IES80537B2 - Device for the holding and discharge of liquid working substances in particular solders for the production and release of joints and for the coating of articles - Google Patents

Abstract

Known devices for producing component joints or surface coatings, comprise a heating device with a working part (1) which can heat a working substance until it reaches a plastic or fused state. In order to ensure that the working substance is discharged in a metered dose and that the working substance can be removed, for example in a desoldering process, the invention provides that said working part (1) has a working section (2) which is configured as a tool for applying working substances and consists at least partly of a porous material, especially metallic sintered material, sintered plastic or porous ceramic material. Said porous material then serves as a storage medium for removing and applying the working substance.

Description

Device for the holding and discharge of liquid working substances, in particular solders, for the production and release of joints, and for the coating of articles Description The invention relates to a device for producing joints between components and/or for coating surfaces, comprising a heating device with a working part by means of which a working substance 1Q required for producing the joint or the coating can be heated and can be brought into a plastic or molten state, the working part comprising means for the application of working substance and means for the removal of working substance.

A device of the generic type is known (DE-OS 1 752 081) which is designed as a soldering iron and is provided with a soldering bit, which is used for the production of soldered joints or coatings for components. This soldering bit should also be suitable for unsoldering two components which have been soldered to one another and therefore forms the working part of the device designed as a soldering iron. To enable this soldering bit of the known soldering iron to be used both for the soldering of components and for the unsoldering of two components which have been soldered to one another, the soldering bit is surrounded by a wire mesh which absorbs the solder. This wire mesh is substantially tubular in design and consists, for example, of a copper mesh which is to resemble a shielding mesh of a coaxial cable or of a mesh of thin steel wire. The wire mesh is pushed over the soldering bit for assembly purposes and is fastened on the soldering bit by a locking ring. The thermal· coupling between the wire mesh and the soldering bit is improved by this locking so the wire mesh has the temperature of the soldering bit. This wire mesh should permit simple unsoldering of two components. If the wire mesh S 80 5 37 is completely soaked with solder after unsoldering of several soldering positions, the solder which is kept liquid in the wire mesh can be shaken off by a centrifugal movement so the wire mesh is capable of holding further solder again.

For soldering two components, the wire mesh has to be pushed on the soldering bit until the end of the soldering bit is freely accessible. This means that the known soldering bit can be used only to a variable limited extent for soldering and unsoldering purposes. In particular, either cooling, i.e. disconnection of the soldering iron for displacement of the wire mesh, is necessary or special precautions have to be taken to prevent injury to operating personnel on the heated soldering bit. Furthermore, the wire mesh cannot be used for an unlimited period as the wire mesh frequently becomes brittle after a few days owing to the permanent heating effect of the soldering bit and has to be replaced by a new wire mesh. In addition, the wire mesh can only be displaced with difficulty or not at all on the soldering bit after absorption of solder during the unsoldering process once the soldering iron has cooled because . the solder also bonds to the soldering bit at least in certain regions. Therefore, reliable displacement on the soldering bit is only ensured when the soldering bit is heated.

The known device can also be used exclusively as a soldering iron for the soldering and unsoldering of components and for the surface coating of components with solder.

It is accordingly an object of the invention to design a device of the generic type such that an appropriate working substance can be applied to a component as a coating by heating and a joint between two components can be reliably produced. A metered discharge of the working substance should also be ensured and removal of the working substance should also be ensured, for example during an unsoldering process.

According to the invention, the object is achieved in that the working part comprises a working portion which is designed as a tool for the application of working substance and consists at least in part of a porous material, in particular metallic sintered material, sintered plastics material or of porous ceramic material which is used as a storage medium for the removal and for the application of the working substance.

With the design according to the invention, a device is provided with which joints between components or coatings on component surfaces can be reliably produced in the simplest manner. Owing to the use of a porous material, in particular a metallic sintered material, sintered plastics material or a porous ceramic material, the working portion of the working part of the device according to the invention has a storage function based on the capillary .action, and wettability of the porous materials mentioned by way of example. Depending on the working temperature, a variety of working substances can be absorbed and discharged again by the working portion.

It is thus proposed that the device according to the invention be used, for example, for the metered application and aspiration of adhesives of the type used in conjunction with hot-melt adhesive guns.

Depending on the selected working temperature and the design of the heating element, moreover, any soldering work such as hard soldering and soft soldering can also be carried out. Owing to the capillary action of the porous material of the working portion, the aspiration, for example, of a soldering position is ensured, in that the soldering position is simply heated to working temperature via the working portion, and the solder is therefore automatically aspirated from the soldering position owing to the capillary action of the pores in the Depending on the working substance used, an additional suction function may be required, particularly if the capillary action alone is not adequate for aspiration. In these cases, the working portion of the working part can be coupled to an appropriate suction device so an additional suction effect is exerted on the working part and the working substance sucked through the working part.

For the application of working substances to surfaces of workpieces or generally to articles of any type, the working part is initially filled with the appropriate working substance at the appropriate working temperature so, during contact between the working part and the corresponding surface, this working substance is discharged intentionally and in a metered form onto this surface. It is therefore also proposed that graphic structures be applied to these articles or workpieces. Working parts of different shapes can be coupled to the heating device for different tasks so different joints and surface coatings can be produced reliably.

For the exchangeable fastening of the working part on the heating device, the heating device can have a fitting shank with which the working part can be fastened in a locking manner in a corresponding receiving bore in the heating device. An extremely good thermal coupling between the working part and the actual heating device is thus ensured so a relatively constant working temperature of the working part is ensured even when using a correspondingly’ temperatureregulated heating system. The working part can also be provided with a fitting thread by means of which it can be screwed to the heating device. Extremely simple fitting of the working part on the heating device is thus permitted. A catch connection or locking connection can also be provided instead of the fitting thread, a secure thermal coupling of the working part to the heating device thus also being permitted.

Rapid heating of the working part or of the working portion is ensured by the embodiment of the invention acem-riing to claim 2 because the heating energy is discharged directly in the working part or its working portion by the heating device integrated in the working part and/or working portion. Alternatively, for direct integration of the heating device in the working portion, according to claim 2, for heating the working portion, a heating rod can be provided as heating device which is at least partially surrounded by the working portion formed from porous material. with this design according to the invention, the thermal energy is also discharged directly onto the working portion. It is also proposed that the heating rod which can consist of a highly thermally conductive material which can be wetted with working substance forms a part of the surface of the working portion so, for exan^le, during an unsoldering process, the thermal ehergy required for melting on the solder is. dischargeable directly on the solder to be removed and significantly shorter heating times can therefore be achieved for the solder.

The feed and/or aspiration ducts provided according to claim 3 allow appropriate continuous use on the one hand for producing joints and surface coatings and on the other hand for the aspiration of working substances during continuous operation. The feed and aspiration ducts can be connected to corresponding holding chambers and feed chambers of the device so working substance can be fed temporarily to the working part, as required. Furthermore, the coupling of the feed and aspiration duct to a corresponding aspiration system of the device significantly increases the holding capacity for the aspiration of excess working substance so constant aspiration of working substances is also ensured during continuous operation.

The feed and/or aspiration duct can be arranged inside the working portion of the working part and can also end within the working part or working portion. During the application of working substance, for example, this reliably prevents the working substance from continuing to drip after the actual working process. If the working part is used, for example, as a soldering bit and pure soldering tin is supplied without flux co this soldering bit via the feed duct, the feed duct can also penetrate right through the working part and have an outlet orifice at the outer end of the soldering bit, for example, in particular for the metering of relatively large quantities of soldering tin for a soldering position. The same applies if this duct is designed as an aspiration duct and relatively large quantities of solder are to be aspirated. Whether the feed and/or aspiration duct ends within the working part or the working part is completely penetrated depends substantially on the working substance used and its flow properties.

The embodiments according to claim 4 also ensure reliable feeding of working substances for a large number of working processes. The cavity of the working part acts as an intermediate reservoir which can be filled again at any time from an appropriate holding chamber as necessary via the feed duct. The cavity can also act as a holding reservoir during the aspiration of working substances, and the working substance can be used again for example for the subsequent production of joints between components or of surface coatings, providing it is still free from impurities after aspiration. A considerable saving in working substance is thus achieved.

The casing for the working part proposed according to claim 5 permits, on the one hand, the targeted feeding of flux and reliable aspiration of the working substance. With appropriate design of the casing, the casing together with the working part or the working portion can form a type of feed and/or aspiration duct so, in particular, an aspiration effect can easily be increased as desired by application of a vacuum or a reduced pressure to the working part. The targeted feeding of working substance in relatively large quantities can also be achieved reliably, and the working substance can be fed from a corresponding storage chamber to the working part, for example from its rear.

The device according to the invention can be designed as a soldering iron of which the working part forms a soldering bit made of porous material. Soldering positions and surface coatings can very easily be produced from solder using this device according to the invention. Furthermore, solder and also flux can very easily be aspirated from a soldering position for unsoldering two components. By appropriate choice of the pore size of the porous material, furthermore, a metered supply of solder to the soldering position is ensured because this solder only passes onto the soldering position until an adequate quantity is present. The pronounced capillary action of the pores of the porous material ensure that excess solder can never pass onto the soldering position.

It is also proposed that the working part be designed in the manner of a cap and be pushed onto an existing working element, for example onto a soldering bit of a soldering iron. With this design, a conventional soldering iron can easily be equipped with the working part according to the invention at a later stage. This may be advantageous, in particular in the case of hand soldering tools with already integrated feed and/or aspiration ducts in the soldering hit. particularly if its soldering bit itself cannot be exchanged for a soldering bit made of porous material. The working part pushed onto the pyj at.-ing anIderi ng bit will prevent unintentional continued dripping of the soldering bit, in particular during the soldering of components, so the reliability of operation of an existing hand soldering tool is considerably increased.

The device according the invention can be designed as a hotmelt adhesive gun of which the working part forms a bonding bit made of porous material. The hot-melt adhesives used with hot-melt adhesive guns, like solder, have the property that they can be liquefied or can at least be converted inf-o a plastic state when heated to a specific working temperature. Hot-melt adhesive positions can also be produced easily using the device according to the invention. Excess hot-melt adhesive can also be removed from a bonding position owing to the capillary action and/or by additional application of a vacuum or reduced pressure to the working part.

The working portion can also be constructed from layers of porous material having different porosity, the holding capacity of the working portion for various working substances or a specific working substance can be improved. Thus, for example, a lower porosity can be provided in the surface regions of the working portion to ensure adequate capillary action and greater porosity in the inner regions of the working portion to increase the holding capacity. To achieve this different porosity, different porous materials can be provided for the working portion of the working part or also for the entire working part. This region of different porosity can also be selected such that a region of the working portion can be formed from a porous material provided for holding working substance, while a different region of the working portion is formed from a porous material which is incapable of holding working substance but is permeable to air. The further advantageous functional properties of a working portion of this design which can be achieved in this way are described with reference to a soldering bit as an example. Thus, for example, a central core portion of the soldering bit which is freely accessible from the exterior at its free end can be formed from sintered bronze. This core portion is intended to hold and to discharge solder. The core portion is also surrounded by a covering formed, for example, from ceramic porous material from which the free end of the core portion projects axially.

These coverings can be surrounded by a casing, as already mentioned with reference to claim 5. A soldering bit of this design allows solder to be aspirated and also discharged on the one hand. On the other hand, the annular duct formed by the ceramic material or the covering and its casing and surrounding the core portion can act, for example, as an aspiration duct for the unhealthy fumes frequently formed during the soldering process owing to its permeability to air, in that it is coupled to an appropriate aspiration device. As the ceramic material is not wettable with solder, solder cannot accidentally penetrate it, so the annular duct always remains permeable for aspiring the fumes.

Surface modulation of the porous materials can be provided for the various applications, in particular, for example, platinum coatings can be provided in the case of ceramic material or metallic coatings in the case of plastic materials if these porous materials are provided, for example, for use of the working part as a soldering bit. The adhesion of the working substance, for example of the solder, in the pores of the porous material is increased by this surface modulation of the porous materials so the ' capillary action for holding of the working substance is also improved- Any materials which increase the wettability of the internal surface of the porous material of the working part for the respective application can be used as coating, materials, nickel, special steel, chromium, steel, tin, silver being mentioned as examples for use of the working part as a soldering bit.

Materials such as sintered bronze and comparable materials can be provided for producing a soldering bit. A soldering bit of this type made of porous sintered bronze is eminently suitable, for example, for use during soft soldering. Surface modulation can also be provided to increase the service life of such a soldering bit so oxidation processes are prevented or at least substantially reduced.

The design of the device according to the invention provides a device which is extremely versatile. For example, the device according to the invention, as already mentioned above, can be used as a hot-melt adhesive gun for the metered application of hot-melt adhesives and also for the aspiration thereof. Hard soldering as well as soft soldering are permitted, depending on the working temperature selected, a metered supply of solder and also aspiration of the solder hue also of unhealthy fumee being easily and reliably achievable during a soldering process.

JO Therefore, any work involving working substances during which the working substance can be brought into a type of molten state by attainment of a specific working temperature can be carried out using the device according to the invention.

Metered feeding of the working substance to the desired working position can be achieved reliably in this molten state with the working part according to the invention made of porous material.

The above-mentioned applications are mentioned merely by way of example as other fields of application are also conceivable 2θ in which the working substance can be converted into a molten state at a specific working temperature and can therefore be processed using the device according to the invention. The fields of application of the device according to the invention may be restricted by the maximum working temperatures attainable.

As a further advantage, simple handling of the device according to the invention is ensured as single-handed operation is reliably permitted. The operating personnel therefore always have one hand free for handling the components to be processed, to enable these components to be positioned correctly.

The. invention is described in more detail hereinafter with reference to the drawings.

Figure 1 shows a conical working part according to the invention with connecting thread.

Figure 2 shows the working part from Figure 1 with an additional cladding.

Figure 3 shows a working part according to the invention with fitting shank and combined feed and aspiration duct.

Figure 4 shows a working part according to the invention with additional fitting shank and a cavity with feed bore.

Figures 5 to 9 show various geometric embodiments of the working part according to the invention.

Figure 10 shows the working part from Figure 4 in conjunction with a heating device.

Figure 11 shows a further method of fitting the working part from Figure 4 on a heating element.

Figure 12 shows a working element which is designed in the form of a cap pushed onto an existing soldering bit.

Figure 13 shows a working part with integrated heating device.

Figure 14 shows a working part consisting of various porous materials.

Figure 15 shows a partial section of a working part with integrated heating rod.

The embodiments mentioned hereinafter essentially relate to a working part designed as a soldering bit of a soldering iron or hand-held soldering tool. The details of these embodiments are also applicable . to the above-mentioned other examples of application and should not be understood as a restriction to the subject of the invention.

Figure 1 therefore shows a working part which is designed as a soldering bit 1 and as a substantially conically designed working portion 2. The working portion 2 is rounded at its lower end 3. At its opposing upper end 4, the soldering bit 1 is provided with a fitting thread 5 via which the soldering bit 1 can be thermally and mechanically coupled to a corresponding heating device of a soldering iron.

The soldering iron 1 consists of a porous material such as a metallic sintered material, sintered plastics material or of a porous ceramic material. Pore sizes with an average diameter d of about 20 pm to about 1300 pm or a porosity ε of about 26% to about 65% are. provided for the soldering application, depending on the choice of porous material. Depending on the type of solder to be used in the outer regions of the soldering bit, this porosity can be higher or lower than in the interior of the soldering bit to ensure optimum capillary action and also an optimum holding capacity of the soldering bit for solder but also for flux.

It is important for the material, from which the soldering bit 1 is formed, to be a porous material. Owing to the porosity of the material of the soldering bit 1, solder, flux and heat can be supplied in a finely metered form to a soldering position via the soldering bit 1. Sintered bronze, special steel, brass, aluminium, titanium or iron are mentioned as examples of types of material for the production of such a soldering bit. This list should not be considered as a restriction to these materials.

The soldering bit 1 itself forms a reservoir for solder and/or flux and therefore has a storage function. The soldering bit 1 has capillary action owing to the use of said porous materials, so the holding capacity of the soldering bit 1 itself for flux and/or solder is achieved. The surface of the porous material can be modified, particularly if plastics material or ceramics are used, in order to improve this holding capacity. Thus, when using plastics materials or ceramics, a metallic surface coating for the pores of these materials is provided so improved adhesion, in particular of molten solder in the pores of the material is created and the capillary action in the soldering bit 1 for holding the solder thus improved. Nickel, special steel,- chromium, steel, tin and silver are mentioned as nonlimiting examples of coating materials for surface modulation.

When sintered metals such as sintered bronze are used, the service life of the soldering bit is also increased, for example, by such surface modulation as oxidation processes are prevented or at least substantially reduced, for example in the case of sintered bronze.

Figure 2 shows a second embodiment of the soldering bit 1 from Figure 1 which is provided with a casing 6 over a proportion of its total length. This casing 6 prevents uncontrolled escape of solder over substantially the entire bit geometry, particularly if the porous material has a relatively great pore size, so targeted application of solder to the desired soldering position without uncontrolled droplet formation is ensured. The casing 6 can also be coupled to an aspiration device directly connected thereto (not shown in the drawing) so the soldering bit together with the casing 6 forms a type of aspiration duct. This aspiration duct can obviously also serve as a feed duct for solder and/or flux in that an additional coupling to an appropriate feed system is provided. With the proposed casing 6, precise focusing on the working position of the corresponding component or the corresponding components is achieved.

Figure 3 shows a soldering bit 7 according to the invention having a substantially conical working portion 8 which is fitted securely in a fitting portion 9. With appropriate design of a heating device for a soldering iron, the fitting portion 9 serves to hold the soldering bit 7 in this heating device. In addition to this fitting portion 9, a fitting thread 10 is provided at the upper end of the fitting portion 9 so the soldering bit 7 can be coupled thermally and mechanically to differently designed heating devices.

A combined feed and aspiration duct 11 is provided inside the working portion 8. This feed and aspiration duct 11 ends inside the working portion 8 so it does not have an opening to the exterior. This reliably prevents solder from being able to issue uncontrollably from this duct, for example during the supply of solder through the feed and aspiration duct 11, because it is closed by the porous material at its lower end. Depending on the solder used, this feed and/or aspiration duct 11 can also have a discharge or intake orifice to enable, for example, relatively large quantities of solder to be delivered in a metered form. It will be appreciated that it is also possible to provide several ducts in the working part or the soldering bit 7, one duct being provided as a feed duct for solder, one for the feeding of flux and one as an aspiration duct for flux and/or solder.

The range of applications of the soldering bit 7 is considerably increased by this feed and aspiration duct 11 because additional solder can be fed to the working portion 8 if necessary, and the number of soldering points to be produced, not just the holding capacity of the working portion 8 itself is limited. Solder is fed independently of the actual soldering process after production of several soldering positions only when the supply of solder stored in the soldering bit itself or in its working portion 8 is almost exhausted.

Furthermore, it is also proposed for the embodiment of the soldering bit 7 that a corresponding casing of the type shown in the embodiment according to Figure 2 be provided so, in particular, targeted aspiration of solder and flux from a soldering position can be achieved. Owing to the additional casing, the suction via the feed and aspiration duct targeted on the lower end of the soldering bit 7 is restricted so disturbances due to the possible intake of ambient air via the conical surface of the soldering bit 7 are reliably prevented.

Figure 4 shows an embodiment of a soldering bit 12 with a fitting portion 13, a fitting thread 14 and the working portion 15. The working portion 15 also consists of a porous material, a cavity 16 which acts as a reservoir, for example for solder, being provided inside the working portion 15. This cavity 16 has an inlet bore 17 in the region of its upper end, through which the cavity 16 can be refilled if necessary. It is also proposed that this cavity 16 be coupled to the feed and aspiration duct 11 from Figure 3. However, the intake bore 17 is not provided in this case.

Figures 5 to 9 show various geometric designs of a working part according to the invention, in particular a soldering bit.

Thus, Figure 5 shows an embodiment in which the soldering bit 18 has a chisel-shaped working portion 19.

Figure 6, on the other hand, shows a soldering bit 20 of which the working portion 21 is designed as an elliptical end face.

The soldering bit 22 shown in Figure 7 has a screwdriver-shaped working portion 23 with which, for example, soldering can be carried out over large areas.

Soldering bits 24 having a tapered working portion 25, as shown in Figure 8, are also provided for fine soldering. Extremely fine soldering positions can be produced with soldering bits 24 of this design.

Figure 9 shows a soldering bit 26 having a diamond-shaped working portion 27 which also tapers at one end. This soldering bit 26 with its diamond-shaped working portion is suitable, on the one hand, for extremely fine soldering processes and also for producing larger soldering positions owing to the flat lateral parts of the working portion 27.

Figure 10 shows the soldering bit 12 which is screwed securely and exchangeably into, a corresponding female thread 28 of a heating device 29 by its fitting thread 13. The heating device 29 is part of a soldering iron not shown in the drawing. This threaded connection permits reliable transfer of heat between the soldering bit 12 and the heating device 29.

Figure 11 shows a further embodiment of a heating device 29' of a conventional commercial hand soldering tool (not shown in the drawing).

This heating device 29 has a substantially transversely extending through-bore 30 in which the soldering bit 12 can be correspondingly inserted with its fitting portion 13. For fixing the soldering bit 12 in the through-bore 30 there is provided a locking screw 31 which extends coaxially to the heating device 29 and is screwed therein at the end face and presses in a locking manner against the fitting portion 13 of the soldering bit 12.

As shown in Figure 11, for simplified handling of the soldering bit 12 in the heating device 29, the soldering bit 12 is arranged with its longitudinal central axis 32 inclined slightly to a plane extending perpendicularly to the longitudinal central axis 33 of the heating device 29.

Figure 12 shows a further embodiment of a working part 34 according to the invention which is cap-like in design. In the present embodiment, the working part 34 is pushed in a locking and exchangeable manner onto an existing soldering bit 35 of a hand soldering tool 36. The hand soldering tool 36 has a feed duct 37 for solder which connects the soldering bit 35 to a storage chamber 38 serving to hold, solder 39.

The storage chamber 38 is surrounded by a heating device 40 almost over its entire length so the solder 39 in the storage chamber 38 can always be kept in the molten state during operation.

With this embodiment of the hand soldering tool 36, the soldering bit 35 contains a feed duct 41 which is connected via a corresponding connecting tube 42 to an associated storage chamber (not shown in the drawing) for flux.

For the aspiration of excess solder and/or flux from an existing soldering position, the soldering bit 35 has an aspiration duct which is connected to an aspiration device (not shown in the drawing) via an appropriate connecting tube 44.

Extremely varied use of the hand soldering tool 36 can be achieved with the hand soldering tool 36 in conjunction with the porous working part 34 according to the invention.

Metered feeding of solder and flux to soldered joints to be produced can therefore be achieved, and well over one hundred •soldering positions· can be appropriately produced in one working process owing to the existence of storage chambers.

The working part 34 according to the invention ensures reliable metering both of solder and of flux, and the following of solder or flux can take place not continuously but at various time intervals so dripping of flux or solder is reliably prevented.

This hand soldering tool 36 in conjunction with the working part 34 according to the invention can also very easily be used for the aspiration of excess solder and also flux owing to the existence of the aspiration device.

Figure· 13 shows an embodiment of a working part 45 with a working portion 46 which is substantially conical in design and has a rounded tip of the cone 47. At its end remote from the tip of the cone 47, the working part 45 .is provided with a fitting shank 48 of substantially cylindrical design by means of which the working part 45 can be fitted in a locking and exchangeable manner on a handle equipped with appropriate fitting means (not shown in the drawing). In the interior of the working part 45 there is provided a heating device 49 in the form, for example, of heating wires or heating coils which has a cylindrical portion 50 and a conical portion 51 and is adapted to the shaping of the working part 45 with its working portion 46. The heating device 49 extends at least into the axial centre of the working portion 46 so extremely rapid heating of the working portion 46 by the heating device 49 is ensured. With the present embodiment, the heating device 49 is open at the bottom so working substance can be supplied in the respectively required quantities through the feed orifice 52 formed by the heating device 49 to the working portion 46. In the cavity 53 formed by the heating device 49 there can also be provided temperature probes (not shown in the drawing) by means of which the temperature of the heating device 49 and therefore the temperature of the working part 49 can be continuously measured and can accordingly be kept substantially constantly at the desired temperature via a separate controller. For supplying energy to the heating device 49, the working part 45 has, at the top end of its cylindrical portion 5 0, two contact pins 5 4 and 55 by means of which the heating device 49 can be supplied with the necessary electric power through a corresponding power source which is arranged externally or integrated in the handle. The contact pins 5 4, 55 can be electrically coupled to appropriate contact elements of the handle.

Figure 15 shows a soldering bit 68 according to the invention which -also has a substantially conical working portion 69 which is fitted securely in a fitting portion 70. With appropriate design of a heating device of a soldering iron, the fitting portion 70 selves to receive the soldering bit 68, as already mentioned hereinbefore with reference to Figure 11. Inside the working portion 69 is a heating rod 72 which is at least partially surrounded by the actual working portion 69 consisting 3q of porous material. At the lower end of the working portion 69, the heating rod 72 projects somewhat from the working portion 69 and therefore forms a part 71 of the surface of the working portion 69. In the present embodiment shown in Figure 15, this heating rod is rigidly connected to the fitting portion 68 and therefore also thermally coupled thereto. Owing to the direct thermal coupling of the working portion 69 via the fitting portion 70 to a heating device, as shown, for example, in Figure 11, extremely good conduction of the thermal energy to the working portion 69 and therefore extremely short heating times for heating up the working portion 69 are achieved. The surface portion 71 of the heating rod 72 projecting somewhat from the working portion 69 also permits direct discharge of heat, for example during an unsoldering process, to the solder to be removed, simplifying the melting thereof.

Figure 14 shows a working part 5 6 formed from two different porous materials. Thus, the working part 56 has a working portion 57 which can be formed from sintered bronze for holding and discharging solder, for example. This working portion is substantially conical in design and its cone tip 58 is rounded.

The working portion 57 is embedded in a covering 5 9 and projects with its cone tip 58 from the covering 59 axially at the: bottom. The covering 59 consists of a material, for example ceramic material, which is not capable of holding working material in the form of solder, but is permeable to air. In the present embodiment, the covering is surrounded by an air-tight casing 60 and forms an air-permeable annular duct 67 which is open at the bottom toward the tip of the cone 58 and is spatially limited radially externally by the casing 60 and radially internally by the working portion 57.

Above the working portion 57 there ends a suction duct 61 which opens into the covering 5 9 and is coupled to a corresponding suction device (not shown in the drawing). On the covering 5 9 there is provided a fitting thread 62 by means of which the covering 59 is fastened on a handle 63 together with the working portion 57. The suction duct 61 of the covering 5 9 penetrates through the fitting thread 63 and is connected to a suction duct 64 of the handle 63. An appropriate ring seal 65 which is arranged between the fitting thread 62 and the handle 63 is provided for sealing the two suction ducts 61 and 64. A further ring seal 66 is provided between the casing 60 and the lower end of the handle, so a suction stream acting through a corresponding suction device in the suction ducts 61 and 64 is continued through the porous material of the covering 5 9 to the lower end of the annular duct 67. Owing to this design of the working part, for example, during a soldering process by means of the working part, on the one hand solder can be applied at the soldering position for the soldering of two components and, at the same time, fumes formed during soldering can be aspirated directly at the soldering position via the working part. This suction stream simultaneously produces a cooling effect in the immediate vicinity of a soldering position to be produced, so excessive heating of heat-sensitive components outside the soldering position can be reliably prevented.

It will be appreciated that the above-mentioned embodiments can be extended as desired according to the field of application and special use-specific shaping and design of the working part with its working portion are conceivable. Thus, extremely small soldering bits which can be angled, for example for improved access to the working field, are. required for fine soldering work, -for example for the soldering in and out of IGs or 31D components.

The working part is produced by known methods of sintering, for example by hot pressing possibly with subsequent machining. The same applies to the other groups of materials such as ceramics and plastics materials mentioned by way of example.

To sum up, the advantages of the working part made of porous material according to the invention will be mentioned again: I Solder, flux and heat can be fed, stored and finely metered via the soldering bit or the working part designed as a soldering bit according to the invention.

Separate manual or automatic feeding of solder and flux can be omitted for a relatively small number of soldering positions or is possible through appropriate feed ducts only in the case of a larger number of soldering positions to be produced, the feeding of solder or flux being disconnected from the actual soldering process.

This means that the feeding of solder and flux via appropriate feed ducts only has to take place intermittently and continuous uniform soldering can nevertheless be carried out reliably.

Furthermore, the storage capacity through the porous material used via the working part and the soldering bit forms a working store of solder and/or flux for several soldering processes, and tests have shown that well over 50 soldering processes can be carried out with a substantially greater design of the soldering 20 bit.

The aspiration of excess solder or also excess flux through the • porous bit can also be carried out reliably but only in cases where the soldering bit is not saturated with these materials, i.e. solder or flux.

Overhead work is also permitted without drips of solder or flux.

Solder can also be saved owing to the automatically metered discharge of solder. Only the quantity of solder required for wetting the heated component can pass to the soldering position.

The working part according to the invention can also be used, in particular during soldering processes, as an aid for operating personnel with minimum experience of soldering because the feeding and quantity of solder are provided automatically and only the absolutely necessary quantity of solder can issue from the porous soldering bit, optimum metering automatically being achi eved.

Any porous materials which are capable of capillary action with the corresponding working substance or with the solder and which can therefore be held as working substance in the corresponding working part or soldering bit can be used as materials for the working part or for the soldering bit.

As already mentioned hereinbefore, various fields of application are envisaged for the working part according to the invention, such as for hot-melt adhesive guns or during hard soldering. In these various applications, it is merely necessary to adapt the porosity and the surface structure of the porous material used to the viscosity of the corresponding working medium such that the capillary action occurs reliably and a storage function of the working part with its working portion is therefore also ensured.

It will be appreciated that, for the various fields of application, the respectively required different heating temperatures for the working part will have to be applied by appropriate design of the heating device to be used.

Claims (5)

1. Device for producing joints between components and/or for coating surfaces, comprising a heating device (29, 29', 40, 5 49) with a working part (1, 7. 12, 13, 20, 22, 24, 26, 34, 45, 56, 69) by means of which a working substance required for producing the joint or the coating can be heated and can be brought into a plastic or molten state, the working part comprising means for the application of working substance and 10 means for the removal of working substance, characterized in that the working part (1, 7, 12, 13. 20, 22, 24, 26, 34, 45, 56, 60) comprises a working portion (2, 8, 15, 19, 21, 23, 25, 27, 46, 57, 69) which is designed as a tool for the application of working substance and consists at least in part of a porous material, in particular metallic sintered 25 material, sintered plastics material or of porous ceramic material which is used as a storage medium for the removal and for the application of the working substance.

2. Device according to claim 1, characterized in that the heating device (49) is integrated in the working part (45) 2Q and/or in the working portion (46) of the working part (45) or in that, for heating the working portion (69), a heating rod (72) is provided as heating device and in that the heating rod (72) is at least partially surrounded by the working portion (69) formed from porous material.

3. Device according to claim l or 2, characterized in that the working part (7) comprises at least one feed and/or aspiration duct (11) for feeding and/or aspiration of the working substance and in that the feed and/or aspiration duct (11) ends within the working portion (8) of the working part 30 (7) or in that the feed and/or aspiration duct penetrates right through the working part (7) with its working portion (8) .

4. Device according to one of claims l to 3, characterized in that the working part (12, 45) has a cavity (16, 53) for the working substance at least in the region of its working portion (15, 46) and in that the cavity (16, 45) of the 5 working part (12, 46) is connected to the feed and/or aspiration duct or in that, for filling the cavity (16) with working substance, an inlet bore (17) which is accessible from the exterior and opens into the cavity (16) is provided.

5. Device according to one of claims 1 to 4, characterized LQ in that the working part (1, 56) is at least partially surrounded by a casing (6, 60) which is impermeable to the working substance and in that the casing (6) together with the working part (1) forms a type of feed and/or aspiration duct which is connected to a feed arrangement and/or an aspiration ΰ arrangement for the feeding and aspiration of working substance.