GB1416183A - Flying cut-offs for machines for handling elongated products - Google Patents

Abstract

1416183 Flying cut-off apparatus TUBE PRODUCTS Ltd 23 Feb 1973 [29 Feb 1972] 9253/72 Heading B5L [Also in Divisions B3 and G3] A carriage 3 carrying a shear or saw 2 is accelerated to the speed of stock 1, at which point clamps 5 engage the stock by a ram 6 which is restrained by a latch 7, until a predetermined length of such has been fed, while pneumatic pressure is built up in the ram, the pessure being controlled by a regulator 8 itself controlled continuously and automatically in accordance with the speed of the stock. A wheel 10 driven by the moving stock drives a tachometer generator 11 and the pulses produced are shaped at 12 and converted at 13 to a voltage signal which is smoother and amplified at 14 and shaped at 15. The circuit 15 accommodates the non-linear relation between the speed of the stock and the boost pressure required in the ram to accelerate the carriage to that speed. A signal, having passed through a wavelength circuit 16 is compared at 17 with the actual pressure in the ram cylinder and the resulting signal if positive or negative drives a reversible motor 20 acting on the regulator 8 direct or, preferably, on a servo-regulator 21. If the flying cut-off follows a tube-making mill, when the mill is re-started after a switchoff the stock would normally reach its desired speed more quickly than the servo motor 20 could boost the ram pressure. To avoid this, back contacts are provided on the main switch in the mill which energize a relay which interrupts the drive to motor 20 when the mill is switched off, leaving the pressure setting fixed at the valve it held at the moment of switch-off. Alternatively, the tachometer generator wheel 11 is replaced by a potentiometer ganged to the spindle of the control for the speed of the mill and thus the stock. The degree of boost will then match the setting of the mill control knob even when the mill is switched off.