| 摘要 |
<p>1,226,302. Suction lifting heads. RAPISTAN Inc. 5 Dec., 1969 [6 Dec., 1968], No. 59520/69 Heading B8H. A suction lifting head, Fig. 2, in which loads are held against a grate 14, Fig. 1, having a plurality of apertures 22, has independently operable valve means, which are biased into an open. position and arranged to close when a predetermined pressure differential exists across them. Suction is provided by an electric fan 13 and the grate 14 is attached to the lifting device by clips 15. Some of the spaces 31 are filled with impermeable material, such as foamed rubber, which projects and forms a seal against the load. The valves 40, Fig. 4 (not shown), are made of thin resilient strip material and are attached to a backing plate 34 by clips 43. Excess pressure flattens the valve against the backing-plate and closes an orifice 35. The valves need not be arranged in the pattern shown in Fig. 1, any suitable arrangement may be provided to accommodate articles of different sizes with or without gaps between them. To facilitate changing the pattern, the grate may be made up of subsidiary sections which can be arranged within the main frame when it is disconnected from the lifting head.</p> |
