US2903976A - Bolster rolling and lateral control - Google Patents

Description

Sept. 15, 1959 w. T. ROSSELL BOLSTER ROLLING AND LATERAL CONTROL Filed July 14, 1953 ATTORNEY k 4 a a 2, g u m 0. m m P m M r u Vl/lZr/l/ m m w m m United States Patent BOLSTER ROLLING AND LATERAL CONTROL William T. Rossell, New York, N.Y., assignor to Transit Research Corporation, New York, N.Y., a corporation of New York Application July 14, 1953, Serial No. 367,859

2 Claims. (Cl. 105-197.2)

This invention relates to rail trucks and has for its object to provide for lateral and rolling motions of a body supported thereby and to provide means for requiring such motions to combine with each other with the result that a composite pattern of motion results. The new pattern includes both motions which must occur in phase and must be of the same frequency, amplitude and direction, thus providing a truck operation in which the major number of rolling and lateral movements are quickly damped out or inhibited.

In a rail truck it is conventional to provide a bolster resiliently supported from a main frame. The bolster is capable of purely vertical relative movements and of purely lateral relative movements with respect to the main frame. Rolling motions of a body can occur which may be accepted by the springs as a purely vertical movement of one side of the bolster but the rolling motions generally occur in conjunction with lateral motions of the bolster. If a body rolls, for instance, to the right, the bolster may be centered, it may be at its outermost position to the right, it may be at any intermediate position, the bolster may be on its way either out or back, or it may be at any position to the left. Such rolls occur, for instance, as a result of a wheel passing a low spot in the rails. Rolling also occurs as a result of hunting motions when a leading wheel flange suddenly alters the direction of the wheels with respect to the rails. In addition, a roll may follow a maximum outward swinging of the bolster as a relief mechanism to prevent de-railing.

Now, the lateral movements of a bolster have one natural frequency which may change with increasing loads and the vertical movements have another natural frequency which generally changes With increasing loads. In any event the two frequencies are never the same. Since rolling movements may be composed, momentarily, of any combination of lateral and vertical, it can thus be seen that such motions are wholly unpredictable either as to amplitude or frequency. They are generally controlled as to amplitude by various devices including shock absorbers, snubbers, etc., but, so far as is known, no successful attempt has heretofore been made to control the frequency except by indirection. The principal object of this invention is to teach the frequency of the rolling and lateral motions to be the same and to occur in the same direction and at the same time.

Consider now the behavior of two innning trucks supporting a car body. The axles of the rear truck are continuously changing their relation with respect to those of the lead truck. When the lead truck angles toward one rail and the rear truck angles toward the opposite rail the bolsters of the two trucks responsively move laterally in opposite directions. If the movements are resonant or continuous we have the phenomenon known as fishtailing, which is one of the most obnoxious of all body motions. According to this invention all lateral movements of the bolsters are converted into rolling motions about some point which thereby obviates fish-tailing for p 2,903,976 Patented Sept. 15, 1959 ice the reason that the two ends of a car body can not roll in opposite directions. It should be noted that if the bolster were merely prevented from moving laterally fishtailing could not occur, but rolling would be aggravated for all other conditions so that it is, therefore, essential to permit lateral motions to occur but to cause them to assume the characteristics of roll in the manner herein described.

More specifically, it is the object of this invention to provide a rail car composed of a body and a truck equipped with a bolster; to mount the body on the bolster and to anchor the bolster to the main frame of the truck in such manner that all lateral motions of the body and bolsters and all rolling motions of the body must occur about a point remote from the normal center of gravity of the car body and preferably well below the point of support of the body on the bolster. As will be hereinafter explained, the point of anchorage need not be fixed but may be made variable through resilient mountings. The point is that the lateral component of the roll is increased and the lateral swinging motions of the bolster must occur as a rotation about the same point whereby the frequencies of the two must be the same.

It should be stated that advantages appear to flow from this invention other than those stated. The results appear so far reaching that they appear applicable to advantage to any type of truck whether freight or passenger, Whether with or without swing links and whether with or without equalizer bars. It is believed that the numerous good results flow, in large part, because this invention severely limits many body motions of large amplitude because it deals with the forces while they are acting through small physical dimensions. For instance, a body may move several inches in response to a wheel movement of only a fraction of an inch.

Other objects and advantages will become hereinafter more fully apparent as reference is had to the accompanying drawings in which my invention is illustrated as applied to one type of truck and in which Figure 1 is a side elevation of a rail truck, and

Figure 2 is a vertical section taken along the line 22 of Figure 1.

More particularly, 1 indicates the main side frames of a rail truck which are supported by journal bearings 2, which receive the axles 3. Wheels 4 are mounted on each end of each axle. Supported by the side frames 1 are main truck springs herein shown as being composed of rubber springs 5, each nested within a coil spring 6 which, in turn, supports the bolster 7.

Each spring 5, 6 has an upper spring cap 8 and a lower cap 9. Each cap has a rocker 10 on the exterior surface thereof for weakening the lateral resistance of the springs 5, 6, the rockers 9 contacting the bolster 7 and the side frames 1, respectively. The springs 5 and 6 support the bolster 7 so that it is capable of vertical, lateral and rolling motions with respect to the side member 1.

Intermediate the ends of the bolster 7 is a center bearing 11 having a deep center pot 12 extending therebelow. The center bearing 11 receives the king pin 13 of the car body 14, the king pin extending downwardly into and substantially through the center pot 12.

Preferably at or near the bottom of the center pot 12, I provide a collar 15 which encircles the center pot and which has a bracket 16 to hold a pin 17. Around the pin 17 is a rubber sleeve 18 which is housed by the end of a link 19. The other end of the link 19 is secured through a rubber bushing 20 to the bracket 21 fixedly secured to a side member 1. The bushings 17 are not essential but are desirable to cushion violent shocks and to damp out high frequency vibrations from the truck frame to the car body.

The operation is as follows: assume the parts in the position shown in Figure 2 and assume that a spring cap 9 is suddenly lowered as by one or both wheels therebeneath suddenly encountering a low spot in the rails. The deep pot 12 and the long kingpin 13 require that the body 14 and the bolster 7 move together. The body 14 will tend to roll about its center of gravity but is restrained from doing so by its king pin which, in turn, is restrained by the linkage 19. The result is that the body and the bolster roll about the attachment of the linkage 19 to the pot 12. The roll occurs but it occurs about a new point 18 and instead of a sample roll depressing the springs 5, 6 on one side of the truck, the bolster is required to move laterally.

Now suppose that the wheels have recently encountered an obstruction which causes the flange of at least one of them to approach a rail to the point where it is given a new direction toward another rail. The body 14 will tend to continue its direction and hence the bolster will swing against the resistance of the springs and 6. But its lateral swinging must occur as an oscillation about the point 18 and this restraint requires that the bolster go into a rolling motion.

From the two above examples of running conditions we see that the truck may encounter a condition which would cause pure rolling motions of a bolster and the body carried thereby in conventional truck construction and that the truck may encounter a condition where pure lateral swinging of the bolster would occur conventionally but that the response of the bolster according to this invention is the same in both instances. The lateral and rolling reaction and the frequency are identical and coincident.

Now, if we consider any one of the innumerable conditions made up of a combination of pure rolling and pure lateral bolster motions it will be found that the same rule will always hold truethe response of the bolster must be a combination of lateral movement and roll and the frequency of the lateral component will always be the same as that of the rolling component.

At first blush it may appear that car bodies controlled according to this invention will be subjected to excess rolling but that is contrary to actual fact. The explanation is found in a study of the behavior of the car as a whole, which has a truck supporting each end. The two trucks never act exactly the same except momentarily. When the bolster and car body of each end of a car is disciplined to act according to the rigid pattern of be havior required by this invention and when the two ends are acting in accordance with different patterns of behavior practically all of the time it is found that a large percentage of the car body motions set up at one end of the car counteract those set up at the other end and that the car body has a remarkable smooth operation. The

lateral and rolling action must be the same in amount and direction on the two trucks. This creates a better ride throughout the car body analogous to the better ride now had in the center of the car due to the averaging of the impulses received by the two trucks from the tracks. True resonant oscillation is obviated.

If the vertical springing is such as will provide constant natural frequency, which the bolster springs 5 and 6 do, then the control rod will provide constant natural lateral frequency.

The invention is herein shown as being applied to a well known type of city transit truck. It may also be applied to all other types of trucks it due consideration of the requirements of the principles here stated are recognized. For instance it may be applied to an equalized truck either with or without swing links in which case the link 19 should be attached at one end to the equalizer bar and at its other end to a low point below the center bearing even if a projection must be welded onto the bolster. Where it is not possible to anchor the linkage 19 to an unsprung member then it should be anchored to a frame part which has little or no lateral movement with respect to the journal bearings and axles.

It should be noted also that while this invention may be applied to a bolster supported by swing links that the use of this invention eliminates the need for swing links insofar as present tests have been conclusive. Elimination of swing links is desirable in that they require articulations which, in turn, require maintenance.

The application of the invention to all types of trucks now in use is not illustrated since the principle is simple and may be re-stated as selecting a new point of roll, preferably at the level of the axle axes and using that point of roll as the center of oscillation about which all lateral movements of the body and bolster must move, the point of oscillation being anchored, preferably, to an unsprung truck member and in any case to a member which has highly restricted lateral movements with respect to the axle journal bearings.

Protection is requested as defined by the scope of the appended claims.

What I claim is:

1. In a rail car, a truck having a main frame comprising side members, a bolster, springs supporting said bolster from said side members, said bolster having a center bearing for the support of a car body, a king pin on said body anchoring said body to said bolster for lateral, rolling and vertical movements therewith, said bolster having an extension below said center bearing extending downwardly therebelow to a point remote from the center of gravity of said body, a single rigid link pivotally anchoring a point on said extension near the bottom thereof to a single one of said side frames, said link maintaining a fixed arcuate distance between the bottom of said extension and the side frame to which said link is attached, said link causing all lateral and rolling motions of said bolster and said body to occur as oscillations about the point of attachment of said link to said extension.

2. In a rail car, a car body, a pair of trucks each comprising side members and a bolster supported thereby, each of said bolsters having a center bearing supporting one end of said car body, each of said bolsters being movable vertically, laterally and in rolling movements with respect to its side members, means connecting said body to said bolsters for coincidental lateral, rolling and vertical movements therewith, each of said bolsters having an extension thereon extending downwardly to a point remote from the center of gravity of said body, a rigid link pivotally anchoring a point on each of said extensions near the bottom thereof to a single side member of its truck, each of said links requiring all rolling and lateral movements of its bolster to occur about its point of attachment to its extension, said links in response to all lateral movements of both of said bolsters causing a rolling component, said body resisting rolling components of opposite direction imposed thereon by the bolsters of different trucks when said bolsters tend to move in opposite lateral directions thereby obviating the car body motion known as fish-tailing.

References Cited in the file of this patent UNITED STATES PATENTS 825,723 Hatchet July 10, 1906 1,536,142 Priebe May 5, 1925 2,244,501 Pierce June 3, 1941 2,352,163 Buckwalter June 27, 1944 2,576,367 Spearman Nov. 27, 1951 2,636,451 Watter Apr. 28, 1953 2,652,001 Travilla et a1. Sept. 15, 1953 2,700,346 Rossell Jan. 25, 1955 2,743,681 Rossell May 1, 1956

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