Note: Descriptions are shown in the official language in which they were submitted.
~L2~
ARC WELDING SYSTEM AND
DOCKING ASSEMBLY THE~EFOR
Reference to Related Application
The present invention is an improvement of the
invention disclosed and claimed in my United States
Patent No. 4,600,824, entitled "ARC WELDING SYSTEM
AND DOCKING ASSEMBLY THEREFOR". The docking assembly
of that application may be used interchangeably with
the present invention in the same system.
Background of the Invention
The present invention relates to welding apparatus
and systems, particularly Metal Inert Gas ("MIG")
arc welding systems. The invention relates
particularly to arc welding systems of the type
utilized in mechanized and robotic welding.
Typically, a MIG welding system includes a
welding gun or torch assembly which feeds a consumable
wire electrode through a current pick-up tip which
applies welding potential to the electrode. Such
welding gun assemblies may, for example, be of the
types disclosed in my U.S. Patents Nos. 3,496,328
and 3,775,584. The gun assembly includes a main
body or housing to which is removably mounted a
welding nozzle which surrounds the welding tip and
channels an inert shielding gas to the welding arc.
The nozzle may be air or water cooled. The welding
gun assembly must be serviced with the utilities
which it requires for operation, such as water
for nozzle cooling, gas for shielding the welding
6~
~ arc and electricity to effect the welding, as well as
; being provided with the consumable wire electrode. All
of these utilities are fed to the welding gun assembly
from associated supplies via utilities delivery means,
which may include a portable utilities station of the
type disclosed in my U.S. Patent No. 4,210,796.
When the welding system is to be utilized in mech-
anized or automated applications, the welding gun assem-
bly is fixedly mounted on the automated welding control
equipment. For example, the welding gun assembly may
be mounted on a permanent fixed mount to which work-
pieces are delivered for welding or, alternatively,
might be mounted on a movable mount such as that of a
robotic welding machine, which moves to the workpiece
under remote control, and which may be pre-programmed.
;~
; In such prior welding systems, the replacement of
~¦ the welding gun assembly or parts thereof is extremely
inconvenient, particularly in the automated or robotic
applications. Thus, for example, in the event of sys-
~ 20 tem malfunction or damage to the welding gun assembly,
it is necessary to replace the complete assembly, in-
; cluding all the utilities delivery means all the way
back to the wire drive system. This is a very costly
i procedure, not only because it is time consuming, but
also because it may, particularly in factory applica-
tions, require the involvement of several different
~` tradesmen, such as electricians, plumbers, welders and
the like.
Furthermore, in robotic welding applications, the
replaced welding gun assembly will not be in precisely
-2-
.
~2S6~. 7 -
the same location and orientation with respect to the
robot unit as was the original gun assembly. Since
this precise positioning is critical to maintenance of
a pre-programmed welding path, the system must be
recalibrated at the cost of additional time and labor.
The aforementioned U.S. Patent No. 4,600,824
discloses a docking assembly for a welding system,
which permits the welding gun or torch assembly to be
easily manually replaced at the welding station,
without affecting the utilities delivery means
upstream of the welding station, and without losing
the precise positioning of the gun assembly in the
system.
However, there are many occasions when only the
nozzle assembly needs to be replaced, and not the
entire gun assembly. For example, in normal operation
the nozzle assembly may become clogged or fouled with
spattering from the welding operation, thereby impeding
the flow of shielding gas through the nozzle assembly
to the welding arc. In such instances, it is necessary
to shut down the welding operation to either clean the
nozzle assembly in place, or replace it with a new
nozzle assembly. While the nozzle assemblies of prior
art welding guns, including the nozzle assemblies
disclosed in the aforementioned copending Patent No.
4,600,824, can be removed, this cannot be done easily,
I particularly in the case of water-cooled nozzles.
Thus, water cooled nozzles are provided with water
conduits which are coupled to the rest of the gun
assembly by threaded fittings which must be
disconnected with the use of a wrench or other suitable
tool.
- ~z56~67
Furthermore, the supply of cooling water must be shut
down at the source during such nozzle replacement to
avoid extensive water spillage at the welding station.
Such spillage can be extremely troublesome, particular-
ly in the case of aluminum welding, since water is a
source of hydrogen which seriously impairs the forma-
tion of porosity-free weldments in aluminum.
Summary of the Invention
It is a general object of the present invention to
provide an improved welding system which avoids the dis-
advantages of prior systems while affording additional
structural and operating advantages.
An important object of the invention is the provi-
sion of a docking assembly which permits a water cooled
welding nozzle assembly to be mounted and demounted at
a welding station, without affecting the utilities de-
livery means upstream of the welding station.
In connection with the foregoing object, it is an-
other object of this invention to provide a docking as-
sembly of the type set forth which permits the use of anumber of manually interchangeable welding nozzle
assemblies.
Still another object of the invention is the provi-
sion of a docking assembly which permits ready mounting
and demounting of a water-cooled welding nozzle assem-
bly at the welding station without spillage of cooling
fluid.
In connection with the foregoing objects, another
object of the invention is the provision of a docking
assembly of the type set forth, which can be substitut-
-4-
~:256~
ed for other docking assemblies without loss of accu-
rate positioning of the nozzle assembly in the system.
Yet another object of the invention is the provi-
sion of a docking body for use in a docking assembly of
the type set forth.
These and other objects of the invention are at-
tained by providing a docking assembly for an arc weld-
ing system including a tip assembly for guiding a wire
electrode to an associated workpiece at a welding sta-
tion and applying welding voltage to the electrode, a
fluid-cooled nozzle assembly surrounding the tip assem-
bly for channeling a shielding gas to the welding arc,
and utilities delivery means for delivering to the weld-
ing station utilities such as welding voltage, arc
shielding gas, consumable wire electrode and cooling
fluid, the docking assembly comprising: a docking body
disposed at the welding station and having utilities
passages therethrough, means connecting the docking
body to the associated utilities delivery means and re-
ceiving the wire electrode and the fluid utilities into
the passages, an output fixture carried by the docking
body and communicating with selected ones of the pas-
sages for passing consumable wire electrode and shield-
ing gas from the docking body, means on the output
fixture for removably mounting the tip assembly thereon
in a use configuration receiving the wire electrode
into the tip assembly, first coupling means on the
docking body, and second coupling means on the nozzle
assembly, the first and second coupling means being
manually removably engageable with each other without
6i
the use of tools for mounting the nozzle assembly on
the docking body in a mounted condition in surrounding
relationship with the tip assembly for receiving the
shielding gas and the cooling fluid, whereby the nozzle
assembly can readily be mounted and demounted at the
welding station without affecting the utilities de-
~ livery means upstream of the welding station.
; The invention consists of certain novel features
; and a combination of parts hereinafter fully described,
illustrated in the accompanying drawings, and partic-
ularly pointed out in the appended claims, it being un-
derstood that various changes in the details may be
made without departing from the spirit, or sacrificing
any of the advantages of the present invention.
Brief Description of the DrawinRs
For the purpose of facilitating an understanding of the
invention, there are illustrated in the accompanying
drawings preferred embodiments thereof, from an inspec-
tion of which, when considered in connection with the
following description, the invention, its construction
and operation, and many of its advantages should be
readily understood and appreciated.
FIG. 1 is a fragmentary side elevational view of a
welding system including a welding unit incorporating a
docking assembly constructed in accordance with and em-
bodying the features of a first embodiment of the pres-
ent invention;
FIG. 2 is a side elevational view of a welding sys-
tem incorporating a docking assembly in accordance with
a second embodiment of the present invention;
--6--
s6~
FIG. 3 is an enlarged, fragmentary, partially ex-
ploded side elevational view of the docking assembly
and associated welding unit of FIG. l;
FIG. 4 is a further enlarged, fragmentary, side el-
evational view of the docking body of the docking as-
sembly of FIG. 3, rotated 90 counterclockwise;
FIG. 5 is an end elevational view of the docking
body of FIG. 4, as viewed from the right-hand end
thereof;
FIG. 6 is an end elevational view of the docking
body of FIG. 4, as viewed from the left-hand end
thereof;
FIG. 7 is a view in vertical section taken along
the line 7-7 in FIG. 5;
FIG. 8 is a view in horizontal section, taken
~ along the line 8-8 in FIG. 4, and including the tip as-
i sembly of the associated welding unit;
FIG. 9 is a view similar to FIG. 4, in partial ver-
tical section, illustrating the nozzle assembly docked
with the docking body;
FIG. 10 is a further enlarged, fragmentary view in
vertical section of the nozzle assembly of the welding
unit of FIG. 3, rotated 90 clockwise;
FIG. 11 is a still further enlarged, fragmentary
sectional view of a portion of the nozzle assembly of
FIG. 10 adjacent to the distal end thereof;
FIG. 12 is a further enlarged, fragmentary section-
al view of a portion of the nozzle assembly of FIG. 10
adjacent to the coupled end thereof;
2561~'7
FIG. 13 is a further enlarged view in vertical sec-
tion taken along the line 13-13 in FIG. 10;
FIG. 14 is a further enlarged view in vertical sec-
tion taken along the line 14-14 in FIG. 10;
FIG. 15 is an enlarged top plan view of the dock-
ing assembly of FIG. 2, taken generally along the line
15-15 in FIG. 2;
FIG. 16 is a further enlarged bottom plan view of
the docking spool of FIG. 15, rotated 180;
FIG. 17 is a view in vertical section, taken along
the line 17-17 in FIG. 16, and rotated 90
counterclockwise;
FIG. 18 is a view in vertical section taken along
the line 18-18 in FIG. 16, rotated 90 counterclock-
wise and including the tip assembly of the associated
welding unit;
FIG. 19 is a view in vertical section taken along
the 19-19 in FIG. 16, rotated 90 counterclockwise and
~ including the wire guide of the associated welding
; 20 unit;
; FIG. 20 is enlarged view in vertical section, ro-
tated 90 counterclockwise, of the nozzle assembly of
the welding unit of FIG. 2;
FIG. 21 is a further enlarged view in vertical sec-
tion taken along the line 21-21 in FIG. 20;
FIG. 22 is an enlarged side elevational view of
the gas diffuser ring of the nozzle assembly of FIG.
20;
FIG. 23 is a view in vertical section taken along
the line 23-23 in FIG. 22;
~256167
FIG. 24 is a view in vertical section taken along
the line 24-24 in FIG. 22; and
FIG. 25 is a fragmentary sectional view of a
modified tip assembly of the present invention.
Description of the Preferred Embodiments
Referring to FIG. 1 there is illustrated an arc
welding system, generally designated by the numeral 50,
of the type for use in robotic welding applications.
More specifically, an associated robot machine (not
shown) of known construction has a robot arm 51
provided with an articulated wrist 52 at the distal end
thereof, which carries a gun mounting bracket 53.
Mounted in the gun mounting bracket 53 is an arc
welding unit 55 for performing welding operations at a
welding station 56. Typically, the robot arm 51 and
wrist 52 will move, under computer program control, as
necessary to cause the welding unit 55 to follow a
predetermined weld path along an associated workpiece
(not shown). The welding unit 55 includes a docking
body 100 to which is releasably coupled a water-cooled
nozzle assembly 160, all in accordance with a first
embodiment of the present invention, as will be
explained in greater detail below.
The utilities may be supplied to the welding unit
55 by a movable utilities station 60, which may be of
the type disclosed in my U.S. Patent No. 4,210,796.
Typically, the utilities station 60 is supported
overhead on a boom or other structure carrying a
manifold system which may supply a plurality of such
.1
1:256~6~7
utilities stations 60, one for each of a number of
robot machines. Associated with the utilities station
60 is a wire feeder 61 which feeds a consumable wire
electrode M from an associated supply into a wire guide
in the utilities station 60. Also supplied to the
utilities station 60 are cooling water W via a conduit
62 and arc shielding gas G via a conduit 63, the
recirculated cooling water being returned to a suitable
drain D via a conduit 64. Electric welding potential E
is applied to the utilities station 60 through a power
cable 65. The utilities are then delivered from the
utilities station 60 to the welding unit 55 via a
number of conduits encased in a delivery conduit sheath
70. Specifically, the sheath 70 encloses a wire
electrode casing 71, a water inlet hose 72, a water
drain hose 73 in which is embedded a power cable, and a
gas inlet hose 74. The sheath 70 and the associated
conduits all have a length sufficient to accommodate
the programmed movement of the welding unit 55.
Referring to FIG. 2, there is illustrated an alter-
native version of the present invention, designed for
use with fixed or dedicated mechanized welding applica-
tions. More specifically, in this version a fixed
mounting plate 80 on a robot or other welding machine
carries a wire feeder 81 of known construction which
supplies the metal wire electrode M from an associated
supply reel 82 which is also fixedly mounted on the
plate 80. Also carried by the plate 80 is a welding
unit 85 which includes a wire guide 86 for receiving
and guiding the wire electrode M from the wire feeder
- 1 O-
~256~67
81 to an associated docking body ~00, on which is
mounted a nozzle assembly 260. Communication between
the docking body 200 and the associated utilities
supply and the water drain is provided by a water inlet
hose 87, a water outlet hose 88 in which is embedded a
power cable, and a gas inlet hose 89, these three hoses
all being enclosed adjacent to the docking body 200 by
a sheath 206 which also covers the upper end of the
docking body 200. It will be appreciated that the
welding unit 85 is utilized in applications which do
not require it to move to follow a welding path, such
as repeated spot welds, or where the workpiece is moved
relative to the welding unit 85.
The construction and operation of the we!ding unit
55 of FIG. 1 will now be described in greater detail.
Referring to FIGS. 3-8 of the drawings, the docking
body 100 includes a solid cylindrical metal body 101,
which may be formed of brass. The body 101 has an annu-
lar channel or recess 102 formed in the outer surface
20 thereof adjacent to the input end thereof for receiving
a clamp 103 (see FIG. 3) securely to clamp the adjacent
end of the delivery conduit sheath 70. Also formed in
the outer surface of the body 101 is a circumferential
groove 104 (FIG. 7) in which is received a resilient
split positioning ring 105, for a purpose to be
explained more fully below. The outlet end of the body
101 is externally threaded, as at 106. The body 101
has circular input and output end faces 107 and 108
between which are formed an axial bore or passage 110.
-11-
~2S6~
Referring in particular to FIG. 7, the passage 110
has an enlarged counterbore input end portion 111, and
two successively larger counterbore portions 112 and
113 at the output end. Also extending through the body
101 from the input face 107 to the output face 108 is a
gas passage 114 (FIG. 8) which has an enlarged counter-
bore portion 115 at the input end thereof opening to
the input face 107, and is provided adjacent to the oth-
er end thereof with an inclined spur portion 116 which
communicates with the counterbore portion 113 of the ax-
ial passage 110 a slight distance inwardly of the out-
put face 108.
Also extending through the body 101 from the input
face 107 to the output face 108 are a water input pas-
sage 117 and a water drain passage 118 (see FIG. 7),
which are similar in construction and are both substan-
tially parallel to the axial passage 110. Each of the
passages 117 and 118 has an enlarged-diameter counter-
bore portion 119 at its input end which comrnunicates
via a slightly angled portion 120 with the main pas-
sage. Each of the passages 117 and 118 is also provid-
ed adjacent to the output end thereof with a plurality
of successively larger diameter counterbore portions
121, 122, 123, 124 and 125.
A wire guide fitting 126 is received in the
counterbore portion 111 of the axial passage 110 for
guiding the metal wire electrode M from the electrode
casing 71 into the passage 110. The fitting 126 is pro-
: vided with a circumferential groove 127 which receives
a set screw 128 threadedly engaged in a radial bore 129
- 12-
~25616~
in the body 101 for fixedly securing the fitting 126 in
place (see FIG. 8). Respectively brazed in place in
the counterbore portions 115 and 119 of the passages
114, 117, and 118 are a water input fitting 130, a wa-
ter output fitting 131 and a gas fitting 132. Each of
these fittings is provided with an externally threaded
portion adapted to be threadedly coupled to a mating
fitting at the end of the associated one of the con-
duits 71-74 for transferring water and gas to the body
101 and receiving water from the body 101. In this re-
gard, it will be appreciated that the water drain fit-
ting at the end of the drain hose 73 is designed to
also terminate the electric power cable which is car-
ried within the drain hose 73. Accordingly, the elec-
trical welding potential is coupled via the fitting 131
to the conductive metal body 101 in a known manner.
Also provided in the body 101 adjacent to the threaded
portion 106 is a radial bore 133 in which is threadedly
received a set screw 134 for a purpose to be explained
below.
Each of the water passages 117 and 118 is provided
with a check valve 135 (FIG. 7) which includes a
helical compression spring 136 seated in the counter-
bore portion 121 for resiliently urging a valve ball
137, disposed in the counterbore portion 122, against
an annular seat 138 which is threadedly engaged in the
counterbore portion 123, for closing the passage
therethrough.
Fixedly secured to the body 101 at the output end
thereof is an output fixture 140, which is of known con-
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~256~
struction and cooperates with the body 101 to form the
inner body of the welding unit 55, analogous to the
inner body construction disclosed in my U.S. Patent No.
3,775,584. The output fixture 140 includes a
cylindrical inner tube 141 (FIG. 8) having a reduced-
diameter tip 142 which is received in the counterbore
portion 112 of the axial passage 110 and is provided
with a radial aperture 143 therein disposed for align-
ment with the bore 133 in the body 101. The inner tube
141 also has a radially outwardly extending annular
flange 144 dimensioned to seat at the bottom of the
counterbore portion 113 of the passage 110 and is there
brazed in place. The outer end of the inner tube 141
projects well beyond the output face 108 of the body
101 and is internally threaded, as at 145.
, Telescopically received over the outer end of the
inner tube 141 is a cylindrical sleeve 146 (FIG. 8) hav-
. ing a diameter slightly greater than the diameter of
~, the counterbore portion 113 of the passage 110. The
~,
sleeve 146 has a reduced-diameter end 147 adapted to be
slidingly received into the counterbore portion 113 and
brazed to the body 101. The sleeve 146 is dimensioned
to be spaced radially from the inner tube 141, except
~ at the outer ends thereof where they are brazed togeth-
;~ er, the sleeve 146 and the tube 141 cooperating to de-
fine therebetween an annular chamber 148 which
communicates at its inner end with the spur portion 116
of the gas passage 114. Formed in the sleeve 146 adja-
cent to the outer end of the chamber 148 are a plural-
: :
-14-
~ 2`56167
ity of circumferentially spaced-apart gas exit holes
149.
Removably mounted on the output fixture 140 is a
welding tip assembly, generally designated by the numer-
al 150, which is substantially of conventional construc-
tion. The tip assembly 150 includes a tubular adapter
151 provided with an externally threaded lug 152 at one
end thereof adapted to be threadedly engaged with the
internally threaded portion 145 of the output fixture
140 and locked in place by a jam nut 153. Flats 154
may be formed on the outer surface of the adapter 151
to receive an associated tool to facilitate mounting
and demounting of the adapter 151. Threadedly received
in the adapter 151 at its distal end is a contact tip
155.
It will be appreciated that the tip assembly 150
guides the welding wire electrode M to the associated
workpiece, the contact tip 155 preferably having an in-
ner diameter only very slightly greater than the diam-
eter of the welding wire electrode M. In this regard,there is typically provided a flexible wire support lin-
er 156 which extends through the axial passage 110 in
the body 101 from the fitting 126 and through the
output fixture 140 and the adapter 151 to provide
accurate guiding of the metal electrode wire M
therethrough. The wire support liner 156 is held in
place by the set screw 134 so that it cannot fall out
in the event that the adapter 151 and/or the contact
tip 155 are removed. While a threaded contact tip 155
has been illustrated, it will be appreciated that other
-15-
~256i6~
known types of contact tips, such as that disclosed in
FIG. 18, could be utilized.
Referring now in particular to FIGS. 3 and 9-14,
the nozzle assembly 160 will be described in detail.
The nozzle assembly 160 illustrated is of a long-reach,
slim-line, water-cooled style, but it will be appreciat-
ed that different types of welding nozzle assemblies
are utilized for different applications, and the nozzle
assembly 160 could be of any of these general types.
It will likewise be appreciated that the tip assembly
150 will have a length corresponding to the length of
the associated nozzle assembly 160. Also, while the
nozzle assembly 160 is of the water-cooled type, it
will be appreciated that the principles of thé present
invention are applicable to air-cooled nozzle
assemblies.
The nozzle assembly 160 includes an elongated cy-
; lindrical inner tube 161 provided on the outer surface
thereof with two elongated flat planar portions 162.
The distal or output end of the inner tube 161 has an
enlarged-diameter portion 163. Also formed on the in-
ner tube 161 and spaced longitudinally a slight dis-
tance from the enlarged-diameter portion 163 is a
radially outwardly extending circumferential rib or
flange 164 which cooperates with the enlarged-diameter
portion 163 to define therebetween an annular channel
164a (FIG. 11). The flat portions 162 extend through
the circumferential flange 164 into the channel 164a,
as can best be seen in FIGS. 11 and 13.
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The inner tube 161 is disposed telescopically with-
in an outer tube 165, the distal end of which abuts the
circumferential flange 164, with the input ends of the
inner and outer tubes 165 being substantially flush
with each other. The inner and outer tubes 161 and 165
contact each other around the entire circumference
thereof, except at the flat portions 162. The inner
and outer tubes 161 and 165 are brazed together at the
input ends thereof and at the circumferential flange
164, the outer tube 165 being provided with two circu-
lar openings 166 therethrough disposed for alignment,
respectively, with the flat portions 162, as can best
be seen in FIGS. 12 and 14. In this regard, the flat
portions 162 are preferably not diametrically opposed
on the inner tube 161. This facilitates assembly of
the parts, insuring that they can properly be mated in
only one orientation.
The input end of the outer tube 165 is telescop-
ically received within a transfer collar 167 and is
brazed thereto, the transfer collar 167 having a radial-
Iy inwardly extending circumferential flange 167a which
limits the depth of insertion of the outer tube 165
therein. The transfer collar 167 has two longitudi-
nalIy-extending flat portions 168 on the outer surface
thereof, respectively disposed for longitudinal
alignment with the flat portions 162 on the inner tube
161. Formed through the transfer collar 167, respec-
tively at the outer ends of the two flat portions 168,
are two holes 169, respectively disposed in registry
with the holes 166 in the outer tuhe 165 (see FIGS. 12
~,~256167
and 14). The input end of the transfer collar 167 has
a counterbore portion 169a on the inner diameter there-
of (see FIG. 10).
A cylindrical sleeve 170 telescopically surrounds
the transfer collar 167 and is brazed thereto at the
output end thereof, the sleeve 170 contacting the trans-
fer collar 167 along substantially the entire outer sur-
face thereof except for the flat portions 168. Fixedly
secured to the sleeve 170 at its input end is an annu-
lar mounting collar 171 having a circular groove 172 in
one face thereof in which the adjacent end edge of thesleeve 170 is seated and brazed in place. The mounting
collar 171 is provided at its inner surface with a cy-
lindrical flange 173 which is dimensioned to fit within
the counterbore portion 169a of the transfer collar
167, being brazed thereto. Two ports 174 are formed
through the mounting collar 171 in position for align-
ment, respectively, with the flat portions 168 on the
transfer collar 167 (see FIGS. 10 and 14). Secured to
the mounting collar 171 are two tubular metal connect-
ors 175, each having a reduced-diameter tip 176 which
is received in an enlarged counterbore portion of a cor-
responding one of the ports 174 and brazed thereto.
Each of the connectors 175 is provided with an
externally threaded portion 177 (FIG. 3) at its outer
end.
The connectors 175 are received through bores 179c
in an annular insulator collar 179 (FIG. 10), which is
formed of an electrically insulating material such as
polytetrafluoroethylene. The insulating collar 179 has
~25616~
a cylindrical portion 179a on its inner surface which
projects inwardly through the central bore in the annu-
lar mounting collar 171, the cylindrical portion 179a
preferably being provided with a surrounding O-ring
seal 179b which is seated in an annular recessed por-
tion of the mounting collar 171.
Respectively threadedly engaged with the connect-
ors 175 are two identically-constructed tubular water
transfer fittings 180 (FIGS. 3, 9 and 10), each of
which is provided with a hexagonal portion 181 to facil-
itate mounting and demounting, and two circumferential
grooves 182 in which are respectively received 0-ring
seals 183. Each of the fittings 180 is provided with a
tubular actuator tip 185 having slots 186 in the side
surface thereof adjacent to the distal end thereof, for
a purpose to be explained more fully below.
Telescopically received within the inner tube 161
are a short cylindrical insulating sleeve 188 and an
long cylindrical insulating sleeve 187, spaced apart by
a gas diffuser ring 190, all being formed of suitable
electrically insulating materials. The gas diffuser
ring 190 has a plurality of circumferentially spaced-
apart bores 191 therethrough (see FIGS. 10 and 13).
The inner diameter of the gas diffuser ring 190 is
dimensioned to just slidably fit over the adapter 151
of the tip assembly 150, as indicated in FIG. 10.
Telescopically received over the distal end of the
inner tube 161 is a cylindrical adapter sleeve 192, pro-
vided with a radially inwardly extending circumferen-
tial flange or shoulder 193 which limits the depth of
- 1 9-
s2s6~6~
insertion of the inner tube 161 therein at a position
wherein the adapter sleeve 192 just overlaps the distal
end of the outer tube 165. The adapter sleeve 192 is
brazed to both the inner and outer tubes 161 and 165
and cooperates therewith to close the annular channel
164a.
The outer end of the adapter sleeve 192 extends
well beyond the adjacent end of the inner tube 161 and
is internally threaded, as at 194, for threadedly re-
ceiving therein a cylindrical gas nozzle 195. The tip
the gas nozzle 195 is provided with a substantially
frustoconical outer surface 196 and two diametrically
opposed flattened portions 197 to facilitate applica-
tion of an associated tool to aid in mounting and de-
mounting of the gas nozzle 195. The inner end of the
gas nozzle 195 abuts the adjacent end of the insulating
sleeve 188, while the circumferential flange 167a on
the transfer collar 167 abuts the adjacent end of the
insulating sleeve 187, securely to hold the insulating
sleeves 187 and 188 and the gas diffuser ring 190 in
place. The gas nozzle 195 has an inner diameter sub-
; stantially greater than the outer diameter of the tip
assembly 150 which extends coaxially thereinto.
It will be appreciated that the adapter 151 cooper-
~1 ates with the insulating sleeves 187 and 188 and the
gas nozzle 195 to define therebetween an annular gas
passage 198, best illustrated in FIG. 10, this passage
including the bores 191 through the gas diffuser ring
190. Referring to FIG. 3, the nozzle assembly 160 is
also provided with a cone nut 199 (FIG. 3), formed of a
:,
-20-
125S~67
suitable electrically insulating material, and having
an internal shoulder 199a for mounting the nozzle assem-
bly 160 in place on the docking body 100, as wiII be
explained below.
The assembly and operation of the welding unit 55
wilJ now be explained. Initially, the docking body 100
is coupled to the utilities delivery hose conduits
71-74 by the fittings 126, 130, 131 and 132, and the
sheath 70 is clamped around the body 101 with the clamp
103. Then, the threaded end 106 of the body 101 is
dropped into the gun mounting bracket 53, the position-
ing ring 105 engaging the top of the mounting bracket
53 to limit the depth of insertion of the body 101
therein. This accurately positions the docking body
100 with respect to the robot wrist 52 and, therefore,
with respect to the associated workpiece. The mounting
bracket 53 is secured tightly about the docking body
100. The tip assembly 150 may be mounted to the output
fixture 140 either before or after mounting of the dock-
ing body 100 on the mounting bracket 53.
The welding unit 55 is now ready for mounting of
the nozzle assembly 160. In this regard, it is a funda-
mental feature of the present invention that the nozzle
assembly 160 can be quickly and easily manually mounted
and demounted with respect to the docking body 100,
without the use of tools. More specifically, referring
in particular to FIG. 3, the nozzle assembly 160 is
slipped up over the tip assembly 150, the tip assembly
150 being slidably received through the gas diffuser
ring 190, as indicated in FIG. 10. The water transfer
` ~2S~67
fittings 180 are respectively received in the recepta-
cles formed by the multiply-counterbored portions of
the water passages 117 and 118 until the insulator col-
lar 179 abuts the output face 108 of the docking spool
body 101, as is best illustrated in FIG. 9.
In this mounted condition the water transfer fit-
tings 180 cooperate with the passages 117 and 118 to
form plug-and-socket type couplings, the counterbore
portions 125 accommodating the hexagonal portions 181
of the water transfer fittings, and the counterbore por-
tions 124 frictionally receiving the O-rings 183 there-
in in sealing relationship therewith. The actuator
tips 185 are respectively received through the annular
seats 138 of the check valves 135 for depressing the
balls 137 against the urging of the compression springs
136 to open the check valves and permit the free flow
of water through the passages 117 and 118, as illustrat-
; ed in FIG. 9. The cone nut 199 is then slipped up over
: the distal end of the nozzle assembly 160 and is
threadedly engaged with the threaded portion 106 of thebody 101, the shoulder l99a engaging the mounting
collar 171 securely to lock the nozzle assembly 160 in
its mounted condition, illustrated in FIG. 1.
When the welding unit 55 is thus assembled, the
arc shielding gas flows through the gas passage 114 in
the body 101 into the annular chamber 148 in the output
.~ fixture 140, through the gas exit holes 149 therein in-
to the nozzle assembly 160 and, particularly, into the
passage 198, and through the gas diffuser ring 190 to
-22-
" ~2s6~6~
c e gas nozzle 195, where it surrounds the contact tip
155 to shield the welding arc in a known manner.
The cooling water flows through the water input
passage 117 and the open check valve 135 therein and
through the slots 186 in the actuator tip 185 of the
corresponding water transfer fitting 180. The water
then flows through the water transfer fitting 180, the
associated connector 175 and the associated port 174 of
the mounting collar 171 to a channel formed between the
sleeve 170 and the transfer collar 167 by the corre-
sponding one of the flat portions 168. The water then
flows through the aligned holes 166 and 169 to the chan-
nel between the inner and outer tubes 161 and 165 of
the nozzle assembly 160, formed by the corresponding
one of the flat portions 162. Water then flows down
along the nozzle assembly 160 to the annular channel
164a, where it circulates around the distal end of the
nozzle assembly 160 and then back up along the channel
formed by the other one of the flat portions 162. The
water returns in like manner through the other water
transfer fitting 180 and through the drain passage 118
in the body 101 via the open check valve 135 therein to
the water drain hose 73.
It will be appreciated that the electrical welding
current is applied to the metal wire electrode through
the body 101, the output fixture 140 and the tip assem-
bly 150 which are all in electrical contact with one an-
other, in a known manner. Also, it can be seen that
the insulator collar 179, the insulating sleeves 187
and 188, the gas diffuser ring 190 and the cone nut 199
~256~
insure complete electrical insulation of the nozzle as-
sembly 160 from the welding potential.
When it is desired to remove the nozzle assembly
160, such as when the gas nozzle 195 becomes clogged
with welding spatter, or is damaged or for any other
reason, one need only unscrew the cone nut 199 and sim-
ply pull the nozzle assembly 160 from the docking body
100. The bias springs 136 will automatically close the
check valves 135 to prevent any water spillage from the
docking body 100, thus obviating disconnection of the
cooling water at the water supply. A new nozzle assem-
bly 160 can be simply and easily installed in place in
the manner described above, without any necessity for
using tools or for in any way disturbing the docking
body 100 or any other part of the welding unit 55 or
the arc welding system 50, including the utilities
supplies.
If it were necessary to change the tip assembly
150 for any reason, this could very easily be done
also. While it would require the use of a wrench or
the like, it would not necessitate disturbing the dock-
ing body 100 or any other part of the arc welding sys-
tem 50, including the utilities supplies. It will also
be appreciated that if the docking body 100 needs to be
removed, for servicing or any other reason, it can be
reinstalled without loss of the critical positioning
with respect to the associated robot, since the posi-
tioning ring 105 will insure that it is repositioned at
exactly the same distance from the workpiece. Thus no
recalibration of the welding system 50 will be neces-
-24-
æ6i67
sary and the welding program can be resumed where it
was interrupted.
The welding unit 85 illustrated in FIG. 2 will now
be described. Referring in particular to FIGS. 15-19,
the docking body 200 includes a solid cylindrical met-
al body 201, which may be formed of brass. The body
201 has an enlarged-diameter portion 202 which has an
externally threaded end 203. Formed in the outer sur-
face of the enlarged-diameter portion 202 is a circum-
ferential groove 204 which is adapted to receivetherein an annular lip (not shown) of the sheath 206
for attaching the sheath 206 to the body 201.
The body 201 has a circular input end face 207 and
a circular output end face 208, between which extends
an axial cylindrical passage 210 through the body 201.
The passage 210 has an enlarged-diameter, internally-
threaded counterbore portion 211 at its input end, and
is provided at its output end with successively larger-
diameter counterbore portions 212 and 213. The wire
guide 86 is threadedly engaged in the counterbore
portion 211 of the passage 210, being locked in place
by a set screw 215 which is threadedly engaged in a
radial bore 214 in the body 201 (FIGS. 18 and 19).
Also formed in the body 201 is a radial bore 216 which
communicates with the counterbore portion 212 and in
which is threadedly engaged a set screw 217, for a
purpose to be explained below.
Formed in the body 201 is a gas passage 220, the
main portion of which is formed by providing a longitu-
dinal bore in the output face 208. The passage 220 is
L2s6~
provided with a radially extending input portion 221
spaced a predetermined distance from the input face 207
of the body 201. The gas passage 220 is sealed at the
output face 208 by a cap 222, and is provided with an
angled spur portion 223 which communicates with the
counterbore portion 213 of the axial passage 210. The
radial input portion 221 is provided with a large-
diameter counterbore portion 224 in which is received a
gas input fitting 225 which is brazed in place. The
fitting 225 is provided with an externally threaded con-
nector 226 extending therefrom perpendicular thereto,
as is best illustrated in FIG. 16.
Also formed in the body 201 are a water input pas-
sage 227 (FIG. 19) and a water drain passage 228, which
includes bores 229 and 229a (FIG. 17) extending from
the output face 208 of the body 201 substantially paral-
lel to the axial passage 210, and terminating short of
the input face 207. The water input passage 227 and
the bore 229 of the water drain passage 228 are each
provided with successively larger-diameter counterbore
portions 230, 231, 232, 233, and 234 (see FIG. 19),
each of these passages being provided with a check
valve 135 identical to that described above in connec-
tion with the welding unit 55. Communication between
the bores 229 and 229a of the water drain passage 228
is provided by two parallel transfer bores 236 (FIGS.
17 and 19), which extend generally along a chord of the
body 201, these bores being closed at their outer ends
by caps 237 and the bore 229a being closed at its outer
end by a cap 222a. Each of the passages 227 and 228
-26-
~Z56~67
has a radial portion 238 spaced a predetermined dis-
tance from the input face 207 of the body 201. The ra-
dial portions 238 each have enlarged-diameter
counterbore portions in which are respectively seated
fittings 235 and 239 which are brazed in place. The
fitting 235 is provided with a connector 226 projecting
perpendicularly therefrom in the same manner as de-
scribed above with respect to the fitting 225. The con-
nectors 226 and the fitting 239 are all arranged so
that their axes converge to one side of the body 201 to
facilitate consolidation of the associated utilities
conduits in a common sheath 206. In this regard, it
will be appreciated that the sheath 206 is adapted to
enclose the fittings 225, 235 and 239.
The docking body 200 is provided with an output
fixture 140 substantially identical to that described
above in connection the welding unit 55, which is
received in the counterbore portions 212 and 213 of the
axial passage 210, and is there brazed in place.
Mounted on the output fixture 140 is a tip assembly 250
which includes an elongated tubular adapter 251 having
a hexagonal outer surface with a reduced cylindrical
portion 257 at its output end, and an externally thread-
ed lug 252 at its input end which is threadedly engaged
with the output fixture 140 and locked in place with a
jam nut 253. The other end of the adapter 251 is inter-
nally threaded, as at 254, for threadedly receiving
therein a collet nut 255 in which a contact tip 256 is
slidably telescopically received. When the collet nut
255 is tightened, it clamps the contact tip 256 in
LZ56167
place in a known manner. Preferably, there is also pro-
vided a wire support liner 156 identical to that de-
scribed above in connection with FIG. 8, which extends
from the wire guide 86 through the axial passage 210
and the adapter 251 to the collet nut 255 for accurate-
ly guiding the wire electrode M to the contact tip 256,
the wire support liner 156 being locked in place by the
set screw 217.
While the tip assembly 250 has been illustrated as
being of the type utilizing a slip-in contact tip 256,
it will be appreciated that other types of known tip as-
semblies could be used, such as that illustrated in
FIG. 25, which will be described more fully below.
Referring now also to FIGS. 20-24, the nozzle as-
sembly 260 will be described. The nozzle assembly 260
includes an elongated, cylindrical inner tube 261 hav-
ing a reduced-diameter portion 262 at is outer end.
The outer surface of the inner tube 261 is provided
with two spaced-apart longitudinally extending flat por-
tions 263 which extend the length thereof, and are pref-
erably not diametrically opposed. The inner end of the
inner tube 261 has a counterbore portion 264 on its in-
ner diameter (FlG. 20). The inner tube 261 is telescop-
ically received within a cylindrical outer tube 265
which is slightly longer than the inner tube 261 and is
provided with a reduced-diameter portion 266 and its in-
put end.
Telescopically received within the inner tube 261
is a cylindrical insulator 270, formed of a suitable
electrically insulating material. The insulator 270
-28-
~256~.67
has a reduced-diameter portion 271 at its input end
with an elongated counterbore portion 272 and a short-
er, larger-diameter counterbore portion 273 at its out-
put end. Seated within the counterbore portion 273 is
; an annular gas diffuser ring 275, which has a circumfer-
ential groove 276 in the outer surface thereof adjacent
to the input end thereof. As is best illustrated in
FIGS. 22-24, the gas diffuser ring 275 is provided with
three r,adially-spaced apart rows of circumferentially
spaced apart holes 277 therein extending parallel to
the axis thereof. The outer row 278 extends only from
the groove 276 to the output face of the gas diffuser
ring 275~ The two inner rows 279 extend all the way
through the gas diffuser ring 275 from the input face
~, to the output face thereof, the outer one of these two
inner rows communicating with the groove 276. The in-
' ner surface of the ring 275 is counterbored at its
input end to form an annular shoulder 274 (FIG. 24)
', against which the cylindrical portion 257 of the
adapter 251 abuts (see FIG. 20).
The nozzle assembly 260 is also provided with an
annular mounting collar 280 having a circular groove
281 in one face thereof in which is seated the reduced-
diameter portion 266 of the outer tube 265 for brazing
thereto. The mounting collar 280 is provided with a cy-
lindrical flange 282 projecting therefrom and received
within the counterbore portion 264 of the inner tube
261 for brazing thereto. The flange 282 serves to de-
fine an annular shoulder 283 against which the reduced-
diameter portion 271 of the insulator 270 is seated,
56~6q
the larger-diameter portion of the insulator 270 being
seated against the end face of the cylindrical flange
282. Formed through the mounting collar 280 are two
ports 284 positioned respectively to be aligned with
the flat portions 263 of the inner tube 261. Seated in
the ports 284 and brazed to the mounting collar 280 are
two connectors 175 identical to those described above
in connection with the nozzle assembly 160. The nozzle
assembly 260 is also provided with an insulator collar
179 like that described in connection with the nozzle
assembly 160, the cylindrical portion 179a of the insu-
lator collar 179 extending within the insulator 270.
Water transfer fittings 180 identical to those de-
scribed above in connection with the nozzle assembly
160 are respectively threadedly engaged with the con-
nectors 175.
The nozzle assembly 260 is also provided with a cy-
lindrical adapter sleeve 290, having a counterbore por-
tion 291 at the input end thereof dimensioned to be
received telescopically over the reduced-diameter por-
tion 262 of the inner tube 261 and brazed thereto. The
outer end of the adapter sleeve 290 has an enlarged-
diameter portion which forms a shoulder 292 against
which the outer end of the outer tube 265 is seated,
the adapter sleeve 290 being brazed to the outer tube
265. The outer end of the adapter sleeve 290 is inter-
!~ nally threaded, as at 293. Threadedly received within
the adapter sleeve 290 is a cylindrical gas nozzle 295,
the outer end of which has a frustoconical outer sur-
face 296 provided with diametrically spaced-apart flat
-30-
12~;6~67
portions 297 to facilitate application of an associated
tool.
Referring to FIG. 20, it will be appreciated that
when the gas nozzle assembly 260 is mounted in place on
the welding unit 85, the tip assembly 250 is received
coaxially therethrough. In this regard, the shoulder
274 of the gas diffuser ring 275 is seated against the
end of the cylindrical portion 257 of the adapter 251
being secured in place by the collet nut 255. The tip
assembly 250 cooperates with the insulator 270 and the
gas nozzle 295 to form an annular passage 298 there-
between for the arc shielding gas, the passage 298 ex-
tending through the gas diffuser ring 275. More
specifically, it will be appreciated that the gas flows
through successively larger-diameter channels to the
gas nozzle 295, exiting the output fixture 140 to flow
into the portion of the passage 298 along the inner end
of the insulator 270, then into the larger-diameter
counterbore portion 272 of the insulator 270. ~he gas
then flows directly through the inner two rows 279 of
holes 277 in the gas diffuser ring 275 to the gas noz-
zle 295. The gas in the outer one of these inner two
rows of holes 279 also flows radially outwardly through
the groove 276 to the outer row 278 of holes 277. This
arrangement has been found to provide an improved con-
trol of the gas flow to the welding arc.
Referring to FIG. 25, there is illustrated an al-
ternative form of contact tip 256a which could be used
in place of the contact tip 256. The contact tip 256a
is a threaded tip, similar to that illustrated in FIG.
~Z5616'7
~. However, the tip assembly 150 illustrated in FIG. 8
cannot be used with the nozzle assembly 260, since the
gas diffuser ring 275 would fall out when the gas noz-
zle 295 is removed. Accordingly, in the embodiment of
~IG. 25, there is provided a coupler nut 255a which is
threadedly received in the end of the adapter 2Sl, in
the same manner as the collet nut 255. However, the
coupler nut 255a is internally threaded to receive
therein the threaded contact tip 256a. The hexagonal
portion of the coupler nut 255a has external dimensions
greater than the inner diameter of the gas diffuser
ring 275 so as to retain the ring 275 in place.
A cone nut 299 (FIG. 2) of suitable electrically
insulating material is telescopically received over the
nozzle assembly 260 and threadedly engaged with the
threaded portion 203 of the body 201 to lock the nozzle
assembly 260 in place on the docking spool 200, in sub-
stantially the same manner as was explained above in
connection with the nozzle assembly 160.
The assembly and operation of the welding unit 85
is substantially similar to the of the welding unit 55.
Initially, the fittings 225, 235 and 239 are coupled
to the utilities supply hoses 87-89 and the sheath 206
is mounted in place. The wire guide 86 is mounted on
the docking body 200 and then locked in place in the
wire feeder 81 for supporting the welding unit 85. The
tip assembly 250 may be mounted in place on the output
fixture 140 either before or after mounting of the dock-
ing body 200 to the wire feeder 81.
6~67
The nozzle assembly 260 may then be manually fit-
ter over the tip assembly 250 and plugged into the dock-
ing body 200 in substantially the same manner as was
explained above with respect to the welding unit 55,
and locked in place by the cone nut 299. The water
; transfer fittings 180 operate the check valves 135 in
the same manner as was described above with respect to
the embodiment of FIG. 1. The gas flows through the
fitting 225 and the gas passage 220 to the output fix-
ture 140. The water flows in through the fitting 235,
the passage 227, the corresponding one of the water
transfer fittings 180 and thence through the mounting
collar 280 to the longitudinal channel between the in-
ner and outer tubes 261 and 265 formed by the corre-
sponding one of the flat portions 263. The reduced
diameter portion 262 of the inner tube 261 forms an
annular channel through which the water flows
circumferentially around the inner tube 261, returning
up along the other flat portion 263 and the other water
transfer fitting 180 to the drain passage 228 in the
docking spool body 201. More particularly, the water
flows through the bore 229, across the transfer bores
;~ 236 to the bore 229a and then out through the fitting
239.
While the nozzle assembly 260 has been illustrated
in connection with the welding unit 85, it will be ap-
preciated that other styles of water-cooled welding noz-
! zles could be used, such as the nozzle assembly 160
described above. Thus, it can be seen that it is a sig-
nificant aspect of the present invention that a variety
'
~ -33-
~2561~;7
of different types of water-cooled welding nozzle assem-
blies can all be interchangeably mounted on the docking
bodies 100 or 200, without necessitating any disconnec-
tion or other alteration of the rest of the welding sys-
tem, and in particular the utilities supplies.
From the foregoing, it can be seen that there has
been provided an improved welding system and a docking
-ssembly therefor which is of simple and economical con-
struction, and which affords simple and quick manual
mounting and demounting of nozzle assemblies without
the use of tools and without in any way affecting the
utilities supplies, and without losing the precise posi-
tioning of the welding unit with respect to the
workpiece.
-34-
