Monorail vehicle apparatus with trucks designed to accommodate movement along curved rail sections

Abstract

The present invention teaches a monorail vehicle apparatus and method for controlling roll attitude, lateral location, and loading of a monorail vehicle traveling on a non-featured rail exhibiting substantial profile variation by the placement of the vehicle's center of gravity and without the use of additional mechanisms such as springs or suspensions. The design is especially well adapted for travelling along curves by using at least two trucks connected by a linkage mechanism.

Description

RELATED APPLICATIONS[0001]This application is a Continuation-in-Part of U.S. patent application Ser. No. 13 / 724,417 by John S. Camp et al., filed on Dec. 21, 2012 and incorporated herein in its entirety.FIELD OF THE INVENTION[0002]This application is related to monorail vehicle apparatus and methods for constraining the roll attitude, lateral location and loading of such monorail vehicle, and more precisely still, to constraining the roll attitude, lateral location and loading through appropriate placement of the center of gravity of the monorail vehicle at a certain offset to the non-featured rail, as well as appropriate trucks and assemblies that interface with the non-featured rail to accommodate movement on curved sections of the non-featured rail.BACKGROUND ART[0003]Many types of cars, carts, vehicles and trolleys are supported on bogies or trucks that are designed for engagement with and travel on non-featured rails. A subset of such vehicles constrained to travel on rails inc...

AI Technical Summary

Benefits of technology

[0017]In view of the above shortcomings of the prior art, it is an object of the present invention to provide for monorail vehicle apparatus and methods that enable deployment of low-cost, low-quality, off-the-shelf (stock) rails including those with rectangular or square cross-sections and substantial profile variation while retaining the advantages of constant contact force on the bogie's roll-control wheels as well as accurate constraint of roll attitude and lateral translation.

[0019]It is still another object of the invention to provide for monorail vehicle bogies with fewer wheels than typically required in mechanisms with opposing springs, and to generate forces that control roll attitude and loading of the monorail vehicle by means of a judicious placement of its center of gravity.

[0023]The bogie has a drive mechanism for moving or displacing the monorail vehicle along the non-featured rail in either direction. The bogie also has at least two trucks that are connected by a connector mechanism. Each truck has a first assembly for engaging the non-featured rail on a first rail surface and a second assembly for engaging the non-featured rail on a second rail surface. The bogie resists the roll moment Nr with the two assemblies of each truck that engage the non-featured rail on the two rail surfaces. In accordance with the invention, these first and second rail surfaces are chosen such that a pair of surface normal reaction forces is produced on the trucks and subsequently on the bogie through the connector mechanism that connects the trucks, resulting in the roll attitude, lateral translation and loading of the monorail vehicle being constrained by the placement of the center of gravity. This approach supports accurate alignment of the bogie and therefore of the monorail vehicle.

[0025]Special attention is paid to the connector mechanism connecting the trucks in the bogie. The connector mechanism can consist of a rigid plate, such as a metal plate, and further include a linkage mechanism that joins each truck to the connector mechanism. The linkage mechanism allows for certain freedom of movement of each truck around the connector mechanism in order to better tolerate curves and profile variations in the rail, as well as imperfections on the rail surface.

Problems solved by technology

The design and manner of engagement between carriages or bogies of monorail vehicles and the non-featured rail or monorail presents a number of challenges specific to these vehicles.

Roll, the rotation about the longitudinal direction or about the rail is more challenging to constrain.

However, Kaufman's monorail trolley does not teach to control forces on lateral wheels to control the roll axis and roll attitude and it does not support accurate trolley localization on a non-featured rail.

Furthermore, this design is not appropriate for rail that has have long unsupported spans that place restrictions on minimum torsional stiffness, minimum lateral bending stiffness, minimum vertical bending stiffness and maximum material stress.

In fact, a transportation system as taught by Sullivan incurs high torsional forces that would not be appropriate in situations deploying rails having substantially varying profiles (e.g., low-grade stock rails whose cross-sections exhibit substantial profile variation) and rail that contemporaneously have long unsupported spans that place restrictions on minimum torsional stiffness, minimum bending stiffness and maximum material stress.

Again, although Timan's solutions use uniform cross-section rails and address the roll of the monorail bogie, they are not appropriate for rails whose cross-sections exhibit substantial profile variation and require a vehicle with a multitude of mechanisms for controlling the monorail bogie with respect to the rail.

Unfortunately, deployment of large opposing springs to clamp the rail is undesirable in many applications.

Such mechanisms involve many parts, are unreliable and contribute to vehicle cost and mass.

Further, in the case in which the apparatus must use an unsupported guide rail that is as small and inexpensive as possible and the vehicle of the apparatus must be accurately located, the prior art does not produce a satisfactory solution.

Further, as the rail is unsupported over long lengths, such a rail would be additionally constrained by limitations on minimum torsional stiffness, minimum lateral bending stiffness, minimum vertical bending stiffness and maximum material stress.

These additional requirements mean that the featured cross-sections as taught in the first general approach in the prior art are not viable for unsupported spans.

Thus, the prior art struggles to deliver accurate location of a vehicle under these constraints.

A high preload creates high rolling resistance, increases wheel wear, and increases the amount of deflection seen by the wheel, making this solution undesirable.

In other words, a suspension system compatible with low-cost rail using opposing springs would either inaccurately locate to the rail or require excessive preloads to ensure contact during vehicle travel.

Thus, prior art approaches exhibit many limitations that render them inappropriate for controlling roll in monorail vehicles that are deployed on low-cost, low-quality, non-featured stock rails with substantially varying profiles and requiring long unsupported spans.

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