Abstract: A V belt pulley clutch assembly for a variable speed transmission which may be either the driving or the driven pulley, and which has one movable sheave which is both speed and torque responsive, and wherein the torque responsive portions comprise raised spiral ramps on the hub of the movable portion of the V belt pulley driven through saddle type members riding on the spiral ribs. The ribs are spiraled axially along the hub of the movable portion of the V belt pulley in a direction so that when the driven member is subjected to more load the unit tends to shift into a lower drive ratio. That is when the drive clutch assembly is powered from a drive shaft, the spirals are arranged so that the pulley halves tend to separate under increasing load on the belt. The ribs are on the external surface of a hub and can be die cast draft free for permitting driving and sliding between two relatively movable pulley halves.

Abstract: A safety switch system for use on snowmobiles that eliminates the hazards of previous systems by providing series connected normally closed switches, one connected directly into the throttle control lever which the operator must press for increasing engine speed from idle, and the other mounted directly on the carburetor and controlled by the throttle control arm which is directly connected to the butterfly valve of the carburetor. The two switches are connected to an engine kill system, such as a ground circuit for the ignition. One of the switches must be open for the engine to be running. This means that when the throttle is open (the carburetor control arm is away from idle position) and the operator's hand is off the throttle control lever the engine is dead. However, with the throttle arm in idle position the engine will run whether the operator has his hand on the manual throttle control lever or not.

Abstract: A clutch assembly for use with a V-belt drive which includes centrifugal weight means that tends to change the V-belt drive sheave setting to maintain a selected speed, and further includes a torsion spring and cam device operated to make the setting of the drive sheave partially responsive to the torque carried by the clutch.

Abstract: A unitary, molded combined tool box and air intake duct for use in snowmobiles to save space, minimize expense, and provide for reducing the noise associated with the engine air intake as well as the storage of necessary tools.

Abstract: A frame construction for snowmobiles which utilizes perimeter frame members for carrying the front cross axle for the front ski spindles. The perimeter frame members are attached to and reinforced with respect to the tunnel that houses the drive track to provide a rigid structure that permits a wide spacing at the front of the tunnel for placing an engine and torque converter in a low position, to aid in lowering the center of gravity of the snowmobile, without complex mounting and frame members.

Abstract: A snowmobile which is constructed in a unique manner to provide a tendency to oversteer to the left, which is the common direction for turns in oval track racing. The snowmobile is constructed so that the center line of the drive track is offset from the center line between the two steering ski spindles to create a moment about the center of drag of the steering skis and about the center of gravity which tends to turn the machine in a selected direction.