| 摘要 |
<p>A door closer device comprises a body defining an internal chamber in which a piston is slidably received, the chamber, in use, containing hydraulic fluid. A valve is arranged in a passage in the body to permit the fluid to flow through the passage in both directions between spaces in the chamber at respective opposite sides of the piston. The valve has a first part axially adjustable along the passage and a valve member attached to said first part but movable axially relative thereto in the passage between extreme positions where it engages respective stop means on the first member, the valve member allowing fluid to flow unrestricted through an orifice at one end of the passage in one direction when in one of its said extreme positions, and at the other extreme position restricting flow through said orifice in the opposite direction. Preferably the valve member is made of a material having a greater co-efficient of expansion than the material of the body containing said passage, so that expansion or contraction of the valve member with temperature changes enables a more constant door closing speed to be obtained by increasing or decreasing the size of the orifice as the viscosity of the hydraulic fluid also changes with temperature changes.</p> |
