# US 2010/0163603 A1 · Advanced multi-shouldered fixed bobbin tools for simultaneous friction stir welding of multiple parallel walls between parts > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0163603 A1 - Document ID: US20100163603A1 - Status: Published application - Kind: A1 - Application number: 12/601,501 - Filed: 2009-03-16 - Published: 2010-07-01 - Earliest claimed: 2008-03-14 - Assignees: Alcoa Inc. - Inventors: Israel Stol; John W. Cobes; Trent A. Chontas; Joseph M. Fridy - Web page: https://patentgrep.com/patent/US20100163603A1 ## CPC - B23K 20/125: {Rotary tool drive mechanism} - B23K 2101/045: {Hollow panels} - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM ## Abstract A multi-shouldered friction stir welding tool (10) comprises an integral shank-pin unit (11) having a plurality of pin portions on the shank-pin unit, where the plurality of pin portions for driving into a plurality of joints to perform a friction stir welding operation on the corresponding plurality of joints and, where a shank portion of the shank-pin unit is for attachment to an optional axial tension rod (19), each of the friction stir welding modules comprises a pair of shoulders (13, 14) that is connected to the shank-pin unit where each shoulder has a distal end and a proximal end, where the proximal end of each shoulder faces the pin portion of the shank-pin unit, whereby the shoulder and pin(s) rotate in unison, and a pair of split collars or a pair of nuts that is connected to the shank-pin unit and faces the distal end of each shoulder, where the plurality of friction stir welding modules are connected to each other whereby the modules rotate in unison to simultaneously make a plurality of parallel welds. In addition, a method of friction stir welding a plurality of joints simultaneously comprising using at least one multi-shouldered friction stir welding tool is provided. ## Claims ### Claim 1 A multi-shouldered friction stir welding tool comprising: a dual shoulder monolithic shoulder-pin unit having a pair of opposingly oriented shoulders with a pin portion of a predetermined length disposed therebetween, and a bore-hole through the pair of opposingly oriented shoulders and the pin portion, wherein each shoulder of the pair of opposingly oriented shoulders includes an end having a recess therein, wherein at least one recess being threaded; a single shoulder monolithic shoulder-pin unit having a shoulder, a pin portion, and a bore-hole through the shoulder and the pin portion, wherein the shoulder includes an end having a threaded recess therein, wherein a portion of the pin portion is threaded; a coupler having a first threaded end, a second threaded end, and a bore-hole therethrough, wherein the first threaded end being operably compatable with the threaded recess of the dual shoulder monolithic shoulder-pin unit and the second threaded end being operably compatable with the threaded recess of the single shoulder monolithic shoulder-pin unit; and a monolithic shoulder/shank unit having a shoulder and a bore-hole therethrough, wherein a portion of the bore-hole is threaded and operably compatable with the threaded portion of the pin such that an adjustable gap is formed between the shoulder of the monolithic shoulder/shank unit and the shoulder of the single shoulder monolithic shoulder-pin unit when the single shoulder monolithic shoulder-pin unit is rotated relative to the monolithic shoulder/shank unit, whereby a plurality of work pieces of same or different thicknesses can be simultaneously welded. ### Claim 2 (depends on 1) The multi-shouldered friction stir welding tool according to claim 1 further comprising (i) a tension rod operably connected to the pin portions of the dual shoulder monolithic shoulder-pin unit and the single shoulder monolithic shoulder-pin unit to apply a compression load onto the pin portions when the tension rod is placed in tension, and (ii) a tension rod load applying mechanism connected to the tension rod to place the tension rod in tension. ### Claim 3 (depends on 1) The multi-shouldered friction stir welding tool according to claim 1 further comprises a coupler self locking mechanism. ### Claim 4 (depends on 3) The multi-shouldered friction stir welding tool according to claim 3 wherein the coupler self locking mechanism comprises a thread orientation of the first threaded end of the coupler and the threaded recess of the dual shoulder monolithic shoulder-pin unit being oppose a thread orientation of the second threaded end of the coupler and the threaded recess of the single shoulder monolithic shoulder-pin unit such that as the multi-shouldered friction stir welding tool rotates during the friction stir welding operation the coupler tightens within the dual shoulder monolithic shoulder-pin unit and the single shoulder monolithic shoulder-pin unit. ### Claim 5 (depends on 2) The multi-shouldered friction stir welding tool according to claim 2 further comprises a torque release mechanism operably connected to the tension rod and to the dual shoulder monolithic shoulder-pin unit to release the tension rod from the dual shoulder monolithic shoulder-pin unit when the torsional load exceeds fatigue capability of the dual shoulder monolithic shoulder-pin unit or the single shoulder monolithic shoulder-pin unit. ### Claim 6 (depends on 1) The multi-shouldered friction stir welding tool according to claim 1 further comprises a lock nut threaded onto the threaded portion of the pin portion of the single shoulder monolithic shoulder-pin unit into an abutting relationship with the monolithic shoulder/shank unit. ### Claim 7 A multi-shouldered friction stir welding tool comprising: an exterior threaded solid pin having a diameter and a length; a shoulder having a threadless inner diameter slightly larger than the diameter of the exterior threaded solid pin and at least one substantially radial threaded set screw hole; an monolithic shoulder-shank having a threadless inner diameter slightly larger than the diameter of the exterior threaded solid pin and at least one substantially radial threaded set screw hole; a pair of locking nuts having a threadless outer diameter and a threaded inner diameter operably compatible with the exterior threaded solid pin, wherein the shoulder and the monolithic shoulder-shank are capable of slidable engagement with the exterior threaded solid pin along the length of the exterior threaded solid pin to set a space slightly larger than a thickness of a work piece to be welded. ### Claim 8 (depends on 7) The multi-shouldered friction stir welding tool according to claim 7 further comprises a lock nut threaded onto the exterior threaded solid pin into an abutting relationship with the shoulder. ### Claim 9 (depends on 7) The multi-shouldered friction stir welding tool according to claim 7 further comprises a lock nut threaded onto the exterior threaded solid pin into an abutting relationship with the monolithic shoulder-shank. ### Claim 10 (depends on 7) The multi-shouldered friction stir welding tool according to claim 7 further comprises substantially radial set screws to connect the shoulder and the monolithic shoulder-shank to the pair of locking nuts. ### Claim 11 A multi-shouldered friction stir welding tool comprising: an integral shank-pin unit having a plurality of pin portions on the shank-pin unit, wherein the plurality of pin portions for driving into a plurality of joints to perform a friction stir welding operation on the corresponding plurality of joints and, wherein a shank portion of the shank-pin unit is for attachment of an optional axial tension rod, a plurality of friction stir welding modules, each of the friction stir welding modules comprising: a pair of shoulders that is connected to the shank-pin unit where each shoulder has a distal end and a proximal end, where the proximal end of each shoulder faces the pin portion of the shank-pin unit, whereby the shoulder and pin(s) rotate in unison; and a pair of split collars or a pair of nuts that is connected to the shank-pin unit and faces the distal end of each shoulder; wherein the plurality of friction stir welding modules are connected to each other whereby the modules rotate in unison to simultaneously make a plurality of parallel welds. ### Claim 12 (depends on 11) The multi-shouldered friction stir welding tool of claim 11 wherein the axial tension rod is disposed within the shank portion of the shank-pin unit. ### Claim 13 (depends on 12) The multi-shouldered friction stir welding tool of claim 12 wherein the shank-pin unit contains a loading means for placing the axial tension rod in tension and the shank-pin in compression. ### Claim 14 (depends on 11) The multi-shouldered friction stir welding tool of claim 11 wherein the shank-pin unit has threadless ends with at least two flats along the length of the shank-pin unit. ### Claim 15 (depends on 11) The multi-shouldered friction stir welding tool of claim 11 wherein each shoulder has an opening to facilitate contact with threads on the shank-pin unit. ### Claim 16 (depends on 11) The multi-shouldered friction stir welding tool of claim 11 further comprising each split collar has a threaded outer diameter and a threaded inner diameter that is connected to the shank-pin unit by threading the outer diameter of the collar onto threads on an inner diameter of the shoulder and threading the inner diameter of the collar onto threads on an outer diameter of the shank-pin unit. ### Claim 17 (depends on 16) The multi-shouldered friction stir welding tool of claim 16 wherein each split collar is further tightened against or connected to the shank-pin unit by screws. ### Claim 18 (depends on 11) The multi-shouldered friction stir welding tool of claim 11 further comprising each nut has a threaded outer diameter and a threaded inner diameter that is connected to the shank-pin unit by threading the outer diameter of the nut onto threads on an inner diameter of a shoulder and threading the inner diameter of the nut onto threads on an outer diameter of the shank-pin unit. ### Claim 19 (depends on 18) The multi-shouldered friction stir welding tool of claim 18 wherein each nut is further tightened against or connected to the shank-pin unit by screws. ### Claim 20 (depends on 19) The multi-shouldered friction stir welding tool of claim 19 wherein each nut is further connected to the shank-pin unit by jam nuts. ### Claim 21 (depends on 11) The multi-shouldered friction stir welding tool of claim 11 wherein the shoulder may be a drive shank with an integrated shoulder. ### Claim 22 (depends on 13) The multi-shouldered friction stir welding tool of claim 13 wherein the loading means for placing the axial tension rod in compression is a bearing disposed in a shank-pin unit end for disengaging and relieving the torque experienced by the pin portions of the shank-pin unit during the friction stir welding operation. ### Claim 23 (depends on 16) The multi-shouldered friction stir welding tool of claim 16 wherein the distal end of the shoulder and the threaded outer diameter of the collar create a small pocket to prevent the plasticized material from flowing out of the joint. ### Claim 24 (depends on 11) A method of friction stir welding a plurality of joints simultaneously comprising using at least one multi-shouldered friction stir welding tool of claim 11. ### Claim 25 (depends on 24) The method of claim 24 wherein two multi-shouldered friction stir welding tools are simultaneously driven by a rotation-splitting transmission system. ### Claim 26 (depends on 24) The method of claim 24 wherein two multi-shouldered friction stir welding tools are simultaneously driven by two synchronized servo controlled motors. ### Claim 27 (depends on 11) The multi-shouldered friction stir welding tool of claim 11 wherein the shank-pin is made of a solid rod.