Patent GB-434210-A (GB)
Title: Improvements in and connected with brake mechanisms
IPC: B66D5/26
Filed: 1934-02-28
Abstract: 434,210. Winding-apparatus; brakes. OLIVER, E. H., The Glebe, Dalton-le-Dale, DOBSON, R., 1, Railway Street, Murton, and SIMPSON, J. P., Park View, Murton, both in Co. Durham. Feb. 28, 1934, No. 6524. [Class 78 (v)] [See also Group XXXIV] Brake mechanism for winding, hauling, and lifting gears comprises fluid-pressure control means operative for the admission to the brake engine of augmented fluid pressure when the brake engine is brought into operation by emergency or end-of-the-wind automatic control. The brake engine is operated by fluid supplied through a reducing valve from a main pipe ; when any emergency control becomes operative a byepass valve is opened and full pressure is admitted to the brake engine. Means are provided whereby, when desired, the brake blocks may be set closer to the brake drum towards the end of the wind so that the brakes may act sooner and more effectively. Means are also provided for indicating the amount of wear in the braking mechanism and for bringing the emergency gear into operation if the brakes are excessively worn. In the construction shown, the winding drum a, Fig. 1, is braked by blocks b carried by levers bl operated by the brake engine e through a rod f, link p, arm q, and linkage c. The brake engine e is supplied with air from a main l through a reducing valve m and a hand-operated valve v, the braking being initiated by a weight g on the piston rod f and complemented by the fluid pressure above the piston in the cylinder l. e is the usual cataract cylinder. The byepass valve n is normally held closed by a solenoid H. When the solenoid circuit is broken by a switch operated either automatically or by hand the valve n is opened to admit full braking pressure to the cylinder e, and the overwind mechanism j may be set in operation. The circuit of the solenoid H is completed from the mains through four normally-closed switches 45-48, Fig. 7. 45 is a final limit switch operated by an arm 49 on the nut 50 of the depth indicator d. A similar switch may be provided at the top of the indicator. 46 is a speed-limiting switch adapted to be opened by a solenoid 51 energized by a dynamo 52 driven by and in accordance with the speed of the winding drum. When the winding speed becomes excessive the current generated by the dynamo energizes the solenoid 51 sufficiently to open the switch 46. The solenoid acts at lower speeds toward the ends of the wind, this being effected by means of a contact arm 66 on the nut 50 moving over rheostat contacts 68, 68<a> in circuit with the solenoid, the resistance being cut out at the ends of the wind and inserted gradually as the cage moves away from the end positions. 47 is a switch operated by an indicator 3, Figs. 1, 5 and 7, showing the extent to which the brake-operating piston rod 5 has been moved, the indicator being connected to the rod by any suitable linkage. The indicator has two scales N, S, the first for normal braking when the brake blocks bare set as shown in full lines, and the second for " super " braking when the brake blocks are set closer to the drum as shown in dotted lines. The marks IV, IVA on the scales indicate the full braking position with reduced brake pressure, V, VA indicate full braking with the full brake pressure, and VI, VIA indicate a limit beneath which the pointer should not descend under safe conditions of brake adjustment and condition. If the pointer descends below this limit an arm 9 on the pointer closes a switch 11 and closes the circuit of a signal lamp 53 and, if desired, an audible signal device. Further descent of the pointer causes an arm 10 to open the switch 47 and apply emergency braking. Switch 48 is opened, by means shown in Fig. 6, if the winding drum is started in the wrong direction at the end of a wind. An arm 14, driven in accordance with the movement of the winding drum, moves through about 270‹ from position X to position Y during a complete wind of the cage. At either end of its movement a double pawl 15 on the arm is adapted to engage ratchet teeth 17 or 18 on a rotary disc 16 or 16<a>, the two discs being coupled together by a link 20 so as to rotate in opposite directions. The pawl normally engages the long tooth 17 during the last turn of the winding drum. If the drum is not stopped the arm 14 moves on and rotates the disc 16 or 16a thus moving the link 20 and rocking a lever 22. If the lever is rocked sufficiently a roller 24 on the end rocks a weighted lever 26 and opens the switch 48, Fig. 7, which is enclosed in a casing 30. The switch can also be opened by a hand lever 31. If, after the conclusion of a winding operation, the cage is started in the wrong direction, the pawl immediately engages the long tooth and opens the switch 48 to apply emergency braking. If some small winding adjustment is made in the right direction so that the pawl moves away from the tooth 17, and this is followed by a start in the wrong direction, the pawl will engage one of the ratchet teeth 18 and rotate the disc to open the switch and apply the brakes. When the winding drum has rotated more than one revolution in the right direction the pawl 15 engages an arm 19 on the disc and re-sets both discs. In order to enable any winding adjustments to be carried out within the limits of the first or last revolutions of the drum means are provided whereby the pawl 15 may be moved out of reach of the teeth 18 while still being able to engage the long teeth 17. For this purpose the pawl pivot is slidably-mounted in the arm 14 and can be drawn outwards, when the arm is in either of the end positions, by a solenoid 39 or 39<a> energized by a hand-controlled switch 42, Fig. 7. A signal lamp 41 in parallel with the solenoids indicates when the latter are energized. The means for setting the brake blocks closer comprises a device for varying the effective length of the brake link p, Fig. 1. This link is connected to the arm q by an eccentricallymounted pin ; when the pin is rotated from one dead-centre position to the other, the length of the link is varied. The pin is fixed to a disc s rocked by a piston in a cylinder w, air being admitted to either end of this cylinder from the main l through a valve z controlled by a solenoid P. This solenoid is energized from the mains when a normallyopen switch 54 is closed by a relay magnet 55 which is in parallel with a landing speed signal 56. The relay magnet circuit is only completed when (1) a contact 63 on the nut 50 of the depth indicator closes contacts 60 or 60<a> at either end of the wind, and (2) a switch 58 is closed. The closing of the switch 58 may depend on the energizing of a relay 64 which may be that described in Specification 421,827, in which case the relay will only become active when a sequence of, say, three raps has been given to indicate that men are about to ride. The effect is that when men are riding and as the cage nears the end of the wind the solenoid P is energized and the brake blocks are set closer for securing quick and powerful braking.