Patent GB-551135-A (GB)
Title: Improvements in apparatus for processing photographic films
IPC: G03D13/04
Filed: 1941-11-08
Abstract: 551,135. Photographic developing apparatus for roll films. CORNERCROFT, Ltd., and RYCROFT, N. Nov. 8, 1941, No. 14420. [Class 98 (ii)] Relates to apparatus of the kind in which the film is wound on a drum rotatable in a divisible liquid treatment tank, the drum being provided with a series of film supports extending between its flanges parallel to its axis, and said supports having projections spaced apart along their lengths which cause the film to occupy a helical path around the drum. According to the invention, apparatus for automatically winding the film on to the drum comprises a device having a traversing motion parallel to the axis of the drum at a speed correlated to the speed of rotation of the drum. The device may comprise a lead-screw, a film spool carriage in releasable engagement with the screw in order that as the screw is rotated the carriage, is traversed parallel to the axis of the drum, means operating through reduction gearing for rotating the lead-screw and drum, and if desired means for arresting such rotation when the carriage reaches the end of its traversing movement. As shown, the drum consists of a pair of discs or spoked members 2, Fig. 1, joined by film supports 3 spaced around their peripheries, and formed of liquid-resistant material such as stainless steel or non-metallic synthetic material which in the case of the supports 3 may be reinforced by a steel core. On the supports 3 are provided ribs or flanges 22 of V-section, which are offset axially on successive supports to provide a helical path for a film woundin the spaces between the ribs. The drum is detachably mounted in bearings 5, 8 in the lower half of a casing 4 closely fitting the drum, and having a hinged upper half provided with snap fastenings for securing it in closed position. Between the halves is seating as of sponge rubber to render the closed casing liquid and light tight. Liquid is introduced into the casing through a pipe 15 rendered light-tight during the filling operation by an enclosed zig-zag baffle 16. To secure the leading end of the film the end of one support 3 may be provided with a boss 27 having a filmreceiving slot 28 and a film clamping screw 29. To secure the other end a separate attachment device may be provided. Rotation of the drum may be effected by hand, or by electric motor operating through reduction gearing on a spindle 7 in driving engagement with the drum. The automatic film loading mechanism comprises a lead-screw 47, Fig. 6, mounted parallel to the axis of the drum in bearings 48 in extensions 49 of a band 17 embracing the lower part of the casing 4, which extensions also carry a parallel shaft 59 along which is siidable a carrier (not shown) for the film spool. The carrier releasably engages the lead-screw, either by means of a divided or half-nut, or by means of a peg engaging the screw thread. Co-ordinated rotation of the leadscrew and drum is effected from the electric motor through reduction gearing, and as the lead-screw rotates it traverses the film spool carrier along the shaft 59 so that the film is drawn onto the helical path of the rotating drum. An automatic cut-out in a casing 72 stops the motor when the carrier reaches the end of its traverse, and a hand operable switch 71 also is provided. This traversing device may be added for cleaning the processed film on the drum by adapting the film spool carrier to receive a wiper of soft material such as viscose sponge or cotton wool.