Patent GB-982229-A (GB)
Title: Truing mechanism for grinding machine
IPC: B24B53/06
Filed: 1963-10-15
Abstract: 982,229. Grinding. CINCINNATI MILLING MACHINE CO. Get. 15, 1963 [March 25, 1963], No. 40582/63. Heading B3D. A trueing device for a grinding machine comprises a trueing tool carrier 20, Fig. 1, carried by a support member 16 which is movable about a first axis A with selective means 43, 44 provided to restrain the movement, the carrier being movable relative to the support member about a second axis B, and a single drive member 30 engaged with the carrier sequentially to move the support member about the first axis until the support member is restrained and to move the carrier about the second axis after the support member is restrained, the drive member being operable at different speeds. A diamond-tipped tool 23 is adjustably mounted in the carrier 20 which is supported for rotation about the axis B by bearings 21, 22 on a shaft 19 carried by the support member 16 in turn mounted for rotation about the axis A by bearings 17, 18 in a housing 15. A depending portion 35 of the carrier is formed with a segmental gear engaging a bevel gear 34 on the single drive member which is in the form of a hollow shaft 30 supported in bearings 31, 32 in the housing, the shaft having a gear 67 keyed thereon and engaging a bevel gear 66 on a shaft 65. A shaft 36 depending from the support member 16 is disposed with clearance within the shaft 30 and has an arm 38 extending between stops 43, 44, stop 43 being carried on an upper cup member 40 and stop 44 being carried on a lower cup member 41. The cup members are angularly adjustable about the axis A and can be secured in position by clamps 51, 58; the angular position of the stops determines the amount of rotation of the support member before it is restrained. The depending portion 35 of the tool carrier is normally retained in a vertical, central position by spring-pressed blocks 70, 71, Fig. 2, bearing against a pin 68 on the portion, the blocks also acting on a pin 69 on the support member to resiliently hold the member in a central position. The housing 15 can be moved towards or away from the grinding wheel 11 by a screw 14 and is adjusted so that the axis A lies in the plane P of the wheel. If the stops 43, 45 are adjusted to abut one on each side of the arm 38 when the latter is extending towards the grinding wheel, i.e. at right angles to the position shown in Fig. 1, the support member will be prevented from rotating and rotation of the hollow shaft 30 upon rotation of the drive shaft 65 will cause the segmental gear portion 35 to rock about axis B so that the diamond moves in a substantially straight line to dress a substantially straight profile on the grinding wheel. With the stops 43, 44 adjusted to be 90 degrees apart, motion of shaft 30 causes rotation of the support member 16 through 90 degrees, the relative movement between the gears 34, 35 being resisted by the spring pressed blocks 70, 71 acting on the pins 68, 68, so that the diamond travels in an arc 100, Fig. 11a, to dress a curved portion on the wheel. Further rotation of the shaft 30 at each end of the 90 degrees movement with the arm 38 engaging one or other of the stops causes the gear segment 35 to be rocked about the axis B so that the diamond moves in a substantially straight line to dress the substantially straight portions 101, 102 on the wheel. The diamond can be adjusted in the carrier 20 to determine the radius R of the curve 100. With the diamond adjusted to a position from the axis A equal to half the thickness of the grinding wheel and the stops 43, 44 adjusted to the position shown in Fig. 3 to permit 180 degrees movement of the arm 38, the rotation of the shaft 30 causes the support and carrier to be rotated 180 degrees about axis A without rocking of the carrier about axis B to dress a circular profile on the grinding wheel. The drive shaft 65 connected by the gearing 66, 67 to the hollow shaft 30 is, at its other end, connected by gearing 95, 96, Fig. 6, to a pinion 93 engaging a rack 91 having a transverse follower 90 adapted for engagement with one or other of a pair of cam tracks 86a, 87a formed in cam discs 86, 87. The discs are secured to a member 85 carried on a splined shaft 82 connected by gearing 83, 84 to a reversible motor 80. The member 85 is movable axially on the shaft 82 by a handoperated eccentrically-mounted pin 89 to engage the follower 90 with one or other of the cam tracks. The shape of the cam tracks controls the rate of movement of the trueing tool during the trueing cycle, and one of the tracks may be shaped so that the tool swings rapidly during dressing of the arc 100, particularly if the tool point lies on the axis R so that the wheel is dressed with a V-shape, and moves more slowly during dressing of the straight portions 101, 102.