US1764720A - Railway-car-truck spring - Google Patents

Description

June"17,1930. C.HANK1NS' RAILWAY GAR muck sPiu'Nc Filed Jung 13, 1925 1 ZSheetS- Sh eet l June17, 1930. c. HANKINS RAILWAY CAR TRUCK SPRING 2 Sheets-Sheet 2 Filed June 13, 1925 ILA [Ill

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aorasn'wat V a .Aoa red car wmwwwwuwm awe/14 601 Patented June 17, 1930 UNITED srArs rarer mes CYRUS HANKINS, or BALTIMORE, MARYLAND, AssIeNoR, BY ivinsnnnssienmnurs TO T. H. SYMINGTON' AND son, Inc, on BALTIMORE, MARYLAND, A oosronA'rIon OF MARYLAND RAiLwAY-oAR-rnncK srnme Application filed June 13, .1925. Serial No. 36,978.

, The invention relates to: springs for use in railway car trucks.

The principal object of the invention, generally stated, is to provide cushioning means having, a varying rate of deflection for in creasing loads.

The object of the invention, more speciflcally stated, is to provide a spring device enibodying sets of spring cushioning members having varying rates of deflection under load, the arrangement being such that the spring will have a capacity curve with an acceleratedly increasing capacity per unit rate of deflection, there being a lesser change in capacity for a unit deflection within the range of an unloaded car than within the range of a loaded car. i

.zrnother object of the invention is the provision of a spring device for railway car trucks, in which use is made of a plurality of sets of concentric leaf or plate springs, each set including groups of plate springs certain of which have their centers at opposite sides of a plane between successive groups, certain rates wherebyto obtain the desired result.

A further object of the invention is to pro vide a spring device for railway car trucks having an increased capacity beyond the point of deflection for a normally loaded car.

To the. attainment of the foregoing and other objects which will hereinafter appear, the invention preferably consists in the combination and arrangement of parts to be hereinafter more fully described and claimed and illustrated in the accompanying drawings in which: i

Figure 1 is a side elevation of a truck having the spring structure or device installed therein,

Figure 2 is a substantially central vertical cross section showing the relation of the springs under a light load,

Figure 3 is a similar view showing the relation under a heavy load.

Figure i is a detail longitudinal section,

Figure 5 is a perspective view showing the banks or groups of springs removed and separated for the sake of clearness of the groups having different deflection.

Figure 6 is a view showing thecapacity: curve, under compression and also. release.

Referring more particularly to the drawings wherein like reference characters designate corresponding parts. throughontthe sev- 5' eral views, the numeral. 1 designates, generally, a. truck having the usual side frame 2 formed to provide a window opening 3 for the reception of the spring device which is located beneath and which supports the bol-* ster t. While a certain type oftrnlck side frame is disclosed it should be ini derstood. that there is no limitation in this respect as. it is for illustrative purposes only. i

In my co-pending applications, Serial Nos. 36,975, 36,976, 36,977, all filed. June 13th, 1925, and Serial No. 38,547,iiledJune 20th, 1925, I have disclosedthe mechanical details of construction of the spriugdevice located within the window 3., which springdevice is indicated generally by the numeral 5. For all purposes of the present application it is sufficient to state that the spring device includes upper and lower pan inenibersor cas ing sections 6 and 7 respectively, which arear- 7 ranged with their open sides toward each other with the cushioning means ofthe pres-- ent. invention interposed between them, and I which are of a size and shape to fit Within" the Window opening 3 between the spring seat and the bolsten. In said coepending applications I have disclosed means for maintaining the pans in position within the Win dow opening and meansfor maintaining them initially in a certain position with respect to each other with the cushioning means under initial compression, 1 andv though the same mechanical features may be adopted in the present instance it is believedf that a repetition of the illustrative and de- 0;,

scriptive matter is unnecessary;

The present invention resides in the enlployment of sets of cushion devices each of which preferably. consists of a. plurality of elongatedplate or leaf springs located with-i in and between the pan members 6 and 7 and arranged in such manner thatthe different; sets or groups will have different rates of'def 'liection depending upon the load. While va;

'riations may be resorted to I have, for com we venience, shown the use of three sets of springs, the sets being designated generally by the numerals 8, 9 and 10, the first and last named being represented as identical.

The sets 8 and 10 each include banks or groups 11 and 12 of elongated leaf or plate members longitudinally curved, the plates forming each group being arranged in contacting and conforming relation and those in the group 12 being arranged upon the group 11 and with the curvature opposite. It will consequently be seen that the central portions of the uppermost plate or leaf in the group 11 and the lowermost plate or leaf in the group 12 will be in contact. Superpos'ed upon the group 12 are the preliminary springs and while various arrangements might be adopted I have shown this means as including oppositely curved leaves or plates 13 and 14 disposed with their convex sides in contact, the concave side of the spring 14 being toward the concave top of the group 12.

The set 9 constitutes the light car springs and this set may include groups 15, 16, 17 and 18 which may have the same .or a different number of leaves therein, as may be preferred. The groups 15 and 16 are arranged with their convex sides together, as are the groups 17 and 18, but the group 17 has its concave side disposed toward the concave side 'or top of the group 16, the points of contact being at the ends. In all sets it may be said that the centers of the springs in contacting groups are located at opposite sides of the plane between the groups. 1

The sets of springs are of course confined between the pan members 6 and 7 and are preferably placed under initial compression. Initially, the preliminary springs 13 and 14 of'the groups 8 and 10 hold the main springs 11 and 12 thereof in position. A possible contra-flexure of the uppermost springs of all the sets resulting from inequalities in the leaves or plates may be prevented by the use of a.transverse center bearing element 19 located within the upper pan 6 though this is a detail which is likewise illustrated in one of the above mentioned co-pending applications. 7

Initially the preliminary springs 13 and 14 are of course flexed to a certain extent and in Figure 2 the substantially free position or initialposition thereof is illustrated. Under light load conditions the preliminary springs 13 and 14 will of course be deflected at a very rapid rate while the intermediate springs 15, 16, 17 and 18 are also deflected, though to a less extent. Obviously all the springs in all the groups are deflected to a certain extent but the main springs 11 and 12 will naturally be deflected to a much less extent than any of the others. As the load increases the main springs 11 and 12 will be deflected to a greater extent but owing to the peculiar arrangement of the various sets and the various groups or banks in each set it will be clear that the actual deflection under increasing loads will progress at a decreasing rate. This may best be understood by referring to Figure 6 which shows the capacity curve. In this figure it will be seen that a slight increase in the load, under light conditions, will result in a considerable actual travel of the springs under the compressive strain, the rate of deflection, however, decreasing as the load is increased. From the approximate loaded car condition it will be seen that the actual movement of the springs or the rate of deflection under materially increasing loads is much less. In other words, it may be said that the springs will have an acceleratedly increasing capacity for a constant rate of deflection.

From a study ofFigure 6 it will be observed that by utilizing plate springs arranged in accordance with the invention that I obtain as hereinbefore set forth an accelerated increasing capacity for each added equal increment of travel and that I also obtain a release curve in which the major portion of the recoil in terms of load takes place within approximately the first half inch of travel and that the amount of load on the spring for the last portion of its recoil movement is comparatively slight. The area between the compression curve and the release curve is the amount of load which is dissipated by the frictional resistance between the various sets of spring plates and since this release curve follows very closely the compression curve the final return of the springs to normal position will be comparatively as slow if not slower than the reaction of the springs to load. ,This action of the springs on release will serve to relieve the car parts and lading of excessive jolts and jars and hence will result in increased life of the car parts and less damage to the lading than does result from the use of coil springs.

By utilizing plate springs arranged in accordance with the invention the same characteristic curve is produced from either light or loaded position when the car is subjected to rocking or shocks which are less in intensity than the maximum capacity of the springs, that is assuming for instance the parts to be in the normal loaded position and a shock transmitted to the springs either by a low spot in the rail or by the oscillation of the cars the load line will follow the nor- 1 mal compression line to a point where the capacity of the springs is equal to the load imposed. The release curve from this point will drop downwardly until it becomes tangent to the release curve of the springs when subjected to maximum loads and as soon as re-application of load occurs the compression line will mount from this point and become tangent to the true compression curve of the entire set of springs. This same action takes place under light load conditions as well as under full load position of the springs. The area subtended between the compression line and the release line of each of these supplemental compression and release curves represents graphically the amount of energy dissipated by the frictional resistance of'the spring.

From the foregoing description and a study of the drawings it will be seen that I have thus provided a simply constructed and arranged spring device which will possess the advantages above pointed out and which will consequently be eiiicient in action and durable in service.

lVhile the preliminary springs are shown as consisting of plates superposed upon the groups which form the main springs it is obvious that alternative arrangements are possible inasmuch as the location may be reversed or otherwise changed. Furthermore it is evident that the light car springs constituting the central group in the present disclosure might be duplicated and arranged outwardly of whatever springs are provided as the main and preliminary ones. In addition to such changes it is clear that the number of leaves in certain groups may be equal or unequal as preferred inasmuch as all such suggested modifications would not affect the principle involved nor the action of the complete unit under light or heavy load conditions. Vhile certain alternative arrange ments have been suggested above it should be understood that the right is reserved to make all such further modifications as will not depart from the spirit of the invention or the scope of the claims hereunto appended.

Having thus described the invention, I claim:

1. In a spring for railway trucks, a plurality of curved plates arranged in a plurality of successively contacting banks, the curved plates in one or more banks being arranged in a varying number from the other banks, and the whole having a varying rate of deflection proportional to the loads imposed thereon. r

2. In a spring for railway trucks, an ar rangement of curved leaf springs of equal length having lesser numbers of leaves active for light loads and greater numbers of leaves active for greater loads.

3. A railway truck spring comprising a plurality of spring leaves of equal length having a capacity curve with an acceleratedly increasing capacity for a constant rate of defiection.

4. A spring for railway trucks comprising a plurality of leaves of equal length having a lesser change in capacity for a unit deflection within the range of an unloaded car than within the range of the loaded car.

5. In a spring structure for railway trucks, groups of varying numbers of curved plates of equal length arranged to give a decreasing rate of deflection under increasing loads.

6. Curved plate springs of equal length for railway trucks having a variable rate of deflection for diiierent conditions of car loading and an increased capacity beyond the point of deflection for a normally loaded car.

7. Plate springs for railway trucks arranged in a plurality of contacting banks of equal length having dil'lerent deflection rates.

8. Plate springs for railway trucks arranged in a plurality of banks, one or more banks being arranged to go solid before the remaining hanks go solid.

9. In a curved plate spring structure for railway trucks, a plurality of banks of curved plates retained under initial compression, and means for distributing the load of subsequent compression to all the banks.

10. In a plate spring for railway trucks, a plurality of banks, one or more of said banks including two or more groups of plates having difi'e'rent rates of deflection, and means for transmitting the load on the groups having the greater rate of deflection through the same onto the groups having the lesser rate of deflection.

11. In a spring structure for railway trucks, groups of varying numbers of curved plates arranged to give a decreasing rate of deflection under increased loads, said springs also being adapted to give a progressively increasing rate of deflection upon release.

12. In a spring structure for railway car trucks, retaining members and a plurality of sets of elongated curved plate springs located between and in engagement with the retaining members and arranged side by side, each set comprising a plurality of groups alternate ones of which are oppositely curved.

13. In a spring structure for railway car trucks, retaining members and a plurality of sets of elongated curved plate springs located between and in engagement with the retaining members and arranged side by side, each set comprising a plurality of groups alternate ones of which are oppositely curved, the number of plates in certain groups being greatly in excess of those in other groups.

1 1. In a spring structure for railway car trucks, retaining members and a plurality of sets of elongated curved plate springs locat ed between and in engagement with the re taining members and arranged side by side, each set comprising a plurality of groups alternate ones of which are oppositely curved,

the corresponding groups in the diiferent sets 7 containing a different number of plates.

15. In a spring structure'for railway car trucks, retaining members and a plurality of sets of elongated curved plate springs lo-' cated between and in engagement with the retaining members and arranged side by side,

each set comprising a plurality of groups alternate ones of which are oppositely curved the corresponding groups in successive sets containing different numbers of plate springs and the corresponding groups in alternate sets containing the same number of spring plates.

In testimony whereof I afiix my signature.

CYRUS HANKINS.

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