| 摘要 |
1,179,735. Opening bag sections. WINDMOLLER & HOLSCHER. 17 May, 1967 [18 May, 1966; 24 April, 1967; 25 April, 1967], No. 22833/67. Heading B5D. Apparatus for pulling open the ends of tube sections 4 of plastics material sheeting which comprises two vacuum tools which revolve in opposite senses, is characterized in that the lower vacuum tool 2 has alternate crests and troughs which extend at right angles to the open edge of the tube section, the vacuum openings 10 of this tool being in the troughs and the vacuum openings 9 in the upper tool 1 being in registry with the crests in the closed position of the tools. The troughs may diminish in depth from a maximum at that side of the tool nearest the open edge of the bag section, and there may be two or more vacuum openings in each trough which may be selectively actuated as by connection to separate air lines or by valve means. Since the tube section is clamped by folding blades there is undesirable relative movement between the vacuum tools and the tube plies sucked thereagainst as opening proceeds. Further if the vacuum tools move at uniform linear velocity equal to the speed of advance of the tube sections, then there is a relative movement between the tools and the bag section as opening continues. To overcome these disadvantages the axes of rotation of the suction tools may be inclined, Figs. 7, 9 (not shown), and the tools may be driven at a non- uniform speed as through elliptical gearing, Fig. 10 (not shown). |
