Patent GB-699654-A (GB)
Title: Improvements in or relating to stereoscopic photographic cameras
IPC: G03B35/10
Filed: 1951-05-07
Abstract: 699,654. Stereoscopic photographic roll film cameras. SAMOGGIA, A. May 7, 1951, No. 10715/51. Classes 98 (i) and 98 (ii). A twin lens stereoscopic roll film camera having a reflector behind each lens directing the images to a pair of apertures in a central chamber across the walls of which a film is fed, has stop means actuated by a film measuring roller and adapted to prevent operation of film advancing means after a predetermined film length has been fed, and means operatively connecting the film advancing means to the shutter setting mechanism so that the film feeding operation also effects setting of the shutter. As shown, the two views received by the objectives O are reflected by the mirrored prism surfaces A to form on the film Z, which is pressed by plates P against apertures in the U- shaped exposure chamber, laterally inverted images which on development as positives are properly related for stereoscopic viewing. The plates P are pivoted between supporting plates D secured to the camera back C and are engaged by rollers K each carried between pairs of plates S pivoted at Q on the plates D. The plates S also support film guiding rollers R and pins W which are connected by a spring 1 so as to tension the film and press the plates P against it when the back is secured to the camera body. The perforated film Z is fed from a cassette H around the U-shaped chamber, the apertures in which are separated by a distance equal to that of two picture frames, over a measuring sprocket Y, which revolves once for each feed of two frames, to a clockwise rotatable take-up spool H<SP>1</SP>. Fixed to the spool shaft 12 are a gear 14 which through a gear 18 (shown in Figure 4 exploded into two parts) drives a gear 19, and a ratchet wheel 13 engageable by a tooth 15 of an anticlockwise urged lever 16 which in the rest position is held out of contact with the wheel 13 by a lug 42 on an anticlockwise urged member M. Secured to the gear 19 is a ratchet wheel 20 engaged by an anticlockwise urged pawl 22 (Fig. 5) on a gear wheel 21 meshing with a rack 26 on a slide 24 which engages with a shutter setting lever 38. Prior to winding on the film a lever 3 pivoted at ,4 must be moved clockwise by means of a button B when it is engaged by an anticlockwise urged latch arm 10, the clockwise movement of this arm causing a block J on the lever 3 to part the pins W and so release the presser plates P and the film tensioning rollers R. On rotating the take-up spool H<SP>1</SP> the film is wound across from the cassette H and simultaneously the shutter is set by the rack 26 and is held in the set position by an anticlockwise urged lever 43. When the right hand wedge end of the rack strikes a second lug 41 on the member M the lug 42 thereon moves downwardly to free the lever 16 which rotates anticlockwise so that a tooth 17 thereon engages an anticlockwise urged pawl 9. Continued movement of the rack causes a pin 25 thereon to strike the end 24 of the pawl 22 and rotate it clockwise to clear the ratchet wheel 20, in which position the pawl is held by a spring latch 23 engaging in a notch 221 in the pawl. The wheel 21 is thus disconnected from the film feed and is returned to its rest position by the rack 26 under its return spring 27. The film feed continues until a pin 7 on a disc 6 secured to the shaft 5 of the sprocket Y engages a tail on the pawl 9 as shown, releasing the lever 16 which then turns to latch the take-up spool shaft 12. Simultaneously with this latching a pin 8 on a disc 6<SP>1</SP> on the shaft 5 engages an arm 11 secured to the arm 10 latching the lever 3 so that the spring 1 may again clamp and tension the film by means of plates P and rollers R. To make an exposure, a stirrup-like member 34 is depressed whereupon a pin 36 thereon rotates clockwise the lever 37 to release the shutter setting lever 38 and a wedge 35 engages the lever 16 to move it clockwise beyond the lug 42, thereby freeing the shaft 12. Simultaneously a wedge 33 extending obliquely from the member 34 rotates clockwise an anticlockwise-urged pivoted lever 29 so that a pin 31 thereon engages the end 32 of the pawl 22 to free it from the spring latch 23 so that the wheel 21 is again coupled to the wheel 19 for further film-winding and shutter-setting. A clockwise-urged pawl 44 together with the finger 28 of the lever 29 engaging with the gear 19 ensures that the coupled ratchet wheel 20 always presents a space between the teeth to the pawl 22. By providing on the discs 6, 6<SP>1</SP> shorter pins 71, 81 diametrically opposite pins 7, 8 respectively, a film feed of only one frame at a time may be obtained by moving the journal for the two discs axially by any suitable means (not described). In this case the film is fed alternately one and three frame lengths.