| 摘要 |
<p>1,274,098. Seaming non-metallic sheet material. RAMSEYER & CIE S.A. 10 Oct., 1969 [10 Oct., 1968], No. 49927/69. Heading B5K. A tool for welding together pieces of plastics material comprises movable means 5, 6 for gripping two pieces 3, 4 of the plastics material which are to be welded together, heating means 12 adapted to be held between the pieces 3, 4 and to melt a part of each piece, means for retracting the heating means 12 from between the pieces 3, 4, and means for separating parts of the gripping means 5, 6 to actuate the retracting means and for bringing together the parts of the gripping means so as to press the pieces 3, 4 into welding contact. The tool comprises a pair of pincers hinged at 20 and comprising arms 1a, 1b, 2a, 2b. Preferably, a spring (not shown) is provided to constantly urge the pairs of arms apart. Each arm 1a 1b carries a semi--cylindrical gripping part 5, 6 which together define an aperture 7 corresponding in cross-sectional shape to that of the pieces 3, 4, e.g. circular, square, rectangular or trapezoidal. The parts 5, 6 are carried by interchangeable mountings 8, 9 hinged at 10 and fixed in their operative positions by two nuts with knurled heads 11. The heating element comprises a blade 12 formed with slots 22 which co-operate with pins 24 on a plate 23 on the arm 1b to limit sliding movement of the blade lengthwise of the pieces. In operation, the two ends of the pieces 3, 4 are introduced into the aperture 7 and the nuts 11 tightened. When the pincers are closed, the blade 12 is maintained between the ends by a pin 13 on the arm 1a co-operating with a hole 25 in the blade. While the end 12a of the blade is between the ends of the pieces 3, 4 it is heated by low voltage current supplied through cables 21 and melts parts of the ends by radiation. A slight opening of the arms la, 1b removes the pin 13 from the hole 25 and a spring 14 retracts the blade 12. The arms 2a, 2b are pressed together so as to bring the melted ends of the pieces 3, 4 into contact. Over compression is prevented by an abutment 27 on the arm 2b. The pieces 3, 4 may be the two ends of a single length and are welded to form an endless loop, e.g. a driving belt or an elastic packing ring. In a modification, Fig. 3, the ends of the pieces 3, 4 are cut, prior to introduction into the parts 5, 6, to provide mating surfaces for welding, by a blade 15 mounted on an arm 16 pivoted by a pin 17 to a projection 18 on the arm 1a. The arm 16 normally clips against a member 19 on the arm 2b.</p> |
