Method of, and machine for making a spiral decorative element of metal

Abstract

A method of making a so called pine-cone spiral decorative element of metal, which is formed from a plurality of bars, generally four or eight in number, having circular or polygonal cross-section, cut in desired length, comprises steps of bending each bar, whose end sections remain straight; welding the end sections of the bars at both their ends, which are placed side by side and angularly spaced so that the bars look like meridians of an unfinished product formed according to a rotation body; and mutual rotation of the one welded ends of the bars to the other ends thereof by a desired angle. Further, a machine for embodying the method of the invention is disclosed.

1 . A method of making a so called pine-cone spiral decorative element of metal, which is formed from a plurality of bars, generally four or eight in number, having circular or polygonal cross-section, cut in desired length, characterized by comprising steps of: 
 bending each bar, whose end sections remain straight;    welding the end sections of the bars at both their ends, which are placed side by side and angularly spaced so that the bars look like meridians of an unfinished product formed according to a rotation body;    mutual rotation of the one welded ends of the bars to the other ends thereof by a desired angle.    
     
     
         2 . A method according to  claim 1 , characterized in that such a mutual rotation is performed in only a direction, with a result that the one welded ends approach the other welded ends.  
     
     
         3 . A method according to  claim 2 , characterized in that such a rotation is performed by a multiple of 90 degrees, except for a spring-back depending on the material.  
     
     
         4 . A method according to  claim 1 , characterized in that such a mutual rotation comprises a first rotation in a direction, followed by a second rotation in a direction opposite to the first one, with a result that the one welded ends approach the other welded ends.  
     
     
         5 . A method according to  claim 4 , characterized in that said second rotation extends by an angle smaller than the first rotation and is offset to the same by a multiple of 90 degrees, except for a spring-back depending on the material.  
     
     
         6 . A machine for making a so called pine-cone spiral decorative element of metal, characterized in that the machine is a composite machine comprising: 
 a horizontal press provided with a die and a counter-die to obtain on a bar a bend with straight end sections; and    a twisting machine, having a body provided with a free upper surface adapted to sustain the horizontal press, body from which an elongated prismatic bench extends, on which there are mounted in a displaceable and releasable way a screw device, which is connected, on one hand, by a mandrel to a drive of the twisting machine, and, on its other hand, is provided of a housing to house the one welded ends of end sections of bars, and a vise, designed to clamp the other welded ends of end sections of bars.