Patent GB-1165791-A (GB)
Title: Motion Picture Projector
IPC: G03B1/56
Filed: 1967-03-10
Abstract: 1,165,791. Sound film apparatus. PANOPIX RESEARCH Inc. 10 March, 1967 [8 April, 1966], No. 11449/67. Heading G5R. [Also in Division G2] In a cine projector of the type disclosed in Specification 1,048,211 using broad film with multiple picture rows with corresponding sound tracks in a separate group, magazine 10 rests on a vertically movable platform 12 and is held by magnets 40 and solenoid-operated latch 44, locating pins 34 engaging recesses 36, 38. Film from the supply reel 16 passes round roller 24 and enters a gate 26 pivoted to the magazine at 28 and spring-urged outwardly so that the film is engaged by rubber driving roller 32 and drawn from the magazine. Self-threading.-After passing through capstan drum 62 and sound head, curved projection gate plates 68, 70, and timing sprocket 76, the film end is directed by guide 84 and pivoting guide 100 to press against hub 86 of take-up reel 88. The film leader has a reinforcing tape with holes which are engaegd by spikes on the reel hub 86. The film is continuously driven by roller 32, capstan 62 and by the take-up reel. Reels 16 and 88 are driven through opposed separate one-way friction clutches so that either may act as take-up reel in following the picture row sequence. After the first row has been projected, an optical or magnetic signal on the film is detected by detector 60 which actuates the step and reverse mechanism. Reel 88 has friction braking to prevent overrun on the final re-wind. Capstan drum (62), Fig. 14 (not shown), has an upper rubber sleeved portion (140) to engage the film and a lower metal face portion (142) with a separating groove 144 opposite the sound tracks which contains a photo-electric detecting member (164) on a support fixed to a platform (154) vertically movable relative to platform (12). Member (164) receives light from source (156) and optical system (160). Platform 12 has depending legs (174, 175) engaging posts (168, 170) upstanding from base (172), Fig. 7 (not shown), and sliding in ball bearings (176). The platform is spring-urged upwardly and is indexed from one picture row to the next by solenoid (190) operating an escapement mechanism comprising a spring- loaded pawl and ratchet bar on leg (175). A second solenoid on leg (174) engages a locating armature (220) with a series of openings (216) in post (170) for each indexing position. Platform 154 bearing the sound head is given a smaller indexing displacement since the sound tracks are closer together than the picture rows. Platform 154 is therefore driven by engaging at a suitable position, a lever pivoted to platform 12 and to a fixed post, see Fig. 8 (not shown). Capstan drive.-The capstan has a flywheel (244), Fig. 5 (not shown), fixed on shaft (138) on which driven pulley (246) is freely journalled. Shock-absorbing connection between pulley and flywheel is made through spiders (256) in the flywheel and interconnected by springs (260). The slots are rubber lined and smooth reversal of the capstan is therefore possible. Motor and drive.-A change speed pulley system and reduction gearing is provided whereby the correct framing speed may be selected for films with different picture dimensions. Optical system.-A folded optical path is used, with source 72 and rotating compensating prism 74, to give a projected image, on the integral screen of the projector cabinet by way of mirrors such as 332. External projection is possible with mirror 332 removed.