Rear spring actuated brake proportioner

Abstract From the Canadian patent

An improved braking system particularly for a vehicle such as a truck subject to relatively large differences in loading including a force responsive proportioning valve inserted between a master brake cylinder and the rear brakes for increasing the rear braking effort relative to the front as the load on the vehicle increases. A spring position follower device is operably connected to the force input of the proportioning valve to respond to angular movements of the pivotally mounted end portion of the rear leaf spring whereby an increased input force is transmitted to the proportioning valve as the spring flexes due to vehicle load increases.