Snubbed spring group

Abstract

Claims

Jan. 14, 1958 c. E. TACK 2,819,395 SNUBBED SPRING GROUP Filed March 22, 1956 '3 Sheets-Sheet Q Jan. 14, 1958 c. E. TACK 2,819,895 SNUBBED SPRING GROUP Filed March 22, 1956 -5 Sheets-Sheqt 2 22 1 INVENTOR; 20 20 caJL E. 11149 Jfi SNUBBED SPRING GROUP Carl E. Tack, Chicago, 111., assignor to American Steel Foundries, Chicago, 111., a corporation of New Jersey Application March 22, 1956, Serial No. 573,234 Claims. (Cl. 267-9) This invention relates to friction snubbing devices and more particularly to a novel spring group incorporating such a device, said group being adapted for support by a railway car truck side frame and being adapted to support the truck bolster for limited vertical, horizontal and rotational movement relative to the frame and is a continuation-impart of my application bearing Serial No. 248,695, filed September 28, 1951, now abandoned. Gne type of snubbing device which has been used in the prior art as exemplified by United States Patent 2,360,262, utilizes top and bottom followers each having V-shaped friction surfaces converging downwardly and upwardly, respectively, for engagement with complementary surfaces of a pair of friction shoes having one or more springs compressed therebetween. In such arrangement downward or lateral displacement of the top follower in response to bolster movement results in increased compression of the shoe actuating springs. However, it has been known for years that such prior art devices have short life in service due to breakage and excessive wear of the parts, and accordingly, this type of snubber has been considered inherently inadequate for railway service. According to the present invention, it has been discovered that a primary cause for breakage and excessive Wear of such devices is due to lateral bolster impacts transmitted to the top follower when the latter is in a position of substantial downward displacement from its normal position. It has been further discovered that the shoe actuating springs upon downward displacement of the top follower exert such extreme forces to resist lateral displacement of the follower, under such conditions, that failure of the snubber parts frequently results. Accordingly, a primary object of the present invention is to devise a spring group, such as above described, wherein lateral displacement of the followers relative to each other does not cause compression of the shoe actuating spring means. A further object of the invention is to lock each shoe with one of the followers against substantial relative lateral displacement and to provide means to resist lateral displacement of the shoe relative to the other follower by substantially constant friction for any given amount of vertical displacement of the top follower. Still another object of the invention is to prevent cocking or tilting of the shoes on an axis parallel or coaxial with the compressional axis of the shoe actuating springs. My invention embodies other novel features, details of construction and arrangement of parts which are hereinafter set forth in the specification and claims and illustrated in the accompanying drawings, wherein: Figure 1 is an end view of my spring group, half in section, the section being taken in the transverse vertical plane indicated by the line 1-1 of Figure 2. Figure 2 is a side elevational view of my spring group, half in section, the section being taken in the longitudinal vertical plane indicated by the line 2-2 of Figure 1. asiasas Patented Jan. 14, 1958 ice Figure 3 is a composite top plan view, the lower half of this figure being a top plan view of the spring group, and the upper half of the figure being a top plan view of the bottom follower. Figure 4 is a side elevational view of one of the identical friction shoes shown in Figures 1, 2, 3 and 10. Figure 5 is a top plan view of the friction shoe. Figure 6 is a rear elevational view taken from the left as seen in Figure 4. Figure 7 is a front elevational view taken from the right as seen in Figure 4. Figure 8 is a fragmentary sectional view taken in the plane indicated by the line 88 of Figure 4. Figure 9 is a fragmentary sectional view taken in the plane indicated by the line 99 of Figure 4. Figure 10 is a sectional view of a modified form of my spring group, the section being taken in the transverse vertical plane bisecting the spring group, and Figures 11 through 14 illustrate alternate embodiments of the friction shoe shown in Figures 49, Figures 11 and 13 being side elevational views corresponding to Figure 4, and Figures 12 and 14 being fragmentarysectional views taken in the planes indicated by the lines 12-12 and 1414 of Figures 11 and 13, respectively, and corresponding to Figure 8. Describing the invention in detail with reference first to Figures 1, 2 and 3, wherein like reference characters denote corresponding parts, the preferred form of my novel spring group comprises'top and bottom followers 2 and 4, respectively. Between these followers are interposed vertically disposed telescoped coil springs 6, 6 and 8, 8 seated at each of the corners thereof. Transversely and medial the ends of followers 2 and 4 is disposed my novel snubbing device comprising a pair of wedgeshaped friction shoes 10, 10 which are yieldably constrained in frictional engagement with followers 2 and 4 by a pair of horizontally disposed telescoped coil springs 12 and 14. Bolt and nut assemblies 16, 16 disposed at the ends of the followers maintain the spring group in assembled relationship. Describing now the top follower 2, numeral 18 indicates a top plate having spring seats or cubicles 20, 20 arranged one at each corner thereof. Each cubicle is bordered by an inturned external flange 22 extending along the perimeter of plate 18 and merging with a substantially vertical transverse web 24. A Y-shaped web 26 disposed longitudinally of plate 18 interconnects each flange 22 and web 24. Cubicles 20, 20 preferably snugly seat springs 6, 6 and 8, 8 therein. A pair of longitudinally aligned assembly lugs 28, 28 each having an aperture 30 therein are preferably connected to the flanges 22, 22 at the opposing ends of plate 18. A pair of spaced and transversely aligned downwardly diverging V- shaped friction walls 32, 32 depend from the sides of plate 18; these walls are also connected to the transverse webs 24, 24. Reinforcing webs 34, 34 preferably connect friction walls 32, 32 to transverse webs 24, 24. Friction walls 32, 32 are provided with V-shaped friction surfaces 36, 36 for engagement with shoes 10, 10 as hereinafter more fully described. Bolster locating pins 38, 38 are formed on the top side of plate 18. Friction walls 32, 32 and the transverse webs 24, 24 form a housing compartment that contains the upper portion of the friction device hereinafter described. Describing now the similarly formed bottom follower 4, numeral 40 indicates a bottom plate having springseats or cubicles 42, 42 arranged one at each corner thereof. Each cubicle is bordered by an inturned external flange 44 extending along the perimeter of plate 40 and merging with a substantially vertical transverse web 46. A longitudinally disposed web 48 interconnects flange 44 and web 46. A spring positioning lug 47 is formed on each of the transverse webs 46, 46 in cubicles 42, 42. Cubicles 42, 42 preferably snugly seat springs 6, 6 and 8, 8 therein. A pair of longitudinally aligned assembling lugs 50, 50 each having an aperture 52 therein, are preferably connected to flanges 44, 44 at the opposing ends of follower 4. A pair of spaced and vertically disposed gussets 54, 54 having aligned apertures 56, 56 therein are connected to each of the lugs 50, 50 and flanges 44, 44. A pair of spaced and transversely aligned upwardly diverging fiat friction walls 58, 58 are connected to the sides of plate 40, these walls are also connected to transverse webs 46, 46. Reinforcing webs 60, 60 are preferably connected to friction walls 58, 58 and webs 46, 46. Friction walls 58, 58 are provided with flat, substantially planar friction surfaces 62, 62 for engagement with shoes 10, 10 as hereinafter more fully described. Side frame locating pins 64, 64 are formed on the underside of plate 40, and drain holes 66, 66 and 68, 68 are cored therein. Friction walls 58, 58 and the spaced transverse webs 46, 46 form a housing compartment that contains the lower portion of the friction device hereinafter described. Describing now my novel friction shoe 10 and having reference to Figures 4 through 9, numerals 74 and 72 indicate recessed spring seats adapted for the seating of a pair of telescoped coil springs 12 and 14, respectively, and numerals 76 and 78 indicate merging friction surfaces that are generally wedge-shaped. Surface 76 is V-shaped and complementary in form to the friction surfaces 36, 36 formed in the top follower 2. Surface 78 is flat and complementary in form to the friction surfaces 62, 62 formed in the bottom follower 4. Preferably the walls 24, 24 of the top follower snugly confine the upper ends of the shoes 10 to prevent cocking or tilting thereof on an axis parallel or coplanar with the compressional axis of the springs 12 and 14; however, if desired, the walls 24 may be spaced the same distance from each other as the walls 46, inasmuch as the V- shaped surfaces 36 and 76 in combination with the flat surfaces 62 and 78 will normally prevent such tilting of the shoes. With reference to Figures 1, 2 and 3, it will be noted that my novel composite spring group is maintained in assembled relationship by the bolt and nut assemblies 16, 16. Each of these assemblies comprise a bolt 82preferably welded to lug 28, as at 84, and a nut 86 fixed to bolt 82 by a weld 88 and a washer 90 secured to nut 86 by a weld 92. With the parts arranged as shown and described, my novel spring group may be placed in service, that is, inserted in a railway car truck side frame (not shown) to support the bolster load, the longitudinal axis of the spring group being disposed parallel to the longitudinal axis of the bolster. With the bolster load applied the spring group is compressed causing the disengagement of washers 90, 90 and the related lugs 50*, 50 to permit the unobstructed oscillation of the spring group. The oversized apertures 52, 52 in lugs 50, 50 permit angling and horizontal displacement of top follower 2 relative to bottom follower 4. Vertical oscillations of the spring group are arrested or dampened by the frictional forces developed at the respective friction surfaces as a result of the opposing normal forces acting at these frictionally engaged surfaces. These opposing forces comprise respective components of the bolster load opposed by respective components of the reaction forces exerted by springs 12 and 14 which will be obvious to those skilled in this art. The lateral impacts of the bolster are opposed by the frictional forces that develop as shoes 10, 10 slide against surfaces 62, 62 between the transverse Webs 46, 46. These impacts are also opposed by the reaction forces exerted by the ends of springs 6, 6 and 8, 8 against their respective snugly seating cubicles. Shoes 10, 10 never contact webs 46, 46 because the bolster motion is checked by the engagement of the bolster gibs and the related side frame columns before possible engagement with either of webs 46, 46. The frictional forces that develop between the respective friction surfaces in response to the vertical oscillations of the spring group depend upon the magnitude of the forces exerted by springs 12 and 14, on the value of the cocflicient of friction between the respective friction surfaces and on the magnitude of the included angle between the friction shoe surfaces 76 and 78. The frictional forces that develop between the flat friction surfaces of the bottom follower and the respective abutting fiat friction shoe surfaces in response to the lateral bolster thrusts depend upon the magnitude of the forces exerted by springs 12 and 14, on the value of the coel'iicient of friction between the respective friction surfaces and on the magni* tude of the included angle between the friction shoe surfaces 76 and 78. The foregoing friction parameters may be selected in accordance with the damping problem. In the modification of Figure 10, parts corresponding to those previously described are identified by corresponding numerals. In this embodiment each follower is formed with one flat friction wall 58 and one V-shapcd friction wall 32, the walls 58 and 32 of respective followers being preferably disposed at diagonally opposite upper and lower corners of the device, as illustrated. It will be understood that the walls 24 and 46 are spaced from the portions of the shoes which engage the flat surfaces 62 of the walls 58 to accommodate relative lateral movement between the shoes and the surfaces 62 as heretofore described in connection with Figures 1 to 9. Describing now the friction shoes illustrated in Figures 11-14, it will be understood that except for the modification hereinafter described the shoes are identical with the shoe shown in Figures 4-9 and parts corresponding to those of Figures 4-9 are identified by corresponding numerals. Referring to Figures 11-14, it is seen that the friction shoes illustrated differ from the earlier described embodiment only in the configuration of the friction surfaces 76. In Figures 11 and 12 the surface 76 is formed of multiple V-shaped depressions and raised portions, while in Figures 13 and 14, the surface 76 is arcuate. It will be understood that the friction walls 32 of the followers must be provided with friction surfaces 36 (Figures 1 and 10) having complementary configurations, that is, if a shoe having a multiple -shaped surface 76 is used, the corresponding surface 36 must be of multiple V-shape; whereas, if a shoe l1avin an arcuate friction surface 76 is used, then the associated surface 36 must be arcuate. The important consideration is that complementary nonplanar, or crowned, friction surfaces must be provided which will resist lateral force components and thereby prevent horizontal movement of the shoe relative to the follower but which will accommodate upward and downward movement of the shoe relative to the follower. Although the preferred forms of crowned or nonplanar friction surfaces are illustrated in Figures 8, 12 and 14, other nonplanar forms might conceivably be utilized and still fall within the scope of the invention. For example, the surface 76 of Figure 12 might be undulating or S-shaped and the surface 76 of Figure 14 might be curvilinear but not arcuate. I claim: 1. A spring group for a railway car truck comprising a top follower having a cubicle-like spring seat at each end thereof, a pair of transversely aligned and downwardly diverging friction walls depending from said follower, a bottom follower having a cubicle-like spring seat at each end thereof, a pair of transversely aligned and upwardly diverging friction walls connected to said bottom follower, a plurality of coil springs between said top and bottom followers snugly seated in said spring seats, a pair of transversely aligned wedge-shaped friction shoes each in complementary frictional engagement with the respective walls of said top and bottom followers, a compressed resilient member seated against said shoes, and transverse webs connected to said top follower and snugly engaged with said shoes and operative to prevent angling of said shoes relative to the engaged walls, said shoes being slidably movable in both horizontal and vertical directions against the friction walls of said bottom follower. 2. A spring group for a railway car truck comprising a top follower having a cubicle-like spring seat at each end thereof, a pair of transversely aligned and downwardly diverging friction walls depending from said follower, one of said walls being V-shaped and the other fiat, a pair of spaced transverse webs connected to said follower and walls, a bottom follower having cubiclelike spring seats at each end thereof, a pair of transversely aligned and upwardly diverging friction walls connected to said bottom follower, one of said second mentioned walls being V-shaped and the other fiat, a pair of transverse webs connected to said bottom follower and walls, a plurality of coil springs between said top and bottom followers snugly engaged with said spring seats, the V-shaped and fiat walls of said top being diagonally opposed to the ll-shaped and fiat walls of said bottom follower, respectively, a pair of transversely aligned wedgeshaped friction shoes each in complementary engagement with the V-shaped wall of one follower and flat wall of the other follower, and a compressed coil spring seated against said shoes, said shoes being slidably movable in a horizontal direction against the flat friction walls. 3. A damping device comprising a top follower, a housing compartment formed on the inside of said follower, said compartment comprising a pair of transverse webs interconnected by a pair of spaced and downwardly diverging friction walls, a bottom follower, a compartment formed on the inside of said bottom wall and comprising a pair of transverse webs interconnected by a pair of spaced and upwardly diverging friction walls, certain of said walls being arranged in substantially V-shaped formations and certain other of said walls being flat, a pair of friction shoes in wedge engagement with said top and bottom follower walls, compressed resilient means between said shoes, said shoes being slidably movable in both horizontal and vertical directions against certain of said friction walls. 4. A damping device comprising a top follower, a pair of transversely aligned and downwardly diverging friction walls depending from said follower, one of said walls being V-shaped and the other flat, a pair of transverse webs connected to said follower and walls, a bottom follower, a pair of transversely aligned and upwardly diverging friction walls connected to said bottom follower, one of said walls being V-shaped and the other fiat, a pair of transverse webs connected to said bottom follower and walls, the V-shaped and flat walls of said top follower being diagonally opposed to the V-shaped and flat walls of said bottom follower, respectively, a pair of transversely aligned wedge-shaped friction shoes each in complementary engagement with the V-shaped wall of one follower and flat wall of the other follower, and compressed resilient means seated against said shoes, said shoes being slidably movable against said friction walls. 5. A damping device comprising a top follower, a pair of transversely aligned and downwardly diverging friction walls depending from said follower, one of said walls being V-shaped and the other fiat, a pair of spaced transverse webs connected to said follower and walls, a bottom follower, a pair of transversely aligned and upwardly diverging friction walls connected to said bottom follower, one of said second mentioned walls being V- shaped and the other fiat, a pair of transverse webs connected to said bottom follower and walls, the V-shaped and flat walls of said top follower being diagonally opposed to the V-shaped and flat walls of said bottom follower, respectively, a pair of transversely aligned wedgeshaped friction shoes each in complementary engagement with the V-shaped wall of one follower and flat wall of the other follower, and compressed resilient means seated against said shoes, said shoes being slidably movable in both vertical and horizontal directions against said fiat walls and only in a vertical direction against said V- shaped walls. 6. In a spring group for a railway car truck, top and bottom followers, a coil spring at each side thereof, a damping device housed between said followers and intermediate said coil spring, said damping device comprising at least two pairs of aligned and vertically opposed diverging friction walls formed on said followers, the pair of walls on the top follower being V-shaped and the pair of walls on the bottom follower being flat, a pair of wedgeshaped friction shoes with faces in complementary engagement with said walls, compressed resilient means between said shoes, said followers having aligned assembly lugs at the opposite ends thereof, and securing means extending through said lugs, said shoes being slidably movable in a vertical direction against said top follower walls and in both vertical and horizontal direction against said bottom follower walls. 7. A damping device comprising a top follower, a housing formed on the inside of said follower, said housing comprising a pair of spaced transverse webs interconnected by a pair of spaced and downwardly diverging friction walls, one of said walls being V-shaped and the other flat, a bottom follower, a housing formed on the inside of said bottom follower comprising a pair of spaced transverse webs interconnected by a pair of spaced and upwardly diverging friction walls, one of said second mentioned walls being V-shaped and the other flat, the flat and V-shaped walls of the top plate being diagonally opposed to the flat and V-shaped walls of the bottom plate, the flat wall on one plate being subsatntially vertically aligned with the V-shaped wall on the other plate, a pair of wedge-shaped friction shoes in complementary engagement with said vertically aligned walls, and a compressed resilient member seated against said shoes, said shoes being received within said housings and snugly engaged with the webs adjacent said V-shaped walls and slidably movable in a vertical direciton against said V-shaped walls and slidably movable in both vertical and horizontal directions against said flat walls. 8. A damping device comprising a top follower, a housing formed on the inside of said follower, said housing comprising a pair of transverse webs interconnected by a pair of spaced and downwardly diverging V-shaped friction walls, a bottom follower, a housing formed on the inside of said bottom follower comprising a pair of transverse webs interconnected by a pair of spaced and upwardly diverging flat friction walls, a pair of friction shoes in Wedge engagement with said walls, and a compressed resilient member seated against said shoes, said shoes being received within said housings and snugly engaged with the transverse web of said top follower, said shoes being slidably movable in both vertical and horizontal directions against the friction walls of said bottom follower and slidably movable in a vertical direction against the friction walls of said top follower. 9. A spring group for a railway car truck comprising a top follower, a housing formed on the inside of said follower, said housing comprising a pair of spaced transverse webs interconnected by a pair of spaced and downwardly diverging friction walls, one of said walls being V-shaped and the other flat, a bottom follower, a housing formed on the inside of said bottom follower comprising a pair of spaced transverse webs interconnected by a pair of spaced and upwardly diverging friction walls, one of said second mentioned walls being V-shaped and the other flat, a plurality of coil springs between said followers, the flat and V-shaped walls of the top plate being diagonally opposed to the flat and V-shaped walls of the bottom plate, respectively, a pair of wedge-shaped friction shoes in comi plementary engagement with said walls, and a compressed resilient member seated against said shoes, said shoes being received within said housings and slidably movable in a vertical direction against said V-shaped walls and slidably movable in both vertical and horizontal directions against said fiat walls. 10. A friction device comprising a top follower having a pair of downwardly diverging friction walls, a bottom follower having a pair of upwardly diverging friction walls, certain of said walls being V-shaped and other of said walls being fiat, a pair of friction shoes each having friction surfaces in pressure engagement with the respective friction walls of said followers, compressed resilient means between said shoes for actuation thereof, all of said walls and the respective engaged surfaces being relatively movable upwardly and downwardly, and said other walls and the respective engaged surfaces being relatively movable horizontally. 11. A friction device comprising spaced followers each having opposed friction surfaces symmetrically diverging toward the other follower, friction shoes each complementally engaging surfaces of respective followers, compressed resilient means between said shoes for actuation theerof, certain of said surfaces being fiat to accommodate lateral movement of the shoes along said certain surfaces, other of said surfaces being nonplanar to prevent lateral movement of the shoes along said other surfaces. 12. A friction device comprising a top follower having a pair of downwardly symmetrically diverging friction walls, a bottom follower having a pair of upwardly symmetrically diverging friction walls, certain of said walls being curved and other of said walls being flat, a pair of friction shoes each having friction surfaces in pressure engagement with the respective friction walls of said followers, compressed resilient means between said shoes for actuation thereof, all of said walls and the respective engaged surfaces being relatively movable upwardly and downwardly, and said other walls and, the respective engaged surfaces being relatively movable horizontally. 13. A damping device comprising a top follower, a housing compartment formed on the inside of said follower, said compartment comprising a pair of transverse webs interconnected by a pair of spaced and downwardly diverging friction walls, a bottom follower, a compartment formed on the inside of said follower and comprising a pair of transverse Webs interconnected by a pair of spaced and upwardly diverging friction walls, certain of said walls being of continuous nonplanar formation and certain other of said walls being flat, a pair of friction shoes in wedge engagement with said top and bottom follower walls, compressed resilient means between said shoes, said shoes being slidably movable in both horizontal and vertical directions against certain of said friction walls. 14. A damping device comprising a top follower, a housing formed on the inside of said follower, said housing comprising a pair of transverse webs interconnected by a pair of spaced and downwardly diverging curved friction walls, a bottom follower, a housing formed on the inside of said bottom follower comprising a pair of transverse webs interconnected by a pair of spaced and upwardly diverging fiat friction walls, a pair of friction shoes in wedge engagement with said walls, and a compressed resilient member seated against said shoes, said shoes being received within said housing and snugly engaged with the transverse web of said top follower, said shoes being slidably movable in both vertical and horizontal directions against the friction walls of said bottom follower and slidably movable upwardly and downwardly against the friction walls of said top follower. 15, A damping device comprising a top follower, a housing formed on the inside of said follower, said housing comprising a pair of spaced transverse webs interconnected by a pair -of spaced and downwardly diverging friction walls, one of said walls being arcuate and the other flat, a bottom follower, a housing formed on the inside of said bottom follower comprising a pair of spaced transverse webs interconnected by a pair of spaced and upwardly diverging friction walls, one of said second mentioned walls being arcuate and the other fiat, the flat and arcuate walls of the top plate being diagonally opposed to the fiat and arcuate walls of the bottom plate, the flat wall on one plate being substantially vertically aligned with the arcuate wall on the other plate, a pair of wedge shaped friction shoes in complementary engagement with said vertically aligned walls, and a compressed resilient member seated against said shoes, said shoes being received within said housing and snugly engaged with the webs adjacent said arcuate walls and slidably movable upwardly and downwardly against said arcuate walls and slidably movable in both vertical and horizontal directions against said flat walls. References Cited in the file of this patent UNITED STATES PATENTS 1,146,772 Tatum July 13, 1915 2,110,004 OConnor Mar. 1, 1938 2,360,262 Oelkers Oct. 10, 1944 2,417,410 Gray Mar. 18, 1947 2,427,864 Lehrman et al Sept. 23, 1947

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Patent Citations (5)

    Publication numberPublication dateAssigneeTitle
    US-1146772-AJuly 13, 1915John J TatumFriction draft-gear.
    US-2110004-AMarch 01, 1938Edward P O'connorRailway car truck
    US-2360262-AOctober 10, 1944American Steel FoundriesSpring group
    US-2417410-AMarch 18, 1947Peerless Equipment CompanyDraft gear
    US-2427864-ASeptember 23, 1947American Steel FoundriesSpring group

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    Publication numberPublication dateAssigneeTitle