| 摘要 |
928,819. Tapping; sockets. BURGMASTER CORPORATION. Nov. 29, 1960 [July 11, 1960], No. 40921/60. Class 83 (3). An attachment for cutting internal or external threads comprises a pair of coaxial oppositely-rotating drive members 27, 32, a clutch 51 for connecting one of the members to a tool holder 14, threads on the holder engaging threaded means 20 to cause the holder to advance, means 91, 97 for reversing the clutch when the holder has made a predetermined advance and means 91, 105 for placing the clutch in neutral when the holder has been withdrawn. The nut 20 and the tool holder part 14b are replaceable to enable different threads to be cut. The clutch 51 has a groove engaged by pins on a pair of yoke members 57, 58 connected by springs so that, when moved axially, they snap over-centre into positions of engagement. The tap 12 is moved downwardly by moving a starting lever 88 anticlockwise manually or by a solenoid 107 to snap the member 58 over centre and engage the clutch with the drive member 32. The clutch 51 is connected by a pin 93 with the central rod 91 which carries a further pin 100. When the tool has advanced to a predetermined depth, the nut 97 on the holder strikes the pin 100 and pulls down the clutch to reverse the tap. At its upper limit, the ring 105 in the holder engages the rod 91 and moves it upwardly to place the clutch 51 in a neutral position below its unstable central position. The spindle 18 may be one of several on a turret head 108. Sockets.-The tap is carried in a removable socket 14a. |
