| 摘要 |
1,144,291. Lathes. CRI-DAN. 2 Sept., 1966 [3 Sept., 1965], No.39379/66. Heading B3T. A thread-cutting lathe comprises a saddle 3 movable against pressure means 26 by a roller 23 and a rotary cam 21 and a cross-slide 4 movable by a control unit 22, the cam having a recess 21c into which the roller may move except during a thread-cutting operation. A main spindle 12 is rotated by motor 7 which, through a clutch 14, rotates a cam drive shaft 16 which can be locked by a brake 18 under electromagnetic or electrohydraulic control. The saddle 3 and the bed 1 carry cylinders 26, 27 containing a common piston 28, 29, 30 which can be locked in either cylinder. The cross-slide 4 is fed inwardly against a spring 31 by the cam 22 actuating a lever 35 to advance a ratchet 39 and hence a cam 38 engaged by a follower lever 46. For boring and internally threading a sleeve P, a button 7a is pressed to start the motor 7 and a button V2a to operate a valve V2 to supply fluid to the cylinder 27 and feed the saddle 3. The roller 23 passes through the recess 21c and a dog T 1 on a panel PP attached to the saddle actuates a switch-unit B to operate a valve V 1 . The piston 29 then advances the boring tool 6. Finally, a dog T2 causes return of the saddle to the end of the travel allowed by the jack 26, thus preventing the roller 23 from entering the recess 21c. (In a modification, the recess is closed with a shutter.) The operator then replaces the boring tool with a thread-cutting tool and engages the clutch 14 by a buton 14a. The thread-cutting operation then ensues with the cam 38 determining successive depths of cut and the cam 21, now engaging the roller 23, determining the pitch of the thread. The cam works against the pressure in the cylinder 26. A disc R coaxial with the cam 38 carries a dog D to actuate a switch C at the end of the thread-cutting cycle. The clutch 14 is thus disconnected, the brake 18 applied, the piston 28 returns the saddle with the roller 23 passing through the recess 21a and the motor 7 is stopped. A similar saddle, cross-slide and tool may be provided on the opposite side of the headstock so that threads may be cut on each end of a long sleeve. The recess in the cam thus allows a sufficient retraction of the saddle to load the long workpieces. In a modification, the saddle is moved by an electric motor driving a rack and pinion gear. |
