AU2022265303A1 - Welding torch with a gas cooling function - Google Patents

Abstract

The invention relates to a welding torch for protective gas welding, comprising a rear connection to a media supply, which in any case comprises a supply of protective gas (S) and a supply line for a welding current. The welding torch also comprises a welding-side front end. The welding torch has an electrically conductive contact tip receptacle (2) which is electrically contacted in order to apply the welding current and in which a contact tip is releasably arranged that electrically contacts the contact tip receptacle (2) and is made of an electrically conductive material. The welding torch additionally has a gas distributor (4) for distributing and conducting the protective gas (S) in the direction of the front end of the welding torch. A front end of the contact tip is guided to the front end of the welding torch, and a rear section of the contact tip rests in a receiving opening of the contact tip receptacle (2). The rear section of the contact tip has a region (11) which tapers, in particular continuously, preferably conically, towards the rear end of the contact tip. The receiving opening in the contact tip receptacle (2) has a surface section (18) which is shaped so as to complement the tapering region (11) of the contact tip such that the tapering region (11) of the contact tip is in tight mechanical and electric contact with the surface section having the complementary shape. In order to better cool the contact tip, at least one channel-like recess (19) is molded into the receiving opening surface section having the complementary shape, said recess forming a gas conducting channel, which is connected to the supply of protective gas (S) from the media supply and to the gas distributor (4), between the contact tip receptacle (2) and the contact tip.

Description

Welding torch with gas cooling

The present invention relates to a welding torch for shielding gas welding having the features

of the generic part of patent claim 1.

Such welding torches are known from the prior art. They are used in particular in the field of

metal inert gas welding (MIG) and metal active gas welding (MAG), but can also be used in

tungsten inert gas welding (TIG). They can be used for both automated welding, where they are often mounted on welding robot systems, and in connection with manual welding, then in

conjunction with appropriate manual welding equipment.

The high temperatures generated at the welding point during the welding process are also transferred to the welding torch. The resulting input of thermal energy to the welding torch

must be dissipated by appropriate cooling, not least to protect and preserve the welding

torch and its individual parts. With the prior art, this is essentially done using two possible cooling media, liquid cooling or gas cooling. There are also systems that work with a mixture

of liquid and gas cooling media. If a gaseous medium is used for cooling, the shielding gas

used in the process, be it an inert gas or an active gas involved in the welding process, can be used for this purpose. As the supplied shielding gas flows around the elements of the

welding torch exposed to the heat, it absorbs the heat energy input there and dissipates it as

it flows away in the direction of the welding point. In the front area of the welding torch, this is done by the shielding gas flowing around the outer surface of the contact tip. In order to

increase the cooling effect here, particularly long contact tips are also used in a leading or

front section.

While a liquid cooling medium generally has the advantage of having a higher thermal

capacity and thus exhibits a better cooling effect, problems and disadvantages are also

associated with such a liquid cooling medium. On the one hand, in addition to the supply lines for welding current and shielding gas, supply and return lines for cooling liquid must be

provided as further components in the media supply system of the corresponding welding

device or automatic welding machine. Furthermore, there are limitations as to how close a liquid cooling medium inside the welding torch can be brought to the elements particularly

exposed to the heat, such as in particular the contact tip, which serves to contact a welding

electrode, such as a supplied welding wire, so that cooling cannot take place directly at the point where the heat input is particularly high. Finally, the supply of a further liquid, cooling medium to the area of the weld entails a risk that, in the event of a leak, this cooling medium may escape and thus cause damage and seam defects For example, escaping cooling water can cause the welding current to jump over electrically into the vicinity of the welding point; the workpiece being welded is usually rendered useless by contact with escaping cooling liquid such as water. By contrast, gas cooling, in particular cooling with the shielding gas used anyway, has the advantage that no further medium has to be supplied and that no seal has to be provided in the direction of the welding point since the shielding gas is intended to escape and flow there anyway, i.e. it is supplied to the welding point in any case. Accordingly, gas-cooled welding torches are also widely used in the prior art. Additional liquid cooling with which areas of the welding torch oriented further away from the welding point can be cooled is often used to enhance the cooling effect, so that additional energy can be dissipated and thus obviating the need for increasing the dimensions of the contact tip and other components of the welding torch at higher currents, which in turn would detract from the ergonomics and serviceability of the welding torch.

However, the problem with gas-cooled welding torches already explained above is always

that the cooling capacity of a cooling gas is lower due to the lower thermal capacity and thus

lower absorption of heat energy compared with a cooling liquid. Special efforts must therefore be made here to ensure sufficient cooling of the welding torch and in particular of

the components subject to high thermal loads, such as in particular the contact tip and also

the contact tip holder.

It is the object of the present invention to achieve an improvement in these efforts, in

particular to achieve improved cooling of the contact tip and the contact tip holder.

This object is achieved according to the present invention by a welding torch for gas-shielded welding having the features of claim 1. Advantageous embodiments of such a welding torch

according to the invention are proposed in dependent claims 2 to 14. A further solution to the

problem consists in a specially shaped contact tip suitable for use in the inventive welding torch as defined in claim 15.

According to the invention, a welding torch for gas-shielded welding has first a rear connection

to a media supply, which in any case comprises a supply of shielding gas and a supply of welding current. This media supply can also contain further media lines, for example a supply and a return line for a cooling liquid, if liquid cooling of the welding torch is additionally provided, or also a welding wire supply for a welding wire used as a consumable electrode. Furthermore, the welding torch according to the invention has a front end on the welding side. It has an electrically contacted and electrically conductive contact tip holderfor the supply of the welding current, in which a contact tip made of an electrically conductive material such as copper is detachably arranged. The contact tip is in electrically conductive contact with the contact tip holder, so that the supplied welding current is passed on to the contact tip via the contact tip holder.

The welding torch also has a gas distributor which serves to distribute the shielding gas

uniformly, in particular in circumferential direction, and, typically in interaction with a gas nozzle of the welding torch, to feed the shielding gas in the direction of the front end of the welding torch. The shielding gas then typically emerges at the front end of the welding torch

in the form of a shielding gas column surrounding the welding point.

A forward end of the contact tip arranged in the contact tip holder is directed towards the front end of the welding torch. A rear section of the contact tip rests in a receiving opening of

the contact tip holder. The rear part of the contact tip has a tapered section toward a rear end

of the contact tip, and the receiving opening in the contact tip holder has a flat section shaped complementarily to the tapered section of the contact tip. The section tapering

towards the rear end of the contact tip can be discontinuously tapered, e.g. stepped or

staggered. In one possible embodiment, it tapers continuously, e.g. parabolically or conically, in which case a conical shape is particularly preferred here. The tapered section of the

contact tip and the complementarily shaped surface section are shaped complementarily to

one another in such a way that the contact tip inserted in the receiving opening so that its tapered section is in close mechanical and electrical contact with the complementarily

shaped surface section of the receiving opening. If the contact tip is conically tapered in the

tapered section, the complementarily shaped surface section therefore has a taper formed complementarily to the taper of the tapered section of the contact tip.

In such welding torches, the contact tip is typically a wear part that has to be regularly

replaced. Even when making every effort to cool it, it is subject to high thermal loads and high electrical currents flow through it. It is therefore worn out after a number of welding cycles and must be replaced. This contact tip therefore lies detachably in the contact tip holder and is generally designed in such a way that it can be easily detached from the contact tip holder and replaced by a new contact tip inserted into the contact tip holder and detachably fixed there. In the inventive welding torch, the tapered shape of the tapered section of the rear part of the contact tip with which the contact tip lies in the receiving opening of the contact tip holder, provides on the one hand good mechanical and also electrical contact, since the contact tip can be pressed with its tapered section, which may e.g. be a cone, into the complementarily shaped, e.g. complementarily conical, receiving opening and can thus be brought into close contact. On the other hand, it facilitates in particular a release of the contact tip, since such a shape is less prone to blocking in the event of possible thermally induced deformation when the contact tip is to be released.

The special feature of the inventive welding torch now lies in the fact that at least one

channel-like recess is formed in the complementarily shaped surface section of the receiving

opening, through which a gas guide channel is formed between the contact tip holder and the contact tip, said channel being connected on the one hand to the supply of shielding gas

from the media supply and on the other hand to the gas distributor. During operation of the

welding torch, the supplied shielding gas is guided through this gas guide channel, which can be formed in particular exclusively by a channel-like opening formed in the complementarily

shaped surface section of the receiving opening, before it then flows further to the gas

distributor and is guided from there in the direction of the welding point, where it escapes to form the shielding gas column. Due to this measure, the shielding gas is in close contact with

the material of the contact tip in the rear section of the contact tip, which in the prior art is

usually firmly accommodated in the receiving opening of the contact tip holder and does not undergo any separate cooling there by the shielding gas, and can thus absorb and dissipate

thermal energy transferred to it. During the further forward flow, the shielding gas then also

passes over a front section of the contact tip, which is located in the direction of the front end of the welding torch, and also results in a cooling effect there. Accordingly, an improved

cooling effect of the gas-cooled contact tip is achieved with this inventive solution, since the

shielding gas serving as cooling medium passes over a further section of the axial extension of the contact tip, or it is in close contact with the shielding gas. The current transfer to the contact tip, which also takes place in the tapered section in which the at least one gas guide channel is formed, is not impaired by the interruption of the contact surface formed by the at least one gas guide channel, in particular because it can continue to be dimensioned sufficiently large. Outside the at least one gas guide channel, contact surfaces are formed which extend both in the longitudinal direction of the contact tip and in the circumferential direction of the contact tip and have sufficient surface area to ensure, on the one hand, mechanical retention and, on the other hand, in particular the transfer of the required welding current to the contact tip. It should be emphasised at this point that the gas guide channel formed is not limited either in its orientation with respect to a longitudinal axis or in its cross sectional shape. It can run in the longitudinal direction of the contact tip or at an angle to it, e.g. spirally. A branched form is also conceivable. It can also have an angular or rounded cross-section, e.g. rectangular, triangular, polygonal, (partially) circular or (partially) elliptical or similar form. The only thing that is important is that this gas guide channel directs the shielding gas flowing in from the gas supply towards the gas distributor in such a way that it causes cooling, in particular of the contact tip, but possibly also of other components past which it flows.

Advantageously, it is possible with the inventive welding torch that an electrical contacting of

the contact tip in the rear section takes place exclusively via a shell surface of the contact tip in the tapered section which rests on the complementarily shaped surface section of the

receiving opening. With a sufficiently large contact area, transmission of the welding current

is possible via the shell surface so that, in particular, a rear end face of the contact tip does not have to abut with or rest on an electrically conductive part. Such a concept does not,

however, preclude a current transfer in another section of the contact tip, e.g. in a connecting

section. In particular, according to a further advantageous embodiment, the inventive welding torch can have a rear end face of the contact tip arranged and fixed in the contact tip holder

that can be exposed without contact with another element. In particular, this also prevents

the rear end face of the contact tip from becoming stuck in use on such an otherwise required contact surface in the contact tip holder or on an adjacent part, which in turn makes

it more difficult, and in the worst case even prevents, the contact tip from being detached

from the welding torch in order to replace a worn contact tip with a new contact tip.

For a further improved cooling effect, it is possible that not only one gas guide channel is formed, but that at least two, in particular several, advantageously four, channel-like recesses formed in the complementarily shaped surface section of the receiving opening are present between the contact tip holder and the contact tip, such gas guide channels being connected in each case on the one hand to the supply of shielding gas from the media supply and on the other hand to the gas distributor. In this way, shielding gas is guided along the rear section of the contact tip over a larger contact area and contributes to the cooling of the contact tip and possibly other parts over which the shielding gas passes in this section.

The two or more gas guide channels formed in this way can be arranged in particular around

a circumference of the contact tip with uniform angular spacings. In this way, the cooling effect is distributed symmetrically around the circumference, and spaces of sufficient size are

left between the gas guide channels in which the contact tip with its tapered section is in close mechanical and, above all, electrical contact with the complementarily shaped surface section of the receiving opening for a reliable and sufficient transmission of the welding

current to the contact tip.

Advantageously, the gas guide channel(s) formed by the channel-like recess(es) is/are designed with a cross-section tapering towards the front end of the contact tip. This provides

improved guidance of the shielding gas used as cooling medium at this point with improved

flow dynamic properties.

In a further advantageous embodiment, the inventive welding torch can be provided with a

gas outlet bore which crosses the contact tip holder and opens into the at least one gas

guide channel and through which shielding gas can be transferred from the gas guide channel to an inner side of the gas distributor. If several gas guide channels are provided,

such a gas outlet bore is preferably provided for each of the gas guide channels, said gas

outlet bores being preferably arranged in the same axial positions, relative to a longitudinal axis of the welding torch or the contact tip, and distributed radially around the circumference.

During operation, the shielding gas can be introduced into the gas distributor via these gas

outlet bores after it has passed over the rear section of the contact tip and created a cooling effect there, from where it is passed on and distributed circumferentially, in the direction of

the front end of the welding torch.

The gas distributor of the inventive welding torch can in particular have gas passage openings distributed around a circumference of the gas distributor and crossing it for guiding the shielding gas from the inside of the gas distributor to an outer side of the gas distributor and for passing on the shielding gas to the front end of the welding torch, which, in particular, can also be arranged in a position which is the same as seen along the longitudinal axis, merely distributed radially along the circumference, in which case the gas outlet bore(s), as seen in the axial direction, is/are located closer to the front end of the gas distributor than the gas passage openings. With this measure, the shielding gas leaving the gas outlet opening(s) must first flow back in the gas distributor against the original direction of flow before it leaves through the gas passage openings and then flows away again in the opposite direction towards the front end of the welding torch. This measure means that the distance covered by the gas with a cooling effect is increased and to a better homogenisation of the shielding gas flow, and hence to an improved flow pattern of the shielding gas when it exits at the front end of the welding torch.

In addition to the gas outlet bore(s), one or more gas inlet bores may be provided which

cross the contact tip holder in a position further away from the front end of the welding torch in the axial direction compared to a position of the gas outlet bore(s) and open into the gas

guide channel(s) to transmit inflowing shielding gas into the gas guide channel(s). Such a

gas inlet bore or such gas inlet bores are preferably provided when a gas supply from the rear connection to the media supply through the welding torch takes place in a radially outer

position.

In the case of a central gas supply, e.g. in combination with a wire supply or wire guide hose, a different solution can be chosen here.

Advantageously, the inventive welding torch can be provided with a tapered section of the

contact tip that extends to its rear end. In such an embodiment, in particular, there is then no further, for example cylindrically shaped section of the contact tip which, if it rests in a

correspondingly shaped holder, can in turn lead to the problems of blocking or jamming

described above when a worn contact tip is to be removed from the contact tip holder and replaced with a new contact tip.

On the other hand, it may be possible, and is also employed in a currently preferred

embodiment, for the contact tip to have in its rear section a cylindrical section located in front of the tapered section, as seen from its front end. This has in particular a clearance from a wall of the receiving opening surrounding this section, so that an intermediate space is left and this cylindrical section cannot lead to jamming as described above due to deformation, in particular thermal deformation.

For detachable fixing in the contact tip holder, the contact tip of the inventive welding torch

can in particular have a thread in a fixing section adjoining the rear section in the direction of the front end. With this thread, the contact tip can be screwed tightly into a mating thread,

and thus be pressed into the contact tip holder, in particular with the tapered section of the

rear section pressed into the receiving opening of the contact tip holder. However, other types of fixing are also conceivable here, for example a type of bayonet connection.

In the inventive welding torch, in particular in one embodiment, the gas distributor can be

mounted on the contact tip holder and detachably connected to it, in particular by screws. In this case it is also possible and advantageous that the contact tip is detachably attached to

the gas distributor and projects with its rear section into the receiving opening of the contact

tip holder. In particular, if the contact tip has a thread in the fixing section as described above, it can be screwed into a female thread formed on the gas distributor. In particular, the

gas distributor is then closed by the contact tip screwed into it at a front end facing in the

direction of the front end of the welding torch, in particular in such a gas-tight manner that the shielding gas cannot escape there.

As an alternative to a design of the contact tip with a section tapering continuously, in

particular conically, towards its rear end, this section can also have a stepped taper as already mentioned above. Then, in particular, it is possible that the surface section of the

receiving opening provided in the contact tip holder, which is complementarily shaped to the

tapered section of the contact tip, is continuously tapered, such that at least one transverse channel is formed in at least one section in which the tapered section has a step. This

transverse channel extends essentially in the circumferential direction of the contact tip. In

such an embodiment, the tapered section is therefore not in contact continuously along the length of the tapered section in those sections where physical contact is made between the

tapered section and the holder, but at least one transverse channel is formed; a plurality of

transverse channels may also be formed. A further cooling effect can be achieved in these channels by the gas flowing through. This can be further improved if the at least one gas guide channel is circumferentially offset in sections where it opens into the transverse channel. The flowing gas is then forced to follow a flow path in the cross channel following the circumference of the contact tip.

The invention also proposes a specially designed contact tip made of an electrically

conductive material that can be used in a welding torch according to the invention disclosed here. In the installed position of the contact tip, this contact tip has a front section facing

towards a welding point, a fixing section adjoining the rear of the front section, and a rear

section adjoining the rear of the fixing section. With the fixing section, which can in particular have a thread, but in principle also other fixing structures, such as projecting protrusions of a

bayonet connection or the like, the contact tip can be fixed in a contact tip holder with corresponding mating structure. The rear section of the contact tip also serves to be fixed in the contact tip holder of a welding torch. This rear section of the inventive contact tip has a

section which tapers, in particular continuously, preferably conically, towards a rear end of

the contact tip and which, in the inventive welding torch, on the one hand serves to make electrical contact via a shell or circumferential surface of the contact tip in this area and, on

the other hand, is passed over by the shielding gas in the sections of the gas guide channels

which are formed by the recesses in the contact tip holder and serve to dissipate heat to the shielding gas. This contact tip is now characterised in that the ratio of an outer surface

formed by the contact tip in the tapered section to a radius of the contact tip in the rear

section where the tapered section with the larger radius begins, i.e. at a base of the tapered section, is at least 35 mm, preferably at least 40 mm, in particular at least 43 mm. The fact

that a ratio is provided here with a length specification in mm and is not dimensionless is due

to the fact that a ratio of an area to a length is specified. This value is particularly high compared with prior art contact tips having tapered areas in their rear sections. Known

contact tips of this type generally have a ratio of these values in the range of around 20 mm,

in exceptional cases up to 30 mm. This can be explained by the fact that the contact tips, which have to be replaced frequently as consumables and are typically made of the

comparatively expensive material copper, are manufactured in the rear area, which

contributes to the actual welding process in the prior art welding torches only by the welding current transmission taking place there, in a material-saving manner, i.e. short and thus with a small outer surface of a tapered section, in order to reduce the material costs in this area as far as possible. The surface area of this tapered section in relation to the radius at its base is essentially determined by the contact area required for sufficient current transmission. For the present invention, however, a part of the outer surface of the contact tip in this tapered section is deliberately excluded from the current transmission in favour of the formation of the gas guide channel(s), which serve(s) for heat dissipation. However, in order to maintain sufficient surface area for the current transmission on the one hand, and on the other hand to obtain a sufficient surface area in this section exposed in the gas guide channel(s) for heat dissipation to the shielding gas passing by there, the tapered section of the rear section of the contact tip is designed with an enlarged surface area and typically also manufactured longer. Ratios of the surface area of the tapered section to the radius at the base of the tapered section of at least 35 mm, preferably at least 40 mm, in particular at least 43 mm and more have therefore proved to be particularly suitable in order to now fulfil the double task of this tapered section, namely current transmission and provision of a heat-emitting surface.

The higher material input required for this can be more than compensated by the improved cooling in the inventive welding torch and by the longer service life of the contact tip achieved

as a result.

Furthermore, it is possible with the inventive welding torch or the inventive contact tip that the contact tip has a central bore for passing through and electrically contacting a welding wire

supplied via the media supply in a common and known manner for this type of contact tip.

A front end or front section of the inventive contact tip, also as a component of the inventive welding torch, with which it projects and protrudes in the direction of the front end of the

welding torch, can in principle have a different shape, for example cylindrical. In a current

embodiment variant, a likewise tapering, in particular conical, form is preferably chosen with the contact tip tapering in this section towards the front end of the welding torch.

Further advantages and features of the inventive welding torch described here and of the

inventive contact tip are explained once again to the skilled person in the following description of possible design variants of embodiment examples on the basis of the attached

figures. Where:

Figure 1 shows an exploded view of one embodiment of the front section of a welding torch according to the invention;

Figure 2 shows an inventive contact tip of the inventive welding torch from Figure 1;

Figure 3 shows a contact tip holder of the inventive welding torch from Figure 1 viewed at an angle from the front;

Figure 4 shows the contact tip holder from Figure 3 in a side view;

Figure 5 shows in a partially exploded side view the arrangement of the contact tip in the contact tip holder of the inventive welding torch from Figure 1;

Figure 6 shows the arrangement of the contact tip in the contact tip holder as in

Figure 5 in a partially exploded isometric view;

Figure 7 shows a gas distributor of the inventive welding torch from Figure 1;

Figure 8 shows the gas distributor from Figure 7 in a longitudinal sectional view;

Figure 9 shows a partially exploded view of front section of the inventive welding torch from Figure 1 with plotted flow lines to illustrate the flow of shielding gas; and

Figure 10 shows an enlarged view of a section from Figure 9 to illustrate the flow path of

the shielding gas in the area of the rear section of the contact tip and the gas distributor.

In the figures referenced below to explain the embodiment of an inventive welding torch

shown here, schematic representations of the essential elements of an inventive welding torch are shown with the same elements using the same reference numbers. The following

description is to be understood as a description of only one possible embodiment; further

embodiment variants of an inventive welding torch exist which are not explained in more detail here and which are readily apparent to the skilled person on the basis of the above

general description of the invention and on the basis of the following patent claims. The

following description of the embodiment example is therefore in particular not to be understood as limiting the scope and extent of the invention.

Figure 1 first shows an exploded view of the front section of a welding torch 1 according to the invention. The rear section of the welding torch 1 facing away from the welding point corresponds in its design to that of common and conventional welding torches and is therefore not shown or explained in more detail here. A media supply line is connected to a rear end of the rear section of the welding torch 1 via which welding media, in particular shielding gas, welding current and welding wire, possibly also cooling liquid, are supplied.

Further control and supply lines can also be connected there.

Figure 1 shows the structure of the front end of the welding torch 1 with a contact tip holder

2, a contact tip 3, a gas distributor 4 and a gas nozzle 5. In the assembled state of the

welding torch 1, the gas distributor 4 is mounted on the contact tip holder 2 and connected to it in a positionally fixed manner, in the embodiment shown by screws, and the contact tip 3 is

fixed to the gas distributor 4 and rests with a rear end in the contact tip holder 2. The gas nozzle 5 is placed over this arrangement and fixed to a torch body 6 of the welding torch 1, in this case by means of screws.

The individual components shown in Figure 1 are each shown again in isolation in Figures 2

to 4 and Figures 7 and 8.

Figure 2 shows the inventive contact tip 3. This has a front section 7 facing the welding point

during operation, a fixing section 8 adjoining the front section 7 in the direction of a rear end,

in which an external thread is formed in this embodiment, and a rear section 9 adjoining the fixing section 8. This rear section 9 is subdivided into a cylindrical section 10 directly

adjoining the fixing section 8 and a section 11 starting from this section 10 and tapering

conically towards the rear end. A bore 13 opens at a rear face end 12 which passes longitudinally through the contact tip and exits at its front end (see Figure 9). In the front

section 7, flat sections 14 are provided at radially opposed positions, which serve as a

contact surface for a tool for attaching or detaching the contact tip 3 to or from the gas distributor 4. According to the invention, the ratio of the outer surface formed in the tapered

section to a radius of the contact tip 3 in the rear section 9 where the tapered section 11 with

the larger radius begins, i.e. at a base B of the tapered section, is at least 35 mm, preferably at least 40 mm, in particular at least 43 mm. This ratio is indicated with a dimension in mm

because here an area (measured in mm 2 ) is set in relation to a distance, the radius

(measured in mm). The contact tip 3 is made from an electrically conductive material, in particular copper.

Figures 3 and 4 show the contact tip holder 2. This has an external (male) thread 15 which is interrupted by recesses 16 extending in axial direction and distributed uniformly around the circumference. From one front end face, a recess 17 is made in the contact tip holder 2,

which has circumferential flat sections 18 shaped conically and complementarily to the

conically tapered section 11 of the contact tip 3. Between these flat sections 18, recesses or cuts 19 extend radially outwardly into the material of the contact tip holder 2, which in this

embodiment extend in the longitudinal direction of the contact tip holder 2. In the area of the

recesses 16, gas inlet bores 20 pass through the wall of the contact tip holder 2 into the recess 17 extending into the interior thereof, which open into the recesses 19. Gas outlet

bores 21 pass through the wall of the contact tip holder 2 at positions of the recesses 19 closer to the front end of the contact tip holder 2 in axial direction.

Figures 5 and 6 show the seat of the rear section 9 of the contact tip 3 in the recess 17 of the

contact tip holder 2. In particular it can be seen there that when the contact tip 3 is properly

seated in the contact tip holder 2, the contact tip 3 rests with its conically tapered section 11 in close contact with the flat sections 18, so that mechanical contact is maintained there and

thus a firm seat of the contact tip 3 in the contact tip holder 2 is ensured. In the sections

where the recesses 19 are formed in the contact tip holder 2, gas guide channels are formed between the conical surface of the contact tip 3 in the section 11 and the contact tip holder 2.

The gas inlet bores 20 and the gas outlet bores 21 open into these gas guide channels.

During operation, the contact tip holder 2, which is also made of a conductive material, in particular copper, is electrically connected to the supply of the welding current, i.e. electrically

contacted. As a result, electrical contact is made between the contact tip 3 and the flat

sections 18 via the large-area contact of shell surface sections of the contact tip 3 in the conically tapered section 11, so that the contact tip 3 can be supplied with welding current

during operation. Due to the comparatively large surface area of the flat sections 18,

electrical contact is made over a large total area, so that a good electrical transition is ensured at this point. The face end 12 of the contact tip 3 is free here and does not come into

contact with the contact tip holder 2 or other parts.

Figures 7 and 8 show the gas distributor 4. Here it can be seen that it has an internal

(female) thread 22 and 23 in the area of each of its two longitudinal ends. The female thread 22 is used to screw the gas distributor 4 onto the male thread 15 of the contact tip holder 2,

which can be seen in Figure 3. The contact tip 3 with the male thread formed in the fixing section 8 is screwed into the female thread 23 and thus pressed with the rear section 9, in

particular with the conically tapered section 11, into the receiving opening 17 of the contact

tip holder 2, so that the close contact between the conically tapered section 11 and the surface section 18 described above is created and ensured (see also Fig. 9). It should be

emphasised here that the cylindrical section 10 is located in the rear section 9 of the contact

tip 3 at a distance from the inner wall of the contact tip holder 2 surrounding it, so that there is no contact between the contact tip holder 2 and the contact tip 3. The gas distributor 4 has

radially distributed gas passage openings 24 located in the same longitudinal position in a manner that is customary per se, which serve for the exit of shielding gas flowing through it.

The gas passage in the inventive welding torch is illustrated in Figures 9 and 10. Shielding

gas S supplied in the normal manner via the media supply, illustrated here by dashed lines,

first flows along the recesses 16 (see Figures 5 and 6) on the outside at the rear end of the contact tip holder 2 and then enters through the gas inlet openings 20 into the gas guide

channels formed by the recesses 19. In the process, the shielding gas flows along the rear

section 9 (see also Figures 5 and 6) of the contact tip 3, in particular along its conically shaped section 11, and provides a cooling effect here. The shielding gas S flows further

forward in the gas guide channels, which narrow in cross-section, and reaches the gas outlet

openings 21, where it leaves the inner area of the contact tip holder 2 and enters a space formed between the gas distributor 4 and the contact tip holder 2. It can be seen particularly

clearly in Figure 10 that the gas outlet openings 21, as seen in the longitudinal direction, are

in a position in front of the position of the gas passage openings 24 of the gas distributor 4, so that the shielding gas undergoes a deflection at this point and must first flow backwards

against the forward direction, before it emerges from the gas distributor 4 through the gas

passage openings 24 and continues to flow forward on the outside along the gas distributor 4 inside the gas nozzle 5, then flows along the front section 7 of the contact tip 3 and finally

leaves the gas nozzle 5 at the front end of the welding torch 1 facing the welding point as a

column surrounding the welding wire emerging there.

As already mentioned, the gas passage shown enlarged in Figure 10 results in a clearly and noticeably improved cooling effect of the contact tip 3. In particular, the contact tip 3 can be cooled much better in the inventive welding torch, resulting in an improved service life of the contact tip.

As shown in Figure 10, the shielding gas also has a cooling effect on the gas distributor 4 as

it passes as shown in Figure 10.

From the above description of the embodiment example, the advantages and features of the invention disclosed and claimed herein have once again been made clear. The following

claims define and designate the general scope of this invention.

Legend

1 Welding torch 2 Contact tip holder

3 Contact tip 4 Gas distributor

5 Gas nozzle 6 Torch body 7 Front section

8 Fixing section 9 Rear section

10 Cylindrical section 11 Conically tapered section 12 Face end

13 Bore

14 Flat section

15 Male thread

16 Recess 17 Recess / receiving opening

18 Flat section

19 Recess

20 Gas inlet bore 21 Gas outlet bore

22 Female thread

23 Female thread 24 Gas passage opening

B Base

S Shielding gas

Claims (15)

Claims

1. A welding torch (1) for gas-shielded welding with a rear connection to a media supply

comprising at least a supply of shielding gas (S) and a supply of welding current, and with a welding-side front end, said welding torch (1) having a contact tip holder (2)

which is electrically contacted and electrically conductive for the supply of welding

current, and a contact tip (3) made of an electrically conductive material arranged detachably arranged in and in electrically conductive contact with the contact tip holder

(2), and a gas distributor (4) for distributing and supplying the shielding gas (S) in the

direction of the front end of the welding torch (1), whereby one front end of the contact tip (3) runs to the front end of the welding torch (1) and a rear section (9) of the contact

tip (3) rests in a receiving opening (17) of the contact tip holder (2), wherein the rear section (9) of the contact tip (3) has a section (11) tapering, in particular continuously, preferably conically, towards a rear end (12) of the contact tip (3), and the receiving

opening (17) in the contact tip holder (2) has a flat section (18) shaped

complementarily to the tapered section (11) of the contact tip (3) in such a way that that the contact tip (3) with the tapered section (11) is in close mechanical and electrical

contact with the complementarily shaped flat section (18), characterised in that at

least one channel-like recess (19) formed in the complementarily shaped flat section (18) of the receiving opening (17), channel-like recess (19), through which a gas guide

channel is formed between the contact tip holder (2) and the contact tip (3) that is

connected on the one hand to the supply of shielding gas (S) from the media supply and on the other hand to the gas distributor (4).

2. Welding torch (1) according to Claim 1, characterised in that an electrical contacting of

the contact tip (3) in the rear section (9) takes place exclusively via a shell surface of the contact tip (3) in the tapered section (11) which rests on the complementarily

shaped flat section (18) of the receiving opening (17).

3. Welding torch (1) according to one of the previous claims, characterised in that at least two, in particular four, channel-like recesses (19) are present in each of the

complementarily shaped surface section (18) of the receiving opening (17) which each

form a gas guide channel between the contact tip holder (2) and the contact tip (3), each of which being connected on the one hand to the supply of shielding gas (S) from the media supply and on the other hand to the gas distributor (4).

4. Welding torch (1) according to Claim 3, characterised in that the recesses (19) forming the gas guide channels are arranged around a circumference of the contact tip (3) with

uniform angular spacings.

5. Welding torch (1) according to one of the previous claims, characterised in that the gas guide channel(s) formed by the channel-like recess(es) (19) have a tapering cross

section towards the front end of the contact tip (3).

6. Welding torch (1) according to one of the previous claims, characterised by a gas outlet bore (21) crossing the contact tip holder (2) that ends in at least one gas guide channel

for transmitting shielding gas (s) from the gas guide channel to one inner side of the

gas distributor (4).

7. Welding torch (1) according to Claim 6, characterised by gas passage openings (24)

distributed around a circumference of the gas distributor (4) and crossing it for guiding

the shielding gas (S) from the inside of the gas distributor (4) to an outer side of the gas distributor (4) for passing on the shielding gas (S) to the front end of the welding torch

(1), whereby the gas outlet bore (21), as seen in axial direction, is located closer to the

front end of the gas distributor (4) than the gas passage openings (24).

8. Welding torch (1) according to one of Claims 6 or 7, characterised by a gas inlet bore

(20) which crosses the contact tip holder (2) in a position further away from the front

end of the welding torch (1) in axial direction compared with a position of the gas outlet bore (21) and opens into the at least one gas guide channel to transmit inflowing

shielding gas (S) into the gas guide channel.

9. Welding torch (1) according to one of the previous claims, characterised in that the tapered section (11) of the contact tip (3) extends to a rear end of the contact tip (3).

10. Welding torch (1) according to one of the previous claims, characterised in that the

contact tip (3) has, in its rear section (9), a cylindrical section (10) located in front of the tapered section (11) as seen from its front end.

11. Welding torch (1) according to one of the previous claims, characterised in that the

contact tip (3) has a thread in a fixing section (8) adjoining the rear section (9) in the

direction of the front end.

12. Welding torch (1) according to one of the previous claims, characterised in that the gas

distributor (4) is mounted the contact tip holder (2) and is detachably connected to it, in

particular by means of screws.

13. Welding torch (1) according to one of Claim 12, characterised in that the contact tip (3)

is detachably attached to the gas distributor (4) and projects with its rear section (9)

into the receiving opening (17) of the contact tip holder (2).

14. Welding torch (1) according to one of the previous claims, characterised in that the

tapered section (11) towards the rear end (12) of the contact tip (3) is formed in a

stepped manner, and in that the flat section (18) of the receiving opening (17) provided in the contact tip holder (2), said flat section (18) being complementary in shape to the

tapering portion (11) of the contact tip (3), is formed in a continuously tapering manner,

such that at least one transverse channel is formed in at least one section where the tapered section (11) has a step.

15. Contact tip (3) made from an electrically conductive material for a welding torch (1)

according to one of the preceding claims, having a front section (7) facing towards a welding point in the installed position of the contact tip, a fixing section (8) adjoining the

rear of the front section (7), and a rear section (9) adjoining the rear of the fixing

section (8), wherein the rear section (9) has a tapered shape, in particular continuously, preferably conically, towards a rear end (12) of the contact tip (3), characterised in that

the ratio of an outer surface formed by the contact tip (3) in the tapered section (11) to

a radius of the contact tip in the rear section (9) where the tapered section (11) with the larger radius adjoins is at least 35 mm, preferably at least 40 mm, in particular at least

43 mm.

WO WO2022/229166 2022/229166 PCT/EP2022/061019 PCT/EP2022/061019 1/4

1 6 2

If 3 5

20 21

4

Fig. Fig. 11

2

14 3 18 17

18 19 8 20 10 21 B

11 7 16

12 21 13 9

Fig. 22 Fig. 16 15

Fig. Fig. 33

WO2022/229166 WO 2022/229166 PCT/EP2022/061019 PCT/EP2022/061019 2/4 2/4

2

15

21

20 16 Fig. Fig. 33

2 21 20 16 3 19 10 18

9 11

8 15

Fig. Fig. 55

WO2022/229166 WO 2022/229166 PCT/EP2022/061019 PCT/EP2022/061019 3/4 3/4

3

21

20 9 2

16

8 10 11 17 Fig. Fig. 66

4

4 22 24 23

23

24

Fig. Fig. 77 Fig. Fig. 88

WO 2022/229166 PCT/EP2022/061019 4/4 4/4

1

6

2 4

24 18

3 5

S

19 11 Fig. Fig. 99

13 S

11

2

20 19 24 21 S Fig. 10 Fig. 10