Field of the Invention

This invention is a magnetic welding machine and relates to devices for joining two bodies with heating up of an adhesive substance, particularly to heat-treatment devices for joining preformed parts by pressing. A number of products show optimal performance characteristics if they are made of dissimilar materials. Joining of dissimilar metals, especially having a large length (ribbon-shaped), presents a more difficult challenge than joining of similar materials. The growing need for devices for joining dissimilar materials, and the production output of relevant equipment requires the expansion of the range and continuous improvement of technical means for the implementation of the claimed purpose.

Prior Art

A device for joining dissimilar materials and bodies is known, by means of which a laminated product comprising a flexible film and textile fabric laminated on the flexible film is produced, wherein the textile fabric is laminated on the side that is supposed to be subjected to compaction during the treatment of the laminated product. Therewith, the textile fabric has, for example, a structure of flat braiding. In particular cases of embodiment, the flexible film is a waterproof film, or a waterproof and moisture permeable film; the film is porous and is composed of a hydrophobic resin; the porous film is composed of a hydrophobic resin, or it has a layer of a hydrophobic resin on the side where there is a laminated textile fabric; epy porous film that is composed of a hydrophobic resin, or is a porous film of polytetrafluoroethylene; the flexible film additionally includes a fabric that is laminated on another side, i.e. a side that is opposite to the side on which the textile fabric is laminated (RU 2007137566).

A device for joining dissimilar materials and bodies is known, in which a thermoplastic layer as an adhesive medium is placed between connecting surfaces to be joined. Then the connecting surfaces and the adhesive medium that lies between them are put together, and at least one of the bodies is mechanically impacted so that friction is caused with the generation of heat causing the melting of the thermoplastic layer. The mechanical action is then stopped, and the thermoplastic material melted and fused to both connecting surfaces is cooled by removing heat to surrounding parts of the body, thereby it changes its aggregate state and becomes solid again (WO 96/01377). A device for implementing a method for joining two bodies is known, in which an adhesive medium is placed between the surfaces to be joined; and the connecting surfaces and the adhesive medium lying between them are put together, and at least on one of the bodies is mechanically impacted so that friction is caused and friction heat is generated, wherein the adhesive medium contains at least one cross-linkable polymer or a polymerized cross-linkable resin, which turns into a thermosetting material by virtue of friction heat. Use is made of a polymerized and cross-linkable resin, which turns into a thermosetting material by condensation polymerization or addition polymerization; the polymer or resin is pre-polymerized, particularly it is pre-condensed. Any mechanical action is stopped at the latest when at least one polymer or resin has been turned into the thermosetting material. The connecting surfaces and adhesive medium lying between them are pressed against each other during the mechanical action (RU 2294351).

The closest to the claimed technical solution is a device for heat sealing of a flexible coating with a base which comprises: a chamber for a particle bed fluidized using a gas stream which comprises a gas distributor, a diffusion grid, a bed of particles and a flexible covering sheet; a gas supply system; a pressing element that is capable of pressing the base to the particle bed. The chamber has at least one electromagnetic radiation system, positioned in a way that the waves are oriented toward the pressing element. Each of electromagnetic radiation systems comprises an electromagnetic wave generator, a waveguide and an antenna, wherein the above antenna is positioned under the particle bed and is intended for the propagation of electromagnetic waves at a solid angle, the vortex of which is the antenna, and its value is such that it covers the base. The chamber is surrounded by a metal housing which is designed to retain electromagnetic waves inside the body. The housing has a door to enter the flexible coating and the base inside the chamber. The device has at least one device for mixing waves inside the housing for the propagation of electromagnetic waves (RU 2669641 , a prototype).

Disadvantages of prior devices for joining are their structural complexity and the complexity of their operation, a long duration of the process of joining, and the fact that the resulting product is thermoplastic and therefore has only limited heat resistance, insufficient durability and reliability, as the bond dissociation energy is relatively low. This is the reason for an insufficient efficiency of their usage. The technical problem which is addressed by this technical solution lies in extending the range and enhancing the efficiency of such technical means which provide the joining of dissimilar materials.

The technical result achieved through the use of the claimed technical solution is to create an efficient alternative design of the above device for the implementation of the claimed purpose of joining dissimilar materials. The claimed device for joining dissimilar materials makes it possible to speed up the process of joining and to create a bonding that is more heat-resistant than the known bonding of dissimilar materials.

Summary of the Invention

The essence of the invention is that a device for joining dissimilar materials comprises a housing with a bonding formation zone, wherein ribbon-shaped structures are arranged with the possibility of placing the strips of dissimilar materials to be joined and a heating element in the form of a metal strip, the width and length of which are equal to the same of the bonding formation zone, to which an electric power source is connected for heating the layers to a welding temperature, and an arrangement for pressing a stack of the above layers; the means of pressing is made in the form of a group of magnets mounted in the housing on guides along the bonding formation zone, electrically insulated from the bonding formation zone and mounted in a way that it is possible to move them in the housing together with the heating element during heating and cooling.

Preferably, the device is completed with two heating elements in the form of metal strips on both sides of the stack of the above-mentioned layers.

Preferably, the electric power source is configured to ensure the heating of the heating element and a layer of a heat-activated adhesive substance that is additionally placed between them to temperatures, at which the melting and welding of strips of dissimilar materials together with the heat-activated layer take place.

Preferably, the magnets are selected from the condition for forming a force, which ensures the compression of the stack of directly attached strips of joined dissimilar materials that is sufficient for the interpenetration of substance molecules of the joined materials in the space between molecules of each other when they are heated up.

Preferably, the electric power source is configured to ensure the heating of the heating element to temperatures, at which the melting and welding of materials of layers joined together take place.

In particular cases of embodiment, the magnets are electric magnets that are insulated from the heating metal strip by means of a nonmagnetic spacer. Short description of drawings

Fig.l represents a device for joining dissimilar materials, a side view without the housing; Fig. 2 - a top view of the device shown in Fig. 1 ; Fig. 3 - a lateral section of the device shown in Fig.l.

The following is shown in the drawings:

1,5 - heating element - heating metal strips,

2,4 - strips (layers) of materials to be joined,

3 - layer of adhesive substance,

7 - magnets,

6 - electrical insulation; it can be an independent element, or part of elements 5 or 7,

8 - guiding element (washer) to move magnets 7,

9 - housing.

Parts 8 and 9 - a metal washer and a guide (housing) are structural parts that hold the magnets 7 in place and at the same time allow them to move together with the heating element during heating and cooling.

The magnetic welding machine for joining dissimilar materials comprises a housing 9 with a bonding formation zone where ribbon-shaped structures are arranged with the possibility of placing the strips 2, 4 of dissimilar materials to be joined and a heating element in the form of a metal strip 1 , the width and length of which are equal to the same of the bonding formation zone, to which an electric power source (not shown) is connected for heating up the strips 2,4 to a welding temperature, and an arrangement for pressing a stack of the above strips that is made in the form of a group of magnets 7 split into segments and mounted in the housing 9 on guides along the bonding formation zone, electrically insulated from the bonding formation zone, and mounted in a way that makes it possible to move them in the housing 9 together with the heating element 1 during heating and cooling.

The device can be designed with two heating elements and in the form of metal strips 1 and 5 on both sides of the stack of the above layers 2,4.

The electric power source is configured to ensure the heating of the heating element (the strip 5 or 1, or both strips 5 and 1) and the layer 3 of a heat-activated adhesive substance additionally placed between them to temperatures, at which the melting and welding of strips 2,4 of dissimilar materials together with the heat-activated layer 3 take place.

The magnets 7 are selected from the condition for forming a force, which ensures the compression of the stack of directly attached strips 1 - 5 that is sufficient for the interpenetration of substance molecules of the joined materials of the strips 2,4 in the space between molecules of each other when they are heated up.

The electric power source is configured to ensure the heating of the heating element (the strip 5 or 1, or both strips 1 and 5) to temperatures, at which the melting and welding of materials of the joined strips 2,4 take place.

Magnets 7 are in the form of electric magnets.

Detailed Description of the Invention

Preferred embodiment

The magnetic welding machine for joining dissimilar materials is used as follows.

If necessary, the layer 3 of a heat-activated adhesive substance is placed between the surfaces of strips 2,4 which are joined together. A heating element (the strip 5 or 1, or both strips 1 and 5) is placed on the opposite side (or on both sides), the above stack and the adhesive medium lying between them are then put together and mechanically impacted by means of an arrangement for pressing the above stack of strips, which is made in the form of a group of magnets 7.

The device makes it possible to join various materials by heating and compressing the joining area. During the process of joining, electric current heating up the metal strip 5 or the metal strip 1 , or concurrently the strips 1 and 5 to a required temperature, is fed via the metal strip 5 or the metal strip 1 , or concurrently via the strips 1 and 5, covering the strips 2, 4 of joined dissimilar materials and defining the width and length of the joining area.

Heat is transferred to the materials of joined strips 2,4 and the layer 3, if any, as a result of thermal emission which takes place due to the pressing of strips 2,4 of joined materials to the strip 1 and to the other strip 5 or to a metallic surface by means of permanent or electric magnets 7.

Parts 8 and 9 - a metal washer and a guide (housing) are structural elements that hold the magnets 7 in place and at the same time allow them to move in the guide 9 together with the heating element (the strip 5 or trip 1 , or the strips 1 and 5 concurrently) during heating and cooling.

The materials are joined as a result of an increase in the temperature within the bonding formation zone to the values at which the materials of the strips (layers) 2,4 are melted and welded themselves, or the layers 3 added to the joining area and having a lower melting point (e.g. heat-activated adhesive or hot melt adhesive composition) are melted and welded. When switched on, the heating elements 1, 5 increase in their size, so it is necessary either to stabilize their temperature and keep them constantly on, or to allow the heating elements 1 , 5 to increase in their size directly during the process of pressing.

In the described case, the width and thickness of the heating element is many times less than its length, and in order to reduce the negative effect of the rapid increase of the heating element 1,5 in size, it is required to ensure the possibility of an unhindered increase in its length during its pressing against the materials of joined strips 2,4. For this purpose, in the presented device, the magnets 7 move freely in the guide 9 along the line of thermal elongation of the heating element 5 or 1 or the strips 1 and 5 concurrently. The magnets 7 are split into segments which are pressed to the heating element 1 , or 1 and 5 under the action of a magnetic force, and when the size of this heating element changes, they move together with the heating element during both the increase in its size, and decrease in its size at cooling, thus a uniform pattern of bonding along the entire length is achieved.

Electromagnets or permanent neodymium magnets made of a neodymium-iron-boron alloy with the formation a tetragonal crystal structure Nd2Fel4B can be used as the magnets 7. Neodymium magnets are the strongest type of permanent magnets common in engineering.

The elements 1 and 5 are made of steel or materials having similar magnetic properties and properties of electric conductivity. These elements are heated up when electricity passes through them.

The element 6 is electrical insulation; it can be an independent element, or part of elements 5 or 7.

The elements 1 and 5 can be used as heating elements concurrently.

The strip 1 only may be used as a heating element; in this case, the strip 5 will be auxiliary; or the strip 5 only may be used as a heating element, in this case the element 1 will be auxiliary. The strip 5 then can be configured as an insertion made of any material, including with non-magnetic properties, and can be placed between the elements 1 and 2.

The device can be operated without using the strip 5. In this case, the magnets 7 press the heating element 1 directly to the material of layers 2, 3 and 4.

There may be the case where the materials 2 and 4 are joined together without using a heat-activated adhesive layer 3. In this case, the temperature and time of exposure to the heat from the heating element should be sufficient to weld the strips (layers) 2,4. There may be another adhesive layer 3 between the strips 2 and 4, and an additional layer of heat- activated adhesive medium can also be placed. In this case, the temperature and time of exposure to the heat from the heating element 1 or 1 and 4 shall be sufficient to activate the adhesive layer 3 or a layer of a hot melt adhesive composition.

Industrial applicability Thus, the embodiment of the claimed invention results in expanding the range of devices (a magnetic welding machine) for joining dissimilar materials through the creation of an original efficient device for joining materials which has high reliability and durability, the possibility of implementing its function and low-cost serial production.