US2097418A

US2097418A - Spring

Info

Publication number: US2097418A
Application number: US23570A
Authority: US
Inventors: Alfred H Oelkers
Original assignee: American Steel Foundries
Current assignee: American Steel Foundries
Priority date: 1935-05-27
Filing date: 1935-05-27
Publication date: 1937-10-26
Anticipated expiration: 1954-10-26

Description

Oct. 26, 1937. A. H. OELKERS SPRING Filed May 27, 1935 4 Sheets Sheet l Oct. 26, 1937. A. OELKERS SPRING Filed May 27, 1935 4 Sheets-Sheet 2 Oct. 26, 1937.

A. H. QELKERS SPRING Filed May 27, 1935 4 Sheets-Sheet 3 Patented Oct. 26, 1937 UNITED STATES PATENT OFFICE SPRING Alfred H. Oelkers, Chicago, Ill.,' assignor to American Steel Foundries, Chicago, 111., a corporation of New Jersey Application May 27, 1935, Serial No. 23,570

19 Claims.

This invention relates to spring assemblies, and more particularly to car trucks including such assemblies, this application being a continuationin-part of copending applications Serial Nos. 470,318 and 593,954, filed July 24th, 1930,'and February 19th, 1932, respectively.

Among the objects of the present invention is to provide a spring assembly including a leaf spring for supporting a load and means for increasing the energy absorption thereof when under load.

Springs as generally used in vehicles are for the purpose of cushioning the shock when the wheels of the vehicle pass through or over irregularities of the roadway. This spring cushioning means is usually interposed between the wheel and axle assembly and the vehicle body, thereby protecting the body and its contents from road shocks. Two kinds of mechanical springs made of steel are commonly used, namely, coil springs, consisting of helically wound steel bars and el1iptic, semi-elliptic, or plate springs consisting of a pile of comparatively thin plates used as a flexible beam. Insofar as providing resiliency, the coil spring is the more eflicient of the two; ac-f cording to the usual standards of design less than one-half the weight of steel is'required in a coil spring than would be needed in a plate spring of equal capacity. p

The coil spring releaseswith practically the same force and energy as that required to compress it, there being practically no energy absorbed in the compression-release cycle. A leaf spring, as usually constructed from a number 8.3 of plates forming a beam, returns considerably less energy when released than is required to compress or deflect it. This diiference of energy be tween the compression and release action is due to the friction between the adjacent plates, both during the compression and release stroke. In a leaf spring of the type usually used on railway cars, this energy absorption in a complete compression and release cycle amounts to from 20 to 30 percent. 43 Experience with railroad equipment has proven that when a car is carried on coil springs alone, conditions often arise under higher speeds where impulses from track irregularities harmonize with the natural up and down movement of the car body that cause excessive and damaging vertical oscillations to the car and. its lading. When car bodies are carried on leaf springs this condition is prevented because of the energy absorbed in each movement of the spring, both on compression and release. Carrying of the car body entirely on leaf springs is, however, objectionable because it adds much weight to the truck construction, and even though leaf springs weighing three times as much as coil springs are used to do the same work, the former have a shorter life. The spring arrangement made in accordance with the present invention makes use of the more economical coil spring for carrying the major portion of the weight and .atthe same time employs a leaf spring to carry a smaller portion of the weight, the latter, however, providing practically the same frictional absorptionbetween the plates as though the entire weight was carried on leaf springs.

It is therefore an object of the present invention to provide a spring assembly consisting broadly of coil and leaf springs which, in combination, have practically the same frictional absorption as .a complete leaf spring of the same capacity. Y

Another object is to provide a spring assembly in which the major portion of the spring resiliency V is obtained through deflection of coil springs} while all of the weight carried on'the' spring assembly is utilized to cause friction between the plates. of a semi-elliptic or leaf spring of the combination.

A further object is to provide helical or coil springs in an assembly with leaf springs so that the coil spring provides the desired weight carrying resiliency and the leaf spring the desired frictional absorption. v f Still another object is to provide a combined spring assembly in which all of the weight carried thereby is supported by the top plate of the leaf spring and is transmitted to each of the lower leaves so that the pressure between any two adjacent leaves is equal to the weight on the spring assembly, but in which combination only a portion of the weight carried is suspended by the leaf spring as a beam, the other portion of the weight being carried directly by the coil springs.

Yet another object of the present invention is toprovide a novel spring assembly in a railway truck in which a minor portion of the weight carried is utilized to flex the leaf spring, a major portion of the weight flexes the coil springsand all of the weightis utilized to cause frictional absorption between the plates of the leaf spring. Still a further object of the invention is to provide a spring group in a railway truck form- 7 ing a; resilient means for carrying the bolster or other load carrying member in relation to the side frame without any metallic contact between the two. This is accomplished by the leaf spring in that it has a band rigidly secured in the center portion of the leaves, with which the bolster or other load carrying member may make contact to prevent its shifting longitudinally with the truck side frames. Furthermore, the bolster or other load carrying member is prevented from shifting crosswise in relation to the side frame by contact against the sides of the leaf springs.

The present invention also contemplates the idea of providing a spring suspension between the truck bolster or other load carrying member and the side frame which prevents wear between these two members because it eliminates contact between the two. 7

Another object within the purview of the present invention is to provide a spring assembly between the side frame and bolster or other load carrying member of a railway truck which holds the bolster or other load carrying member nominally level, prevents its shifting endwise in relation to the'side frame and prevents its lateral displacement in relation to the side frame, all without direct contact between the bolster or other load carrying member and the side frame.

Still another object is to provide a plate spring for such an assembly in which the band is secured against endwise shifting on the leaf spring.

A still further object is to provide a leaf spring for such an assembly in which the weight carried on the top leaf of the spring is distributed over at least two distinct areas.

The invention further contemplates the idea of providing a leaf spring for such an assembly which has a band in the middle portion secured against endwise shifting and at the same time readily assembled so that any one or more plates are easily replaceable.

Other objects, features, capabilities and advantages are comprehended by the invention, as will later appear and as are inherently possessed thereby.

Referring to the drawings:

Figure 1 is a view in side elevation partly in section of a truck side frame incorporating a spring assembly made in accordance with the present invention;

Figure 2 is a View in elevation partly in section of a truck side frame incorporating another spring assembly made in accordance with the present invention;

Figures 3 and 4 are views in side elevation of truck side frames embodying modified forms of the invention; and 7 Figures 5 to 28 inclusive show detailed views of various means for securing the leaves of leaf springs together.

Referring now more in detail to the drawings, a spring assembly made in accordance with the present invention is shown in a truck side frame 2 which comprises a rigid member substantially U-shaped in side elevation, this member being provided with the elongated central portion 4 of substantial box-section provided with upwardly extending end portions 6 terminating in axle journal cooperating portions which, in the embodiment illustrated, are the journal boxes 8. This box girder formation of the side frame gives great strength, rigidity and simplicity of construction and design. The journal boxes are provided with the usual brasses and wedges to cooperate with journal ends of wheel and axle assemblies (not disclosed), it being understood, of course, that any formation of wheel and axle assembly may be used, in which case the journal boxes may be modified accordingly.

The side frame portions 6 adjacent the journal boxes are provided with the spring seats l0 adapted to receive the ends of the leaf spring assembly l2, the seats Ill preferably being arouate or convexed upwardly whereby deflection of the leaf spring will shorten the effective length of the springs. That is, the seats for the elliptic springs are so arranged that when a light load is applied to the springs, the distance between the supporting points 'of the spring will be greater than when a heavy load is applied. It may therefore be said that a convexedly shaped seat of a leaf spring automatically shortens the span, and the load carrying capacity of the leaf spring is increased as the weight to be supported is increased.

A load carrying member, such as bolster M or the like, which maybe provided with center and side bearings, is supported by the side frames on the leaf springs as at [6 and i8 and may be provided, if desired, with spaced arms (not disclosed) adapted to cooperate with the leaf spring bands 20 whereby the same is held in position. Interposed between the rigid member and the leaf spring assembly are coil spring assemblies 22 and 2-3 which load the leaf spring assembly l2 to thereby increase the amount of energy the leaf spring will absorb. With this arrangement, the load from the bolster M is transferred to the upper leaf spring areas to compress the surface of the plates together, thus producing increased frictional absorption within the plate springs.

In the form of construction shown in Figure 1 of the drawings, it has been found that although very satisfactory, nevertheless the maximum percentage of frictional absorption within the spring assembly l2 has not been obtained by mounting of the bolster, or other load carrying member I4, as at l6 and I8. To provide for a greater percentage of frictional absorption within the spring assembly, the same may include novel supporting loading blocks for load carrying members, such as a bolster or the like. As illustrated in Figure 2 of the drawings, the spring assembly may be incorporated in a truck side frame 2 corresponding to the side frame shown in Figure 1 of the draw ings, having the elongated central portion 4 with upwardly extending end portions 6 terminating in axle journal cooperating portions which, as shown, are the journal boxes 8, these journal boxes also being provided with the usual brasses and wedges cooperating with the journal ends of wheel and axle assemblies (not disclosed). As in Figure 1 of the drawings, the side frame portions 6 adjacent the journal boxes are provided with the spring seats I 0 which are arcuate or convexed upwardly and are adapted to receive the ends of the leaf spring assembly 26 which, in the present embodiment, contains a greater number of leaves than the leaf spring assembly I2.

In the present embodiment, a load carrying member such as a bolster 28 or the like, spans between the side frames of the truck and has its ends mounted on the leaf spring assemblies 26. The bolster 28 cooperates adjacent each end with the loading blocks 30 and 32 disposed therebetween and the leaf spring assembly 26, these loading blocks being crowned as shown and cooperating at spaced points with the bolster to provide a support therefor. These crowned loading blocks are supported upon the top leaf of the leaf spring assembly 25 at spaced

points

34 and 36, and 38 and 66, respectively, whereby the load from the load carrying member 28 is applied to the leaf spring assembly at four distinct points,

points 34 and 36 being disposed on one side of the center line of the leaf spring assembly, and points 38 and 40 being disposed on the other side of the center line of the leaf spring assembly. The leaves of the leaf spring assembly 26 in the present embodiment are positioned by means of the spring band 42, and the bolster or other load carrying member may be provided with parts embracing the leaf spring assembly which maycooperate with the spring band 42 whereby the same is operatively positioned. Interposed between the elongated central portion 4 of the side frame and the underside of the leaf spring assembly 26 are coil spring assemblies 22 and 24 which load the leaf spring assembly tothereby increase the amount of energy this leaf 'springwill absorb.

It has been found that where a load from the load carrying member is transmitted to the leaf spring assembly at a plurality of distinct points, as shown in Figure 2 of the drawings, a maximum percentage of frictional absorption within the leaf spring is obtained. Such construction is desirable for trucks used in refrigerator cars, cabooses, express or baggage cars.

If desired, the leaf spring assembly I2 or 26 of Figures 1 and 2 respectively, may be constructed as shown in Figures 3 and 4. In these figures, means are shown for locking the band on the leaf spring. In each of the constructions, the side frame 44 is similar to the side frame 2 being provided with the journal boxes 46, the spring pocket 48 formed adjacent the journal boxes being provided with the recessed portion 50 for the reception of the wearing pad 52 disposed in said recess, the end wall 54 of said pocket being adjacent the journal box and terminating upwardly either in spaced lugs, or a wall connecting the spaced pocket forming flanges 56. The ends of the lower leaf are provided with the arcuate bearing portions 58 engaging the wearing pads 52.

In each of the spring constructions shown, adjacent leaves are center grooved and are interfitted as at 60, the assembly being completed by the spring band 62 embracing the leaves of the spring and being correspondingly grooved so that the spring band interfits with upper and lower plates of the leaf spring assembly. It will of course be understood that similar constructions may be used, such as a completed boss or rib formed adjacent the center of the plates or extending completely across the plates. The coil springs 66 in each of the modifications are seated on the spring seats 58 provided on the side frame and embrace the positioning dowel 10, the metallic or resilient upper seat I2 being interposed between the coil spring 66 and the lower plate of the leaf spring assembly, the positioning dowel M serving to position the seat I2 in respect to the coil spring.

In the construction shown in Figure 4 of the drawings, the lower plate E6 of the leaf spring assembly is provided with spaced lugs 18 adapted to abut and position the spring band 62.

If desired, the leaves of the leaf springs shown in Figures 1 and 2 may be secured together as disclosed in Figures 5 to 28 inclusive. In the embodiment shown in Figures 5- to inclusive, the leaves I00 of the leaf spring are formed with interfitting grooves or recesses I02 substantially at the center thereof, these leaves being embraced by a substantially U-shaped band I04 provided with a transverse offset I06 fitting the groove of the uppermost leaf whereby the band is interlocked therewith-to prevent displacement.

The band I04 is provided with the depending legs I08 and H0 threaded at the end thereof and secured in position by the cotter pins II8 to prevent the nuts from becoming lost or accidentally removed from position on the legs of' the. band. By this particular arrangement the leaves of the spring are interlocked and the spring band interlocked with the leaf spring assembly. Y

Figures 11 to 16 inclusive disclose another type of leaf spring construction with a spring band adapted to hold the leaves in interlocked relation to prevent their displacement. In this embodiment, leaves I20 are offset as at I22 adjacent the center thereof to provide grooves whereby the leaves are interlocked with one another. The spring band I24 is of the construction disclosed in Figure 14 of the drawings and is adapted to be inserted over the assembled leaves, the top member thereof being'formed witha recess I26 receiving the offset I22 of the uppermost leaf. The band opposite the recess 526 is formed with a threaded opening I28 adapted to receive the set screw I62, the end of which engages within the recess I32 of a cap I34 which has the pro-' jection I36 engaging in the recess formed by the offset I22 of the lowermost leaf. The leaves are interlocked and held together by tightening the set screw I30, which also holds the band in locked relation with respect to the leaves. Removal of the set screw I30 is prevented by means of a wire or the like I38 passing through a transverse opening in the head of the set screw I30 and embracing the lower portion of the band I24.

In Figures 17 to 19 inclusive, the leaves of the spring are formed with interlocking offsets ME) corresponding to the offsets shown in the embodiment disclosed in Figure 6. The band in'this embodiment is' formed in two parts I42 and I44 having-aligned openings I46 and I48, respectively, which are adapted to receive the bolts I50. These bolts are engaged by nuts I 52 between which and the upper band member N54 is a plate I55 which may have the corners I56 and I 58 turned up- 7 wardly into engagement with the fiat sides of the nuts I52 to prevent their accidental removal. The lower member I42 is further formed with the projections I60 and I62 adjacent the heads of the bolts and adapted to engage therewith to prevent rotation of the bolts when the ends are being tightened. As clearly shown in Figure 18 of the drawings, the upper band member I64 is formed with a protuberance I64 engaging the recess formed by the offset I40 of the upper leaf of the spring, while the lower band member M2 is formed with a recess I66 adapted to receive the offset of the lower leaf of the spring Whereby the band is held in position upon tightening of the nuts I52.

Figures 20 to 23 inclusive disclose still another form of construction for the spring band, the band in this instance comprising upper and lower parts I68 and I10, both of which are substantially U-shaped in construction and'adapte'd to embrace the leaves of the leaf spring assembly. Each of the leaves H2 is formed with spaced openings I14 and I16, adapted to be aligned when the leaves are assembled and through which pass bolts I18 and I88, respectively, the heads of these bolts being received within the recesses I82 formed in the upper band member I68, the shank of the bolts passing through the spaced apertures I84 in the lower band member I18; Threaded on the lower ends of these bolts are the nuts I86, between which and the lower band member III] is a plate I88 which has its opposite ends turned. downwardly, as at I98 and I92, into engagement with the flat face of the nuts I88 to prevent their accidental removal.

In Figures 24 to 28 inclusive is disclosed a spring assembly particularly adapted for use in a side frame construction as shown in Figure 2 of the drawings. In this embodiment, the leaves of the spring are formed with apertures I94 disposed in alignment when the leaves are assembled to receive a bolt I96, this bolt passing downwardly through openings in the band I98 and a plate 280 and being engaged at its lower end by the nut 202 which engages the lower leaf of the spring assembly and is held in place by the lock nut 284. Spring band I98 is of the construction shown in Figures 26 to 28 inclusive, and has a part 288 depending from the upper plate portion 208 which is adapted to engage the edge of a plurality of the leaves to prevent lateral displacement thereof. Depending from the other side of the topplate 208 is a flange 2H3 embracing the edge of the first leaf or two of the assembly for holding the band in position whereby the depending part 206 prevents lateral displacement of the leaves of the spring. Transversely disposed in relation to the top plate 288 of the spring band is the plate 288 which is formed with the depending flanges 2H! and 2I2 which engage in openings formed in the load carrying blocks 2M and ZIS,

40 each of which may be provided with a substantially lower leaf spring engaging surface 2 I8 and the upper crowned surface 220 for engaging a load carrying member for supporting the same. However, it is to be understood that these load carrying blocks 2 I4 and 2I6 may be constructed in accordance with the disclosure in Figure 2 of the drawings to provide the spaced points of support as shown in that figure.

Each of the embodiments shown in Figures 5 to 28 inclusive discloses an advantageous method of securing together the leaves of an elliptic spring. All of these embodiments permit the leaves of the semi-elliptic spring to be taken apart without destroying the band, which is impossible with the usual form of spring band. With the designs of spring bands shown herein leaves of a semi-elliptic spring may be taken apart as often as is necessary and no part need be destroyed in the process. It is often necessary to dismantle leaf springs either to remove a broken leaf or to renew the camber of the leaves. With bands of the designs illustrated herein such work may be done without destruction of the bands.

In each of the embodiments shown in Figures 3 to 28 inclusive, the bolster 28, or other load carrying member, may be supported by load carrying blocks 38 and 32, and the bolster may embrace the leaf spring assembly and cooperate with the spring band 62 whereby the same is positioned. In these embodiments, the load is transmitted from the bolster or other load carrying member at a plurality of spaced points to the leaf spring assembly which is in turn supported immediately below the said spaced points thus compressing the leaves of the elliptic spring whereby the maximum percentage of frictional absorption within the spring is obtained. This provides a simplified construction with the maximum efficiency, and is particularly adapted for use in four-wheel car trucks.

While I have herein described and upon the drawings shown illustrative embodiments of the invention, itis to be understood that the invention is not limited thereto but may comprehend other constructions, arrangements of parts, details and features without departing from the spirit of the invention.

I claim:

1. A spring assembly comprising a leaf spring serving as a beam to support a portion of a superimposed load, and means cooperating therewith to increase the energy absorption of said leaf spring and serving to support the remainder of said superimposed load.

2. A spring assembly comprising a leaf spring serving as a beam to support a portion of a superimposed load, and resilient means cooperating therewith toincrease the energy absorption of said leaf spring and serving to support the remainder of said superimposed load.

3. Load supporting means comprising a group of coil and leaf springs cooperating under load to increase the energy absorption of the leaf springs, said leaf springs serving as beams to support a portion of the load and the coil springs serving to support the remainder of the load.

4. A spring assembly comprising a leaf spring serving as a beam to support a portion of a superimposed load, and a resilient member cooperating therewith to increase the energy absorption of said leaf spring and serving to support the remainder of said superimposed load.

5. A spring assembly comprising a leaf spring serving as a beam to support a portion of a superimposed load, and a coil spring cooperating therewith to increase the energy absorption of said leaf spring and serving to support the remainder of said superimposed load.

6. A spring assembly comprising a leaf spring serving as a beam to support a portion of a superimposed load, and a coil spring cooperating therewith to increase the energy absorbing capacity of the leaf spring as the load is increased and serving to support the remainder of said superimposed load.

'7. A spring assembly comprising a semi-elliptic leaf spring serving as a beam to support a portion of a superimposed load, and resilient means cooperating therewith to increase the energy absorption of said leaf spring and serving to support the remainder of said superimposed load.

8. A spring assembly comprising a semi-elliptic leaf spring serving as a beam to support a portion of a superimposed load, and a coil spring cooperating therewith to increase the energy absorption of said leaf spring and serving to support the remainder of said superimposed load.

9. Load supporting means comprising a group of coil and semi-elliptic leaf springs cooperating under load to increase the energy absorption of the leaf springs, said leaf springs serving as beams to support a portion of the load and the coil springs serving to support the remainder of the load.

10. In combination, load carrying means, a leaf spring serving as a beam to support a portion of the load from said load carrying means,

and means cooperating with said leaf spring to increase the energy absorption of said leaf spring and serving to support the remainder of said load.

11. In combination, load carrying means, a leaf spring serving as a beam to support a portion of the load from said load carrying means, and resilient means cooperating with said leaf spring to increase the energy absorption of said leaf spring and serving to support the remainder of said load.

12. In combination, load carrying means, a leaf spring serving as a, beam to support a portion of the load from said load carrying means, and a resilient member cooperating with said leaf spring to squeeze the leaves together with a force which increases as the load increases and serving to support the remainder of said load.

13. In combination, load carrying means, a leaf spring serving as a beam to support a portion of the load from said load carrying means, and a, resilient member cooperating with said leaf spring to squeeze the leaves together with a force which varies directly with the load and serving to support the remainder of said wheel.

14. In a load carrying device, the combination of a leaf spring, a load carrying member, means for supporting said member at spaced points on said spring, and resilient means engaging said leaf spring at spaced points to increase the energy absorption of said leaf spring.

15. In a load carrying device, the combination of a flexible member, a load carrying member, and load carrying means for transferring load from one of said members to the other, said means including a plurality of members each supporting said last-named member at a single point and being supported at spaced points by said firstnamed member. 7

16. In a load carrying device, the combination of a leaf spring, spaced load carrying blocks disposed thereon, a load carrying member supported thereon, and resilient means engaging said leaf spring at spaced points to increase the energy absorption of said leaf spring.

1'7. In a load carrying device, the combination of a leaf spring, spaced load carrying blocks disposed thereon, a load carrying member supported thereon, and coil springs engaging said leaf spring at spaced points to increase the energy absorption of said leaf spring.

18. In a load carrying device, the combination of a, leaf spring, spaced load carrying blocks disposed thereon, a load carrying member supported thereon, said blocks having arcuate surfaces cooperating with said load carrying member, and coil springs engaging said leaf spring at spaced points to increase the energy absorption of said leaf spring and serving to support a portion of the load.

19. In a leaf spring assembly, the combination of a plurality of spring leaves, means for securing the leaves of said assembly together, load carrying blocks disposed in spaced relation to said means and cooperating with said assembly, said means having means for holding said blocks in a substantially fixed position with respect to said spring leaves irrespective of the deflection thereof.

ALFRED H. OELKERS.