GB491231A - Improvements in or relating to developing tanks for photographic roll-films - Google Patents

Abstract

491,231. Photographic developing- apparatus. ERSKINE, A..J. Feb. 25, 1937, No.5605. [Class 98 (ii)] A developing tank for roll films is provided with means for guiding and supporting the film in the space to be occupied by the developing solution, means for engaging the free end of the film and means operable from outside the tank for moving said engaging means around said guiding and supporting means so as to draw the film therearound and means may also be provided for separating the backing paper from behind the film. In the form shown Fig. 1 represents a tank a made of plastic material such as resin fitted with inlet c and light-tight cap d. The compartment g comprises a spool k of exposed film and a rotatable empty spool m and is fitted with a lid h. The spool compartment is fitted with a slot s and spring t for guiding the film. A plate u, Fig. 3, moulded with a spiral groove v on one side is adapted to rest in the tank a against one side thereof and a disc having a central boss y is rotatably mounted on a loose shaft z. The disc x is formed with a radially extending slot 11, Fig. 5, which constitutes a guideway for a slide-block 12 fitted with a peg 13 for moving in the groove v and with a slotted bar 14. Supporting rods 15 project from the opposite wall and are arranged in a spiral. These rods are preferably removable. A friction wheel 16 fitted with operating knob 18 engages the edge of the disc x. Backing paper is wound on the spool m, and the film passes through slot s and is engaged with the bar 14 and the lid d is placed in position. The knobs of both spool m and wheel 16 are now rotated so that the film is wound round the rods 15 and the backing paper round the spool m. Developing solution may then be introduced through inlet c. Stop pins may be placed at suitable positions at the end of the spiral v so as to arrest the movement of the bar 14 when the spool is unwound. The - spool m may be rotated by means of a spring or geared with the spool k so that the: rotation of a single handle 1.8 may effect the drawing of the film and removal of the backing paper simultaneously. The slit s may be furnished with rubber edges pressing together to form a water- @ight seal. The tank may be provided with means for rocking it and also with an outlet tap. In another form the bars 14 may engage with a spiral guide at both ends and draw the film around so as to engage its ends in a spiral groove. The backing paper may be led through a guide slit into a chamber where it will form a coil of its own volition. Reference has been directed by the Comptroller to Specificatlions 166,897 and 205,968, [both in class 98 (ii)].