Patent GB-1007637-A (GB)
Title: Grinding machine
IPC: B24B7/07
Filed: 1964-04-29
Abstract: 1,007,637. Grinding. MID-WEST ABRASIVE CO. April 29, 1964 [June 27, 1963], No. 17874/64. Heading B3D. A machine for removing metal from a workpiece W, Fig. 1, such as a slab or billet, comprises a support structure 22, a boom 24 extending from the structure and carrying a grinding unit having a grinding wheel W at its outer end, means 46 pivotally mounting the boom on the structure, and a power mechanism 110 which has a driving pulley 136 connected by a belt 140 to a pulley 138 on the grinding unit, the power mechanism being pivoted to the support structure in a manner such that the weight of the power mechanism tensions the belt. The structure 22 is slidably mounted on L-shaped rails 32 which are mounted on a carriage 10 and have upper and lower surfaces engaged by rollers on the slide to prevent tilting of the structure. An hydraulic motor is drivably connected to a chain 88 which is mounted on sprockets 84, 86 on the carriage and connected to a part on the slide to move the structure towards and away from the workpiece. The carriage is provided with wheels 12, 14 engaging rails 16 and is movable along the rails by a transmission driven by a hydraulic motor. The support structure 22 has upstanding brackets 41, 42, 43, Fig. 9, having axially aligned journals for a pivot shaft 46 which between brackets 42, 43 supports the boom 24 and between brackets 41, 42 supports the power mechanism 110. The boom consists of channel members 50 which carry at their outer ends bearings 55, Fig. 11, for a spindle 54 having its axis extending along the beam. The spindle carries a housing 60 supporting the grinding wheel 20 and its pulley 138 and is angularly adjustable to position the plane of the grinding wheel perpendicular or inclined to the surface of the workpiece or is continuously oscillatable to rock the grinding wheel so that in use its profile assumes a convex shape by a motor 152 connected by a transmission 160 having an output shaft 162 carrying an eccentric pin 164 and slide block 166 engaging a slot 168 in an arm 170 extending from the spindle 54. The boom has a pair of brackets 52 mounted on the shaft 46 between the brackets 42, 43 and is joined by an adjustable resilient connection 141, Fig. 12, to a plate 114 carrying the motor 112 of the power mechanism 110. The motor has a pulley 124, Fig. 1, connected by a bolt 128 to the pulley 126 of a transmission 118 which drives the pulley 136 and has a plate 120 connected by a bolt 130 to the plate 114 of the motor to adjust the tension of the belt 128, both plates being provided with brackets 116, 122, Fig. 9, supported by the pivot shaft 46. The weight of the motor 112 tensions the belt 140 driving the grinding wheel, the amount of tensioning being controlled by adjusting the spring 148 of the adjustable resilient connection 141 between the boom 24 and power mechanism 110. The boom can be rocked about the pivot shaft 46 to raise and lower the grinding wheel by a hydraulic motor 92, Fig. 1, having its cylinder connected to the support structure 22 and the rod 98 of its piston connected to an arm 102 extending from the boom. The carriage 10 includes a platform for a seat for the operator of the machine adjacent a panel housing the controls for the motor 70, Fig. 14, for the carriage, the motor 80 for the support structure 22 and the motor 92 for raising and lowering the boom. The motors are connected in a hydraulic circuit having a motor 174 driving four pumps 176, 178, 180, 182. Pumps 176, 178 are connected by respective lines 184, 186, normallyopen valves 192, 194 and lines 222, 224 to the carriage motor 70. Lines 222, 224 are also connected to valves 230, 232 which are normally in an open position connecting the lines to exhaust. The lines 184, 186 are joined by lines 250, 252 and a solenoid-operated valve 254 to the saddle motor 80. The pumps 180, 182 are connected by lines 106 to the boom motor 92 and by lines 260, 262 to valve 264, 266 which are normally open and connect the lines to exhaust. The pair of valves 192, 194 are controlled by a cam 208 which is rotatable in one direction or the other by a handle 206 to close one or other of the valves. The valves 230, 232 are similarly operated by a cam 208 and foot-pedals 236, 238, and the valves 264, 266 are also similarly operated by a cam and handle 278, the operation of the cam for the latter valves being more gradual than that for the others to permit accurate control of the pressure of the grinding wheel on the workpiece. Operation of one or other of the foot pedals 236, 238 closes its associated valve 230 or 232 to cause a pressure differential across the motor 70 which is thereby operated to move the carriage. The saddle motor 80 is normally locked in position by the valve 254 but when the handle 206 is moved from its control position, the solenoid 256 is actuated to open the valve 254 and the movement of the handle closes one or other of its valves to cause a pressure differential in lines 250, 252 to operate the motor 80 and move the saddle. The motor 80 is normally only operated momentarily at the ends of the stroke of the carriage to cause the grinding wheel to be indexed across the surface of the-workpiece. In the neutral position of the handle 278, the valves 264, 266 are in a position such that the pressure in lines 106 to the boom motor 92 balances the weight of the boom. Movement to one side or the other from the neutral position operates the valves so as to raise or lower the boom and grinding wheel. The motor 112 driving the grinding wheel may be provided with means to vary its rotational speed so that the surface speed remains constant as the wheel wears. Specification 1,007,638 is referred to.