Patent GB-517497-A (GB)
Title: Improvements in or relating to an optical projection apparatus
IPC: G03B1/56
Filed: 1938-10-07
Abstract: 517,497. Optical-projection apparatus. KODAK, Ltd. Oct. 7, 1938, No. 29093. Convention date, Oct. 7, 1937.. [Class 97 (i)] In optical-projection apparatus wherein a film strip is fed by rotation of a reel spindle, the gate is opened, prior to the rotation of the reel spindle, by means controlled by the reel-rotating means, and is maintained open during the feeding of any desired film length; the means may be capable of rotating either reel spindle, and means may be provided for adjusting the position of the film, reels, gate &c. so that, when part only of printed matter &c. on the film is to be projected; the part projected may be varied. Figs. 3 and 4 show a gate comprising glass plates 17 held in frames 16 respectively carried by a fixed plate 12 and a slidable plate 13, the plates being drawn together by a spring 14. Pins 20 depend from the plate 13, and are alternatively engageable by a member 60, rockable about a shaft 23, to slide the plate and open the gate to the limit determined by a stop 45. The member 60 is loosely mounted on the shaft 23 between collars 61, 62 secured to the shaft, and is frictionally engaged by a spring washer 65. A gear 70 secured to the collar 62 engages gears 71 mounted on the member 60, and the gears 71 may alternatively be engaged with gears 75 respectively carried by two reel spindles 53. When feeding is to be effected, the shaft 23 is driven by hand, through gearing, in one direction or the other, and rocks the member 60 to open the gate. The rocking subsequently causes one pair of gears 71, 75 to engage, to drive one of the film reels. A spring 80 restores the member 60 to its normal position, when the drive is discontinued. In a modification, the gears 71, 75 are omitted, and the reels are alternatively driven by pulleys and belts, two driving pulleys being provided on the shaft 23 and connected therewith by pawls and oppositely cut ratchets. Fig. 5 shows a construction wherein a helical gear 116 on a driven shaft engages a helical gear 115 loose on a shaft 108. The gear 115 carries two clutch elements 132 alternatively engageable, as the gear slides axially owing to the drive, with clutch elements 133 on belt pulleys 109 connected to pulleys on the reel spindles 53. The gear 115 is also provided with a grooved collar 126 engaged by pins on one arm of each of two pivoted T-shaped members 120; rocking of the members 120 about their pivots 121, effected by axial movement of the gear 115, slides a member 100 against the action of a spring 14 to move a gate member 91 away from fixed gate member 90, this move-' ment being effected before engagement of the clutch elements. The reels 110 and the gate members &c. are carried by a plate 94 which is movable transversely to the direction of feed to position the film with respect to the projection beam through the lens 150; the movement may be effected by cams 151 rotatable about a shaft 152, and within slots in fixed rods 146, to raise sleeves 145 which surround the rods 146 and are secured to the plate 94. U.S.A. Specification 2,008,982 is referred to.