| 摘要 |
<p>1,186,157. Rope fire escapes. J. S. VIRKKI. 24 Feb., 1969 [27 Feb., 1968; 16 Dec., 1968], No. 9761/69. Heading A5A. [Also in Divisions B8 and F2] A rotatable rope drum I adapted to be secured to a worker's safety belt, includes a fluid pressure braking means which resists the drawing off of rope 13 from the drum during a fall of the worker, end of the rope being secured to a permanent fixture. The drum I is rotatably mounted within a casing and around a fixed shaft 4, the latter screw threadedly receiving a piston 5 which is axially movable within a cylinder 1a formed integrally within the drum 1, upon rotation of the drum. A guide 17 mounted in the cylinder 1a slidably engages the piston to rotate the same with the cylinder. Fluid, preferably hydraulic fluid, within the cylinder 1a passes from the left to right side of the piston 5 through an orifice 12 in the piston as the rope 13 is payed out, however during the initial rotation of the drum fluid also passes between opposite sides of the piston through passages 21, 22 in the shaft 4. This permits relatively free movement for the worker for a restricted rope pay out length, after which the fluid flow is more restricted and payout is restrained. The drum 1 is also biassed in the wind up direction by a coil spring 19 coupled between the drum and the casing 14, to prevent any rope slack during the worker's relatively free travel. In a further embodiment Figs. 1 and 2 (not shown) the drum is mounted on e.g. the wall of a building for escape purposes, and the drum is partitioned to form two sections one of which winds a rope up as the other pays out another rope. The fixed shaft is of square cross section and slidingly receives the piston which has its outer periphery screw threadedly engaging the threaded interior of the cylinder whereupon the piston moves axially with rotation of the drum. The only bleed for fluid is an orifice in the piston whereupon the brake acts similarly for rotation of the drum in either direction. The embodiment of Fig. 4 (not shown) is similar to that of Figs. I and 2 (not shown) but the piston threadedly engages the shaft which is rotatable with the drum, the cylinder formed within the drum being non-rotatable and incorporating guides which prevent rotation of the piston but allow axial sliding thereof. The fluid flow between opposite sides of the piston is facilitated by the tolerances on the piston. Valves which may be adjustable, may be placed in the fluid circuit to control the flow between opposite sides of the piston.</p> |
