Land vehicles – Wheeled – Articulated vehicle
Reexamination Certificate
1998-12-22
2001-01-09
Johnson, Brian L. (Department: 3613)
Land vehicles
Wheeled
Articulated vehicle
C280S442000, C280S419000, C180S418000
Reexamination Certificate
active
06170848
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to land vehicles and, more particularly, to articulated vehicles and steering of such vehicles.
BACKGROUND OF THE INVENTION
In the case of a rigid-frame vehicle, the techniques used for vehicle steering are straightforward and well-known. No doubt, the most common arrangement is to steer that pair of wheels which, for the usual direction of travel, is forwardmost. The axles of the trailing wheels are fixed with respect to the vehicle body.
Less common but by no means unheard of is an arrangement in which a rigid-frame vehicle has four wheels, two on each of two steerable axles. The wheel pairs are steerable, either in opposite directions or in the same direction. The latter is known as “crab” steering.
Other types of vehicles are articulated; that is, such vehicles have a pair of rigid frames pinned together for relative pivoting movement with respect to one another. Certain types of articulated construction vehicles are configured in this way and use a pair of hydraulic cylinders to apply force to the frames and change the angle of such frames relative to one another.
Another example of an articulated vehicle, commonly known as a “semi,” is an over-the-road haulage trailer coupled to a towing tractor. Trailer-tractor “jackknifing” is relatively common and a good deal of creative effort had been directed to arrangements to limit the angle that such trailer and tractor can assume with respect to one another. Examples are disclosed in U.S. Pat. No. 3,701,547 (Goold) and U.S. Pat. No. 4,366,966 (Ratsko et al.).
U.S. Pat. No. 5,244,226 (Bergh) discloses a system for steering the wheels of a towed, two-wheel trailer in response to variations in the angle of articulation between the trailer and the steerable towing vehicle. The system compares the angle of articulation and the angle of the trailer wheels, both as a percent of some maximum (although not necessarily equal) angle. The angle of the trailer wheels is the dependent variable and is changed as a function of the angle of articulation.
None of the foregoing examples contemplate (or seem to contemplate) mobile equipment having several trailer-like vehicles pivotally pinned together to form what might be described as a “train.” Mobile equipment of this type is common in underground mines for transporting, i.e., hauling or conveying, the mined product.
Such mining mobile equipment may be characterized in three ways. One is that the number of vehicles pivotally-pinned together may be relatively high, e.g., ten, a dozen or more. Another is that such equipment is routinely moved through relatively narrow, curving tunnels. And another characterization is that the equipment tends to undulate or “concertina” as it is moved along a tunnel. That is, each vehicle does not necessarily faithfully follow the tunnel roadway but, rather, may move from side to side, i.e., transversely with respect to the desired line of travel, as the train of vehicles moves. This makes the equipment more difficult to steer and, in fact, imposes undesirable loads on the towing gear.
And there is another factor which makes vehicle undulation undesirable. In an underground mine, it is common to leave in place a number of vertical columns (sometimes known as pillars) or ribs of the material being mined, e.g., coal. Left-in-place pillars and ribs help support the roof and prevent mine collapse.
An undulating material transport system risks striking one of the columns or ribs and, perhaps, weakening it. As a result, room support is impaired, at least to some degree.
A steering system and method useful on material transport equipment and which address problems and shortcomings of the prior art would be an important technological advance.
OBJECTS OF THE INVENTION
It is an object of the invention to provide an improved steering system for conveyor-like material transport equipment.
Another object of the invention is to provide an improved steering system which helps prevent undulation of material transport equipment operating in a mine tunnel.
Another object of the invention is to provide an improved steering system which helps avoid striking roof-supporting pillars and ribs.
Still another object of the invention is to provide an improved method for steering multi-vehicle, in-line material transport equipment. How these and other objects are accomplished will become apparent from the following descriptions and from the drawings.
SUMMARY OF THE INVENTION
The invention involves an articulated train which, in an exemplary embodiment, is a continuous coal haulage system. Trains of this type have a tendency to “snake” or “undulate” as they travel and the invention substantially prevents such undulation.
In an articulated train, the first vehicle is controllably steered by, e.g., a human operator. The improvement comprises a steering system which locks those vehicles following the first vehicle in an aligned (i.e., nominally straight-line) relationship. As to any vehicle, the system permits such vehicle to be sequentially unlocked and turn only when the vehicle immediately preceding such vehicle has turned through a predetermined number of degrees.
The articulated train includes first, second, third and fourth vehicles pivotally pinned to one another in end-to-end relationship. The steering system includes first means for selectively securing the second and third vehicles in aligned relationship and second means for selectively securing the third and fourth vehicles in aligned relationship. A turn control means, the leading hydraulic valve in an exemplary embodiment, unlocks the first means when the first vehicle turns through a predetermined angle.
The steering system has two closely-similar configurations, both of which involve “sets” of actuators and actuator mechanisms. As to a particular set, the actuator and its actuator mechanism coact with one another.
In the first configuration, the actuator is mounted on the vehicle immediately ahead of the vehicle on which the coacting actuator mechanism is mounted. That is, in a direction of travel, the actuator leads its actuator mechanism. In the second configuration, the actuator mechanism is mounted on the vehicle immediately ahead of the vehicle on which the coacting actuator is mounted. In other words, the actuator trails its actuator mechanism.
In the first configuration of the steering system, the first means includes (a) a first actuator fixed with respect to the second vehicle, and (b) a first actuator mechanism fixed with respect to the third vehicle and coacting with the first actuator. The second means includes (a) a second actuator fixed with respect to the third vehicle, and (b) a second actuator mechanism fixed with respect to the fourth vehicle and coacting with the second actuator.
In the second configuration of the steering system, the first means includes (a) a first actuator mechanism fixed with respect to the second vehicle, and (b) a first actuator fixed with respect to the third vehicle and coacting with the first actuator mechanism. The second means includes (a) a second actuator mechanism fixed with respect to the third vehicle, and (b) a second actuator fixed with respect to the fourth vehicle and coacting with the second actuator mechanism.
In either configuration, the actuator mechanisms have locked and unlocked configurations. And in either configuration, the first means secures the second and third vehicles in aligned relationship when the first actuator mechanism is in its locked configuration. And the first means permits the second vehicle to pivot or turn with respect to the third vehicle when the first actuator mechanism is in its unlocked configuration.
Similarly, the second means secures the third and fourth vehicles in aligned relationship when the second actuator mechanism is in its locked configuration. And the second means permits the third vehicle to turn with respect to the fourth vehicle when the second actuator mechanism is in its unlocked configuration.
In an exemplary embodiment described in detail below, the turn control mean
Earl Lowe, Jr. James
Johnson Brian L.
Joy MM Delaware Inc.
Yeagley Daniel
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