US 3905305 A
A railway truck comprising two-wheel and axle sets held in spaced relationship by a pair of side frames, a static bolster spanning, and holding in square relationship, the side frames, an active bolster overlaying the static bolster and supported thereon for limited vertical and lateral movement by springs the number, capacity and size of which can be varied depending upon the physical characteristics of the vehicle body supported on the center bearing of the active bolster.
Claims available in
Description (OCR text may contain errors)
'United States Patent 1191 Cope [4 1 Sept. 16, 1975 SNUBBED RAILWAY TRUCK BOLSTER  Inventor: Geoffrey Wilton Cope, Williamsville,
 Assignee: Dresser Industries, Inc., Dallas, Tex.
 Filed: July 30, 1973  Appl No.: 383,863
 US. Cl...... 105/197 D; 105/182 R; 105/197 R;
105/208; 267/4  Int. Cl. B61F 5/06; B61F 5/12; B61F 5/50;
F16F 1/12  Field of Search 105/182 R, 197 R, 208, l05/208.l, 208.2, 198, 202, 203, 197 D; 267/4  References Cited UNITED STATES PATENTS 384,317 6/1888 Hubbard 105/197 R X 694,473 3/1902 Hobbs 105/197 R X 1,141,436 6/1915 Turner 105/208.2 X
2,094,557 9/1937 Couch 105/208 X 2,139,434 12/1938 Barrows 105/208 X 2,208,425 7/1940 Kjolseth 105/182 R 2,316,046 4/1943 Buckwalter... 105/208 X 3,517,620 6/1970 Weber 105/198 3,670,660 6/1972 Weber et a1. 105/208 X 3,768,419 10/1973 Howard 105/182 R Primary ExaminerM. Henson Wood, Jr. Assistant Examinerl-loward Beltran Attorney, Agent, or FirmRaymond T. Majesko ABSTRACT A railway truck comprising two-wheel and axle sets held in spaced relationship by a pair of side frames, a static bolster spanning, and holding in square relationship, the side frames, an active bolster overlaying the static bolster and supported thereon for limited vertical and lateral movement by springs the number, capacity and size of which can be varied depending upon the physical characteristics of the vehicle body supported on the center bearing of the active bolster.
6 Claims, 4 Drawing Figures PATENTED SE? 1 6 I975 SNUBBED RAILWAY TRUCK BOLSTER This invention relates to railway freight car threepiece snubbed trucks and more particularly to an improved suspension system incorporated into a novel two-piece bolster and an improved side frame-bolster interlocking arrangement.
The currently used conventional three-piece railroad freight car truck has proven to be inadequate for the prevailing operating conditions particularly in the one hundred ton capacity variety.
The inadequacy stems from a variety of causes, such as poorly maintained track, higher operating speeds, and cars with high center of gravity and truck center length equal or close to rail joint spacing, but there are some basic truck design causes also.
For instance, up until the early l950s freight car trucks were equipped with spring planks which tied the side frames together and provided a means of holding the side frames in tram (square). They were also equipped with the so-called plain or friction journal bearings which permitted a degree of lateral freedom to the wheel and axle sets which therefore were able to accommodate the majority of the lateral deviations of the rails, and also to permit the wheels to hunt relative to the side frames.
Later trucks have eliminated the spring plank and at the same time utilized roller bearings which do not provide any lateral freedom of the wheel and axle sets, consequently, the natural hunting tendency of the wheels and axles due to initial conicity of the new tread or the developed profile of the worn tread is transmitted to the truck side frames and the truck hunting tendency is increased over and above that normally required for efficient tracking.
Superimposed on the increased hunting tendency there can be a synchronous roll condition, called rockand-roll in the industry, to which many high center of gravity one hundred ton cars are subject due to the matching of the car body natural roll frequency with low rail joints at a critical speed which falls into the normal operating speed range on many branch lines.
The destructive action of the hunting and rock-androll condition is well known in the industry and many attempts have been made to control it. Most of them, however, have modified the effect but have not treated the cause.
Another very destructive condition is the so-called nosing" condition that results when truck hunting and car body yaw frequencies match to cause violent lateral action which unsquares the truck first in one direction and then the other.
Equally destructive is the crabbing or lozenging condition which is the result of a truck going out of tram due to inefficient squaring means and staying in that condition due to the leading wheel flange drag on the rail.
These conditions have also been the subject of corrective measures but with little significant success.
Accordingly, it is among the objects of this invention to provide a snubbed truck of the general three-piece basic design that will provide the means to distribute the suspension springs in a manner to reduce the natural frequency of the body roll and a means to provide a positive interlock against horizontal unsquaring of the bolster-side frame connection.
In accordance with the invention, there is provided a railway car truck having a two-piece bolster assembly. The lower piece or static bolster connects and holds the side frames in tram (square) while permitting vertical articulation of the side frames about the bolster longitudinal axis. The upper piece or active bolster is supported on the lower piece or static bolster by means of suspension springs to provide limited vertical and lateral movement of the active bolster.
Ample space is provided for distributing and locating the suspension springs so that their centroid or virtual point of support on each side can be adjusted relative to the longitudinal center line of the car body allowing the car body natural roll frequency to be tailored (predetermined) relative to the car body mass and center of gravity thereby avoiding the destructive rock-androll condition.
IN THE DRAWINGS FIG. 1 is a side elevation view in partial cross section taken along lines l-l of FIG. 2.
FIG. 2 is a partial front elevation view partly in cross section taken along line 2-2 of FIG. 1.
FIG. 3 is a plan view in phantom of a typical spring arrangement on the static bolster.
FIG. 4 is an elevation view in cross section taken along lines 4-4 of FIG. 3.
Referring now to the drawings for a better understanding of the invention, it will be seen that the freight car truck 1 incorporating the invention comprises a pair of side frames 2 each supported at each end on the journal bearings (not shown) of the wheel and axle assembles (not shown) in a conventional manner. Intermediate their ends the tension and compression members 3 and 4, respectively, are spaced from each other and interconnected by a pair of integral vertically extending columns 5 spaced from each other lengthwise of the side frame to define a bolster opening 6 therebetween.
The bolster 7 is comprised of two partsthe static bolster 8 and the active bolster 9 with suspension springs 10 therebetween.
The static bolster 8 is a beam of channel section with the flanges 11 extending vertically upward and of greater depth in the center than at the ends. The underside of the static bolster is provided with downstanding flanges l2 and 13 extending the full width of the section and spaced longitudinally of the bolster in a manner to engage the tension members 3 of the side frames 2 and hold them in square relationship with the bolster. The outer flange 12 is of limited depth to facilitate assembly. Unwanted disassembly during a derailment can be positively prevented by applying a stop 26 in the column above the static bolster flange 11.
The underside of the bolster 8 between the flanges 12 and 13 that contacts the top surface 16 of the side frame tension member 3 is preferably provided with a beveled or arcuate surface 17 having as its center an axis normal to the vertical plane of the side frame. Sufficient clearance is provided between the bolster flange 11 and the confronting transverse faces 19 of the guide columns 5 to allow rocking to the extent necessary to negotiate track spirals and other vertical track profile configurations such as humps, sags and cross level deviations.
The active bolster 9 is of the same general design as a conventional bolster with inbuilt snubbing wedge pockets for accommodating a dampening or snubbing wedge 27, except the depth at the center is rreduccd and the bottom wall for almost the full length of the bolster is utilized as a spring seat to cooperate with the helical coil springs supported on the static bolster 8 and located to provide the minimum body roll frequency consistent with all other factors.
The lower wall 21 of the active bolster 9 would ideally be flat and parallel to the spring seat surface 22 of the static bolster with the car stationary on a flat level tangent track, however, it may be necessary to deviate from this ideal condition to satisfy strength requirements of the static and/or active bolsters.
The truck side frames 2 are similar to the conventional designs with the exception of the spring seat 22 and bolster opening 6 which have been modified to suit.
The tension member 3 of the side frame 2 is of rectangular section to cooperate with the downstanding flanges l2 and 13 for positive squaring.
The bolster opening 6 is rectangular and with the usual increased width portion below the column friction surfaces required for admitting the static bolster to pass during assembly.
Both static and active bolsters are provided with spring retaining means 22 preferably shallow depressions or low profile spuds or bosses. These are provided at numerous locations on the bolsters between the center lines and ends thereof so that the spring members may be laterally shifted to the positions desired between the bolsters to enable a car body natural roll frequency to be tailored relative to a car body mass and center of gravity. In other words, as shown in FIG. 3, the bolsters contain a surplus of spring retaining means 22 over and above those necessary to accommodate the maximum number of springs required to support the full car and lading condition. The spring members 10 are disposed in selected ones of the spring re-. taining means in the predetermined positions.
In other embodiments an elastomer mat or mats could be disposed on surface 16 to provide articulation at the static bolster-side frame connection instead of using the arcuate or beveled surface 17. Lateral limiting of the active bolster could be achieved by providing lugs and stops on the static and active bolsters to remove the need for lateral contact at the side frame columns.
Vertical snubbing could be supplemented by adding friction snubbers at the center line to be carried by the static bolster and frictionally engage the active bolster. The advantage of this arrangement would be that the vertical snubbing would be increased without adding to the spring group transmissibility in the rocl -and-roll condition. Also, the additional friction snubbing could be utilized to lower the friction wedge pressure to obtain equivalent snubbing with a lower wear rate and longer component life. The bolster could be designed with the vertical flanges at the ends extending upward sufficiently to provide the friction surfaces to cooperate with the wedges.
The foregoing should be construed as illustrative and not in limitation of the invention.
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. In a railway car truck comprising a pair of side frames supported on wheel and axle assemblies, said side frames having an upper compression member and a lower tension member spaced therefrom and interconnected by a pair of vertically extending columns spaced from each other longitudinally to define a bolster opening therebetween, a two part bolster assembly consisting essentially ofa static bolster and a dampened active bolster, the static bolster being a beam of channel section with opposed flanges extending vertically upward between the pair of side frames to define a spring seat surface and having a pair of downwardly extending flanges at each end thereof spaced longitudinally of the bolster to form longitudinal cavities which envelop and contact the tension members of the side frames and holds them in square relationship with the bolster, said active bolster disposed above the static bolster and extending between side frames, the active and static bolsters each having a surplus of spring retaining means over and above those necessary to accommodate the maximum number of springs required to support the car in full lading condition, at spaced apart locations on the bolsters laterally between the centers and ends thereof, spring members disposed between the active and static bolsters in selected ones of the spring retaining means in predetermined positions which members are effectively adapted to reduce a car body natural roll frequency to stabilize the car body on the truck.
2. The car truck of claim 1 in which the opposed flanges of the static bolster have a greater vertical extent at the center than at the ends thereof.
3. The car truck of claim 1 in which stop means are provided in the side frame columns above the static bolster.
4. The car truck of claim 1 in which the bottom surface of the static bolster, that contacts the side frame tension member, contains a convexed arcuate surface having as its center an axis normal to the vertical plane of the side frame.
5. The car truck of claim 1 in which there is sufficient clearance between the upwardly extending flanges of the static bolster and the side frame columns to allow rocking.
6. The car truck of claim 1 in which the lower supported surface of the active bolster is normally parallel to the spring seat surface of the static bolster.