GB191319385A - Improvements in and connected with Daylight Loading Photographic Dark Slides. - Google Patents

Abstract

19,385. Donald, J. Aug. 27. Dark slides; envelopes, plate and like.- Relates to daylightloading dark slides and t o plate - envelopes therefor, of the type in which the envelopes consist of an inner rigid support for either one or two plates and an outer wrapper adapted to be pulled out by hand at the same time as the shutter of the dark slide to free the plate for exposure, and to be drawn back over the plate by the closing of the shutter, and comprises chiefly means for automatically moving the plate into register when the shutter slide is drawn out and for moving the plate out of register when the slide is returned, whereby friction is avoided. The inner support d for the plates P is provided with bent strips f to form a light-tight joint with the edges of the open end of the outer wrapper c, and is retained in position by the engagement of a projection or catch o at one end of the dark slide with a hole in a projecting tab g. The dark slide is provided with a hinged back b fitted with a sliding shutter p, the side edges of which have projections adapted to engage with projections on the side edges of the wrapper c in such a way that, when the shutter p is closed, the wrapper c is drawn back over the plate. In order to avoid excessive friction when the shutter p and the envelope are manipulated, the envelope normally rests loosely against supports away from the exposure position and is automatically pressed into the exposure position only when the shutter p is fully open. For this purpose, the shutter p carries a spring t<5>, which, when the shutter is near the limit of its outward movement, enters a recess t<4> and operates a sliding bar t<2> connected by a pin t<3> to a slotted plate t on a pin or projection q, which is thus partially rotated and caused to ride up on an inclined tooth s, so as to press the plate envelope against the front flange n of the dark slide, against the action of a plate spring s<1>. The other end of the envelope is adapted to be pressed forward by the engagement of a stud w on the shutter p with a spring plate v. When the shutter p is pushed back, the pin q is positively retracted, and the spring catch t<5> is then raised out of the recess t<4> by engagement with a projection on the back b.