Fluid door closer with means to permit entrapped gases to move

Abstract

A door closer (20) is attachable to a door (24) and is formed with a chamber (44) in which a piston element (50) is movable to move fluid from the chamber to a reservoir (82) upon opening of the door. After the door (24) has been opened to a position, for example, of sixty to seventy-five degrees, continued opening of the door causes the fluid to be compressed within the chamber (44) and to be directed only through a back check valve (95) to the reservoir (82). This results in the development of an adjustable 'back check' condition to provide a counterforce to the continued opening of the door. The adjustable valve (95) includes a spring biased ball (144), the biasing of which must be overcome by the force of the fluid being compressed in the chamber (44) to allow for fluid to pass through the valve to the reservoir (82). The chamber (44) is formed partially by a spring tube (38) having slots (192) formed in the interior wall thereof which extend radially beyond convolutions of spring (52) contained within the tube. The slots (192) allow the fluid, and gas bubbles entrapped therein, to be moved beyond the convolutions of the spring (52) and to be moved unimpeded into the reservoir (82). Otherwise, the gas bubbles would be trapped in the chamber (44) and would deleteriously affect the operation of the door closer (20).