Flow check prevention mechanism

Abstract

This invention relates to a flow check prevention mechanism especially useful in a female coupler for preventing closure of a male coupler coupled thereto should a vacuum occur in the female coupler when fluid flow out of the female coupler is momentarily blocked. The female coupler includes a housing having a bore formed therein with a receptacle movably positioned within the bore. The receptacle contains a main cavity which is connected by a passageway to an engagement bore. The engagement bore receives the male coupler. Located within the receptacle is a main poppet valve which controls the fluid flow through the passageway and a secondary poppet valve which relieves fluid pressure from the main cavity through an outlet port. The female coupler also includes a movable piston which assists in moving the main valve against excessive pressure which may be contained within the male coupler and a collar member which limits the travel of the main valve. The female coupler further includes a flow check prevention valve positioned within the main cavity which assures that the pressure impinging on the piston will be equal to or greater than the pressure present in the remainder of the main cavity. The flow check prevention valve functions to insure that the passageway between the male and female couplers remain open when fluid flow out of the female coupler is blocked by a directional control valve and when a vacuum occurs within the main cavity due to displacement of fluid within the hydraulic function. The female coupler also includes a lever mechanism to assist in the coupling and uncoupling process.