Patent GB-1427759-A (GB)
Title: Cone crusher
IPC: F15B11/08
Filed: 1973-04-05
Abstract: 1427759 Gyratory crushers REXNORD INC 5 April 1973 [5 April 1972 (2)] 16320/73 Heading B2A  A gyratory crusher comprises a bowl 20 Fig. 1 and gyratory head 26 and a bowl-clamping system for clamping the bowl in or on a main frame 10 of the crusher. The system includes means to apply a full clamping thrust to the bowl during normal operation and a partial clamping thrust to remit the bowl and thus the gap to be adjusted while maintaining it in firm contact with the frame or a part thereof and thus permitting continuous operation. The bowl is screw-threaded at 18 in a threaded part 14 of the frame and power-rotated by rams 34 in known manner. Full clamping upthrust is applied at the end of each ram stroke. Upthrust is applied by jacks 46. Downthrust is applied in known manner by Belleville spring stacks 32. In operation, partial unclamping is effected as follows. A valve 62, Fig. 2 is shifted to the right and pressure fluid applied to rams 34. Simultaneously clamp cylinders 32, see also Fig. 1, are engaged. A pressure-reducing valve 70 closes at a preselected pressure to partially unclamp the cylinders 32. The bowl is then rotated one stroke by the rams 34. When the stroke is over, pressure in a line 65 to the rams 34 rises, opens a pilot relief valve 74 and the spring 32 reclamp the bowl fully. Movement of valve 62 to the left retracts the rams. Full bowl unclamping can be effected e.g. by a cable round the bowl. Alternatively the valve 62 can be in neutral and a valve 82 can be operated actuating the cylinder 32 pressurizing simultaneously the pilot valve 86 and closing the pilot valve 72 so that the rams are not extended The jacks 46 are controlled by a valve 90 or alternatively by an independent pump and valve system, Fig. 3. A second embodiment uses dual rams for up and down rotation respectively, which are isolated by a system of valves (128, 130, 132, 134) Fig. 4, (not shown). A third embodiment uses pressure-off clamping, the bowl being spring-biassed up Fig. 5. The same jacks 145 compress the springs that clamp the bowl and also raise the bowl. The jacks have a three step excursion (1) unclamping the bowl for adjustment under load, (2) unclamping for rapid removal, (3) raising bowl for clearance. This is effected by a pilotoperated valve (154) and a throttling valve (152) Fig. 6, not shown. A hand pump can be used to separate jacking from the clamping/ unclamping part of the system.  A pressure-on clamping system keeps the clearance in the threads always at the bottom of the bowl threads during crushing. In this system partial unclamping proceeds by supplying pressure fluid to lock-posts 218, Fig. 9, the pressure being maintained by an accummulator 258. To relieve pressure rams 223 are pressurized until an adjustable valve 274 operates so that the lock-posts still lift the bowl and thus eliminate thread clearance. When the rams 223 have extended to rotate the bowl they retract under control of a reversing valve 232. When the lock-posts are fully repressurized a pressure. sensitive switch 260 shuts off the pump motor 224. For fully unclamping the bowl all pressure is relieved and the bowl rotates freely. An independant jacking circuit may also be provided.