GB1274964A - Improvements in or relating to methods of straightening sheet metal - Google Patents

Abstract

1,274,964. Straightening; altering physical properties. I. UNGERER. 5 May, 1970 [17 May, 1969], No. 21586/70. Headings B3E and B3V. A method of straightening a metal sheet or strip is characterized in that a vibration is imparted to the sheet or strip during the straightening process. A straightening machine for carrying the method comprises an upper and lower assembly of rolls 2 and 3 respectively between which runs the metal strip 4. A vibrator 5 acts through linkage 6 and 7 on the rolls 2 (Fig. 1) which effect vertical oscillations perpendicularly to and transversely to the strip 4 which assist the straightening process and produce a stress-free flat strip. Two such machines can be arranged in series with the second set of rolls running faster and then slower than the first set of rolls so that the strip is subjected to a selectable variable tension during its passage through the two machines (Fig. 3, not shown). In another embodiment the vibrator is positioned between the sets of rollers and acts directly on the strip (Figs. 9 and 10, not shown). In a further embodiment retaining rolls 10, 11 and variably driven traction rolls 12, 13 (Fig. 2) are used and the vibrator comprises rolls 17, 18 mounted on two oscillating arms 15, 16. As the rolls are on opposite sides of the strip 4 oppositely directed pulsating alternating bending stresses are imparted to the strip. The retaining and traction rolls can each have their own vibrator mounted in their separate housings (Fig. 4) the vibrators oscillating the upper rolls at preselected frequencies and in the same or opposite directions to effect tensioning and alternate bending stresses in the strip. The machine of Fig. 4 can be housed in a single frame and additional idler rolls added to one of which is attached the vibrator (Figs. 5 and 6, not shown). Alternatively, the vibrator 53 (Fig. 7, not shown) and 59 (Fig. 8, not shown) is positioned between the roll housings. Another arrangement is given in Fig. 11 (not shown) and in another embodiment a series of vibrators 77, 78 and 79 with intermediate rolls 71 to 76 (Fig. 12) are used. The strip can be made to oscillate transversely by a vibrator placed directly before the straightening rolls, (Fig. 13, not shown) and no tension is imparted to the strip. In a further embodiment two vibrators 85, 86 act on the upper traction roll 12 (Fig. 14) to effect axial oscillations which due to the friction between the roll and the strip the bending stresses act diagonally on the strip and transversely to its feed. The vibration generators may be mechanical e.g. cams; electromagnetic; pneumatic; acoustic by sound or by inaudible ultrasonics.