US2317391A - Car truck - Google Patents

Description

April ,27, '1943.

R. LEPPLA CAR TRUCK Filed April 3. 1941 erf@ 6%# L? Rh E. www u 1 R ,m

Patented Apr. 27, 1943 UNITED STATES PATENT OFFICE mesne assignments, to McConway & Torley Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Application April 3, 1941, Serial No. 386,702

(Cl. 10S-190) Claims.

This invention relates to car trucks of the socalled swing motion type in which the bolster is supported upon springs carried by supporting members pivotally suspended from a transom eX- tending across the space between the truck side frames, and particularly to trucks for freight cars designed to carry heavy loads.

The present invention relates particularly to trucks of the type described in my copending application, Serial'No. 382,955, filed March 12, 1941, in which the truck is provided with superposed sets of cushioning springs, one set interposed between the bolster and transom and the other set interposed between the transom and side frame; and in which means is provided for stopping o" the springs of one set before the springs of the other set are fully compressed in order to provide a car which is easy riding when lightly loaded, and to provide an effective spring cushion for the car through a wide range of loads.

The present invention has for its principal objects to provide improved mounting for the transom in the side frames of the truck and to provide an improved spring support for the transom.

With the above and other objects in View, the invention may be said to comprise the car trucks as illustrated in the accompanying drawing, hereinafter described and particularly set forth in the appended claims, together with such variations and modifications thereof as will be apparent to one skilled in the art to which the invention pertains. Reference should be had to the accompanying drawing forming a part of this specification, in which:

Figure l is a fragmentary side elevation of a truck embodying the invention, portions of the side frame and transom being broken away and shown in vertical section;

Fig. 2 is a fragmentary top plan view showing one end of the transom and the portion of the side frame in which the end of the transom is mounted; and

Fig. 3 is a section taken on the line indicated at 3-3 in Fig. l.

In view of the factthat the side frames of the truck and the supports for opposite ends of the transom, spring plank and bolster are identical, the accompanying drawing shows the construction at one side of the truck only, it being understood that the construction shown is duplicated at the opposite side of the truck as is the usual practice in car truck constructions.

Referring to the accompanying drawing, the

truck of the present invention has a bolster A upon which the car body is supported, a spring plank B which carries supporting springs upon which the ends of the bolster A rest, a transom C from which the spring plank is pivotally suspended, and side frames D in which the ends of the transom are slidably mounted.

Each side frame D has an upper compression chord I and a lower tension chord 2 which connect journal boxes 3 located at opposite ends of the frame. The chords I and 2 are connected intermediate their ends by spaced guide columns 4 which provide a central opening in the side frame midway between the ends thereof. The guide columns 4 have widely spaced vertical guide portions 5 adjacent the bottom chord 2 and vertical guide portions 6 at their upper ends which are offset inwardly with respect to the lower guide portions 5, providing a transom receiving space at the top of the opening considerably narrower than the space between the guide portions 5 of the columns. The upper and lower guide portions 5 and E of the columns 4 are connected by upwardly converging inclined portions 1. The bottom chord 2 is curved throughout its length so that the portion thereof between the lower end portions 5 of the columns is downwardly arched. The chord 2 has a bottom web 8 and the portion of the chord between the lower ends 5 of the columns 4 is in the form of an upwardly opening channel consisting of the bottom web 8 and upright side flanges 9. The flanges 9 have upwardly extending guide portions I0 adjacent the lower guide portions 5 of the columns and between the projecting portions IB and throughl out the major portion of the width of the opening the anges 9 have horizontal top edges II which provide transom seats.

The transom C has two crossbeams I2 which extend across the space between the side frames D and which are spaced apart to receive the bolster A between them. The bolster A has end portions guided for vertical movement between the crossbearns I2, the crossbeams having vertical inner faces I3 which serve as guides for the bolster. The crossbeams I2 are rigidly connected at their ends by members I 4, which are the upper crossbars of rectangular transom guide frames which slidably t within the side frame openings. Each transom guide frame has vertical side bars I5 and a base member I6 connecting the lower ends of the side bars. The top bar I4, side bars I5 and base member I of the transom guide frames provide a substantially rectangular window in the transom end frame widened base portion for the transom guide frame which is guided between the lower vertical portions 5 of the guide columns.

flanges I0 of the bottom chord. The'transom end frames are also provided with depending iianges on the base portion I6 which overlap the anges 9 of the bottom chord.. The shoul-A ders I3, guide flanges I 0 and `flanges 25) guide the transom in the side frame and cooperate to hold the transom against angular movements with respect to the side fra-mes. l

Withinthe channel portion or the bottom chord, there is mounted a semi-elliptic leaf spring AZI which Ahas-a central Aband 22 which is seated between lugs 23 on the bottom web2). The opposite-ends of the leaf spring; are curvedupwardly away from the web 8 and provided with end portions 24'which bear against the `bottoms of the projections Ivto yieldably'support the transom. Thespring 2I is housed within the channel portion of thebottom chord 4and normally supports thetransom withits base portion I6 spacedabove the top edges II of ltheV bottom chord anges. However, when a predetermined load risimposed upon the'transom; the spring `2I is compressed suiiciently to permit the transomto seat upon the bottom'Y chord. The spring plank Bis suspended from the transom Cp by means of links 25 Awhichare vconnected at theirupper ends to the crossbeams I2 by pivots 26 and at their -lower ends Ato the spring plank B by pivots 21. e Cushioning springs of any suitable typemaybe interposedbetween the spring plank B and-,the bolster A.V As herein shown, the spring support for thebolster may be in the form of a nest ofcompression coil springs 28. They strength and deiiection characteristics of the spring.2| .are such that .when the transom is placedupon the spring thetransom will move downwardly until the projections I9 -are positioned in the spaces between Athe guide `flanges IU. Suflicient clearanceis providedv between the projections I9 and the inclinedfportion 1 of ,the guide'columns to permitlthe transom to be lifted'to a position in whichthe projections IS are cle-ar of Vthe flanges I0 Vto permit-easy placement orremoval'of the side frames. Y

By providing a spring 2I ofthe proper deflection characteristics,V the seating of the transom on the bottom chordcan be made tooccur under any desiredlo'ad, which in any case will occur beforethe crushing point or safe stress limit of thespring hasfbeen reached.A

When the load upon the ftruck is not suiiicient to compres-s the springs2I into the channels of the bottom chords and seat the transom on the bottom chords, the total deection of the car body is the sum of the compression of the springs 2| under the given` load andthe compression of the springs 28 under 'the same load. The two sets of springs thus provide a car body support which permits the bolster and car body to have a greater rangeof movement and provide a more yieldable The projections I9 are received between.the projectingV guide` cushion than would be provided by either set of springs alone.

This increased deiection is Very advantageous in that it provides easy riding qualities in a lightly loaded car. For example, if the bolster cushioning springs are designed to provide effective cushioning action with a heavily loaded car, the

combined action of the springs 2I and 28 may provide an effective cushion for the car when empty or lightly loaded.

The bolster and transom cushioning springs can be readily removed and replaced with other springs of different capacity. For example, if it is desi-red to employ a car for carrying loads lighter than .those for which the trucks were originally designed, the transom springs, or both the transom'andbolster springs may be replaced with springs having the capacity and amplitude of movement suitable for the lighter load.

The transom springs 2I are preferably more yieldable than the bolster springs, but may .if .desired be of sufcient stiffness 4to allow for some deflection Vbeyond that resulting from a fully loaded car. Under these conditions 'the transom cushioning'springs do most of the 'cushioning and the relatively stii'er bolster supporting springs have a snubbing effect when the transom seats on the side frames because of excessive impacts. Also, vibrations are damped by reason of the differences in the periods and amplitude ofthe vibration of the two sets of cushioning springs.r

The side frames are easilyremoved by simply jacking up the transom to its uppermost positiona in whichv position the projections I9 are clearrof the flanges ID and the iianges 20 are clear of the nanges 9. Y Y

To prevent the truck from getting out. of square, there must be close cooperation-between the ,side frames and the members which connect them. In a truck of the present inventio-n, the, depend,- ing flanges 20 together with the projections I9 cooperate with the side frames to prevent angular movement between the transom and theside frames in a horizontal plane. Because of the fact that the projections I9'are widely spaced, considerable clearance can be 'allowed between these projections and the guide iianges Ifso as to permit free vertical movement of the transom without permitting any substantial horizontal angling.

It is to be understood that variations and modications of the specific device as herein shown and described for purposes of illustrationmay be made without departing fromthe spirit of the invention.

What I claim is:

1. In a car truck, a side frame havingatop chord, a bottom chord and spaced guide columns forming a central openingin the frame, the portion of the bottom chordbetween said columns being in the form of an upwardly opening channel with a web which curves upwardly from the center toward the ends of the chord and, upright side ilanges which have horizontal. topv Vedges throughout the major portion of the space'between the columns and which .have upwardly projecting guide portions adjacent the columns, a semi-elliptic leaf spring having a central portion seated upon the web of the bottom chord substantially midway between the columns and end portions curved upwardly away from said.

the end portion of the transom having portions extending into the spaces between the upwardly projecting portions of said flanges and resting upon said springs and a fiat seating portion engageable with the top edges of said flanges.

2. In a car truck, a side frame having a top chord, a bottom chord and spaced guide columns forming a central opening in the frame, the portion of the bottom chord between said columns being in the form of an upwardly opening channel with a web which curves upwardly from the center toward the ends of the chord and upright side anges which have horizontal top edges throughout the major portion of the space between the columns and which have upwardly projecting guide portions adjacent the columns, a semi-elliptic leaf spring having a central portion seated upon the web of the bottom chord substantially midway between the columns and end portions curved upwardly away from said web and terminating adjacent the columns between the upwardly projecting portions of said flanges, and a transom having an end portion guided for Vertical movement in said opening, the end portion of the transom having portions extending into the spaces between the upwardly projecting portions of said flanges and resting upon said springs and a flat seating portion engageable with the top edges of saidY anges, said transom having shoulders engageable with the inner sides of said columns and depending flanges overlapping the anges of the bottom chord.

3. In a car truck, a side frame having a top chord, a bottom chord and spaced guide columns forming a central opening in the frame, said columns having upper vertical guide portions, lower vertical guide portions offset outwardly with respect to the upper portions and downwardly diverging portions connecting the upper and lower guide portions, the portion of the bottom chord between the lower ends of the columns being in the form of an upwardly facing channel having a web which is downwardly arched between the columns and upright side anges, said flanges having guide portions projecting upwardly adjacent the lower ends of the columns and horizontal top edges between said projecting guide portions, a semi-elliptic leaf spring seated upon said web midway between the columns and having its opposite ends positioned between the upwardly projecting guide portions of the anges, and a transom having shoulders engageable with the upper vertical portions of the guide columns and an end portion guided for vertical movement between the upper portions of the columns, said end portion or" the transom having lateral projections extending into the spaces between the guide portions of said flanges and resting upon the ends of said spring, said end portion of the transom having a flat bottom adapted t0 seat upon the anges of the bottom chord when the transom is subjected to a predetermined load.

4. In a car truck, a side frame having top and bottom chords and spaced guide columns connecting said chords, the portion of the bottom chord between said columns being in the form of an upwardly opening channel, a transom having an end portion guided for vertical movement between said columns, a bolster yieldably supported upon the transom, a semi-elliptic leaf spring having its central portion seated in said channel and its opposite end portions supporting the end portion of the transom, and interengaging seats on the transom and bottom chord to limit the compression of said elliptic spring.

5. In a car truck, a side frame having top and bottom chords and spaced guide columns connecting said chords, the portion of the bottom chord between said columns being in the form of an upwardly opening channel, a transom having an end portion guided for vertical movement between said columns, a bolster yieldably supported upon the transom, and a semi-elliptic leaf spring having its central portion seated in said channel and its opposite end portions supporting the end portion of the transom, the ends of said spring being deflectable into the channel of the bottom chord to permit the end portion of the transom to seat upon said bottom chord.

RUDOLPH LEPPLA.

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