Patent GB-598909-A (GB)
Title: Improvements in automatic turret lathes and other automatic machine tools
IPC: B23B7/12
Filed: 1945-03-13
Abstract: 598,909. Lathes. POTTER & JOHNSTON MACHINE CO. March 13, 1945, No. 6319. Convention date, Jan. 20, 1943. [Class 83 (iii)] An automatic turret lathe or like machine tool having a timing-mechanism for synchronising the movements of a transversely movable tool-carrying slide with the movements of a longitudinally movable tool-slide is characterized in that the timing mechanism includes an exchangeable cam member removably attached to clutch-shifting means, and a removable timing-member adapted to carry manually adjustable and removable elements which may be selectively positioned so as successively to engage the clutch shifting means in order to engage and disengage the clutch periodically during a cycle of operations of the machine. The main feed shaft 13, Fig. 1, driven from the machine spindle 11 actuates the turret slide 14 through bevel gears 19, 20, worm gears 22, 23 and a cam drum 17. The turret 16 is indexed one face for each reciprocation of the slide 14 by mechanism not shown. The feed shaft 13 also drives, through timing- mechanism housed in the box T, a shaft 44 which in turn rotates a cam drum 28, Fig. 2, through worm gearing 45, 46, for feeding and withdrawing a cross slide 15. The timing- mechanism comprises a gear wheel 29, Fig. 3 (parts shown spaced-out for clearness) secured in driving rotation to the feed shaft 13, and meshing with a gear 37 freely rotatable on a sleeve carried by the shaft 38. The gear 37 drives a gear 53 which carries an index pin 54 for rotating a Geneva wheel 55 carried at the end of a short shaft 56. The other end of this shaft carries a pin wheel 57 with two pin " teeth " 59 spaced at 180 degrees. These engage peripheral teeth on a timing-wheel 58 secured to the side of a drum 47. The drum has holes 47a in its periphery, corresponding to the number of turret faces, to take the stud ends of roller tappet pieces 48. Additional openings 47b, Figs. 7 and 9, are provided in the drum to take guide studs 62. The latter ride along the side of a block 49 when the tappets 48 are not acting thereon. A cam groove 50 is provided in the block 49 into which the tappets 48 pass to reciprocate the block and the shaft 38 which is secured to it. A gear wheel 40 rotatable on but fixed axially to the shaft 38 has clutch teeth 40a, Fig. 3, on one face, which, when the shaft 38 is moved sufficiently to the left by the cam block, engage similar clutch teeth in the constantly rotating gear wheel 37. Gear wheel 40 is thus set in rotation and through the gears 41, 43 the shaft 44 is rotated for operating the cross slide. The gear ratios and Geneva gear &c. are arranged in the example described so that three operations of the cross slide are performed in one complete cycle of the machine thus employing only three studs 48 on the drum 47 although five holes are provided to correspond with the fivefaced turret 16. The block 49 and drum 47 with the timing-wheel 58 and pin wheel 57 are exchangeable so that the machine may be adapted for a different set of operations or for a turret 16 with a different number of faces. The gear wheel 29 may be disengaged from driving relation with the shaft 13 by slackening a nut 35, Fig. 3, this allows the spring 36 to push the wheel 29 to the left and disengage driving clutch faces 34. The machine may be hand-cranked in this condition to change the relationship between turret-slide and crossslide operation and the wheel 29 then brought back into driving relationship with the shaft 13. Specifications 288,340 and 301,757, [both in Class 83 (iii)], are referred to.