Articulated Railway Truck

Abstract

Two articulated railway truck assemblies for supporting and steering a railway vehicle, each comprising a main truck pivotally connected to the railway vehicle and two sub-trucks pivotally connected to the main truck, at least one of the sub-trucks also being pivotally connected to the railway vehicle at a particular point whose location is determined by the ratio of the truck assembly's wheel base to the distance between truck assemblies.

Parent Case Text

This application is a continuation of my copending application Ser. No. 882,359, filed Dec. 15, 1967, now abandoned, which was a continuation of my application Ser. No. 680,257, filed Nov. 2, 1967, now abandoned.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to railway trucks and more particularly to railway trucks having a plurality of axles so mounted as to allow each to take a position on a curved track substantially radial to the curve.

The axles of wheels mounted on the type of railway truck normally used always remain substantially parallel. Since the axles do not move radial to a curved track on which the railway vehicle may be traveling, the flanges of their wheels strike the curved rails at an angle. This is a main cause of the noise which occurs when ordinary railway trains travel on a curved track. Resulting wear of the wheel flanges causes a high level of noise when the train is traveling on a straight track. With a rapid transit system in a heavily populated area, this noise is particularly objectionable.

Since the usual trucks do not steer themselves, wheels having conical treads and rails having rounded tops are used to assist the train around curves. However, a tendency to nose, i.e., an objectional lateral oscillation of the train at high speed, may result from the use of these features.

Because of the high stresses produced in an ordinary railway truck having stationary axles when rounding a curve, the use of sound and vibration absorbing resilient material is limited.

To overcome these problems, articulating railway trucks have previously been designed for the purpose of allowing the wheel axles to become positioned on a curved track substantially radial to the curve. In particular, U.S. Pat. No. 243,797 issued to W. Robinson on July 5, 1881 discloses two railway trucks supporting a railway car, each having a main truck pivotally joined at its center to a railway car, and a pair of sub-trucks pivotally joined to the main truck. A pair of wheels is rotatably mounted on each sub-truck by a single axle, and the pivotal connections between the main truck and sub-trucks lie over these axles. One or both of these sub-trucks are also pivotally connected to the railway car. However, the Robinson patent neither discloses nor appreciates the fact that a pivot connecting a sub-truck with the railway car must be located at a particular point determined by the truck's wheel base and the distance between trucks. A pivot otherwise located will prevent rather than assist the axles in turning radial to a curve.

SUMMARY OF THE INVENTION

It has been discovered that the axial lines of wheels in two railway truck assemblies which support a railway vehicle and each of which comprises a main truck pivotally connected to the railway vehicle and two sub-trucks pivotally connected to the main truck, can be positioned substantially radial to a curved track on which the railway vehicle is located by pivotally connecting at least one of the sub-trucks in each truck assembly to the railway vehicle at a particular point, whose location is determined by the ratio of the truck assembly's wheel base to the distance between truck assemblies.

With the truck assemblies steering the train, flat wheel treads and rail tops may be used. This allows higher load ratings on the wheels and longer wheel and rail life, as well as assisting in the avoidance of nosing.

Sound and vibration absorbing material can be used more extensively in this truck assembly thin in the usual railway truck, because its articulation avoids many of the stresses produced when rounding curves.

Since the pivotal connections between the railway vehicle and main truck, and between the main truck and subtrucks, need not be positioned at any definite location, one designing an embodiment of this truck assembly has a great deal of flexibility. The pivotal connections between the main truck and sub-trucks need not be over the axles, thereby allowing this area to be utilized for brakes or other apparatus. Where the weight of a locomotive is transferred to the main truck at the pivotal connection between the two, this connection may be placed near a powered pair of wheels in order to increase traction between those wheels and the rails.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic plan view of a railway car on a curved track and supported by two truck assemblies embodying the present invention.

FIG. 2 is an enlarged fragmentary schematic plan view related to one of the truck assemblies shown in FIG. 1.

FIG. 3 is a plan view of one form of truck assembly in accordance with the invention.

FIG. 4 is a longitudinal section taken along line 4--4 of FIG. 3.

FIG. 5 is a transverse section taken along line 5--5 of FIG. 4.

FIG. 6 is a transverse section taken along line 6--6 of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2 are used in deriving the equation defining the invention. FIG. 1 schematically represents a railway car 1 supported by two truck assemblies on a track 2 of constant curvature. Body bolsters 3 connected together by member 4 transmit the load of the railway car to the truck assemblies. The term "railway vehicle" will be used herein and shall refer to a railway car or locomotive, together with any other devices which remain fixed in a horizontal plane with respect to the railway car or locomotive such as body bolsters 3.

As illustrated in FIGS. 1 and 2, each truck assembly comprises a main truck 5 and two sub-trucks, 6 and 7. A pair of axially aligned flange wheels 8 having axles within an axle housing 9 and radial to the curve are rotatably mounted on each sub-truck. The main truck is pivotally connected to the railway car at point X which is not shown centrally placed in order to illustrate the broad application of the equation defining the invention. However, the X points on the truck assemblies must be located equidistant from a point which is intermediate points midway between the axial lines of the two pair of wheels in each truck assembly, when the railway vehicle is on a straight track or one having a constant degree of curvature. The sub-trucks are pivotally connected to the main truck at Y and Y' which need not be located above the axial lines of the wheels; however, Y and Y' need be placed equidistant from a point intermediate the axial lines of the wheels when these axial lines are parallel, and on a vertical longitudinal plane passing through point X and perpendicular to the parallel axial lines.

Referring to FIG. 2, extensions of sub-trucks 6 and 7 may be pivotally connected to the railway vehicle at points Z and Z' respectively, which lie on lines passing through the Y points and perpendicular to the axial lines of the wheels. Since the axial lines of the wheels are initially positioned radial, pivotal connections at Z and Z' will of necessity fix the axial lines of the wheels in a radial position.

In deriving an equation by which points Z and Z' may be located as a function of each truck assembly's wheel base and the distance between truck assemblies, the letters shown in FIGS. 1 and 2 represent the following:

A = one half the angle formed by two radial lines, each line bisecting the angle formed by the two radial axial lines of the two pair of wheels in each truck assembly;

B = the angle formed by one of said bisecting radial lines and an adjacent axial line;

r = radius of the arc concentric with the rails of the curved track on which the railway vehicle is located, and passing through the intersections of said bisecting radial lines with a line going through the X points;

a = horizontal measurement of the truck assembly's wheel base;

b = horizontal distance between truck assemblies measured from points located at the intersections of said bisecting radial lines with said arc, these points also being located intermediate, or approximately intermediate, the axial lines of the two pair of wheels in each truck assembly when these axial lines are parallel;

c, d, e and c', d', e' are the distances shown in FIG. 2.

Since only relatively small angles are involved, it may be assumed with sufficient accuracy that angles A and B equal their sines. Therefore; A = sine A = 1/2b/r = b/2r, B = sine B = 1/2a/r = a/2r, and B/A = a/b. Small angles also closely approximate their tangents, therefore; A = tan A = e/c or e'/c'; B = tan B = e/d or e'/d', and B/A = c/d = c'/d' = a/b.

Since, with the approximations made, the radius of the curve does not affect the location of point Z or Z', pivoted connection at these points will be effective irrespective of the degree of curvature of the track. Additionally, these points can be located by the c and d, or c' and d' measurements when the railway vehicle is on a straight track.

By pivotally connecting the railway vehicle and subtracks at these Z points, an interdependent linking arrangement exists among the railway vehicle, the main truck and sub-trucks, whereby the axial lines of wheels mounted on the sub-trucks are placed radial to a curve which the railway vehicle is rounding. When the flanges of the wheels strike a curved rail, the main truck will pivot with respect to the railway vehicle. This causes the sub-trucks pivotally connected to the main truck and, at a point located by the equation, to the railway vehicle to pivot and place the axial lines of their wheels radial to the curve. Of course, contemporaneous with the above action initiated by the main truck pivoting with respect to the railway vehicle, the axial lines of the wheel mounted on the sub-trucks will be positioned somewhat radial to the curve by the force of the curved rail on the wheel flanges. This action will compliment the prior action and assist in placing the axial lines radial to the curve.

However, since extensions of the sub-trucks will overlap if they both are pivotally connected to the railway vehicle at their respective Z points, this arrangement may not be a practical design. The same purpose may be achieved by connecting only one of the sub-trucks with the railway vehicle at a Z point while linking the sub-trucks together such that rotation of one causes the other to rotate an equal amount in the opposite direction.

FIG. 3 shows a preferred embodiment of the truck assembly on a straight track 10. A body bolster 3 transmits the load of the railway car from springs 11 to the truck assembly and is horizontally fixed with respect to the railway car, thereby being included in the term "railway vehicle." Member 4 connects the body bolster shown to another body bolster located above a similar truck assembly disposed toward the opposite end of the railway vehicle. The main truck comprises a substantially horizontal top 12 and two downwardly extending sides 13. Two apertures 14 are located within the top of the main truck. A main pivotal connection 15, centrally located at point X, joins the top of the main truck to the railway vehicle. Interposed between the downwardly extending sides of the main truck are two sub-trucks disposed toward opposite ends of the main truck. The sub-trucks like the main truck have substantially horizontal tops 16a and 16b, and downwardly extending sides, 17a and 17b; the tops of the sub-trucks at theier adjacent ends are narrow. Each sub-truck rotatably mounts a pair of axially aligned flanged wheels 8 whose axles 5a are within axle housings 9.

As shown in FIGS. 3, 4 and 5, resilient spacers 18 comprised of slightly resilient plastic pads are interposed between the sides of the main truck and those of the sub-truck. Stiff steel springs may be used as resilient spacers. Each sub-truck has a pair of these spacers placed at corresponding locations on its opposite sides. These spacers allow the sub-trucks to rotate with respect to the main truck about predetermined pivot points, Y and Y', corresponding to the Y and Y' pivots shown in FIGS. 1 and 2. The flexibility of the resilient spacers also permit a slight amount of longitudinal movement between the sub-trucks and main truck, thereby allowing rotation of the sub-trucks with respect to the main truck and railway vehicle without binding. Although in the truck assembly illustrated, resilient spacers provide a flexible connection between the main truck and each sub-truck, other embodiments of my invention may avoid binding within the truck assembly by providing flexibility at another connection or other connections joining one or both sub-trucks.

Also illustrated in FIGS. 3, 4 and 5 are bearing members 19, a pair of which is interposed between the top of each sub-truck and the main truck. The bearing members transmit the load from the main truck to the sub-trucks but allow relative movement between them.

FIGS. 4 and 6 show the sub-trucks linked together at adjacent ends of their tops by a pivotal connection 20. Pivotal connection 20 is placed midway between the pivot points Y and Y' such that rotation of one of the sub-trucks will effect an equal but opposite rotation of the other. By overlapping adjacent ends, the opposite torques produced on the sub-trucks by braking counteract each other.

FIGS. 4 and 6 also disclose the preferred means of joining the railway vehicle with one of the sub-trucks such that they pivot with respect to each other about a particular point, Z. Pivotal connection 21 joins the narrow end of one of the sub-trucks' tops 16a to plate 22 which is rigidly suspended from the railway vehicle. Two pins 23 secured to the railway vehicle extend downwardly through the apertures 14 in the top 12 of the main truck, pass on both sides of the narrow adjacent ends of the sub-trucks' tops and hold plate 22 rigid with respect to the railway vehicle.

Pivotal connection 21 is at a particular point, point Z, which is located on a vertical longitudinal plane passing through main pivotal connection 15 at point X and perpendicular to the parallel axial lines of wheels 8, and at a location such that the equation a/b = c/d is satisfied; where

a = horizontal measurement of the truck assembly's wheel base;

b = horizontal distance between the two truck assemblies measured from points intermediate the axial lines of the two pairs of wheels in each truck assembly;

c = horizontal distance between the particular point Z and the main pivotal connection 15 at point X;

d = horizontal distance between the particular point Z and point Y which is intermediate the pair of spacers located on the sides 17a of the sub-truck joined to plate 22 by pivotal connection 21.

While the truck assembly shown has two pair of wheels, my invention may also be used with truck assemblies possessing three pair. In which case, the axial line of the center pair of wheels in the truck assembly need not be rotatable with respect to the main truck to assume a radial position.

Claims

1. Supporting and steering means for a railway vehicle, said means comprising two articulated truck assemblies disposed toward opposite ends of said railway vehicle, each of said truck assemblies comprising:

a. a main truck

b. two sub-trucks disposed toward opposite ends of said main truck;

c. two pair of axially aligned flanged wheels, each pair rotatably mounted on one of said sub-trucks;

d. a main pivotal connection joining said main truck with said railway vehicle, the main pivotal connection of the two truck assemblies located equidistant from a point intermediate points midway between the axial lines of the two pair of wheels in each truck assembly when the railway vehicle is on a straight track;

e. two connecting means, each joining one of said sub-trucks with said main truck, said connecting means allowing said sub-trucks to rotate with respect to said main truck about pivot points located, when the axial lines of said wheels are parallel, on a vertical longitudinal plane passing through said main pivotal connection and perpendicular to said parallel axis lines, said pivot points also located equidistant from a point intermediate said axial lines;

f. means pivotally connecting said sub-trucks, whereby rotation of one of said sub-trucks about its pivot point causes the other sub-truck to rotate an equal amount in the opposite direction about its pivot point;

g. means pivotally connecting said railway vehicle to one of said sub-trucks, said means not in contact with said main truck and pivotally joining said sub-truck at a particular point, said particular point located, when the axial lines of said wheels are parallel, on said vertical longitudinal plane, at a location such that the equation a/b = c/d is satisfied; where:

a = horizontal measurement of the truck assembly's wheel base;

b = horizontal distance between the two truck assemblies measured from points intermediate the axial lines of the two pair of wheels in each truck assembly;

c = horizontal distance between said particular point and said main pivotal connection;

d = horizontal distance between said particular point and the pivot point on the sub-truck joined to said railway vehicle by said pivotally connecting means;

h. at least one flexible means integral with at least one of said connections joining one of said sub-trucks to said main truck, said means allowing controlled movement of said connection, thereby permitting rotation of said sub-trucks with respect to said main truck and said

2. Supporting and steering means for a railway vehicle, said means comprising two articulated truck assemblies disposed toward opposite ends of said railway vehicle, each of said truck assemblies comprising:

a. a main truck;

b. two sub-trucks disposed toward opposite ends of of said main truck;

c. two pair of axially aligned flanged wheels, each pair rotatably mounted on one of said sub-trucks;

d. a main pivotal connection joining said main truck with said railway vehicle, the main pivotal connection of the two truck assemblies located equidistant from a point intermediate points midway between the axial lines of the two pair of wheels in each truck assembly when the railway vehicle is on a straight track;

e. two connecting means, each joining one of said sub-trucks with said main truck, said connecting means allowing said sub-trucks to rotate with respect to said main truck about pivot points located, when the axial lines of said wheels are parallel, on a vertical longitudinal plane passing through said main pivotal connection and perpendicular to said parallel axis lines, said pivot points also located equidistant from a point intermediate said axial lines;

f. two means pivotally connecting said sub-trucks to said railway vehicle, each of said means not in contact with said main truck and pivotally joining one of said sub-trucks at a particular point, each of said particular points being located when the axial lines of said wheels are parallel on said vertical longitudinal plane, at a location such that the equation a/b = c/d is satisfied where:

a = horizontal measurement of the truck assembly's wheel base;

b = horizontal distance between the two truck assemblies measured from points intermediate the axial lines of the two pair of wheels in each truck assembly;

c = horizontal distance between said particular point and said main pivotal connection;

d = horizontal distance between said particular point and the pivot point on the sub-truck being joined to said railway vehicle at said particular point;

g. a plurality of flexible means, at least one of which is integral with at least one of said connections joining each sub-truck to said main truck, said means allowing controlled movement of said connection, thereby permitting rotation of said sub-trucks with respect to said main truck and

3. Supporting and steering means for a railway vehicle, said means comprising two articulated truck assemblies disposed toward opposite ends of said railway vehicle, each of said truck assemblies comprising:

a. a main truck having downwardly projecting sides and a top having an aperture therein;

b. two sub-trucks having sides, located between the sides of said main truck and disposed toward opposite ends of said main truck;

c. two pair of axially aligned flanged wheels, each pair rotatably mounted on one of said sub-trucks;

d. a main pivotal connection joining said main truck with said railroad vehicle, the main pivotal connection of the two truck assemblies located equidistant from a point intermediate points midway between the axial lines of the two pair of wheels in each truck assembly when the railway vehicle is on a straight track;

e. a pivotal connection joining said sub-trucks to each other and located, when the axial line of said wheels are parallel, equidistant from said parallel axial lines and on a vertical longitudinal plane passing through said main pivotal connection and perpendicular to said parallel axial line;

f. two pair of resilient spacers, the spacers of each pair being located on corresponding opposite sides of one of said sub-trucks between the sides thereof and the sides of said main truck, said pairs of spacers being equidistant from the pivotal connection joining said sub-trucks to each other;

g. connecting means secured to said railway vehicle and projecting downwardly through the aperture in the top of said main truck with clearance relative to said main truck, said means pivotally connecting said railway vehicle to one of said sub-trucks at a point displaced

4. The supporting and steering means of claim 1 in which said connecting means pivotally connects the railway vehicle and one of said sub-trucks at a particular point, said particular point located when the axial lines of said wheels are parallel on said vertical longitudinal plane, at a location such that the equation a/b = c/d is satisfied; where:

a = horizontal measurement of the truck assembly's wheel base;

b = horizontal distance between the two truck assemblies measured from points intermediate the axial lines of the two pairs of wheels in each truck assembly;

c = horizontal distance between said particular point and said main pivotal connection;

d = horizontal distance between said particular point and a point intermediate the pair of spacers located on the sides of the sub-truck

5. Railway vehicle running-gear comprising at least two rotatable load-carrying axles, movable to different relative angularities in a horizontal plane, each of said two axles having a pair of spaced-apart flanged wheels mounted normally fixedly thereon to rotate therewith and adapted to transmit weight from the axle to a pair of rails, a pair of frame structures, one for each of said two axles, each frame structure having means for rotatively mounting its associated axle, and having, in relation to its associated axle, a substantially fixed angularity in a horizontal plane, and each frame structure extending from its associated axle to a common point substantially midway between said two axles and substantially equi-spaced from the two wheels of the associated axle, a pivotal connection between said structures having a substantially vertical pivot axis at said point, and means providing for limited bodily lateral

6. A railway vehicle truck assembly comprising at least two rotatable load-carrying axles, movable to different relative angularities in a horizontal plane, each of said two axles having a pair of spaced-apart flanged wheels mounted normally fixedly thereon to rotate therewith and adapted to transmit weight from the axle to a pair of rails, a main truck frame having a pivot for articulation with the vehicle, a pair of sub-frame structures, one for each of said two axles, each sub-frame structure having means for rotatively mounting its associated axle, and having, in relation to its associated axle, a substantially fixed angularity in a horizontal plane, and each sub-frame structure extending from its associated axle to a common point substantially midway between said two axles and substantially equi-spaced from the two wheels of the associated axle, a pivotal connection between said sub-frame structures having a substantially vertical pivot axis at said point, and means resistively permitting lateral motion between the sub-frame structures and the main truck frame.