US2097523A - Snubber - Google Patents

Description

N0v.2,1937. I w. c. HEDGCOCK ET AL ,0 7 5 SNUBBER Filed Nov. 10, 1933 3 Sheets-Sheet 1 Invefit'm' William GHeggcocK Nov. 2, 1937. 'w. c. HEDGCOCK El AL 2,097,523 smam Filed. Raw. 10-, 1953 5 Sheets-Shad: 2 v

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Patented Nov. 2, 1937 SNUBBEB 'William C. Hedgcock, Wilmette, and David 1!.

light, Evanston, 11L, asaignors, by meme assignments,

to Oardwell-Westinghouse Company, a corporation of Delaware Application November 18, 1983, Serial No. 887,888

1; Claims. (01. 201-9) This invention pertains to snubber springs and more particularly to snubbing spring arrangements adapted for use with railway car trucks.

It is an object of this invention to provide a spring assembly embodying shock absorbing and snubbing features.

Another object is to provide snubbing springs which can be substituted-for existing springs in railway car trucks.

Yet another object is to provide resilient supporting means for the load carrying member of a car truck for dampening the movement of said load carrying member.

With these and various other objects in view, the invention may consist of certain novel features of construction and operation as will bemore fully described and particularly pointed out in the specification, drawings and claims appended hereto.

In the drawings, which illustrate embodiments of the device and wherein like reference characters are used to designate like parts Figure 1 is a sectional elevation of one form of snubbing spring arrangement embodyingthe invention;

Figure 2 is a top plan view of the snubber arrangement shown in Figure 1;

Figure 3 is a sectional elevation of a modified form of snubber arrangement;

Figure 4 is a sectional elevation of another modified form of snubber arrangement;

Figure 5 is a sectional plan view taken substantially in the plane as indicated by the line 5-5 of Figure 4;

Figure 6 is a sectional elevation corresponding to Figure 4 showing the snubber arrangement in compressed position;

Figure '7 is a sectional elevation of still another modified form of snubber;

Figure 8 is a sectional plan view taken substantially in the plane as indicated by the line 8-8 of Figure '7;

Figure 9 is a sectional elevation of a further modified form of snubber arrangement.

Referring first of all more particularly to the snubber arrangements illustrated in Figures 1 to 3 inclusive, the devices consist essentially of a helical spring 28 preferably formed from a square or rectangular steel bar. Within the spring so formed a friction device 22 is provided including a plurality (shown as four) of rectangularly disposed frictional segments or shoes 24, the outer surfaces of which make contact. with the inner surface of the spring 28. The segments 24 are nominally of cylindrical shape in their assembly ments 24.

within the helical spring, each segment being provided at each end thereof with the conical wedging surface 28, against which is mounted the wedging ring 28 having cooperative wedging surfaces 88 engaging the surfaces M of the scs- 6 ments 24. The two wedging rings 28 are forced away from each other by means of the coil spring 22 whereby there is a constant tendency for the friction segments 24 to expand away from each other and make a tight contact between their 18 outer friction surfaces 84 and the inner surfaces of the spring 28. I I

In the construction illustrated in Figure 3, end plates 86 are provided on the spring 28, being positioned in the spring by means of the flange 15 38 and provided with a depressed end portion 48 for accommodating the head of the bolt 42, the bolt 42 passing through and being loosely connected to the friction elements or, wedging rings 88. By providing the bolts 42 the friction ele- 20 ments are kept within the center portion of the helical spring and the bolts prevent the wedging rings from moving away from the ends of the coil spring to the extent limited by the length of the bolts whereby the entire assembly is prevented 2 from becoming disassembled and the friction device is prevented from moving to either end of the coil spring.

With these constructions it will be noted that when the helical spring 28 is compressed so that 39 the upper surfaces move towards the lower elements a considerable amount of sliding takes place between the inner surfaces of the helical spring and the outer surfaces of the friction segv The amount of energy absorbed by such friction may be varied by the capacity of the coil spring 82 which constitutes the resilient means controlling the pressure between the friction surfaces 28 and 38 of the friction members 24 and 28 respectively. By this mechanism the 4. compression of the helical spring 28 is caused to require greater force than the resilient reaction of the helical spring 28, and the release of this helical spring is further retarded by the same frictional medium.

Referring now to the constructionillustrated in Figures 4 to 6 inclusive, the device consists of the helical spring 44 shown as formed from a bar of circular section. The spring is provided at each end with the spring caps 48, said spring caps being provided with friction elements or shoes 48 extend ng within the helical spring, the friction elements each having conical shaped or tapered bores 58 against which surface friction elements 55 '52 are seated. The friction elements are shown as four in number and are mounted within the bore 50 having complementary friction surfaces 54 cooperating therewith. Each of the friction elements is provided with the conical friction surfaces 56 against which the friction 0r wedging rings 58 are seated, said rings being provided with complementary friction surfaces 60 having frictional engagement with the surfaces 56, the rings being held tightly against said friction surface by means of the coil spring 62 disposed between the spaced wedging rings. Bolts 64 are seated in the recesses 66 provided in the spring caps and are loosely connected to the wedging rings 58v extending. through a' suitable aperture provided therein, the bolts serving to prevent disassembiy of the entire device and to position the friction wedging assembly therein, the spring 62 being positioned by means of the boss provided on rings 58 through which the bolts pass.

In this construction it will be seen that when the load is applied to the assembly at the ends, and the helical spring is compressed, the spring caps are caused to travel towards each other thereby causing the conical surface 50 to slide on the complementary surfaces 54 of the friction elements 52. That is, the friction elements are forced toward each other causing an inner assembly of smaller diameter to be formed. Such contracting of the assembly of friction elements is resisted by the resiliency of the coil spring 62 and the frictional contact between the surfaces 56 and 60. The force required to compress the unit depends, first on the resistance offered by coil spring 44; and second, the friction developed between the outer surfaces 54 of the frictiOn elements .52 and the surface or inner bore ill of the friction elements 48 integrally formed on the spring caps 46. This friction in turn depends upon the-force exerted by coil spring 02 and the friction between the surface 60 of conical weds'ing ring 58 and the surface 5! of the friction elements 52. When the helical spring assembly is being compressed the force must overcome the resiliency of the spring, the'friction between the surfaces 50 and 54 and the friction between the surfaces 56 and 60. When the force compressing the helical spring 54 is released these frictional elements retard the resilient pressure exerted by the spring. Thus a snubbing as well as a shock absorbing spring assembly is provided.

Referring now more particularly to the constructions illustrated in Figures 7 to 9 inclusive,

the assemblies also consist of the helical spring 68 preferably made of a bar of square or rectangular section whereby a substantially cylindrical surface is provided by the inner bore of the spring. Within the spring there are mounted two spaced longitudinally disposed friction elements or shoes III the outer faces of which are complementary .to the inner surface of'the spring 68. The two friction elements III are provided with spaced helical spring seats 12 adapted to receive the transversely disposed coil springs 14 positioned thereon by means of the dowels 16 whereby the friction elements are resiliently forced apart from each other and against the inner bore of the helical spring to the extent that pressure is exerted through the compression of the transverse springs 14 between the elements III.

In the construction illustrated in Figure 9, the elements 10 are shown provided with the recesses 18 whereby the end lips or flanges Ill are adapted to engage outwardly disposed cooperating flanges 82 on the end caps 84 whereby the friction elemehts are maintained in a central position within the spring assembly. When the helicalspring is compressed the projection or flange 82 will go downwardly in the recess 18 and if the elements 10 also move downwardly through action of its contact with the bore of the spring 10, then the projection 82 will pull the friction elements back into their original position when the spring assembly is released.

In the constructions illustrated, the spring group may be provided in a. bolster opening or window of a truck side frame to resiliently support the bolster transom or other load carrying member disposed therein, the action of the devices serving to act as a. shock absorber and a snubber for retarding vertical movements of the load carrying member with respect to the associated side portion.

Although the devices are shown as spring assemblies, it is of course to be appreciated that they may be incorporated into the side frames and load carrying members, as for example the spring caps 4i illustrated particularly in Figures 4to 6. inclusive, may be integrally formed on the load carrying member and side frames whereby positioning means are formed for the helical springs and friction elements disposed within the members 48 as already described.

It is to be understood that we do not wish to be limited by the exact embodiments of the device shown, which are merely by way of illustration and not limitation, as various and other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims We claim:

1. In a. cushioning device, the combination of a spring having a central opening, friction shoes disposed in said opening and having sliding cooperation with said spring, said shoes having end wedging portions, wedging members having fric-' tion surfaces contacting said wedging portions, resilient means interposed between said wedging members urging said members toward said wedging portions, abutment means engaging the ends of said spring, and means connected to said abutments and said wedging members for maintaining said shoes, wedging members and resilient means in position with respect to said spring.

2. In a cushioning device, the combination of a spring formed from a bar of substantially rectanguiar section and having a central opening, friction shoes disposed in said opening and having sliding cooperation with said spring, said shoes having end wedging portions, wedging members having friction surfaces contacting" said wedging portions, resilient means interposed between said wedging members urging said members toward said wedging portions, abutment .means engaging the ends of said spring, and

means connected to said abutments and said wedging members for maintaining said shoes. wedging members and resilient means in position with respect to said spring.

3. In a cushioning device, a load supporting helical spring, a cap .at each end of said helical spring, a plurality of friction shoes engaging the interior of said spring, said shoes being of a length less than said spring, each shoe being positioned in the central portion of said helical spring and extending toward each end thereof, means for resiliently forcing said shoes laterally into frictional engagement with the interior of said spring, and rigid means operatively connected with said caps for positioning said shoes in both directions relative to said spring during the ex pansion of said spring after compression. I 4. In a cushioning device, a load supporting helical spring, friction surfaces associated with said spring, a plurality of shoes within said spring for engaging said surfaces, means including springs for forcing said shoes radially outwardly into a substantially constant frictional engagement with said surfaces, and rigid means for positioning said shoes within said helical spring;

5. In a'cushioning device, a load supportinghelical spring, friction shoes within said spring,

spring members engaging said shoes and extending transversely of said helical spring for forcing said shoes radially outwardly with a substantially constant pressure into frictional engagement with said spring, caps for the ends of said spring, and means on said caps engaging said shoes for positioning the same within said spring.

6. In a cushioning device, a load supporting helical spring, means, including a spring member and friction elements within said .helical spring for frictionally resisting the compression of said spring, said frictional resistance being substantially constant, and means for positioning said first-named means within said helical spring. 7. In. a cushioning device, the combination of a load supporting helical spring formed from a 7 bar of substantially rectangular section wherebya substantially cylindrical bore is provided, friction shoes disposed in said bore and having arcuate surfaces cooperating over their entire width with said-spring, said shoes having end wedging portions, wedging members having tapered friction surfaces contacting said wedging portions, and a spring interposed between said wedging members urging said memberstoward said wedging portions for forcing said shoes radially into frictional contact with said helical spring at a substantially constant pressure.

8. In a cushioning device, the combination of a load supporting helical spring wound to provide a cylindrical, bore, shoes of less length than saidspring. disposed -in said bore and having arcuate surfaces frictionally engaging said spring throughout their length, each of said shoes having a wedgingportion on each end thereof, wedging members having conical friction surfaces contacting said wedging portions, and a resilient means interposed between said wedging members [urging said members toward said wedging portions.

9. In a cushioning device, the combination of a load supporting helical spring formed from a bar of substantially rectangular section whereby a substantially cylindrical bore is provided, friction shoes disposed in said bore and having arcuate surfaces frictionally engaging said spring throughout their entire length, said shoes having end wedging portions, tapered wedging members having friction surfaces contacting said wedging portions, a spring interposed between said wedging members urging said members toward said wedging portions with a constant pressure, and

means having cooperative relation with said wedging members for maintaining said shoes, said wedging members and said last named spring in a predetermined position with respect to said first named spring.

10. ma cushioning device, the combination of a load supporting spring having a central cylindrical opening, friction shoes disposed in said opening and having arcuate surfaces cooperating over their entire width with said spring for frictionally resisting the compression of said spring, each shoe having a wedging portion on each end thereof, wedging members having friction surfaces contacting said wedging portions, resilient means interposed between said wedging members urging said members toward said wedging portions, and means for maintaining said shoes,

wedging members and resilient means in position between the ends of said first named spring with respect to said spring. 7

11. In a cushioning device, a load supporting helical spring, a cap for each end of said spring,

rigid means connected to each cap extending into 1 said spring, friction shoes, said means engaging said shoes for positioning the same within said spring, and means including a spring element for forcing said shoes radially outwardly for frictionally engaging said spring for yieldingly resisting the compression thereof.

' WILLIAM C. HEDGCOCK.

DAVIDM. HGHT.

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