US3866540A

US3866540A - Roll stabilized railway car

Info

Publication number: US3866540A
Application number: US390726A
Authority: US
Inventors: Sven E Camph
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-02-27
Filing date: 1973-08-23
Publication date: 1975-02-18
Anticipated expiration: 1992-02-18

Abstract

Wheeled vehicle, such as a railway car, is stabilized against ''''roll'''' by moveable means comprising a secondary mass placed in or near the top of the car such that the secondary mass develops a natural frequency substantially equal to the natural ''''roll'''' frequency of the main mass, e.g., the sprung mass of the railway car.

Description

O United States Patent 11 1 1111 3,866,540 amph 1 Feb. 18, 1975 [5 ROLL STABILIZED RAILWAY CAR 2,018,870 10/1935 Paton 296/1 R 6] Inventor: Sven E- p y 516F311 A A nesfridsva en 186F Malmo Y1 R g g 3 5 2,875,706 3/1959 Pacett1.... 105/453 Sweden 2,887,071 5/1959 Settles IDS/392.5 Filed: g 1973 3,712,243 1/1973 Pangalila .1 105/210 X [21] Appl. No.: 390,726

Primary Examzner-M. Henson Wood, Jr. Related Appllcatlo" Data Assistant Examiner-Howard Beltran [63] Continuation-in-part of Ser. Nos. 802,854, Feb. 27, Attorney, Agent, or Firm-Joseph C. Mason, Jr.

1969, abandoned, and Ser. No, 162,993, July 15, 1971, abandoned.

52 u.s.c1. 105/1 A, 105/164, 105/199 A, [57] ABSTRACT ,10 9 ,1 53, 105/210 105/238 R 5 R Wheeled veh1c1e, such as a railway car, 15 stabihzed 51 1111.01. 1361f 5/06, 1361f 5/24, 1361f 5/50 again by mfveable means comprising [58] Field Of Search..... 105/238, 215 R, 210, 392.5, mass Placed the Of the car Such 105/453 1 A 164 199 A 238 267/9 A 8 that the secondary mass develops a natural frequency 296/lR substantially equal to the natural roll" frequency of the main mass, e.g., the sprung mass of the railway [56] References Cited UNITED STATES PATENTS 2 Claims 4 Drawing Figures 2,016,207 10/1935 Lindenberg 296/1 R 1 ROLL STABILIZED RAILWAY CAR BACKGROUND OF THE INVENTION This application is a continuation-in-part to my copending patent application Ser. No. 802,854, filed Feb. 27, 1969, entitled Wheeled Vehicle Stabilizer, now abandoned, and is a continuation-in-part to my copending patent application Ser. No. 162,993, filed July 15, 1971, entitled Wheeled Vehicle Stabilizer" now abandoned. This invention relates to a means for preventing roll in wheeled vehicles, such as a railway car. It also relates to a method of stabilizing a railway car in a manner which will substantially prevent the risk of derailment. It specifically relates to a system whereby a secondary mass and resistance means is cooperatively attached solely to a main sprung mass to prevent excessive oscillation of the main mass.

As those skilled in the art are well aware there are considerable difficulties and complexities in preventing oscillation or vibration between two masses commonly in association as a sprung and unsprung mass. For wheeled vehicles, the sprung mass includes the frame and its associated structure; and the unsprung mass includes the wheel assembly and its associated structure. As described by E. V. Berry in U.S. Pat. No. 2,861,523, a conventional railway car includes a frame on which the car body is mounted. The frame has two longitudinally spaced transverse car bolsters located, typically, at each end of the frame. Each of the car bolsters is connected by a conventional swivel assembly or center bearing means to transversely positioned truck bolsters.

Berry also describes the conventional truck bolster as a heavy, rigid, elongated member that is transversely disposed to the car body and is supported at each end by two vertically positioned helical springs. Situated a distance below the truck bolster is a spring plank on which the lower ends of the helical springs rest. This spring plank rigidly connects two laterally spaced frames which form a part of the truck. The conventional truck provides support means, more fully described in said Berry patent, for journal boxes. The journal boxes rotatably receive the outer end portions of shafts on which are mounted laterally spaced wheels. It is understood that these wheels are of the flanged type and rest on tracks or rails as is conventional with railway equipment.

Since the sprung mass of a railway car is relatively heavy and essentially rigid, its natural or resonant frequency associated with movement is actually relatively low, such as the order of 1 cycle per second. However, the unsprung mass is relatively light in weight compared to the sprung mass and, therefore, will have a natural frequency or resonant frequency which is considerably higher, such as the order of cycles per second. Due to low rail joints which are essentially equal spaced with respect to each other, the oscillation frequency of the unsprung mass in many cases will be in harmonic relationship with the low frequency of the sprung mass. When this occurs there is considerable and many times excessive movement of the sprung mass; such excessive movement usually occurs at one relatively low critical speed of the railway car. The harmonic relationship actually increases with time so that for the case of railway cars the high frequency oscillation of the unsprung mass will eventually cause the sprung mass to oscillate or roll through such a transverse angle that derailment will occur. As used herein, the terms oscillate, roll, and words of similar import are intended to embody movement of the main mass back and forth in a direction substantially transverse to the line of movement of the combined sprung and unsprung mass; i.e., if movement line is northsouth, then roll would be east-west, etc.

Referring again to the description contained in Berry US. Pat. No. 2,861,523, it is described that during travel along the rails, the wheels encounter the irregularities therein whereby a transverse oscillation or rolling motion relative to the rails is imparted to the springsupported truck bolster. The bolster in turn imparts such rolling forces to the car bolster through the center bearing means or pivotal connection which connects the car bolster to the truck bolster. The railway car therefore rolls with respect to this pivotal connection as its focal point.

In order to overcome this undesirable effect, the prior art hasfairly consistently attempted to solve this problem of oscillation between the sprung and unsprung mass by dampening or hindering the movement of the unsprung mass so that its resultant oscillation or vibratory forces will not be transmitted to the sprung mass in an undesirable way. Generally, the dampening action has taken the form of a hydraulic shock absorber, spring, and/or frictional devices to prevent the unsprung mass from having a high frequency coupled with large amplitude of vibration.

In spite of efforts to dampen the vibration between the sprung and unsprung mass, there still remains the problem of derailment associated with railway freight cars. The problem persistently remains because there must be a balance between dampening resistance and oscillation amplitude. By this it is meant that increased dampening renders the sprung mass of such rigidity with respect to the sprung and unsprung mass that damage may occur to cargo being carried in, for example, a railway car. On the other hand, decreasing the magnitude of dampening will aggravate the oscillation problems referred to hereinabove. Therefore, dampening or controlling the oscillation of the unsprung mass has not been entirely satisfactory in the solution of rock and roll problems associated with railway freight cars.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to devise a means for stabilizing the roll" tendency of railway freight cars.

It is another object of this invention to provide a wheeled vehicle, such as a railway freight car, which is stabilized against roll by moveable means comprising a secondary mass placed in a wheeled vehicle such that this secondary mass develops a natural frequency substantially equal to the natural roll frequency of the main mass, e.g., the railway car.

It is a further object of this invention to provide a means for applying a control force solely to an essentially rigid sprung mass in such a way that the resulting force is equal to or substantially equal to the force exerted on the sprung mass from the unsprung mass.

These and other objects and advantages inherent in the invention will become apparent from the following description and the accompanying drawings in which:

FIG. 1 is a diagrammatic representation of a railway car showing one placement of the secondary mass;

FIG. 2 is an end view of such a railway car indicating the placement of the secondary mass;

FIG. 3 is a diagrammatic representation of forces which are applied to the railway car as it moves along the track; and

FIG. 4 is a more specific diagrammatic representation of the geometry for a selected secondary mass.

Therefore, the present invention provides a wheeled railway car which comprises in combination: (a) a body constituting a relatively rigid main mass; (b) wheels including bolster means resiliently supporting said body in sufficient manner for rolling movement in a first direction, said movement introducing a force to said main mass thereby inducing said main mass to perform substantially vibratory motion about pivotal connection between said main mass and said bolster means having a natural oscillation frequency in a second direction transverse to said first direction; (c) a secondary mass slidably mounted on said main mass in a plane of substantial main mass oscillation amplitude about said pivotal connection for movement in said second direction; and, (d) resistance means associated with said secondary mass restricting the linear displacement of said secondary mass, whereby said secondary mass develops a natural oscillation frequency substantially equal to said natural oscillation frequency of said main mass.

Another embodiment of this invention is the wheeled vehicle hereinabove wherein said resistance means constitutes spring means attached at one end of said secondary mass.

A further embodiment is a wheeled vehicle substantially rectangular shaped railway car which comprises, in combination:

a. a body constituting a relatively rigid main mass;

b. wheels including bolster means resiliently supporting said main mass in sufficient manner for rolling movement in a first direction, said movement introducing a force F, to said main mass thereby inducing said main mass to perform substantial vibratory motion having a natural oscillation frequency about pivotal connection between said main mass and said bolster means, in a second direction laterally transverse to said first direction;

0. a secondary mass having a weight of at least 825 pounds (375 kilograms) slidably mounted on said main mass in a plane of substantial main mass oscillation amplitude about pivotal connection between said main mass and said bolster means induced by said force F, for movement in said second direction, with the weight of such secondary mass correlated to the weight of said main mass to produce a substantially equivalent opposing force F; on said main mass to thereby minimize transverse roll motion of said main mass about said pivotal connection; and

d. resistance means associated with said secondary mass restricting the linear displacement of said secondary mass, whereby said secondary mass develops a natural oscillation frequency substantially equal to said natural oscillation frequency of said main mass.

A specific embodiment is a railway car according to claim 1 wherein said secondary mass has a weight rela tionship to said main mass sufficient to minimize the transverse roll motion of said main mass at the critical speed of said rolling movement in said first direction.

Thus, theessence of the present invention is embodied in the concept of placing a secondary mass operating in conjunction with resistance means at the point of substantial amplitude of oscillation for the car body,

e.g., at or near the top of the car body, or main mass such that said oscillation is about the pivotal connection between the car body bolster and the truck bolster. The effect of this secondary mass at this particular location is to effectively create a compensating force which nullifies the force which is transmitted to the main body from deviations of the unsprung mass, as previously mentioned.

DETAILED DESCRIPTION OF THE INVENTION It has been recognized by those skilled in the art that railway cars, such as a IOO-t'on hopper car, will have a tendency to derail at low speeds, and that for the most part these derailments are associated with excessive car rolling. The severity of the roll motion, of course, depends upon the trains speed and up to the critical speed tends to increase as the speed increases. Furthermore, there is a critical speed at which the frequency of traversing rail joints corresponds to the frequency'at which the car body rolls naturally. In many cases this critical speed may be 14-17 miles per hour. At the natural oscillation frequency, the roll motion about the pivotal connection between the car body bolster and the truck bolster can be great enough to alternately lift the wheels at each side of the car every rail length. There comes a time at one such critical speed (or narrow range of low speeds) where the lifting of the wheels is of such magnitude that derailment occurs. As used herein, the term natural frequency or words of similar import are designed to include that frequency which is commensurate with the critical speed surrounding the environment to which the'wheeled vehicle is subjected.

The tendency of a wheeled vehicle, such as a railway car, to roll excessively at relatively low speeds, i.e., critical speed depends upon many factors surrounding the environment. Some of the important factors include train speed, wheel lift of the leading wheel at each side of the car, roll angle of the car body at the center of gravity, lateral displacement of car body at the center of gravity, vertical displacement of car body at the center of gravity, spring displacement at each side of the car body, relative vertical displacement between the car body and truck bolsters, lateral truck bolster movement relative to one side frame, vertical load on each side frame, lateral load on each side frame, lateral acceleration of the car body at the center of gravity, etc. Many of these factors tend to cooperate to produce the excessive roll motion of the wheeled vehicle. It is difficult to say which, if any, of these factors are more or less important. Each plays its own part in defining the environment to which the wheeled vehicle is subjected at critical speed.

It is important to note that the present invention has unique application in preventing roll motion of a wheeled vehicle, such as a railway car. The principle upon which the present invention is based embodies the concept of a secondary mass oscillating about the pivotal connection between the car body bolster and the truck bolster creating a force sufficient to nullify the force which is transmitted to the relatively rigid car body from the unsprung mass or wheel assembly. It does not relate to a system for dampening or preventing the high frequency oscillation or vibration of the unsprung mass, nor does the present invention have any,

direct influence on forced motions commonly called bounce and pitch. As used herein, the term relatively rigid" as applied to the body or main mass is intended to embody the principle that the railway car body moves as one rigid part and is not flexible within itself with respect to the individual members making up the body or main mass.

Satisfactory secondary mass and resistance means combination includes a solid substantially rectangular metal mass having a single spring attached to one end of the mass; a solid mass having attached two springs; one attached at each end of the mass; a wheel mass substantially circular which rolls having attached at each side along its axis a torsion bar made of metal or preferably made of rubbery material which takes the torque developed in sheer stress; etc.

Preferably, the resistance means comprises a spring system; either the single spring or two-spring arrangement described hereinabove. The spring characteristic will, of course, vary considerably depending upon the diameter, materials of construction, imposed stress, etc. of the spring. However, the spring characteristic should be designed such that the secondary mass does not hit or strike the sides of the wheeled vehicle or main mass, should be such that the secondary mass develops a natural frequency of its own, etc. In other words, the spring should not be so rigid as to prevent movement of the secondary mass, nor so flexible that the secondary mass travels freely back and forth essentially out of control.

This secondary system may be dampened or undampened; if dampened: mechanical, pneumatic, or hydraulic means may be used for such dampening in combination with the secondary mass and resistance means. The secondary mass may be any heavy object, such as iron; lead; steel; hollow cylinders filled with a liquid, such as water, mercury, etc.; and the like.

The invention may be more fully understood with reference to the appended drawings which represent schematically one embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS Referring now to FIG. 1, the principles on which the invention is based are illustrated with the main mass being supported on unsprung wheel assembly 11 having associated therewith 12 which cooperates in the usual manner to move the main assembly 10 in a forward direction along rails shown schematically at 13. Specific details of this assembly have been omitted since same are conventional. However, U.S. Pat. No. 2,861,523 provides generally the typical components making up this assembly. The secondary mass system is shown in FIG. 1 as being secondary mass 14 having connected thereto a single spring 15. It is to be noted that FIG. 1 illustrates three positions of the secondary mass substantially symmetrical along the length of the railway car. However, it is to be understood that the concepts of the present invention include either one such secondary mass system or a plurality of secondary mass systems, such as from 1 to 10 or more secondary mass systems placed in proper position along the transverse plane of the wheeled vehicle.

FIG. 2 illustrates the end view of railway car 10 which indicates the attachment of main mass 14 to

spring

15 and 16 such that movement of said secondary mass forces one spring into compression and the other spring into tension.

The dynamics of the system are shown schematically in FIG. 3. The at rest position is denoted by the vertical axis and the spring movement 102 of spring 12. With the rolling movement of the car and the changes of the irregular surface represented by rails, the movement up and down of spring 12 through plane 102 creates a force P, which if it is assumed acts upon one truck 11, forces verticle plane 100 into position 103 by rotation or pivoting about the connection point between the car bolster and the truck bolster, schematically shown as the intersection of line 100 and line 103. The movement of main mass 10 to position 103 forces secondary mass 14 to move out of the vertical position along the plane represented 101 to position 104. It is noted that spring 15 is in tension and spring 16 is in compression. As main mass 10 begins to move back toward a vertical position 100, mass 14 has an inertia which tends to keep it out of phase with the roll frequency of main mass 10. Consequently, as secondary mass 14 begins to move back in a transverse direction, main mass 14' is again moving to the right toward the plane represented by 103. At that moment secondary mass 14 is actingwith a force F against force F ..The amount of secondary mass 14 coupled with its spring resistance acts through the distance represented by the length of the line 100 to create force F The force F, is represented by the amount of force acting across the distance between the end point of 100, said pivotal connection point, and the plane represented by 102.

By operating the system in accordance with the teachings -of this invention, resulting force F very quickly reaches and is equal to or substantially equal to resulting force F,. It is recognized, however, that it is not necessary that the torque on the main mass from force F be exactly equal to F only that these two forces be substantially equal so that main mass 10 is stabilized with substantially no movement whatsoever regardless of the up and down movement represented by 102.

FIG. 4 presents in greater detail a preferred geometrical configuration of the secondary mass system. The reason for producing mass 14 as a solid slotted contiguration is to obtain maximum weight passing through maximum distances permitted by

spring

15 and 16. In this way, greater flexibility may be built into the secondary mass system to cover a wide range of resulting force E, which is transmitted to main mass 10 over any irregular surface, such as the rail system 13.

The following example will illustrate one aspect and one embodiment of the present invention.

EXAMPLE With reference to FIG. 3, it is assumed that the force F acts on one side of one truck at a time. It is further assumed that main mass 10 represents a lOO-ton railway car. Other weights are also assumed for purposes of the calculation which presents the hereinbelow summarized data. By assuming that the rail joints will deflect three-fourth inch for a 100-ton car and commensurate deflections for other weights for the main mass, the following calculated data, utilizing well-known mathematical concepts, produced according to principles of the present invention, results in the following table which correlates the various weights of the main mass to the weight of the secondary mass in order to substantially stabilize the main mass passing through a fixed environment at its critical speed:

Thus, it can be seen that a relatively small secondary mass, say of 3,036 pounds 1,380 kilograms) can stabilize a lOO-ton railway car at its critical speed against rock and roll if utilized according to the teachings of thistinvention. In effect, the secondary mass exerts a force F substantially equal or, preferably, exactly equal to F thereby preventing the car from undergoing roll.

Different secondary mass weights may be obtained by those skilled in the art depending upon the other factors which may influence the relationship, such as spring characteristic, geometry of the car body, etc. However, the above data represents the kind of secondary mass which will stabilize a given car at its critical speed which, of course, depends to a large extent upon the total environment to which the railway car is subjected. Of course, each car will have to be calculated and designed according to its own characteristics and according to its own predetermined environment.

While the invention has been described as being applied to railway cars, it will be apparent that the system may be applied to other wheeled vehicles or to vibrating systems which are subject to very low frequency oscillatory vibration. The force need not necessarily be applied from an unsprung mass to a sprung mass, but might conceivably originate on the main mass itself. It

will be understood that the details of construction of the secondary mass system and the means for mounting the secondary mass system on the main mass may take various forms depending upon the particular system or vehicle to which the secondary mass system is being applied. Such changes and others may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

The invention claimed is:

1. In a railway car supported on a truck having a spring mounted truck bolster and including rigid wheels riding on rails pivotably connected to car bolster through center bearing means, a mass slidably mounted contiguous to the top of said car in a plane of substantial car body oscillation amplitude about said pivotal connection for restricted movement in a laterally transverse direction to the longitudinal axis of said car, said mass having sufficient weight to create an opposing force sufficient to minimize the transverse roll motion of said car body about said pivotal connection.

2. In a railway car comprising in combination:

a. a body constituting a relatively rigid main mass including body bolster means; and

b. truck means including wheels riding on rails and a truck bolster resiliently supporting said body through center bearing means connecting said truck bolster and said body bolster in sufficient manner for rolling movement on said rails in a first direction, said movement introducing a force to said main mass through said center bearing means thereby inducing said main mass to perform substantial vibratory motion having a relatively low natural oscillation frequency in a second direction laterally transverse to said first direction; the improved construction comprising in combination:

c. a secondary mass slidably mounted on said main mass in a plane of substantial main mass oscillation amplitude about said center bearing means for movement in said second direction, said secondary mass having a weight relationship to said main mass sufficient to minimize the transverse roll motion of said main mass about said center bearing means at the critical speed of said rolling movement; and

d. resilient resistance means associated with said secondary mass restricting the linear displacement of said secondary mass, whereby said secondary mass develops a natural oscillation frequency substantially equal to said natural oscillation frequency of said main mass such that said railway car is prevented from derailing at said critical speed.

Claims

2. In a railway car comprising in combination: a. a body constituting a relatively rigid main mass including body bolster means; and b. truck means including wheels riding on rails and a truck bolster resiliently supporting said body through center bearing means connecting said truck bolster and said body bolster in sufficient manner for rolling movement on said rails in a first direction, said movement introducing a force to said main mass through said center bearing means thereby inducing said main mass to perform substantial vibratory motion having a relatively low natural oscillation frequency in a second direction laterally transverse to said first direction; the improved construction comprising in combination: c. a secondary mass slidably mounted on said main mass in a plane of substantial main mass oscillation amplitude about said center bearing means for movement in said second direction, said secondary mass having a weight relationship to said main mass sufficient to minimize the transverse roll motion of said main mass about said center bearing means at the critical speed of said rolling movement; and d. resilient resistance means associated with said secondary mass restricting the linear displacement of said secondary mass, whereby said secondary mass develops a natural oscillation frequency substantially equal to said natural oscillation frequency of said main mass such that said railway car is prevented from derailing at said critical speed.