GB1368143A - Metal strap welding apparatus - Google Patents

Abstract

1368143 Welding by pressure TOYO KOHAN CO Ltd and TOA SEIKI CO Ltd 1 Dec 1971 [25 Dec 1970] 55673/71 Heading B3R An apparatus for welding overlapped portions of a metal strap located about an article comprises a strap guide 41a for locating a strap to be welded, a first welding electrode 34, a support 36 for the first electrode movable arcuately between a free position and a pressure applying position and a second electrode 33 movable arcuately between a free position and a welding position opposite the first electrode in its pressure applying position. An automatic strapping machine includes an electrode mechanism 30, Fig. 2, a strap clamping mechanism 40 and a strap shearing mechanism 50 in chambers 23, 24, 25 between end plates 26, 29 secured by a bolt 38 and end plates 21, 22. The mechanism 30 includes a bell crank 36, Fig. 3, carrying a rotatable adaptor 35 supporting two spaced electrodes 34, the crank being rotatable about a pivot 37 by an hydraulic ram 39. A second chisel like electrode 33 is carried on an arm pivoted on the bolt 38 and an arcuate slot in the arm is engaged by a pin 32. The mecha nism 40 in chambers 24 between two plates 27, 28 comprises a pair of clamp members 41, Fig. 4, carried by levers operated by an hydraulic ram 44 through a linkage including a link 43 pivoted to the pin 32. The mechanism 50 includes a blade 52 caused to exert vertical reciprocation by an hydraulic ram operating through a linkage. In operation with one end of a metal strap beneath a bridge member 51 and the other end over the member 51 and both ends over the guide 41a the ram 44 is operated to cause the members 41 to clamp the strap ends against the bottom edge of the plate 28, movement of the link 43 causing the pin 32 to move in the arcuate slot in the arm of the second electrode 33 and then to cause movement of the electrode 33 beneath the strip ends. The ram 39 is operated to move the electrode 34 into pressure applying engagement with the strip ends and spot welding is effected. After withdrawal of the members 41 and of the electrodes the blade 52 is caused to descend to sever the upper strip end in cooperation with the bridge 51.