Production method of offset-shaped fins, fins, and method and apparatus for changing pitch of fins

Abstract

An offset-shaped fin 4 can be continuously processed by roll molding by a method involving a first step of bending a flat sheet-like material 40 A into a concavo-convex shape by a pair of first rollers 5, 5 ′ to form a corrugate sheet 40 B; a second step of cutting slopes of the concavo-convex ridges of the corrugate sheet by a pair of second rollers; and a third step of bending the offset portion, offset and cut in the second step, by a pair of third rollers. A pitch-changing method of offset-shaped fins involves a step of supplying offset-shaped fins between at least one pair of pitch-changing rollers rotating while meshing with the other so that at least one pair of pitch-changing rollers clamp the offset-shaped fins between them, allow them to pass through said pitch-changing rollers and change their pitch.

1 . A production method of offset-shaped fins in which a plurality of concavo-convex ridges is so juxtaposed with one another as to repeat concavo-convexities and the positions of adjacent one of said concavo-convex ridges are offset in an extending direction of said concavo-convex ridges, comprising: 
 (1) a first step of bending a flat sheet-like material into a concavo-convex shape by a pair of first rollers having concavo-convex ridges formed on the surface thereof to form a corrugate sheet;    (2) a second step of cutting slopes of said concavo-convex ridges of said corrugate sheet by a pair of second rollers having cutting edges arranged in an offset arrangement; and    (3) a third step of bending said offset portion offset and cut in said second step by a pair of third rollers having concavo-convex ridges arranged in an offset arrangement on the surface thereof.    
   
   
       2 . A production method of offset-shaped fins according to  claim 1 , wherein an offset amount D of the cutting edges in said second step is set to about a sheet thickness so that penetrating the cut material into said rollers is approximate the same as the sheet thickness.  
   
   
       3 . A production method of offset-shaped fins according to  claim 1 , wherein gaps G are disposed between bent teeth offset and arranged in said third step so as to avoid contact of the material with said rollers.  
   
   
       4 . A production method of offset-shaped fins according to  claim 1 , wherein intermediate rollers for guiding said sheet material under molding are arranged between said first roller and said second roller and between said second roller and said third roller.  
   
   
       5 . Offset-shape fins produced by said production method of offset-shaped fins according to  claim 1 .  
   
   
       6 . A pitch-changing method of offset-shaped fins involving the steps of supplying offset-shaped fins between at least one pair of pitch-changing rollers each having a tooth shape formed on an outer periphery thereof and rotating while meshing with the other so that said at least one pair of pitch-changing rollers clamp said offset-shaped fins between them, allow them to pass through said pitch-changing rollers and change their pitch, wherein each tooth shape of said at least one pair of pitch-changing rollers is substantially similar to a profile shape of a transverse section of said offset-shaped fins on each roller side in a traveling direction of said offset-shaped pins after the pitch change by said one pair of pitch-changing rollers.  
   
   
       7 . A pitch-changing apparatus of offset-shaped fins including at least one pair of pitch-changing rollers each having a tooth shape formed on an outer periphery thereof and rotating while meshing with the other so that said at least one pair of pitch-changing rollers clamp said offset-shaped fins between them, allow them to pass through said pitch-changing rollers and change their pitch, wherein each tooth shape of said at least one pair of pitch-changing rollers is substantially similar to a profile shape of a transverse section of said offset-shaped fins on each roller side in a traveling direction of said offset-shaped fins after the pitch change by said one pair of pitch-changing rollers.