Abstract: Apparatus for transporting a perforated web of photographic material in stepwise fashion has a variable-speed motor which drives the web, a bundle of light conductors which receive light seriatim when a perforation of the web passes between their ends and a light source whereby the conductors transmit light to associated phototransistors which effect the transmission of different first signals at timely spaced intervals to a comparator amplifier which further receives a continuous signal from a tachometer generator driven by the motor. The amplifier gradually decreases the speed of the motor to zero speed which is reached when the last phototransistor receives light from the respective conductor. The phototransistors are connected with an input of the amplifier by Darlington transistors, flip-flops, additional transistors and a chain of resistors.

Abstract: A feeding mechanism for supplying elongated strips of material, such as photographic print paper and the like, in a tension-free state by use of a slack loop of said material, the size of which varies in response to the demands of a processing machine. Said loop actuates a switch for energizing and deenergizing a drive mechanism for supplying said loop from a supply roll so that the size of the slack loop directly controls the supply mechanism.

Abstract: A drive shaft of an automatic printer engages tractors which, in turn, pull a paper web across a print mechanism. Located on the drive shaft is a drive shaft position cam which is fixed to the shaft and rotates therewith. Additionally, located upon the drive shaft for limited rotational movement thereon is a second cam. The shape of the second cam is similar to the shape of the first cam and formed integral with the second cam is a frictional surface engaged by the paper. During normal paper drive, the cams are out of registration and rotate in unison. In response to a paper jam condition, the first cam driven by the paper locks and the cams are forced into registration actuating a switch, the plunger of which rides on both of the cams. The switch signal thus serves to interrupt the paper drive mechanism in response to a paper jam condition.

Abstract: A web handling mechanism is described for incrementally feeding a web of stretchable material (e.g., plastic film) to a processing station. The web feed rollers are driven by a motor incorporated in a servo system which electronically controls the feed rate, length of increment, dwell at processing station, etc. Variations in the speed and elasticity of a moving web are accommodated by means of a vacuum box adapted to accumulate a loop of the web material in the box and maintain proper tension on the web as supplied to the feed rollers. A detector in the vacuum box responds to a predetermined length of web accumulated in the box to trip a control circuit which actuates the feed roller motor to move the desired length of web through the processing station and then stop for a preselected interval. The circuit also controls the processing station to synchronize its operation with that of the web feed and the entire sequence is repetitive at high speed.

Abstract: A control system for one or more vacuum holddown devices for use in an apparatus employing flexible web material in a flattened condition. A plurality of perforated plenums are joined to a manifold connectible to a vacuum producing means. The pressure within the manifold is sensed and must be at a predetermined pressure before the drive system for the web material is activated thereby preventing bulging or buckling of the web material during startup and normal running of the material.

Abstract: An automatic apparatus for feeding packaging strap, including a strap feeding mechanism having a pair of reversibly rotatable feed rolls for feeding and returning the strap and a detector for detecting the amount of strap fed and returned. Strap is fed to the feeding mechanism by a prefeeding mechanism having unidirectionally rotatable prefeed rolls and a detector for detecting the amount of strap prefed. A control mechanism determines the difference between the amount of strap fed and returned by the feeding mechanism and controls the prefeeding mechanism to prefeed an amount of strap equal to the difference.

Abstract: Continuous, uninterrupted paying of paper tape into a cable-making machine is made possible at high speed by an accumulating chamber for a folded supply of the tape. A pair of pinch rolls, one of which oscillates around the other, directs the paper to form uniform folds.