Abstract:
A combination of a snowmobile with its carrying dolly in which the dolly is provided with a leg-like mechanism engageable with the propulsion track of the snowmobile as the snowmobile is loaded onto or unloaded from the dolly. This engagement causes the leg to contact the surface on which the dolly stands, thus acting as a brake to hold the dolly in position during the processes of loading and unloading.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION 
     This invention pertains to carrying devices, particularly carrying dollies for the machines known commonly as snowmobiles. Such dollies are common. They consist of a T-shaped bed on which the snowmobile rests. The two front skis of the snowmobile rest on pads on the cross member of the T-shape, and the powered track or belt rests on the upright of the T-shape. Casters are used to allow the dolly and its load to be readily moved for storage or the like. 
     Problems arise in driving the machine off the dolly. Snowmobiles commonly have no reverse gears so they are driven forwardly off the dolly. As the skis move from the pads and drop to the supporting surfaces, there is a tendency for the driving belt on the machine to drive the supporting dolly back and for the casters to simply allow the dolly to roll rapidly on the floor to the rear of the snowmobile. This action can endanger people or property standing to the rear of the dolly. 
     The present invention provides a mechanism by which the dolly can be frictionally inhibited from rolling on the supporting surface so that the snowmobile can be unloaded without that danger. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view of a snowmobile-carrying dolly having the anti-kickback device in place, 
     FIG. 2 is a side elevational view of the device of FIG. 1, 
     FIG. 3 is an end elevational view of the device of FIG. 1, 
     FIG. 4 is a detailed side elevational view to an enlarged scale of the anti-kickback device in a contact position, 
     FIG. 5 is a view similar to FIG. 4 with the anti-kickback device in its free position as the snowmobile is loaded, and 
     FIG. 6 is a view similar to FIGS. 4 and 5 showing the anti-kickback device in its full downward position. 
    
    
     DESCRIPTION 
     Briefly this invention comprises a snowmobile carrying dolly having a simple and automatic control of the rearward motion of the dolly as the snowmobile drives off the dolly. 
     More specifically and referring to the figures, the device comprises a T-shaped framework composed of a leg 10 and a cross member 11. The cross member 11 is formed as a rectangular frame made up of long side bars 12 which may be square tubing, angle iron or other shaped member and cross bars 13 of similar cross section. At each end of the frame member 11 are located pads 15. Ramps 16 sloping upward to the pads 15 are also preferably provided. End walls 17 may also be provided to mark the outer boundaries of the cross member. 
     This part of the assembly is adapted to receive the front skis of the snowmobile. The shape of the structure is common for the type of dolly envisioned. 
     The leg 10 is releasably joined to the cross member 11. Socket members 18 are fixed to one cross bar 13 of the cross member 11, and the side bars 19 of the leg are inserted and bolted into the sockets by bolts 20. This allows ready disassembly of the dolly for more convenient storage and especially for shipping. 
     Essentially this leg is also an open framework composed of side bars 19 joined together by cross members 21. A plate 22 is preferably used as a cross member at the free end of the leg 10 to provide added strength and stability. 
     Casters 25 are provided at the free ends of both parts of the entire framework. The casters provide for ready mobility of the frame and particularly its burden after the machine is loaded onto the dolly. However, the casters also contribute to the problem solved by the present invention. The plate 22 may also provide a mounting place for the rear casters 25. 
     In loading the dolly, the snowmobile is driven up to the framework with the drive belt first contacting the plate 22. As the machine moves forward, the skis engage the ramps 16 and the entire assembly climbs onto the dolly with the belt extending forward from the plate 22 a considerable distance. It should be noted that all of the driving force of the belt acts on the dolly itself, thus tending to force the dolly under the snowmobile. 
     Within the distance by which the belt extends past the plate 22, the present invention requires a tilting plate 30 pivoted on an axle 31 fixed to the side bars 19. Although the plate 30 may be simply a flat plate, the preferred embodiment would provide a channel shaped structure having a flat plate bordered on its edges by flanges through which the axle 31 extends. As shown in the succession of figures starting at FIG. 5 then to FIG. 4 and finally to FIG. 6, this plate can pivot from a nearly horizontal position (FIG. 5) through about 90° to a near vertical position (FIG. 6). A rod 32 transversely fixed on the leg 10 is positioned to form a stop device so that the plate 30 does not pivot past the position shown in FIG. 6. That position is preferably just slightly over the center so that it will be held by gravity. 
     An operating vane 35 extending along the length of the plate 30 extends upwardly from the plate 30 as shown in the figures. This vane is located where it will be contacted by the driving track of the snowmobile. It is this contact which makes for the automatic operation of the anti-kickback action of the dolly. 
     In operation, as the snowmobile drives onto the dolly, the track contacts the vane 35 to tilt it forward. Such tilting causes the plate 30 to move upwards to the near horizontal position shown in FIG. 5. In this position, the casters 25 are free to roll and the assembly of the dolly and snowmobile can be moved about on the casters freely. 
     Unloading makes for a different problem. Because most snowmobiles have only forward powered motion, the machine is driven forward. When the driven track clears the vane 35, the heavier weight of the plate 30 causes the device to pivot downwardly to the contact position of FIG. 4. A rubberized or composition material may be used to provide a band 36 of material on the bottom of the plate 30. This band tends to prevent slippage between the plate 30 and the surface on which the assembly is then supported. Because of the non-slippage, the dolly is held in place as the snowmobile is driven off and will not be propelled across the floor or other surface to the danger of other people or material standing around. Even if there is more force than is resisted by mere contact as shown in FIG. 4, the plate 30 may be pivoted against he stop 32 to give added protection. In this position, shown in FIG. 6, the casters 25 on the leg 10 will ordinarily be raised from the floor, thus adding the full weight of the leg 10 onto the plate 30 and increasing the friction between the floor and the plate 30 to provide added force holding the dolly in place. 
     In reloading the dolly, as the driven belt again contacts the vane 35, the plate 30 will again be pivoted upward so that the dolly again will rest on the casters and be readily moveable.