BONDING METHOD OF BINDING STRAP END PORTIONS BY SPOT-WELDING

摘要

BONDING METHOD OF BINDINGSPEND PORTIONS BY SPOT-WELDINGA B S T R A C TDisclosed is a method for binding overlapped endportions of a binding strap encircled about articles to bebound and tightened to a tensioned state by means of agripper disposed at a gripping station for gripping aleading end portion of the binding strap, and drive rollersdriven in their reverse mode so as to retract a trailing endportion of the binding strap, comprising the steps ofinterposing a plate electrode between the article beingbound and the overlapped portions of the binding strap,lowering a single electrode tip, disposed above theoverlapped portions of the binding strap into contact withthe overlapped portions of the binding strap such that thelatter is compressed between the electrode tip and the plateelectrode, and energizing the electrodes so as to perform aspot-welding operation at a first location, upon saidoverlapped portions of the binding strap, which is remotefrom the gripping station. The electrode tip is thenraised and moved to a second location closer to the grippingstation at which the electrode tip is again lowered intocontact with the overlapped portions of the binding strapsuch that the latter is again compressed between the twoelectrodes. Upon energization of the electrodes, a secondspot-welding operation is performed. A cutter disposed atthe gripping station is actuated, so as to sever thetrailing end portion of the binding strap from the residualsupply portion of the binding strap, either before or afterperformance of the second spot-welding operation. In eithercase, the second spot-welding operation is performed underessentially no-load or no-tension conditions.