Patent GB-899932-A (GB)
IPC: G03B23/04
Abstract: 899,932. Projectors. KODAK Ltd. Nov. 13, 1958 [Nov. 14, 1957], No. 36530/58. Class 97(1). A slide projector adapted to receive a slide magazine-comprises a slide changing mechanism operable to automatically move the slides to the gate position and back to the magazine and to index the magazine, and power operated means and manually-operated means for operating said mechanisms a clutch disengageable by said second means being placed between the first means and the mechanism. The projector Figs. 2, 7 is adapted to receive magazines 60 the slide compartments of which are of different spacing length so that the rack 66 which indexes the magazine is shaped so as to engage either pinion 67 or 77 on a shaft 69. The slides are as described in Specification 864,302. The projector includes an elevator which lowers a slide in its holder into the magazine from the gate and lifts another one up to said gate. Brackets 85 on a lifting member 84 engage ears 56 of the slide holder 46 and by oscillating a lever, the slide holder is lifted up to the gate and down again being guided vertically by the backing plate 36 of the gate which engages shoes 88, 90 on the elevator. The slides can be withdrawn at the gate position by means of a device operated by levers 100, 110 in which an ear 118 on lever 110 engages an ear on the slide holder and lifts it up to a hole in the top of the projector. The elevator, shutter and cyclic magazine indexing mechanism are driven through a hand crank-shaft 120 which may be driven by a hand crank 122 or a motor. The shaft is connected via gears to a programming wheel 142 Fig. 11 secured to a shaft 140. The wheel 142 is attached indirectly to the elevator lever 96 and also operates a shutter 158 via a shutter bracket 156 pivoted at 160 so that no movement of the slides is projected. The hand crank-shaft is connected by a system of gears to the shaft 69 so that the slide magazine only moves when the elevator is fully down. The slide can be projected and indexed manually by pushing a knob 190 Fig. 20 on shaft 192 Fig. 11 towards the centre of the projector to disengage an automatic indexing clutch 180, and rotating said knob to move the magazine in either direction. In order to prevent the magazine from being indexed when the elevator is not fully down the knob 190 is interlocked with the hand crank 122 as shown in Fig. 20. in the event of a slide getting jammed the indexing clutch 180 can be disengaged by means of a lever 200 which can move gear 172 to the right (Fig. 14) by means of an ear 214. For push button or automatic slide changing the shaft 120 is driven by a motor 220 (Fig. 15) through a spring clutch, the clutch shaft 124 and a hand crank clutch. The spring clutch comprises two sleeves 254, 256 which are journalled by a coil spring 258 one end of which is secured to sleeve 256, the other end is 260. When end 260 is held stationary the coils of spring 258 become loose and sleeve 254 which is driven by the motor no longer drives shaft 124 which drives the elevator, shutter and indexing mechanism. The position of the end 260 of the spring is controlled by an armature plate of an electromagnet and the current in its coils which is controlled by a push button switch. The armature plate can also be controlled automatically by setting a timing wheel 288 Fig. 15 which has lobes 292, 294, 296 of different sizes corresponding to different frequencies of the slide changing cycle so that predetermined lobes engage an arm on the armature plate 262 Fig. 11. The lever 100, Fig. 7, is locked during automatic slide changing by means of a flange 316 movably connected to the timing wheel (Fig. 15). Also, during any power operation the hand crank clutch is disengaged. An ear 354 on a pawl only engages step 362 on a snail cam 360 during power operation (Fig. 20). The electrical circuit is described and also a method of preheating the slides. Specification 899,933 also is referred to.