GB1332624A - Threading die head - Google Patents

Abstract

1332624 Threading die head GEORG FISCHER AG 14 June 1972 [14 June 1971] 27890/72 Heading B3N A threading die head comprises an annular die carrier 1, dies 2 mounted in radial slots in the die head, a slide bushing 6 threadedly connected to a flange 5 to which holding rods 4 are attached, cams 3 for controlling movement of the dies and a sensing pin 7 with an annular groove 10 therein; the slide bushing 6 has balls 11 mounted in slots 11a, the balls shown engaging in recesses 13 in the die carrier 1, springs 14 bias the flange 5 outwardly. In operation the die head is mounted in a thread cutting device by cams 22. When a thread has been cut the workpiece 8 engages an end surfaee 9 of the sensing: pin 7. The pin is thus moved relative to the slide bushing until balls 11 can move into groove 10. This releases the slide bushing such that springs 14 move flange 5 and thus rods 4 and cams 3 outwardly, the cams moving the dies into a disengaged position. Resetting is achieved by pushing pin 7 inwardly. Outward movement of the flange can be limited by screws that extend through the flange into die carrier 1, the head of the screw being offset axially relative to the flange when the parts are positioned as shown. Screw 15 prevents relative rotation between slide bushing 6 and flange 5. Spring biased ball 16 prevents accidental movement of sensing pin 7. Fig. 3 shows a modification wherein die carrier 1 includes a screw threadedly adjustable bushing 28 in which slide bushing 6<SP>1</SP> is mounted. A shoulder 33 on bushing 28 coacts with collar 34 to limit movement of pin 7<SP>1</SP>. Axial adjustment of bushing 28 controls the length of thread machined on a workpiece. A device 30 prevents rotation of bushing 28.