Abstract: A preventative stop valve system for a wheeled trailer carrying hydraulic equipment is disclosed comprising a stop valve fitted for insertion in-line into the hydraulic line servicing the trailer equipment; the stop valve comprising a reciprocating piston moveable between open and closed positions. The stop valve is connected to the pressurized air line extending to the air brakes of the trailer. Actuation of the stop valve is controlled pneumatically by the setting and release of the air brakes of the trailer by the operator, utilizing conventional controls for the air brakes. A manual override mechanism is further provided for opening the stop valve manually in the event that the hydraulic equipment carried by the trailer must be utilized when pressurized air line to the trailers is disconnected.

Abstract: A preventative stop valve system for a wheeled trailer carrying hydraulic equipment is disclosed comprising a stop valve fitted for insertion in-line into the hydraulic line servicing the trailer equipment; the stop valve comprising a reciprocating piston moveable between open and closed positions. The stop valve is connected to the pressurized air line extending to the air brakes of the trailer. Actuation of the stop valve is controlled pneumatically by the setting and release of the air brakes of the trailer by the operator, utilizing conventional controls for the air brakes. A manual override mechanism is further provided for opening the stop valve manually in the event that the hydraulic equipment carried by the trailer must be utilized when pressurized air line to the trailers is disconnected.