Patent GB-1280526-A (GB)
Title: Method of and apparatus for forming metal ribbon
Inventor: LANDIS GEORGE GIDEON
IPC: B21B37/50
Filed: 1969-07-08
Abstract: 1280526 Rolling metals LINCOLN ELECTRIC CO 8 July 1969 34303/69 Heading B3M A metal ribbon to be formed into a tubular welding electrode is produced by rolling a longitudinally extending groove in one side only of a rod and then widening and optionally deepening the groove until a ribbon is formed of uniform thickness across its width. The general arrangement of the apparatus is shown in Fig. 1. Fully annealed steel in the form of green rod passes from a coil 10 through straightening rolls 12 and a sizing die to a series of pairs of forming rolls 14-14<SP>1</SP>; 16-16<SP>1</SP>; ... 22-22<SP>1</SP> each pair being separated by one of idler rollers 15-17 which are supported below the level of the forming rollers. The ribbon leaving the last pair of forming rolls is in the form of a V-shaped ribbon which is filled from a hopper 16 the surplus then being removed by a scraper 9. The tube is then closed by rolls 14, passed through a sizing die and coiled. The purpose of the idler wheels is to ensure that the rod is in sufficient contact with the lower of the forming rolls to locate it accurately. The pairs of forming rolls are driven by individual motors 40 possibly through differentials to allow for the different effective diameters of the upper and lower rollers. The speed of each motor may also be controlled in accordance with the sag of the idler preceding it so as to control the slack between the stages. Roller details.-A series of profiles of a rod undergoing the fire stage process of Fig. 1 is shown in Figs. 2-11 (not shown) but in Figs. 12-15 are shown the processes of a three stage rod reduction. Fig. 12 shows the forming rod resting on the groove in the lower roller 81. The radius of curvature of the curved bottom is so chosen that the rod touches it at two points 86. The first upper forming roll 90 shown in Fig. 13 has a V-shaped profile with a curved bottom which splits the upper surface of the rod on the centre line and the force is transmitted to points 86 which are sufficiently far apart to maintain the rod in position. A the same time there is very little longitudinal extension of the rod. The rod is thus given a V-shaped profile 93 with side walls of increasing thickness. This increase is reduced by a roll 102 (Fig. 14) which increases the sideways extension at the same time, the lower roll profile remaining unchanged. In a third pass the roll 116 (Fig. 5) makes the ribbon of uniform thickness and gives it the general C- shape shown. The arms of the C are brought together by further rollers operating inside the arms of the C (Figs. 16 and 17, not shown). The internal wall of the C is in tension so that when the C is shaped in a sizing die (Fig. 18) the ends of the C are pressed against each other. In further embodiments described with reference to Figs. 19 to 22 (not shown) the profile of the upper roller is such as to reduce each part of the ribbon to approximately its final thickness, the next roller reducing a further area outwardly from the centre in the next pass and so on.