GB1103966A - Automatic door closer - Google Patents

Abstract

1,103,966. Fluid check door closers. DORKEN & MANKELL K.G. 8 June, 1965 [10 June, 1964], No. 24210/65. Heading E2M. In a fluid-check door closer of the type-which is inserted in a door and in which a piston 63 is moved in a cylinder to load a spring as the door is opened, the piston rod 48 has a longitudinal bore in its piston end in which runs a nozzle tube 84 mounted on the other, right hand, end of the cylinder. As the door is opened, the piston moves leftwardly and fluid from the left of the piston flows both past the piston and through a bore 52 in the piston rod, along tube 84 and bores 78, 85 and 77 into space 93. To allow for the varying volume of piston rod present in the cylinder, a compensating chamber is provided beyond the right hand end of the cylinder and supplies space 93 with extra fluid through a one way valve 81 and bore 77 as the door is opened. As the door closes, fluid is expelled from space 93 through bores 77, 85 and 78 into the space to the left of the piston, via nozzle tube 84, and also into the compensating chamber. An adjustment throttle screw 86 in bore 85 controls the closing speed. The volume of the compensating chamber adapts to that of the fluid enclosed by means of a flexible wall 72, thus preventing the induction of air into the system. Nozzle tube 84 is a close fit in a nozzle ring 69, but its diameter may be decreased at certain points to allow free flow of fluid between the tube at those points and nozzle ring 69 to remove checking at the corresponding positions of the door. A relief valve 88 between bore 77 and the compensating chamber prevents damage from excess pressure.