Patent GB-190411821-A (GB)
Title: Improvements in and connected with Cinematographs and like Apparatus.
Inventor: MASON JOSEPH
Filed: 1904-05-24
Granted: 1905-04-06
Abstract: 11,821. Mason, J. May 24. Kinematographs.-Relates to apparatus in which a continuous film, bearing pictures or photographs of successive phases of objects in motion, is made to pass through the field of a projecting - system, means being provided to prevent firing of the film or to check the spread of fire, to enable the pictures to be centered during an operation, and to prevent flickering. Figs. 1 and 2 show an arrangement in which the film a passes from the delivery roll b over tension rollers to a sprocket-wheel c driven through differential gear to enable it to be retarded or accelerated so as to centre the pictures. Fig. 4 shows the sprocketwheel c mounted loosely on the shaft e. Two spur-wheels g,j, of unequal values, are fixed to the wheel c and the shaft e respectively, and gear with a pinion j carried by a milled cap h mounted loosely on the shaft e. These parts are held normally in frictional engagement, so as to rotate together, by a stiff spring n and a disc m secured to the shaft e. The pictures are centered by retarding or accelerating the cap h. The film is led from the sprocketwheel c between a clamping-frame containing the mat, which is in the form of a loose plate o, Fig. 2, with an opening. When the film is stationary, it is pressed against a hinged frame p, Fig. 1, to prevent the spread of fire in case the exposed area of the film is ignited, by a pivoted framework q pressed against the mat by a spring r acting through a bellcrank lever s and a bar t. The lever s is operated by the driving-mechanism, to relieve the pressure of the spring periodically. A tappet lever u. connected by a rod v to a crank disc w, may be used for this purpose. A contact-screw may be provided at the end of the tappet lever, to adjust the release. The film passes from the mat between two gripping-drums x, 2, the large drum x being fitted on a small portion of its circumference only, and the small drum 2 on the whole of its circumference, with felt or like gripping-material, so as to cause the film to be fed intermittently, the period of motion being small compared with the period of rest, so as to avoid flickering. The small segment of felt 3 is preferably carried by a small detachable block 4 whichcan be reversed when worn on one side. The pressure between the gripping-surfaces may be finely adjusted by a screw 11, which adjusts a spring-operated lever 9, pivoted at 10 and carrying the shaft of the drum 2. An improved effect maybe obtained by revolving a four-armed shutter 6 in front of the projecting- lens. Tubes of fireproof material 12, Fig. 7, are disposed preferably on both sides of the mat, to prevent any film which way accidently unroll from falling across the projected rays and being ignited, As a further precaution against fire, the film may pass through shoots above and below the optical axis. Parts ot these shoots may be hinged to facilitate the insertion of the film. Fig. 7 shows clamping-devices 14, 15 for preventing the spread of fire. The moving members 14 are carried by spring-operated levers normally held out of action by an inflammable ligament 19. The part of this ligament crossing the projected rays may be fireproof. The clamping-devices may be replaced by shearing-devices, and shields or guards may be provided on them as a further safeguard against fire.