GB723908A - An improved machine for producing lock seamed tubing - Google Patents

Abstract

723,908. Making seamed tubing. LAWRENCE, J. W. April 24, 1953 [March 6, 1952], No. 5889/52. Classes 83 (2) and 83 (4). Drawing.-A machine for producing lock seamed tubing comprises, in combination, a die head carrying fixed contoured dies between which an initially flat strip of thin metal can be drawn, the said dies converting the metal strip in progressive stages into lock seamed tubing and means for gripping and feeding forwards the finished tubing emerging from the die head and thereby continuously drawing the strip through said head in a straight path. The die head A comprises a trough 1 a following die unit 2 having a channel 5 and carrying opposed sets of die plates 6-12 clamped to the top surface of the unit. The trough 1 has inwardly directed flanges 1a which fold the copper strip 13 into a U-shaped formation, the strip being lubricated with oil, the surplus being collected in a drip-tray 15. As the folded strip issues from the trough the upper ends of the limbs 13a and 13b pass through the die plates which are contoured as shown in Figs. 4, 9 to 12 to progressively form the lock seamed joint. Extending through the channel 5 in the die unit 2 is a mandrel 21 about which the tubing T is formed. The end of the mandrel is attached to a lever 22 which inserts or extracts the mandrel into or from the channel 5, the mandrel being locked in position by a screw 25. A pair of knurled feed wheels 26 and 27 mounted between a base plate 28 and a superimposed plate 29 grip and feed forward the finished tubing T emerging from the die unit. The mandrel extends between the feed wheels to prevent crushing of the tube. The feed wheel 27 is driven from the wheel 26 through integral spur gears 32 and 31 respectively, the wheel 27 being driven by an electric motor. The spindle of the feed wheel 27 is mounted in adjustably spring-loaded bearing blocks .33 slidable in transverse slots 34 and 35 in the plates 28 and 29. From the feed wheels the tubing passes between pairs of straightening rolls 41 and 42, the rolls 42 being mounted on manually adjustable eccentrics. Between the die unit and the feed wheels there is pair of rollers 43, .44 which flatten the seam 13f and bring the tubing to the correct size. The bottom roller 43 is mounted in the die unit and the upper roller 44 is mounted in a spring-loaded adjustable block 48 which slides on vertical rods 51. The machine may include an automatic parting-off saw, a coil holder for the strip metal together with a tensioner and also tanks for flux and solder for tinning or soldering the strip metal. Alternatively, the feeding means may comprise an endless roller chain furnished with pairs of laterally spaced shoes arranged on opposite sides of the tubing issuing from the die unit. Specification 723,907 is referred to.