| 摘要 |
<p>1330400 Perforating by drilling POWERS CHEMCO Inc 26 Nov 1971 [26 Feb 1971] 55070/71 Addition to 1265252 Heading B4B A device 102 for perforating sheet material, e.g. photographic film F, comprises a hollow drill shaft 111 mounted for rotation in a housing 104 and having a cutting end 140 adapted to pass through an air porous means 107 against a biasing means 136, 137, the housing defining front and rear vacuum chambers 129, 120 in communication with the bore of the hollow drill shaft, the arrangement being such that when a vacuum is applied to the rear chamber a suction is also applied to the front chamber thereby causing the cutting end of the drill to be forced against the film held against the porous means so that as the drill is rotated, a hole is cut in the film. The hollow drill 111 is held within a sleeve 110 provided with a pulley 134 and a piston 124, 125, 126 slidable in a cavity 119 formed in the housing 104. The drill is rotated by a motor 135 via a belt 136, the belt being trained over pulleys 137 such that the drill is urged axially away from the porous surface 107 as shown in Fig. 1. In order to drill a hole, suction is applied to the chamber 120, 129 thereby allowing atmospheric pressure to act on the piston via a groove 1 so as to force the drill into contact with the film. Upon rotation of the drill a hole is formed, the cut-out plug being drawn through the suction pipe where it is deposited in a container (151) Fig. 2 (not shown).</p> |
