Method of and apparatus for automatically discarding the front and rear ends of bars of material

A method of automatically discarding the front and rear ends of bars of material of finite length initially continuously moving, the bars of material along a straight-line conveyor track and then feeding, by intermittent forward pushing against an end-stop, to a shearing blade, in whose vicinity at least the front end and the rear end of each bar of material is discarded, connecting at least one sensing device provided in the region of the conveyor track of the bars of material to a counter and delivering a control pulse to the counter whenever the interface between two successive bars of material passes, wherein the distance (a) between two sensing devices located in the region of the conveyor track, and at least the distances (b, d) of one sensing device from a pair of feed rollers and from the shearing plane or the plane of the end-stop, are stored in a microprocessor and recording the time interval during which an end of a bar traverses the track distance (a) between the two sensing devices, re-expressing the remaining distances (b, d) in terms of time intervals, and discarding one or, at the most, two section lengths for each interface between successive bars, depending on whether the interface between bars is located in the central region of the section length in question, or in one of the two end regions, discarding being effected in the vicinity of the shearing device, by reference to the control data stored and computed in the microprocessor.