Patent ID: 7942306
Filing Date: 2011-05-17
Classification: B23K

Abstract:
1. A tool for forming a friction stir weld joint in a workpiece, the tool comprising: a support body rotable about a first axis, the support body having a shoulder; a pin extending from said shoulder, said pin having a peripheral surface with an angle αrelative to said first axis; a first geometric feature on said peripheral surface of said pin comprising a plurality of tapered flats, wherein each of said plurality of tapered flats is angled at an angle relative to said first axis, said angle of each of said plurality of tapered flats being larger than said angle α, and wherein said plurality of tapered flats is adapted to promote a flow of weld material away from said shoulder; a second geometric feature on said peripheral surface of said pin comprising at least one counter-spiraling channel or thread on said pin's peripheral surface, said second geometric feature adapted to promote a flow of weld material toward said shoulder, and said second geometric feature overlapping with said first geometric feature such that said second geometric feature and said first geometric feature overlap by different amounts on different sections of said peripheral surface along a length of said pin.