Remotely adjustable degrees of freedom for suspension coupling

A method for dynamically controlling stiffness in a snowmobile suspension system, the method comprising:

• providing a communication line operative to conduct a coupling mode signal from a proximal end thereof to a distal end thereof;
• providing a rear torque arm pivotally coupled at a distal end of the rear torque arm to a tunnel of a snowmobile;
• providing a scissors member pivotably coupled about a distal pivot point at a distal end of the scissors member to a proximal end of the rear torque arm, wherein the scissors member pivotably couples about a proximal pivot point at a proximal end of the scissors member to an elongate slide rail of the snowmobile;
• providing a rear shock member providing spring bias support to the first pivot point relative to the slide rail;
• providing a Remotely Adjustable Shock Member (RASM) having a first end and a second end slidably coupled to each other so as to permit contraction and expansion of a separation distance between the two ends, wherein the first end of the RASM couples to the elongate slide rail, and the second end of the RASM couples to the scissors member, wherein the RASM is further operatively coupled to receive the coupling mode signal at the distal end of the communication line,
• wherein pivoting of the rear torque arm and the scissors member about, respectively, the distal pivot point and the proximal pivot point, represents two degrees of freedom of the distal end of the rear torque arm relative to the slide rail, and
• removing one of the two degrees of freedom of the distal end of the rear torque arm relative to the slide rail in response to the coupling mode signal indicating a first mode.

A snowmobile rear suspension system with dynamically controllable stiffness, the snowmobile rear suspension system comprising:

• a communication line operative to conduct a coupling mode signal from a proximal end thereof to a distal end thereof;
• a rear torque arm pivotally coupled at a distal end of the rear torque arm to a tunnel of a snowmobile;
• a scissors member pivotably coupled about a distal pivot point at a distal end of the scissors member to a proximal end of the rear torque arm, wherein the scissors member pivotably couples about a proximal pivot point at a proximal end of the scissors member to an elongate slide rail of the snowmobile;
• a rear shock member providing spring bias support to the first pivot point relative to the slide rail;
• and,
• means for remotely adjusting stiffness of the distal end of the rear torque arm relative to the slide rail, the remote stiffness adjusting means being operatively coupled to the distal end of the communication line to receive the coupling mode signal,
• wherein pivoting of the rear torque arm and the scissors member about, respectively, the distal pivot point and the proximal pivot point, represents two degrees of freedom of the distal end of the rear torque arm relative to the slide rail, and
• wherein, in response to the coupling mode signal indicative of a first mode, the means for remotely adjusting stiffness substantially fixes a relative position of one of (i) the rear torque arm relative to the scissors member, or (ii) the scissors member relative to the elongate slide rail, so as to remove one of the two degrees of freedom of the distal end of the rear torque arm relative to the slide rail.