Railway rolling stock – Locomotives – With land engaging wheel
Reexamination Certificate
1999-11-17
2001-10-30
Le, Mark T. (Department: 3617)
Railway rolling stock
Locomotives
With land engaging wheel
C105S215200, C104S243000
Reexamination Certificate
active
06308640
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This application is co-pending with an application entitled “Apparatus and Method for Steering a Guideway Vehicle” filed as a provisional application on Mar. 12, 1999 simultaneously with the subject provisional application and having the same inventorship.
This invention relates to steering mechanisms for vehicles. More particularly, it relates to an apparatus for steering a vehicle to follow a track or guideway.
2. Description of the Related Art
Various types of on-track and off-track vehicles are currently used for mass transportation. Frequently, it is desirable for the same vehicle to be available for use on a track following a guideway (on-track) as well as on a roadway without the assistance of a guideway (off-track). This is especially useful for a vehicle that must be removed from a guideway and moved to another location for repair or maintenance. The term “guideway” is used herein to describe a roadway surface with a guide rail for steering a vehicle along a predetermined course.
Typically, such a vehicle follows a guide rail embedded below the roadway surface of the guideway and, as a result, certain elements of the vehicle steering mechanism, such as the guide wheels extending from the vehicle undercarriage which track the guide rail, protrude below the roadway surface of the guideway. This arrangement is not acceptable for off-track use because the roadway would interfere with the steering mechanism.
Ordinarily, a vehicle adapted for use both on-track and off-track employs a conventional design using pneumatic tires to operate on any substantially flat surface. Accordingly, when operated as an on-track vehicle, the guideway is substantially flat and a guide rail is mounted on the guideway parallel to the roadway surface for guiding the vehicle along a predetermined course.
U.S. Pat. No. 3,796,165 describes a guide following steering apparatus in which all of the components of the steering apparatus are above the roadway surface of the guideway. The apparatus uses guide followers protruding from the front and the rear of the vehicle. Each guide follower is associated with two steerable drive tires on each of two axles and the two guide followers are connected together with steering linkages. However, the vehicle is bi-directional and only the leading guide follower, whichever one it may be, controls the steering for wheels on both axles. In certain instances, such a design is undesirable because the protruding guide followers diminish the ride quality of the vehicle.
U.S. Pat. No. 3,515,405 describes an axle suspension system for transit vehicles utilizing a central guidance system comprised of four guide wheels attached to a guide frame to follow the direction of a guide rail. In the process, one axle on the transit vehicle orients to follow that guide rail. At least two axles are associated with a separate guidance apparatus and there is no interconnection between the two apparatuses. However, the arrangement disclosed in this patent illustrates a guide rail below the roadway surface of the guideway which makes off-track use of the vehicle impossible. Furthermore, this arrangement pivots the entire axle such that the wheels on both sides of the axle rotate as a unit. This requires the entire axle, axle housing and associate frame to be rotated when it is only necessary to turn the wheels of the axle.
It is an object of this invention to provide a guidance apparatus capable of following a guide rail located on a guideway at or above the roadway surface of the guideway using a central guidance platform and steerable axles to alleviate the need to turn the entire axle and axle housing when the vehicle must turn.
SUMMARY OF THE INVENTION
The invention is directed to a steering apparatus for a vehicle adapted to travel on a guideway having a central guide rail parallel to the desired course of the vehicle. The vehicle has a vehicle body with front and rear wheel assemblies. At least one wheel assembly comprises a support frame attached to the vehicle body and a stationary axle housing mounted to the support frame. The axle housing contains an axle having an axle axis. A first steerable drive tire is mounted at one end of the axle and a second steerable drive tire is mounted at the other end of the axle. A guide frame is pivotally mounted to the axle housing about a vertical guide frame axis. Four guide wheels are pivotally mounted upon the guide frame to pivot the guide frame and turn the steerable drive tire.
The guide frame may be pivotally mounted to the axle housing through a ring bearing connecting the two frames.
The steering apparatus may include a steering linkage extending from the guide frame to the first steerable drive tire hub whereby when the guide frame rotates relative to the axle housing, the first steerable drive tire hub also rotates relative to the axle housing. A similar geometry may be utilized for the second steerable drive tire hub or, in the alternative, a drag link may connect the second steerable drive tire hub to the first steerable drive tire hub to impart steering to the second drive tire hub.
REFERENCES:
patent: 2468158 (1949-04-01), Bartholomew
patent: 3077165 (1963-02-01), Vittorelli
patent: 3312180 (1967-04-01), Mueller
patent: 3515405 (1970-06-01), Segar
patent: 3796165 (1974-03-01), Goode
patent: 3858523 (1975-01-01), Allsup, Jr.
patent: 3921466 (1975-11-01), Allsup, Jr.
patent: 4089272 (1978-05-01), Schmitz
patent: 4223611 (1980-09-01), Dawson et al.
patent: 4232611 (1980-11-01), Uozumi
patent: 4299172 (1981-11-01), Dawson
patent: 4454819 (1984-06-01), Cuylitz et al.
patent: 5174219 (1992-12-01), Streiff
Cooper William K.
Krause Ralf
Schwalm Jeffrey J.
Stubelt Holger
Weule Christian
Daimler-Chrysler AG
Le Mark T.
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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