| 摘要 |
1,224,931. Apparatus for pulling-open the ends of tube-section sheeting. WINDMOLLER & HOLSCHER. 11 April, 1968 [2 May, 1967], No. 17700/68. Addition to 1,179,735. Heading B5D. Apparatus for pulling open the ends of tube sections of plastics material sheeting as described in parent Specification, is characterized in that vacuum conduits leading to the vacuum beams are provided with valves which are disposed close to the vacuum beams and are automatically opened when the vacuum beams pass through the fully engaged position and remain open during the pulling-out operation. The vacuum beams 77, 78 are revolved in opposite senses and when the beams contact a flattened tube section 76, suction is applied and the beams, moving away from each other, open up the tube. Vacuum is applied via flexible tubing 105, 106, 107 to upper and lower stationary fittings 108, 109, each having a cylindrical extension 110 which extends through a circumferentially curved slot 111 to a valve disc 112. Each valve disc 112 is mounted for circumferential adjustment on a bearing 116 and is held against rotation by a pin 117. This adjustment determines the position of the vacuum beams at the beginning and end of the application of vacuum thereto. Each valve disc 112 is urged axially, by compression springs 120, into contact with a rotary disc 123 mounted on a shaft 124 and driven by the respectve vacuum beam through blocks 128. As each vacuum beam approaches the fully engaged contacting position, a circumferentially curved aperture 126 in the disc 123 registers with a vacuum bore 114 associated with the corresponding valve disc 112 so that vacuum is applied to the beam through tubes 127, 132 (the tube 127 being flexible). The vacuum continues to be applied to the beams until the aperture 126 ceases to register with the bore 114. The beams 77, 78 are relatively adjustable for different thicknesses of work material and the whole mechanism can be adjusted relative to a side frame 100 by a hand wheel 102 operating a screw 101 for dealing with different widths of material. |
