US Patent 7357465 Brake pedal feel simulator

A brake pedal feel simulator is provided which reduces the simulation force provided to the brake pedal during emergency or failed conditions. The simulator generally comprises a first spring having a first spring rate and a second spring having a second spring rate. The second spring rate is selected to be lower than the first spring rate. When a predetermined force level is achieved at the brake pedal and simulator, the spring rate provided by the simulator shifts to the second spring rate. In this manner, the rate resistance to translation of the brake pedal is reduced, thereby improving the operator's ability to brake the vehicle.