Patent GB-108914-A (GB)
Title: Improvements in and relating to Optical Projecting Apparatus.
Inventor: MATHYS ALBERT WILLIAM
IPC: G03B21/14
Filed: 1916-09-07
Abstract: 108,914. Mathys, A. W., (Dietz, P.). Sept. 7, 1916. Optical-projection apparatus.-The casing 10 of apparatus for projecting a series of non-kinematographic pictures from a film contains the film spools 22, 26 and film-moving mechanism, and is rotatable about the tube 5 containing the projecting-lens, the tube 5 being supported by a pillar 2 and projecting into the casing 10; the apparatus is thus capable of adjustment for projecting pictures arranged transversely or longitudinally on the film, and may also comprise (1) an indicator operated by the film to show the position of the apparatus necessary for the correct projection of the next picture on the film, (2) combined filmmoving and shutter mechanisms operated by means of a push-button which automatically returns to its normal position after the projection of a picture, and (3) a safety shutter normally kept open by the condenser or lamp tube, and closing when this tube is moved so as to prevent the possibility of igniting the film. The casing 10 is provided with a tube 9 which turns on the tube 5, its rotation being limited to 90 degrees by stops 11, and the front of the casing is dished to accommodate rings 12, 13 formed on the tube 5. A pivoted catch 19, operated by an arm 18 and held by a spring 20, snaps into one of the recesses 16, 17 in a sector 15 secured to the ring 12, to hold the casing stationary during projection. The film is moved by mechanism shown in side and front elevation in Figs. 4 and 5 respectively. Fingers 47a engage marginal perforations in the film and are carried by a slide 47 moving vertically. A link 50 connects the slide 47 with a lever 51 secured to a shaft 29, the shaft 'being turned by means of a lever 30 operated through links bv depressing a bush-button 37, which is shown in the depressed position. The slack film is wound on to the spool 26 simultaneously with the movement of the slide, by means of the ratchet mechanism 27. The slide is retained in the lower position by means of a catch 40 on a lever 38 held by a spring 41, the catch engaging one end of the lever 30. A shutter plate 42 having an exposure opening 43 therein also moves vertically, but is retained in the upper position, so as to cut off the light until the film movement is completed, by the engagement of a bracket 46 secured to it by a pivoted catch 54, the catch being ultimately released by the engagement of the lever 51 with a pin on a lever 52 which is linked to the catch, and the shutter being pulled down bv springs 45. When the picture has been exhibited for the desired time, the lever 38 is operated to disengage the catch 40, and the lever 30 is pulled over by a spring so as to raise the slide 47, the shutter 42, and the push-button 37. When films having pictures arranged some transversely and some longitudinally are used, incisions are made in the edge of the film so that a pin 61 carried by a lever 58 and bearing on the edge of the film may be pushed into the incisions by a spring 63, a clapper 62 carried by the lever 58 then completing an electric circuit to operate an alarm and inform the operator of the necessity for turning the casing before the projection of the next picture. The condenser casing 67 supports a pin 66 carried by a safety shutter 65, so that when the lamp chamber and the condenser are moved, the shutter may fall, or be pulled down by a spring 68, and intercept the light before the focus of the beam reaches the film.