Patent GB-1066908-A (GB)
Abstract: 1,066,908. Seaming non-metallic sheet material. SCHWEIZERISCHE INDUSTRIE GESELLSCHAFT. March 23, 1965 [March 24, 1964], No. 12134/65. Heading B5K. Welding apparatus compeises a material feed drive 4, 4a, Fig. 2 (not shown), to continuously feed material along a feed path between welding elements 5, 5a, 6, 6a to produce a continuous weld and means responsive to a failure of this feed drive to separate the welding elements from the material. In the embodiment shown for continuously welding longitudinal outstanding flanges 2 of a rectangular cross-section tube 1 of thermoplastic material, a strip of the material is fed from a spool (not shown) over or through a tube-forming device (not shown) and then on to a table 38<SP>1</SP>, 38<SP>11</SP>, Fig. 3a. Articles to be packed may be included in the tube during the shaping thereof. Rollers 4, 4a, 5, 5a, 6, 6a, Fig. 2 (not shown), grip, feed and weld the flanges 2. The rollers 5, 5a, 6, 6a are provided with interior electrical heater resistors. The rollers 4, 5, 6 are mounted on vertical shafts 8 driven at the same speed and each carrying a pinion 11 mounted in bearings 9, 10 secured to a fixed frame 7. The rollers 4a, 5a, 6a are mounted, so as to be movable towards and away from the rollers 4, 5, 6, on shafts 8a having pinions 11a to engage the pinions 11 and mounted in bearings 9a, 10a. The bearings of the shaft 8a of the roller 4a are mounted in a support 13, Fig. 1 (not shown), and the bearings of the shafts 8a of the rollers 5a, 6a are mounted in a separate box-shaped support 12. The supports 12, 13 are pivotable on a shaft 14 mounted in supports 15<SP>1</SP> secured to the frame 7. Two springs 18 each comprising several leaves are attached to the support 12 and two cams 19 fixed on a shaft 20 rotatable by a lever 22 act on their free ends to urge the lever 22 and the support 12 in an anticlockwise direction, Fig. 3a, to clamp the flanges 2 berween the rollers 5, 5a, 6, 6a. A catch 24 secures the lever 22 in the operating position of the apparatus. The support 13 is similarly held in the operating position by a lever 26 engaging a catch 29 and having a cam. 28 contacting a spring 27, Figs. 1 and 2 (both not shown). If the levers 22, 26 are laterally displaced to positions 22<SP>1</SP>, 26<SP>1</SP>, Fig. 1 (not shown), and disengaged from the catches 24, 29 the supports 12, 13 swing in a clockwise direction, Fig. 3a, so that the rollers 4a, 5a, 6a move away from the rollers 4, 5, 6. The support 13 can only be brought into its open position by manual operation of the lever 26 whereas the lever 22 may be automatically brought into this position. Upon interruption of the feed, e.g. if the rollers 4, 5, 6 cease to rotate, an electromagnet 30 is energized by a switch (not shown) so that an armature 31 is attracted to the magnet and swings a lever 33 about a pivot 34 in a clockwise direction, Fig. 1 (not shown), so that a projection 35 thereon disengages the lever 22 from the catch 24. The rollers 5a, 6a move away from the rollers 5, 6 and an arm 37 attached to a member 36 on the support 12 moves upwards to prevent the flanges 2 from adhering to the rollers 5, 6, Fig. 3b (not shown). The rollers 4, 4a remain, closed to hold the tube 1 in position 38<SP>1</SP>, 38<SP>11</SP>. In a modification (not shown), the rollers 4, 4a are placed after the welding rollers 5, 5a, 6, 6a. More than one pair of holding rollers and/or only one pair of heating rollers may be provided. Instead of the electromagnetic 30, mechanical, pneumatic or hydraulic means may be provided to move the lever 22 to the open position.