Patent GB-715116-A (GB)
Title: Processing apparatus for photographic films, plates and papers
IPC: G03D3/10
Filed: 1951-02-16
Abstract: 715,116. Photographic processing apparatus. HILLS, T. H. April 17, 1952 [Feb. 16, 1951], No. 3794/51. Class 98(2) [Also in Group XXX] The apparatus comprises a line of open topped tanks for holding developing, fixing and washing liquids, frames each for carrying one piece of exposed light-sensitive material, a continuously movable conveyer belt for moving the frames through the liquids in the tanks, and lifting. traversing, and lowering means between adjacent tanks for engaging and transferring the frames one at a time from one tank to the next, operation of the lifting, traversing and lowering means being initiated in each instance by the arrival of a frame at the point of engagement with the said lifting. traversing and lowering means. As shown, non-corrosive metal frames 9 to each of which is secured and X-ray film are placed in a developing tank 1 in a dark room so that the lateral arms 11 of the top bar of the frame rest on and frictionally engage inextensible endless belts 7 which are driven by pulleys keyed to the same driven shaft so as to travel along the lateral margins of aligned developing, fixing, and washing tanks 1, 2, 3. When the frame, which in general will not lie perpendicularly across the belts, reaches the far end of the tank, one arm will engage a stop which may be a fixed pin or a trigger 14 operating a microswitch so that the frame will slew round until L-shaped hooks 12 in it are positioned over the trough-shaped bar 15 of an inverted T which is then in its rest position close to the edge of the tank 1 and the other arm 11 engages a second stop in the form of a trigger 14 for a microswitch whereby the frame closes a circuit through this switch, or both microswitches which are series-connected, to a solenoid which opens a valve allowing compressed air to pass into the bottom of a double-acting cylinder 17. Consequently the piston 16 is raised and carries with it the inverted T and at the end of this stroke an abutment on it mechanically operates a valve on the framework of the machine to direct air to the end of the cylinder 18 further from the tank 1 causing it to move in the same direction as the belts 7 along its piston which is fixed to the machine framework and so moving a carriage, to which the cylinder 18 is fixed. along a fixed guide rail 20 and carrying with it the cylinder 17. At the end of this travel a further valve on the framework is mechanically operated by engagement of an abutment on the carriage to effect the downward travel of the piston 16 through the position shown to deposit. the frame in the fixing tank 2 with the arms 11 resting on the belts and to operate mechanically at the end of the down stroke a further valve on the framework to effect return movement of the cylinder 18 so as to return the inverted T to its rest position. During the movement between the two tanks, the film is sprayed with water from jets 48 in a compartment 4 having a drain trough 49, the jets playing during the horizontal travel of the film under the control of a solenoid operated by a microswitch closed by the frame 9. The frame then passes through the fixing tank 2 until it is engaged by a second transferring means (not shown), located within an aperture in the wall 6 of the dark room which is light-trapped by flushfitting panels covering it to within a short distance of the belts 7 and having on the centre line of the wall an upstanding extension 44 of the end wall of the fixing tank 2, so that the frame is moved into the washing tank 3. outside the dark room, the return horizontal movement of the inverted T being permitted by an appropriate aperture in the extension 44 closed by three over-lapping rubber flaps 46, 47. As the frames 9 approach the end of the tank 3. they are deposited on lateral guide rails 7b running the length of the apparatus just below the general level of the belts since at this point the belts pass below the surface of the water.