Patent GB-109256-A (GB)
Title: Improvements in Gear-cutting Machines.
Inventor: MAAG MAX
IPC: B23F5/14
Filed: 1917-08-08
Abstract: 109,256. Maag, M. Aug. 17, 1916, [Convention date]. Gear-cutting.-In cutting spur or helical wheels, the blank is rolled on a cutter in the form of a rack which is reciprocated in a direction parallel or at an inclination to the axis of the blank. The blank is carried by a table 19, Figs. 1 and 2, which can be rotated by a worm 20 feathered to slide on a shaft 21, and is traversed by a screw 11. The table 19 &c. can be adjusted to and from the cutter by a screw 8, Fig. 3, operated by a hand-wheel 5. The screw and worm are so operated as to produce an intermittent rolling movement while the cutter 104<a> reciprocates, then a continuous backward rolling movement, a backward traverse without rotation, a second backward rolling movement, and finally a continuous forward rolling movement to take up play prior to the first-described movement, which is then repeated. The cutter 104<a> is carried by a holder 98 pivoted, for relief during the return, to a slide 97 adjustably connected to a lever 91 by a link 94. All these parts are carried by a head 300 adapted to be angularly adjusted about the axis of the shaft 68<a>, Fig. 1, by a hand-operated worm so as to cut helical gears. The lever 91 is slotted to take a block 90, Fig. 3, on the pin 83, Fig. 1, which is adjusted across the face of a disk 82 by a screw 88, bevels 86, and a squared spindle 84. The shaft 68<a> carrying the disk 82 is driven from the main pulley 60, Figs. 2 and 5, through a clutch 61, bevels 64, and change-speed gearing 71, Fig. 1, controlled by handles 78, 79. Between the strokes of the cutter, and when it is not in contact with the blank, the blank is rolled forward by a slight rotation of the shafts 11, 21, the motion being derived from the shaft 68<a> through eccentric gears 120, Figs. 1 and 2, bevels 122, relief clutch 340, crank 124, slotted lever 126, adjustable block 127, ratchet gear 131, shaft 132, Fig. 5, gears 133, 134, clutch 169, Fig. 8, bevels 135, 137, change-speed gear 141<a>, shaft 26, one of the bevels 29, 30, Fig. 20, bevels 31, 33, 35, 34, and change-gears 54, to the shaft 21, and also from the bevel 31 through gear 51 and change-gears 53 to the shaft 11. The bevel 135 carries a gear 163, Fig. 8, which drives a drum 150, carrying cams A - - F, through gears 162 and a one-way ratchet gear 152. During the last cutting stroke, the cam E, Fig. 12, operates levers 210, 208 on the shaft 209 to lift the rod 207, Fig. 5, against its spring, thus turning the plate 204 about the point 252 to bring it within reach of the cam 206 on the shaft 68a, which, at the moment when the cutter is at its highest position, turns the plate 204 about the point 253, lifting the rod 254 against its spring. This action is made more certain by a catch 213 released by a lever 211 operated by the shaft 68<a>. The rod 254 turns the lever 222 in a clockwise direction, the arm 202 thereof being withdrawn from below the block 201 on the rod 196, which is moved down by its spring, thereby operating the lever 197, which releases the clutch 61 and applies a band brake 200 to stop the cutter. Also, during the last cutting stroke, the cam B, Fig. 12, throws the lever 179 past its mid-position, this position being unstable by reason of a spring toggle 181, Fig. 10, on the same shaft 180. The lever 179, acting through the lost-motion device 183, 184, moves the lever 185 through a distance limited by engaging a nose 187<a> of a lever 187. The lever 185 is arranged to operate the clutches 169, 170, Fig. 8, feathered on a sleeve of the gear 134 and on the shaft 140 respectively; but the limited movement only releases the clutch 169, thereby stopping the feed and the rotation of the drum 150. The rod 196, Fig. 5, however, operates the lever 195 and shaft 194 to move the lever 187, Fig. 10, towards the drum 150, thus releasing the lever 185, which, under the action of the spring toggle, closes the clutch 170. The shaft 140, Fig. 8, is constantly driven at a higher speed, but in the same direction, as the gear 134 has been intermittently revolving; by a belt on pulleys 173, 174, Fig. 2, and gears 175, 177, Fig. 8, so that when the clutch 170 is closed, the bevel 137 and all the gearing driven thereby is given a reverse movement and the blank is given a backward rolling motion. The drum 150 is now driven in the original direction through gears 165 and ratchet gear, Fig. 8, and its cam F, Fig. 12, moves the lever 178, shaft 27, arm 46, Fig. 21, spring pin 44, and lever 41, Figs. 19 and 20, which thus releases the frame 37 carrying the bevels 35, so that it rotates freely and the gears 54 &c. which rotate the blank become inoperative. The blank is therefore traversed without rotation. The earn F then releases the lever 178, the lever 41 again engages the frame 37, and the backward rolling is resumed. A recess in the edge cam D then comes opposite a bolt 188, Fig. 8, and this allows a spring to close the clutch 192. At the same time, the cam A, Fig. 12, moves the levers 179, 185 to release the clutch 170 and close the clutch 169, so that the bevels 135, 137 and the gearing driven thereby give a rapid and continuous forward rolling motion to the blank. The ratchet 131 meanwhile overruns, and all slackness in the drive is taken up. Then the cam D opens the clutch 192, and the cam C moves the lever 187, shaft 194, and levers 195, 197 into their original position to release the brake 200 and close the clutch 61. The catch 202 is now able, under the action of the spring 203, to move below the block 201, thus returning the parts 222, 254. The cam E has meanwhile released the lever 210, so that the rod 207 has moved down, all the parts resuming the position shown in Fig. 5. The plate 219 may be operated by a hand-lever 217, Fig. 2, to start or stop the cutter &c. manually. Either direction may be chosen for the forward motion, according to the position of the reversing. clutch 28, Fig 19, which is operated by a rack 47, shaft 50, and hand-lever 55, Fig. 3. The pawl engaging the ratchet 152, Fig. 8, may be held in an inoperative position by a pin 160 actuated by a handlever 158. The change-speed gear 141<a>, Fig, 8, is operated by a hand-lever 142, Fig. 1. The weight of the cutter slide is balanced by a weight 113, Fig. 3.