GB1502605A - Brakes for winding machinery - Google Patents

Abstract

1502605 Winch brakes M B WILD & CO Ltd 25 April 1975 [26 April 1974] 18383/74 Heading B8B [Also in Division F2] A brake operating apparatus for dual parallel calliper brakes 11 of a winding drum 10 comprises dual parallel linkages 13, 14, 15, 17, 19, 20 between a main hydraulic brake engine 16 and the two brakes 11, and an emergency system for alternative brake operation, the dual linkages each incorporating a load cell (60) (Fig. 7, not shown) connected into a circuit which is arranged upon reception of significantly unequal signals from the load cells, to actuate the emergency system. The brake is normally operated by a manual lever 24 which through links 33, 32, 31 operates a main hydraulic brake control valve 35 to exhaust fluid from the brake engine 16. However, the valve 35 is restored to its original position by a compensating move- ment of the link 31 provided through links 26, 27, 28, 29 and 30 whereby incremental brake operation is controlled directly in accordance with brake lever position. The links 20 and 26 are connected to a rod 25 coupled to the main brake engine 16 through a spring box 22 and acted upon by weights 23. Fluid supplied along line 36 from an air, oil accumulator 40 associated with a dual fluid pump, passes through the control valve 35 and through a further valve 46 to the main brake engine 16, the fluid being exhausted from the engine 16 through line 37 when the valve 35 is set appropriately. The valve 46 is solenoid operated to dump fluid from brake engine 16 along a by-pass duct 47 and is actuated by a pressure sensor which maintains the pressure in supply duct 36. An emergency brake engine 21 which may be single or double is controlled through the respective one of two solenoid operated valves 43 controlling fluid supply from the accumulator 40 through a restrictor valve 44 responsive to the position of a lift cage being operated by the drum 10, and fluid exhaust to a reservoir 39. The emergency valve 43 is connected into an electrical circuit which monitors the cage speed and overtravel of the cage so that the emergency system can be actuated automatically on such occasions. The loads in the dual rods 15 are monitored by respective load cells connected into an electrical circuit having a meter and relays. The arrangement is such that if only one of the relays is actuated an audible warning is sounded but if both relays are actuated the warning is sounded and the emergency brake valve 43 is opened to brake the drum 10. The two links 17 incorporate interpenetrating forks with limited adjustable clearance therebetween to permit a predetermined amount of unequal movement whereafter both links move together. In another embodiment the electrical load cells are replaced by fluid systems providing pressure change signals.