US3626864A

US3626864A - Fluid truck snubber

Info

Publication number: US3626864A
Application number: US801884*A
Authority: US
Inventors: Donald Wiebe
Original assignee: A Stucki Co
Current assignee: A Stucki Co
Priority date: 1968-10-23
Filing date: 1968-10-23
Publication date: 1971-12-14
Anticipated expiration: 1988-12-14

Abstract

A suspension system for railway freight cars having hydraulic energy-absorbing devices with reciprocable members effective to damp the movement of a railway car with respect to the supporting trucks therefor and the method of absorbing energy occurring during such movement.

Description

United States Patent [72] Inventor Donald Wltbe 3,150,783 9/1964 Campbell et a1 213/43 Sewlckley, Pa. 3,152,699 10/1964 Vickerman 213/8 [2]] Appl. No. 801,884 49,086 8/1865 Converse.. 267/3 [22] Filed Oct. 23, 1963 1.5 17,724 12/1924 Giuliana 293/86 [45] Patented Dec. 14, 1971 1,570,624 1/1926 Dominquez 293/71 [73} Assignee A. Stuckl Company 1,658,962 2/1928 Aikens 188/88 Pittsburgh, Pa. 1,660,526 2/1928 Richardson 308/138 Continuation-lu-part of application Ser. No. 1,702,675 2/1929 Ventura 293/86 534,220, Mar. 14, 1966, now abandoned 2,099,240 1 1/1937 Sproul 267/4 which is a continuation-impart of 2,244,501 6/ 1 941 Pierce 188/88 application Ser. No. 468,850, July 1, 1965, 2,250,134 7/1941 Pointer 280/439 now abandoned and a contlnuatlon-ln-part 2,256,868 9/1941 Perkins... 105/ 1 97 D of 579,709, Sept. 15, 1966, now 2,636,726 4/1953 Mercier 267/8 abandoned. This application Oct. 23, 1968, 2,642,008 6/ 1 95 3 Settles et al.... 105/197 D Sel'. No. 801,884 2,859,978 11/1958 Brimhall 280/136 2,914,143 11/1959 Foch! 267/34X 2,960,350 11/1960 Broughton et a1. 280/136 [5 FLUID TRUCK SNUBBER 3,005,629 10/1961 Williams 105/197 D 42 Claims, 32 D B 8 3,045,998 7/1962 Hirst 105/199 X 52 us. C1 nos/199 R, 3,231,257 H1966 105/199X 105/197 D, 105/199 C, [05/200, 188/298, 3,262,693 7/1966 l-lirst 267/3 188/317, 213/43, 213/223, 267/4, 267/34, 267/64 3,351,336 11/1967 Blake 105/199 X fi z ql/ zq y zz 2 0/ g g0u 3,464,366 9/1969 Seay 105/197 D 280/440, 308/136, 308/137, 308/138, 308/226 FOREIGN PATENTS [51 1 Int. Cl 38661125501126, 574 17 1 94 Great Britain: 5 0 50 Field 6: Search 105/164 La I99, 193, 197, 197 13,229,. 199 R, 99 C; 88/88 Assistant Examiner-Howard Beltran 88.503, 88.505, 88.506, 96.51, 96.6, 298, 317; walla 213/43, 223; 267/3, 4, 8, 34, 64, 65, 120, 122, A; 280,124 3 1:2 g gz g g ABSTRACT: A suspension system for railway freight cars hav- 308/26' l3 ing hydraulic energy-absorbing devices with reciprocable members effective to damp the movement of a railway car [56] References Cited with respect to the supporting trucks therefor and the method UNITED STATES PATENTS of absorbing energy occurring during such movement. 3,145,055 8/1964 Carter 2 67/ 34 I B & l 33 21 25 2 a5 21 2a 2 9 28 2 9 Patented Dec. 14, 1971 Y 3,626,864

15 Sheets-Sheet 1 //v l ENTOR N DONALD WIEBE Patented Dec. 14, 1971 3,625,864

15 Sheets-Sheet 2 /N|/EN7'OR DONALD WIEBE Patented Dec. 14, 1971 15 Sheets-Sheet 3 /Nl ENTOR DONALD WIEBEI Patenied Dec. 14, 1971 15 Sheets-Sheet L INVENTOR DONALD WIEBE ATTORNEY Patented Dec. 14, 1971 3,626,864

15 Sheets-Sheet 5 lllllgl! I4 7 2a Imam as f I N VEN TOR DONALD WIE BE A T TQRNE Y Patented Dec. 14, 1971 3,626,864

15 Sheets-Sheet 6 n4 P I ll5 [24 I30 I36 I35 35 I36 L39 2) 3 7 Z; I8 :34 2! I26 I I26 22 t 22 INVENTOR.

DONALD WIEBE Patented Dec. 14, 1971 3,626,864

15 Sheets-Sheet 7 Fig. I5. 282

INVENTOR. DONALD WIEBE ATTORNEY Patented Dec. 14, 1971 15 Sheets-Sheet 8 INVENTOR.

DONALD WIEBE ATTORNEY MQI I I r! I: I I I I r Patented Dec. 14, 1971 15 Sheets-Sheet 9 ATTORNEY INVENTOR- ONALD WIEBE W D J/VM m 7 6 Now mm Patented Dec. 14, 1971 3,626,864

15 Sheets-Sheet 11 1 1 1 1 1 1 I I [J g 24. INVENTOR. DONALD W/EBE Patented ec. 14, 1971 9 9 15 Sheets-Sheet 15 53 Eli/gm 32,

Patented Dec. 14, 1971 l5 Sheets-Sheet 1 5 FLUID TRUCK SNUBBER This application is a continuation'in-part of application Ser. No. 534,220 filed Mar. 14, 1966 (now abandoned) which application was a continuation-in-part of application Ser. No. 468,850 filed July I, 1965 (now abandoned) and this application is also a continuation-in-part of Ser. No. 579,709 filed Sept. 15, I966 (now abandoned).

The lateral instability of freight cars and the derailments caused thereby are well known in the art and the resonance environment that results when freight cars, including the newer types known as high center of gravity cars, traverse track with cross level differences changes are set forth in the paper entitled "The Effects of the Lateral Instability of High Center Gravity Freight Cars" presented Mar. 27, 1968 to the I968 Joint ASME-IEEE Railroad Conference on Mar. 27, 1968 in Chicago, Ill. and which has been published under the same title by the American Society of Mechanical Engineering, Journal of Engineering for Industry, Nov. I968 issue. In addition to the references in said paper the above-identified prior applications identify some of the prior art relevant to this invention.

The various objects and advantages of this invention will become more readily apparent upon consideration of the following description and drawings, in which FIG. I is a side elevational view of a railway car truck having snubber therein which is constructed, located and operable in accordance with the principles of this invention;

FIG. 2 is a cross-sectional view of the end of a bolster, the supporting spring group, and the side frame as shown in FIG.

FIG. 3 is a partial sectional view taken substantially along line 3-3 of FIG. 1;

FIG. 4 is an enlarged cross-sectional view of the snubber shown in FIG. 1;

FIG. 5 is a view similar to-FIG. 1 having a snubber of this invention located above a bolster-supporting spring group;

FIG. 6 is a view similar to FIG. 2 showing the snubber shown in FIG. 5;

FIG. 7 is an end elevational view of a portion of a railway car and truck support therefor having a snubber of this invention located therebetween;

FIG. 8 is a top plan view of one end of the truck support as shown in FIG. 7;

FIG. 9 is a side elevational view of the structure shown in FIG. 8;

FIG. 10 is an enlarged sectional view of the snubber shown in FIG. 7;

FIG. 11 is a sectional view similar to that of FIG. 10 of another embodiment of this invention;

FIG. 12 illustrates an arrangement wherein a snubber of this invention is mounted on the truck bolster;

FIG. 13 is a cross-sectional view of a modified reservoir for a snubber of this invention;

FIG. 14 is a fragmentary cross-sectional view of another snubber of this invention;

FIG. 15 is a fragmentary cross-sectional view of another snubber of this invention;

FIG. 16 is a view, partly in elevation and partly in section, of a portion of a railway car body and truck support therefore having a snubber of this invention located therebetween;

FIG. 17 is a sectional view of another embodiment of a snubber of the invention located between the car center plate and the truck bolster;

FIG. 18 is an enlarged view, in section, of the snubber of FIG. 17 when fully angularly displaced;

FIG. 19 is a view, similar to FIG. 17, of a modified form of snubber of this invention incorporated directly into a car center plate and truck bolster;

FIG. 20 is an enlarged view, in section, of still another modified form of a snubber of this invention;

FIG. 21 is a view similar to FIG. 7 of a modified application of the snubber as shown in FIG. 7;

FIG. 22 is a view similar to FIG. 21 of still another modified application of the snubber as shown in FIG. 7;

FIG. 23 is a fragmentary partially sectional end elevational view of a car body underframe and the supporting truck therefor incorporating the side frame of this invention;

FIG. 24 is a side elevational partially sectional view of the structure of FIG. 23;

FIG. 25 is a sectional view of a portion of the structure of FIG. 23 on an enlarged scale showing a snubber constructed according to the principles of this invention;

FIG. 26 is a fragmentary sectional view similar to a portion of FIG. 25 taken substantially on the line 26-26 of FIG. 27 and showing another embodiment of the principles of this invention;

FIG. 27 is a fragmentary sectional view taken substantially on line 27-27 of FIG. 26;

FIG. 28 is a view similar to FIG. 23 showing another embodiment of the principles of this invention;

FIG. 29 is a side elevational partially sectional view of the structure of FIG. 28;

FIG. 30 is a fragmentary sectional view of another embodiment of the principles of this invention;

FIG. 31 is a fragmentary sectional view of the embodiment of FIG. 30 with elements in different relative positions; and

FIG. 32 is a fragmentary sectional view of another embodiment.

As illustrated best in FIGS. 7 to 9 the conventional railway freight car comprises an elongated car body 12 supported upon four-wheel truck assemblies 14 (only one of which is shown) adjacent the ends of the car body 12. Each truck assembly has a pair of parallel axles 16 extending transversely of the body 12 with spaced journal wheels 18 being carried by each axle 16 to properly engage railroad tracks of a known gage. The outer ends of the axles 16 are suitably rotatably supported in known journal boxes 20 and each pair of adjacent boxes 20 at opposite sides of each truck assembly 14 is connected by known truck side frames 21. Each side frame 21 has a formed opening intermediate the axles I6 which provides a lower support portion 23 for supporting the lower ends of a suitable spring group 22 comprised of a plurality of vertically extending springs. A bolster 27 extends between each pair of opposed side frames 21 with the undersurface of the opposite ends thereof being supported by engagement with the upper ends of opposed spring groups 22. Longitudinally spaced portions of the body 12 adjacent the ends thereof are supported by the longitudinally spaced bolsters 27 by means of suitable center sill assemblies which illustratively comprise circular center plates 24 extending downwardly of the body 12 which are received within upwardly open cup-shaped bearings 25 rigidly carried centrally by the bolsters 27, respectively. Inasmuch as the structure of truck assemblies for railway freight cars and their structural cooperation with components of freight car bodies are well known in the art the description herein of such structures is of a general nature as a detailed description is not essential to the understanding of this invention by one skilled in the art to which it pertains.

With such known suspension the weight of the body 12 is supported by the abutting engagement of the center plates 24 with the surfaces of bearings 25 and the truck assemblies I4 are capable of rotating with respect to the center plates 24 when negotiating a curve in the track. The body 12 is thus normally supported upon a narrow area as compared to the width of the body 12 and accommodates for small differences in track profile, raising or lowering one end or the other of the bolsters 27 without severe or undue twisting the body I2. To prevent the body 12 from tilting too far in either direction, suitable known side bearing assemblies are provided such as those wherein a pair of rollers 28 is mounted on the top surfaces of the bolsters 27 at some distance on either side of the center plate 24 and wear plates (not shown) are fixed to the bottom of the body 12 above the rollers 28, respectively, with a space of one-quarter to three-eighths of an inch between the bottom surface of the wear plate and the top surface of the rollers 28. When the body 12 is tilted or rocked to one side or the other, one of the wear plates contacts a side bearing assembly or pair of rollers 28 to arrest further relative motion between the bolsters 27 and the body 12 while maintaining the ability of the truck to rotate about the center plate 24 as needed.

When a body 12 is traveling over track the normal rocking of the body 12 is readily arrested by the side bearing assemblies with perhaps slight compression of the spring groups 22 supporting that end of the bolster 27 toward which the body 12 is swaying. Due to the yielding of the spring groups 22, the body 12 rebounds from the extreme tilted position and under certain conditions will swing over to tilt in the opposite direction and strike the side bearing assembly on the other side of the truck assembly 14 to produce a series of oscillations between the extreme positions of the body 12. As is known, a resiliently mounted body has a natural period of vibration associated with its mass, the position of its center of gravity, the resilient characteristics of the mounting member and the geometry of the whole system. In many instances the energy of the first tilting motion is absorbed in the internal and external friction of the various members involved, but when a body 12 is traveling along a track the energy of the first impulse provided by the rising of a pair of wheels on one side of the truck assembly 14 will initiate a rocking motion to the body 12 and such rocking motion is often augmented by a second impulse produced by the opposite pair of wheels 18 passing over a high portion of track at or near the time of the rebound from the first oscillation. Since such augmentation may well be much greater than the energy absorbed during the first swing, the second swing may well be more violent that the first. In an extreme case, a number of impulses occurring at intervals of time almost exactly equal to the period of oscillation of the body 12 will be added together to produce extreme and dangerous rocking of the body 12.

One preferred form of this invention as presently contemplated is shown in FIGS. 1-4 wherein a snubber is located in the position of one of the springs of the prior art spring groups 22. A typical prior art arrangement of the springs in a spring group 22 is shown in FIG. 3 with the snubber 2 replacing one of the springs and comprises seven large springs 4 and nine smaller springs 6 with each of the large springs 4 having a smaller spring 6 internally coaxial therewith to provide a maximum of spring force for the space available. In such conventional spring groups 22 three of the large springs 4 are located in a slightly outwardly curved row at the extreme outer end of the bolster 27 (only two being shown) and three other large springs 4 are located in a similar slightly oppositely curved row at the portion of the bolster 27 in juxtaposition with the inner side of the side frame 21. A single large spring 4 is located between the center springs 4 of the inner and outer rows and a pair of small springs 6 are located between the ends of the inner and outer rows of springs. As shown the center spring 4 and the spring 6 encompassed thereby of the outer row of springs 4 has been replaced by a spring group snubber 2. Although one typical prior art arrangement of springs 22 has been shown other prior art spring group arrangements are modifiable to incorporate the snubbers of this invention.

Snubber 2 (FIG. 4) extends vertically in use and comprises a bottom platen 3 having a substantially flat bottom surface supported upon a central area of the bottom portion 23 of side frame 21. The upper surface of the platen 3 is substantially spherically concave on a large spherical radius and supports thereon a bottom end portion 5 of a lower member 7. Member 7 has a tubular cylinder portion 8 extending upwardly from the end 5 with the upper end thereof terminating in a ringshaped stop element having an inwardly extending stop portion 9. The bottom surface of end 5 is convexly spherical with a spherical radius substantially shorter than the radius of the upper surface of the platen 3, and cooperates with the upper surface of the platen 3 in a manner very similar to that described in my previously copending application Ser. No. 709,142 filed Feb. 28, 1968. The upper portion of cylinder 8 is encompassed by the lower portion of a compression-type helical spring 10 with the lower end of spring 10 being supported on an outwardly extending flange portion 1 1 of cylinder 8 having a suitable upwardly facing supporting surface engaged by the lower end of spring 10.

A top platen 13 having a substantially spherical concave bottom surface 15 of generally the same spherical radius as the spherical radius of platen 3 is biased into engagement with a downwardly facing outer area of the bolster 27 by the spring 10. Spring 10 has a free length such that when installed, by separating one end of the bolster 27 from the adjacent bottom portion 23 of the side frame 21 the maximum amount permitted by the interfitting of such parts, the compression of spring 10 will bias

platens

3 and 13 into firm engagement with the opposed upwardly facing surface on the bottom portion 23 and the undersurface of the end portion of the bolster 27, respectively. The outer periphery of platen 13 provides an outwardly and downwardly open notch 19 for receiving the upper end of spring 10 such that the spring 10 is retained coaxially with the central axis of the snubber 2.

Slidably received within the cylinder 8 is a formed hollow piston 302 having an upper end portion 304 which has a spherical convex upper surface of shorter radius than the bottom surface of the top platen l3 and related to that surface in the same manner as the two aforementioned spherical surfaces. End 304 is rigidly secured to a downwardly extending tubular side portion 306 which for the major axial extent thereof from the location thereof is closely telescopically received within the cylinder 8. With the snubber 2 in the collapsed position the lower end of side 306 engages an upper flat inner surface of the platen 5. The piston 302 is provided with axially spaced external

circumferential grooves

305 and 307 upwardly adjacent the lower end thereof which

grooves

305 and 307 are respectivelyv suitably dimensioned to receive suitable sealing elements such as an O-ring 308 and a metallic piston ring 310 of a type well known in the art of hydraulic cylinder construction. Piston 302 has an integral partition portion 312 extending across the interior of the piston 302 axially inward from the lower end thereof which divides the interior of the piston 302 into an upper closed chamber portion or reservoir 314 and a lower open chamber portion 316.

Hydraulic communication between the reservoir 314 and the lower chamber 316 is through a central bore or passageway 318 centrally coaxial with the piston 302 and a plurality of smaller bores or passageways 319 circumferentially spaced on a common diameter of piston 302 and radially spaced from and parallel to passageway 318.

Chambers

314 and 136 are substantially filled with a suitable hydraulic fluid and passage of fluid from the lower chamber 316 to the reservoir 314 is controlled by a ball valve 320 seated on a suitable seat at the upper end of passageway 318 which valve 320 is biased into engagement with the seat therefor by a compression-type helical spring 322 interposed between the underside of the upper end 304 and the upper surface of the valve 320 to provide a high-pressure check valve structure. Extending over and slightly beyond the bottom ends of the passageways 319 is a ring-shaped flat valve 324 which is biased lightly against the area of the partition 312 adjacent the bottom ends of the passageways 319 by a slightly compressed helical compression spring 326. Spring 326 is supported by a suitable snapring 327 and washer 328 mounted on a downward extension or center post 329 of the central portion of the partition 312 in a suitable snapring groove or by other suitable removable connections. Passageway 318 extends upwardly through the post 329.

Radially outwardly of the ring valve 324 and interposed between the bottom surface of the partition 312 and the upper surface of the bottom end 5 is a pair of springs 330 applying a moderate upwardly biasing force on the piston 302 to cause the piston 302 to be extended from the cylinder 8 whenever the cooperable bolster end moves upwardly in a direction away from the portion 23 of the side frame 21. The amount of extension of the piston 302 fromthe cylinder 8 is limited by an external circumferential shoulder 332 extending outwardly of the side 306 which is engageable with the underside of the stop 9. After shoulder 332 engages the stop 9 further separation of the bolster 27 from the bottom portion 23 causes a gap, clearance or space 334 to occur (FIG. 1) between the top member 304 and the top platen 13 since spring maintains the upper and lower platens in engagement with the opposed surfaces on the bolster 27 and the portion 23.

The vertical extent of the clearance 334 is such that the distance the spring groups 22 are compressed when supporting a loaded body 12 during travel over typical track profile which does not cause or result in severe or dangerous rocking is somewhat less than the vertical extent of the clearance 334 and the snubbers 2 are not activated during such travel. A typical clearance 334 dimension of 3/16 inch is sufficient to accommodate approximately 90 percent of all the permissible spring movements with a loaded body 12. Consequently the snubbing action of the embodiment is limited to cycles of spring movement where the motion of a loaded body 12 causes compression of a spring group 22 greater than the extent of clearance 334.

During the movement of a body 12 over railway tracks the top platens 13 move upwardly and downwardly with extension and compression of spring groups 22 and increase and decrease the vertical dimension of the clearances 334 without moving the pistons 302 within the cylinders 8 as long as the distance the spring groups 22 are axially compressed is not greater than the vertical extent of clearances 334. When either spring group 22 is axially compressed a distance greater than the clearance 334 the associated top platen 13 contacts the top member 304 of the associated piston 302 and forces the piston 302 downwardly into the cylinder 8. As the piston 302 begins to move downwardly within the cylinder 8 compression of the hydraulic fluid within the lower chamber 316 is initiated and, as the piston 302 continues its descent increases the pressure within the hydraulic fluid until a sufficient hydraulic force is effective upon the lower hydraulically effective area of valve 320 to overcome the bias of spring 322. When such hydraulic force is obtained in the lower chamber 316 the spring 322 is compressed and the valve 320 moved upwardly off the seat therefor at the upper end of passageway 318 and the pressurized hydraulic fluid flows from the lower chamber 316 through the passageway 318 into the reservoir 314. The given, specific or constant pressure of the hydraulic fluid at which the valve 320 moves upwardly is dependent upon the downward biasing force of the force of the spring 322 and the area of the valve 320 to which the hydraulic fluid is applied. At any time the pressure of the hydraulic fluid in chamber 316 falls below such constant pressure value the valve 320 is biased into engagement with the seat therefor.

Passageway 318 is preferably of a cross section to permit flow of pressurized hydraulic fluid therethrough from lower chamber 316 at a rate that the pressure of the hydraulic fluid remaining in the chamber 316 remains substantially constant during continued descent of the piston 302. Thus, this preferred embodiment is directed to a snubber for a railway car which is located in a spring group and is only operable when a given pressure is developed within a hydraulic fluid in a chamber of decreasing volume and, thereafter the hydraulic fluid within such chamber as the volume continues to decrease remains substantially at such specific or constant pressure. Accordingly, the cross-sectional area of passageway 318 is determined by the relative velocity of the piston 302 with relation to the cylinder 8 which occurs during movement of a loaded body 12 over a generally encountered or normal section of track. Further in such a constant pressure snubber the cross-sectional area of passageway 318 is of a magnitude to permit free flow of hydraulic fluid therethrough without incurring any viscous drop to any substantial degree and permit substantially all the pressure drop in the hydraulic fluid to occur in the passageway defined by the displaced valve 320. In practice a passageway 318 of 3/ 16 inch to 1/2 inch diameter has been satisfactory.

During the flow of pressurized hydraulic fluid into the reservoir 314 the passageway 318 functions as a submerged orifice and such flow causes a large portion of the energy required to pressurize the hydraulic fluid to be converted into heat. In order to obtain the desired flow of hydraulic fluid the fluid contained within the snubber 2 is of a quantity to provide a submerged orifice at the upper end of passageway 318 for all relative axial positions of the lower member 7 and the piston 302.

After the completion of any downward motion of the piston 314 and the end portion of the bolster 27 thereafter moves upwardly with respect to the top platen 13, the piston 314 thereafter moves upwardly due to the bias of springs 330. As the piston 314 moves upwardly the volume of the open chamber 316 increases and a slight decrease in pressure of the hydraulic fluid therein occurs so that passageway 318 is closed by valve 320. As the piston 314 continues to move upwardly the pressure of the hydraulic fluid within the lower chamber 316 becomes lower than the pressure of the hydraulic fluid within reservoir 314 and the pressure of the hydraulic fluid within the reservoir 314 is effective upon the top surface of the valve 324 to move the valve 324 downwardly away from the bottom ends of the passageways 319 and hydraulic fluid from the reservoir 314 flows into the lower chamber 316 to maintain the open chamber 316 full of hydraulic fluid for all relative positions of the lower member 7 and the piston 302 whereby the snubber 2 is in a position to again be operational as described upon any downward movement of the piston 302 occurring after the gap 334 has been traversed.

Snubbers 2 have a collapsed height which includes the height of the

platens

3 and 13 equal to or preferably slightly less than the collapsed height of spring groups 22 so that the spring groups become solid before the snubbers 2 are fully collapsed whereby no further forces are applied to the snubbers 2, thus preventing damage from possible overstressing.

The use of snubbers 2 as described results in snubber force being additive with the closing force being applied to the spring group 22 in which the snubber 22 is located. Although the

platens

3 and 13 are preferred either or both may be omitted in which event the end of the top member 304 engages the undersurfaces of the end portions 17 of the bolsters 27 and the bottom surfaces of the bottom ends 5 engage the upper facing surfaces of support portions 23. With such modification the springs 10 of the snubbers are of a length to hold the ends of the snubbers firmly in engagement with such surfaces throughout the greatest separation of the end portions 17 from the bottom portions 23 and the surfaces engaged are preferably provided with spherical surfaces corresponding to the spherical surfaces or

platens

3 and 13.

As indicated the typical clearance 334 of a loaded car is approximately three-sixteenths of an inch however when a car is unloaded the clearance 334 increases to about 1 1 H1 6 inches due to the unloaded condition of the spring groups 22. With such unloaded condition clearance snubbing action does not occur until the end portions 17 of the bolster 27 move a distance greater than increased clearance. Such limiting of the snubbing action to potentially damaging cycles of spring excursion is a highly desirable feature since it greatly reduces wear and heat production of the snubber of this invention as compared to continuously acting snubbers. If desired, snub bers 2 can be utilized as described without a clearance 334 and in such event a snubbing force would be obtained upon all movements of the ends of the bolsters 27 towards the support portions 23. Although a standard truck assembly 14 has been shown and described a modified truck assembly 14 having longer springs 4 and 6 in the spring groups 22 is a desired alternate structure. in such alternate structure larger snubbers 3 are utilized and larger clearances 334 are obtainable.

FIGS. 5 and 6 illustrate another preferred embodiment in which like parts have been identified by like reference numerals. ln this embodiment the spring groups 22 of the prior art described are utilized and snubbers 2 are located between the outer end portions 17 of the bolsters 27 and the upper portions 23 of the side frame 21. Bolster 27 is of any conventional structure and a known bolster 27 having a hollow rectangular end portion 17 with suitable internal bracing and external guide or retaining means is illustrated. The upper cross-extending portion of the bolster 27 at each end portion 17 is provided with an opening 336 in alignment with the central spring 4 of the spring group 22 therebelow. The upper portion 335 of the side frame 21 is of known construction such as the inverted U-shaped member shown with the opening between the downwardly extending side portions thereof being vertically aligned with the opening 336. A snubber 2 extends vertically between an inner downwardly facing surface 338 on the upper bight portion of the upper portion 335 and the inner upwardly facing surface 340 of the lower crossmember of the outer end portion 17 of the bolster 27 each each side of each truck assembly 14. As installed the upper surface of the top platens l3 engage the inner downwardly facing surfaces of the upper portions 335 and the lower surfaces of the lower platens 3 engage the inner upwardly facing surfaces of the lower crossmembers of the end portion 17. Snubbers 2 are of the structure previously described; however, snubbers 2 in this embodiment are of an overall length to function upon movement in the same manner as previously described. In order to so function the length of the snubbers 2 can vary dependent upon the distance existing between the surfaces between which the ends of the snubbers 2 operates. Such distances are known for various prior art structures of side frames 21 and bolsters 27. As before, spring has a free length such that when snubbers 2 are installed by separating the bolsters 27 from the upper portions 335, and the bolster 27 thereafter moves upwardly due to the force of the spring groups 22 and the bolster 27 is supported with the body 12 at rest, the

patens

3 and 13 are biased into firm engagement with the

surfaces

338 and 340, respectively; a clearance 334, typically of three-sixteenth inch, is provided between the upper surface of top member 304 and the lower surface of the top platen 13 which clearance 334 is sufficient to accommodate approximately 90 percent of the spring movements of a loaded railway car. The operation of the snubbers 2 located above the spring groups 22 is the same as previously described; however, the energy input to the snubbers 2 is different due to locating the snubbers 2 above the spring groups 22. In this embodiment the snubbers 2 operate in series with the spring groups 22, respectively, during the periods the spring groups 22 are extending, that is, the period any one spring group 22 is rebounding and releasing the energy stored therein during the prior period of compression thereof due to the movement of the bolster end portion 17 towards the bottom portion 23 causing compression of the spring group 22 therebetween. For the same' reasons previously stated the clearance 334 when a body 12 is fully loaded permits the spring groups 22 to extend a distance equal to that of the clearance 334 without causingthe snubbers 2 to operate to absorb the rebound energy. When the spring groups 22 move the end portions 17 of the bolster 27 upwardly a distance greater than the clearance 334 the snubbers 2 are subjected to a compression force whereby energy is absorbed as previously described. In such operation the extending spring groups 22 remain in engagement with the lower surface of the end portion 17 of the bolster 27 and the movement of the bolster 27 towards the upper cross portion 335 after the clearance 334 has been traversed causes compression of the snubbers 2.

In this embodiment the snubbers 2 result in the snubber force being applied to dissipate the rebound or extension energy of a spring group 22; that is, the snubbing force is a constant pressure force which retards the extension of a spring group 22 and which snubbing force is opposed to the extension force. Further the modifications previously mentioned regarding snubbers 2 are applicable to this embodiment. In this embodiment the increase in clearance 334 for unloaded bodies 12, as previously described, is not obtained and when bodies are unloaded the snubbers 2 are effective at all times.

Although preferred embodiments have been heretofore described the principles of this invention can also be employed in other types of snubbers or at other locations of a railway car at which snubbing action is desired. Further although the previously described embodiments have been designated as preferred embodiments it is quite possible that some of the hereinafter-described embodiments will in fact be the preferred embodiments dependent upon experience gained over periods of actual use.

F I68. 7 to 10 illustrate another type of snubber 26 of this invention. In this embodiment prior art spring groups such as spring groups 22 are utilized and the snubbers 26 are cooperable with the spaced roller bearings 28 mounted in channel sections 29 secured to the truck bolster 27 intermediate the spring groups 22 and the center plate 24, respectively, in each truck assembly 14. Snubbers 26 are secured to suitable structural supports 33 depending downwardly in alignment with the bearings 28, respectively, with the lower surface 34 of each snubber 26 constituting a bearing plate. A clearance space is preferably provided between the bearing plates and the roller bearings 28 cooperable therewith, respectively, and roller bearings 28 are adapted to roll on cam surfaces 31 formed on the lower surfaces of channel sections 29, as best shown in FIG. 9. THe clearance between the lower surfaces 34 and the rollers 28 permits the truck assembles 14 to negotiate small profile differences between the two supporting rails therefor with only minor motion influence on the body 12.

Each snubber 26 (FIG. 10) includes an upper body member 38 suitable rigidly secured to a support 33 which is normally upwardly spaced from a lower body member 40 having the lower surface 34 previously identified. The upper member 38 has a centrally located upwardly extending threaded bore 62 and the lower member 40 has a central through bore vertically aligned with the bore 62. Suitable fastening means such as a capscrew 66 extends through the central bore 64 and is threadedly engaged with the threaded bore 62 to provide means to limit the upper and

lower members

38 and 40 from separating from each other but which allows

members

38 and 40 to move together under compressive forces. A cap 68 is threaded into the outer threaded end of the bore 64 to prevent fluid from escaping from a chamber 52 through the bore 64.

Opposed surfaces of

members

38 and 40 define opposite vertically located ends of a chamber 52 therebetween with the lower member 40 having an inwardly extending annular upwardly open portion formed therein outwardly adjacent the central portion thereof through which screw 66 extends. The outer peripheral portion of chamber 52 is formed by the inner surface of an integral upwardly extending annular flange portion 48 on the outer portion of member 40. An annular ring 54 is located within chamber 52 which has a vertically extending outer surface located throughout the length thereof closely adjacent the inner surface of flange 48 to form an elongated open-ended passageway 70 therebetween. The central opening of ring 54 is located to permit the central upwardly extending portion of member 40 to travel therewithin during movement of the

members

38 and 40 towards each other as hereinafter described. As shown, the upper edge of flange 48 is generally horizontally aligned with the central portion of the lower surface of the upper member 38 when the snubber 26 is not subjected to compressive forces. Ring 54 has a downwardly facing surface of a configuration to be freely received within the annular portion of cavity 52 and an upper flat surface which is biased towards or into engagement with the lower surface of member 38 by a plurality of suitable biasing means such as springs 58. As shown, a plurality of circumferentially spaced downwardly open blind bores 56 extend up wardly in the annular ring 54, with the upper ends of springs 58 being received therein, respectively. Springs 58 extend downwardly beyond bores 56 with their lower ends engaging the upwardly facing inner surface of the annular portion of cavity 52 of lower body member 40. An O-ring 60 is desirably employed on the upper portion of ring 54 to provide a seal between the annular ring 54 and the lower surface of the upper member 38 when such members are engaged.

A fluid casing or reservoir 36 is provided which encompasses the annular opening between the upper end of flange 48 and the portion of member 38 opposed therefrom in all relative positions of the

members

38 and 40. As shown, reser-

Claims

1. A snubbing device comprising, a pair of body members having opposed portions operably movable towards and Away from each other to define a variable volume chamber therebetween, a hydraulic fluid reservoir located to maintain said chamber full of hydraulic fluid in all relative operating positions of said body members, a ring member located in said chamber intermediate said opposed portions and axially movable relative to each of said body members, said ring member upon relative movement of said body members towards each other being in substantially sealing engagement with one of said body members and cooperable with the other of said body members to define a passageway therebetween for the restricted flow of hydraulic fluid from said chamber to said reservoir.

2. A snubber as defined in claim 1 in which said ring member comprise a plurality of disks.

3. A snubbing device as defined in claim 1 in which said reservoir is formed by readily deformable estomeric material.

4. A snubbing device as specified in claim 1 wherein said passageway for restricted flow is defined by the radial outer periphery of said ring member and an adjacent encompassing portion of the other of said body members.

5. A snubbing device as specified in claim 1 additionally including passageway means communicating between said reservoir and said chamber, and valve means cooperable with said passageway means and being operable to open said passageway means when the hydraulic fluid in said chamber is above a predetermined pressure.

6. A snubbing device as specified in claim 1 wherein an upper surface of said ring member faces said one of said body members and is submerged below the operating level of the hydraulic fluid in said chamber.

7. A snubbing device as specified in claim 1 having portions of said reservoir formed integral with said body members, respectively, and movable therewith.

8. A snubbing device as specified in claim 1 additionally comprising valve means operative only during the reciprocable movement of at least one of said body members towards the other of said body members to damp relative movement of said body members by restrictive flow of hydraulic fluid from said chamber, and said valve means maintaining said restrictive flow of hydraulic fluid at substantially constant pressure.

9. A snubbing device comprising, a pair of body members having opposed portions operably movable towards and away from each other to define a variable volume chamber therebetween, a hydraulic fluid reservoir located to maintain said chamber full of hydraulic fluid in all relative operation positions of said body members, a ring member in said chamber intermediate said opposed portions and axially movable relative to each of said body members, said ring member upon relative movement of said body members towards each other being in substantially sealing engagement with one of said body members and cooperable with the other of said body members to define a passageway therebetween for the restricted flow of hydraulic fluid from said chamber to said reservoir, and means biasing said ring member towards said one of said body members.

10. A snubbing device as specified in claim 9 wherein a surface of said ring member faces said one body member and is submerged below the operating level of the hydraulic fluid in said chamber.

11. A snubbing device comprising a first member, a second member normally spaced from and reciprocably movable with respect to said first member to define a variable volume chamber therebetween, a reservoir defining a closed hydraulic system in conjunction with said chamber, said hydraulic system having a hydraulic fluid therein with an upper level thereof movable between upper and lower positions during respective reciprocable movement of said members, said first and second members having cooperable portions defining a passageway means therebetween, said passageway means having a first portion cooperable with one of said members to restrict flow of said fluid between said chamber and said reservoir upon relative movement of said members towards each other, said first portIon of said passageway being continuously located below the normal liquid level of said fluid in said system, and said passageway means having a second portion cooperable with the other of said members to provide hydraulic communication between said reservoir and said chamber substantially only upon relative movement of said members away from each other.

12. A snubbing device as specified in claim 1 wherein said second portion of said passageway means is in open hydraulic communication between said reservoir and said chamber only upon relative movement of said members away from each other.

13. A snubbing device as specified in claim 11 additionally including valve means operative only during the reciprocable movement of at least one of said members toward the other of said members to damp relative movement of said body members by restrictive flow of hydraulic fluid from said chamber, and said valve means maintaining said restrictive flow of hydraulic fluid at substantially constant pressure.

14. A snubbing device comprising: a pair of body members defining variable volume chambers therebetween; said body members being relatively movable in opposite directions; passageway means communicating between said chambers; valve means in communication with said passageway means and operative only during movement of at least one of said body members in one of said directions to damp relative movement of said body members by restrictive flow of hydraulic fluid through said passageway means and between said chambers; and said valve means and said passageway means cooperating to maintain said restrictive flow of hydraulic fluid at substantially constant operating pressure.

15. A snubbing device as specified in claim 14 wherein said chambers are upper and lower chambers and said restrictive flow of hydraulic fluid is from said lower chamber to said upper chamber.

16. A snubbing device as specified in claim 15 wherein said chambers are substantially coaxial.

17. A snubbing device as specified in claim 14 in which one of said members carries dead band valve means operable to permit relatively free flow of hydraulic fluid between said chambers during the initial relative movement in said one of said directions from a given relative position.

18. A snubbing device as specified in claim 14 wherein reservoir means for said hydraulic fluid are located laterally of said body members.

19. In a support configuration for a railway car having a section of a bolster member supported in spaced relationship to a section of a side frame member by spring means, said sections being relatively movable in opposite directions as the railway car traverses a supporting track therefor and a hydraulic snubber assembly located between oppositely facing portions of said sections, the improvement comprising: said snubber assembly including a pair of body members defining variable volume chambers therebetween and said body members being relatively movable in said opposite directions; passageway means communicating between said chambers; and said snubber assembly including valve means in communication with said passageway means and operative only during movement of at least one of said body members in one of said directions to damp said relative movement of said body members by restrictive flow of hydraulic fluid through said passageway means and between said chambers; and said valve means and said passageway means cooperating to maintain said restrictive flow of hydraulic fluid at substantially constant operating pressure.

20. In a support configuration as defined in claim 19 in which said relatively movable members are movable through a distance greater than the closed height of said spring means.

21. A support configuration as defined in claim 19 in which said snubber assembly has end portions thereof which engage said oppositely facing portions only after initial movement in said one of said directions occurs.

22. A snubbing device comprising: a pair of body members defining a variaBle volume chamber therebetween; said body members being relatively movable in opposite directions; passageway means communicating between said chamber and the exterior thereof; valve means in communication with said passageway means and operative only during movement of at least one of said body members in one of said directions to damp relative movement of said body members by restrictive flow of hydraulic fluid from said chamber through said passageway means; and said valve means and said passageway means cooperating to maintain said restrictive flow of hydraulic fluid at substantially constant operating pressure.

23. A snubbing device as specified in claim 22 wherein reservoir means for said hydraulic fluid are located laterally of said body members.

24. In a support configuration for a railway car having a section of a bolster member supported in spaced relationship to a section of a side frame member by spring means, said sections being relatively movable in opposite directions as the railway car traverses a supporting track therefor and a hydraulic snubber assembly located between oppositely facing portions of said sections, the improvement comprising: said snubber assembly including a pair of body members defining a variable volume chamber therebetween and said body members being relatively movable in said opposite directions; passageway means communicating between said chamber and the interior thereof; and said snubber assembly including valve means in communication with said passageway means and operative only during movement of at least one of said body members in one of said directions to damp said relative movement of said body members by restrictive flow of hydraulic fluid from said chamber through said passageway means; and said valve means and said passageway means cooperating to maintain said restrictive flow of hydraulic fluid of substantially constant operating pressure.

25. In a support configuration as defined in claim 24 in which said relatively movable body members are movable through a distance greater than the closed height of said spring means.

26. A snubbing device comprising, a body member having an elongated bore therein, a piston member axially reciprocal within said bore and defining variable volume chamber portions within said body member adjacent opposite axial ends thereof, said body member having hydraulic fluid within the bore thereof, dead band valve means in at least one of said members connecting said chamber portions to maintain full of hydraulic fluid the one of said chamber portions which increases in volume upon axial movement in one direction of said body member from a given relative position with respect to said piston member, means in at least one of said members operable to restrict flow of pressurized hydraulic fluid between said chamber portions upon movement of said members in a direction opposite said one direction occurring immediately subsequent to each movement in said one direction, and said dead band valve means being operable to maintain said one chamber portion full of hydraulic fluid by relatively free flow of hydraulic fluid between said chamber portions upon axial movement of said piston member in said opposite direction without having any substantial pressurization of said hydraulic fluid in said one chamber portion and said dead band valve means being initially responsive to hydraulic pressure in said one chamber portion to maintain said relatively free flow for an initial period and being further responsive to discontinue said relatively free flow subsequent to said initial period.

27. A snubbing device as set forth in claim 26 in which said dead band valve means is at least in part open-sided grooves extending between said chamber portions and axially beyond said piston member when said piston member is in said given relative position.

28. A snubbing device as set forth in claim 27 in which said grooves have a decreasing cross-sectional area along the length thereof in said one direction.

29. A snubbing device as set forth in claim 26 in which said dead band valve means has lost motion with respect to movement of said piston member in said opposite direction.

30. In a side bearing assembly for a railroad car wherein a side bearing means cooperates with a bearing plate means to limit relative rocking movement between a car truck member and a car body member, the improvement which comprises, a hydraulic damping device supported by one of said members and supporting one of said means, the other of said members supporting the other of said means, and said damping device including means maintaining a normal clearance between said bearing plate means and said side bearing means.

31. In a railway truck assembly of the type in which a laterally extending bolster pivotally supports the underside of a car body and wherein a side bearing is mounted on the truck bolster and arranged to contact a bearing plate, the improvement comprising, a hydraulic damping device interposed between said bearing plate and said body and supported with respect to said body and arranged to cushion the impact between said side bearings and said bearing plate as said car body sways, and said damping device including means maintaining a normally separable relationship between said bearing plate and said bearing.

32. In a railway truck assembly of the type in which a laterally extending bolster pivotally supports the underside of a car body and wherein a bearing plate is mounted on the car body and arranged to contact a side bearing, the improvement comprising, a hydraulic damping device interposed between said side bearing and said truck bolster and supported with respect to said truck bolster and arranged to cushion the impact between said side bearing and said bearing plate as said car body sways, and said damping device including means maintaining a normally separable relationship between said bearing plate and said bearing.

33. In a railway truck assembly of the type in which a laterally extending bolster member pivotally supports the underside of a car body member and wherein a side bearing means cooperates with a bearing plate means to limit relative rocking movement between said car body member and said bolster member, the improvement comprising, a hydraulic damping device supported by one of said members and supporting one of said means, the other of said members supporting the other of said means, said damping device being arranged to cushion the impact between said side bearing means and said bearing plate means as said car sways and said damping device including means maintaining a normally separable relationship between said bearing plate means and said bearing means.

34. In a railway truck assembly, a laterally extending bolster provided with a central bearing surface, a laterally extending saddle member overlying and spaced above said bolster and having a downwardly depending central bearing surface adapted to engage the bearing surface on said bolster, and upper bearing surface on the saddle member for supporting the downwardly depending center plate on a car body, the saddle member being adapted to rock from side to side on the central bearing surface of the bolster as the car body above it rocks from side to side, a pair of compressible and expandable fluid-damping devices carried beneath said bolster on opposite sides of said central bearing surface, and means connecting the saddle member to the damping devices such that when one damping device compresses the other expands and vice versa.

35. The truck assembly of claim 34 wherein each damping device is operatively connected to an end of the saddle member through a reciprocable column which extends through said bolster.

36. The truck assembly of claim 33 wherein the weight of the car body is normally carried by the damping devices with the damping devices compressed, and wherein the saddle member normally does not rest on the central bearing surface of the bolster.

37. The truck assembly of claim 34 wheRein the damping devices are carried on bearing plates depending downwardly from said saddle member and movable therewith as a unit, the damping devices being sandwiched between the bearing plates and the bolster such that when the saddle member rocks to one side, only one damping device will be compressed while the other expands and vice versa.

38. The truck assembly of claim 37 wherein the downwardly depending bearing surface on the saddle member normally rests on said central bearing surface such that the weight of the car body is normally carried by said truck.

39. The truck assembly of claim 34 and including side bearings carried on opposite ends of said saddle member, and wear plates on said car body adapted to engage the side bearings as the car body rocks from side to side, the wear plates being normally spaced from the side bearings when the car body is not rocking.

40. In a railway vehicle, in combination, a car body having a center plate thereon, a truck having a bolster for pivotally supporting said center plate, a hydraulic damping device interposed between said center plate and said bolster for dissipating energy by restricted flow of hydraulic fluid through a passageway, said damping device comprising upper and lower relatively movable members defining a fluid cavity of variable volume therebetween and said passageway upon at least a portion of the relative movement between said members being of a variable volume.

41. The combination of claim 40 wherein said upper and lower members form integral parts of said center plate and said truck bolster, respectively.

42. The combination of claim 40 including a plurality of stacked washers disposed in said fluid cavity between said upper and lower members.