Richardson's handbook of projection (1930)

1186 HANDBOOK OF PROJECTION FOR The device is driven by either a D C motor, with its detector which energizes a specially wound D. C. magnet coil, or by an A C motor, with its detector which energizes a special A. C. magnet coil, according to the kind of supply current available to the theatre. The take-up is of the friction disc type. It is adjustable. Fig. 431 shows the machine as a whole, with the lower magazine door open. The magazines are 17 inches in diameter. 2 is the detector box, shown in detail in Figs. 2 and 3. Part 8 houses the mechanism shown in Fig. 432. 7 is the handle or lever by means of which the mechanism is put into operation. The film passes through slot 5 and thence into the lower magazine. The table, 6, Fig. 431, is of ample size for making film repairs. I would respectfully suggest to the manufacturers that a good splice-making device attached to the table would be a desirable addition. In Fig. 432 we have a side view of the fault detecting mechanism contained in casing 2, Fig. 431. The detector casing is held to the machine frame by two bolts, the upper one of which is indicated by 11. 12, Fig. 432, is one of the four nuts by means of which the tension (supplied by a coil spring) of the detector is adjusted, the coil spring itself is numbered 13. At 14 are tungsten contact points which close whenever either of the four detector fingers pass over a defective portion of the film, or, if set that way, over a splice. The closing of these points automatically stops the mechanism. 18 are the binding posts to which the electric circuit attaches. Fig. 433 is a view of the film track and gate of the detector box, the gate being in open position. Above is the lower edge of the upper magazine and at the left the supporting column. The detector box really is attached