Park brake interlock and trailer brake valve assembly

A brake system for a tractor-trailer vehicle comprising:

• a trailer hand control valve selectively actuated to provide braking to a trailer;
• a park brake control valve including at least a first actuator for moving a tractor park brake between applied and released positions and a second actuator for moving a trailer park brake between applied and released positions;
• a tractor protection valve fluidly connected to said park brake control valve;
• and
• an interlock valve assembly including a valve body with a plurality of inlets comprising a first interlock inlet adapted for fluid connection to said trailer hand control valve and a second interlock inlet adapted for fluid connection to an air supply and wherein said valve body includes a plurality of outlets comprising a first interlock outlet fluidly connected to said tractor protection valve and a second interlock outlet fluidly connected to said park brake control valve, and wherein said interlock valve assembly includes a valve assembly cooperating with said first and said second interlock inlets and said first interlock outlet to supply an air signal to said tractor protection valve from one of the air supply and said trailer hand control valve to apply a trailer brake, and wherein said valve assembly cooperates with said first interlock inlet and said second interlock outlet to fluidly connect said park brake control valve to the air supply to release at least one of the trailer park brake and tractor park brake.

A method for controlling trailer braking comprising:

• (a) providing an interlock valve assembly fluidly connecting an air supply to a park brake control valve;
• (b) fluidly connecting the interlock valve assembly to a tractor protection valve;
• and
• (c) communicating an air signal from the interlock valve assembly to the tractor protection valve in response to a trailer brake commend.