Patent GB-300619-A (GB)
Title: Improvements in or relating to automatic screw machines
IPC: B23B13/00
Filed: 1928-02-28
Abstract: 300,619. Brown & Sharpe Manufacturing Co., (Assignees of Rich, C. A.). Nov. 17, 1927, [Convention date]. Lathes.-Automatic screw-machines are provided with a magazine for stock bars and with mechanism actuated automaticaly when the bar under operation is used up to stop the spindle, release a bar from the magazine, feed it into the spindle pushing out the waste end, and restart the spindle. The usual tool-turret, stock chuck, and reciprocating-gripper feed are provided. As the end of the bar passes into the rear of the spindle a feeler finger 130, Fig. 4, drops, releasing a lever 134 pivoted at 136. The rear end of the lever rises, releasing a pawl 140 which ther engages a rack 138, set according to the number of pieces the length in the spindle will produce. The pawl is oscillated by the chuck-closing mechanism, and when the number of pieces has been produced the rack is fed far enough for a dog 152 to rock a lever 154, Fig. 5, on a shaft 156 with an arm 158 which advances a rod 160 under a lever 34 to hold the swinging stock stop 28 inoperative. The stop is normally oscillated by teeth 30 on its boss meshing with a rack 32 reciprocated by a cam 38. A second dog 162 carried by the rack 138 at the same time rocks a lever 164, Fig. 11, throwing out a clutch stopping the turret &c. feed motion. A trip finger 172 is at the same time tumbled by contact with the finger 130, and a cam 170 engages a lever 125, Fig. 7, rocking it to compress a spring 128, become latched at 182, and withdraw a pin 124 from a cam groove in a clutch yoke 120, Fig. 4. Springs 122 engage the clutch to drive a cam shaft having a spiral feed cam 78 and a lobed cam 80 controlling the magazine release gear. The cam 78 has a dwell permitting the cam 80 to act first. As soon as the cam 78 commences the forward feed the bowl 86 is removed laterally from the cam 80 so that the magazine release is reset and is not again actuated. The bowl 86 is mounted on an arm rocking on the feed slide 70 and carrying a second bowl 88 engaging one of a series of yokes 64 keyed to a shaft 60. Rocking of the yokes carries fingers 62 into the magazine to support all the bars except the lowest. which is then freed by the withdrawal of a bar 56 carried by a plate 57 mounted on the arms 58 of the yokes. The released bar drops into a supporting groove 52. The cam 78 then advances the slide 70, Fig. 2, carrying a plunger that engages the end of the released bar and pushes it into place in the spindle. The rocking of the shaft 60 also causes a. cam on the plate 57 to lift the finger 130 which is then supported, during the insertion of the bar. by the trip finger 172 brought into position as above described. On the return of the slide 70 after feeding in the bar a lever 190, Fig. 7, is cam-operated to trip the latch 182 and allow the spring 128 to return the pin 124 into position to disengage the clutch 120, whereon a spring plunger locks the cam shaft in a definite angular position. At the same time an arm 203, which has locked the lever 134 clear of the pawl 140, is withdrawn. The stock stop is released at the end of the extreme forward movement of the slide 70 by an adjustable dog 204, Fig. 2, which rocks a lever 206 linked to rods 210, 212. The rod 210 is connected to a lever 214 on the shaft 156 and so withdraws the rod 160. At the same time the rod 212 actuates the lever 164 to restart the machine. A spring plunger 222 carried by the feed slide 70 engages a lug on the rack bar to effect its return, the, plunger being bevelled to snap over the lug during the forward movement of the slide. An adjustable trip plate 228 retracts the plunger when the rack bar has been returned to the required position. Parts of the guide for the bars and of the bar 56 and plate 57 are removable to facilitate changing the feed tube in the spindle when setting up for a different diameter of stock, and to afford further facility the pivot of the lever 134 is a spring pin permitting easy removal of the lever.