Abstract: A multi-position proximity switch having a plurality of binary outputs, each output indicating whether the distance between an object and a field transducer exceeds a corresponding one of a plurality of predefined distances. The sensitivity of a proximity detector having a single binary output is stepped through a plurality of adjustable levels by a digital counter having decoded outputs and the binary output of the proximity switch is sampled after the decoded counter outputs change state so that a plurality of binary outputs, each associated with a detector sensitivity level and a corresponding distance, are provided. The failure of the greatest distance to be detected or the detection of the smallest distance activates an alarm indicating that the object is outside a permissible range of distances.

Abstract: A system for detecting missing or superimposed sheets fed to a sheet processing machine uses a measuring device for generating a signal increasing with the number of superimposed sheets and an evaluating device for emitting an electrical signal when irregularities occur. A pulse transmitter is synchronized to the sheet feed mechanism and operates to emit an initial and final pulse timed to the sheet feed. Electronic storage is reset upon the initial pulse, and operates to integrate values of the measured signal until the final pulse is received. Upon receipt of the final pulse, the stored value is compared to a reference value to detect any irregularities. Preferably a microcomputer is used for signal processing.

Abstract: A method of and apparatus for automatically loading a circular sheet pile feeder with successive splayed piles of sheets removed from a stack of sheets disposed on a pallet are disclosed. A pile of sheets of a given height is separated from the stack on the pallet by means of a separating mechanism which forms a gap beneath the pile of sheets in which gap a roller conveyor table is inserted to pick up the pile. The pile is then conveyed upwardly and transversely to a second conveyor table where the pile is deposited and the sheets thereof are tamped into alignment. The second conveyor table transports the pile of sheets to a splaying mechanism where the pile is splayed by gripping one end of the pile, bending the same about an axis parallel to said end and returning the bent end to its normal, unbent position while clamping the pile intermediate its ends.

Abstract: The invention relates to a control arrangement for sheet feeders having a pull-off device for transferring the sheets serially to a continuously operating conveyor apparatus, with disposed in the path of the sheets, a sensor which, when it recognises the rear edge of a sheet, generates a switching signal by means of which the pull-off device can be switched on, and having a switch arrangement by means of which the pull-off device can be switched off after a delay.