CUTTERS

摘要

The invention relates to cutters (1) for cutting connecting holes in plastics pipes (8). Predominantly the connection of a service to an existing plastics pipe is by way of an electro-fusible saddle (7) being located on and sealed to the pipe and the cutter introduced down the stem of the saddle to cut a hole in the pipe and thereby connect the pipe to a spigot or branch on the saddle to which a service line is connected. The cutting of the hole in the pipe inevitably results in leakage that can be dangerous when the pipe is carrying gas. There are constructions of cutter that attend to the question of leakage at the point that a hole is cut but which still have a leakage problem at the point that the cutter is withdrawn and before a cap is applied to the stem. The object of the invention is to eliminate this problem, which objective is met by a cutter construction comprising a cylindrical blade (2), a threaded body portion (3) attached to the blade, and there being an integral first length of rod or tube (4) on the body portion to the opposite side of the cylindrical blade portion together with a second length of rod or tube (15, 16) extending from an detachably attached to the said first length, the junction between the said first and second lengths serving as a visual indicator means. Thus, once a hole in the pipe has been cut the said second length maintains its contact with a sealing ring in the stem during the retraction of the cutter until the visual indicator confirms that the cutter has been fully withdrawn following which the exposed second length is removed without the aid of additional tooling with the seal maintained against the first length of rod or tube, the fitting of the cap providing additional security against leakage.