GB1208355A - Centerless grinding system - Google Patents

Abstract

1,208,355. Grinding. SUNDSTRAND CORP. 16 Sept., 1968 [26 Sept., 1967], No. 44005/68. Heading B3D. A bar feed mechanism for a centreless grinding machine comprises a row of a plurality of assemblies, each of the assemblies having a pair of power-driven rolls 107, Fig. 7, for supporting and feeding work bars 50 on a preselected axis 165 to the grinding machine, each roll of each pair being movable on a linear path 109 intersecting the axis 165, the included angle between the paths in each assembly being less than 180 degrees, and power means operatively connected to all the rolls for effecting movement of the same simultaneously on said parts to accommodate work bars of different diameter. Each roll 107 is mounted on a short shaft 105, Fig. 9, carried by a yoke 103 pivotally mounted in a bracket 100 upstanding from a member 97 movable along a slideway 95. The shafts 105 of axially adjacent rolls of the pairs are interconnected by universally-jointed shafts so that all the rolls can be rotated by a common drive motor. A link rod 108 is pivotally connected to the yokes and driven from a servomotor to effect tilting adjustment of the rolls so that they are inclined to the axis 165 to effect feeding of the bar stock. The members 97 of the assemblies are movable along the slides 95 to accommodate various diameters of bar stock by screw-and-nut mechanisms 112, 113 connected by universal joints 132 and worm gearing 130, Fig. 7, to a common shaft 127 driven by a servomotor. One row of a plurality of assemblies effects the infeed of the bar stock and a second row on the other side of the machine effects the out-feed. The bar stock is fed to the row of infeed assemblies from a rack 185 having bar restraining levers 184, bar stop levers 193 and loading arms 207 movable about respective pivots 186, 194, 208 by fluid-operated cylinders 189, 200 and 212, respectively. Cylinders 189, 200 are pivotally connected to a slide 201 movable by a screw jack driven by a servomotor 192 to accommodate different sizes of bar stock. In an alternative embodiment, the rolls 107 are arranged so that one roll of each pair of assemblies is movable along a horizontal path and the other along a path inclined thereto, the movements being effected by screw-and-nut mechanisms interconnected by a chain drive. The centreless grinding machine has a workrest 21, Fig. 11, adjustable along a path inclined towards a regulating wheel 23 of the machine by a worm gear nut driven by a shaft 25. The regulating wheel is driven from a motor and mounted on a slide 29 adjustable along ways 38 on a base 39 by a screw 40 and worm gear nut 41 and a worm 46 on a shaft 47 driven from a servomotor which is also connected by a chain drive 93 to the shaft 25 for adjusting the work-rest. A motor 49 is provided for tilting the regulating wheel relative to the bar stock axis to impart feed to the bar stock. The grinding wheel of a pulley 51 carried by a slidably adjustable yoke 53 on a structure 54, mounted on a base 55. An abrasive belt is trained around the pulley and a second pulley 61 carried by a yoke 62 urged rearwardly to tension the belt by a fluid cylinder 64. In the event of breakage of the belt, the yoke assembly is urged by the cylinder 64 to abut a switch 65 to stop the grinding wheel motor 59 which drives the pulley 51 through a belt 57. The base 55 is urged towards the regulating wheel by a piston-and-cylinder device 67 to a position determined by an abutment 66, Fig. 12, adjustable by a screw-and-nut mechanism 70 driven by worm gearing 73, 79 from a shaft 78 connected to a servomotor.