoke, side spring buffer and front spring beam assembly;

Figures 6 and 7 are similar views taken on lines 6 6, of Figure 1, and 7 7, of Figure 3, showing respectively one-half the rear spring beam and side spring buffer assembly, and a similar assembly with a fourth groupof springs in front of the beam between the center sills;

Figure 8 is a view in plan partially in section, of

f a third embodiment of the invention eliminating the rear spring beam of Figures 1 and 3, and substituting spring abutments projecting from the bolster center ller and bolster diaphragme; and Figure 9 is an enlarged fragmentary plan view of the rear spring beam and back stop connection with a portion thereof broken away toshow the method of assembling the dowel with beam and stop.

Due to the great amount of energy which must be absorbed. during buiiing operations or upon sudden changes in speed during train movement, considerable damage has been caused by the inertia of the cars and lading because of the failure of the shockabsorbing mechanism to properly dissipate the loads imposed within the limits of gear movement. In hopper and some other types of dump cars oflarge capacity but of limited length and restricted overhang, the space between bolsters and respective car ends is frequently too short to provide the necessary clearance to permit insertion and removal of standard draft gears of sufficient capacity. The friction gears heretofore used have been of a length proportioned to the required travel of the coupler and yoke .assembly, and to accommodate themit has been necessary at times to notch out the bolster center plate to provide room for the gear assembly to be dropped or mounted Withoutremoving the center plate or other parts riveted to the car structure.

Since to increase the travel of the gear would result in an objectionable increase of the slack movement between the cars of a train, it has been proposed to provide limited longitudinal movement of the car body with respect to the underframe parts supporting the shock'absorbing mechanism, but such method of mounting the car body involved considerable departure from accepted standards of car construction, is more expensive to build, and too heavy for general service application.

Since draft gears are supplied to provide a yieldable resistance not obtained from the car structure, it is necessary that the ultimate resistance of the gear be high if a minimum of the force of impact is to be transmitted to the car underframe; `For light impacts the velocities of the buiiing'cars are usually equalized before 90 the gears are compressed their full amount, but in impacts under forces tending to fully close gears of the friction type, the gear parts form virtually a metal column to transmit the remainder of the blow directly to the underframe. V

The metal to metal communication thus established between the closed'gear and underframe imposed abnormal strains upon the car structure and invariably resulted in damage to both carv and lading. I f the car structure were further stiffened to withstand the shocks imposed, the inertia of the car vwould be increased by the additional weight of the reinforcements applied, and the pay-load capacity of the car correspondingly reduced.

To overcome the di'iculties inherent in gears of the metal resilient and friction type, it is herein proposed to employ rubber resistance units of a type so designed and disposed in the gear organization as to eifectively protect the car 110 structure from blows considerably above the closing capacity of metallic friction draft gears, and to accommodate such units within the space available in existing cars, and render them interchangeable in some instances with the-gears now in use without change of any of the car parts.

. In the drawings, the gear of the invention is supported by center sills 10, of the car under'- frame, between bolsters 11 and the car end. At the bolster position, the sills are held spaced apart by a combined filter casting and gear back stop 12, the customarytop and bottom bolster cover plates 13 and 14, and center sill cover plate 15. For application to house cars, the gear portion betweenthe center sills is protected, and rendered accessible from inside'the car, by means of a cover plate 16, formed separately fromthe center sill cover plate 15, and which may be raised above the general level of the car floor 17, when steel floors are used, to accommodate upwardly protruding portions of the gear yoke 18, sufficient clearance being provided between the cover illler strips 19 for movement of the yoke longitudinally of the car.

As shown in Figures 1 to 4, inclusive, the yoke is connected to coupler 20 by draft keys 21 extending transversely through slots in yoke arms 22 and draft lugs 23. on the center sills 10 of the underframe, the slots 24 of the draft lugs-being of suillcient length to accommodate backward and forward movements of the key in draft and buing operations. The yoke indicated is particularly adapted, in the present embodiment of the invention, for use with couplers having swivel-butt drawbars 25 designed to equalize the pressure upon the yoke arms regardless of the angularity of the coupler with respect to the longitudinal center line of the car. The yoke illustrated is formed with upper and lower box portions 26 and 27 spaced vertically to accommodate spring beam 28 between them and provide abutments for drawbar 25 and front follower 29 of'the draft gear.

Because of the ability of rubber to function at a high rate of increase of resistance and its capacity for absorption of energy within short travel limits, -it becomes possible to arrange groups of such springs in parallel to restrict slack movement within practicable limits. Accordingly, a draft spring group 30 of rubber isarranged between the center sills and to the rear of front follower 29 within yoke 18, and similar groups 31 for bumng purposes, parallel to and outside the sills. As indicated in the several figures, the rubber spring units making up the various groups, comprise each a metal base plate 32, preferably circular in form, supporting a plurality of rubber rings 33 concentrically arranged upon opposite sides l of the base plates. Metal division plates 34 are introduced between the rubber spring units to insure proper distribution of energy to the rings 33, and prevent abnormal distortion thereof Iand the columns made up of these rings.

The springs of the draft group within yoke 18 are held between front follower 29, rear follower 35, and draft lugs 23, as best shown in Figures 1 to 4, and 8 of t e drawings, and the buffer spring groups 31 ou side the sills 10 are held between buffer heads 36 and back stops 37, respectively secured to front and rear spring beams 28 and 38. The beams are removably 'supported within slots 39 and 40 of the draft lugs 23 framed into corresponding slots of the sills tively,- by dowel 55 secured to the front spring as illustrated in Figures 1, 3, and 5, and provide tabutments for the springs during car moveme!! The buffer heads 36 are formed with securing jaws 41 spaced apart to receive front spring beam 28 between them and perforated for bolts 42 connecting with the beam. That portion of the head between the jaws 41 provides a bearing surface 43 for the rear face of the spring beam 28 andis preferably crowned, as shown in Figures 1 and 3, to at once insure positive contact and prevent lost motion between these members.

Extending rearwardly from opposite peripheral edges of the buffer heads is a pair of arcuate wings 44 conforming to the circular outline of the head and designed to interlock with a like pair of wings 45 projecting forwardly from the back stops 37 at an angle to the other wings, as best shown in Figures 3 and 5.

As indicated in Figure 3, the ends of wings 44 of the buffer head 36 overlap the heads on back stops 37 between wings 45, and the ends of Wings 45 overlap buffer heads 36 between wings 44 thereof as best illustrated in Figures 3 and 5. The heads 36 and '37 are chamfered as indicated in Figure 5 to insure proper guidance for the wings during builing operations. The edges of upper wings 45 and adjacent edgesof wings 44 are preferably horizontally disposed as indicated at 46 to prevent relative vertical displacement of the wings, and the lower edges 47 of wings 44 and adjacent edges of the lower wings 45 are vertically disposed to provide abutments to prevent relative lateral movement of the parts, so that the wings complement each other to form 110 guides and housings for the respective side spring groups 31 designed to provide a measure of protection for these springs and to support the heads in working alinement.

Both buffer and back stop heads and interposed spring groups 31 are held in assembled relation by bolts 48 extending parallel to sills 10 and having their respective heads 49 let into buffer heads 36 in position to be engaged by spring beam 28 during gear movement. The bolts are fitted with nuts 50 movable within column portion 51 of the back stops 37 under hurling, the nuts being removable to normally maintain the spring groups under compression between the beams 28 and 38. The back stops are also formed with jaws 52 extending rearwardly for connection with the rear spring beam 38, the jaws being spaced apart to provide a bearing surface 53 for the contiguous edge of rear spring beam 38 and perforated to receive bolts 54 connecting with the beam.

As will be obvious, the side spring assembly, comprising spring group 31, buffer head 36, and l back stop 37, when held together by connecting bolt 48, may be supported as a unit upon the protruding ends of the spring beams 28 and 38 and secured by the bolts 42 and 54, respectively. The spring assemblies are held in proper spaced relation outside the sills by the spring beams 28 and 38 which are held from displacement respecbeam at the longitudinal center of the car and entered in'socket 56 of the coupler shank, and similar dowels 57 on the rear spring beam entered in 4baclr stop casting 12 having openings 58, preferably tapered to correspond to the taper on the dowels. "The dowels are tapped into the spring beams to facilitate replacement in event of breakage or distortion. l

As before noted, the draft spring group 30 isA held by yoke 18 between draft lugs y23. 'mese 150 lugs are formed with front and rear stop shoulders 59 and 60 against which bear the front and rear followers 29 and 35, respectively. In the preferred embodiment, the distance between the stop shoulders is greater than between front and rear follower abutment faces, whereby the rear follower 35 is held normally spaced from the rear stop shoulders 60 on the lugs to permit a limited bodily translation of the draft spring group during bufling operations and in release movements vafter buiiing, without distortion.

The space 61 normally provided between rear followers and stops permits the initial application of buffing forces to the buffer spring groups 31 outside the center sills and subsequent applicationof load to the draft springs 30, so that the minor forces resulting from speed variations due to surging and lagging movements between the cars of a train in motion, are taken care of by the combined resistance of the buffer springs 31 only, and the relatively severe shocks of impact or brake applications will be resisted by all of said springs.

During release movement after closing, the gear parts will be restored to their normal positions by the expansive force of al1 of thesprings until the draft spring 30 has expanded to its normal compressed. condition within the yoke 18, whereupon continued expansion of buffer springs 31 will shift the draft spring 30, yoke 18, and associated coupler parts forward to their normal positions of rest. 4It should here be noted that the gear parts and capacity of buffer springs 31 are so proportioned in the mechanism that when the rear followers 35 contact with stop shoulders 60 on the draft lugs 23, the buffer springs will have been compressed an amount in excess of the normal compression of draft spring 30. By such coordination of draft spring travel and buffer spring capacity, the combined capacity of all the springs is utilized during the final closing and initial releasing movements of the gear.

The several spring groups comprising the draft and buffer springs 30 and 31 of the embodiments shown in Figs. 1 to,4, and 8, are each make up of an adequate number of rubber spring units designed to provided sufficient yield under the rapid building up of forces to absorb the shock of impact. Rubber ows sluggishly under high impact pressures and renders necessary the provision of a sufiicient number of rubber units in series to provide proper travel range for the gear in oder that the burden of the shock may be more widely distributed and the force translated into motion whereby the bufiing shocks will be absorbed within the gear before they can be communicated to the lading.

The capacity of the gear may be increased by the addition of a buffer spring group 62 arranged in tandem with draft spring 30. It may b e secured to the rearmportion of yoke 18, as best shown in Figs. 3 arid 4, the rear end of the yoke 18 being enlarged toprovide a broad abutment 64 for the spring'group. The opposite end of the spring is seated against follower 63 held to the yoke by bolt 65 fittedwith securing nut 66 movable within recessA 67 in the yoke during buffing action.

It will be noted that the mere addition of the spring group 62'in parallel with others of the gear, operates only to increasethe capacity of the gear without affecting the ,travel range unless the number of rubber units in series-in the several comprising a relatively larger number of rubber springs in series are adapted for use with springs having a smaller number of rubber units in series.

As shown in Fig. 3, the space between wings 44 and 45 normally occupied by one or more of the spring units of the contained series, is made to accommodate a filler block 68 designed to provide an abutment surface for one end of the spring group. As in the case of thesprings, the ller-is perforated and strung upon the respective connecting bolt 48. Certain elements are thus rendered interchangeable for use in gears of different capacity and travel range, whereby the necessity for providing housings of different sizes for springs of varying yield and capacity, is avoided.

To permit unimpeded forward movement of the yoke 18 under draft, the yoke metal at abutment 64 is formed as indicated at. 78, to clear adjacent stop shoulders 60v on the draft lugs 23, so that the supplemental buffer spring 62 and its follower 63 secured to the yoke will be shifted bodily and away from the rear spring beam 38 against which said follower normally abuts.

To prevent undue sagging of spring and follower and possible loss thereof in transit, these parts are protected by an underlying plate 69 removably secured to the underside ofthe center sills' 10 by bolts 70. The yoke 18 between the sills is primarily supported upon the front spring beam 28, and heldin alinement by underlying plate 71 secured to the underside of the center sills -10 by bolts 72, as best shown in Figs. 3, 4, and 5.

' Normally, the beams 28 and 38 are loosely supported in slots 39 and 40 of the center sills and carry only the weight of buffer spring groups 31 and respective housings. It will be noted that the front beam slots 39 in draft lugs 23 and center sills are long enough to permit necessary travel of the beam 28 duringbufling operations, while the slots 40 at the rear of the gear are of a length sufiicient only to receive the rear spring beam 38 over the retaining dowels 57 in assembling the gear, since the rear spring beam is otherwise immovable during bufling operations, providing as it does a common abutment for spring groups 31 and 62. 'I'he front and rear beams find substantial bearing against respectively adjacent faces 73 and 74 presented by the draft lugs 23 and back stop casting 12 and contiguous under frame members 10 and 11.

The capacity of rubber springs to swiftly cushion shocks of impact within a comparatively short travel range, permits the application of relatively wide areas of springs transversely of the car, and spring groups of less free height than the diameter of the springs, thereby insuring the stability of the gear as a wholeand rendering possible its installation in freight cars having limited space between holsters and adjacent car ends, as before outlined. y

In practice, the gear is assembled by first arranging the draft spring group 30 within the yoke 18 in its initial compressed condition when the three spring gear of Figs. 1 and 2 is used. In the case of the four spring gear of Figs. 3 and 4, the center buffer spring group 62 is first secured to the yoke and adjusted to desired initial compression which in this case would be the same as that of side groups 31, after which the draft spring group 30 is inserted within the yoke, and the whole positioned between the sills 10. The spring beams 28 and 38 are then entered in their birding impact.

ready for operation. y

The retention of the rear spring beam 38 in the assembly is preferred since by the use of the beam the stress of bufng may be concentrated at the center sills 10 which alford the greatest sectional area in the underframe structure for stresses longitudinally imposed and avoids eccentric loading of such members under impact. Occasionally, however, conditions of construction are such as to render expedient the elimination of the spring beam, in which event the arrangementmay take the form shown in Fig. 8, in which embodiment the spring group 62 bears directly upon bolster filler and backstop 12 while the side spring groups 31 find abutment against brackets secured to andconnecting bolsters 11 and adjacent center sill members.

By such arrangement, a considerableportion of the stress of buing is distributed thru the bolster to the car side, and the distance between holsters and adjacent car ends shortened whereby gears of very high capacity may be accommodated within the limited space thus available. In such construction, the spring groups 31 would be assembled von the car since the brackets 75 are iixed members of the car structure. The spring groups are secured between buffer heads 36 and the brackets by stud bolts 76vtapped into the buffer heads and adapted to initially compress the springs for purposes hereinbefore outlined. In-

stead of the annular spring retaining anges 77 on heads 36 and brackets 15, housing wings of the Ktype indicated in the other-embodiments may be substituted. v

From the foregoing, it will be noted that all of the'spring groups function during bufling operations, and but one of them, group 30 within yoke 18, is utilized for draft purposes. This results from the inability of the front spring beam 28 to move forward under pull of the coupler 20 due to abutment thereof against stop shoulders 73 of the draft lugs, whereby the buffer` spring groups 31 outside the sills and attached to such beams are not subjected to draft movement and function only upon rearward travel of beam 28 under What I claim isz- 1. The combination with spaced longitudinal sills of a car underframe, of a pair of spring abutrubber draft spring carried by said yoke member l 4and operatively engaging the adjacent 'of said beams, said adjacent beam being movable during builing operations only and independently of said other beam, said last noted beam being relatively stationary and mounted rearwardly ofthe zone of yoke movement.

2. The combination with spaced longitudinal sills of a car underframe, of parallel rubberl draft and buffer springs arranged respectively between and outside of said sills, front and rear spring abutmentv beams extending through the sills forwardly of and at the rear of said springs, means connecting said beams and buller springs independently of said sills, and a yoke member terminating with its rear end in front of said rear beam and slidably mounted on the other of said beams and operatively supporting said draft spring, said yoke supporting beam being movable with said yoke member during bulng operations only.

3. The combination with spaced longitudinal sills of a car underframe, of parallel rubber buffer springs kdisposed between and outside of said sills, spring abutment beams extending thru the sills and connecting the outer of said springs, a draft spring arranged in tandem with the buffer spring between the sills, and a draft yoke member slidably mounted upon one of said beams and operatively supporting said draft and intermediate buffer springs, said intermediate buffer spring being movable bodily with said yoke.

4. The combination with spaced longitudinal sills of a car underframe, of spaced spring abutment beams extending thru said sills, rubber buffer springs parallel to and outside of the sills supported between said beams, and collapsible housings for said springs having buffer head and back stop sections respectively secured to adjacent beams and provided each with intermediate spaced guide wing portions extending between said buffer head and backstop sections and adapted for mutual guidance and support, said buffer head and back stop sections being recessed horizontally and vertically to respectively prevent vertical and lateral displacement of said wings. Y

WILLIAM H. MUSSEY.

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