US1641719A - Car-truck spring - Google Patents

Description

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Patented Sena e, raar.

TATES JOHiIr C. WHITBIDGE, OF COLUMBUS, 01H10, ASSIGNOR 'lO` THE BUCKEYE STEEL CAST- NGS COMPANY, OF COLUMBUS, OHM),

CAR-TRUCK SPRING.

application mea october as, 192e. serial no. maare.

rIhis invention relates to means for ab- :orbing shocks in car trucks and preventing excessive swaying when the car is operated over uneven track.

Railway cars are carried on trucks whichy are always provided with means for yabsorbing the energy of blows or vertical movements due to imperfect track conditions. The imperfections which cause the most serious disturbance are those of vertical alinement, ,such as defective or yielding rai'l joints, and gaps at frogs and crossings, by ,reason of which the wheels of a car are continually being dropped more or less abruptly through small distances, the entire weight of the car being also dropped. This 'condition imparts energy to all parts of the car, -the more yielding parts absorbing the energy with the least destructive effect. The means most commonly employed to absorb the energy of the vertical blows or movements is a group of helical springs disposed between the spring plank and the bolster, which springs absorb energy at a uniform rate up to the point vwhere the spring coils are all closed ,or the spring comessolid, It often happens that the capacity of the springs is not suiiicient to absorb'all theenergy of a given blow, in which event the ener i unabsorbed when'the spring is solid is ta en up by other yielding parts of the car and trucks. l l

A part of the energy Jabsorbed by thecompression of the springs is expended by them 1n resuming the normal static load height, and this action causes a swaying or oscillation of thecar which is cumulative if the interval between blows is synchronous with the period of oscillation of the s ring. The

accumulated swaying vtends to ecome destructive of the car and causes the wheel 'loads on the rails to fluctuate, alternately,A

on the two sides ofthe truck, the minimum wheel load sometimes becoming small enough to permit the advancing wheel on the outside of a curved track to climb the rail and derail the truck.'y

The objects of the present invention are to increase the spring capacity of the truck, to introduce a frictional element to more effectively absorb the energy of blows, and to introduce an element which will' effectively interfere with the cumulative 'swa ng of the car. These objects are attained 1n such an arrangement as is,illustrated in the accom- 1 panying drawing, and the invention vresides isernia garant carica,

in certain novel features which will be hereinafter first fully described and then more particularly pointed out in the Yappended. claims. f

In the drawing, Figure 1 is a view, partly in side elevation and partly in vertical section, of a portion of a car truck embodying the invention;

Figure 2 is a horizontal section on the line 2-2 of Fig. 1, the line 1-1 in Figure 2 indicating the p'lane of the section shown in Figure 1;

Figures 3 and 4 are diagrams.

In the drawing, the reference numeral 1 indicates a side frame; 2 a sprin lank', 3v a bolster, and 4 helical springs ofgthe usual form resting on the spring plank and supporting the bolster, the ends of the spring ,plank and the bolster being disposed in an opening provided therefor in the side frame.

In the illustrated embodiment of the present invention, the bolster is provided with an opening 5 through its bottom and with a recess or seat 6 in its .floor around.I said opening. On the sides of thefbolster, at the topk thereof, are inwardly projecting overhanging lugs or-stops 7 and on the inner surfaces of the bolster sides are vertically disposed l guidin and retaining ribs 8. Fitted throug the opening 5 is a plunger 9.having an overhanging headlO, a seat 11 resting on the head with its ends disposed between the ribs Le mbe guided thereby, and a leaf spring 12 resting at its center on the seatl with its upwardly bowed ends engaging i under the stop lugs 7. After the parts are brought into the proper approximate relation, the plunger is raised slightly and a keeper washer 13 is engaged under the head 10 and within the recess 6 thereby retaining the initial compression of the spring 12 and 'i holding the lower end of the plunger 0E the spring plank, it4 being intended that the .y clearance at 14 beless than the travel rof V the helical springs but greater than the heliwill compress the 'spring 12, thereby bringing additional` spring capacity into action and also dampenlng and avoiding the serious accumulation of swaying.

Referring to Figure 3, th

s j degree pf helical spring loading is represented `by ver y swayin l of the two ty es of springs.

tical distances between the lines O C and O D, the springs absorbing) energy at a uniform rate, as represented y the straight line O D until thel springs come solid, the load or force on the springs being then represented by the line A E,-the same force bein transmitted to the sideframe and the bo ster spring seat. When the whole energy of the blow is absorbed by the helical springs, that ener will be represented by the area FGAE, ut it frequenly happens that the energy of the blow is in excess of the stated area and must be absorbed by other partsaof the truck and car. This over solid 7force on the springs may be represented by the line B C and its magnitude depends on the stiffness of the varlous ,members of the truck receiving the spring load. It will, of course, be understoodthat the helical spring diagram terminates at the line A E. y l

` In Figure 4, the line R S corres onds to the line O D in Fig. 3. lThe point on the line RIS' represents the oint where the plunger be 'ns to actuate t espring 12, and the curve W V represents the performance of the helical and leaf springs combined while bein compressed under the oscillating load. he curve V X T shows the performance of the combined springs under release of load, the area between the curves T W V and vV X T being a measure of the energy absorbed in overcoming the frictionr between the leaves of the spring 12.

Comparison of .the diagrams shows that the invention provides increased spring capacity without increasing the total spring travel and provides this increase in capacity at the point where it ismost effective. -Furthermore, the energy imparted to the spring combination is in part taken up by friction and is thus prevented from returning to the spring and setting up cumulative 1n the car. The eriods of oscillation othe leaf and he ical sprin are obviously different and this fact urther i tends to stop the cumulative swaying by rea-v son of the mterference between .the periods Having fu y described my invention what I claim asnew and desire` to secure by Let- 1. A car truck including a spring plank,

a bolster, helical s ringson the spring plank supporting the bo ter a plunger supported y byI and extending downwardly through the bottom of the bolster and movable upwardly therein and having its lower end normally free of the spring plank, a seat on the upper end of the plunger, and a frictional spring resting on'said seat and having'its upwardly bowed ends engaged with the top of thev bolster. y

2. A clar truck includinga spring plank, a bolster, helical springs on the spring plan supporting the bolster, the bolster having an opening through its bottom and being provided on its sides with spaced inwardly projecting ribs and with inwardly projecting lugs between the ribs, a plunger extending through the opening in the bottom of the bolster and having an operhan ing head at its upper end, the lower end of t e plunger being normally spaced vertically from the spring plank, a follower -resting on the head of the plunger and having its ends disposed between ribs on the sides of the bolster, and a leaf spring resting at its center on the follower and having its ends upturned and engaged under the lugs on the bolster.

3. A car t-ruck equipped with helical springs of a set load capacity, a hollow bolster resting on said springs and yhaving spaced verical ribs on Jthe inner surfaces of its sides, a friction leaf spring arrange horizontally Within the bolsterwith its ends between the respectively adjacent ribs, and

means for maintainingthe frictional spring inactive under normal load and activating it upqn delivery of a'load in excess of said normal load. 4. A car truck including abolster having vertical ribs on its inner side walls, helical springs-supporting the bolster under normal load, a frictional leaf spring arranged horizontally between the vertical ribs on vthe bolster, and means for activating the leaf l springv sequentially with the r'helical spring. 5. car truck including a spring plank, a hollow bolster, helical springs carried by the spring plank and supporting the bolster,

a friction spring arranged horizontally within the bolster and having its ends enigaged with the top thereof, and a plunger mounted'in and depending from the bolster and supporting the friction spring, 'the In testimony whereof, I have signed this specification. y

JOHN c. `Wniframes.

lower end of the plunger being normallyl e spaced vertically -from the spring plank.

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