Principles of cinematography : a handbook of motion picture technology (1953)

PROCESSING EQUIPMENT 81 is carried out. The film ends are then raised and two metal rivets are inserted in the cupped heads of the dies so that the larger diameter of each rivet is at the bottom. A heavily built punch, mounted above these dies, carries two pins designed to perforate the film, force it over the rivet heads and then firmly to close these heads, so locking the two films together. This action is all carried out in the one operation of closing the punch smartly over the film path. Before releasing the film sprocket (8), Figure 33, the clamps holding the film in the splicer should be released, the film taken out, and the edges of the joint trimmed with scissors as close to the rivet heads as possible. A small latch, located above the pawl which locks the sprocket wheel (8), is then raised to allow this sprocket to rotate once more. The latch projects through an opening in the back of the solenoid housing. Fig. 34. — Splicing unit for film processing. The Film Feed Elevator The foregoing operations will, after a little practice, be accomplished within about 45 seconds but, during this time, the processing tanks must be continuously fed with film. Time in which to perform this operation is gained by causing the film to pass through a feed elevator, situated between the splicing table and the first processing bath and seen at (9) and (10), Figure 33. The top rollers of this unit (9) rotate about a fixed axle, but the lower rollers (10) are mounted in a frame which can move in a vertical direction along two highly polished runners. The frame carrying the lower rollers is weighted so that its normal position will be at the bottom of the guide channel. When the sprocket wheel (8) is locked in a stationary position, and the trailing end of a roll of film is held in readiness to be stapled to the leading edge of the next film, the processing tanks