Patent GB-973442-A (GB)
Title: Motion picture projector
IPC: G03B21/32
Filed: 1962-03-30
Abstract: 973,442. Cinematographic projection apparatus. TECHNICOLOR CORPORATION OF AMERICA. March 30, 1962 [April 3, 1961], No. 12260/62. Heading G2E. A projector is adapted for use with interchangeable cartridges 17 (Fig. 12), each containing an endless roll of film, in each of which cartridges the loop of film 45 connecting the inner and outer convolutions of the roll is guided past a projection aperture 63 and each of which cartridges includes a cavity 73 for facilitating illumination of said aperture. As shown (Fig. 2), the projector comprises a socket 16 for removably receiving such a cartridge 17, a lamp 19, a mirror (95-Fig. 7) retractably mounted by toggle members 80 and 81 for projection into the cavity 73 for directing light from the lamp 19 on to the projection aperture 63, intermittent feed means 121 (Fig. 3), a shutter disc 117 with three apertures 120 and a projection lens 140. The socket 16 includes projections 69. (Fig. 16) which engage in apertures 68 in the sprung aperture plate 59 of the cartridge 17 for accurately locating the film 45 therebetween in the region of the projection aperture. The mounting of the mirror 95, shown in Fig. 7, comprises a toggle member 80 pivoted at 83 and carrying a pin 92, a second toggle member 81 pivoted at 91 and engaging the pin 92 by a slot 94 and a further member 82 integral with the mirror which is pivotally mounted on the pin 92 and engages the shaft 91 with a slot 96. The shaft 83 on which the member 80 is mounted is under the action of an overcentre spring 111 so that the mirror may only adopt either a retracted position or the position shown in which it projects into the cavity 73 of a cartridge 17. The shaft 83 is provided with a knob 114 (Fig. 3) for movement of the mirror into its two positions. Abutment surfaces 100, 102 are provided on the members 80, 81 respectively whereby the mirror is automatically retracted (if not already in this position) during removal or insertion of a cartridge 17. A cam member 110 on the shaft 83 operates a switch 112 to de-energize the lamp 19 and projector motor 20 whenever the mirror is retracted and vice versa. A spring 103, engaging in the cavity 73, resiliently holds the cartridge in place in the socket 16. An apertured shield 98 integral with the mirror limits illumination to the gate area alone. The shutter disc 117 is driven by the motor 20 by way of belt and pulley transmission 116, 119 and a speed reducer 21. The motor also drives a fan 146 for drawing cooling air through the projector and out through a grill 147. The intermittent feed mechanism includes a claw 121 (Figs. 3, 7 and 16) which automatically engages with the perforations in the film on insertion of a cartridge, slots being provided therefor in the projecting part 69 of the socket 16 and also in the aperture plate 59. The claw, mounted on an arm pivoted at 123, is moved in the feed direction by a cam 126 and in and out of the film perforations by a cam 128, both cams rotating with the shutter disc and a spring 130 being provided to urge the claw arm against the cam 128. Framing adjustment is effected by movement of the pivot 123, this being provided on a member 124 pivoted at 125 and spring-urged against a threaded screw 132 mounted in a threaded boss 133 and rotatable by a knob 137. A spool for the electric supply cable is provided at 23. The construction of the cartridge is shown in Figs. 6 and 7. Two parts 30, 31 are secured together by a screw 33 and enclose the main roll 41 of the film in a cylindrical chamber 40 on a rotatable flangeless spool 36. This spool comprises a ridge portion 55 for engaging the film in the region of the perforations, a cylindrical part 57 and a frustoconical interconnecting part 58 down which the innermost convolution of film roll slips when it is led out for projection. A springy finger 48 cushions the film against the intermittent feeding motion at the projection gate. Means provided for protecting the film against damage include the mounting of the film on the spool by its edge portion only (by the ridge 55) the springy finger 48, guiding of the film through the projection gate by its edge portions only (see for example guide ridges 66 on the aperture plate 59 in Fig. 16) and a spacer member 52 which prevents fouling of the edge of the returning film with the outer edge of the roll of film 41. The cartridge (apart from the aperture plate 59 which is metal) is constructed of a material having dielectric properties so as to attract dust and dirt by static electricity away from the film. Ridges 71 and 72 are provided to facilitate gripping of the cartridges. Specification 973,443 is referred to.