Patent GB-847855-A (GB)
Title: Machine for the application of a milling method
IPC: B24B5/04
Filed: 1957-12-30
Abstract: 847,855. Grinding. TOUQUET, E. Dec. 30, 1957 [Dec. 28, 1956], No. 40242/57. Class 60. A grinding machine comprises interlinking means between the means for imparting feed movements to a grinding wheel 1 in a direction perpendicular to the axis of the wheel, the means for imparting feed movements to a dressing tool 41 for clearing the abrasive grains apparent on the surface of the grinding wheel, and the means for imparting feed movements to the means 70 for projecting lubricant fluid onto the contact points between the grinding wheel and a workpiece P, said interlinking means ensuring that the feeding movements of the means for projecting lubricant fluid move in the opposite direction to the other feed movements. The grinding wheel 1, Fig. 1a, is preferably constructed with a felloe 2 secured - to a hub 3 mounted on the tapered end of a shaft 7 which is disposed in a bearing 11 on a slide 18 movable perpendicularly to the axis of the grinding wheel in guides 19, 20 by a screw 22, Fig. 1b, engaging a nut 21 secured to the slide ; the other end of the shaft carries a pulley connected by a belt 15 to an electric motor 17 also mounted on the slide. The screw 22 is prevented from axial movement by a bearing 40 secured to the frame of the machine and carries a gear 24 engaging a worm 36 on a transverse shaft 37 journalled in bearings 38, 39 in a casing 34. The gear can be rotatably secured to the screw 22 by a cone-clutch 25 which is axially movable on splines on the screw against a spring 35 by means of a forked member pivoted at 28 engaging a groove in the clutch and rockable by a hand-lever 29. With the clutch in the disengaged position, the screw can be rotated by a hand wheel fitted to its squared end. The support 52 is similarly movable in guides on the slide 18 by means of a screw 56 engaging a nut on the support, the screw being prevented from axially moving relative to the slide 18 by a bearing 66 carried by the slide. The screw carries a gear 24<SP>1</SP> which engages a worm on the shaft 37 and is releasably secured to the shaft by a similar case-clutch mechanism 25<SP>1</SP>. The dressing tool, is mounted on a carriage 50 reciprocable in a direction parallel to the axis of the grinding wheel by a piston-and-cylinder device 77, 79. The tool has a rearwardly extending stem 43, Fig. 8, which is spring-urged into contact with a cam 82 shaped to the profile to be maintained on the grinding wheel. A portion 58, Fig. 1b, of the screw 56 is provided with a screw thread which is of equal but opposite hand to that on the part engaging the support 52 and engages a cross-beam 61 clamped to pipes 64 connected at one end to a source of lubricant and at the other end to nozzles 70 which are flattened to extend the width of the grinding wheel and to extend as near to the point of contact between the wheel and workpiece as possible. A flexible pipe 74 is connected to one of the pipes 74 and to the carriage 50 to direct lubricant onto the dressing tool and grinding wheel. The workpiece P may be mounted between a chuck and centre 104 movable by a screw 106 driven by a prime mover. In operation, the transverse shaft 37 is rotated to rotate the screws 22, 56 in opposite directions by a pawl, 87 Fig. 7, which engages a ratchet wheel 85 and is carried in one end of a rocking lever 86, the other end of the lever being connected to a piston-and-cylinder device 91, 92, the number of teeth engaged by the pawl, and hence the amount of rotation of the screws 22, 56, during the stroke of the piston 92 can be determined in accordance with the wear of the grinding wheel by a strip 96 which can be moved'to mask a selected number of teeth on the wheel 85 by means of a rack and pinion 97, 98, the pinion being secured to a lever 100 which can be moved to positions determined by a pin engaging holes in an arcuate strip 103. Rotation of the screw 22 moves the slide 18 carrying the grinding wheel, support 52 and nut 66 towards the workpiece P at a rate equal to the reduction in radius of the grinding wheel due to wear and the action of the chopping tool. Rotation of the shaft 56 adds a further movement to the support 52 to feed the dressing tool 41 towards the grinding wheel, this additional movement, relative to the grinding wheel, being at the same rate as the movement of the grinding wheel towards the workpiece, the tool at the same time profiling the wheel under the control of the device 77, 79 and cam 82. Because of the portion 58 threaded in the opposite hand, the nozzles 70 move towards the grinding wheel at the same rate as the dressing tool but in the opposite direction. A hinged screen 107, which may be transparent, is positioned adjacent the wheel and chopping tool. Specification 847,411 is referred to.