GB581095A - Indicating device for metal stretching machines - Google Patents

Abstract

581,095. Stretching. LOEWY ENGINEERING CO., Ltd., and SALTER, F. S. Aug. 8, 1944, No. 15020. [Class 83 (iv)] In a machine for stretching metal bars, sheets, &c. in'order to straighten them, means are provided for indicating the initial length of the bar &c. and for indicating the total elongation during stretching so that a total stretch may be performed to produce a given percentage elongation. The bar M is gripped by an adjustable fixed head 12 and a movable head 11, the head 12 being mounted on a carriage 16 adjustable along the machine bed by a motor 19, worm gearing 20 and chain and sprockets 23, 24, and being locked in working position by hooks 17 engaging notches 18 on the bed. The head 11 is moved during stretching by a hydraulic ram 14 supplied from a pump 69 under control of a manuallyoperated valve 70 and the operating pressure is indicated by a gauge 63 and adjusted by a relief valve 67 which is set to the required pressure by a knob 66 and graduated dial 65. Adjustment of the head 12 is indicated directly on a linear scale 26 and a sprocket 27 on the adjusting shaft 21 is connected to a shaft 30 carrying an indicating dial 31. An outer scale A, Fig. 4, on dial 31 is graduated in total lengths of the bar M from 100 to 600 inches and a series of inner scales B give the inches of stretching required to produce an elongation of from 1 per cent to 5 per cent. The figures on scales B correspond to a figure on scale A which is diametrically opposite on the dial. The head 11 carries an arm 41 connected by a chain 42 to a sleeve 44 rotatable on shaft 30 and formed integral with part 45 of a friction clutch, the other part 46 being attached to an indicating dial 48 graduated in inches of stretch of the bar M. A dog 59 on the dial 48 engages a graduated Geneva wheel 60 once per revolution to indicate multiples of ten inches of stretch. A mask 84, Fig. 3, overlying the scales B has a series of windows 75 and is rotatable by a knob 86 so as to bring one of the windows over the scale B which indicates the required percentage elongation. In operation, to produce a 4 per cent elongation in a bar 280 inches long, movement of head 12 to the position which accommodates this bar will bring the 280 graduation of scale 31 opposite a fixed window 83, as shown in Fig. 3. Adjustment of mask 84 to bring the 4 per cent window 75 within a fixed window 82 will show 11.2 inches. as the required total stretch, and the valve 70 may then be actuated to move the head 11. When the pressure in the supply line 62 has reached the value necessary to start stretching of rod M, fluid in a branch 621 will actuate a piston 53 to rock a lever 50 and engage clutch 45, 46, whereupon dials 48, 60 will be rotated to indicate the inches of stretch imparted by head 11 to the bar M. When this value, seen in a fixed window 81, Fig. 3, reaches the value shown in window 82, the stretching operation is stopped. On release of pressure in the line 62, the clutch 45, 46 is disengaged by a helical spring and the dial 48 is returned to zero position by a volute spring.