Patent ID: 9308577
Filing Date: 2016-04-12
CPC Classification: B21K,B60J,Y10T

Claim Text:
1. A method for manufacturing a vehicle door assembly comprising an inner panel in the form of a substantially rectangular perimeter frame portion having a continuous perimeter integrally formed by upper and lower horizontal beams interconnected by front and rear upright beams, said method comprising the steps of: providing front and rear flat U-shaped steel sheets of a first steel material, each of said left and right U-shaped steel sheets comprising a cross portion and a pair of spaced apart leg portions extending from said cross portion; providing top and bottom flat steel sheets of a second steel material; non-detachably connecting each of said leg portions of each of said U-shaped steel sheets to a respective one of said top and bottom steel sheets so as to form a flat door perimeter frame blank; and stamping said door perimeter frame blank into said perimeter frame portion of said inner panel; said first steel material of said front and rear flat U-shaped steel sheets being different from said second steel material of said top and bottom flat steel sheets; said frame portion comprising opposite front and rear U-shaped side frame members non-detachably attached to each other by upper and lower intermediate frame members so as to form said continuous perimeter; said side frame members made of said first steel material and said intermediate frame members made of said second steel material.