Abstract: An orbital vibration generator means comprising, in addition to a clamp 4, 5 for holding a pair of thermo plastic pipes coaxially and a pressurizing means 2, 3, 14 for bringing into contact under a pressure junction end faces of a pair of thermo plastic pipes 10, 11 held by these clamps, a crank shaft 8 having a shaft portion 8a and a crank portion 8b in which the axes of these shaft portion 8a and crank portion 8b are eccentric, a motor 6 for giving rotation to the crank shaft 8, a bearing 9 attached to the crank portion 8b of said crank shaft 8, and a orbital vibration clamp 13 holding pipe an end portion of a thermo plastic pipe, formed integrally with the outer ring of the bearing 9 to move integrally with said bearing.

Abstract: A method for applying a corrosion-protective coating, with a heat-shrinkable tube, to a joint between welded end portions of corrosion-protectively coated steel pipes, has a configuration comprising the steps of: preparing a coating implement having a releasant layer formed on the outer circumferential portion of the heat-shrinkable tube, and a heating layer formed on the outer circumferential portion of the releasant layer; positioning the coating implement so as to cover the welded portion of the joint and its adjacent portions; thermally shrinking the coating implement in a state in which the gap between the coating implement and the aforementioned portions is kept in a vacuum; and removing the releasant layer and the heating layer, whereby the aforementioned portions are corrosion-protectively coated by the heat shrinkage of the tube.

Abstract: In a joint between welded end portions of corrosion-protectively coated steel pipes, a heat-shrinkable tube is positioned so as to cover the outer circumference of a welded portion and the outer circumferences of its adjacent portions, and the heat-shrinkable tube is thermally shrunk in a state in which a gap between the heat-shrinkable tube and the aforementioned portions is kept in a vacuum so that the aforementioned portions are corrosion-protectively coated with the heat-shrinkable outer layer of the heat-shrinkable tube thus thermally shrunk.

Abstract: An electrically remote-controlled intra-pipe work vehicle is hydraulically actuated and is adapted to work with a lining equipment for lining interior of a branch pipe interconnecting with the main pipe in which the vehicle is positioned. The vehicle has a self-clamping mechanism to securely anchor itself at a work site in the main pipe and a tool actuating mechanism for angularly positioning and actuating the lining equipment. The lining equipment includes a lining material anchoring hydraulic press for pressingly hold an end flange of a tubular lining material, which is made of a fabric impregnated with a thermosetting synthetic resin, by an arcuate pressing plate. A counter hydraulic press counteracts the pressing force of the lining material anchoring press. A sealing tube having an electric heater element imbedded therein is sealedly bonded to an end of the tubular lining material with a bonding agent having a low melting temperature.

Abstract: A gas shield chamber for enclosing a welding joint of a pair of rails during the arc welding of the welding joint. A pair of side backing plates are each held in contact with the groove at one side of the rails within the chamber and the side backing plates are respectively movable independently of each other by a pair of drives having manual-powered operation change-over means. The ratio of respective flow rates of each shielding gas from respective injectors into the chamber is varied in accordance with the movement of the side backing plates. A pair of ground terminals of a welding power source are arranged on the sides of the rails.

Abstract: A gas-shielded arc welding apparatus automatically welds materials to be welded, such as rails or shape steel. The apparatus includes a gas-shielded chamber and a pair of side backing plates arranged within the chamber whereby the whole weld zone of the materials is gas shielded and a welding nozzle and shielding gas outlets are separated from each other. The apparatus also includes a welding apparatus proper and a control unit thereby performing the welding in a fully automatic manner.

Abstract: A pipe end cutting apparatus for processing pipes without variations in the angle of bevel and the root face thickness due to changes in the diameter of the pipes. There are provided a pipe clamping device for clamping the inside of a pipe, a rotary driving unit supported on the pipe clamping device, a feed unit for moving the rotary driving unit in the axial direction, and a control unit for controlling the rotary driving unit to rotate concentrically with the pipe. Processing tools for cutting the pipe end are mounted on the rotary driving unit through parallelogram links in such a manner that the processing tools are each caused to make a parallel movement in the radial direction of the pipe, while maintaining its cutting angle at a given angle with respect to the pipe end.

Abstract: A method for welding by a magnetically driven arc, which comprises placing two objects of welding in butt formation with a small gap between the end edges thereof to form a welding line; parallelly connecting a first electric circuit comprising the two objects of welding and a cable arranged on the surface side of the two objects of welding and a second electric circuit comprising the two objects of welding and another cable arranged on the back side of the two objects of welding to a welding power source; flowing a welding current through the first and second electric circuits to produce an arc in the small gap; moving the arc along the welding line under the effect of an electromagnetic force in the direction of the welding line, the electromagnetic force being produced by the magnetic flux of magnetizing coils provided near the end edges of the two objects of welding and welding current flowing through the arc; and changing the amount of welding current flowing through the first and second electric circuit