Patent GB-769146-A (GB)
Title: Improvements in or relating to copying grinding machines
IPC: B24B17/00
Filed: 1955-05-06
Abstract: 769,146. Grinding; trueing grinding wheels. BLASI, F. May 6, 1955, No. 13224/55. Class 60  A grinding machine comprises a support 32 which is guided for movement relatively to a grinding wheel 17 in two perpendicular directions and is arranged to carry both the work piece 43 to be ground and a device 47 provided with diamond points 49 for trueing, respectively, the periphery and sides of the profile of the grinding wheel, a second support 62 which is similarly guided for movement in the same two perpendicular directions and is adapted to carry a master work pattern 71 and a trueing feeler 74 having points 83 located correspondingly to the diamond points 49, a pantograph designed to ensure corresponding movements of the two supports 'but at a pre-determined reduced ratio of the first support relatively to the second support and a device 54 constituting a feeler for co-operation with the work pattern 71 for the grinding operation and shaped with a profile corresponding to that of the grinding wheel so as to serve as a pattern for co-operation with the points 83 of the feeler 74 for the trueing operation. In an alternative arrangement, the two supports 32, 62 are fixed and the pantograph control is provided between slides carrying the grinding wheel and device 54. The machine is described as applied to the grinding simultaneously of two workpieces 43 by two grinding wheels 17 on a shaft 16 carried at one end of a casing 10 which is pivoted centrally on a support 4 movable longitudinally along the machine bed 2 by rack-and-pinion gearing operated by a hand wheel.5; the wheels 17 are driven through a belt-and-pulley drive 15 by a motor 13 at the opposite end of the casing. A link 23 pivoted to the support 4 engages an eccentric 22 on a shaft 19 which is rotatably mounted in the casing and may be clutched for drive by the motor 13 through a pulley 12 in the belt drive 15 and gearing 11, 18 so that the casing may be oscillated about its pivoted axis. The workpieces 43 are carried for operation upon by two wheels 17 by two holders. 40 clamped to the opposite ends of a support plate 36 mounted on a compound slide consisting of an upper slide 32 guided for movement transversely of the bed 2 by ball guides on a base slide 28 which is similuarly guided for movement longitudinally of the bed. The support plate 36 is mounted between end plates 33 on the slide 32, being guided in arcuate slots 34 in the end plates so as to permit it to be adjusted about an axid parallel to, and at the same level as the common axis of the grinding wheels. A stop screw 44 provided at each end of the support plate 36 permits correct location of the corresponding work holder 40. Also mounted at each end of the slide 32 is a post carrying at its upper end a pivoted arm 47 which is provided with the three diamonds 49 and may be swung from its inactive vertical position to its active horizontal position in which the diamonds engage the periphery and sides of the corresponding grinding wheel profile. The work pattern 71 and trueing feeler 74 are clamped to a carrier 70 which is mounted for angular adjustment between two handoperated screws 69 in a bracket 68 upstanding from the lower member 62 of a compound slide mounted beneath the bed 2; the member 62 is guided for movement longitudinally of the bed by two endless sets of balls on an upper slide movable transversely of the bed between ball guides. The pantograph connected between the slides 62, 32 consists of links 76, 77 between the slide 62 and bed 2 and links 79, 80 between the slide 32 and links 76, 77. The device 54 comprises three superposed feelers 54, 55, 56 which correspond to the profiles of the grinding wheels used, respectively, for rough grinding, pre-finishing and final finishing and are mounted in a slide 51 arranged to be adjusted vertically in the bed 2 by a hand wheel 53. In operation, the grinding wheels 17 for rough grinding are first trued by adjusting the carrier 70 to set the trueing feeler 54 for co-operation with the feeler 74, and the arms 47 to bring the diamonds 49 into dressing relation with the wheels 17; trueing is effected by successively guiding the two oppositely-facing points 83 of the feeler 74 over the corresponding inclined flanks of the feeler 54 and then moving the central point 83 around the tip of the feeler 54. After rocking the arms 47 into inactive position and adjusting the carrier 70 to set the work pattern 71 into horizontal position, as shown in Fig. 2, grinding of the workpieces is effected by moving the pattern 71 so that its contour tracks over the tip of the feeler 54. The operation is repeated using the feeler 55 and the prefinish grinding wheels instead of the rough grinding wheels; and then with the feeler 56 and the final finish grinding wheels, When.the-workpieces are lathe tools having clearance angles the support plate 36 is adjusted in the arcuate guides 34 so that it occupies an inclined position indicated by a scale 86 and the master pattern 71 is inclined at the same angle between the screws 69 as indicated by a scale 87. An accessory permitting the grinding of a rotary workpiece consists of a plate adapted to be bolted to the support plate 36 and supporting a rotatably-mounted work spindle together with a drive motor connected to the same through reduction gearing; when using this device, the means for oscillating the casing 10 about is pivoted axis are diengaged and the casing fixed in position.