GB2285404A - Water-cooled welding torch - Google Patents

Abstract

The supply of water to the water jackets in the torch is fed through feed and return hoses, clamped to pipe spigots 36. The spigots 36 are a self-locking-taper fit in a block 29, and are drawn into the block with a draw-ring 52 using bolts 60. This spigot-to-block connection is highly robust, has good electrical conductivity, and is well-sealed against water leakage. The electrical supply to the arc is fed through two cables 49, which lie inside the feed and return water hoses. <IMAGE>

Description

\L'ATER-COOLED WELDING TORCH This invention relates to welding torches. and to the equipment ancillary to such torches. In particular, the invention relates to the supply of cooling water and other fluids from a service station to the torch.

One of the problems facing the designer of welding torches is that the conduit connecting the torch to the service station should be flexible and easily manipulable, and yet the conduit should be strong, and especially it should be resistant to kinking and creasing.

The invention is especially advantageous in this regard. In the invention, the electrical current is fed from the service station to the torch by two electrical cables. The two cables pass one inside the water feed pipe and the other inside the water return pipe, within the conduit. Dividing the cable into two turns out to be highly advantageous: surrounding each of the two cables by water means that the cables run cool even when transmitting heavy currents: and providing a metal cable inside the (rubber) water pipes renders each pipe highly resistant to kinking.

Thus, both the water pipes and the cables each take benefit from being placed together.

It is the conventional practice, in water cooled welding torches, to clamp the rubber water pipes to brass pipe-spigots, and the conventional arrangement is that the pipe spigot is screwthreaded into a block. The invention provides an alternative to the normal practice of providing a screw thread connection between the pipe-spigot and the block.

The invention provides a piug-and-socket connection between the pipe-spigot and the block. A draw ring is provided for drawing the plug into the socket. A bolt extends from the block, and makes a screw thread connection whereby the draw ring may be urged forcefully relative to the block, thereby tightening the plug into the socket.

Preferably, provision is made also for forcefully loosening the plug from the socket: when this is done, the plug and socket connection can be of the self-locking-taper type, which is very efficient and reliable from the standpoints of mechanical strength, electrical conductivity, and watertightness.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT By way of further explanation of the invention, exemplary embodiments of the invention will now be described with reference to the accompanying drawings, in which: Fig 1 is a cross-sectional side view of a portion of a water-supply system for a welding torch, which embodies the invention; Fig 2 is a diagrammatic view, shown end-on, of a draw-ring component of the system shown in Fig 1; Fig 3 is a cross-sectional side view of another portion of the water-supply system shown in Fig 1; Fig 4 is a view on line 4-4 of Fig 3; Fig 5 is a section on line 5-5 of Fig 3; Fig 6 is a pictorial view of a welding torch; Fig 7 is a view corresponding to Fig 3 of another embodiment of the invention.

Fig 8 is a cross-section of a welding torch; Fig 9 is a cross-section of a handle of the torch of Fig 8; Fig 10 is a cross-section on line C-O of Fig 8; Fig 11 is a cross section on line P-P of Fig 9; Fig 12 is a cross-section, like Fig 11, of another torch; Fig 13 is a cross-section of the handle area of another torch; Fig 14 is a cross-section of a portion of the handle of another torch.

The apparatuses shown in the accompanying drawings and described below are examples which embody the invention. It should be noted that the scope of the invention is defined by the accompanying claims, and not necessarily by specific features of exemplary embodiments.

In the drawings, numerals used in more than one drawing refer to the same or essentially similar components.

For a welding operation of the type with which the invention is concerned, it is the usual practice to provide a service station. This service station provides: a welding current of electricity; antioxidising gas; a motor for feeding welding wire to the weld; (optionally) a vacuum source for extracting fumes; and, in the particular case with which the invention is concerned, a pumped supply and return of cooling water for the hand-held welding torch.

These services as supplied from the service station are fed to the welding torch through various pipes and tubes forming a main conduit 10. The conduit 10 is flexible in order to allow the torch to be manipulated by the welding operator.

The service station includes, as shown in Fig 1, a fixture 12. The fixture 12 is connected to the source of welding current in the service station via a lug 14.

The anti-oxidising gas, being argon, carbon dioxide, or as required, is fed into the fixture 12, via a port 16.

The fixture 12 is formed with a through-hole into which is received a stem 18. The stem 18 is detachable from the fixture 12, being held in place by means of a bolt 20. With the stem present in the fixture, welding wire 23 is inserted into the stem; the wire is on a motorised reel, whereby the wire may be fed forward controllably, in the conventional manner.

The wire 23 is received inside a close-coiled helical spring 25, which serves as a guide for the wire on its passage to the welding torch. A length of plastic tubing 27 is fitted to the stem 18; gas from the port 16 is conveyed inside the tubing 27, along with the spring 25 and the wire 23.

So far, the above-described arrangements for supplying the welding current, the welding wire, and the gas, into the flexible conduit follow conventional practice.

It is conventional also to provide a water supply to the torch, the water-feed and water-return pipes also being contained within the conduit. However, the particular manner in which the water-feed and -return pipes are arranged in the apparatus shown in Fig 1 is especially advantageous, as will now be described.

The stem 18 carries a block 29, which is brazed to the stem. A water feed port 30 and a corresponding water return port 32 are provided in the block 29.

The ports 30,32 communicate with respective sockets 34. Each socket 34 is of conically tapered form.

Respective pipe-spigots 36 are inserted in the sockets 34. A plug end 38 of the pipespigot is a taper fit into the socket 34. An Spring 40 on the plug end 38 contains and seals water from the port 30.

The water enters the hollow interior 43 of the pipe spigot 36. A rubber tube 45 is clamped to the pipe spigot 36. Water from the hollow interior 43 of the pipe-spigot passes into the tube 45 via radial holes or slots 47.

When the plug-end 38 is inserted tightly in the socket 34, not only is the pipe-spigot 36 secured very well mechanically to the block 29, but also there is an excellent, low resistance, electrical contact between the pipe-spigot and the block.

A length of flexible electrical cable 49 is brazed or soldered into a hole 50 in the pipe-spigot.

Fig 1 shows the water-feed pipe 45. The water return pipe is of similar arrangement. Thus, both the water-feed pipe and the water-return pipe are equipped with flexible electrical cables. The large electrical current required in heavy-duty welding is thus split between two cables.

As compared with a single cable, dividing the electrical duty between two cables means that each cable can be a little less than half the currentcarrying cross-section than the corresponding single cable. The reason each half-cable can be a little less than half the size is that each half-cable is contained in its own respective water jacket, whereby cooling of the cable is enhanced.

When only a single cable was provided, as in conventional designs, the conduit 10 could be quite stiff. As a result, the welding operator found it quite tiring to operate the torch through a working day.

Splitting the cable into two, and placing two smallerthan-half cables one in the water-feed pipe and the other in the water-return pipe, results in a great improvement in physical flexibility and manipulability to the conduit; so much so as to extend by hours the period the operator can work comfortably.

In order to ensure the pipe-spigots 36 are pressed firmly into the sockets 34, a draw-ring 52 is provided.

The draw-ring has U-shaped cut-outs 54, which engage complementary recesses 56 defined between two collars 58 provided on the pipespigot.

The draw-ring 52 is separate from the block 29.

When the draw-ring is forced to move to the right (Fig 1), it urges the pipe-spigots 36 tightly into the sockets 34 in the block 29; when the draw-ring is forced to the left, it disengages the pipespigots from the block. The draw-ring 52 is moved to the right by tightening a bolt 60. To move the draw ring to the left, the bolt 60 is slackened, and then the head of the bolt may be tapped to the left to drive the pipespigots free from the sockets 34. (The angle of the taper in the sockets is such that the taper is selflocking.) The bolt 60 is screw-threaded into the draw-ring 52, and passes through a corresponding plain hole in the block 29.

The relative dispositions of the draw-ring 52, the bolt 60, and the pipe-spigots 36, is shown in Fig 2. It will be understood that the water feed and return ports 30 in the block 29 correspond to the layout as shown in Fig 2, although shown out of position in Fig 1. The draw-ring 52 does not touch the stem 18, in that a hole 63 in the draw ring provides adequate clearance.

As described, the conduit 10 includes the welding wire 23 inside its guide spring 25 surrounded by the gas-conveying plastic tubing 27; also the conduit includes the two electrical cables 49 inside their respective water-conveying rubber tubes 45. Thus, it will be noted that in the conduit 10, the three fluidconveying flexible pipes or tubes 27,45 all have respective central internal "cores" of metal; these "cores" serve to provide excellent resistance to kinking of the pipes and tubes, and to other types of mechanical failure.

The conduit 10 is therefore very sturdy in the sense of being able to resist the abuse which is always likely to be imposed upon it in a practical welding shop, especially abusive snaggings, twistings, and the like. On the other hand, none of the components of the conduit as described is thick and heavy, and therefore the conduit is light in weight, and is comparatively very flexible. It is easy for the operator to carry and manipulate a welding torch supported on such a conduit for long periods.

The conduit 10 includes, and is enclosed in, a conventional rubber/ canvas cover. The cover is not shown in Fig 1.

The other end of the conduit 10, where the conduit attaches to the welding torch, will now be described.

In Fig 3, the arrangement is repeated of a draw-ring that forces pipespigots into sockets in a block. The draw-ring is shown at 65, the pipe spigots at 67, and the block at 69.

The block 69 is brazed over a brass tube 72, which forms a component of the gooseneck of a welding torch 70 (Fig 6). The tube 72 is in turn brazed over a stem 74. The stem 74 is a thick-walled tube, the walls of which are cut flat as shown at 76 (Figs 3 and 4). The flats 76 thus define passages 78 between the stem and the tube, for conveying the feed and return water to and from the torch 70.

The internal layout of the torch is such as to route the cooling water around and through those components of the torch that tend to become hot during welding, and can be of any suitable design.

An example of a design of torch which is suitable for use with the invention is shown in European patent application EP-931202,778.2.

The block 69 is provided with tapered connections 80 for receiving the pipe-spigots 67. Holes are drilled from the outside of the block to connect the sockets with the passages 78. The outer portions of these holes are then plugged, as shown at 81 in Fig 3.

The draw-ring 65 has cut-outs for accommodating a recess between collars of the pipe-spigot 67, as was described in relation to Fig 1. Bolts 83 are provided for moving the draw-ring 65 to the left, and thereby clamping the pipe-spigots into the block 69.

At the service station as shown in Fig 1, the requirement, as far as the physical characteristics of the components was concerned, was to support the conduit 10 in a secure, robust fashion. At the torch end of the conduit, on the other hand, the requirements are different, in that now the main requirement is that the components should be light in weight; the components also should be physically small, especially as regards radial dimensions. As shown in Fig 4, the shape of the block 69 is not simply circular, but includes weight-reducing cutaways 85. Similarly, the draw-ring 65 may be trimmed to reduce the weight (Fig 5).

The components shown in Fig 3 fit inside a plastic handle 87 (Fig 6) of conventional type, which is moulded in two halves. A trigger is included in the handle, which, when operated, activates the welding current, starts the wire feed-motor, etc, back at the service station. The leads to the trigger are also present in the conduit 10.

It will be noted that the tube 72, which is present in the gooseneck of the torch, is electrically live: as is conventional, a sleeve of insulating material is slipped over the tube 72, and also a protective sleeve of metal is provided outside the insulating sleeve.

In some alternative types of welding torch, the water jacket of the torch is located radially outside the electrical insulation. An example is shown in Fig 7.

The invention can still be put into practice in this case, but of course the designer must see to it that the metal parts of the water jacket outside the insulator are isolated electrically from the welding current. This can be done by including short lengths of rubber tubing 89 (Fig 7) in the water feed and supply pipes.

Generally, the connection between the pipe-spigot 67 and the block 69 has to be such that the connection transmits the feed or return water without leakage thereof; the connection has to be such as to be electrically capable of transmitting welding currents (in the hundreds-of-amps range); and the connection has to be mechanically strong and robust, since the components are inevitably subjected to spurious twists, knocks, and other abusive. It is preferred that the design of the connection is such that, if a knock is so abusive that some failure occurs, that the failure takes the form of a bending of the spigot, rather than a rupture of the joint that might allow leakage of the water.

A comparison may be drawn between securing the pipe-spigots 67 into the block 69 by means of the tapered connections 80, as shown, with securing pipe-spigots into a block by means of screw-threads.

Because of the very tight restriction on the radial space envelope in the torch handle 87, the room available for the spigot-to-block connection, whatever its structure, is severely limited. It is recognised that if this small space were occupied by a screw-thread connection, the constraints would be so tight that the screw-thread connection at that location would be unreliable. That is to say: if the pipe-spigot were secured into the block by means of a screw-thread connection, the screw-thread would be so small that there would be a danger that the thread would strip, even with just a small degree of abuse. It may be noted also that the components in question are generally made of brass, which material has no great resistance to the stripping of threads if overtightened.

Moreover, the connection between the pipe-spigot and the block must be watertight, and it may be noted that it is difficult to make a screw thread watertight. In the case of a welding torch the requirement for watertightness is especially demanding in that even tiny drops of water leaking into the arc area will spoil the weld.

When the connection between the pipe-spigot and the block makes use of the plug and socket arrangement, with the pipe-spigots being drawn into the sockets by the action of the draw-ring, it will be understood that the above-described problems of screw-threads are largely alleviated. The draw-ring may be made of steel, and the bolts acting on the draw-ring are also of steel, which gives good strength, and in any case the draw bolt threads can be large and robust. It will be understood that even the most vigorous abuse is hardly likely to strip the threads of the connection between the draw bolt and the draw-ring. whereas even slight abuse could strip the threads in a corresponding spigot-to-block screw thread connection.

The connection as described has good electrical properties. When assembled, the pipe-spigot becomes tightly wedged into the socket, which gives an excellent, large-contact-area, electrical connection for the heavy welding currents.

Also, the connection as described has good watertightness properties. With the tapered-plug-insocket type of connection, the designer can easily specify the provision of an Spring, which gives reliable watertightness.

Preferably, the designer should make the pipe spigots 67 at the service-station end identical to the spigots 36 at the torch end. Although there is no premium on radial space at the service station end of the conduit, it is simpler to have components the same.

It is contemplated that plug-and-socket connections, as described, may be used in conjunction with the conventional screw-in connections. Thus, the pipespigots may be connected to the block at the torch end of the conduit by means of connections as described, whereas at the service station end, the pipe-spigots are connected by screwing the pipespigots into screw-threaded holes in the block. It will be understood that the screw-thread connection should be made first, when the pipe can rotate.

Although two pipes have been described, more than two may be provided. The draw-ring and draw bolt arrangement can be used to tighten more than two pipe-spigots into place (simultaneously) into suitable sockets.

The water jacket which is to be supplied with cooling water may be located deep inside the torch, and as close to the tip as possible; close, that is to say, both in the radial sense and in the axial sense. In the torch shown in the as-mentioned EP 93/202,778.2, for example, the water jacket is very close to the tip.

Alternatively, the water jacket may be located towards the outside of the torch, as the more or less outermost component of the torch. In either case, the manner, as described, of arranging the spigots may be utilised. When the water jacket is buried deep inside the torch, the water jacket is electrically live; when the water jacket lies towards the outside of the torch, the water jacket is non-live.

Fig 8 shows a diagram of the tip area of a torch 103 which has two water jackets: an inner water jacket 105 which lies deep inside the torch, and an outer water jacket 107 which lies towards the outside of the torch. The inner water jacket 105 is electrically live, while the outer water jacket 107 is non-live. The inner water jacket 105 is furnished with a water-feed passage 109 and a water-return passage 110, and the outer water jacket 107 is furnished with a waterfeed pipe 112 and a water-return pipe 114 (Fig 10), whereby the total of water passageways running along the conduit from the service station to the torch 103 is four.

Fig 9 is a continuation of Fig 8, and shows the handle of the torch 103. The non-live pipes 112,114 are brazed into suitable sockets in a block ring 116.

The block ring 116 defines a hollow chamber 118, and the pipe 114 opens into this chamber, whereby the chamber is full of water. On the right-hand side of the block ring 116, a pipe 11 4a communicates with the chamber 118. The other pipe 112 continues through the chamber 116. By this arrangement, the block ring 116 serves as a supplementary circulating cooling jacket of the non-live cooling system, and this supplementary jacket is suitably positioned, as shown, for cooling the torch handle 120 itself. The torch handle comprises a plastic moulding in two separate halves 123a,123b.

The various services are conveyed from the handle 120 to the front end of the torch 103 through the gooseneck 125. The welding wire 127 runs inside a plastic-covered cable 129, which lies inside the tube 130, and the argon, C02, or other gas is conveyed in the tube 130, around the cable 129.

The tube 130 is brazed into a tube 132, and the feed and return water passages 109,110 are formed as flats machined on the outer surface of tube 130, in the manner as described with reference to Fig 4.

The tubes 130,132 are both electrically live.

Surrounding the tube 132 is a sleeve 134 of plastic insulating material. A metal sleeve 136 in turn surrounds the plastic sleeve 134, and serves to protect the sleeve 134. The metal sleeve is electrically isolated from the tubes 130,132.

The welding wire 127 emerges from a copper tip 138, which in Fig 8 is in two pieces 138a,138b. The tip components 138a,138b are screwed into a body 140, which actually is a continuation of the tube 130.

It will be noted that the inner (live) water jacket 105 overlies the tip components; by extending so far forward, the inner water jacket can be very effective at keeping the tip cool-running, even under very heavy welding duty.

Holes 143 in the body 140 convey the gases around the tip 138. A deflector 145 of ceramic material ensures the gases do not jet directly onto the arc.

The outer (non-live) water jacket 107 lies outside a sleeve 147 of insulative material. The inner tube 149 of the outer water jacket is brazed onto the protective metal sleeve 136, and the outer tube 150 of the water jacket is brazed in turn onto the tube 149.

The outer tube 150 of the outer water jacket 107 defines a cylindrical surface for receiving a shroud 152. The shroud is a push-fit over the cylindrical surface, whereby the operator can slide the shroud off (to the left in Fig 8) to gain access to the tip 138 - for the purpose, for example, of replacing the components of the tip.

Flow directors, dividers, or baffles (not shown) placed inside the water jacket cause the water to circulate around the water jacket in an advantageous manner.

Fig 11 shows a cross-section of a block 156, in which are located two pipe-spigots 158,159. The spigots are arranged in a similar manner to that illustrated in Fig 3. (In Fig 9, it will be understood that the pipe spigots are present, but lie out of sight.) The spigots 158,159 are clamped into tapered holes in the block 156 by means of bolts 160 and draw-ring 163, in the manner as previously described.

Space inside the handle 120 is tight. and the block 156 is cut away, as shown in Fig 11, to provide room for the pipes 112,114 for the outer water jacket. Cutting away the block not only gives access room, but also lightens the weight of the block. The designer should see to it, as a general principle, that the components of the torch and the handle are as lightweight as possible. The draw-ring 163 similarly is cut away as shown in Fig 11.

Since the pipes 112,114 are non-live, whereas the block 156 is live, the designer should ensure that the sleeves of plastic insulation are fitted over such portions of the pipes which may be of metal, and which may contact the block.

The spigots 158,159 are connected to water hoses and electrical leads, as was described in relation to Fig 4. The conduit 165 (Fig 9) contains not only these two hoses/leads but also the pipes 112,114.

(The pipes 112,114 of course do not contain electrical leads.) Also within the conduit is the hosepipe 167 which surrounds the cable 129. This central hosepipe 167 is generally of greater diameter than the four waterconveying pipes, and its larger stiffness can affect the manipulability of the conduit and torch.

Therefore, it is advantageous to provide a swivel joint 169 (Fig 9) for connecting the central hosepipe 167 into the handle 120.

As shown in Fig 9, the inner tube 130 is formed, at its handle-end, with a cylindrical socket 170. A boss 172 is provided on the outside of the socket 170, which houses a grub-screw 173. A hollow stud 176 fits inside the socket 170; a groove in the stud receives the grub-screw 173, whereby the stud 176 may be clamped firmly into the socket 170.

A rotor 178 is clamped into the hosepipe 167, and engages the stud 176 in such a manner that the rotor is rotatable relative to the stud. A sleeve 180 is swaged to the stud 176, and retains the rotor to the stud, as shown in Fig 9.

When the conduit 165 is being called upon to twist relative to the handle 120, a degree of swivel of the central hosepipe 167 can, by means of the swiveljoint 169, take place. The stiffness of the central hosepipe was the largest contributor to the whole stiffness of the conduit; the other pipes and hoses in the conduit, being relatively small, have not much inherent stiffness.

It will be noted that the welding gas passes inside the hose 167 and inside the tube 130. Therefore, the swivel-joint 169 should be designed so as not to leak. It is recognised that the leakage of gas can be kept to a low enough value as to be insignificant when the swivel design is as shown. In the design as shown, no elastomeric seals are required, as the leakage path for gas passing out through the joint is tortuous enough, in itself, to give an adequate seal.

And even if some gas were to escape it would do little harm (apart from the cost of the lost gas). Such inconsequential leakage of gas may be contrasted with the consequence of a leakage of water from the water jackets, in that if water droplets get into the weld they can be very damaging.

In order to release the pipe spigots 158,159 from the block 156, for servicing of the torch, it is necessary for the draw-ring 163 to move to the right (Fig 9).

However, the boss 172 might interfere with such free movement of the draw-ring. As shown in Fig 11, the draw-ring is Shaped and not a complete ring, whereby the draw-ring can pss over the boss 172.

Fig 12 is a view, like Fig 11, of a manner of arranging the components inside the handle of the torch, where space is much confined. The block 174 is shaped in its upper area with suitable cut-outs to provide room for the pipes 112,114 supplying the outer water jacket The spigots 67 through which water is supplied to the inner water jacket are clamped into the block 174 by means of the drawring 176. The draw-ring is of complementary shape to the block 174. Three bolts 178 are used to force the draw-ring towards the block. At least one of the bolts should be threaded into the draw-ring, and have its head protruding on the remote side of the block, so that, when the bolt is slackened, a blow on the head tends to separate the draw-ring from the block. This is required because of the fit of the spigots into the block, which preferably is a self locking-taper fit. Knocking the draw-ring and the block apart releases the self-locking taper. Only one of the bolts need have this accessibility to be knocked: the others may, if more convenient, be threaded into the block, with the heads contacting the draw-ring.

In all the designs, the designer seeks to arrange the draw-ring, and the bolts, so that a balanced force can be applied to the pipe spigots when drawing the spigots into the respective blocks. In Fig 2, just one bolt was provided, Figs 5 and 11 show four bolts, and Fig 12 shows three bolts. When servicing the torches, when these bolts are released, the technician should take care to clamp the bolts down evenly -- obviously, it would be possible to damage the spigots by uneven tightening. However, again it may be noted that the draw-ring and the bolts are of steel, and are themselves highly resistant to being damaged: the contrast to other welding torches, where screw-threads are provided in small brass components again needs to be made.

Fig 19 shows another drawing of a torch handle, which illustrates how the components as described can be arranged to fit inside the handle. It will be noted that the block can be arranged to lie behind the area of the handle which houses the electrical trigger 180, whereby a slim, efficient, design can be maintained.

Of course, the designer of the torch which has both an inner (live) water jacket and a separate outer (non-live) water jacket is faced with the most demanding requirements - given that the conduit has to be lightly manipuiable and yet physically robust; and given also that the torch has to house two separate water systems and still be light and compact. The designs as illustrated show how these demanding requirements can be met.

The designs as described provide excellent cooling of the welding torch, particularly of the very tip of the torch, and especially so when the torch is fitted with two water jackets. The benefits of this excellent cooling are not just that the torch is cool and comfortable to hold, but rather, the cooler the tip of the torch, the less likely it is that the

In place of the block 156 of Fig 9, with its straightthrough passageways, the rather more complicated block 190 is used. On its left side, the-block 190 is formed with respective sockets for receiving two pipe-stubs 192,193, which are brazed into the sockets. The pipe-stubs align with the pipes 112,114, and are connected therewith by means of short lengths of rubber hose 195.

On its right side, the block 190 is formed with tapered connections 197 for receiving pipe-spigots 198,199 of the kind which have been previously described. The two pipe-spigots are coupled to respective flexible (plastic) water pipes which run along the length of the conduit and connect with the service station. The electrical connection to the torch is via flexible leads located inside the water pipes.

Water from the service station enters the block 190 through the spigot 198. From there, the water travels inwards along a drilling 200 (which is blanked off by means of a brazed-in plug 202), through the aligned hole in the metal tube 132, and into the water-feed passage 109.

From there, the water passes around the inner water jacket 105. The water returns along the passage 110. Upon returning to the block 190, the water then travels outwards along a drilling 204, and into the stub-pipe 193 and pipe 114.

From there, the water circulates around the outer water jacket 107. The water returns along the pipe 112, and reenters the block 190 through the stubpipe 192.

The direction of the water fiow may be reversed, i.e the water may be directed to flow first through the outer jacket.

Inside and within the block 190, the stub-pipe 192 is connected to the spigot 199. This connection is made by means of a series of cross-driilings, blanked-off passageways, and the like - the exact nature of which depends on the specific dimensions and layout of the actual block 190. The connection is shown in diagrammatic form in Fig 14 by the dotdash line 206.

It will be understood that the block 190 thus has two ports facing to the right, into which are inserted the two spigots 198,199; but the block has four ports facing to the left: namely the two sockets into which are inserted the two stub-pipes 192,193 for the outer jacket, and the two passages 109,110 for the inner jacket.

There are no straight-through water connections in the block 190 (as they were in Fig 7). The crossdrillings, hole-plugs, connecting passages, etc, inside the block 190 are such as to conduct the water first through the inner jacker and then through the outer jacket, in series. The skilled expert can, in a particular block, trace the passageways required to achieve the desired water-flow patterns.

The block 190 preferably is made of brass, and the plugs are brazed into the drilling as required: as a general rule in welding torches, the use of rubber seals should be avoided except where the sealed components have to be detachable.

In addition to the water-conveying passageways in the block 190, the designer must see to it that the block also contains holes for attaching the screws which pull the draw-ring 208, and the spigots, into the block, in the manner as previously described.

The block 190 is electrically live, being put in circuit with the wires inside the water pipes in the conduit by means of the tapered connections 197. The stub- pipes are electrically isolated from the block ring 116 (and from the outer water jacket) by means of the rubber hoses 195 (one of which is omitted in Fig 14).

Although there is a water connection between the two water jackets, there is little leakage of electrical current to the non-live water-jacket components, provided the water remains reasonably clean. Of course, the metal stub pipe cannot be connected directly to the block-ring 116.

Electric current is supplied to the block 190 through the spigots 198,199, which are connected to the flexible electrical current conductors as previously described.

For clarity of illustration, as will be understood by the skilled expert, the torches in the drawings are shown with their radial dimensions exaggerated. In fact, the designer should see to it, that the radial dimensions are as small as can be, bearing in mind the need for robustness.

Claims (13)

ims
1. CLAIM 1. Water-cooled welding torch apparatus, wherein cooling water or other fluid is supplied and conveyed from a service centre to the welding torch, wherein: the apparatus includes a relatively bulky block component, which has an interior passageway for the cooling fluid; the apparatus includes a relatively slender pipv spigot component, which has an interior passageway for the cooling fluid; one of those components has a socket, having an axis, and the other has a complementarily plug, which is axially engageable therein; the apparatus is so arranged that when the plug is operatively engaged in the socket the fluid passageway in the body communicates with the fluid passageway in the pipe-spigot; the apparatus includes a draw-ring component which is arranged. in the apparatus, to be axially moveable relative to the body component; the draw-ring component is in operative engagement with the pipe-spigot, to the extent that movement of the draw-ring component towards the block is effective to create a corresponding, in unison, movement of the spigot towards the block; the apparatus includes a screw-threaded fastener, which is manually tightenable, and which is arranged so that tightening of the screw-thread causes movement of the collar component axially towards the block, whereby the spigot is moved axially towards the block, and whereby the plug is urged into the socket.
2. CLAIM 2. Apparatus of claim 1, wherein the arrangement of the block, draw-ring, spigot, and screw-threaded fastener, is such that, when the fastener is slackened, a blow on the fastener is effective to drive the plug out of the socket.
3. CLAIM 3. Apparatus of claim 2, wherein the screw threaded fastener is threaded into the draw-ring component, and passes through a clearance hole in the block, and the bolt has a head which lies on a side of the block remote from the draw-ring.
4. CLAIM 4. Apparatus of claim 1, wherein the plug comprises a conically-tapered plug-form on the spigot, and the socket comprises a complementarily tapered socket in the block.
5. CLAIM 5. Apparatus of claim 4, wherein the taper is of such dimensions as to be self-locking.
6. CLAIM 6. Apparatus of claim 1, wherein the plug and the socket each are formed of metal, and the connection therebetween is provided with an elastomeric seal.
7. CLAIM 7. Water-cooled welding torch apparatus, wherein cooling water or other fluid is supplied and conveyed from a service centre to the welding torch, wherein: the apparatus includes a relatively bulky block component, which has an interior passageway for the cooling fluid; the apparatus includes two relatively slender pipes spigot components, each of which has a respective interior passageway for the cooling fluid; the block has two sockets, having an axis, into which a plug-portion of the pipe-spigot is axially engageable, the axes being parallel; the apparatus is so arranged that when the spigots are operatively engaged in the block the fluid passageways in the block communicate with the fluid passageways in the pipe-spigots; the said pipe-spigots are connected to respective flexible hoses or pipes. within which the cooling fluid is conveyed. one to, and the other from, the torch; when engaged in the block, each pipe-spigot is in electrical current-transmitting contact with the block; the apparatus includes electrical current-conveying means, for conveying electric current from the service station to the welding arc; the current conveying means includes two flexible leads, which are located one each respectively inside the two flexible hoses or pipes, and each lead is in electrical current-transmitting contact with the respective spigot.
8. CLAIM 8. Apparatus of claim 7, wherein the arrangement of the apparatus is such that the electrical current is split substantially evenly between the two flexible leads.
9. CLAIM 9. Apparatus of claim 7, wherein each of the said leads inside the respective hoses or pipes is in direct cooling contact with the water being conveyed in the respective hoses or pipes.
10. CLAIM 10. Apparatus of claim 7, wherein: the apparatus includes a draw-ring component which is arranged, in the apparatus, to be axially moveable relative to the body component; the draw-ring component is in operative engagement with the pipe-spigot, to the extent that movement of the draw-ring component towards the block is effective to create a corresponding, in unison, movement of the spigot towards the block; the apparatus includes a screw-threaded fastener, which is manualiy tightenable, and which is arranged so that tightening of the screw-thread causes movement of the collar component axially towards the block, whereby the spigot is moved axially towards the block, and whereby the plug is urged into the socket.
11. CLAIM 11. Apparatus of claim 7, wherein: the torch includes an insulative sleeve; the torch includes an inner, live, water jacket which is located inside the insulative sleeve, and which, in operation of the torch, is electrically live; the torch includes an outer, nor-live. water jacket which is located outside the insulative sleeve; and the said two pipe spigot components are so arranged in the apparatus as to convey water to and from the live water jacket.
12. CLAIM 12. Apparatus of claim 7, wherein: the torch includes an insulative sleeve; the torch includes an inner, live, water jacket which is located inside the insulative sleeve, and which, in operation of the torch, is electrically live; the torch includes an outer, non-live, water jacket which is located outside the insulative sleeve; the block is formed with first passage means for conveying water received from a first one of the said two pipe spigot components to and around a first one of the water jackets, and for receiving water returning from the said first water jacket; the block is formed with second passage means for conveying water received from the first water jacket to and around the second water jacket, and for receiving water returning from the second water jacket; and the block includes mean for conveying that returned water to the other one of the two pipe spigot components.
13. CLAIM 13. Apparatus of claim 7, wherein: the apparatus includes a flexible conduit for conveying the cooling water and other facilities from the service station to the welding torch, and the conduit is attached to a handle of the torch; the said block is fixed in the handle of the torch; the facilities which are conveyed in the conduit include welding wire, which is enclosed within tubing for conveying a weld-protecting gas; the block in the handle is formed with a cylindrical stator component; the conduit is formed with a cylindrical rotor component, to which is affixed the said tubing; and the arrangement of the rotor and the stator is such that the tubing is able to swivel with respect to the handle when the conduit is flexed.