| 摘要 |
1389184 Making corrugated ducts KARL MEINIG KG 17 Jan 1973 [26 Jan 1972] 2527/73 Headings B3A and B3E [Also in Division F2] A method of manufacturing sheet-metal ducts, Fig. 8, of rectangular cross-section comprises feeding strip 3b from a coil 3, Fig. 1, to a shaping unit B to produce a rolled flange section 3c, Fig. 3, on both edges of the strip; providing incisions in the flange at distances corresponding to the final dimensions of the duct, bending the strip in a folding unit C to form a rectangle (3e)- (3h), Fig. 7e (not shown), and cutting the formed duct from the strip. The uncoiled strip is straightened using rollers 6 and provided with triangular flange sections 3c by rollers 4. Additional rollers (5), Fig. 2 (not shown), impart a shallow zig-zag profile to the strip to produce reinforcing tines 21, 22 in the finished duct. The sections are spot welded at 7 and the strip fed by rollers 4, via driven guide rollers 8, to unit C where an overlap 3d, Fig. 3, is produced. The strip is clamped by upper jaw 10 and circular saws 12 make incisions in the sections 3c. The section 3c attached to overlap 3d is cut off using sheet-metal shears (not shown). The overlap is then folded and the sheet fed to a limit stop 14 adjusted according to the required dimensions of the finished duct. A switch 14a stops the feed and folding of the strip begins. Upper jaw 10 is again lowered, saws 12 raised into their cutting position and support arms 13 and bending jaw 11 swivelled about edge 9a. The upper jaw is disengaged and the feed restarted until a further folding step is required to form a duct of rectangular section, Fig. 7a-7e (not shown). Upon completion of four bending operations the cutting-off operation is automatically triggered by a control device. The duct is cut off the strip using a cutting roller 15a which is lowered into a gap between edges 9a, 11a and rotating saw blades 12a are raised to cut through the strip section. The overlap 3d may be secured to adjacent wall section (3h) by a rolled seam or a projection or spot welding machine. Corner angle pieces (16), (18), Figs. 9, 10 (not shown), 19, 20 are inserted at the corners of the duct. This may include spot welding of angle pieces (16), (18) to the peripheries of the flange section 3c or introduction of pieces 19, 20 into the cavities of the flange section. Outer ends (19c), (20c), Figs. 11, 12 (not shown), prevent lugs (19a), (20a) sliding into the cavities. Connecting screws (not shown) may be used to rigidly fix the angle pieces. |
