Patent GB-1101699-A (GB)
Title: Improvements in or relating to gyratory crushers
IPC: B02C2/04
Filed: 1966-07-01
Abstract: 1,101,699. Gyratory crushers. S. A. RICHIER. 1, July 1966 [8 July, 1965; 21 Jan., 1966], No. 29753/66. Heading B2A. [Also in Division G3] In a gyratory crusher of the type in which the movable members rest on a central hydraulic jack, the eccentric carrying and actuating the shaft of the crushing member is journalled in a body which is freely mounted inside the frame of the crusher and rests on the hydraulic jack, the body being subjected to a torque tending to make it revolve in the opposite direction to the crushing member but being connected to the frame by an arrangement including a retaining device associated with the hydraulic jack so that if the torque required for the crushing operation exceeds a predetermined value, the reverse torque acting on the body drives it in the opposite direction to the crushing member and thus acts automatically, through its retaining device, on the hydraulic jack to reduce the crushing action of the crusher until, when the torque is normal again, the initial crushing action of the crusher is restored. In one embodiment, the retaining device comprises a cylinder (22) Fig. 2 (not shown) linked to the frame (2) of the crusher and closed by a cover (23) Fig. 3 (not shown) through which passes a rod (24) linked to the body (10) supporting the movable members (4, 6) Fig. 1 (not shown) and ending in a plunger (25) Fig. 3 (not shown) on which bears one end of a helical spring (28) the other end of which bears against the cover (23), the chamber (29) between the plunger (25) and the bottom of the cylinder (22) being connected by a line (30) with the cylinder (15) Fig. 1 (not shown) of the hydraulic jack (14, 15). When an overload occurs, the spring (28) is compressed and the plunger (25) rises to increase the volume of the chamber (29) so that oil is admitted thereto from the cylinder (15) to cause lowering of the crushing member (4). If abnormal overload occurs, the plunger (25) rises to expose an annular groove (35) Fig. 5 (not shown) which is connected with an oil tank (37) so that oil is quickly expelled with consequent rapid lowering of the crushing member (4). At the same time, the motor (17) driving the crushing member is stopped. In another embodiment, the spacing between the crushing member 43 and the bowl 42 is obtained by means of a hydraulic valve 67 immersed in an oil vat 64 and fed at the same time as the hydraulic jack 55, 56 setting the position of the member 43, the spring- influenced slide (74) Fig. 9 (not shown) of the valve, the position of which depends on the value of the reaction torque, indicated by the arrow 92, acting through a roller (83) Fig. 10 (not shown) keyed on a screwthreaded extension (79) of the slide (74) and acted on by a cam (89) Fig. 9 (not shown) on an arm 88 integral with the crusher body 50, the slide (74) being provided with slits (76) Fig. 9 (not shown) which permit a leakage flow along a line 72 to a basin 73, depending on the value of the reaction torque, while a helical spring 62 bearing on the body 50 counterbalances, under normal operating conditions, the reaction torque. The fineness of grinding is controlled by a hand wheel (86) Fig. 11 (not shown) keyed to a shaft (85) passing slantwise through the valve 67 and provided with a helical gear (84) meshing with a spur gear (87) Fig. 9 (not shown) on the slide (74). The body (68) of the valve is provided with feed and escape grooves (69, 70). If the crushing torque, indicated by the arrow 90, increases beyond its normal value, the reaction torque makes the body 50 pivot slightly to compress the spring 62 and cause the inclined portion of the cam (89) Fig. 9 (not shown) to take up a position below the roller (83). Thus the slide (74) is moved slightly upwards which increases the leakage flow of the slits (76) thereby causing the body 50 and member 43 to be lowered. When a substantial overload occurs, the slide (74) rises substantially so that the grooves (69, 70) are connected and the bore (65) cleared thereby causing quick discharge from the cylinder 56 of the hydraulic jack. A ball valve (93) Fig. 10 (not shown) causes the lowering of the member 43 when the latter is subjected to undue vertical stresses.