Method of connecting metal strips

Abstract

A trailing end of a first metal strip is connected to a leading end of a second metal strip in a strip-treatment plant by first forming at least one of the strips as a cold-rolled, non-annealed metal strip and then superposing the trailing end of the first strip and the leading end of the second strip at an overlap. Then the strips are connected at the overlap at at least 20 connection points per meter of the strips by clinching without through cutting.

We claim: 
     
         1 . A method of connecting a trailing end of a first metal strip to the leading end of a second metal strip in a strip-treatment plant, the method comprising the steps of:
 forming at least one of the strips as a cold-rolled, non-annealed metal strip;   superposing the trailing end of the first strip and the leading end of the second strip at an overlap; and   connecting the strips at the overlap at at least 20 connection points per meter of the strips by clinching without through cutting.   
     
     
         2 . The strip-connecting method defined in  claim 1 , wherein the first strip and/or the second strip is/are formed of aluminum, an aluminum alloy, copper, or a copper alloy. 
     
     
         3 . The strip-connecting method defined in  claim 1 , wherein the material of the metal strips has a stretch at break A80 of a maximum of 6%. 
     
     
         4 . The strip-connecting method defined in  claim 3 , wherein the stretch at break is 2% to 5%. 
     
     
         5 . The strip-connecting method defined in  claim 3 , wherein the stretch at break is 3% to 4%. 
     
     
         6 . The strip-connecting method defined in  claim 1  wherein at least 30 connection points per meter are set by clinching. 
     
     
         7 . The strip-connecting method defined in  claim 1 , wherein at least 50 connection points per meter are set by clinching. 
     
     
         8 . The strip-connecting method defined in  claim 1 , further comprising the step of:
 measuring the thickness of the trailing end of the first and/or of the second metal strip before connection; and   controlling the clinching process as a function of the measured thickness or thicknesses.   
     
     
         9 . The strip-connecting method defined in  claim 8 , wherein the clinching process is controlled by controlling a depth of insertion of a clinching tool as a function of the measured thickness or thicknesses. 
     
     
         10 . The strip-connecting method defined in  claim 9 , wherein the depth is increased as the measured thickness or thickness increases. 
     
     
         11 . The strip-connecting method defined in  claim 1 , further comprising the step of:
 restricting the connections points to an inner region of the strips inwardly offset from side edges of the strips.   
     
     
         12 . The strip-connecting method defined in  claim 11 , further comprising the step of:
 trimming the side edges of the strips after setting the connection points.   
     
     
         13 . The strip-connecting method defined in  claim 1 , further comprising, when one of the strips is above the other of the strips at the overlap, the steps of:
 lubricating only an upper face of the one strip and a lower face of the other strip prior to clinching together while excluding lubrication of a lower face of the one strip and an upper face of the other strip such that there is no lubrication between the strips at the overlap.