Patent GB-1389816-A (GB)
Title: Grinding machines
IPC: B24B49/00
Filed: 1973-06-13
Abstract: 1389816 Grinding SUNDSTRAND SYRACUSE Inc 13 June 1973 [14 June 1972] 28058/73 Heading B3D A grinding machine comprises a number of grinding stations 35-1, 35-2, 35-N each having powered adjusting means for moving a grinding head 50 and work support means 54 toward and away from each other in response to requirements, powered feed means 40, 38 for feeding workpieces to and from the grinding stations, powered adjusting means for moving the powered feed means to accommodate workpieces of different sizes, an input gauge effective for determining the size of a workpiece prior to grinding, and set-up means automatically responsive to the input gauge for energizing the powered adjusting means to position the grinding heads, work support means of the grinding stations and the powered feed means for a new workpiece of a different size. The machine is described as of the centreless type having a number of stations 35-1, ... 35-N, and powered guide rolls 38 feed work bars between the stations which are disposed between a left load/unload table 30 and a right load/unload table 32, the tables housing powered rolls 40 for feeding the bars. Each station has a grinding head 50 comprising a contact wheel 62 which is driven by a motor 63 and over which runs an abrasive belt. The head is advance towards a work bar 52 by a ball screw 74 driven by an actuator and has a rack 80 engaging a pinion 82 driving an encoder 84 which senses the position of the head. A dresser 64 contacts the abrasive belt and an encoder 66 monitors the wear of the belt. The work bar 52, irrespective of diameter, is supported on a common pass line by a regulating wheel assembly 54 and a work rest structure 56. The assembly 54 has a wheel 90 provided with a dresser and diameter compensation mechanism 92 and an encoder for monitoring wear of the wheel. The assembly is movable by a ball screw 97 driven by an actuator 96 and a rack 104 engages a pinion 105 driving an encoder which senses the position of the assembly. The structure 56 has a work rest blade 120 extending through a jack 122, the position of the blade being sensed by an encoder 126 driven by a pinion 125 engaging a rack on the jack. The support rolls 40 of the tables 30, 32 and the guide rolls 38 between the grinding stations are similar and consist of rolls 134, 135, Fig. 3, which are movable radially of the work bar 52 by mechanism 140 to maintain the workbar on a common centre line irrespective of diameter, the position of the rolls being sensed by an encoder 144 driven by a pinion 142 engaging a rack. The rolls are canted to feed the work bar through the grinding stations. The tables 30, 32 are similar and the angle of a rail 150, Fig. 4, can be adjusted by a jack 152 driven by an actuator 154 according to whether the table is used for loading or unloading, the position of the rail being sensed by an encoder 156. When the table 30 or 32 is used for loading, the work bars 52 rest on the rail which is in its upper position at an angle determined by the diameter of the bars. A stop arm 160 normally retains the bars on the rail and can be lowered by actuation of a jack 162 to permit the bars to roll until stopped by a release arm 165. The height the arm 160 is raised is adjusted, according to the diameter of the bars, by a screw 175 driven by an actuator 176, an encoder 177 sensing the position of the arm. Stop arm is raised to hold all but the lowermost bar 52 which, when release arm 165 is lowered, rolls on to a load arm 172 for lowering onto the rolls 40. The release arm is actuated by a jack 170 adjusted, according to the diameter of the bars, by a screw 180 driven by an actuator associated with an encoder 183. Each table 30, 32 has a process gauge 200, Fig. 5, for pre-gauging or post-gauging the bars which are being loaded at one table and unloaded at the other. Each gauge is mounted on a storage arm 205 and a bar is located by a release arm 207, which may be similar to arm 165, while a slide 214 is moved into engagement with the bar by a cylinder 212, the slide moving along a vertical support 210 and its position being sensed by an encoder 220 driven by a pinion 216. The bars are measured at each grinding station by a respective gauge 230, Fig. 6, consisting of probes 232 consisting of proximity elements. The probes are mounted on flanges 234 movable by a ball screw 236 driven by an actuator 240, the position of the probes being determined by an encoder 242. The machine is controlled by a master controller/computer, Fig. 7, having an input from the gauge 220 and a final diameter preset. Each grinding station 35-1, 35-2; 35-N has controls 310, 312, 314 for the head, regulating wheel and blade which are controlled by respective offset devices 408, 410, 412 which determine the amount of material to be removed at each station. In a machine having five stations, the first and second may remove 45 % each, the third 10%, and the fourth and fifth effecting a finish grind only. The guide rolls 38 between stations are adjusted by controls 318 and the rolls 40 of the tables 30, 32 are adjusted by controls 320, 322. The stop and release arms 160, 165 and height of rail 150 of the tables 30, 32 are set by controls 326, 328, 330. The feed of the bars 52 through the machine is set by a variable frequency speed control 335 acting of the rolls 40, 38. The controller acts to set each of the controls in accordance with the size of the bar measured by the pre-process gauge 220 and the desired final size of the bar. During positioning of the grinding heads, the heads are always moved in one direction to eliminate backlash.