Patent GB-1144161-A (GB)
Title: Grinding machines
Inventor: ADAMS ALFRED ENOCH
IPC: B24B41/00
Filed: 1965-06-22
Abstract: 1,144,161. Grinding. WICKMAN MACHINE TOOL SALES Ltd. 1 Aug., 1966 [22 June 1965], No. 26300/65. Heading B3D. A mechanism for controlling the relative movements of a pair of parts 18, 28, Fig. 3, of a grinding machine comprises at least two wedges members 23, 24, 25 disposed adjacent to one another and between a pair of inwardly presented surfaces 26, 27 on the parts of the machine respectively, and means for independently moving the wedge members transversely of the plane of relative movement of the parts to vary the distance between the surfaces to cause relative movement of the parts. As described, the mechanism is incorporated in a machine for grinding an internal cylindrical or conical surface but may also be incorporated in other types of grinding machines such as machines for grinding external cylindrical or conical surfaces. The machine has a grinding wheel 13, Fig. 1, driven by a motor 12 mounted on a slide 11 longitudinally movable on a bed 10. The workpiece 16 is carried by a chuck 15 of a workhead on a feed slide 18 reciprocable on a base 19 which is adjustable about a vertical pivot for permitting conical grinding. The slide 18 also carries a dresser 20. The movement of the slide 18 in a direction transversely to the movement of the grinding wheel is effected by the wedge members 23, 24, 25, member 23 effecting the feed and being movable by a piston and cylinder device 33, member 24 being movable by fluid pressure supplied to cylinders 57, 58 to effect backing-off of the slide during a working cycle to permit dressing of the grinding wheel, and member 25 being movable by an hydraulic ratchet device to move the slide an amount compensating for wear and dressing of the grinding wheel. The feed movement of the wedge member 23 is controlled by switches 36, 37, 38 actuated by the lobes 39, 40, 41, Fig. 6, of rotary cams connected by rack-andpinion mechanism 42, 46 to the wedge, the position of the cams being adjustable relative to the pinion 46 by gearing disposed between toothed rings secured to the cams and a member secured to the shaft 45 of the pinion. The retracting movement of the member 23 may be effected by an adjustable spring or hydraulic means. The back-off wedge member 24 is movable by means of fluid pressure supplied to the cylinders 57, 58. The wedge member 35 is movable by axial movement of a screw-threaded rod 66, Fig. 7, to compensate for wear and dressing of the grinding wheel, the rod being engaged by a nut 65 rotated in steps by a pawl 64 on a sleeve 63 formed with teeth engaging a rack 62 on a piston 61 movable by fluid pressure in a cylinder formed in a housing 60. A second piston 75, the stroke of which is controlled by an adjustable screw, is also formed with a rack engaging the teeth on the sleeve to control the compensating movement imparted to the slide. The position of the rod 66, and hence the dressed size of the grinding wheel, is indicated by visual observation through a graduated opening in the housing of a member 70 secured to the rod 66. The rod 66 can be manually adjusted by rotation of a hand wheel 68. The surface 26 engaged by the member 23 is formed on the slide 18, and the surface 27 on the wedge 25 is formed on a member 29 which is supported in a part 28 of the base 19 and urged by a spring 32 towards the surface 26. In operation, the grinding wheel is advanced at a rapid and then a reduced speed towards the workpiece and thereafter axially reciprocated as the workpiece is fed towards the grinding wheel by movement of the wedge member 23 first at a roughing speed and then is allowed to dwell. The wedge member 24 is then moved to back-off the workpiece and the grinding is retracted past the dressing tool 20. The wedge member 25 is moved by movement of the hydraulic ratchet to displace the slide 18 a distance corresponding to the effect of wear and dressing of the grinding wheel which is then returned past the dressing tool at a fast and then slow speed to the working position, the workpiece being advanced at a slow speed and allowed to dwell before the workpiece and grinding wheel are retracted. Rollers for reducing friction are provided between the wedge members and between the members and the surfaces 26, 27.