GB954217A - Improvements in or relating to overwind arresters for use in skip and mine cage winding installations - Google Patents

Abstract

954,217. Overwind arrester gear for mine shafts. H. HITCHEN. Dec. 15, 1961 [Sept. 19, 1960], No. 32074/60. Headings B8B and B8L. [Also in Division F2] A mine cage A or the like is arrested in the event of an overwind by cables C which extend across the shaft between anchorages H and pass round pulleys E, mounted on the piston rods F of hydraulic piston- and-cylinder energy-absorbing devices G, and pulleys D mounted in the shaft. The flow of fluid displaced by the pistons of the devices G is controlled by a restriction or orifice whose magnitude varies in accordance with the linear displacement of the piston. As shown in Fig. 2, the orifice is formed by a tapered stem Q which is located within the hollow piston-rod F and which is secured to the endplate O of the cylinder, and a passage S is provided in the wall of the piston-rod F adjacent the piston T for the passage of hydraulic fluids. A passage M, Fig. 1, allows the free return of the hydraulic fluid to the upper part of the cylinder when the arrester returns to its unoperated condition. In a modification, Fig. 3 (not shown), the cylinder has a tapered bore and the piston is of constant diameter equal to the minimum internal diameter of the cylinder. In a further modification (not shown), a tapered channel is provided longitudinally in the inner wall of a normal piston and cylinder. The arrester device may also be employed at the bottom of the shaft.