Abstract: A folding machine has workpiece sensing means including an emitter by which an "outside" corner in the workpiece edge approaching the operating locality of the machine can be sensed, such sensing causing the feed length by which the workpiece is advanced step-by-step through the operating locality to be reduced; this conventionally causes pleating in the folded over edge portion. In addition, delay means is provided by which, after the emitter has been re-covered by the workpiece, the feed length reduction continues for a given number of further feed steps.

Abstract: In a thermo-cementing and folding machine which has a suck-back facility, by which at the end of an adhesive-applying operation adhesive supplied through the nozzle (22) is sucked back into the nozzle so as to prevent `drooling`, auxiliary suck-back steps are introduced at timed intervals following the primary suck-back operation, through controlled amounts, in order to counter further risk of `drooling` caused by thermal expansion of the adhesive in the nozzle (22). The number of auxiliary suck-back steps is variable according to the adhesive supply rate at the time of termination of the adhesive-applying operation.