Patent GB-798317-A (GB)
Title: Improvements relating to tool sharpening machines
IPC: B24B3/02
Filed: 1956-04-30
Abstract: 798,317. Grinding cutters. GLEASON WORKS. April 30, 1956 [May 12, 1955], No. 13209/56. Class 60. [Also in Group XXXII] A tool sharpening machine comprises a tool support 12, Fig. 1, and a wheel support 29 arranged to be relatively movable so as to provide both a relative stroking motion between jig tool C and wheel W and relative feed and return motions between them, power means to effect the stroking motion, spring-operated feed means controlled by a dash pot to effect the feed motion, a manually-operable member to effect the return motion of the feed means, and a manually-releasable latch to hold the feed means in returned position. The cutter C, Fig. 1, which is shown as a face mill cutter, is mounted on a spindle 11 indexable about its axis 13 in a head 12, which is adjustable about an axis 15 on a slide 14 reciprocable as shown by the arrows 17 on a cross-slide 18 on a frame 22. The conical abrasive wheel W is mounted on a motor-driven spindle 27, Fig. 2, in a support 29 which is journalled on a post 32 for oscillation about the vertical axis of the post so as to carry the wheel back and forth across the tooth being sharpened ; this oscillation is effected by a motor 55, Fig. 1, rotating a vertical shaft 56, Fig. 8, having an eccentric 57 oscillating a pitman 58 pivoted to a plate 61 which is connected to the support 29 and controlled by a roller 64 engaging an arcuate slot 63 in the plate. The feed motion of the support 29 is controlled by a cam 39 mounted on a feed shaft 41 for coaction with a rod 38 which is disposed inside the post 32 and supports a nut 45 screw threaded on a screw 46 arranged to support at its upper end the upper portion 52 of the support 29 ; the screw 45 may be rotated by a wrench applied to its upper end after release of a lock screw 53 so as to raise or lower the support and thereby correctly position the wheel W in relation to the cutter when setting up the machine. The feed shaft 41 is coupled to an aligned shaft 67, Fig. 3, which is provided with a segmental pinion 71 meshing with a rack 72 on a spring-urged plunger 73 which reciprocates in a cylinder in a hollow bracket 66. The plunger 73 is initially held in retracted position with the spring 74 fully compressed by a spring-pressed latch 81, and, when the latter is released by a hand lever 85, Fig. 1, is moved forward to either of two positions as determined by a hand-settable stop 75. The rate of motion of the plunger and therefore of wheel feed is controlled by dash pot means comprising metering passages for hydraulic fluid in the hollow bracket 66. As the plunger moves to the right in Fig. 3, a check valve 87 in the plunger closes and compels the displaced fluid to pass through a metering passage leading from a port 89 to a central opening 93 in the left-hand cylinder head 92 and thence through a central bore 94 and radial passages 95 in a screw 96 pivotally connecting a feed-rate selector valve 97 to the head ; the fluid passes from the passages 95 into the valve and depending upon the setting of the valve proceeds to the left-hand end of the cylinder through either of two adjustable metering orifices which are set for fast and slow movement, respectively, of the plunger. With the cutter C installed in the machine, and the plunger 73 retained in retracted position by the latch 81 so that the cam 39 positions the active surface of the wheel W slightly above the level of the cutter blade B to be sharpened, the cutter slide 14 is advanced towards the wheel and the latch 81 then released by the hand lever 85 whereby the advance of the plunger 73 rotates the cam and feeds the wheel downwardly into the blade B at a rate determined by the setting of the valve disc 97 and to an extent determined by the setting of the stop 75. At the end of the feed, the plunger 73 is withdrawn by a hand lever 69, Fig. 1, on the shaft 67 and each tooth B is similarly ground by successively indexing the cutter. Two cycles of operation are performed on each cutter, the first-a rough grind-being with the valve 97 providing a fast feed and the stop 75 a long feed stroke, and the second for finishing with the valve and stop providing a slower feed and shorter stroke.