Constant track tension system for snowmobiles

In combination with a suspension system for a track type vehicle having an endless track means under preselected tension in one position of the suspension system, the suspension system pivotally interconnecting a rigid frame of the vehicle and the vehicle body, and having transverse suspension members adjacent opposite ends of the track means, each member being provided with a pivot axis, the provision of:

• an elongated cam member supported by each of said transverse suspension members and having a cam surface in pressure engagement with the bottom surface of the top lay of said track means and extending in the direction of travel thereof,
• each of said cam surfaces being contoured to maintain said track means under said selected tension with minimal variation of said tension during movement of the suspension system.

In a track type vehicle having an endless track means under preselected tension and provided with a bottom ground engaging track lay and an upper track lay, said vehicle having a suspension member between said track lays, the combination of:

• means for minimizing variation in said preselected tension of the endless track means including
• means carried by the suspension member in fixed relation thereto and in continuous varying pressure contact with the bottom surface of the upper track lay to compensate for movement of the suspension member which causes a variation in tension of the track means.

In a method for minimizing variation in preselected tension of an endless track means provided with relatively fixed end support and guide means and with a relatively movable suspension system, the steps of:

• presetting a selected tension in the endless track means including contacting a cam member with said track means with the track and suspension system in one position;
• and nonlinearly compensating for variations in tension forces acting upon said endless track means during changes in position of said relatively movable suspension system and said cam member with respect to said track means, said suspension system and cam member having fixed relation.

A constant track tension means for an endless track on a vehicle having a vehicle body and a rigid frame, the combination of:

• a suspension frame assembly having one end pivotally connected to the frame and its other end provided with a transverse member connected to the vehicle body;
• and cam means including a cam member having a cam surface for contact with said track means,
• said cam member being fixedly connected to said transverse member at a selected angle to said suspension frame assembly.