| 摘要 |
<p>1278834 Punching TEXTRON Inc 26 Sept 1969 [26 March 1969] 47581/69 Heading B3W A coupon-retaining punch tool 46 for tapping metal members, particularly metal gas pipes, comprises a tapering head portion 55 having a bore 61 opening into its end face, an annular surface 76 surrounding the bore and edges 80, 81 formed at the junctions between surfaces 78, 79 (only 78 visible in Fig. 1) on the portion 55 and aligned with edges 90, 91 projecting from the surface 76. Shank portions 48 and 51 are interconnected by a tapered shoulder 50 and the shank portion 51 has a reverse taper of between 1 and 6 degrees, preferably 2 degrees. The punch tool 46 is a press fit in a holder 41 which is screwed into a T fitting 20 welded to a pipe 30. The holder is rotated by means of a wrench to advance the punch head and punch an opening 33 in the pipe 30, the tool 46 being guided by ribs 32. The shoulder 50 forms a seal with surface 34 formed on the pipe during punching. The coupon 70 punched out of the pipe 30 is retained substantially entirely within the bore 61 during withdrawal of the punch tool.</p> |
