Adjustable hydraulic backcheck door closer

Abstract

A hydraulic backcheck valve system for controlling an opening cycle of a door closer has a housing with an interior chamber, at least one cylinder, and a piston that can reciprocate between a door closing stroke and a door opening stroke within the cylinder. One side of the piston faces a variable volume chamber in the cylinder and an opposite side of the piston faces the interior chamber of the housing. The backcheck valve system has a fluid passage with a port in fluid communication with the cylinder and an opening in fluid communication with the interior chamber of the housing. The port is blocked by the piston during at least part of the door opening stroke. A one-way valve is disposed in fluid communication with the fluid passage and permits fluid to flow freely during a closing cycle of the door closer and prevents fluid flow from the second passage during the opening cycle. A backcheck valve is disposed in fluid communication with the passage and with the variable volume chamber. The backcheck valve permits metered fluid flow from the second passage to the variable volume chamber during the opening cycle to control the opening cycle.