Patent Application
20140116284
This invention claims the benefit of priority to Australian Provisional Patent Application 2012904776 filed Nov. 1, 2012, the entire disclosure of which is incorporated by reference.
Various aspects of the invention relate to drive mechanisms and vehicles, and to components therefor.
The invention will be described with respect to an articulated boom lift for rail applications, although various embodiments of the invention may be suited to other applications.
An articulated boom lift is a vehicle 1 including a boom 2 carrying a work platform 3. A work platform is a platform on which a worker may stand. The boom 2 is articulated to allow the work platform 3 to be moved about within its service envelope 4. The boom 2 is pivotally mounted to a chassis 5 to permit rotation about vertical axis 6 so that a worker carried by the platform 3 can access and work on structures in the vicinity of the vehicle 1.
Other forms of elevatable platforms exist. By way of example, the boom 2 may be replaced by a scissor-lift mechanism.
Vehicles carrying elevatable platforms are useful for accomplishing overhead tasks such as trimming trees and repairing overhead wires. Various existing vehicles include road-engaging wheels 7 for running along a roadway to position the vehicle 1.
“Roadway” as used herein refers to a more or less planar surface along which a vehicle may run. The roadway surface may bituminous or cementitious or, for example, unsealed gravel.
Railways frequently require overhead maintenance, particularly those railways in which the trains are powered via overhead power lines. For the purpose of this maintenance, various vehicles having elevatable work platforms and rail-engaging wheel arrangements have been proposed.
It is not admitted that any of the information in this patent specification is common general knowledge, or that the person skilled in the art could be reasonably expected to ascertain or understand it, regard it as relevant or combine it in any way at the priority date.
The present inventor has recognised that it would be useful to provide a vehicle adapted to run along a roadway in one mode of operation, and to run along rails in another mode of operation. Also, it would be useful to provide a vehicle which may run along rails of differing gauges. “Gauge” as used herein refers to the lateral spacing of the rails of a railway. A drive mechanism is disclosed, various embodiments of which are suited to a gauge-adjustable vehicle, whilst other embodiments of the drive mechanism may suit applications unrelated to vehicles.
One aspect of the invention provides a drive mechanism including
a traction portion encircling and rotatable about an axis;
a drive-receiving portion encircling the axis and fixed to rotate with the traction portion; and
a driven portion for engaging the drive-receiving portion to drive the traction portion to rotate;
wherein the traction portion is moveable relative to the driven portion to a plurality of positions, relative to the driven portion, along the axis; and
at least one of the drive-receiving portion and the driven portion has a length along which it is engageable by the other of the drive-receiving portion and the driven portion such that the drive-receiving portion and the driven portion co-operate to drive the traction portion at its plurality of positions, relative to the driven portion, along the axis.
The traction portion is preferably the periphery of a wheel for engaging a rail. The driven portion is preferably the periphery of a wheel for engaging a roadway. The drive-receiving portion is preferably the periphery of a friction drum.
Another aspect of the invention provides a vehicle including the drive mechanism. The vehicle preferably includes a vehicle body carrying a retro-fit module wherein the vehicle body carries the driven portion; and the module includes the traction portion and the drive-receiving portion.
Preferably the vehicle includes a control system including a user interface from which a user can control locomotion of the vehicle, wherein the control system has at least two modes and is configured to
when in a first of the modes, rotate the driven portion in a first direction in response to a user input; and
when in a second of the modes, rotate the driven portion in a second direction in response to the same user input.
Another aspect of the invention provides a module attached or attachable to a vehicle,
the vehicle having wheels for running along a roadway,
the module including a gauge adjustable arrangement of wheels for engaging and running along rails.
Preferably the vehicle includes a drive system for driving at least on the wheels for running along the roadway; and the arrangement of wheels includes at least one wheel driven by power drawn from the drive system. Most preferably the power is mechanically drawn.
Preferably a friction drum is fixed to rotate with the at least one wheel and arranged to be driven by at least one of the wheels for running along a roadway.
Another aspect of the invention provides a vehicle including the module.
Preferably the vehicle includes an elevatable work platform, and most preferably a or the user interface from which a user can control locomotion of the vehicle is associated or associable with the work platform for controlling from the work platform locomotion of the vehicle.
Another aspect of the invention provides a vehicle, for travelling along rails, including
an arrangement of wheels for engaging the rails;
an elevatable work platform; and
a user interface associated with the work platform for controlling from the work platform locomotion of the vehicle;
wherein the arrangement of wheels is gauge adjustable.
Further objects and advantages of this invention will be apparent from the following detailed description of the presently preferred embodiments which are illustrated schematically in the accompanying drawings.
The figures illustrate various exemplary features.
a is an elevation of an articulated boom lift.
b is a plan view of an articulated boom lift.
Before explaining the disclosed embodiments of the present invention in detail it is to be understood that the invention is not limited in its applications to the details of the particular arrangements shown since the invention is capable of other embodiments. Also, the terminology used herein is for the purpose of description and not of limitation.
Vehicle 10 includes four ground-engaging wheels 16. Each ground-engaging wheel 16 includes a metallic rim wrapped in a rubber tyre. The vehicle 10 further includes a drive system including a pump driving pressurised fluid to a respective hydraulic motor associated with each wheel 16. The drive system is configured to failsafe such that hydraulic pressure is required for the hydraulic motors, and their wheels, to rotate. In the event of a leak in the hydraulic system, the wheels are braked such that they do not rotate and the vehicle 10 does not run away.
Each module 14 includes a pair of rail-engaging wheels 18 mounted to rotate about a common axis A. Each wheel 18 has a nominal diameter of 350 mm and a profile to ANZR1 modified for use with an excavator. The wheels 18 are formed of 4140 to AS1444-2007-4140 and flame hardened for increased wear life.
Each wheel 18 includes a more or less cylindrical outer periphery (concentric to the axis A) forming a traction portion 18a for bearing on the top surface of a respective rail to support and horizontally drive the vehicle 10. Each wheel 18 further includes an annular flange 18b projecting radially outwards from an inboard side of the wheel. The flange 18b serves to engage an inner side of that wheel's rail so that the vehicle 10 remains laterally aligned with the rails.
Each wheel 18a carries a respective friction drum 20 on its outboard side. Each friction drum 20 has a cylindrical outer periphery concentrically aligned with the axis A, and so also to the wheel 18. This cylindrical periphery constitutes a drive-receiving portion 20a. The drive-receiving portion 20a is suitably textured to receive drive, e.g. with axially extending grooves as illustrated.
Turning to
Desirably, this exemplary module is a retro-fit unit, i.e. it is built for attachment to a pre-existing vehicle rather than being built as an integral part of the vehicle. Accordingly the modules can be sold separately from vehicles to upgrade existing road-going vehicles.
The swing arm assembly 24 includes a pair of swing arms 24a pivotally connected to the fixed portion 22. Each swing arm 24a includes parallel plates spaced to embrace a portion of a respective one of the plates 22a in the manner of a yoke.
The swing arms 24 carry a square tubular section 24b at a distance from their common pivot axis. The tubular section 24b extends horizontally across the vehicle 10.
Each wheel 18 is journalled to a respective stub axle (not shown) having a square cross-section dimensioned for sliding receipt within the tubular portion 24b.
Each wheel 18 and stub axle subassembly has a respective hydraulic ram 26 acting between that stub axle and the tubular member 24b to horizontally drive the subassembly to move the wheel 18 along the axis A to suit a desired gauge.
In the example of
A respective hydraulic ram 28 acts between each plate 22a and its swing arm 24a to pivotally raise and lower the wheels 18 (relative to the ground-engaging wheels 16) to suit roadway and railway operation respectively.
For the sake of illustration, the left hand side of
With reference to the left hand side of
The right hand side of
The wheels 16 bear on the friction drums 20 to rotationally drive the drums and in turn the wheels 18. The wheels 16, or more specifically their outer peripheries 16a, constitute driven portions. The drive mechanism of the original vehicle 12 through its standard drive train, including the failsafe hydraulic motors, may thus drive the wheels 18 to drive the vehicle 10 along the rails 30.
Following this exemplary approach, the expense of a drive system dedicated to the rail wheels is avoided and the advantages of the failsafe operation are retained.
Typically the wheels 18, and the drums carried thereby, are moved to their desired lateral positions whilst the swing arm 24 is in its raised position. The friction drums 20 are about twice as long as they are wide. The cross-section of each drum 20 is in substance uniform along the drum's length whereby each wheel 16 may engage its drum at an infinity of selectable positions along its length. For the avoidance of doubt, this infinitely variable arrangement fits the description of “a plurality of positions” as those words are used herein. Of course it is also contemplated that in other variants the drive-receiving portions may co-operate with the driven portions at separate discrete axial positions; e.g. the friction drum may be replaced by discrete parallel gears.
A wide range of variants of the above mechanism is contemplated. By way of example, the elongate friction drums may be replaced by narrow drive-receiving wheels acting on elongate friction drums fixed relative to the ground-engaging wheels. The elongate friction drums fixed relative to the ground engaging wheels would preferably run parallel to the axis A. Indeed in some variants the rail-engaging wheels may engage directly with the ground-engaging wheels, e.g. the traction portions and the drive-receiving portions could be one and the same. In yet another variant, the friction drums 20 could be driven by a belt.
In operation the rail-engaging wheels 18 rotate in the opposite direction to the ground-engaging wheels 16. Thus preferred variants of the invention incorporate a control system that reverses the direction of rotation of the ground-engaging wheels 16 for a given user input, depending on whether the vehicle is in ground-running or rail-running modes. By way of example, the user input may be via a joystick or lever and it is desirable that a forward press of the lever cause forward motion of the vehicle 10 regardless of the vehicle's running mode.
Desirably a user interface 32 (
The control system could take the form of any suitable arrangement for converting user inputs into appropriate movements of the wheels 16, or command signals to the drive system. The control system could be wholly or partly integrated with the drive system and/or distributed across various portions of the vehicle 12.
When the vehicle 10 is set up to run along rails, and rails of differing gauges, its lateral footprint changes such that the boom orientation at which the vehicle 10 is at risk of toppling changes. Preferred forms of the control system incorporate safety interlocks responsive to the selected footprint of the vehicle 10 to adjust the permissible range of motion of the boom. Following this approach, the range of motion of the boom when the vehicle is on a horizontal roadway is not unduly restricted, and the vehicle is not at risk of toppling when located on a narrow gauge track. Again these safety interlocks may be implemented by any suitable means. By way of example, simple limit switches or more complex software-based approaches may be employed.
This exemplary vehicle may be operated as follows:
With reference to
While the above description refers to various examples, it will be appreciated that other embodiments can be adopted by way of different combinations of features. Such embodiments fall within the spirit and scope of this invention.
While the invention has been described, disclosed, illustrated and shown in various terms of certain embodiments or modifications which it has presumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012904776 | Nov 2012 | AU | national |
