This invention is an apparatus for joining the ends of two cylindrical (i.e., pipe-shaped) sections together with a friction stir weld. The apparatus holds the two cylindrical sections together and provides back-side weld support as it makes a friction stir weld around the circumference of the joined ends

Carter, Robert W.

Ding, R. Jeffrey

NASA Technical Reports Server

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US006259052B3 
(12) United States Patent (io) Patent No.: US 6,259,052 B1 
Ding et al. (45) Date of Patent: Jul. 10,2001 
(54) 
(75) 
ORBITAL FRICTION STIR WELD SYSTEM 
Inventors: R. Jeffrey Ding, Athens, AL (US); 
Robert W. Carter, Columbus, OH 
(US) 
(73) Assignee: The United States of America as 
represented by the Administrator of 
the National Aeronautics and Space 
Administration, Washington, DC (US) 
Subject to any disclaimer, the term of this 
patent is extended or adjusted under 35 
U.S.C. 154(b) by 0 days. 
( * ) Notice: 
(21) Appl. No.: 09/216,484 
(22) Filed: Dec. 18, 1998 
(51) Int. Cl? ..................................................... B23K 11/00 
(52) U.S. C1. ........................ 219/59.1; 228125; 219178.01; 
2191125.11 
(58) Field of Search .............................. 228125, 4.1, 47.1, 
228148, 112.1, 114.5, 29, 44.5, 234.1, 2.1, 
2.3; 219156, 59.1, 60 A, 125.11 
I 
I 
I 
I 
55 J+ 
63 
60 
(56) References Cited 
U.S. PATENT DOCUMENTS 
3,741,555 * 611973 Roesel ............................... 266123 M 
3,777,101 * 1211973 Gwin et al. ........................ 219160 A 
3,841,547 * 1011974 Bartley ................................... 228129 
4,145,593 * 311979 Merrick et al. .................... 219160 A 
4,365,132 * 1211982 Kazlauskas et al. ............... 219160 A 
4,649,250 * 311987 Kazlauskas ........................ 219160 A 
5,844,190 * 1211998 Benway et al. .................... 219160 A 
* cited by examiner 
Primary Examinerqatrick Ryan 
Assistant E x a m i n e r a .  Alexandra Elve 
(74) Attorney, Agent, or Firm-Jerry L. Seemann 
(57) ABSTRACT 
This invention is an apparatus for joining the ends of two 
cylindrical (i.e., pipe-shaped) sections together with a fric- 
tion stir weld. The apparatus holds the two cylindrical 
sections together and provides back-side weld support as it 
makes a friction stir weld around the circumference of the 
joined ends. 
10 Claims, 5 Drawing Sheets 
https://ntrs.nasa.gov/search.jsp?R=20080004888 2019-08-30T02:55:03+00:00Z
U S .  Patent Jul. 10,2001 Sheet 1 of 5 US 6,259,052 B1 
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U S .  Patent Jul. 10,2001 Sheet 3 of 5 US 6,259,052 B1 
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U S .  Patent Jul. 10,2001 Sheet 4 of 5 US 6,259,052 B1 
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Fig. 4 
U S .  Patent Jul. 10,2001 Sheet 5 of 5 US 6,259,052 B1 
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ORBITAL FRICTION STIR WELD SYSTEM 
ORIGIN OF THE INVENTION 
clamping mechanism (20) for securing a cylindrical work 
piece (70), a weld head (30), a reaction support (40), a means 
for transmitting load from the weld head to the reaction 
The invention described in this patent was made by support (SO), and a means for rotating said weld head in 
employees of the United States ~~~~~~~~~t and may be s conjunction with said reaction support around the longitu- 
manufactured and used by or for the Government for gov- dinal axes Of said first and second clamping mechanisms 
ernmental purposes without the payment of any royalties. (60). 
The cylindrical clamping mechanism (20) has a longitu- 
BACKGROUND OF THE INVENTION dinal axis (21), is secured to the base frame (lo), and may 
10 consist of a variety of devices. A rudimentary clamping 
mechanism may consist of several set screws placed in a ring 
and secured. The mechanism shown in FIGS. 1 and 2 is a 
chuck similar to that used to hold material being worked on 
15 a machine such as a lathe. Obviously, other clamping 2. Background Information mechanisms may also be used. Since the cylindrical work 
Friction stir welding is a relatively new welding technique piece (70) will probably be in two sections, the cylindrical 
for joining like materials together. The friction stir technique clamping mechanism (20) must be capable of securing both 
uses a frictional heat source to plasticize adjoining sections sections of the work piece (70), Thus, in the preferred 
of the same material. Once plasticized, the frictional heat 2o embodiment, the cylindrical clamping mechanism (20) has 
spinning probe, which must be capab1e Of the the longitudinal axis (21) of the cylindrical clamping mecha- 
requisite plasticized temperatures, is commonly used as the nism (20) and separated by the weld head (30) and the 
frictional heat source. The spinning probe also facilitates reaction support (40). 
mixing of the material in the plasticized region. A more 25 
The weld head (30) and the reaction support (40) are complete description of friction stir welding can be found in 
rotationally mounted to the base frame (10) such that the U.S. Pat. No. 5,460,317. 
weld head (30) can rotate completely around the longitudi- 
nal axis (21) of the cylindrical clamping mechanism (20) Like most new techniques, friction stir welding is not 
and the reaction support (40) can be maintained in a position without its challenges. For example, significant forces are 
diametrically opposed to the weld head (30). In the preferred necessary for a spinning probe to penetrate and remain 30 within the sections of a work piece that are to be joined. As embodiment, rollers (24) are mounted on the cylindrical 
back side in order to make the friction stir weld possible or mechanism by which the weld head (30) and the reaction prevent unwanted damage to the work piece' Providing support (40) are rotated around the circumference of the 
back-side weld support can be nothing short of difficult with 3s cylindrical work piece (70), In essence, the cylindrical 
clamping mechanism (20) functions like a stationary inner particular work piece geometries. 
bearing race, the rollers (24) function like a bearing, and the 
weld head (30) and reaction support (40) function like a 
movable outer bearing race, 
The weld head (30) is also movable in a radial direction. 
This radial movement capability accommodates a variety of 
work piece sizes and is necessary for the friction stir weld 
process itself. The reaction support (40) also has a roller (41) 
to facilitate movement of the reaction support (40) around 
In the preferred embodiment, the means for transmitting 
load from the weld head to the reaction support (50) is a 
radial load bar (51) that is able to rotate and stay aligned with 
so the weld head (30) and the reaction support (40). Synchro- 
nized rotation (i.e., rotational alignment) may be accom- 
plished with a motor and gearing mechanism (similar to that 
The following discussion of the invention will refer to the used to rotate the weld head (30) and the reaction support 
(40) described below) and with a control mechanism that 
FIG. 1 represents a Perspective view ofthe orbital friction 55 coordinates the rotation of the radial load bar (51) with the 
weld head (30) and the reaction support (40). Dashed line 
FIG. 2 represents an elevation view of orbital friction stir (55) in FIG. 2 symbolically represents the rotational align- 
FIG. 3 represents a partial side view of the orbital friction Alternative embodiments for the load transmitting means 
60 include use of a wagon wheel brace (52) (see FIG. 4) or use 
FIGS. 4, 5a, and 5b represent alternative devices for of an inflatable bladder (53) reinforced with a metal band 
(54) (see FIGS. 5a and 5b). While the wagon wheel brace 
(52) and the inflatable bladder (53) are not preferred, the 
wagon wheel and bladder do not require rotational coordi- 
65 nation with the weld head (30) (i.e., the wagon wheel brace 
(52) and the inflatable bladder (53) remain in a stationary 
position relative to the weld head (30)). If the work piece 
1. Field of the Invention 
general, this invention pertains to friction stir welds, 
making a friction stir weld around the circumference of a 
cylindrical work piece. 
Specifically, this invention pertains to an apparatus for through which the cy1indrica1 piece (70) can be placed 
Source is removed and the sections join together. A a first part (22) and a second part (23) that are spaced along 
a the joint must be properly On the clamping mechanism (20). The rollers (24) provide the 
SUMMARY OF THE INVENTION 
This invention is an apparatus for joining the ends of two 
cylindrical (i.e., pipe-shaped) sections together with a fric- 40 
tion stir weld. The apparatus holds the two cylindrical 
sections together and provides back-side weld support as it 
makes a friction stir weld around the circumference of the 
joined ends. 
An object of this invention is to make a friction stir weld 45 the perimeter of the work piece (70), 
around the circumference of a cylindrical work piece. 
Another object of this invention is to provide back-side 
weld support when making a friction stir weld around the 
circumference of a cylindrical work piece. 
BRIEF DESCRIPTION OF THE DRAWINGS 
accompanying drawings in which: 
stir weld system. 
weld system. ment mechanism. 
stir weld system. 
providing back-side weld support. 
DESCRIPTION OF THE PREFERRED 
EMBODIMENT 
Referring to FIGS. 1,2, and 3, a preferred embodiment of 
this invention comprises a base frame (lo), a cylindrical 
US 6,259,052 B1 
3 4 
(70) is solid or has some other internal support system, the 
work piece (70) itself can transfer the load from the weld 
head (30) to the reaction support (40). 
Finally, referring again to FIG. 2, the means for rotating 
the weld head in conjunction with the reaction support 5 
around the longitudinal axis of the cylindrical clamping 
mechanism (60) includes a ring gear (61) that is attached to 
both the weld head (30) and the reaction support (40) and is 
drive gear (62) engaged with the ring gear (61); and a motor 
(63) for controlling the rotation of the drive gear (62). 
addition, a second ring gear (64) connected to a second drive 
gear (65) and a second motor (66) may be used to rotate the 
weld head (30) and the reaction support (40). The motors 
(63,66) can also be used to synchronize rotation of the radial 
load bar (51) with the weld head (30) and reaction support 
(40). Obviously, several other equivalent methods exist for 
controlling rotation of the weld head (30), the reaction 
support (40), and the radial load bar (51). 
An alternative embodiment of the invention comprises a 
cylindrical clamping mechanism (20) for securing a cylin- 2o 
drical work piece (70), a weld head (30), a reaction support 
(40), a means for transmitting load from the weld head to the 
reaction support (50), and a means for rotating said weld 
head in conjunction with said reaction support around the 
longitudinal axes of said first and second clamping mecha- 
nisms (60). This alternative embodiment is essentially the 
same as the preferred embodiment except for the base frame 
(lo), which has been eliminated. In the alternative 
embodiment, the cylindrical clamping mechanism functions 
as the base frame. As a result, this alternative embodiment 30 
produces a device which has increased portability. 
Operation of the invention is straightforward. Either the 
work piece is inserted into the cylindrical clamping mecha- 
nism or the cylindrical clamping mechanism is placed onto 
ment or the alternative embodiment is used, respectively. If 
needed, the load transmitting means (i.e., the radial load bar, 
the wagon wheel brace, the inflatable bladder, etc.) is 
positioned between the weld head and the reaction support. 
The weld head is then rotated around the weld head in order 40 ence of a cylindrical object, comprising: 
to make a friction stir weld. 
3. An apparatus for making a weld around the circumfer- 
ence of a cylindrical object, as recited in claim 1, wherein 
said weld head is movable in a radial direction relative to the 
longitudinal axis of said cylindrical clamping mechanism. 
4, ~n apparatus for making a weld around the circumfer- 
ence of a cylindrical object, as recited in claim 1, wherein 
said reaction 
ence of a cylindrical object, as recited in claim 1, wherein 
lo said means for transmitting load from said weld head to said 
reaction support, comprises: 
a radial load bar, said radial load bar extending between 
for synchronizing rotation of said radial load bar 
around the circumfer- 
ence of a cylindrical object, as recited in claim 1, wherein 
said means for transmitting load from said weld head to said 
reaction support comprises a wagon wheel brace, said 
wagon wheel brace is located between said weld head and 
said reaction support. 
7. An apparatus for making a weld around the circumfer- 
ence of a cylindrical object, as recited in claim 1, wherein 
25 said means for transmitting load from said weld head to said 
reaction support comprises an inflatable bladder reinforced 
with a metal band, said metal band is located between said 
weld head and said reaction support. 
8. An apparatus for making a weld around the circumfer- 
ence of a cylindrical object, as recited in claim 1, wherein 
said means for rotating said weld head in conjunction with 
said reaction support around the longitudinal axis of said 
cylindrical clamping mechanism comprises: 
a ring gear attached to said weld head and said reaction 
has a 
concentric with the cylindrical clamping mechanism (20); a 5 .  An apparatus for making a around the circumfer- 
said weld head and said reaction support; and 
with said weld head and said reaction support. 
" An apparatus for making a 
the work piece, depending on whether the preferred embodi- 35 support, said ring gear is concentric with said 
clamping mechanism; 
a drive gear engaged with said ring gear; and 
a motor for controlling rotation of said drive gear. 
9. An apparatus for making a weld around the circumfer- 
a base frame; 
a first cylindrical clamping mechanism attached to said 
base frame, said first cylindrical clamping means hav- 
a second cylindrical clamping mechanism attached to said 
base frame, said second cylindrical clamping means 
having a longitudinal axis coincident with the longitu- 
dinal axis of said first cylindrical clamping mechanism; 
a weld head rotationally mounted to said first and second 
cylindrical clamping mechanisms such that said weld 
head can be located at any position around the longi- 
tudinal axes of said clamping mechanisms; 
second cylindrical clamping mechanisms such that said 
reaction support is diametrically opposite said weld 
head; 
means for transmitting load from said weld head to said 
reaction support; and 
means for rotating said weld head in conjunction with said 
reaction support around the longitudinal axes of said 
first and second clamping mechanisms. 
10. An apparatus for making a weld around the &cum- 
a first cylindrical clamping mechanism, said first cylin- 
drical clamping means having a longitudinal axis; 
What is claimed is: 
1. An apparatus for making a weld around the circumfer- 
a base frame; 
a cylindrical clamping mechanism attached to said base 
frame, said cylindrical clamping means having a lon- 
gitudinal axis; 
a weld head rotationally mounted to said base frame such 
that said weld head can be located at any position 
around the longitudinal axis of said clamping mecha- 
nism; 
a reaction support rotationally mounted to said base frame 
45 ing a longitudinal axis; ence of a cylindrical object, comprising: 
such that said reaction support is diametrically opposite 55 a reaction support rotationally mounted to said first and 
said weld head; 
means for transmitting load from said weld head to said 
reaction support; and 
for rotating said weld head in conjunction with said 
reaction support around the longitudinal axis of said 60 
clamping mechanism. 
2. An apparatus for making a weld around the circumfer- 
ence of a cylindrical object, as recited in claim 1, wherein 
said cylindrical clamping mechanism has a first part and a 
second part spaced along the longitudinal axis of said 65 ference Of a 
cylindrical clamping mechanism such that said weld head 
and said reaction support are located between said two parts. 
Object, 
US 6,259,052 B1 
5 6 
a second cylindrical clamping mechanism, said second 
cylindrical clamping means having a longitudinal axis 
coincident with the longitudinal axis of said first cylin- 
drical clamping mechanism; 
a weld head rotationally mounted to said first and second 5 
cylindrical clamping mechanisms such that said weld 
head can be located at any position around the longi- 
tudinal axes of said clamping mechanisms; 
a reaction support rotationally mounted to said first and 
reaction support is diametrically opposite said weld 
head; 
means for transmitting load from said weld head to said 
reaction support; and 
means for rotating said weld head in conjunction with said 
reaction support around the longitudinal axes of said 
first and second clamping mechanisms. 
second cylindrical clamping mechanisms such that said * * * * *  


Orbital friction stir weld system

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