Patent GB-1044788-A (GB)
Title: Crushing apparatus
Inventor: LEMARDELEY C
IPC: B02C2/04
Filed: 1963-11-19
Abstract: 1,044,788. Hydraulic apparatus. BABBITLESS. Nov. 19, 1963 [Nov. 27, 1962], No. 45623/63. Heading F1P. [Also in Divisions B2 and G1) A device operating in the event of the entry of tramp material into the crushing gap of a gyratory crusher to control and adjust downward motion and resetting in position of the crushing cone 2 whose shaft 1 is suspended by an hydraulic jack 4, comprises pressure-sensitive means 12 responsive to the pressure of fluid under the jack piston to control the opening of a discharge valve 18 for the fluid when the pressure reaches a predetermined value, means 20 to maintain the valve open for a predetermined time independent of the pressure, means comprising a compressor 8, motor 9 and fluid tank 10, to feed hydraulic fluid to the jack, means 24 to start feed at a predetermined time after opening the valve, and means 25 . . . 27 to interrupt feed when the cone has been restored to its operating position. In operation, the cone 2 is normally maintained, by pressure in the jack 4, at its upper position as determined by the length of a rod 27, so that a contact 26 is broken, relays 25, 23 de-energized, a switch 22 open and the motor 9 stopped. Tramp material entering the crushing gap increases the jack pressure causing the pressure-sensitive circuit-breaker 12 to energize the relay 21 and operate a timing contactor 20 to energize a solenoid 19, and open the valve 18 (the contactor 20 remaining closed), thus relieving the pressure via the pipe 17. The pressure is allowed to fall because operation of the contactor 20 maintains solenoid 19 energized until the fluid jack 5 is evacuated. The downward movement of the piston moves the rod 27 correspondingly so that contact 26 closes, energizing the relay 25 and starting a timing contactor 24. After a predetermined time, the contactor 24 closes, energizing the relay 23, closing the contacts 22 and restarting the motor to pump up the jack and restore the shaft, until the rod 27 again opens the switch 26 to a stop the motor. Instead of a rod 27 on the cone co-operating with a fixed switch on the crushing ring, or vice versa, control may be effected by measuring the fluid volume admitted under the jack piston, or if a double-acting jack is used, the volume expelled from the upper chamber above the piston or the pressure established in the upper chamber or in an accumulator connected thereto, a volume meter or pressure gauge controlling the switch in the circuit of relay 25. The rod and contact system is adjusted when crushing size is to be varied e.g. by a hand control. Alternatively, an adjustable resistor arrangement may be used wherein the switch 26 is replaced by a movable contact 26a, Fig. 2 (not shown), controlled by the pointer 28 of a galvanometer 29 supplied with current via a rheostat 31 having a controlling arm 32 secured to the shaft. As the shaft rises current increases through the galvanometer until the needle opens the contact 26a to stop the motor 9. Alternatively, a photo-cell may be connected across the galvanometer and a screen of decreasing transparency secured to the shaft so that a light directed on the screen and cell produces a current in the galvanometer which varies with shaft-position.