Patent GB-822437-A (GB)
Title: Improvements in or relating to the grinding of frusto-conical liners or mantles for use in crushing apparatus
IPC: B24B5/14
Filed: 1958-02-07
Abstract: 822,437. Grinding. NORBERG MANUFACTURING CO. Feb. 7. 1958 [April 2, 1957], No. 4162/58. Class 60. [Also in Group II] A method of grinding a frusto-conical liner or mantle for use in a gyratory crusher or like apparatus comprises rotating a frusto-conical casting 68, Fig. 1, large end uppermost, about a generally upright axis with the inside and outside surfaces 70, 72 to be ground, which are adjacent the large end of the casting, lying generally coaxial with the axis, and applying rotary grinding wheels 44, 46 on intersecting axes simultaneously against the surfaces so as to ensure concentricity of the finished surfaces. Each grinding wheel is mounted on a spindle 94 which is axially reciprocable by means of a rack 96 and power mechanism in a housing 90 secured to a gear 50 angularly adjustable about a pivot 54 by a worm drive 58 ; both housings 88, 90 are arranged offset and to the same side of their respective pivots 52, 54. The pivots are secured to saddles 34. 36 which are adjustable together or independently by a lead screw 38 on a cross slide 20 vertically adjustable by lead screws 28, 32 and gear boxes 24, 30 on uprights 16, 18 disposed at opposite sides of a rotatable work-table 12. The reciprocation of the spindles is controlled by cams 114, 116, Fig. 2, which are adjustably mounted on a rod 102 carried by brackets 98, 100 secured to the spindle and actuate leveroperated micro-switches 108 to reverse the power drive to the spindles ; a similar arrangement of cams 118, 120 on a second rod 104 is provided to actuate switches 110 in the event of the cams 114, 116 overrunning the switches 108. A bridge 22, Fig. 1, across the top of the uprights 16, 18 carries the various power mechanisms, hydraulic circuits, electric drives and control circuits, and a boom 128 from which depend cables 130 to a control panel 132. Cooling liquid is fed to the wheels by pipes 122, 124'and the machine is provided with covers 60 and an arcuate shield 62 to protect the machine and adjacent equipment. In operation, the casting 68, which is of manganese steel, is held by supports in the form of jaws, hooks or clamps bolted either directly on the power-driven work-table or on a separate plate which has radial grooves provided with locating holes positioned in accordance with the standard sizes of castings to be ground, the latter arrangement permitting one casting to be ground, while a second is set-up on a plate adjacent the machine ready to be lifted by a crane onto the work-table. The spindles are individually angularly adjusted about their respective pivots 52 or 54 to the angles of the surface to be ground and the wheels 44, 46 brought into contact with the surfaces 70, 72, the cams then being adjusted on the rods 102, 104 to limit the length of the strokes of the spindles. The machine is started up and each spindle is fed automatically laterally towards the axis of the casting at least once during each cycle of reciprocation to compensate for the wear of the wheels and the material removed by grinding while the grinding wheel is out of contact with the casting. In another embodiment, a third grinding wheel 138, Fig. 4, is carried by a vertical spindle 136 on a head 134 secured by a bolt 140 to the saddle 36<SP>1</SP> carrying one of the grinding wheels. Towards the end of a grinding operation on a mantle, the grinding wheel 138 is lowered to grind the top surface of the mantle, which surface then acts as a control surface for grinding the edge 144 adjacent the narrow end of the casting after it has been removed from the machine.