US3464366A

US3464366A - Hydraulically dampened railway truck bolster

Info

Publication number: US3464366A
Application number: US582970A
Authority: US
Inventors: Orum E Seay
Original assignee: Halliburton Co
Current assignee: Halliburton Co
Priority date: 1966-09-29
Filing date: 1966-09-29
Publication date: 1969-09-02
Anticipated expiration: 1986-09-02

Description

HYDRAULIGALLY DAMPENED RAILWAY TRUCK BOLSTER Filed Sept. 29, 1966 O. E. SEAY 4 Sheets-Sheet 1 Nut E2 QHEw Q SHHONI HAVHl X3081 01 W3 E2 1 Qmmmm Q INVENTOR ORUM E. SEAY ATTORNEYS SBHONI IE/W81 SNIHdS Sept. 2, 1969 3,464,366

HYDRAULICALLY DAMPENED RAILWAY TRUCK BOLSTER Filed Sept. 29, 1966 O. E. SEAY 4 Sheets-Sheet 2 INVENTOR ORUM E SEAY ATTORNEY o. E. SEAY 3,464,366

HYDRAULICALLY DAMPENED RAILWAY TRUCK BOLSTER Sept. 2, 1969 4 Sheets-Sheet 5 Filed Sept. 29, 1966 INVENTOR ORUM E. SEAY ATTORNEY Sept. 2, 1969 o. E. SEAY 3,

HYDRAULICALLY DAMPENED RAILWAY TRUCK BOLSTER Filed Sept. 29, 1966 4 Sheets-Sheet 4 INVENTOR ORUM E.SEAY

ATTORNEY United States Patent O 3,464,366 HYDRAULICALLY DAMPENED RAILWAY TRUCK BOLSTER I Orum E. Seay, Duncan, Okla, assignor to Halliburton Company, Duncan, Okla, a corporation of Delaware Filed Sept. 29, 1966, Ser. No. 582,970 Int. Cl. B61f 5/06, 5/12 US. Cl. 105-197 5 Claims ABSTRACT OF THE DISCLOSURE General background of invention This invention relates to a system for stabilizing railway cars against lateral sway. In particular, it relates to such a system employing a unique disposition of hydraulic shock absorbing units between the truck and bolsters of railway cars and to the novel structure of the shock absorber unit itself.

In recent years, manufacturers of railway cars have produced cars having a greater length and height than those earlier utilized. These changes in size of railway cars have tended to raise their center of gravity and increase their tendency to sway. Such sway characteristics are troublesome in that they often induce suflicient car movement to enable the wheels of a railway car to leave the track and thereby cause train derailment.

Of particular concern has been the propensity for railway cars to undergo maximum sway at the relatively low operating speeds employed in railway switching and loading yards. At such low speeds, it has been found that many railway cars, provided with conventional spring clusters between its trucks and bolsters, reach a peak of sway movement. It is generally believed that this maximum sway condition results when a railway car undergoes movement conforming to its nautral frequency of motion, as induced by the relationship between car velocity and track irregularities.

Where the peak, railway car sway condition occurs at a sustained operating speed, the sway problem becomes so pronounced as to often result in car derailment. However, where the peak sway condition occurs as a portion of the normal acceleration cycle, the period of maximum sway is transitory and far less likely to induce car derailment or serious sway conditions. However, as will be readily apparent, even where the maximum sway condition is transitory or short lived, it is desirable to minimize car movements.

To some degree excessive railway car sway which is encountered in operation is a direct consequence of the conventional structural arrangement employed to resiliently support railway cars.

In a conventional freight car suspension arrangement, each end of the car is supported by a truck and bolster assembly. The truck carries the railway car wheels while the bolster is pivotally mounted to the underside of the railway car body. Coil spring groupings at each end of the truck are interposed between the underside of the bolster and an upwardly facing portion on one side of the truck.

In this way, the railway car bolster serves as a cross beam serving to resiliently transfer the weight of the rail- Patented Sept. 2, 1969 way car to the railway car truck. However, the conventional pivot connection between the railway car and its bolster is such as to allow some limited pivotable movement of the car relative to the bolster. Thus the car body can undergo some limited swaying movement which is not controlled by the springs supporting the bolster. Thus excessive spring movement will often tend to induce free movement of the railway car body relative to the bolster which is not adequately controlled by the bolster springs and which may be of a sufiicient amplitude to induce derailment.

Of additional concern is the normal lateral freedom of movement of a bolster relative to its associated truck.

though limited in extent, this movement is suflicient to impose severe lateral force on the suspension system.

A variety of hydraulic shock absorbing systems have been proposed for utilization in railway car stabilizing systems in an eifort to minimize car movements. However, these shock absorbing arrangements have required special mounting connections so as to complicate their installation in present railway equipment.

It also must not be overlooked that a basic problem involved in stabilizing railway cars entails the severity of forces and dynamic loading variations which are imposed on their suspension components. Obviously a railway car carrying a load on the order of a hundred tons generates forces which are exceedingly difficult to accommodate. For this reason, shock asborbing devices for use in railway cars must be characterized by unusual structural ruggedness.

Cbjects and summary of invention Particularly with respect to the new railway cars which are vulnerable to excessive sway phenomena it is an object of the present invention to provide a railway car movement stabilizing system and shock absorbing device which substantially reduce the degree of car sway and reduce or eliminate car derailment tendencies.

It is a further object of the invention to provide such an improved stabilizing system and device which reduce the extent of axially oscillating movement of railway car springs so as to reduce the amplitude of railway car body movement relative to the trucks of the railway car, i.e., relative to the track on which the car is traveling.

It is also an object of the invention to increase the speed at which maximum railway car sway conditions occur in response to track conditions to a speed above that normally employed in switching and loading yards.

It is also an object of the invention to provide a railway car shock absorber arrangement disposed between the bolster and truck of a railway car and which does not require special mounting arrangements to accommodate rotary movement of the truck relative to the car.

It is a related object of the invention to provide a shock absorber disposed between a railway car truck and bolster which is disconnected with either of these car components.

A further object of the invention is to provide an improved mounting arrangement for a railway car shock absorber wherein the problems associated with lateral car body movement relative to the shock absorber are minimized.

Yet another object of the invention is to provide a railway car shock absorbing structure which is continuously in precompressed engagement with railway car truck and bolster portions and which is nested within the conventional coil spring bolster mounting arrangement.

It is also an object of the invention to provide an improved railway car, hydraulic shock absorber including an arrangement for effectively stabilizing the movement of a piston of the shock absorber within an associated cylinder.

Yet another object of the invention is to provide an improved railway car, hydraulic shock absorber including air compression chambers which aid in restoring the piston and cylinder components to their normal positions, after they have been converged.

It is also an object of the invention to provide such 'an improved railway car shock absorbing structure including a unique passage arrangement which serves to prevent hydraulic fluid from being transferred into air compression chambers of the shock absorber body,

In order to accomplish some of the principal objects heretofore noted, there is presented through this invention a basic railway car stabilizing system comprising shock absorbing means having mutually and yieldably convergeable ends. Means provide rolling and sliding contact between one end of this shock absorbing means and one portion of a railway car while other means provide rolling and sliding contact between the other end of the shock absorbing means and another portion of the railway car.

A particularly advantageous embodiment of the invention involves this basic system wherein the shock absorbing means is disposed in a pocket defined by a plurality of axially displaced, coil spring units.

Another particularly advantageous embodiment of the invention involves the basic system including precompressed resilient means which maintain the shock absorbing means in continuous, resiliently biased, compressive engagement with relatively movable portions of the railway car suspension system.

Optimum system advantages are derived where the shock absorbing means is nested between spaced coil springs and disposed in precompressed, resiliently biasing engagement with railway car portions, with opposite ends of the shock absorbing means each being in rolling and sliding engagement with a railway car portion. In this optimum embodiment of the invention, the shock absorbing means is preferably disposed in engagement with an under portion of an end of a railway car bolster and an upwardly facing portion of a railway car truck, with such a shock absorbing mounting arrangement being provided between each end of each bolster of the railway car and its associated truck portion.

A further and independently significant facet of the invention pertains to a shock absorbing structure which is characterized by a piston stabilizing pin which projects longitudinally of piston means. A longitudinally extending, stabilizing passage is formed in the piston means and telescopingly receives the stabilizing pin. In this combination, the stabilizing pin is disposed in slidable and stabilizing engagement with the stabilizing passage continuously throughout the movement of the piston means.

In a preferred and particularly advantageous form of this shock absorber structure, passage means are carried by the piston means which provide fluid communication between the low pressure end of the piston means and the interface between the stabilizing passage and the stabilizing pin.

Uniquely important advantages are derived from the basic structure of the improved shock absorber when it includes a first wall defining a spherical segment facing outwardly of the shock absorber and a second wall defining a spherical segment facing outwardly of the shock absorber and a second wall defining a spherical segment facing outwardly of the shock absorber and away from the first wall.

Drawings In describing the invention reference will be made to a preferred embodiment as illustrated in the appended drawings.

In the drawings:

FIGURE 1 graphically illustrates performance curves comparing the maximum spring travel characteristics of a conventional railway car suspension system and the improved suspension system of the present invention;

FIGURE 2 graphically illustrates performance curves comparing the degree of maximum, railway car body to truck, movement for standard railway cars and railway cars including the improved stabilizing system of the present invention;

FIGURE 3 is a fragmentary, schematic view of an end of a railway car illustrating structural relations between a shock absorber, coil springs, railway car truck, and railway car bolster as disposed in accordance with the invention;

FIGURE 4 provides a fragmentary transverse sectional view through the shock absorbing arrangement of the FIGURE 3 stabilizing system;

FIGURE 5 is a fragmentary sectional view of the FIGURE 3 assembly, looking downwardly on the hydraulic shock absorber and its nesting pocket as defined by a plurality of axially displaced, coil springs;

FIGURE 6 is an enlarged, sectioned elevational view of the shock absorber employed in the FIGURE 3 assembly;

FIGURE 7 is a transverse sectional view of the FIG- URE 6 shock absorber as viewed along the section lines 7-7 of FIGURE 6;

FIGURE 8 is an enlarged sectional view of a check valve portion of the FIGURE 6 shock absorber as viewed along the section line 88 of FIGURE 7; and

FIGURE 9 is an enlarged sectional view of a restricted passage defining metering orifice included in the piston component of the FIGURE 6 assembly, as viewed along the section line 99 of FIGURE 7.

Overall stabilizing system FIGURES 3, 4 and 5 illustrate a typical freight car 1 which has been modified to include the stabilizing system of the present invention.

Railway car 1, in a conventional fashion, includes a car body 2, a railway truck 3, a bolster 4, a pivot bearing 5, and spring and shock absorbing suspension means 6.

Truck 3 is conventional and supports four wheels 7. On each side of the truck two wheels are aligned in engagement with a rail "8 as shown in FIGURE 3. Bolster 4 is connected by the pivot bearing 5 to the underside of railway car 1. Pivot bearing 5, consistent with the usual degree of tolerances employed in fabricating railway cars, enables car body 2 to undergo limited swaying or pivoting movement transversely of the longitudinal median plane of the car. Thus, bolster 4, .on each end of its top side, may carry a roller bearing 9 which may be spaced slightly beneath the underside of the car body 1. When the car body 2 rocks or sways laterally on the pivot bearing 5 relative to the bolster 4, its underside portion 2A will engage one of the roller bearings 9 so as to limit this rocking movement. The roller bearings 9 on each side of the bolster 4 serve to facilitate rotational movement of the bolster 4 about the generally vertical pivot axis of pivot bearing 5.

Bolster 4, at each end 10, is mounted for generally vertically guided, sliding movement in a truck aperture 11. Between the underside 10A of each end 10 of the bolster 4 and an upwardly facing base 12 at the lower end of the truck recess 11 is interposed the coil spring and hydraulic shock absorber assembly 6. As will be understood, this assembly is interposed between each end of each bolster of the railway car and its associated truck portion. Thus the car 1 is provided with four such assemblies 6, two carried by a truck at one end of the car and two carried by the truck at the other car end.

Each assembly 6 may comprise four coil springs 13 mounted in generally horizontal alignment with their axes being mutually parallel and parallel to the pivot axis of the pivot bearing 5. These four coil springs 13 have their longitudinal axes horizontally displaced so as to define a central pocket 14. Coil springs 13 may be mounted between upper and

lower plates

15 and 16 in a conventional fashion in a manner generally consistent with the coil spring and mounting plate arrangement featured on page 879 of the 1966 Car and Locomotive Cyclopedia, published by Simmons-Boardman Publishing Corporation of New York. As will be understood, many conventional suspension units employ more than four coil springs.

With this mounting arrangement, the lower plate 16, in essence, functions as an upwardly facing, planar wall portion of the truck 3, while upper plate 15 functions as a downwardly facing planar wall portion of the bolster 4. The manner in which the coil springs 13 and their associated mounting

plates

15 and 16 are secured between the truck aperture base 12 and bolster end is conventional in character and is illustrated, for example, on page 882 of the 1966 Car and Locomotive Cyclopedia.

As will be appreciated, the coil springs 13 may be installed without the associated mounting plates so as to directly engage the underside 10A of the bolster 10 and the base 12 of the truck recess 11 in the manner generally illustrated on page 818 of the 1966 Car and Locomotive Cyclopedia.

Mounted in the pocket 14, which is more or less peripherally defined by the coil springs 13, is a hydraulic, shock absorbing device 17. The hydraulic shock absorbing device includes an upper disposed, piston portion 18 which is telescopingly received within a lower disposed, cylinder portion 19. Piston and

cylinder portions

18 and 19 are mounted in the pocket 14 with their axes of telescoping movement extending generally vertically, i.e., generally longitudinally of the pocket 14. The piston portion 18 carries an upper end wall 20. End wall 20 has an upwardly and axially facing face 21 in the form of a spherical segment disposed in rolling and tangential sliding engagement with the planar wall portion of the truck 4. Cylinder 19 carries a lower end wall 22 of the shock absorber 17. End wall 22 includes a downwardly and axially facing spherical segment face 23 which is disposed in rolling and tangential sliding engagement with the upwardly facing planar wall portion 16 of the truck 3.

Preferably, the width, i.e., diameter, of each unit 17 corresponds substantially to the width or diameter of the coil springs 13. This facilitates the fabrication of an assembly 6 by merely replacing the center or fifth spring of a five-spring shock absorbing unit, as shown on page 879 of the 1966 Car and Locomotive Cyclopedia, with the shock absorber 17 of the present invention.

The width of the horizontal spaces between adjacent coil springs 13 is less than the width of the shock absorber 17. Thus the shock absorber 17 is prevented by the coil springs from moving laterally out of the pocket 14. As will be appreciated, the pocket 14, in order to restrain the hydraulic shock absorber 17 against lateral movement, requires a plurality of at least three, pocket periphery defining, coil springs 13. However, it should be here noted that the invention may be practiced with a shock absorber unit 17 being used to replace any of the springs 13. Where the unit 17 replaces an outside spring 13, it will be retained in place by conventional spring retaining structures such as the flanges of mounting plates illustrated on page 879 of the 1966 Car and Locomotive Cyclopedia.

The shock absorber 17 is disconnected with either the bolster 4 or the truck 3, being disposed only in rolling and tangential sliding engagement with these car components. A coaxial and peripherally disposed, precornpressed coil spring 24 serves to bias the

spherical segments

21 and 23 into resiliently compressive engagement with the

wall portions

15 and 16 respectively. Thus, as illustrated, coil spring 24 urges the shock absorber end walls and 22 mutually outwardly and maintains these end walls in mutually and yieldably convergeable relation.

In this fashion, each of the four shock absorbers 17 associated with the car 1 exerts a resilient lifting force against the underside of each end of each of the two bolsters 4 associated with the car 1. When a bolster 4 undergoes lateral movement relative to the truck 3, as permitted by the conventional loose, sliding mounting of the bolster end 10 in the truck recess 11, minimized horizontal thrust is imposed on the shock absorber 17 owing to the rolling and tangential, sliding contact between the upper and lower ends of the shock absorber 17 and the bolster and truck respectively. The generally point-like contact between the spherical segments enables stress relieving sliding movement to occur between the segments and the planar wall portions which they contact. The rolling contact between the segments and planar wall portions enables each shock absorber to pivot in response to the imposition of laterally directed force. This pivoting prevents the piston of the shock absorber from being jammed laterally against its cylinder so as to impede its downward movement. Excessive pivoting and/or sliding of each shock absorber 17 is prevented by the restraining influence of the inner, pocket defining, portions of the coil springs 13.

Structure and operation of shock absorber FIGURES 6 through 9 illustrate structural details of the shock absorber 17.

As previously noted, shock absorber 17 comprises a piston component 18 and a cylinder component 19.

Piston component 18 includes a generally tubular piston rod 25 having a closed upper end 26, an open lower end 27 and an annular piston head 28. Piston rod 26 is cylindrical in character so as to have a cylindrical outer surface 29.

Cylinder 19 includes a cylindrical wall 30 providing an inner wall 31 having a circular cross-section which slidably and sealing engages the outer circularly and matingly cross-sectioned periphery 32 of the annular piston 28. Annular piston 28 may carry an elastomeric or metallic piston ring 33 to positively insure slidable and sealing engagement between the piston periphery 32 and the cylinder wall 31.

Cylinder 19 has a closed lower end defined by lower end wall 22 of the shock absorber 17. As illustrated in FIGURE 6, end wall 22 may be threadably connected to cylindrical wall 30 of cylinder 19 so as to provide the closed lower end of the cylinder. As previously noted, lower end wall 22 includes a spherical segment surface 23 having a radius which is coaxial with the central axis of the cylinder wall 30 of the cylinder 19 and the piston 18.

A stabilizing pin 34 of generally uniform circular crosssection projects axially upwardly from the end Wall 22 toward the piston 18.

Piston rod 25 includes an inner surface 35 having a generally axially uniform, circular, cross-sectional configuration. Surface 3-5 defines a central, coaxial, and lo-ngitudinally extending passage 36 having an open lower end and a closed upper end.

Passage 36 continuously, telescopingly and slidably receives the upwardly projecting pin 34. Sealing and slidable engagement between pin 34 and the passage 36 may be promoted by an annular gasket 37 carried in an annular recess 38 on the upper end of the pin 34. Wall 35 of passage 36 is disposed in slidable, mating engagement with the outer periphery 39 of the pin 34 so as to positively stabilize the piston head 28 for axially centered, sliding movement within the cylinder 19. Thus, skewing of the piston 18 relative to the cylinder 19 is elfectively prevented at all times.

Piston head 28 includes at least one longitudinally extending flow impeding or flow restricting passage 40. A replaceable flow metering orifice 4 1 may be press-fitted or threaded into the passage 40 as generally shown in FIGURE 9. Passage 40 provides fluid communication between the high pressure end 42 of the piston head 28 and the low pressure end 43 of this piston. As shown in FIGURE 6, high pressure end 42 is disposed in engagement with and faces a body 44 of hydraulic fluid such as oil, while low pressure end 43 faces an at least partially unoccupied cavity 45 designed to receive fluid which passes through the restricted passage 40 from the fluid body 44.

The upper end of cavity 45 may be closed by an annular rim 46 projecting radially inwardly from the upper end of the wall 30. As shown in FIGURE 6, rim 46 may be threadably secured to the wall 30 and includes a cen tral, generally cylindrical, aperture defining surface 47 disposed in slidable and sealing engagement with the outer periphery 39 of the piston rod 25. Cylindrical surface 47 may include an annular recess 48 in which is inserted a conventional annular gasket 49 to promote slidable and sealing engagement between the rim 46 and the piston rod 25.

As will be appreciated, the passage 40 is designed to impede converging movement of the piston head 28 into the cylinder 19, i.e., downward movement of the piston head 28 as shown in FIGURE 6. This impeded movement serves to absorb compressive energy imposed on the upper end of the piston 18 by movement of the railway car body and its associated bolster 4.

Rapid return or upward movement of the piston head 28 is facilitated by check valve means 50 carried by the piston head 28.

Check valve means 50 comprises an annular valving plate 51 supported on the under or high pressure end of the piston 28. Valving plate 51 is biased upwardly into mating engagement with a radially extending valve seat 52 by a plurality of spring mechanisms 53.

Each spring mechanism 53, as shown in FIGURE 8, includes a bolt-like member 54 having a lower head 55 secured to the plate 51 and a shank 56 which passes upwardly through a piston head passage 57 to terminate in an enlarged upper end 58. Upper end 58 may be defined by a conventional nut threadably secured to the shank 56. A coil spring 59 encircles the shank 56 and at its upper end, engages the underside of the nut 58 and at its lower end, an annular seat 60 formed in the passage 57.

One or more check Valving passages 61, as shown in FIGURES 6- and 7, extend longitudinally of and through the piston head 28 so as to provide fluid communication between the high and low pressure ends of the piston head. When valve plate 51 is in its upwardly spring-biased position shown in FIGURE 6, closing the lower end of the passages 61, an upward flow of fluid from the body 44 through the passages 61 is prevented or at least effectively minimized. Thus, on the downward stroke of the piston head 28, fluid flow is governed by the flow restricting orifice 41. As shown in FIGURE 9, plate 51 includes an aperture 51A providing continuous fluid communication between passage 40 and fluid body 44.

On the upward or return stroke of the piston head 28, fluid which has been transferred into the cavity 45 may return rapidly to the passage 44 by flowing downwardly through the passages 61 and moving the plate 51 out of valving engagement with the radial face 52 by overcoming the biasing eflect of the coil springs 53. This, of course, enables the piston head 28 to restore itself in a rapid fashion.

The restoring of the piston head 28 is also facilitated by a pair of coaxial air compression chambers formed as unitary components of the shock absorber 17.

One such air compression chamber 62 is defined by the piston rod 25 and the stabilizing pin 34. Thus, compression chamber 62 comprises the upper end of the stabilizing pin receiving passage or stabilizing passage 36 defined by the interior of the piston rod 25. On the downward or compression stroke of the piston 18, air within the chamber 62 is compressed and the energy of this compressed air facilitates the restoration of the piston to its upper level.

The other air compression chamber of the apparatus comprises an annular chamber 63 which encircles the piston rod 25 and is disposed axially between the cylinder rim wall 46 and the spherical Segment defining, end wall '20.

As illustrated, wall 20 may be threadably connected to the upper end of the stem 25. A cylindrical shroud 64 is carried by the wall 20 and projects axially downwardly into slidable and sealing engagement with the outer cylindrical periphery 65 of the cylinder 19. Cylinder 19, on its outer periphery and in an annular groove 66, may carry an annular gasket 67 to promote sealing and sliding engagement between the shroud 64 and the cylinder periphery 65. Thus, on the compression or downward stroke of the piston 18, air within the compression chamber 63 is compressed and the energy of this compressed air also serves to facilitate the restoration of the piston 18 to its uppermost location.

As will be appreciated, it is undesirable that fluid within the hydraulic body 44 migrate into the

air chambers

62 or 63. The likelihood of such migration occurring is most acute with respect to the central air chamber 62.

To avoid the likelihood of migration of hydraulic fluid into the chamber 62 occurring, a unique high pressure tfluid, scavenging system is incorporated between the piston stabilizing pin 34 and the piston head 28. This scavenging system comprises an annular and radially outwardly extending recess 68 formed in the surface 35 radially adjacent the piston head 28. A passage 69' extends radially from each of the check valve passages 61 to the annular recess 68. The annular recess 68 and the radial passages 69 provide fluid communication between the lower pressure chamber 45, and the interface between the piston head 28 into stabilizing pin 34. Thus, fluid from the high pressure hydraulic body 44 which migrates between the mating faces of the piston head 28 and the stabilizing pin 34 will be transferred through the recess 68 and

passages

69 and 61 to the low pressure oil chamber 4-5, rather than to the air chamber 62.

As previously described, and as illustrated in greater detail in FIGURE 6, the lower annular surface 70 of the wall 20 outside of the shroud 64 and the upper annular surface 71 of the end wall 22 outside of the cylinder wall 19 are engaged by upper and lower ends respectively of a coil spring 24. Coil spring 24 tends to restore the piston 18 to its upper position shown in FIGURE 6 after the piston component 18 has been converged with the cylinder component 19, i.e., moved downwardly.

The shock absorbing assembly 17 is installed with the spring 24 compressed, i.e., the wall means 15 of the bolster 4 depresses the upper end 21 of the piston component 18 sufliciently to precompress the spring 24 so that the spherical segment surfaces 21 and 23 are maintamed in precompressed, tangential engagement with the

wall portions

15 and 16 respectively.

The rolling and sliding engagement between each end of the shock absorber 17 and a portion of the railway car, coupled with the continuously pin stabilized piston, assures a uniquely effective operation of the shock absorber 17.

Lateral thrust forces imposed by the railway car body 2, through the bolster 4, to the shock absorber 17, induce rolling movement of the shock absorber 17, rather than tending to skew or twist the piston head 28 within the cylinder wall 30. Any such skewing tendency as might be present is effectively offset by the piston movement stabilizing pin 34. Rapid restoration of the shock absorber, subsequent to a compression stroke, is facilitated by the coil spring 24 operating in conjunction with the

air compression chambers

62 and 63.

The continuously eflective character of the air compression chamber 62 is assured by the scavenging system defined by the recess 68 and the passage means 69 and 61. This scavenging system, of course, also prevents un desired loss of hydraulic fluid or oil from the main oil body 44.

The continuously effective compressive engagement of each of the four shock absorbers 17 with a bolster portion of the railway car 1 insures that movement of each end of each bolster of the railway car is continuously dampened without interfering with pivotable movement of the bolster 4 about its pivot mount 5.

Improvement in railway car stabilization obtained through the invention FIGURES l and 2 graphically compare railway car stabilization as achieved by conventional spring suspension systems and as achieved with a hydraulic shock absorber structure and shock absorber disposition in accordance with the present invention.

Curves A and B of FIGURE 1 depict the maximum changes in axial length of the coil springs 13 that occur in standard railway cars lacking the shock absorber structure and shock absorber mounting of the present invention.

These tests were performed on curved track sections with curve A depicting maximum movement of the coil springs located on the ends of bolsters disposed on the outside of the curved track. Curve B depicts the maximum movement of coil springs in engagement with bolsters on the inside track of the curve.

Curves C and D depict the maximum extent of axially oscillating movement of coil springs when the car suspension system has been modified by the incorporation of the shock absorber structure and mounting arrangement previously described. Curve C graphically illustrates maximum changes in axial dimension of coil springs in engagement with bolsters on the outer rail side of the track. Curve D depicts maximum axial spring movement for springs engaging bolsters on the inner rail side of the curve.

As will be apparent by reference to the curves of FIG- URE l, with a conventional suspension system, maximum spring travel during the test was measured to be of the order of about 2.9 inches. Where the suspension system was modified by the addition of the shock absorber assembly previously described, this spring travel was reduced to about 1.2 inches.

FIGURE 2 graphically illustrates comparisons of the maximum relative movement which occurs between a railway car body and one of its associated trucks with respect to standard railway car suspension systems and suspension systems modified by the incorporation of shock absorber arrangement of this invention.

Oirves E and F of FIGURE 2 were derived from the operation of railway cars having standard suspension systems and illustrate maximum relative movement between car bodies and car trucks. This movement is the general degree of relative movement between car body and car truck which occurs in the area X of FIGURE 4. Curve E depicts this movement which occurs on the railway car on the outer rail side of a track, while curve F depicts the movement which occurs on the inner rail side of a track.

Curves G and H depict the degree of maximum movement of a railway car body relative to a railway car truck where the car has been provided with the shock absorber structure and mounting arrangement of this invention. Curve G depicts maximum car to truck movement on the outer rail side of a curved track, while curve H depicts maximum car to truck movement on the inner side of a rail track.

As FIGURE 2 illustrates, with a conventional car suspension system, maximum car to truck movement, i.e., lateral sway, was on the order of 5.6 inches. Where the suspension system was modified by the structure and mounting arrangement of the shock absorber assemblies of the present invention, this sway movement was reduced in half, i.e., to about 2.8 inches.

This reduction in sway of car movement significantly minimizes the chances of car derailment. Indeed, during the test which produced the results reflected in the charts of FIGURES l and 2, wheel lifting on cars provided with the shock absorber system of this invention was not observed. However, wheel lifting with the standard car suspension systems was observed at several points.

It is also significant to note that with cars modified by the addition of the shock absorbing system of the present invention, the speed at which maximum sway occurs was raised from about sixteen miles per hour to about twenty miles per hour. This shift of the critical sway speed is significant in that most railway cars operate in railway yards at speeds often in the vicinity of fifteen or sixteen miles per hour. Thus, in shifting the critical sway speed to a higher level above the speed normally encountered in yard operations, the likelihood of derailments in railway yards has been substantially reduced. As has been previously noted, the occurrence of maximum sway tendencies at a higher speed, which cars attain during acceleration on open track, is not nearly as serious from the standpoint of inducing derailment.

It should also be noted that the suspension system of this invention reduces substantially the divergence between peak spring travel for springs at the inner and outer bolster ends. This is shown in FIGURE 1 by comparing the thickness of the two shaded zones at the peak sway points. Similarly, by referring to FIGURE 2, it will be seen that the improved suspension system reduces the divergence between peak car body movement, relative to a truck, as measured at the inner and outer rail car body sides.

Other comparative tests conducted with the standard cars and cars provided with the stabilizer systems of this invention have produced data indicating that this stabilizing system wlll effect sway reductions up to 69%, with average sway reductions often being measured on the order of 60%. Even with cars which did not normally tend to undergo heavy sway, the incorporation of the stabilizer system of this invention tended to reduce sway on the order of 28%.

In describing the invention reference has been made to a preferred shock absorber structure and installation embodiments. However, those skilled in the railway art and familiar with the disclosure of the invention may well recognize additions, deletions, substitutions or other modifications which would fall within the purview of the invention as defined in the appended claims.

I claim:

1. A railway car stabilizing device comprising:

at least three coil spring means having mutually disdisplaced longitudinal axes, said axes being spaced about a shock absorber receiving pocket;

shock absorber means disposed in said pocket;

a downwardly facing wall portion carried by a bolster of a railway car;

an upwardly facing wall portion carried by a truck of said railway car associated with said bolster;

said shock absorber means being disposed in said pocket in abutting engagement with said downwardly and said upwardly facing wall portions and being restrained from lateral movement out of said pocket by said plurality of coil springs, with each adjacent pair of said plurality of springs being spaced 2. distance less than the width of said shock absorber means;

said shock absorber means comprising an assembly including piston means disposed in slidable stress relieving engagement with one of said bolster and truck wall portions;

said assembly further including cylinder means telescopingly reciving said piston means for hydraulically impeded movement in response to convergence of said wall portions of said truck and bolster, with said cylinder means being disposed in slidable stress relieving engagement with the other of said bolster and truck wall portions; and

said bolster wall portion being retractably convergible with said truck wall portion and operable, in response to convergence with said truck Wall portion, to telescopingly contract said shock absorber means; and

said coil spring means being operable to urge said bolster wall portion, when converged with said truck wall portion, away from said truck wall portion and permit said shock absorber means to telescopingly extend.

2. A railway car stabilizing device comprising:

cylinder means;

piston means telescopingly received within said cyltinder means;

restricted passage means in said piston means providing fluid communications between each of opposite axial ends of said piston means;

said piston means having a high pressure end in engagement with a body of fluid and a low pressure end facing a cavity intended to receive fluid which passes from the high pressure end of said piston means through said restricted passage means;

a piston stabilizing pin projecting longitudinally of said piston means;

a longitudinally extending stabilizing passage formed in said piston means and telescopingly receiving said stabilizing pin;

said stabilizing pin being disposed in slidable and stabilizing engagement with said stabilzing passage continuously throughout the movement of said piston means;

mutually and yieldably convergible ends carried by said cylinder means and said piston means;

means providing rolling and sliding contact between one of said ends and a bolster portion of a railway car; and

means providing rolling and sliding contact between the other of said ends and a truck portion of said railway car; and

a plurality of spaced spring units disposed externally of and peripherally confining said telescopingly assembled cylinder means and piston means, with said plurality of spring units extending between and engaging said bolster and truck portions;

said bolster portion being retractably convergible with said truck portion and operable, in response to convergence with said truck portion, to telescopingly contract said cylinder means and piston means; and

said spring units being operable to urge said bolster portion, when converged with said truck portion, away from said truck portion and permit said cylinder means and piston means to telescopingly extend.

3. A railway car stabilizing device comprising:

a cylinder;

a piston telescopingly received within said cylinder;

restricted passage means in said piston providing fluid communications between each of opposite axial ends of said piston;

a piston stabilizing pin having an axially uniform circular cross-section projecting longitudinally of said piston;

a longitudinally extending stabilizing passage having a circular cross-section formed in said piston, and having a closed end and an open end telescopingly receiving said stabilizing pin;

said stabilizing pin being disposed in slidable and stabilizing engagement with said piston continuously throughout the movement of said piston;

a first end wall connected with said piston and defining a spherical segment facing axially outwardly of said piston;

a second end wall connected with said cylinder and defining a spherical segment facing axially outwardly of said cylinder and away from said first end wall;

the spherical segments of said first and second end walls having axially aligned radii which are axially aligned with the central axis of said piston;

a first, sealed, air cushioning chamber defined by said stabilizer pin and said closed end of said stabilizing passage;

a cylinder shroud carried by said piston disposed in sealing and telescoping engagement with the outer periphery of said cylinder and defining a second sealed, air cushioning chamber axially adjacent one end of said cylinder;

a coil spring extending coaxially about said shroud and said cylinder, said spring being in abutting engagement with said upper and lower end walls;

at least one check valve carried by said piston and openable to permit fluid flow from said low pressure end of said piston to the high pressure end thereof;

at least three coil spring units having mutually displaced longitudinal axes, said coil spring units being spaced about and defining a pocket;

a downwardly facing planar, wall portion carried by a bolster of a railway car; and

an upwardly facing, planar wall portion carried by a truck of said railway car associated with said bolster;

said cylinder and piston being disposed in said pocket in abutting engagement with said downwardly and said upwardly facing wall portions and being restrained from lateral movement out of said pocket by said plurality of coil springs, with each adjacent pair of said plurality of springs being spaced :a distance less than the Width of said assembled piston and cylinder;

said spherical segment of said first end wall providing rolling and sliding contact between said piston means and said planar wall portion of said bolster; and

said spherical segment of said second end wall providing rolling and sliding contact between said cylinder and said planar wall portion of said truck;

each of said planar wall portions being disposed in tangential contact with its respectively associated spherical segment;

a plurality of spaced spring units disposed externally of and peripherally confining said telescopingly assembled cylinder and piston, with said plurality of spring units extending between and engaging said planar wall portions of said bolster and truck;

said bolster wall portion being retractably convergible with said truck wall portion and operable, in response to convergence with said truck wall portion, to telescopingly contract said cylinder and piston;

said spring units being operable to urge said bolster wall portion, when converged with said truck wall portion, away from said truck wall portion and permit said cylinder and piston to telescopingly extend.

4. A railway car stabilizing device comprising:

shock absorbing means having mutually and yieldably convergible ends;

means providing rolling and sliding contact between one end of said shock absorbing means and a bolster portion of a railway car;

means providing rolling and sliding contact between the other end of said shock absorbing means and a truck portion of said railway car;

precompressed resilient means maintaining said shock absorbing means in continuous, resiliently biasing, engagement with each of said portions of said railway car; and

a plurality of spaced spring units disposed externally of and peripherally confining said shock absorbing means and extending between and engaging said bolster portion and truck portion;

said shock-absorbing means comprising piston means connected with one of said mutually convergible ends and cylinder means connected with another of said mutually convergible ends, with said cylinder means telescopingly receiving said piston means;

said bolster portion being retractably convergible with said truck portion and operable, in response to convergence with said truck portion, to telescopingly contract said shock absorber means; and

said spring units being operable to urge said bolster portion, when converged with said truck portion, away from said truck portion, and permit said shock absorber means to telescopingly extend.

5. A railway car stabilizing system having apparatus between each end of each bolster of said car and an underlying portion associated therewith, said apparatus comprising:

cylinder means;

piston means telescopingly received within said cylinder means;

restricted passage means providing fluid communications between each of opposite axial ends of said piston means;

said cylinder means and piston means being disposed in said pocket, externally of said spring units;

said piston means having an upwardly facing end wall;

said cylinder means having a downwardly facing end wall;

means providing rolling and sliding contact between said upper end Wall and an under portion of a bolster of a railway car;

means providing rolling and sliding contact between said lower end wall and a truck portion of said railway car associated with said bolster; and

pre-compressed resilient means between and engaging said upper and lower end walls and maintaining said walls in compressive, elastically yieldable engagement with said bolster portion and truck portion;

said spring units being operable to urge said bolster portion when converged with said truck portion, away from said truck portion, and telescopingly extend said cylinder means and piston means.

References Cited UNITED STATES PATENTS 2,099,240 11/1937 Sproul 2674 2,244,501 6/1941 Pierce 193 X 2,256,868 9/1941 Perkins 105-197 2,393,426 1/1946 Shafer 105-197 2,652,786 9/1953 Kowalik 105-197 1,983,088 12/1934 Kiesel 105-197 2,118,006 5/1938 Couch 105197 2,573,165 10/1951 Settles 105-197 3,073,562 1/1963 Tebb et a1. 248-354 3,351,336 11/1967 Blake 26734 X ARTHUR L. LA POINT, Primary Examiner HOWARD BELTRAN, Assistant Examiner U.S. Cl. X.R. 2673