| 摘要 |
1450427 Spring door closers with fluid damping G K N-STENMAN AB 12 Dec 1973 [21 Dec 1972] 57685/73 Heading E2M [Also in Division F2] A spring door closer, of the type in which door shaft 4 provided with a pinion 3 drives a piston 6 within a fluid filled cylinder 5 against a closer spring 9 and a fluid channel 11 links both sides of the piston, is provided with means located in the channel which constricts fluid flow during an initial section of the door closing movement but which widens this constriction during the final portion of the door opening movement. As shown an adjustable valve spindle 13 has a conical end portion 13a which engages in a seat 14a in a slidable sleeve 14 biassed toward the spindle by a spring 16. When the door is opened the piston moves to the left from the door closed position shown in Fig. 1 expelling fluid firstly via channels 11c, lid then, as the piston covers lid, through 11c alone. In this final stage the fluid forces sleeve 14 to the right to widen the constriction between 13a and 14a (Fig. 4). For the first portion of the closing movement i.e. before the piston uncovers channel 11d fluid is drawn into the cylinder through channel 11c forcing the sleeve 14 to the left to narrow this constriction. The slow movement of fluid through this narrowed constriction delays the closing of the door until channel lid is uncovered and provides an alternative passage for the fluid. Final damping of the door occurs as the piston covers exit passage 11a and fluid must flow through a passage 11b regulated by screw 12. A plate 24 resting against a washer 23 provides a safety valve to relieve pressure should the door be closed too quickly, though this may be replaced by a ball valve (Figs. 5-8 not shown). Fig. 9 shows a modification of the constriction means in which the spring 16 acts on a check valve 25 which seats into the sleeve 14 and has a slot 27 for the restricted passage of fluid in its closed position. This check valve provides overload protection during the opening of the door, enabling a larger fluid flow to pass. |
