Patent GB-285211-A (GB)
Title: Improvements in control gear for winding engines, hoists and the like
IPC: B66B1/12
Filed: 1926-12-31
Abstract: 285,211. English Electric Co., Ltd., and Dixon, J. D. Dec. 31, 1926. Regulating and control-transmitting gear for winding-apparatus; brakes; overwinding and overrunning, preventing.-Electrically-actuated control gear for winding-engines comprises normal and emergency braking levers 1, 2 respectively, the lever 2 being shown in two positions at right angles for clearness. The application of the brake depends in all cases upon the de-energizing of the solenoid 5 which allows the valve-carrying core 7 to drop and thus open the cylinder 10 to exhaust, the actuation of the weighted brake arm 42 following in the usual way. A delay action which prevents the brake being taken off until the motor is energized sufficiently to support the load is provided by the resistance 41 and shunt solenoid 6. To energize the solenoid 5 sufficiently, the current must. pass through the shunt, the switch 16 of which cannot be closed until sufficient current is delivered to the motor circuit to operate the solenoid 6. The solenoid circuit is opened when the emergency brake lever 2 is moved from the central to the " trip " position, thus opening switch 13, or when any of the switches 48 are opened automatically by the failure of any of the conditions of normal working such as overwinding, overspeed, the taking of excessive current, or the failure of the braking fluid, supply current in the mains or in the excitation circuits. The triple switch 37 - - 39 included in the circuit opens automatically whenever emergency braking is resorted to, owing to the deenergizing of solenoid 36, and can only be reclosed as a preliminary operation in removing the brake, by moving the lever 2 to the " re-set " position, thus closing switch 14 to reenergize the solenoid 36 through an independent circuit. A mechanical interlock 27, 35 is provided between the two brake levers so that (1) the emergency brake lever cannot be moved to the " re-set " position unless the normal brake lever 1 is in the position in which the clutch is out and the brakes applied; the actual removal of the brakes thus being always effected by the lever 1, and (2) the brake cannot be removed by the lever 1 until the lever 2 has been removed again from the " re-set "to mid-position to reopen the switch 14. Emergency braking is graduated and also cuts off power from the winding-engine, as the movement of the lever 42 opens the switch 9 and de-energizes the solenoid 8, thus allowing the lever 50 to control a cataract cylinder 11 and also operate cut-off gear 15, but during normal braking the switch 38 energizes the solenoid 8 independently of the switch 9 and the power is not cut off. Quick emergency braking near the ends of the run is provided for by the members 44 - - 46 controlled by the depth indicator 17, which prevent the dropping of the rod 47 and the resultant control by the cataract cylinder. The ordinary braking lever 1 works in a " gate " and has a movement at right angles to the plane of the paper to operate the motor controller and a movement in the plane of the paper to open switch 3 and apply the brake. The electric circuit in this case runs from the positive main through switches 48, 13, 39, 3, and solenoid 5 to the negative main. Fig. 3 shows a plan of a special gate for giving a delay action in cases where the normal braking controls a different valve from the emergency braking. The lever 1 cannot move the full length of the angled slots 18, 19 or 18, 20 to take off the brake before it also moves at right angles in the forward or reverse direction sufficiently to energize the motor to support the load. In some instances normal braking may be effected through a circuit which is independent of the emergency braking system. A modified arrangement is illustrated for cases in which the winding-drums are driven by three-phase motors. Specification 284,371 is referred to in the Provisional Specification.