Improvements in or relating to braking equipment control systems for mine hoists andlike winding gear

摘要

641,115. Winch brakes. RUMBLE, R. V., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Dec. 18, 1947, No. 33450. [Class 78 (v)] A control system for a mine hoist brake comprises primary and secondary hydraulic control means controlling the flow of fluid through the exhaust conduit of a brake engine 1a; the primary control means (e.g. valve 9) being operable in response to movement of a part (e.g. piston-rod 1) of said brake engine to permit a predetermined proportion of braking effect to be applied irrespective of wear in the brake operating parts; and the secondary control means (e.g. valve 10) being so arranged as to restrict the rate of further retardation of the hoist to a maximum desired value. Figs. 1, 2. Braking arms 5, 6 are pivoted to brake-operating lover 4 which is pivoted at P and is actuated by piston-rod 1, the latter being connected to brake engine la controlled by cataract 2 and weight 3. The fluid circuit passes through parallel conduits 7, 8 governed respectively by large primary valve 9 and small secondary valve 11, the valves being operated by solenoids 11, 12. In the circuit of solenoid 11 is included limit switch 13 having another 13a which is struck by cam 14 adjustably mounted on reciprocable arm 15 pivoted to lever 4, so as to close the switch 13 and so close valve 9. Cam 14 is so adjusted that this occurs after the piston and therefore lever 4 has applied a predetermined (e.g. 50 per cent) fraction of the total braking. After this point the flow of fluid through cataract 2 and therefore the fall of piston of the brake engine is controlled by secondary valve 10. The electrical circuit of the solenoid thereof includes a deceleration detector (e.g. of the type of Specification 571,700) which controls the fall of brake engine piston until the retardation falls below a preset value. The brakes are therefore applied quickly at first and then slowly afterwards. In order to allow for wear of brake-linings switch 13 is fixed on vertical channel member which is adjustably supported by friction linings 19 in fixed supports 18, and it is struck by extension 21 of arm 15 at the end of each complete brake engine movement so that it moves slowly downwards to compensate for the brake wear. Fig. 3. The inlet fluid to brake engine 24 is controlled by valve 22 and the outlet fluid is controlled by primary valve 9 governed as before from switch 13 and by secondary valves 10 and 26, valve 10 being adjustable and inessential and valve 26 being fixed and essential. The two valves 9 and 10 may, alternatively, be in series instead of in parallel. If desired, a speed-responsive switch may be included in the circuit of solenoid 11 so as to give rapid braking throughout the whole of the cage descent and thus to permit only a creeping speed to the cage. Specifications 508,895, [Group XXXIV], also is referred to.