1,217,157. Folding paper &c. THOMAS BROADBENT & SONS Ltd. 28 May, 1968 [17 June, 1967], No. 28023/67. Heading B8R. [Also in Division D1] A machine for folding a flat workpiece 16 is provided with a control apparatus comprising a first detector and transmitter unit 14 arranged to detect and measure a dimension of a travelling workpiece 16 and transmit a signal whose value is representative of the dimension to a first memory store C1, means for transferring at least part of the signal in the first memory store C1 to a second memory store C2, and a second transmitter 24 to transmit to the store C2 a further and cumulative signal representative of the passage of the workpiece 16 relative to a folding station 32, the store C2 being arranged to initiate a folding operation when the required length of workpiece has passed the folding station. As shown, the workpiece 16 travels along the upper run of conveyer belts 10 arranged above conveyer belts 12 and actuates the first transmitter 13 comprising a rotatable toothed wheel the teeth of which are arranged to alternately interrupt and restore a light beam impinging on a photo-cell. The output of the transmitter, comprising a sawtooth voltage, is fed to a pulse shaping circuit 11, Fig. 2 (not shown), which comprises a Schmitt trigger semi-conductor circuit followed by a mono-stable multivibrator equipped with a resistance-capacitance delay circuit arranged to set a constant pulse width. The train of pulses produced by the circuit 11 is fed to a resistance-capacitance circuit R1- C1, Fig. 3, of an R-C circuit for the length of time that the detector, e.g. a feeler switch, associated with the unit 14 is actuated to open a contact 18 to charge the capacitor C1 When the workpiece 16 has completely passed the unit 14 the detector opens a contact 20, and simultaneously closes a contact 22 momentarily so that a capacitor C2, connected in parallel to the capacitor C1, acquires a part of the charge of the capacitor C1. The contact 18 closes and discharges the capacitor C1. The transmitter 24 is connected to a pulley 28 over which the belts 10 pass by a shaft 26 which thus rotates at a speed proportional to that of the workpiece. After the workpiece 16 has passed beyond the unit 14, the output voltage of the transmitter 24 is fed cumulatively to the capacitor C2 through a resistance R2 via a pulse shaping circuit 30 similar to the circuit 11. When the capacitor C2 has been charged to a predetermined voltage an output circuit, Fig. 4 (not shown), conducts to operate a folding blade 32. Simultaneously, the contact 20, Fig. 3, closes to completely discharge the capacitor C2 to prepare it for the next folding cycle. In another embodiment (not shown), a third memory store is provided together with means for dividing and transferring thereto any remaining signal stored in the first memory store after the original information has been transferred to the second memory store, whereby a further folding operation can be initiated by the third store. In a further embodiment (not shown), a third memory store may be provided together with means for dividing the original information transferred from the first memory store between the second and third memory stores whereby further folding operations can be initiated by the third memory store.