Method for Forming an U-shaped Metal Frame

Abstract

A method for forming an U-shaped metal frame includes a preparing means: bend forming a straight tube in a continuous curve shape to be a billet including a spaced section and a first and a second side segments twisted toward opposite directions individually; a forming means: placing the billet into a cavity of a forming mold, closing two ends of the billet, and feeding a high-pressure fluid into the billet; a cutting means: cutting the billet into the first and the second pipes, the first pipe including a first connecting portion formed in a first cut position thereof, the second pipe including a second connecting portion formed in a second cut position thereof; a connecting means: twisting the first side segment and the second side segment toward the same direction, and connecting the first connecting portion and the second connecting portion together to obtain the U-shaped metal frame.

1 . A method for forming an U-shaped metal frame comprising:
 a preparing means: bend forming a straight tube in a continuous curve shape to be a billet of the metal frame, and the billet including a spaced section and a first and a second side segments twisted toward opposite directions individually;   a forming means: placing the billet of the metal frame into a cavity of a forming mold, and closing two ends of the billet, and then feeding a high-pressure fluid into the billet so that a concave or convex cross section is formed on the billet;   a cutting means: cutting the billet into a first and a second pipes, and the first pipe including a first connecting portion formed in a first cut position thereof, and the second pipe including a second connecting portion formed in a second cut position thereof;   a connecting means: twisting the first side segment of the first pipe and the second side segment of the second pipe toward the same direction, and connecting the first connecting portion of the first pipe and the second connecting portion of the second pipe together to obtain the U-shaped metal frame.   
     
     
         2 . The method for forming the U-shaped metal frame as claimed in  claim 1 , wherein the straight tube is bent by a tube bending machine to form a continuously curved billet in preparing means. 
     
     
         3 . The method for forming the U-shaped metal frame as claimed in  claim 1 , wherein the forming mold is split along a curved axial line of the billet in the forming means. 
     
     
         4 . The method for forming the U-shaped metal frame as claimed in  claim 1 , wherein the cavity of the forming mold includes two punching heads disposed on two sides thereof respectively to close the two ends of the billet. 
     
     
         5 . The method for forming the U-shaped metal frame as claimed in  claim 4 , wherein in the forming means, the concave or convex cross section is formed on the billet by using a fluid forming method, the fluid forming method includes placing the billet of the metal frame into the cavity of the forming mold, and the punching heads of the cavity are used to close the two ends of the billet, the high-pressure fluid is fed into the billet directly so that the billet of the metal frame is inflated in the cavity by using a pressure of the high-pressure fluid, and then the concave or convex cross section is formed on the billet. 
     
     
         6 . The method for forming the U-shaped metal frame as claimed in  claim 4 , wherein in the forming means, the concave or convex cross section is formed on the billet by using a heat treating method, the heat treating method includes pre-heating the billet of the metal frame to a suitable thermoplastic temperature and then placing the billet into the cavity of the forming mold, the forming mold is heated to be at the suitable thermoplastic temperature, and the punching heads of the cavity are applied to close the two ends of the billet, a high-pressure air is further fed into the billet so that the billet of the metal frame is inflated by a pressure of the high-pressure air, hence the concave or convex cross section is formed on the billet. 
     
     
         7 . The method for forming the U-shaped metal frame as claimed in  claim 1 , wherein in the forming means, the spaced section of the billet includes an expanding portion formed thereon, the first side segment includes a first recessed part formed thereon, and the second side segment includes a second recessed part formed thereon. 
     
     
         8 . The method for forming the U-shaped metal frame as claimed in  claim 7 , wherein in the cutting means, rest materials of the first and the second side segments are cut, and the expanding portion of the spaced section is cut so that the billet of the metal frame is separated into the first pipe and a second pipe. 
     
     
         9 . The method for forming the U-shaped metal frame as claimed in  claim 7 , wherein in the cutting means, rest materials of the first and the second side segments are cut, and a certain position between the expanding portion of the spaced section and a curved corner of the spaced section is cut so that the billet of the metal frame is separated into the first pipe and the second pipe. 
     
     
         10 . The method for forming the U-shaped metal frame as claimed in  claim 1 , wherein in the connecting means, the first and the second connecting portions include an equal diameter, and the first connecting portion of the first pipe and the second connecting portion of the second pipe are connected with each. 
     
     
         11 . The method for forming the U-shaped metal frame as claimed in  claim 10 , wherein the first connecting portion of the first pipe and the second connecting portion of the second pipe are connected together to form a connection therebetween, and then the connection of the first and the second connecting portions is welded, thereafter a first weld head is used to fix the first and the second pipes. 
     
     
         12 . The method for forming the U-shaped metal frame as claimed in  claim 10 , wherein the first connecting portion of the first pipe and the second connecting portion of the second pipe are connected together to form a connection therebetween, and then a connector is fixed to the connection of the first and the second connecting portions, thereafter the first and the second connecting portions are fixed by first screw elements individually. 
     
     
         13 . The method for forming the U-shaped metal frame as claimed in  claim 1 , wherein in the connecting means, the first and the second connecting portions include different diameters respectively, and the first connecting portion of the first pipe and the second connecting portion of the second pipe are connected with each. 
     
     
         14 . The method for forming the U-shaped metal frame as claimed in  claim 13 , wherein a punching head is used to punch a hole with an increased diameter on the first connecting portion of the first pipe, and the first connecting portion of the first pipe is fitted with the second connecting portion of the second pipe, then a fitting position of the first and the second connecting portions is welded, thereafter a second weld head is applied to fix the first and the second pipes together. 
     
     
         15 . The method for forming the U-shaped metal frame as claimed in  claim 13 , wherein a punching head is used to punch a hole with an increased diameter on the first connecting portion of the first pipe, and the first connecting portion of the first pipe is fitted with the second connecting portion of the second pipe, then a second screw element is screwed into the fitting position of the first and the second connecting portions. 
     
     
         16 . The method for forming the U-shaped metal frame as claimed in  claim 13 , wherein a punching head is used to punch a hole with an increased diameter on the first connecting portion of the first pipe, and the first connecting portion of the first pipe is fitted with the second connecting portion of the second pipe, then a bonding agent is applied onto the fitting position of the first and the second connecting portions so that the first and the second pipes are adhered together. 
     
     
         17 . The method for forming the U-shaped metal frame as claimed in  claim 1 , wherein in the forming means, the spaced section of the billet includes a first recessed part and a second recessed part formed thereon, and the first side segment includes an expanding portion formed thereon. 
     
     
         18 . The method for forming the U-shaped metal frame as claimed in  claim 17 , wherein in the cutting means, a central portion of the spaced portion is cut into the first pipe and the second pipe, and one side of the expanding portion of the first pipe is cut to eliminate rest material, thus forming a first connecting portion, and one side of the second side segment of the second pipe is cut to eliminate rest material, forming a second connecting portion. 
     
     
         19 . The method for forming the U-shaped metal frame as claimed in  claim 1 , wherein in the forming means, the spaced section of the billet includes a first recessed part and a second recessed part formed thereon, and the first side segment includes a first expanding portion formed thereon, the second side segment includes a second expanding portion formed thereon. 
     
     
         20 . The method for forming the U-shaped metal frame as claimed in  claim 19 , wherein in the cutting means, a central portion of the spaced portion is cut into the first pipe and the second pipe, and one side of the first expanding portion of the first pipe is cut to eliminate rest material, thus forming a first connecting portion, and one side of the second expanding portion of the second pipe is cut to eliminate rest material, forming a second connecting portion.