초록 ▼

The present invention relates to a method and apparatus for forming an elongated tubular metal member from a tubular metal blank. The method comprises: i) placing a tubular metal blank having a generally oval cross-section into a die cavity and orienting the tubular metal blank such that a relativel

The present invention relates to a method and apparatus for forming an elongated tubular metal member from a tubular metal blank. The method comprises: i) placing a tubular metal blank having a generally oval cross-section into a die cavity and orienting the tubular metal blank such that a relatively larger cross-sectional dimension of the generally oval cross-section extends generally in a direction of the relatively larger cross-sectional dimension of the die cavity and such that a relatively smaller cross-sectional dimension of the generally oval cross-section extends generally in a direction of the relatively smaller cross-sectional dimension of the die cavity; ii) engaging and sealing opposite ends of the tubular metal blank; and iii) injecting fluid under pressure into the tubular metal blank so as to expand the tubular metal blank into conformity with the surfaces defining the die cavity and thereby transform the tubular metal blank into the elongated tubular metal member.

대표청구항 ▼

[ What is claimed is:] [1.] A method of forming an elongated tubular metal member having a cross-sectional configuration such that it includes a first cross-sectional dimension which is greater than a second cross-sectional dimension orthagonal to said first cross-sectional dimension, said method ut

[ What is claimed is:] [1.] A method of forming an elongated tubular metal member having a cross-sectional configuration such that it includes a first cross-sectional dimension which is greater than a second cross-sectional dimension orthagonal to said first cross-sectional dimension, said method utilizing a die assembly having first and second die structures having surfaces cooperable to define a die cavity having a first cross-sectional dimension which is greater than a second cross-sectional dimension generally orthagonal to said first cross-sectional dimension, said die cavity having a closed box cross-sectional configuration, said method comprising:roll-forming sheet metal to form a tubular metal blank having an oval cross-section, said oval cross-section including a major axis along a greater diameter thereof and a minor axis along a smaller diameter thereof, said major and minor axes being generally orthagonal to one another;placing the tubular metal blank into said second die structure, said second die structure being constructed and arranged to receive the tubular metal blank having said oval cross-section without distorting said tubular metal blank from its oval cross-section, said tubular metal blank being placed into said second die structure such that said major axis of said oval cross-section thereof extends in generally the same direction as said first cross-sectional dimension when said first and second die structures cooperate to form said die cavity and such that said minor axis of said oval cross-section thereof extends in generally the same direction as said second cross-sectional dimension of said die cavity when said first and second die structures cooperate to form said die cavity, said tubular metal blank having a diameter along said minor axis thereof which approximates said second cross-sectional dimension of said die cavity;engaging opposite ends of the tubular metal blank with tube-end engaging structures so as to substantially seal opposite ends of the tubular metal blank;closing the die assembly; andinjecting fluid under pressure into the tubular metal blank placed in the die cavity to expand the tubular metal blank into conformity with the surfaces defining the die cavity.