US2446506A - Snubbed bolster car truck - Google Patents

Description

` A Aug. 3, 1948.

c. D. BARRETT ET AL SNUBBED BOLSTER CAR TRUCK '3 Sheets-Sheet l Filed Aug. 8, 194e Aug. 3, 1948. c. D. BARRETT ET AL [2,446,506

SNUBBED BOLSTERAR TRUCK Filed Aug. 8, 194e l 5 sheets-sheet 2 Ffa L Ffa@ 1.1% mi 20 M WL.. 22 29 @kT-ii I 5 l 212 l ]7- ,4N NTT @w-aj? Aug. 3, 1948. c. BARRETT ET AL i 246,506"

SNUBBED `BOLSTER CAR TRUCK 5a y@ 0, T l

ATTORNEYS.

f l Y .mm

Patented ug. 3, 1948 si ori-ic s;

SNUBBED HOLSTER CAR TRUCK Charles D. Barrett and Binaries R. ff'

tehead, y

l fllaims. (Ci. M15-197) involving friction means used in association with springs for controlling the relative movement between'the ends of the bolster and the side frames. i

Heretofore it has been proped to employ wedge elements in combination with springs to provide increased friction between the 'ends of the bolster and thecolumns of the side frame between which the bolster is guided in its vertical movement. -In certain trucks of this character the spring pressure and the friction between bolster and side frame remain constant regardless of the load on the main carrying springs which support the bolster and the car. In others, the arrangement of springs and wedges is such that the friction between bolster and side frame .is variable and is caused to increase as the load on the main springs is increased.

because it has the proper degree of friction for dampening or snubbing the harmonic movement of the bolster. But it possesses poor riding qualities when the car is heavily loaded because the dampening or snubbing action is then insumcient. Moreover, if the pressure on the control springs is increased to provide enough friction to properly dampen or snub the harmonic movement, the friction becomes too high for an empty car.

In trueksof the second type mentioned herein y the wedge spring pressure and, therefore, the friction between side frame and bolster increases directly with the load in the car and is very much higher in a loaded car than in an empty car. It

is a simple matter with such a construction to make the friction high enough for proper dampening for a. loaded car, but in such event as the load is decreased the friction falls od and is in- --sumcient to control properly an empty car.

Hence trucks of this type possess good riding qualities with a heavily loaded car and poor riding qualities with an empty or lightly loaded car.

The principal object of the present invention is to provide an arrangement of springs and friction devices in which the degree of friction can be properly adjusted for both empty and loaded cars, and thus to overcome the disadvantages indicated above. To this end the cary truck of this invention is characterized by a friction device which is responsive to a constant pressure, furnishing the desired degree of' friction .for an empty car, and to a further pressure which` is variable, increasing as the ,load on the bolster increases, to augment and intensify the friction between the bolster and side frames and hence to provide the necessary capacity for a loaded car.

Other objects and advantages characterizing our invention, including those derived from simplicity and economy of manufacture, will become more apparent from the detailed description of a practical embodiment of thel invention and a modification thereof which follows hereinafter having reference to the accompanying drawings, whereof:

Fig. 1 represents a top pian view of one end of a bolster and associated parts of va side frame of a railway car truck embodying the invention'with a portion of the bolster cut away to reveal the interior thereof; 4

Figs. 2, 3, and 4 represent vertical cross sections of the same taken as indicated respectively by` the arrows II.-II of Fig. 1, III--III of Figs. 1 and Fig. 5 represents an enlarged vertical cross section of a portion of the bolster taken as indicated by the arrows V-V of Fig. 4;

Fig. 6 represents a side elevation, similarly enlarged, of that portion of the bolster which is formed in a novel manner in accordance with the practice of this invention;

Fig. 7 represents an enlarged view of a friction shoe with a portion thereof shown in side elevation and another portion broken away to reveal the interior construction;

Figs. 8 and 9 represent top plan views ofa modified form of car truck of our invention showing portions of the bolster cutaway to reveal the interior construction and with portions of the side frame shown in section, and with one of the friction shoes removed in Fig. 9; and

Figs. l0 and 11 represent fragmentary vertical cross sections of the modified form of car truck taken as indicated respectively by the arrows X--X and m--XI of Fig. 8.

With-reference to Figs. 1 to '7 of the drawings one form of the invention is illustrated in which the side frame i is of theA usual construction and includes a tension member 2, upon which a spring plank 3 is seated, and vertical columns 4' forming 3 therewith a window within which the` end of a bolster is resiliently supported. In this example the end of the bolster is resiliently supported by main springs comprising four springs 6 and an additional centrally disposed spring 22, all of helical formation and having their lower ends seated on a spring retainer 7. The columns 4 are provided with friction faces 8 engaged by friction shoes 9 carriedin the end of the bolster. It will be observed that all parts of the side frame follow a conventional design and hence only relatively simple and inexpensive changesare required to apply the invention to existing trucks or existing truck designs.

As shown in Figs. l and 2 the end of the bolster 5 is longitudinally divided by a wall Il in the shape of an inverted Y affording inclined surfaces I2 upon which the inner ends of springs I3 are seated. In the interior compartments at opposite sides of the dividing wall II fricton shoes 9 are housed, each such shoe having a side wall I5 in sliding frictional engagement with the friction .faces 8 of the side frame columns l. The top of the bolster 5 is formed with raised offsets I6 extending transversely of the bolster and having a shape to accommodate with vertical clearance raised bosses I'I on the friction shoes 9. The friction shoes 9. are guided and confined to a lateral movement within the interior compartments of the bolster having sliding engagement with the vertical side walls Ill of each compartment and with horizontal surfaces adjacent to the offsets I6 at the underside of the top wall thereof of each compartment. At its bottom wall I8 the bolster is provided with spaced openings I9, see Figs. 4 and 5, through which portions of a yoke 2l pass for communicating the pressure exerted by a spring 22, desirably disposed centrally with the nest of main springs 6i, to the friction shoes 9. Flanges 20 are formed on the sides of the bolster adjacent to the side frame columns 4, see Figs. l and 3. As shown in Fig. 3 the compression member of the side frame is cut away as indicated at 3|)v to provide a space in which the offsets I6 can go when the bolster is at the top of its travel.

Each friction shoe 9 is in the form of a block having a top wall 23 with a horizontal surface in engagement with the underside of the top wall of the bolster 5 at each side of the compartment and having diagonal walls 24 and 25 through which forces are exterted which tend to increase the frictional engagement of the shoes with the side frame. The diagonal surfaces 2d parallel the inclined surfaces I2 of the bolster and serve as seats against which the outer ends of the springs I3 bear. Each spring I3 is disposed at a relatively sharp angle to the direction of the movement of the bolster so that it forces the shoe 9 not only against the friction face 8 of the side frame but also against the top wall of the bolster. By holding the shoe against the: top wall of the bolster, the bolster cannot move downwardly without producing friction between the shoe and the friction face 8 of the side frame. The diagonal surfaces 25 formed at the inner and lower corners of the friction shoes are engaged by spaced wedge members 26 which are urged upwardly by the spring 22 and yoke 2l.

It will be apparent that the springs I3 housed within the friction shoes 9 exert a constant pressure upon such shoes whereas the spring 22 exerts a variable pressure upon both Vshoes of a pair which increases directly with the load on the bolster, and that both springs act independently and in parallel. The constant pressure springs I3 are each confined to movement within a definite space by ribs 21, 31 projecting internally of the friction shoes 9, see Figs. 2 and '1. As shown most clearly in Fig. 5 the yoke 2| has a cap portion 23 which ts over the upper end of the variable pressure spring 22, and has two upstanding'arms 29 which extend through the bolster openings I9 and engage the bottom faces of wedge members 26. As appears in Fig. 4 each wedge member 2B passes through an opening 3| in the central wall II of the bolster 5 and hence bridges between the separate compartments formed in the bolster and equalizes the pressure exerted by spring 22 tending to spread the friction shoes 9. Diagonal faces 32 on the wedge members 2B engage the surfaces 25 of the friction shoes and transmit the force of spring 22 to such shoes, and also transmit the load on the bolster to spring 22.

Desirably the constant pressure springs I3 are designed to produce a force, tending to move the friction shoes outwardly, sufllciently dampening the main springs to insure good riding qualities for an empty or lightly loaded car; whereas the variable pressure spring 22 is -designed to produce an independent force acting in the same direction and. suilciently dampening the main springs to insure good riding qualities for a loaded car.

frame Ia is in all respects similar to the side frame previously described except that the compression member need not be cut away in the manner illustrated at 30 in Fig. 3, but may take the usual conventional form. The tension member is indicated at 2a and the vertical columns at 4a. The spring plank 3a and spring retainer 'Ia are also unchanged, and the columns 4a are provided with friction faces 8a engaged by friction shoes 9a in the same manner as in the construction previously described.

In this example, however, the bolster 5a is resiliently supported by main springs of helical formation which comprise four double springs 6a engaging the underside of the bolster and a double spring 22a disposed centrally of the group and engaging a. yoke 2Ia.

The end of the bolster 5a is formed somewhat differently from the bolster as previously described but is similar thereto in the respect that it is transversely divided by Walls Illa and longitudinally divided by a wall I Ia in the shape of an inverted Y affording inclined surfaces |20, upon which the inner ends of springs I3a are seated. In the interior compartments defined at opposite sides of the bolster by walls Illa and wall Ila are housedshoes 3a which have top walls 23a with slightly cambered surfaces in sliding engagements with the underside of the top wall of the bolster 5a. Each shoe 8a has a side wall I5a in sliding frictional engagement with the friction faces 8a of the side frame columns 4'a. At its bottom wall the bolster 5a is provided with openings IQa, through which the upstanding arms 29a of yoke 2Ia pass for communicating the pressure exerted by the double spring 22a to the friction shoes 9a through a diagonal surface of a wall 25a at the center thereof. Yoke 2 Ia is formed in one piece and has inclined wedge surfaces 26a engaging the friction shoes 3a.

In the recesses at either side of the central wall 25a of each friction shoe 9a springs I3a are housed, there being two such springs associated with each friction shoe. The springs I3a exert In Figs. 8 to 1l a modified form of car truck of .this invention is illustrated in which the y side '5 a constant pressure upon the friction shoes whereas the double spring 22aacting through the yoke 2Ia exerts a variablepressure upon the shoes increasing directly with the load'ori the y subdivision of the bolster to accommodate such elements, all without departing from the spirit of the invention as defined in the annexed claims.

Having thus described our invention, we claim:

1. In a car truck, a side frame, a bolster 'resiliently supported on said side frame, a shoe carried in the bolster and frictionally engaging a surface of the side frame, spring means urging said friction shoe .against said surface comprising a spring maintaining a constant force on the friction shoe regardless of the weight on the bolster, and a spring maintaining a variable force on the friction shoe increasing directly with the load on the bolster, the total force between the friction shoe and said surface of thel side frame being at alltimes the sum of the independent` forces exerted separately'by the constant force spring and the variable force spring.

2. In a car` truck, a side frame, a bolster resiliently supported in said side frame, a shoe carried on the bolster and having capacity for lateral movement with respect to it and adapted to frictionally engage a surface on a column of the side frame, and spring means urging said friction shoe outwardly against said surface comprising a spring within the bolster maintaining a constant force on the friction shoe regardless of the weight on the bolster, and a spring beneath the bolster, acting through an element within the buster for maintaining a variable force on the friction shoe increasing directly with the load on the bolster, said latter spring acting in parallel with the rst mentioned spring,

the total force between the friction shoe and said surface of the side frame being at all times the sum of the independent forces exerted separately by the constant force spring and the variable force spring.

3. lA car truck as described in claim 2 in which the friction shoe is in the form of a block having one bearing surface paralleling the plane of the bolster and in sliding engagement therewith and another bearing surface paralleling the column of the side frame and at right angles to said rst bearing surface.

4. In a car truck, a side frame, a. bolster resiliently supported on a tension member of said side frame, a shoe carried in the bolster and having capacity for lateral movement and adapt-4 ed to frictionally engage a surface on a column of the side frame, and spring means urgingsaid friction shoe outwardly against said surface comprising a constant. pressure spring having` one end bearing against a part of the bolster and the other end bearing against said-friction shoe,

e the constant pressure spring is housed within the friction shoe withits ends bearingv upon inclined surfaces of theA bolster and friction shoe.y

7. A car truck as described in claim 4 in which the constant pressure spring is housed within the friction shoe and the variable pressure spring exerts its force through walls of the shoe between which theconstant pressure spring is housed.

8. A car truck as described in yclaim 4 in which the constant pressure spring is housed within the n friction shoe, and the wedge means include spaced elements engaging walls of the friction shoe be-4 tween which `saidspring ishoused, and said variable pressure spring exerts its force through a yoke engaging lsaid spaced elements.

9. In a car truck, a side frame, a bolster 'esiliently supported on a tension member of said side frame with the portion thus supported divided longitudinally of the bolster into interior compartments, friction shoes carried in such compartments and having capacity for lateral 'movement thereinuand having outer surfaces frictionally engaging surfaces on the columns of the side frame, constant pressure springs in such compartments urging said friction shoesoutwardly toward said columns, and a variable pressure spring disposed between the bolster and said tension member, and wedge means disposed between said variable pressure spring and the friction shoes and-tending to. spread said shoes under the influence of said variable pressure spring with increasing force as the load on the bolster increases.' A

' 10. A car ltruck as described in claim 9 in which the wedge means include an element bridging between said compartments in vthe bolster and acting uponfriction shoes disposed at both sides of the division of the bolster.

11. A car truck as described in claim 9 in which the friction shoes are` paired,' one shoe of a pair being at each side of the division of the bolster, and the wedge means equalize the pressure exerted by the variable pressure spring tending to spread the shoes of a pair.

.12. A car truck as described in claim 9 in which the bolster isdivided by a 4wall in the shape of an inverted Y' 'affording inclined surfaces upon which the inner ends of the constant pressure springs are seated.

'13. A car truckas described in claim 9 in which the wedge means include a one-piece yoke bear- Y ing upon the variable pressure spring and havthe side frame, and spring means urging said a variable pressure spring disposed between the bolster and said tension member, 'and wedge means disposed between said latter'spring Aand the friction shoe.

5. A car truck as described in claim 4 in which the constant pressure spring is housed within the friction shoe and inclined at an angle to exert a force in the same direction as said wedge means.

6. A car truck as described in claim 4 in which friction shoe outwardly against said surface cornprising a spring maintaining a constant force on the friction shoev regardless of the weight on the bolster, and a spring maintaining a variable `force on the friction shoe increasing directly with the load on the bolster, said latter spring acting in parallel with the first mentioned spring; and said friction shoe being in the form of a block having a horizontal surface in sliding engagement with the bolster, a vertical surface in sliding engagement with the column of the side frame, and diagonal surfaces through which the aforementioned springs exert their forces.

audace the bolster, and a spring for maintaining a vari- 1 able force on the friction shoe increasing directly with the load on the bolster, said latter spring acting in parallel with the first mentioned spring. and said friction shoe being in the form of a block havingV a top wall in sliding engagement with the underside of the top wall of the bolster. a side wall in sliding engagement with the column of the side frame, and diagonalwalls through which the aforementioned springs exert their forces independently but in the same direction. l

CHARLES D. BARREIT. CHARLES R. WHITEHEAD.

REFERENCES cri-nn The following references are of record in the me of this patent:

UNITED STATES PATENTS Number A Name Date 1,243,007 Taylor Oct. 18. 1917 15 2,053,989 Goodwin Sept. 8, 1936 2,141,767 Camp Dec. 27. 1938

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