Reverse force mechanism

A reverse force mechanism structured to be combined with a device that applies a positive force to a point of application, and adjust a resultant operating force by applying a reverse force to the point of application, the reverse force mechanism comprising:

• a driver formed with a cam surface, and structured to receive a positive operating force from the device in an axial direction, and move in the axial direction;
• and
• a follower including a roller structured to be in contact with the cam surface and apply a contact pressure to the cam surface;
• wherein the cam surface is formed such that:
• a gradient angle varies in accordance with a variation in position of the driver, wherein the gradient angle is an angle between the axial direction of the positive operating force and a tangent to the cam surface and the roller at a point of contact between the cam surface and the roller;
• and
• the resultant operating force, which is a sum of the positive operating force and the reverse force, is substantially constant, wherein the reverse force is produced by the contact pressure, and varies in accordance with the gradient angle.