Patent GB-424223-A (GB)
Title: Improvements relating to braking equipments for moving apparatus such as hoisting, winding, hauling and like gear
IPC: B66D5/26
Filed: 1933-10-25
Abstract: 424,223. Winding-apparatus. SMITH, D. M., 37, Church Street, Stretford, Manchester, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. Oct. 25, 1933, No. 29611. [Class 78 (v)] [See also Group XXXIV] The brake of a mine winding or other apparatus is automatically controlled to maintain a predetermined speed, which may be automatically varied according to the position of the cage or other part to be controlled, by a pump or metering device adapted to deliver fluid to a cylinder at a rate dependent upon the speed, the cylinder having an aperture the size of which is controlled by a piston whereby the piston assumes a position dependent on the speed and actuates a relay controlling the brakes. The relay may also be automatically operated when the normal limit of travel of the cage &c. is exceeded. The equipment shown comprises a gearwheel pump 1 driven from the winding drum, a change-over valve 52 automatically actuated appropriately to connect the inlet and delivery passages of the pump according to the direction of movement of the drum and cage, and a valve 5 operating a relay 28 which controls the brake. With the valve 52 in the position shown, oil under pressure supplied from pipe 3 through a pressure-reducing valve 51 and pipes 50, 1<1>, is delivered by pipes 1<11>, 41, to cylinder 4 having a longitudinal aperture 6 thence to exhaust pipe 8. The aperture is controlled by a plunger 9 which is subject through pipe 50 to the inlet pressure of the liquid supply and the plunger thus assumes a position in which it sufficiently uncovers the aperture to pass liquid at a rate proportional to the speed of the winding drum under the constant pressure difference across the pipes 50, 8. The plunger 9 co-operates with a ported sleeve 15, the position of which determines the desired speed. A relay piston 29 connected to the valve of the brake engine is subject on its upper face constantly to the supply pressure in pipe 3, the chamber 28 below the piston being connected by the pipe 28<1> and valve 5 either to pressure pipe 3 or to exhaust pipe 8 or being cut-off from both as is shown. Thus, if the plunger 9 rises due to increase of the speed, the chamber 28 is connected to exhaust pipe 8 and the piston 29 moves downwardly to apply the brake. The piston is connected by levers 291, 19 to the sleeve 15 which thus receives a follow-up action. A foot lever may be connected to the valve of the brake engine in such a way that the brake action may at any time be increased but not diminished. A valve may also be arranged in the pipe 28<1> adapted to be opened by de-energization of a solenoid in emergencies to exhaust the chamber 28 and apply the brake. In order that the speed may be determined by the position of the cage the lever 19 connected to the sleeve 15 rides upon either of two cam discs 21, 40 which may be driven by the depth indicator so that a complete revolution of the discs represents the complete travel of the cage. The discs determine acceleration and deceleration periods at the ends of travel with intermediate periods of constant speed. The two discs 21, 40 have different profiles to effect, for instance, different values of acceleration and deceleration according as the cage is being used for men or material and the lever 19 is engaged with the one or the other by a lever 46. The changeover valve 52 is actuated at each change of direction of travel to interchange the inlet and delivery pipes of the pump 1 so that the delivery pipe is connected to the cylinder 4 irrespective of the reversal of rotation of the pump. The valve is controlled by a pilot valve 53 adapted to connect the upper end of the valve either to the pressure pipe 50 or to the exhaust pipe 8 and may as shown be actuated by a link 56 subject to conjoint control of a friction clutch 57 and a cam disc 59 driven by the winding drum so that the change-over valve is not actuated until after the initial acceleration period of the travel and during this period the pump withdraws oil from the chamber 4 so that the plunger 9 falls to its lowest position and is ineffectual for applying the brake. A simple hand-controlled valve may be substituted for the valves 52, 53. A pressurerelief valve 48 is adapted to connect the inlet and outlet pipes of the pump when the pump is tending to draw liquid from the cylinder 4 to prevent the inlet of air to the pump circuit. Automatic operation of the brakes in the event of an overwind is effected by the engagement of either of two cams 65, 66 driven in opposite directions by the winding drum, with valves 61, 62 adapted to connect the relay cylinder 28 to chamber 74 or 75 normally connected to exhaust pipe 8. A second pair of cams 71, 72 and valves 69, 70 may be rendered effective by the hand lever 46 when operation of the brakes at a different limit of travel is desired. The hand lever actuates a valve 67 to connect the relay cylinder 28 to the chamber 68 of the valves 69, 70. The brakes are released after an overwind by closing valves 78, 82 by a pedal 80 and by closing valve 77 or 81 by the reversing lever 79, the arrangement being such as to ensure that the cage &c. can only be restarted in the reverse direction to that during which the overwind occurred.