PROCEDE, OUTILS ET APPAREILS POUR FORMER UN TROU DANS UNE CANALISATION

摘要

1297417 Drilling pipes MUELLER CO 15 Oct 1970 [21 Oct 1969] 49043/70 Heading B3C [Also in Division F2] In a method of tapping a live metal or plastics main 12 Fig. 1, a fitting 10 is at least temporarily secured to the main, and a tool 11 having a screwed tapered portion 52 is rotated and moved through a bore 38 in the fitting and into hole-forming engagement with the main, the rate of axial feed of the tool being different from the lead of the screwed portion 52, whereby the material 62 Fig. 2 moved by the tool in forming the hole, is axially directed by the thread. The fitting 18 may be clamped to the main, or it may be welded thereto. The screw thread on the tapered end of the tool has a lead which is greater than the lead of the screw thread on the body portion 44 of the tool. A tapered portion 50 on the tool forces the material 62 around the hole 43 in the main and locks it to fitting 10. Tool 11 may be coated with a dry film lubricant on all surfaces except portion 50. A plastics service tee fitting (10), Fig. 4 (not shown), may be connected to a plastics main (121), the tool 111 Fig. 5, has a trepanning cutting edge 57 for removing a coupon S from the main, and a metallic ring 61 is loosely fitted on to the tool so that after the hole has been formed in the main, the up set material (621) Fig. 6 (not shown), is reinforced by the ring. In a modification, the fitting comprises a gate valve 78 Fig. 7, and the tool comprises a shell cutter 80 Fig. 8, having a pilot drill 92, and the tool is driven by a drilling machine 84 Fig. 7, connected to the gate valve. In a further modification, the fitting 10111 Fig. 10, is clamped to the main, and is screwed into a gate valve 112, which also has screwed thereto a manually operable drilling machine 118, for rotating and feeding the tool 11111. The tool is rotated and fed axially by rotating a screwed sleeve 128 and a rod 136 screwed together at 142 by a handle 130, with valve 112 open until the hole is produced in the main. Valve 112 is then closed, the drilling machine and tool are removed from the valve, the tool is replaced on rod 136 by a plug 116, body 120 is reassembled on to valve 112, which is opened, and the plug. is screwed into base 38111. The valve may then be removed.