NL6708641A - - Google Patents

Abstract

1,158,963. Automatic door closing apparatus with a shock-absorbing plunger. AUGUST BILSTEIN K.G. 19 June, 1967 [21 June, 1966; 16 Aug., 1966], No. 28110/67. Heading E2M. An automatic door closing apparatus, having adjustable clamping and shock-absorbing power and as illustrated with reference to Figs. 1 to 4, comprises a cylinder 1, a first end wall 2, a second end wall incorporating a stuffing box 11', a gas and fluid-tight displaceable plug 3 mounted in the cylinder, said plug, cylinder and first end wall defining a space 1' for receiving pressurized gas, and said plug, cylinder and second end wall defining a space for receiving hydraulic or pneumatic fluid, a piston rod 11 extending through said stuffing box, a piston 4 having a non- return valve means (5, 6) and being mounted so as to define two chambers 1" and 1"' of variable volume between said plug and second end wall, and passage means (bores 7, 9, 9') by-passing said non-return valve means so as to permit fluid flow between said two chambers, and being so arranged as to vary the rate of flow of fluid in dependence upon the location of the piston in the cylinder. Other features described which allow for varying the fluid flow resistance are the provision of a resilient annular sealing element 14 having a gap 15 which may be moved into different positions relative to the longitudinal grooves 'in the cylinder wall; the provision of bores 34, 35 in the piston rod sealed off by part 41 of stuffing box shortly before fully closed door position; the provision of bore 36 in the wall of the piston; the arrangement of the piston on a bushing displaceable against a spring 39 whereby the entrance to a groove 38 is freed. The apparatus may be mounted on a door and frame as descrilbed with reference to Figs. 5 to 8 (not shown).