US2337396A - Car truck - Google Patents

Description

R. LEPPLA' Dec. 2l, 1943.

CAR TRUCK F1163 May 23, 1941 1 -2-.. I.. Vgl..

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Patented Dec. 21, 1943 Y CAR TRUCK Rudolph Leppla, Davenport, Iowa, assignor, by

mesne assignments, to

Pittsburgh, Pa., a corporation of Corporation, Pennsylvania McConway & Torley Application May 23, 1941, Serial No. 394,865

2 Claims.

This invention relates to railway car trucks, and more particularly to an improved spring support for the bolster. In railway freight cars it is necessary that the truck springs have the strength and stillness to carry the maximum load and that the deflection of the truck springs be so limited that there will not be suicient difference in the heights of the couplers of a loaded and an empty car to interfere with the action of the couplers. In general freight service the railroads have considerable difficulty by reason of damage to goods carried in lightly loaded cars by reason of the inadequate cushioning action of the heavy cushioning springs.

Diiferential cushioning spring arrangements are disclosed and claimed in my copending application, Serial No. 381,428., filed March 3, 1941. The present invention is directed to application ofthe dilerential cushioning principle to a particular type of truck and to certain improvements.

It is the object of this invention to provide cushioning springs which have a relatively large deflection when subjected to light loads but which have different deflection characteristics when subjected to loads greater than a predetermined amount, and in which the total deflection is not sufficient to cause diii'iculty in coupling empty cars to heavily loaded cars.

With the above and other objects in view thev invention may be said t comprise the truck as illustrated in the accompanying drawing hereinafter described and particularly set forth in the appended claims, together with such variationsl and modifications thereof as will be apparent to one skilled in the art to which the invention pertains.

Reference should be had tothe accompanying drawing forming a part of `,the specification, in which:

Figure 1 is a side elevation of a truck embodying the invention, portions of the side frame, bolster and spring plank being broken away and shown in section;

Fig. 2 is a section taken on the line indicated at 2 2 in Fig. 1, portions of the spring plank and spring cap being broken away to show the structure of underlying parts;

Fig. 3 is a section taken on the line indicated at 3-3 in Fig. 1; and

Fig. 4 is a transverse vertical section showing a modified form of bolster spring.

Since the side frames of the truck and the supports for opposite ends of the bolster are identical, the accompanying drawing Shows the con- (Cl. 10E-197.1)

struction at one side of the truck only, it being understood that this construction is duplicated at the opposite side of the truck, as is usual in car truck construction.

Referring to the accompanying drawing the side frame, indicated generally by the numeral l, has an upper compression chord 2 and a lower tension chord 3 which connect the end portions of the frame in which journal boxes i are provided. The upper and lower chords 2 and 3 are connected intermediate their ends by integral upright columns 5 which are spaced apart to provide a central opening in which a suitable car body supporting member, such as bolster 6, is guided for vertical movement. The bolster 6. and side frames l are held against relative tilting movement by suitable means such as guide iianges l on the bolster which overlie the inner and outer sides of the columns 5.

In the device of the present invention thebolster 6 is supported upon two superimposed sets. of cushioning springs, the upper cushioning springs 8 being interposed between the bolster 6 and an intermediate supporting member such as a spring plank lil, and the springs 9 being interposed between the spring plank I3 and the lower chord 3 of the side frame. Various forms of springs may be employed; for example, the springs between the spring plank and bolster may be in the form of a group of coil springs 8, as shown in Figs. 1 to 3, or in the form of an elliptic spring Il, as shown in Fig. 4. When coil springs are employed such as shown in Figs. 1

to 3, suitable spring positioning plates l2 may' bolster andA be provided upon the underside of the upon the spring plank.

The portion of the lower chord extending across I the bottom of the side frame opening is preferably of channel form having a bottom web=|3 and upwardly extending side anges I4. The iiangesI I4 may be extended laterally at their upper edges to stiffen the channel and provide seats l5 for limiting the downward movement of the spring plank Il).

A spring cap It is supported upon the springs 9 and guided for vertical movement in the side frame. The spring cap IS supports the end of the spring plank l@ and is preferably rigidly attached to the spring plank by suitable means such as welding. If a cast spring plank is employed, the cap IS may be cast integrally with the plank. The spring cap I6 is provided with guide portions at the ends thereof which are provided by upwardly extending flanges Il and depending anges i8 which provide guide faces of substantial width and depth which cooperate with the inner faces of the guide columns 5 and which add considerable strength to the cap. The cap I6 is also provided with spaced depending flanges IG which are disposed at right angles to the anges I8 and which are disposed within the flanges Hl of the tension chord 3. The end flanges i8 form webs connecting `and stiening `anges i9 at the ends of the spring cap and a similar stiiening web 2) is provided between the intermediate guide flanges I9. iianges I8 and I9 and the cross web 20 provide spring pockets which receive the upper ends of the springs 9. The spring ,cap i5, with its guide flanges coacting with the columns 5 and tension chord flanges I4, serves to keep the truck square and prevent the side frames from changing their spacing when side thrusts are imposed on the trucks. The upper portions of the side frames being held in position by the bolster and the lower portions thereof being held in position by the spring p'la'nlcvthe `side frames are prevented from tilting on `the axles. The spring cap I6 is provided with depending flanges 2| along its side edges which, when the cap is seated on the bottom chord, provide additional bracing for the side frames. The springs 9, which are housed within the tension Achord channel and the cap I6, may be positioned in the bottom of the channel by suitable lugs or ribs 22 and 23 which may be formed integrally with the web i3.

In order toprovide a spring arrangement which will be suitable for light loads as well as heavy loads, it is contemplated that the bolster springs 8 will be of standard design; i. e., they will be stiff enough to adequately cushion and support the'maximum loadrthe car is intended to carry. The springs 9, on the other hand, will have more' deflection per unit of load than the springs and will be vlight* and flexible enough to adequately,

impacts transmitted to the car truck through the truck wheels may cause bumping of the spring plank upon the bottom chord, suitable sound reducing pads 25, which may be formed of rubber and fabric, may be provided on the seats I5.

It is to be understood that variations and modications of the specific devices herein shown and Y described for purposes of illustration, may be The depending cushion alight load. Thelighter springs 9, how'- ever, are permitted only a relatively small range of movement, the free length of these springs being 'such that the spring cap I6 will rest upon the seatsfl5 and the springs 9 will be stopped ofi when a' predetermined load is imposed upon theA springs. 'The dinerential cushioning action due to 'the stopping off of the weaker spring provides ample Ydeiiection for effectively cushioning light loads without anv increase in total deflection throughoutlthe range of loads sufficient to'interfere with the action of the car couplers.

l'n order' to dampen oscillations, a snubber, such as the snubber 24, may be advantageously .em-

ployed, preferably in connection with the springs which cushion the heavier loads. The snubberV 24, which is shown in connection with the springs 8; is of conventional construction and is there" fore not described in detail. Y

Since under certain conditions of loading thev made without departing from the spirit of the invention.

What I claim is: Y

1. A car truck comprisingside frames having spring supports, lower cushioning springs mounted on the spring supports of each side frame, an intermediate vertically movable supporting member seated upon the cushioning springs of each side frame, upper cushioning springs mounted upon said supporting member, a vertically movable -car -body supporting member extending across the space between the side frames and seatedupon the upper cushioning springs, means for limiting the downward movement of one of said supporting members with respect to the supports for the cushioning springs upon which it is seated to stop off the latter springs, said latter cushioning springs being capable of adequately supporting and cushioning a lightly loaded car body and said limiting means being operable When said latter springs are subjected to the pressure of an excessive load, the other set of cushioning springs being capable of adequately supporting and cushioning a car body having its maximum load and both sets o f springs being normally operable, and snubbers interposed between the last mentioned supporting member and the supports forthesprings upon which it is seated.

2. -A car truck comprising side frames having spring supports, lower cushioning springs mounted onthe spring supports of each side frame, an intermediate vertically movable supporting member seated upon the cushioning springs of each side `frame, upper cushioning springs mounted upon said4 supporting member, a vertically movable car body supporting member extending across the space between the side frames and seated upon the upper cushioning springs, the lowercushioning'springs being capable of adeu quately supporting and cushioning alightly loaded car body and the upper cushioning springs being `relatively heavy, and capable of adequately sup porting and cushioning a car body having its maximum load, said upper and lower springs being normally operable, means for limiting the downward movement of theV intermediate supporting member with respect to the side frames when the lowerI springs are subjected to the pressure of an excessive load, and snubbers interposed between the car body supporting member and the intermediate supporting member.

RUDOLPH LEPPLA.

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