U.S. patent application number 10/854235 was filed with the patent office on 2005-12-01 for portable friction welder.
Invention is credited to Miller, Michael L..
Application Number | 20050263569 10/854235 |
Document ID | / |
Family ID | 35424080 |
Filed Date | 2005-12-01 |
United States Patent
Application |
20050263569 |
Kind Code |
A1 |
Miller, Michael L. |
December 1, 2005 |
Portable friction welder
Abstract
A portable friction welder that applies direct axial load to the
workpieces via a rotating variable pressure hydraulic cylinder
placed between the workpieces and a rotational device. The portable
friction welder includes an interchangeable adapter configured to
receive a fitting for a first workpiece, a variable pressure
hydraulic cylinder with a front end and a rear end, and a
rotational device positioned behind the rear end of the
pressurizing device. The friction welder is configured to be driven
by the rotational device, to be interconnected to a clamp assembly
holding a second workpiece, and to effect a friction weld to first
and second workpieces. The portable friction welder also includes a
bearing housing, thrusts bearings, and a thrust collar. Spring
washers may be installed in the front end of the hydraulic cylinder
to maintain axial load across the bearing housing. An
interchangeable adapter is removably connected with the thrust
collar.
Inventors: |
Miller, Michael L.;
(Kingwood, TX) |
Correspondence
Address: |
Richard C. Litman
LITMAN LAW OFFICES, LTD.
P.O. Box 15035
Arlington
VA
22215
US
|
Family ID: |
35424080 |
Appl. No.: |
10/854235 |
Filed: |
May 27, 2004 |
Current U.S.
Class: |
228/112.1 ;
228/2.1 |
Current CPC
Class: |
B23K 20/1285
20130101 |
Class at
Publication: |
228/112.1 ;
228/002.1 |
International
Class: |
B23K 020/12 |
Claims
1. A portable friction welder method comprising: providing a
portable friction welder with a rotating variable pressure
hydraulic cylinder; and applying direct axial load to workpieces
via the rotating variable pressure hydraulic cylinder.
2. The portable friction welder method according to claim 1,
further comprising: installing a clamp assembly including a thrust
collar and a shroud to a first workpiece; attaching an adapter to a
piston; inserting a fitting into the adapter; attaching a second
workpiece to the fitting; inserting a bearing housing into the
clamp assembly and locking the bearing housing into position;
pressurizing a pressuring device to a predetermined hydraulic
pressure; interconnecting a front end of the pressurizing device to
a rear end of the hydraulic cylinder; attaching a drive socket to a
rear end of the pressurizing device; inserting a rotational device
into the drive socket; running the rotational device for a
predetermined amount of time; removing the rotational device from
the drive socket and effecting a friction weld between the first
and second workpieces; maintaining hydraulic pressure on the
fitting for a predetermined amount of time; unlocking the bearing
housing from the clamp assembly; and removing the clamp assembly
from the welded first and second workpieces.
3. A portable friction welder configured to apply direct axial load
to workpieces via a rotating variable pressure hydraulic
cylinder.
4. The portable friction welder according to claim 3, further
comprising: a variable pressure hydraulic cylinder with a front end
and a rear end; and a rotational device positioned behind the rear
end of the pressurizing device.
5. The portable friction welder according to claim 4, wherein said
friction welder is configured to have a total length of about ten
inches when interconnected to the clamp assembly.
6. The portable friction welder according to claim 4, further
comprising a bearing housing, thrusts bearings, and a thrust
collar.
7. The portable friction welder according to claim 6, further
comprising spring washers installed in the front end of the
hydraulic cylinder to maintain axial load across the bearing
housing.
8. The portable friction welder according to claim 7, further
wherein said spring washers are Belleville washers.
9. The portable friction welder according to claim 4, further
comprising an interchangeable adapter configured to receive a
fitting for a first workpiece, wherein the friction welder is
configured to be driven by the rotational device, to be
interconnected to a clamp assembly holding a second workpiece, and
to effect a friction weld to first and second workpieces.
10. The portable friction welder according to claim 4, wherein said
hydraulic cylinder is configured to provide an axial load from zero
tons to about one hundred tons.
11. The portable friction welder according to claim 4, further
wherein said hydraulic cylinder is configured to be pressurized
hydraulically with a pump, through the use of an accumulator,
and/or manually by turning or squeezing a nut.
12. The portable friction welder according to claim 4, further
comprising a pressurizing device configured to pressurize the
hydraulic cylinder.
13. The portable friction welder according to claim 12, wherein
said pressurizing device is an accumulator.
14. The portable friction welder according to claim 13, wherein
said accumulator is selected from the group consisting of selected
from the group consisting of a diaphragm, bladder-type,
piston-type, and bellow-type accumulator.
15. The portable friction welder according to claim 4, further
comprising an interchangeable drive socket configured to receive
the rotational device.
16. The portable friction welder according to claim 15, wherein
said rotational device is an air motor.
17. The portable friction welder according to claim 15, wherein
said rotational device is an electric motor.
18. The portable friction welder according to claim 4, further
comprising a clamp assembly.
19. The portable friction welder according to claim 18, wherein
said clamp assembly includes a clamp and a shroud.
20. The portable friction welder according to claim 19, wherein
said shroud includes a purge stem.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to friction welding
and, more particularly, to a portable friction welder for welding
first and second workpieces together that applies direct axial load
to the workpieces via a rotating variable pressure hydraulic
cylinder placed between the workpieces and a rotational device.
[0003] 2. Description of the Related Art
[0004] Friction welding is a process that welds metal or
thermoplastics in which two members are joined by rubbing the mated
parts under pressure. Heat is generated by direct conversion of
mechanical energy to thermal energy at the interface of the mated
parts, without application of electrical energy or heat from other
sources. The weld is made by holding a non-rotating part in contact
with a rotating one under constant or gradually decreasing
pressure, until the interface reaches a certain temperature, e.g.,
forging temperature for metal parts. Rotation is then automatically
stopped for a short period of time to consolidate the weld. Weld
time varies depending on the materials being joined and the stud
diameter. In systems directing the flow of fluids or gases, valves
which control the flow of fluids and gases often need to be
replaced, repaired, or repacked. Typically, the drill and tap
technique is used to join workpieces in the valve repair industry.
A drill initially bores a hole into a second workpiece and the
bored hole is tapped or threaded. A threaded first workpiece, e.g.
a fitting, is then able to be joined to the second workpiece.
Constraints in the choice of workpieces that may be joined, the
need to have a threaded first workpiece to join to the bored and
tapped second workpiece, extreme care needed to assure the initial
drill step does not penetrate too far and go into the pressure or
hazardous area and cause a safety and environmental issue, and
sufficient remaining wall thickness after drilling and prior to
tapping,. proper thread sealing are some problems associated with
the drill and tap technique.
[0005] Prior friction weld techniques used to join workpieces by
friction welding use an actuator located between the workpiece and
motor surrounding the workpiece. This provides an indirect force on
the workpiece. Through the workpiece-actuator-motor mechanism, the
first workpiece is rotated and then placed in contact with a second
workpiece. The combination of rotational drive, and indirect axial
force causes the first workpiece to weld to the second workpiece.
This indirect friction welding technique improves upon the
weaknesses of the drill and tap technique by decreasing gas or
fluid leaks by reducing the number of possible leak points present
in tap junctions, reducing the risk of creating sparks, reducing
the risk of drilling through the second workpiece, and offering a
wider selection in workpieces which may be joined.
[0006] However, friction welding has not been successfully
implemented due, in part, to two major weaknesses. First, the
indirect means of applying force with the indirect
workpiece-actuator-motor configuration does not supply the
necessary amount of force to provide a sufficiently strong weld,
particularly when dealing with curved surfaces. Second, the portion
of the second workpiece in contact with flammable materials may
reach high surface temperatures resulting in ignition of the
flammable materials. Arc welding is currently used to perform welds
on site. However, arc welding is not performed on small fittings
(e.g., two inches and lower) because arc welding occurs at
temperatures significantly higher than friction welding, and
degrades small fittings or base metals due to heat concentration on
the small fittings. Friction welding is currently performed with
stationary friction welders that are large and are unable to be
utilized on live systems. Normally, friction welding work is
delivered to a location where a stationary friction welder is
present.
[0007] A portable friction welder applying direct axial load to the
workpieces via a rotating variable pressure hydraulic cylinder
placed between the workpieces and a rotational device would be an
improvement over the current arc welders and stationary friction
welders because such a portable friction welder would enable a user
to carry the portable friction welder on site and operate on live
systems, and the motor would be totally independent of the
pressurizing device. Such a portable friction welder would be able
to effectively weld fittings of two inches and lower because they
would operate at significantly lower temperatures than arc welders,
and would not , degrade small fittings or base metals because the
low temperatures would allow heat to be displaced. A portable
friction welder would also allow welded work to be contained and
purged.
[0008] Therefore, a need exists for a portable friction welder
which welds workpieces together with sufficient force to provide
sufficient weld strengths, minimizes fluid or gas leaks, reduces
the surface temperature of the workpiece portion in contact with
flammable materials, and provides a simple and effective means to
accomplish these goals using a variety of workpiece materials,
shapes, and configurations.
[0009] The related art is represented by the following references
of interest.
[0010] U.S. Patent Application Publication No. 2001/0015369 A1,
published Aug. 23, 2001 for Edward Litwinski et al., describes a
back-up tolling apparatus for supporting the inner side of a hollow
cylindrical workpiece during a circumferential friction stir weld
that includes a plurality of arcuate shoes configured to mate
end-to-end to form a substantially continuous ring, and an
expandable support for supporting the shoes and operable to retract
and expand the shoes inward and outward. The Litwinski et al.
application does not suggest a portable friction welder according
to the claimed invention.
[0011] U.S. Pat. No. 3,599,857, issued Aug. 17, 1971 to Calvin D.
Lloyd, describes a friction welding machine that is adapted to weld
workpieces having a wide range of diameters by utilizing a
unidirectional drive means which is disposed between rotatable
components of the machine and a rotatable workpiece holding
spindle. The Lloyd patent does not suggest a portable friction
welder according to the claimed invention.
[0012] U.S. Pat. No. 3,616,980, issued Nov. 2, 1971 to John A.
Padilla, describes a friction welding apparatus having a rotatable
chuck for holding a first workpiece which in operation is caused to
rotate and is brought into contact with a second workpiece, during
which rotation and axial force is applied to the first workpiece,
thereby welding the first workpiece to the second workpiece. The
Padilla patent does not suggest a portable friction welder
according to the claimed invention.
[0013] U.S. Pat. No. 3,775,834, issued Dec. 4, 1973 to Yuji
Ishikawa et al., describes a method and apparatus for friction
welding in which two bodies to be welded together are brought into
relative rotation and are also pressed against each other to
achieve the welding by making use of the friction heat generated at
their contact points. The Ishikawa et al. patent does not suggest a
portable friction welder according to the claimed invention.
[0014] U.S. Pat. No. 3,840,979, issued Oct. 15, 1974 to Robert G.
Miller et al., describes a friction welding process and a friction
welding machine of the kind in which two parts are engaged in
rotating contact under contact under an axial load at a common
interface to heat the interface to a hot plastic condition. The
Miller et al. patent does not suggest a portable friction welder
according to the claimed invention.
[0015] U.S. Pat. No. 4,122,990, issued Oct. 31, 1978 to Yoshio
Tasaki et al., describes a portable friction welding device which
enables metallic parts to be easily united by frictional welding
onto structures. The Tasaki et al. patent does not suggest a
portable friction welder according to the claimed invention.
[0016] U.S. Pat. No. 4,593,848, issued Jun. 10, 1986 to David E.
Hochbein, describes a portable apparatus for friction joining metal
pieces to an electrical conductor while the conductor is carrying
electrical current. The Hochbein patent does not suggest a portable
friction welder according to the claimed invention.
[0017] U.S. Pat. No. 4,735,353, issued Apr. 5, 1998 to Allan R.
Thomson et al., describes a method and apparatus for friction
welding. The Thomson et al. patent does not suggest a portable
friction welder according to the claimed invention.
[0018] U.S. Pat. No. 4,811,887, issued Mar. 14, 1989 to Clive G.
King et al., describes a method and apparatus for friction welding
a pair of workpieces. The King et al. '887 patent does not suggest
a portable friction welder according to the claimed invention.
[0019] U.S. Pat. No. 5,148,957, issued Sep. 22, 1992 to John G.
Searle, describes an apparatus for use in welding two workpieces
together. The Searle patent does not suggest a portable friction
welder according to the claimed invention.
[0020] U.S. Pat. No. 5,261,592, issued Nov. 16, 1993 to Vinci M.
Felix et al., describes a process for friction welding
molybdenum-rhenium alloys that include from about 10% to about 50%
by weight. The Felix et al. patent does not suggest a portable
friction welder according to the claimed invention.
[0021] U.S. Pat. No. 5,699,952, issued Dec. 23, 1997 to John W.
Fix, Jr., describes a lightweight, portable automated fusion
bonding apparatus. The Fix, Jr. '952 patent does not suggest a
portable friction welder according to the claimed invention.
[0022] U.S. Pat. No. 5,735,447, issued Apr. 7, 1998 to John W. Fix,
Jr., describes a friction welding apparatus and a method for its
use where the apparatus includes a plurality of interchangeable
components including a drive means, an actuator assembly, a support
system, and a control system, the combination operable to friction
weld a workpiece to a valve body. The Fix, Jr. '447 patent does not
suggest a portable friction welder according to the claimed
invention.
[0023] U.S. Pat. No. 5,785,805, issued Jul. 28, 1998 to John W.
Fix, Jr., describes a friction welding fusion enhancer apparatus.
The Fix, Jr. '805 patent does not suggest a portable friction
welder according to the claimed invention.
[0024] U.S. Pat. No. 6,021,938, issued Feb. 8, 2000 to Johann Bock
et al., describes a process and device for the friction welding of
workpieces that consist of different materials or posess different
material properties. The Bock et al. patent does not suggest a
portable friction welder according to the claimed invention.
[0025] U.S. Pat. No. 6,095,395, issued Aug. 1, 2000 to John W. Fix,
Jr., describes a friction. welder drill and fuse fitting apparatus.
The Fix, Jr. '395 patent does not suggest a portable friction
welder according to the claimed invention.
[0026] U.S. Pat. No. 6,554,175 B1, issued Apr. 29, 2003 to Jack M.
Thompson, describes a friction stir welding machine that includes a
table for supporting parts to be welded and a frame extending over
the table. The Thompson patent does not suggest a portable friction
welder according to the claimed invention.
[0027] U.S. Pat. No. 6,634,540 B1, issued Oct. 21, 2003 to Paul
Afschrift et al., describes a method for welding the far ends of
two elongated elements together, whereby the above-mentioned far
ends are heated up to forging temperature by rotating a ring
clamped between them. The Afschrift et al. patent does not suggest
a portable friction welder according to the claimed invention.
[0028] U.S. Pat. No. 6,691,910 B2, issued Feb. 17, 2004 to Masahito
Hirose et al., describes a rod material made of Ti alloy that has a
larger diameter portion at the end, which is joined with the end of
material made of Ti--Al intermetallic compound, by friction
welding, to form a poppet valve for an internal combustion engine.
The Hirose et al. patent does not suggest a portable friction
welder according to the claimed invention.
[0029] U.S. Pat. No. 6,703,093 B2, issued Mar. 9, 2004 to Derek J.
Foster, describes a friction welded component and a method of
manufacture for such a component. The Foster patent does not
suggest a portable friction welder according to the claimed
invention.
[0030] Japan Patent Application Publication No. 58-20388, published
on Feb. 5, 1983, describes a friction welding machine which adapts
itself to press welding of long-sized materials by providing a
rotary unit which holds an intermediate material between two
clamping units for gripping pipes, rotating only the intermediate
material and drawing the units on both sides toward each other. The
Japan '388 application does not suggest a portable friction welder
according to the claimed invention.
[0031] Japan Patent Application Publication No. 58-38686, published
on Mar. 7, 1983, describes a portable friction welding machine. The
Japan '686 application does not suggest a portable friction welder
according to the claimed invention.
[0032] World Intellectual Property Organization (WIPO) Patent
Application Publication No. WO 97/48518, published on Dec. 24,
1997, describes a portable friction welding apparatus and method.
The WIPO '518 application does not suggest a portable friction
welder according to the claimed invention.
[0033] None of the above inventions and patents, taken either
singly or in combination, is seen to describe the instant invention
as claimed. Thus a portable friction welder solving the
aforementioned problems is desired.
SUMMARY OF THE INVENTION
[0034] The present invention is a portable friction welder for
friction welding workpieces together that applies direct axial load
to the workpieces via a rotating variable pressure hydraulic
cylinder placed between the workpieces and a rotational device. The
portable friction welder includes an interchangeable adapter
configured to receive a fitting for a first workpiece, a variable
pressure hydraulic cylinder with a front end and a rear end, and a
rotational device positioned behind the rear end of the
pressurizing device. The friction welder is configured to be driven
by the rotational device, to be interconnected to a clamp assembly
holding a second workpiece, and to effect a friction weld to first
and second workpieces.
[0035] The portable friction welder also includes a bearing
housing, thrusts bearings, and a thrust collar. Spring washers may
be installed in the front end of the hydraulic cylinder to maintain
axial load across the bearing housing. An interchangeable adapter
is configured to engage a fitting, and the adapter is removably
connectable with the thrust collar. The hydraulic cylinder is
configured to be pressurized hydraulically with a pump, through the
use of an accumulator, an/or manually by turning or squeezing a
nut.
[0036] The portable friction welder may include a pressurizing
device configured to pressurize the hydraulic cylinder. The
pressurizing device may be an accumulator selected from the group
consisting of selected from the group consisting of a diaphragm,
bladder-type, piston-type, and bellow-type accumulator.
[0037] The portable friction welder also includes an
interchangeable drive socket configured to receive a rotational
device, such as an air motor, an electric motor, etc. The portable
friction welder also includes a clamp assembly including a clamp
and a shroud. The shroud includes a purge stem and the clamp
includes a seat to stabilize the friction welder.
[0038] Accordingly, it is a principal aspect of the invention to
provide a portable friction welder and method for friction welding
workpieces together that applies direct axial load to the
workpieces via a rotating variable pressure hydraulic cylinder
placed between the workpieces and a rotational device.
[0039] It is another aspect of the invention to provide a portable
friction welder including an interchangeable adapter configured to
receive a fitting for a first workpiece, a variable pressure
hydraulic cylinder with a front end and a rear end, and a
rotational device position behind the rear end of the pressurizing
device. The friction welder is configured to be driven by the
rotational device, to be interconnected to a clamp assembly holding
a second workpiece, and to effect a friction weld to first and
second workpieces.
[0040] It is a further aspect of the invention to provide a
portable friction welder method including the steps of installing a
clamp assembly including a thrust collar and a shroud to a first
workpiece, attaching an adapter to the thrust collar, inserting a
fitting into the adapter, attaching a second workpiece to the
fitting, inserting a bearing housing into the clamp assembly and
locking the bearing housing into position, pressurizing a
pressuring device to a predetermined hydraulic pressure,
interconnecting a front end of the pressurizing device to a rear
end of the hydraulic cylinder, attaching a drive socket to a rear
end of the pressurizing device, inserting a rotational device into
the drive socket, running the rotational device for a predetermined
amount of time, removing the rotational device from the drive
socket and effecting a friction weld between the first and second
workpieces, maintaining hydraulic pressure on the fitting for a
predetermined amount of time, unlocking the bearing housing from
the clamp assembly, and removing the clamp assembly from the welded
first and second workpieces.
[0041] It is an aspect of the invention to provide improved
elements and arrangements thereof in a portable friction welder for
the purposes described which is inexpensive, dependable and fully
effective in accomplishing its intended purposes.
[0042] These and other aspects of the present invention will become
readily apparent upon further review of the following specification
and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0043] The sole figure is a top view of a portable friction welder
according to the present invention.
[0044] FIG. 1 is a side view of a portable friction welder
according to the present invention.
[0045] FIG. 2 is a side perspective view of a clamp for use with a
portable friction welder according to the present invention.
[0046] FIG. 3 is a block diagram of a portable friction welder
according to the present invention.
[0047] Similar reference characters denote corresponding features
consistently throughout the attached drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0048] The present invention is a portable friction welder for
friction welding workpieces together that applies direct axial load
to the workpieces via a rotating variable pressure hydraulic
cylinder placed between the workpieces and a rotating device. The
invention disclosed herein is, of course, susceptible of embodiment
in many different forms. Shown in the drawings and described herein
below in detail are preferred embodiments of the invention. It is
to be understood, however, that the present disclosure is an
exemplification of the principles of the invention and does not
limit the invention to the illustrated embodiments.
[0049] Referring to the drawings, FIG. 1 shows a portable friction
welder 10 according to the present invention that applies direct
axial load to the workpieces via a rotating variable pressure
hydraulic cylinder 12 placed between the workpieces and a
rotational device 50. The friction welder 10 includes a rotatable
variable pressure hydraulic cylinder 12, a bearing housing 22,
thrusts bearings 24, a thrust collar 26, guide pins 28, an
interchangeable adapter 30, a fitting 32, an optional pressurizing
device 40, and an interchangeable drive socket 44.
[0050] The friction welder 10 is configured to be driven by an
interchangeable rotational device 50, and is configured to be
interconnected to a clamp assembly 60 to effect the friction weld
to workpieces (not shown). When interconnected to the clamp
assembly 60 the friction welder 10 preferably has an approximate
total length of about ten inches, which total length may be varied
as desired. The inventor believes that the particular configuration
of the portable friction welder is novel because the inventor is
unaware of any friction welder that positions a rotating variable
pressure hydraulic cylinder 12 configured to apply a direct axial
load to the workpieces between the workpieces and the rotational
device 50, increases versatility, reduces overall length, and
optimizes the ability to provide unlimited direct axial load to
workpieces on the basis of rotation (revolutions per minute) of the
rotational device and time.
[0051] The variable pressure hydraulic cylinder 12 includes a
cylinder with a predetermined diameter, a front end, and a rear
end. The front end of the hydraulic cylinder 12 is attached to the
rear surface of the bearing housing 22. Spring washers, such as
Belleville washers, may be installed in the front end of the
hydraulic cylinder 12 to maintain axial load across the bearing
housing 22. The rear end of the hydraulic cylinder 12 includes a
fluid port and is connected to the optional pressurizing device 40.
The hydraulic cylinder 12 is configured to be pressurized by the
pressurizing device 40 and to exert a direct axial load to the
adapter 30 and fitting 32. The axial load capability of the
hydraulic cylinder 12 may range from zero tons to about one hundred
tons.
[0052] The bearing housing 22 includes front and rear surfaces.
thrust bearings 24 and a thrust collar 26 are centrally mounted in
the bearing housing 22. The thrust collar 26 annularly extends from
the front surface of the bearing housing 22. The thrust collar 26
is configured to interchangeably receive various types of adapters
30, and is configured to take direct axial thrust loads from the
hydraulic cylinder 12. The rear surface of the bearing housing 22
is interconnected with the front end of the hydraulic cylinder 12.
The bearing housing 22 is configured to be inserted into the clamp
assembly utilizing the guide pins 28 and it is then locked into
position.
[0053] The interchangeable adapter 30 includes a socket at one end
that may be configured to engage a hex fitting, a square fitting,
etc. The other end of the adapter is removably connected with the
thrust collar 26 so that adapters configured for various fittings
may be removably connected to the thrust collar 26. The adapter 30
is preferably formed of metal, such as iron or steel, and has no
sharp edges on its exterior surface. The fitting 32 is a threaded
fitting preferably configured for holding a one-quarter inch to
about a two inch workpiece, but this dimensional range may vary as
desired.
[0054] The optional pressuring device 40 has a front end and a rear
end, and is illustrated as a gas charged bladder-type diaphragm
accumulator. The accumulator 40 has a sealed housing with a valve,
such as a Schroeder valve or the like, to enable the accumulator to
be pressurized to a desired pressure. Positioned within the housing
is a sheet-like movable diaphragm composed of a flexible material,
such as rubber, to subdivide the interior space into two
fluid-tight pressure chambers on opposite sides of the diaphragm.
One chamber is a fluid chamber into and out of which the working
hydraulic fluid of the friction welder 10 is accumulated and
expelled under pressure when required. The other chamber is charged
with an inert gas, such as argon, nitrogen, xenon, krypton, etc.,
under high pressure to act as an energy storage medium. In use, the
working fluid accumulates in the fluid chamber and when the fluid
pressure exceeds the pressure of the trapped gas, the diaphragm is
elastically displaced, further compressing the gas on the other
side. The gas is later utilized to expel on demand the stored fluid
under pressure out of the fluid chamber back into the hydraulic
cylinder 12.
[0055] Other types of gas charged accumulators may also be used
including piston-type and bellow-type accumulators. While the
friction welder 10 is illustrated with one type of pressurizing
device 26 configured to pressurize the hydraulic cylinder 12, it is
to be understood that the hydraulic cylinder 12 may be pressurized
in any one of a number of ways including hydraulically with a pump,
through the use of an accumulator, and/or manually by turning or
squeezing a nut, thereby precluding the need for a pressurizing
device.
[0056] The interchangeable drive socket 28 is configured to
interchangeably receive various types of rotational devices 30,
such as air motors, electric motors, etc. The drive socket 28 may
be configured as a hex socket, a square socket, etc.
[0057] The clamping assembly 60 includes a clamp 62 and a shroud
70. The shroud 70 includes a purge stem 72. The clamp 62 may be
adjustably configured for clamping to plates having a diameter
ranging from about one to fifty inches. The clamp 62 includes a
seat 64 to stabilize the welder 10 (see FIG. 2). The seat 64
terminates and transcends into the shroud 70. The shroud 70
functions as a purge chamber around a workpiece by directing inert
gas to the region of the weld when forming the friction weld.
[0058] The portable friction welder 10 is configured to be carried
by a human operator for friction welding two workpieces to each
other. The operation of the portable friction welder 10 is effected
by installing the clamp assembly 60 to a first workpiece, e.g. a
pipe, a plate, a flange, etc. An appropriately configured adapter
30 is then attached to the thrust collar 26. An appropriately
configured fitting 32 is then inserted into the adapter 30.
[0059] A second workpiece is attached to the fitting 32. The guide
pins 28 of the bearing housing 22 are then inserted into the
openings 66 in the clamp 60 and the bearing housing 22 is locked
into position. The pressurizing device 26 is then pressurized to an
appropriate axial load. The front end of the pressurizing device 26
is then interconnected to the rear end of the hydraulic cylinder
12. An appropriate drive socket 44 is then attached to the rear end
of the pressurizing device 40.
[0060] An appropriate rotational device 50 is then inserted into
the drive socket 44. The rotational device 50 may be inserted to
the drive socket 44 at any angle from in-line (e.g., zero degrees)
to ninety degrees. The rotational device 50 is then run for a
predetermined amount of time. The portable friction welder 12 may
be configured with automatic start and stop elements. The
rotational device 50 is then removed from the drive socket 44 and a
friction weld is effected between the first and second workpieces.
Hydraulic pressure is maintained on the fitting 32 for a
predetermined amount of time, such as one minute, after rotation
ceases. The bearing housing 24 is then unlocked from the clamp
assembly and the clamp assembly is then removed from the welded
first and second workpieces.
[0061] The portable friction welder 10 produces welds with a joint
strength equal to or stronger than the parent materials, at a lower
cost per weld than conventional welding devices. The weld
preparation is less costly than conventional welds and the weld
joints are very reliable. In addition, dissimilar materials can be
welded without filler material. The friction weld also provides
self-cleaning/decontamination of the weld interface.
[0062] The portable friction welder 10 according to the invention
that applies direct axial load to the workpieces via a rotating
variable pressure hydraulic cylinder placed between the workpieces
and a rotational device. The portable friction welder 10 applies a
direct axial load to the workpieces between the workpieces and the
rotational device 50, increases versatility, reduces overall
length, and optimizes the ability to provide unlimited direct axial
load to workpieces on the basis of rotation (revolutions per
minute) of the rotational device and time. The portable friction
welder 10 applies direct rotation to the portable variable pressure
hydraulic cylinder 12 which provides the capability of friction
welding various size fittings to a base metal or substrate
utilizing various driving devices, thereby increasing versatility
and capability over known friction welders.
[0063] While the invention has been described with references to
its preferred embodiment, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the true
spirit and scope of the invention. In addition, many modifications
may be made to adapt a particular situation or material to the
teaching of the invention without departing from its essential
teachings.
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