Patent GB-279405-A (GB)
Title: Improvements in or relating to gear cutting machines
IPC: B23F5/12
Filed: 1927-09-14
Abstract: 279,405. Gleason Works, (Assignees of Head, E. C., Finsen, E., and Carlsen, L. 0.). Oct. 22, 1926, [Convention date]. Gear-cutting. - In a machine for producing tapered gears, either bevel or hypoid, the blank-supporting head is Angularly adjustable on the blank .support to position the blank in operative rotation with a pair of reciprocating tools and the blank support is moved in a direction perpendicular to the plane of operation of the tools for feeding the blank to the tools and withdrawing it from operative position for indexing. The feed and withdrawal movements are controlled by a cam having two grooves one of which is used for the roughing and the other for the finishing operation. The base 10 is provided with an upright 11 .carrying the cradle 12 in which are mounted tool slides 13 carrying the tools T which act alternately on opposite sides of a tooth. The tool slides move on arms 17, 18 which are pivotally mounted and are adjustable to cut .gears of different tooth angles by - means of a screw 21 and securing- bolts 23. The tool slides are each connected to a block 27 working in a member 28 which is reciprocated by adjustable crank mechanism 30 driven from the main pulley shaft 35 through a gear train comprising bevel gears 36. shaft 37. bevel gears 38. change speed gears 41, shaft 40, bevel gearing 42 and shaft 44. Provision is made for argular and axial adjustment of the blank-head for setting purposes. The axial adjustmet is effected by a pinion 51 operated from a stud 50 and engaging a rack 52 on the blank-head carrier 53. Angular adjustment of the carrier 53 to position the blank in the correct cutting plane with respect to the tools is effected either by hand or by a gear segment. In order to generate the teeth the blank is rotated on its axis and the tool cradle is moved in unison to represent the appropriate down-wheel movement. The blank rotation for this purpose is effected from the main shaft 35 through feed change-gears 61, Fig. 2, bevel gearing 66, and back shaft 68 which is arranged to impart a reversible drive to a shaft 69 which is connected through change gears 75, spur gearing 78, shaft 80, spur gearing 82, 85 to a shaft 87. The change-gears 75 form generating change-gears for the cradle movement while the gears 82, 85. form generating gears governing the ratio of the blank rotation to the cradle movement. The shaft 87 is connected through differential gearing with an aligned shaft 88 splined to a sleeve 90 which is connected through bevel gearing 91, vertical shaft 93, bevel gearing 96, inclined shaft 98, bevel gearing 100, teelscoping shaft 101, shaft 103, index change-gears 105 and worm gearing 104 to the spindle 16 carrying the blank B. The angular adjustment of the carrier 53 is effected about the vertical shaft 93 while the splined connection of the shaft 88 with the sleeve 90 permits the rectilinear feed and withdrawal movements of the blank support 14. The index change-gears 105 control the number of teeth to be cut in the blank. The corresponding generating movement of the cradle is, derived from the shaft 80 through a clutch 110, shaft 111, bevel gearing 113, inclined shaft 114, and worm 115 engaging a sector 116 secured to the cradle 12. The mesh of the worm 115 with its worm sector is adjustable by a screw. The cradle is guided during its movement by means of an arcuate V.guide 125 formed on the column 11 and coacting with a corresponding way on the cradle constituted by an arcuate rib 126 and a gib 127 secured by screws 128. After a single tooth space has been cut the blank is withdrawn and indexed. For this purpose the blank support 14 is guided on rails 130 and is actuated by a cam 131 provided with two ways one of which 132 is employed for the roughing operation and the other 133, for the Brushing operation. The cam is connected to the support 14 through a pivoted lever 134, and two followers are provided one for each cam, the followers being provided with rack teeth and being brought selectively into operative position by means of a hand-operated pinion 143. For the roughing operation the cam 132 is designed to give a gradual feed of the tools into the blank and then a quick withdrawal for the indexing movement. The generating movements of the blank and cradle are disengaged for the roughing operation. For finishing, the tools are quickly fed to full depth and then the generating roll takes place. The blank support is then given a further small feed movement and a second finishing cut is taken on the return roll after which the blank is withdrawn and indexed. The cam lever 134 is adjustably connected to a block 146 pivoted to a block in an arm 145, adjustably secured to the blank support 14, the block being adjustable to vary the extent of the movement of the blank support. The arm 134 is arranged always to be in the same position when the blank is in full depth cutting position and a positive stop is used to determine this position of the arm. The stop comprises a cylinder 155 secured to the frame 10 and having a plunger' 156, the plunger serving as a resilient stop for the down roll and the end of the cylinder 155 forming a positive stop for the return roll. On completion of a blank the blank support is withdrawn well clear of the tools to remove the finished work and to position a fresh blank. This movement is effected by means of rack and pinion gearing 162 actuated through reduction gearing from a hand-wheel 164. The support 14 is disconnected from the arm 145 to permit this movement and means are provided for reconnecting the arm and blank support in the same relative positions. The cam 131 is driven from the back shaft 68. During the cutting operation, the housing 185 of the differential gears is locked by a pair of pivoted stop levers 186, one of which coacts with a pawl 192 on the differential housing. On release of the pawl by its stop lever, the pawl engages a continuously-driven ratchet-wheel 194 which thus drives the differential housing to impart the indexing movement to the blank. The stop levers are tripped by a cam 198 driven from the shaft 68 and actuating a sliding rod 204 connected to a lever 207 which withdraws the stop levers 186, from their stop plates. The stop levers are returned after indexing by plungers 209. The rod 204 passes through an oscillating sleeve 205 actuated through segmental gearing 217 from a second cam slot in the cam 198. The sleeve 205 is arranged to operate through a rod 213, the clutches of the reversing-mechanism on the shaft 69 so that both the reversal and the indexing movement are controlled by the cam 198. The gearing controlling the primary operations of the machine is all mounted in a housing 65 which forms a detachable unit which can be removed from the machine and the various gear elements properly synchronized on the work bench. Each tool slide 13 carries an adjustable tool block 230 fitted with a clapper block 235 swinging about an axis 236. The tool T is secured to a plate by bolts 238 and is adjustable by a screw 239. The tool is held in adjusted position by plates 240, 241 and screws 242. The clappers are swung on the return strokes by means of bars 245 on the tool arms coacting with friction boxes 246 which slide on the bars and are connected by rods 247 and toggles 249 to the clappers. When the slide 13 reverses the tension on the friction boxes thus rocks the clapper to withdraw the tool. The friction is exerted by springs 253 and plates 254 lined with friction material. Each clapper box is made wedge-shaped at its free end, the wedge engaging in a wedge-shaped keeper 251 when the clapper is in cutting position so as to prevent chatter. In order to set a succession of blanks in the same relative position to the tools, the blank-spindle carries an adjustable arm 260 having a pivoted extension 261 fitted with a finger 263 engaging a tooth space in the blank, and having an indicating mark on its upper end. A ring 264 fixed to the blank spindle carries a frictionally mounted ring 266 provided with a lug engaging a projection 270 on the blank head. The lug comes into engagement with the projection just as the blank is to be indexed and the ring 266 takes no part in the indexing movement. A notch 275 in the ring 266 is engageable by a finger 274 on a pivoted member 273 adjustably secured to the arm 260. In operation a roughed blank is first correctly positioned and the finger 263 is set to a tooth space by adjusting the arm 260. The member 273 is then set so that its finger engages the notch 275 and is then clamped in position and the finger disengaged. These adjustments determine the blank setting with respect to the relatively stationary ring 266 and since this ring does not partake of the indexing movement it retains i:s position relative to the tools. When the next blank is positioned the arm 260 is unclamped, the finger 274 set to its notch 275, and the arm re-clamped. The finger 263 is then engaged with a tooth space and the blank rotated by hand until the indicator is correctly set. The new blank will then be in its correct position. Pumps for cutting oil and lubricating oil are driven from the main shaft 53 by bevel gears 285. A cam plate 290 secured to the cam 131 may be arranged to reciprocate a rod 292 connected to an automatic stop mechanism 293 to stop the machine after the desired number of operations. The stop mechanism may operate either an electrical switch for stopping the driving motor or a countershaft control lever. Some features of the invention are stated to be applicable to machines using other types of tools and to the cutting of curve'd tooth gears and spur gears.