| 摘要 |
The door closer acts, for example, between a door hinge stile and a hinge jamb and has a body for mounting usually in the stile, from which body a tension member 12 extends to an anchoring point (for example in said jamb). A hydraulic cylinder-piston damper 17, 31 is interposed between said tension member and a biasing spring 15 therefor, fluid flowing restrictedly past said piston when said tension member 12 and cylinder 17 are moved in door-closing and door-opening directions. The cylinder and piston are formed of a plastics material, e.g. polyacetal, and the cylinder is resiliently expansible in response to an increase in pressure therein such that the clearance between the piston and cylinder is increased to permit increased flow of fluid around the piston. The piston may have passages through it, and the inner cylinder surface, and the piston, may have longitudinal grooves. Member 12 may be an arcuate metal spring strip pivoted at both ends. <IMAGE> |
