| 摘要 |
<p>1,261,574. Shearing. MOELLER & NEUMANN G.m.b.H. 20 March, 1969 [20 March, 1968], No. 14650/69. Heading B3W. A shearing line comprises opposed edge trimming shears D1, D2 followed so closely by cross cut-shears T, which comprise a curved blade making a rolling cut, that the sheets are cut while still gripped by intermittently operating feed rollers 4, 6, 8 which clamp the sheets during the cross cut, which derive their stepwise drive from the continuous drive of the edge trimming shears and the feed step of which preceding a cross cut can be shortened independently of that drive e.g. for making a front crop cut and for varying the last or last two feed steps of a sheet to make the rear crop length sufficient for the cross cut blades to operate effectively. The rollers are normally driven by a cam wheel 40 mounted on the crank-shaft of the edge trimming shears closing a switch 41 controlling the motors V m driving the rollers. The switch opens automatically under spring pressure. The operation of the rollers can be overridden for the front crop cut by means of a push-button 48 which isolates the motors V m regardless of the cam position and actuates the motors T m of the cross out shear. The second cut is made when a predetermined length of sheet has passed through the cross cut shear, by means of a lengthmeasuring roller 10 connected to the control circuit by means of a pick up 58 and a comparator 60. A preliminary switching device 80 ensures that the pick-up transmits signals immediately the front crop cut is made. A signal from the comparators shortly before the nominal/actual value comparison is zero slows down the motor V m gradually. A similar comparison is used to reduce the final feed step when the desired sheet length is not an aliquot multiple of the feed step, i.e. the distance corresponding to one revolution of cam wheel 40. If the desired sheet length is only slightly more than an aliquot multiple of the feed step the last two feed steps are reduced. A transverse scrap cutting blade (not shown) is mounted at one end of each trimming blade. The rolling cut of the cross cut shears T is produced by out-ofphase cranks (26), (28), Fig. 3 (not shown). The sheets are supported by rollways which, at least within the cross cut shears T, have free-running rollers and are aligned for the shear T by edge guide rollers 16. A conventional ejector 12 is provided.</p> |
