GB871673A - Film support for photomechanical camera - Google Patents

Abstract

871,673. Photographic apparatus. POWERS CHEMCO Inc. Nov. 9, 1959 [May 7, 1959], No. 37981/59. Class 98(1) An upright vacuum board for a photomechanical camera comprises as shown a face plate 10 having closely spaced holes 12 therein, a suction distribution manifold 20 which is connected by way of conduit 30 to means for producing suction, and two intermediate plates 14, 18, plate 14 of which is characterised by a rectangular opening 32 accommodating a rectangular apertured plate 34, slots 46 radiating out from the opening 40 formed between plates 14 and 34, and! grooves 48 between slots 46 in the lower part! of the board only, and plate 18 of which is characterised by openings 42, 44, 52 and 60 for connecting the various chambers and channels formed by the openings, slots, and grooves in plates 14 and 34 to the suction manifold 20. The total cross-sectional area of the channels 46 radiating out from chamber 40 is equal to the. total area of the openings 44, and channels 48 and the lower portions 54 of channels 46 have a cross-sectional area approximately half that of the upper portions of channels 46. This arrangement, in which the main suction is applied to the upper central region, ensures that suction losses even with small sheets of material, are small and that no wrinkles are formed in the said sheets. Ribs 24 in manifold 20 are provided for rigidity and to enable the other plates to be secured to the said manifold by means of screws 21.