Patent GB-812770-A (GB)
Title: Improvements relating to tooth cutting machines
IPC: B23F15/06
Filed: 1956-08-31
Abstract: 812,770. Copy-milling. GLEASON WORKS. Aug. 31, 1956 [Sept. 23, 1955], No. 26736/56. Class 83 (3). [Also in Group XXIII] A tooth-cutting machine, e.g. for making clutches, as described in Specifications 594,492 and 624,769, having a tool-support and a worksupport comprises a frame 20, Figs. 1 and 2, a sliding base 46, a swinging base 44 carrying one of the supports and movable angularly on the sliding base about a first axis 43 perpendicular to the sliding base movement, a lever 118, Fig. 3, fulcrumed to the sliding base on an axis 121 parallel to the first axis and having a cam-surface engageable with a cam-follower on the swinging base, a slide 111 reciprocable rectilinearly at an angle to the direction of sliding-base motor and having a straight guide surface extending in the direction of sliding- base motor, a follower 115 on the lever engaging the slide guide surface and means for reciprocating the slide. The machine comprises a frame 20 having transverse horizontal ways 21, Fig. 2, along which is adjustable a crossslide 22; this has means including an arcuate way 23 for a member 24 for angular adjustment about a vertical axis 25. Member 24 has horizontal ways 26 for a cohunn 27 on which is vertically adjustable, by a screw 30, a workhead 28 carrying work W rotatable on an axis 31 intersecting vertical axis 25 at right angles. The work-teeth are cut with a milling cutter C on a spindle 34 journalled about an axis 35 in a housing 36 adjustable, by a screw 81, Fig. 1, along ways 38, parallel to axis 35, upon a sector 39. This is supported by an arcuateway 41, Fig. 3, and a trunnion 42 for angular adjustment about a vertical axis 43 upon the swinging base 44. Base 44 is movable angularly about the same vertical axis 43 along an arcuate way 45 on sliding base 46. A maindrive motor 37 on housing 36 and having a brake 57 drives, through belts 55, 56, a shaft 48 in housing 36; the belts and pulleys are preferably toothed to eliminate slipping. Shaft 48 drives cutter spindle 34 through gears 58, 59. Splined to shaft 48 is a shaft 62 journalled in sector 39 and driving through bevel-gears 64, 65, a shaft 66 journalled about axis 43 in trunnion 42. Shaft 66 drives, through bevel gears 68, 69 a shaft 71 journalled in sliding base 46. Shaft 71 is splined to a shaft 73, Fig. 4, journalled in frame 20 and driving, through gear 76, change-gears 77 and gear 75, a shaft 74 journalled in frame 20. Shaft 74 drives, through bevel gears 85, 84, a vertical shaft 83 journalled in frame 20 and which drives cams 88, 92 through clutches 86, 89 allowing angular setting of the cams on shaft 83. Cam 88 is engaged by a follower 94, Fig. 5, on a slide 95 on frame 20 and is urged against cam 88 by a piston 98 in a hydraulic cylinder 99. A roller 101 on slide 95 engages a sine-block 102 to reciprocate base 46, the amplitude of reciprocation being varied by adjusting sine-block 102 about axis 103. Sine-block 102 is urged against roller 101 by a piston 106 in a hydrauliccylinder 105. A follower 109, Fig. 6, for cam 92 is carried by slide 111 superimposed upon slide 95, slide 111 having a key 112 in a keyway 113 in slide 95. Slide 111 has a guideway 114 containing a follower block 115, Fig. 3, pivoted by a pin 116 to a block 117. The latter is carried by the lever 118 fulcrumed on shaft 119, Figs. 3 and 6, on slidng base 46. Block 117 is adjustable on lever 118 by a screw 122 and is locked by a wedge 123 and screw 124. On the opposite end of lever 118 is a cam 125 engaging faces 126 of lugs 127 on base 44. Gear 75, Fig. 4, meshes either directly or through an idler reversing gear 132 with a gear 133 connected by a toothed coupling 135 (enabling work-spindle 29 to be brought into phaserelationship with cams 88, 92), to a shaft 134 driving a Geneva mechanism 163 through bevel gears 136, 137, and gearing 143, 145, 148, 152, shaft 154 and gear 155. During approximately one quarter of each revolution of gear 155 the driven disc 163 is advanced by one-half revolution; between acceleration and deceleration there is a drive at constant velocity resulting from gear teeth 158 meshing with gear 164 and the disc 163 is locked, when not rotating, by cam-actuated dogs. The disc 163 indexes the work spindle 29 through shaft 177, differential gear 179, gears 184, change-gears 186 and gears 189, 193. If gear 181 is held stationary, the work spindle remains stationary during the dwell periods between successive index operations. Mechanism for turning gear 181 during each such dwell period and then returning it to its original position, either just before or during the following index operation, comprises a cam 195 on shaft 154, driving a toothed segment 197 connected by gears 203, 207 to shaft 208. Cam 195 may be so formed that the work spindle is turned at constant or variable velocity for cutting helicoidal surfaces of constant or varying lead. To operate the machine with constant rotation of the work spindle, the cam-mechanism is removed and a gear 211 on shaft 154 drives a gear 212 on shaft 208; alternatively a gear 215 on shaft 154 drives a gear 214 on shaft 208 through gears 216, 213. When the work spindle is to have only indexing motion, shaft 208 is held stationary by a clamp. Operation.-For cutting symmetrical-clutch teeth, the machine is set up for intermittent tooth-to-tooth indexing of the work and depthfeed of sliding base 46 effected by cam 88. Shaft 208 is clamped against rotation and swing. ing base 44 is held stationary by a circular disc substituted for cam 92. Cutter-axis 35 is parallel to work axis 31. To produce helicoidal chamfers on the tops of the teeth, the above operation is modified by installing cam 195, which produces rotation of the work at the commencement of the cutter in-feed, a dwell while the cutter is fed into full depth and withdrawn, and a further rotation during the terminal part of the withdrawal. Another method of simultaneously producing two sides of chamfered symmetrical radial teeth involves intermittent rotation of the work for tooth-totooth indexing and, swinging of the cutter about axis 43, by cam 92, swinging base 44 in time with the feed-motion produced by cam 88. The swinging of the cutter is in the plane containing axes 31, 35. By varying the swinging relatively to the depth-feed, the tooth surfaces may be given the desired profile shape, including a top chamfer. Saw-tooth clutches may be cut with a cutter 243, Fig. 18, or a disc-cutter 244, Fig. 19; the cutter has a curved edge 245 and a straight edge 246. The cutter is fed depthwise relative to the work by cam 88 and is rotated about axis 43 by cam 92 in time with the rotation of the work about axis 31 effected by cam 195; at the conclusion of such action the cutter is withdrawn by cams 88, 92, from the work, which is then indexed. In order to quickly clear the cutter from the work prior to indexing, cam 195 may reverse the workrotation at the conclusion of the cutting of the surface 241. Specification 775,716 also is referred to.