Production method of multi-gauge strips

Abstract

The present invention provides a method of producing a multi-gauge strip which has a thick portion and a thin portion which are continuously disposed along its length. The method of producing multi-gauge strips consisting of a relatively thick portion and a relatively thin portion formed along the widthwise direction while continuously transferring a strip material, is characterized by comprising the steps of: primarily forming a strip material by pressing the upper side thereof so as to make a groove in the lower side of the part where a thin portion is to be formed; and secondly forming the resulted strip by pressing the upper side of the primarily formed strip so as to form the part having a groove into a thin portion and the other part into a thick portion.

1 . A method of producing multi-gauge strips consisting of a relatively thick portion and a relatively thin portion formed along the widthwise direction while continuously transferring a strip material, characterized by comprising the steps of:
 primarily forming a strip material by pressing the upper side thereof so as to make a groove in the lower side of the part where a thin portion is to be formed; and secondly   forming the resulted strip by pressing the upper side of the primarily formed strip so as to form the part having a groove into a thin portion and the other part to a thick portion.   
   
   
       2 . The method of producing multi-gauge strips according to  claim 1 , wherein the groove formed in the primary forming step is in the shape of a trapezoid or curved surface. 
   
   
       3 . The method of producing multi-gauge strips according to  claim 1 , wherein the primary forming step comprises formation of the strip material into a processed strip which has a thick portion formed at the center in the widthwise direction of the strip, and a groove formed in each end of the lower side; and the second forming step comprises formation of the processed strip into a multi-gauge strip consisting of a thick portion in the center and a thin portion at each end of the thick portion. 
   
   
       4 . The method of producing multi-gauge strips according to  claim 3 , wherein the second forming step comprises formation of a W-shaped multi-gauge strip by forming a square-shaped depressed area at the center in the upper part of the thick portion. 
   
   
       5 . The method of producing multi-gauge strips according to  claim 1 , wherein the primary forming step comprises formation of a strip material into a processed strip which has a multiple number of grooves in the lower side thereof and a thick portion between said grooves; and second forming step comprises formation of the processed strip into a multi-gauge strip consisting of a multiple number of thick portions and thin portions therebetween, by forming the grooves in the inner part of the processed strip into a thin portion and then simultaneously forming the grooves at each end part into a thin portion. 
   
   
       6 . The method of producing multi-gauge strips according to  claim 5 , wherein the formation of the grooves in the inner part into a thin portion in the second forming step, is conducted subsequently in order of grooves in the center and outward grooves. 
   
   
       7 . The method of producing multi-gauge strips according to  claim 1 , wherein the primary forming step comprises formation of a strip material into a processed strip having grooves formed in each side of the protrusion at the center of the lower side, and a thick portion formed outside of the grooves; and a second forming step comprises formation of the processed strip into a multi-gauge strip consisting of thick portions at each end thereof and a thin portion between the thick portions.