Land vehicles – Wheeled – Attachment
Reexamination Certificate
2000-01-31
2001-05-22
Hurley, Kevin (Department: 3619)
Land vehicles
Wheeled
Attachment
C280S767000
Reexamination Certificate
active
06234527
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a lifting device and more specifically a device to lift the trailing end of a road vehicle and allow for its lateral displacement when towed by a tractor or the like.
BACKGROUND OF THE INVENTION
It is known that tractor-trailer units often have steering difficulties, especially when the trailer is long and the road narrow, causing the rear wheels of the trailer to either hit the corner of the sidewalks or go over to corner ditch, thereby causing the trailer to dangerously tilt sideways, when not tilting over and falling off.
In order to avoid the above problems, most of the tractor-trailer units need to take much wider turns, whenever possible, and go over opposite side traffic lanes that may cause road accidents. Also, the tractor-trailer units need to go through much longer road paths to avoid any narrow roads to get to their final destination, thus increasing travel time and reducing the efficiency of the cargo delivery network.
To obviate the above problems, many mechanisms provide for a self steering of the rear wheel train. Such mechanisms, as shown in U.S. Pat. No. 3,930,669 to Kollander et al, U.S. Pat. No. 5,197,751 to Rankel, U.S. Pat. No. 5,213,353 to Williams and U.S. Pat. No. 5,246,242 to Penzotti, are expensive and require special rear wheel trains since they are built-in the latter. Also, in case of breakage of the mechanism, the rear wheel train must be fixed before the trailer can move again, thus causing more problems of towing the trailer away for repair.
OBJECTS OF THE INVENTION
It is therefore a general object of the present invention to provide a lifting device for lateral displacement of the trailing end of road vehicles that obviates the above noted disadvantages.
Another object of the present invention is to provide a lifting device for lateral displacement of the trailing end of road vehicles that allows for lifting of the trailing end of the trailer, or the like, and lateral displacement of the same when it is towed by a tractor.
It is a further object of the present invention is to provide a lifting device for lateral displacement of the trailing end of road vehicles that is easily adaptable to most of the trailers without having to change the existing rear wheel train.
It is yet another object of the present invention is to provide a lifting device for lateral displacement of the trailing end of road vehicles that can be easily mounted in dismounted, in case of breakage, to any trailer.
SUMMARY OF THE INVENTION
The present invention is directed to a lifting device for lifting the trailing end of a road vehicle and used to laterally displace said trailing end, said lifting device comprising a main body including a fixed section adapted to be rigidly secured to said trailing end, a first mobile section essentially vertically movable relative to said fixed section between an elevated non-operative position and a lowered operative position for lifting said trailing end, and a second mobile section being essentially rotatably mounted on said first mobile section, a first actuator device to linearly move said first mobile section relative to said fixed section, a second actuator device for rotating said second mobile section relative to said first mobile section, a rolling device secured to said second mobile section to rollingly engage a road surface, a blocking mechanism to temporarily block said second actuator device from rotating when in said operative position, and a power source to activate both said first and second actuator devices.
Preferably, the rolling device is pivotally mounted on said second mobile section.
Preferably, the lifting device further includes a control device to control the application of power from said power source to both said first and second actuator devices.
Preferably, the first actuator device includes a reversible hydraulic linear actuator and a guide to prevent any rotational displacement of said first mobile section relative to said fixed section, said power source being a hydraulic pump connected to an electrical motor and said control device includes a hydraulic network.
Preferably, the second actuator device includes a reversible hydraulic rotary actuator, said blocking mechanism holding said rotary actuator at a plurality of predetermined rotated positions, all angles between two adjacent positions being equal to each other.
Preferably, the hydraulic network includes a regeneration circuit connected to said linear actuator, said regeneration circuit includes a hydraulic valve and check valves used for rapid raising of said first mobile section from said operative position to said non-operative position.
Preferably, the first mobile section includes an attachment device adapted to be removably engaged by a linear actuator backup device, said hydraulic network includes a pressure relief valve connected to said linear actuator whereby said first mobile section can be raised by said actuator backup and activation of said pressure relief valve upon failure of said linear actuator.
Preferably, the rolling device includes a plurality of wheels, said wheels are mounted with their respective axis of rotation parallel to each other, and a track rotatably engaging and covering all of said wheels.
The present invention is also directed to a combination of two lifting devices, wherein each one of said lifting device is adapted to be secured to a respective side of said trailing end, both said power sources being linked together to similarly and simultaneously activate both first actuator devices and both second actuator devices respectively.
REFERENCES:
patent: 1736498 (1929-11-01), Jensen
patent: 2692143 (1954-10-01), Rando
patent: 2784793 (1957-03-01), Rando
patent: 4605086 (1986-08-01), Marom
patent: 5419580 (1995-05-01), Ku
patent: 5752587 (1998-05-01), Darling
patent: 5807057 (1998-09-01), Nijenhuis
Poulin Jean
Poulin Pierre
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