Living pictures; their history, photoproduction and practical workingWith a digest of British patents and annotated bibliography . this has passed there will vO_be no grip on the film, which willremain stationary until the pro-jecting part of the left-hand rolleragain comes round. Naturallythis segmental piece exertingpressure on the film is so pro-portioned that its length is exactly equal to one Biograph works somewhat on this principle, but itsdetails are so complicated that the machine must bedescribed later on as a whole. Ci. Film moved by spring-teeth. In a degree the
Living pictures; their history, photoproduction and practical workingWith a digest of British patents and annotated bibliography . this has passed there will vO_be no grip on the film, which willremain stationary until the pro-jecting part of the left-hand rolleragain comes round. Naturallythis segmental piece exertingpressure on the film is so pro-portioned that its length is exactly equal to one Biograph works somewhat on this principle, but itsdetails are so complicated that the machine must bedescribed later on as a whole. Ci. Film moved by spring-teeth. In a degree the spring-fork used by Gray in 1895(Figs. 88 and 89) was the forerunner of the spring-tooth, and in the same moderatedegree a resemblance may betraced in the rising wheelgoverned by a ratchet whichwas shown in Fig. 129. Inthat arrangement the toothacting on the film was ableto travel over the film in onedirection, and was fixed whenmoving the other way by theaction of a ratchet-tooth, butthis ratchet-tooth did not actIn the spring-claw, properlyFig. 134 may serve to explainthe action, it being understood that this is a double-. FiG. 133. directly on the filmso-called, it does so. 124 LIVING PICTURES. ^. action device, one spring-tooth serving to move thefibxi and the other to steady it. H and d are twosimilar spring frames, but H is fixed while d slides upand down on a bearing, G. As shown, the tooth d^ has just brought the film downand is momentarily at rest inorder to steady the film, beingpressed home by the stop ^W^ ^ K^ Now, when the frame d begins ^ m^ W^ ^^ ^^^^ ^° soon as it is free from the pressure of g, the tooth d^will have no action on the film,but will drag over it as thespring part d yields a friction of the tooth is pre-vented from shifting the filmin the slightest degree by theaction of the fixed spring-toothattached to H. When D hasarrived at the top of itsstroke and begins its down-ward journey the tooth d^falls into a film perforation andcatch
Size: 1454px × 1719px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booki, booksubjectmotionpictures
