It is known in the manufacture of motor vehicles to form tubular structures such as roof rails and frame rails and other parts by capturing a tube with a die cavity, sealing the ends of the tube, and introducing pressurized fluid to expand the tube into a shape defined by the die cavity. In the interest of economies of manufacture, it is desirable to perform additional operations on the hydroformed part such as the punching of holes while the part is still captured within the die and subject to internal pressure by the pressurized fluid.
It would be desirable to provide a new and improved apparatus for using a single punch to punch a first hole in one wall of the tube and having that same punch travel across the inside of the tube and punch a second hole in the other wall of the tube.
USPTO Backgrounds
USPTO Backgrounds