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A standard model truck or trailer, having a rear load bearing axle with dual pneumatic tires mounted on wheels at both ends of the axle, is provided a further set of like rear wheels with dual pneumatic tires which are connected to the vehicle\s main frame by depending carriers pivoted thereto. Thes

A standard model truck or trailer, having a rear load bearing axle with dual pneumatic tires mounted on wheels at both ends of the axle, is provided a further set of like rear wheels with dual pneumatic tires which are connected to the vehicle\s main frame by depending carriers pivoted thereto. These rear wheels are rearwardly biased by a compression spring and may be selectively moved forwardly or rearwardly in an arc about their pivotable connection by a hydraulic piston and cylinder arrangement. An endless tread-type track is adapted to be mounted around the succeeding pairs of dual tires on either side. Each track has two or more parts dovetailed together at the ends, held by a spring steel rod inserted in openings therethrough, each opening being defined by a polygonal tube which receives the rod so it cannot rotate. The rod is held in the tube by a detent member. A broad slightly curved plate, rectangular in plan, pivoted from supports depending from the frame forward of at least the rearmost wheels, extends rearwardly centrally between the wheels to where a hydraulic cylinder and piston assembly connects it to the frame to lift the wheels simultaneously for installing the tracks. They are installed by decreasing the distance between the wheels through the hydraulic arrangement and, when in place, by releasing pressure in the connected hydraulic piston and cylinder assembly whereby the compression spring tensions the wheels against them.

대표청구항 ▼

In combination with an agricultural vehicle having a pair of rear wheels with pneumatic tires thereon in tandem on each side thereof which are adapted to receive a removable endless track which connects each said pair of wheels whereby it extends around said pair of tires and moves therewith, at lea

In combination with an agricultural vehicle having a pair of rear wheels with pneumatic tires thereon in tandem on each side thereof which are adapted to receive a removable endless track which connects each said pair of wheels whereby it extends around said pair of tires and moves therewith, at least one of said wheels of each said pair mounted on an axle, the axis of which is retained substantially at a fixed distance under said frame when said track is installed, each said track having a readily connectible and disconnectible connection between opposite ends, lifting means centered between said pairs of wheels as seen from the rear and comprising pivot means mounted on each side of the frame of said vehicle forward of at least one of said tires in each said pair of wheels, a pressure plate for bearing the weight of the rear part of the vehicle, the forward and greater part of which is slightly curved as seen from the side, pivotally connected to both said pivot means at its forward end, said pressure plate having a width substantially equal to the width between the outer sides of said vehicle frame and being so constructed and arranged that the rear part of the weight of the vehicle is distributed substantially continuously transversely across a comparatively large surface of said pressure plate and said wheels on each side thereof are lifted substantially an equal distance relative to said pressure plate and the underlying ground when the rear part of the vehicle is supported thereby, selectively powered extensible means pivotally interconnecting said pressure plate near its rear end to said frame, said extensible means adapted to cause said pressure plate to be pressed against the ground between said wheels and simultaneously lift said wheels so that said tires mounted thereon are simultaneously raised a substantially equal distance above the ground and said tracks can be rapidly installed or removed.