Patent GB-403285-A (GB)
Title: Improvements in metal cutting and like machine tools
IPC: B23P15/52
Filed: 1933-05-03
Abstract: 403,285. Automatic lathes. WILT, A. D., New Canaan, Fairfield, Connecticut, U.S.A. May 3, 1933, No. 12930. [Classes 83 (ii) and 83 (iii).] Making taps, drills, and reamers; milling; chucks.-A lathe or like machine tool for making taps, twist drills, reamers, &c. has a fixed tool carrier provided with a number of spaced tool stations and coacting with a reciprocating indexable work turret fitted with rotatable spindles, a cam shaft with automatic speed control being arranged directly to effect the approach and withdrawal of the work turret and to control means for rotating the work spindles at predetermined times. The frame 10 with a drip pan 11 carries a gear box 14 for the main driving mechanism, and a fixed toolhead 15 carrying tools coacting with each of the five work-spindles 16a-16e the latter being mounted in an indexable and reciprocatable turret 16. The machine is driven by a motor M chain-geared to a shaft 20 connected by worm gearing to a shaft 21 which is coaxial with a shaft 21a connected through change gears 25 and worm gearing 27 to a shaft 29. This shaft drives through spur gears 63 and splined connecting sleeve 83, a central shaft 113 which has an outer bearing 13 in the frame. The shaft 29 is also connected through external change gears 31 with the main cam shaft 35. The shaft 21 carries a splined clutch collar 36, Fig. 5, operated through lever mechanism from a cam 49 on the main cam shaft. In the right hand position of the clutch, Fig. 5, the shaft 21a is driven at reduced speed through back gears 40, but in the left hand position the drive is transmitted direct through the clutch teeth 42 to the wheel 41 fixed on the shaft 21a. The bar stock feed mechanism is supported in the tool-head at the operating station 15a, Fig. 20. This mechanism is actuated from a cam 67 which operates a lever 61 coacting with adjustable stops 59, 60 on a rod 54, the spacing of the stops serving as a variable lost motion connection to vary the extent of movement of the rod 54. The rod reciprocates a block 56 carrying a sleeve 68 enclosing a rotatable sleeve in which is mounted a feed tube 71 fitted with a gripper 74 which feeds the stock bar 72 through the collet chuck 77. The chuck sleeve 79 terminates in a hardened collar 80 coacting with actuatingrs finge 102. The feed tube is slidably keyed in a sleeve 81 which is itself keyed in a short sleeve 96 having gear teeth at 97 by which the sleeve assembly and feed tube are rotated from a pinion 244 concentric with the shaft 113. The fingers 102 are mounted in the sleeve 96 and are actuated through a collar 104 mounted in a slide block 106 reciprocated through a lever from the cam 67. As shown in Fig. 33, when the feed movement occurs, a length of stock which has a reduced part 111 formed by a tool 114 is pushed into the chuck 138 of the work spindle 16a. The collar 104 then moves to the left to close the chuck 77 and the feed tube is returned. After completion of the feed, the work piece is cut off by a tool 112 and the next piece is grooved by the tool 114. These tools are fed by a lever 118 operated from the main cam shaft. The bar is supported aganst the cutting pressure by a roller steady 126, Fig. 20, adjustably mounted on a stud 125 secured to the tool head. Each chuck of the spindles 16a-16e consists of a tube 128 enclosing the jaw carrying member 130 which terminates in a hardened collar 131 coacting with the actuating fingers 132. The tube 128 fits in a bushing 135 mounted in the head 16 and a ball-thrust bearing is provided at 136. A pinion 139 meshes with a central gear 140 for rotation of the chucks. The fingers are actuated by a sliding collar 147 controlled by a yoke 150 pivoted to a retaining plate on the turret. An ejector pin 160 mounted within the spindle is normally held withdrawn by a spring 162 but may be moved forward on withdrawal of the turret to eject the finished work at the station 16e by a stationary cam 143. The chuck at this station is opened to allow the ejection by the engagement of its yoke with an abutment 397. A tray 405 is automatically moved to a position where it may receive the finished tap. When, after ejection of a work piece, the chuck 16e is indexed to the station 15a, a cut away part 406 of the yoke 150 is positioned to co-operate with a projection on a sleeve 409 which is moved axially by a cam 419 and lever 416, thus actuating the yoke to close the chuck on to a fresh blank. At this instant the cut-off tool completes the severing operation and the turret is then moved back with the fresh blank. The turret 165, Fig. 11, is mounted on central ball bearings 166 in a casing 168 which may slide on parallel longitudinal guide rods 169. A front cover plate 170 is provided. The casing carries a roller actuated by a cam 171 to reciprocate the turret. The outer surface of the turret has gear teeth 174 engaged by a pinion 175 forming part of the indexing mechanism. In the cycle of operations for making a tap, the work is rotated on its axis 90‹ between successive indexed positions. The work stations are 72‹ apart and the two-to-one gearing between the normally stationary central gear 140 and the chuck rotating gears 139 causes the work to rotate 144‹ during indexing. This is corrected by a clutch-controlled reverse blank rotation of 54‹ which takes place during the thread milling operation at stations 15d and 15e after the grooving cutters have completed their cut and are clear of the work. The hub of gear 140 carries clutch teeth 222 and also has an extension 424 which carries a grooved member 425 which coacts with a braking pin 427 to hold the gear 140 stationary while the turret is being indexed at its right hand position. Indexing is effected by the pinion 175 driven through a clutch and spur gearing 187 from a wheel 190 carrying rollers 195 of a Geneva mechanism, Fig. 16. A disc 197 on the main cam shaft has a projection with a triangular driving plate 198 which is spaced from an annular portion 201 by ingress and egress slots 202, 204 respectively of the mechanism. The plate 198 rotates wheel 190 through one third of a revolution to index the turret through the required angle. The turret is normally locked by a bolt 218, Fig. 17, which is withdrawn for indexing when the turret is fully withdrawn from the tool head by a rod 212 carried by lever arms 211 operated by a cam 205 on the main cam shaft. In order to effect the reverse rotation of the work spindles through 54‹ so as to obtain a net rotation of 90‹ between successive stations the clutch teeth 222 of the gear 140 co-operate with teeth on a sleeve 225 splined on the central drive shaft. This clutch is engaged and disengaged at the required times to effect the necessary movement of the tap blanks by a lever 226 operated from a groove 228 of the cam 124. In a modification the clutch teeth 222 are formed on a sleeve which is splined in an extension of the hub of the 3ear 140 so that the clutch controlled blank rotation may be effected in any axial position of the turret. The tool head 15 carries the blank feed mechanism at station 15a, pairs of oppositely disposed milling cutters for cutting opposed flutes at 15b and 15c, and pairs of thread milling cutters at 15d and 15e. The left hand side of the tool head carries the mechanism for driving, feeding, and withdrawing the cutters. After positioning a fresh blank at station 15a the turret is withdrawn indexed and then moved to the left for the first machining operation by the tools 227, 228, at position 15b, Fig. 20. The cutter 227 is keyed to a taper mandrel and is driven by worm gearing 235 actuated by the loose central gear 244. The housing 234 of this cutter is adjustably mounted on a sleeve carried by the main toolhead casting 243, and the sleeve carries a quadrant 250, Fig. 19 having teeth meshing with a central gear 251 keyed on a sleeve mounted on the central drive shaft 113. The gear 251 is rotated by a cam 257 and lever mechanism to bring the fluting cutters up to the work when required. The shaft 20 carries a gear 256 connected, Fig. 22, with the gear 244 on the central shaft, this gear train serving to operate all the rotary tools. The fluting cutters 227, 228 pass through slots in a tubular member 257a, Fig. 28, mounted in the tool head to support the blank during the cut. Oil from a pump 289 is supplied to the cutters through a pipe 259. All the fluting cutter are similarly mounted on their spindles. The cutter 262 at station 15c and cutter 228 at station 15b have a common pivotal point 265, and are driven from a common worm operated by the central gear 244. The housings of the two cutters 228 and 262 are adjustably connected together and the quadrant 274 which moves the cutter housings to and from the work is operated synchronously with the quadrant 250 from the gear 251. After leaving the station 15c both sets of grooves have been cut in the blank as shown in Fig. 34a. At the end of the working stroke of the turret to the left, the turret is arrested and the blanks are free to revolve for the thread-milling operation. The cutters employed consist of a number of circular rows of teeth without lead, the work being rotated during the operation and the cutters fed axially according to the pitch required. Two opposite thread portions are cut at station 15d by thread mills 292, 294, Fig. 20, and the remaining thread portions at station 15e by thread mills 295, 296. The cutter 292, Fig. 21, is mounted on a taper spindle 301 and carries a pinion 302 driven from the pinion 258 of the cutter driving train through a gear 304 which also drives all the other thread milling spindles synchronously. The cutters 292, 295 are mounted in arms 306, 312 respectively, the arms being relatively adjustable and being operated in unison by means of a quadrant 316 actuated by a pinion 319. The cutters 294 and 296 are mounted in a similar manner and are moved together to and from the work by a quadrant 325 actuated by a pini