Sonotrode, welding device using sonotrode, associated welding method and positioning method

Abstract

To provide a method of manufacturing a bottomed container for use in the packaging, food, and pharmaceutical fields.SOLUTION: There is provided a sonotrode (10) for friction welding of at least two joints (1, 3), which are at least partly made of weldable material, in particular a plastic material. The sonotrode comprises a base (12) having a first axial end (14) and an opposite second axial end (16), and is configured in that: additionally, adjacent to the second axial end (16), a work surface (20) is provided on the base (12) transversely to a central longitudinal axis (18); the work surface is attachable, in operation, to one of the at least two joints (1, 3); a bonding energy can be introduced laterally into a bonding zone between at least two joints (1, 3); and the shape of the sonotrode is adaptable or adapted to a contour of at least one of the two joints (1, 3).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The invention relates to a sonotrode for friction welding at least two joints made at least in part of a weldable material, in particular a plastic material, a corresponding welding device, a positioning method for positioning the first joint, as well as a corresponding welding method and an associated vessel. [Background technology]

[0002] In the manufacture of containers, such as for example yoghurt cups, disposable drinking cups or other containers with a bottom and / or intermediate bottom, firstly the body of the container is provided, for example in the form of a hollow cylinder. To close one side of this body, the bottom is fixed to the body, usually by means of an adhesive. Alternatively, the connection between the body and the bottom can be made by temperature heating of the joining partners, for example by means of hot air or a hot punch, or by mechanical connection, for example by means of a pressure element or roller, respectively.

[0003] The disadvantages here are the short cycle times and the laborious use of adhesives to connect the body with the bottom. Furthermore, in the production of such containers for the food and pharmaceutical sector, specific requirements must be observed, especially with regard to the adhesives used, which leads to high production costs. Furthermore, accessibility to the body is not always fully guaranteed.

[0004] The intended technical object of the present invention is therefore to provide an alternative manufacturing method for containers with a base, in particular for use in the packaging, food and pharmaceutical fields, where the manufacturing method should primarily provide a reliable connection between the body and the base of the container and should be economically optimized. Summary of the Invention

[0005] The above object is solved by a sonotrode according to claim 1, a corresponding welding device according to claim 5, a positioning method according to claim 9, a welding method according to claim 11 and a vessel according to claim 14. Advantageous embodiments and further developments arise from the following description, the drawings and the appended claims.

[0006] The inventive sonotrode for friction welding at least two joints made at least in part of a weldable material, in particular a plastic material, comprises a base body having a first axial end and an opposite second axial end, the base body having a central longitudinal axis extending through the first and second axial ends, along which the sonotrode is movable during operation or along which a deflection of the sonotrode may occur during operation, adjacent to the second axial end a working surface is provided transversely of the base body relative to the central longitudinal axis and is attachable during operation to one of the at least two joints so as to be able to introduce joining energy transversely into the joining zone between the at least two joints, the working surface preferably surrounding the base body without any interruption and comprising a first structure, the shape of which is adaptable or adapted to the outer shape of at least one of the two joints.

[0007] The above-mentioned inventive sonotrode will now be described in more detail based on the function of the welding device during the corresponding friction welding method, taking as a reference example the production of yogurt cups or disposable drinking cups as containers.

[0008] The cup as a container comprises a bottom as a first joint and a hollow body as a second joint as joints. The body is, for example, cylindrical or conical in shape. The body is closed on one side by a bottom. This means that the bottom is fixed adjacent to the axial end of the body. Such a bottom is also called a closed bottom. Alternatively, it is preferred to fix the bottom at another position in the body. In this case, the bottom is an intermediate bottom. The term bottom therefore generally includes a closed bottom or an intermediate bottom in this specification.

[0009] Depending on the welding method used, the material of the body must be weldable with the material of the housing. The body and / or the bottom must therefore comprise or consist of a weldable material at least in the joint portion. Examples of such weldable materials are, for example, correspondingly coated or laminated paper, etc. For example, paper includes a plastic coating, in particular made from polyethylene (PE) or polypropylene (PP). The body and the bottom, i.e. the second joint portion and the first joint portion, can be made of the same or different materials. The same material is particularly preferred, since a particularly reliable welded connection can be achieved.

[0010] With regard to a cup as an example of a container, the material of the hollow body is bent radially inward at one end in a first portion, followed by a bent radially inward towards the other end of the body in a second portion, thus forming a circumferential U-shape at one end of the inside of the body. Radially outward, the base has a portion that preferably extends parallel or nearly parallel to the surface normal of the base and that is at least partially disposed in the U-shape formed by the body later.

[0011] The welding device comprises a sonotrode according to the invention and a holding device having an emboss with a base and at least one pressure segment. With reference to a cup as an example, the base of the emboss preferably has a shape that is complementary to the body of the cup. However, this is not absolutely necessary for all containers, as will be explained below on the basis of alternative examples.

[0012] First, the welding method includes providing a first and a second joint made at least partially of a weldable plastic material. With respect to the cup as an example, the first joint, i.e. the bottom, is preferably placed on the base of the emboss. In that way, a part of the bottom extending parallel to the surface normal faces away from the base. Now, the second joint, i.e. the hollow body, is placed on the base of the emboss so that the U-shape of the body receives a part of the bottom extending parallel to the surface normal. In that way, the first joint and the second joint overlap in this part, so that the overlapping part is also called the joint zone or joint part.

[0013] The sonotrode and the emboss are now moved relative to each other, preferably along only one axis, so that the laterally or radially outer working surface of the sonotrode is located adjacent to the joint. To achieve a safe positioning of the joint, at least one pressure segment, preferably at least two pressure segments, which in the case of a cylindrical body are formed for example as a semicircle, are moved in the direction of the joint to be connected to each other until the joint is pressed against the working surface of the sonotrode. Preferably, there are so many pressure segments that the two joints can be welded to each other in one step at the joint.

[0014] The sonotrode is then induced to vibrate, thereby introducing bonding energy laterally or radially into the bond zone to form a welded connection between the first bond and the second bond.

[0015] In particular, the amplitude of the sonotrode, the pressure on the joint to be welded and the joining time are varied as parameters for setting up the welding method, so in a preferred embodiment the vibration frequency of the sonotrode is not varied.

[0016] After the welding process is finished, the working surface of the sonotrode and the at least one pressure segment are moved apart so that the first and second joints welded together can be removed from the welding device. For this purpose, the sonotrode is also moved relative to the annulus simultaneously with or after the pressure segments are moved apart.

[0017] The advantage of the present invention is that the design allows the production of friction welded connections for containers with closed contours, thus eliminating the need for separate adhesives. This facilitates the production of containers and provides a fast work cycle with a fast, efficient and cost-effective welding method. Similarly, the maintenance effort and space required for the welding equipment is low, and the effort to control the method is low, compared to other manufacturing methods.

[0018] In an advantageous configuration of the sonotrode, the working surface has a second structure, in particular in the form of a plurality of ridges. The joint, which is pressed against the sonotrode during operation by the second structure, is pulled by the sonotrode and starts to vibrate. The second structure of the sonotrode can therefore also be called a pulling structure. Preferably, the pulling structure bites into the adjacent joints so that the adjacent joints essentially perform the same movement as the sonotrode. In this way, a connection between the two components by friction welding can be effectively realized.

[0019] Furthermore, in cross section with respect to the longitudinal axis, the first structure preferably has one of the following shapes: circular, elliptical, oval, polygonal, preferably with rounded corners, or a combination thereof. In this way, the first structure, and thus the working surface of the sonotrode, can be adapted or optimally adapted to the hollow bodies configured at the joints connected to one another, for example cylindrical, conical, rectangular with rounded corners, etc.

[0020] In a particularly preferred embodiment of the sonotrode, the base comprises at least one channel, one end of which is arranged at the second axial end of the base of the sonotrode and the other end of which is connectable with a negative pressure source, so that the first joint can be held and / or positioned by means of the sonotrode. The advantage of this design is that the first joint, i.e. the bottom of the cup for the above example, can be held by the sonotrode. The sonotrode can thus position the bottom at the required position in the hollow body of the container and fix it there in combination with at least one pressure segment by friction welding. In that way the body of the container can be provided with an intermediate bottom, for example after a part of the volume of the container has already been filled with the product. In this case the base of the emboss can be made, for example, from one plane, on which the body is placed or placed, since it does not have to take on the stabilizing function of the body.

[0021] A corresponding positioning method using a sonotrode configured in this way therefore comprises in a first step providing a first junction, which is then placed adjacent to the second axial end of the sonotrode and held there by negative pressure, whereupon the sonotrode with the held first junction is placed in the required position, for example in a container already filled with a product.

[0022] A welding device according to the invention for friction welding at least two joints at least partially made of a weldable material, for example a plastic material, comprises a sonotrode according to the invention and a holding device having an emboss with a base body and at least one pressure segment, preferably at least two pressure segments, such that during operation of the welding device the at least two joints may be pressed against a working surface of the sonotrode by the at least one pressure segment. With regard to the operation method and the advantages obtained thereby, reference is made to the above description of the sonotrode according to the invention.

[0023] In a preferred embodiment of the welding device, the base of the emboss has a shape that can or is adapted to the contour of at least one of the two joints. In this design, the base of the emboss assumes, for example, a stabilizing and positioning function for the body of the container to be manufactured.

[0024] Preferably, at least one pressure segment has a shape that can be adapted or is adapted at least partially to the contour of at least one of the two joints. As mentioned above, the purpose of the pressure segment is to protect the welded connection at the joint. In order to achieve the same in as few steps as possible, preferably in only one step, there are several pressure segments that can press the entire joint against the working surface of the sonotrode. For this reason, it is preferred that the pressure segment or segments can be adapted or are adapted to the contour of the second joint.

[0025] It is further preferred that at least one pressure segment preferably comprises a structure on a part of the pressure face, in particular in the form of a plurality of ridges. By means of the plurality of ridges, the respective joint can be particularly securely held or fixed between the pressure face of the pressure segment and the working face of the sonotrode. In particular, the pressure face of the pressure segment bites into the respective joint adjacent to the pressure face by means of this second structure. In this way, an effective tight holding of the corresponding joint can be achieved. The structure on the pressure face of the pressure segment may therefore also be called a holding structure. This embodiment is particularly preferred in combination with a sonotrode having a second structure for tensioning the abutting joint.

[0026] A positioning method according to the invention for positioning a first joint, the first joint being at least partially made of a material, in particular plastic, that can be welded by a sonotrode having a base with a first axial end, an opposite second axial end and a lateral working surface present circumferentially around the base and at least one channel, one end of the channel being arranged at the second axial end of the base of the sonotrode and the other end of the channel being connected to a source of negative pressure by a sonotrode according to the invention, in particular in an embodiment having at least one channel, comprising the following steps: providing a first joint, positioning the first joint adjacent to the second axial end of the sonotrode, holding the first joint adjacent to the second axial end of the sonotrode by negative pressure and positioning the sonotrode in a required position with the first joint held therein. In a preferred embodiment, the positioning method further comprises the further step: releasing the first joint at the required position. As regards the advantages resulting therefrom, reference is made to the above description of the sonotrode with channels to avoid repetition.

[0027] The inventive welding method, in particular with the inventive welding device, comprises the steps of providing a first and a second joint made at least partially of a weldable material, arranging the first and the second joint between a working surface of the sonotrode and at least one pressure segment arranged transversely to the vibration direction of the sonotrode, in particular arranged so that the first and the second joint are pressed against the working surface of the sonotrode by the at least one pressure segment, vibrating the sonotrode to introduce a joining energy transversely into the joining zone and to establish a welded connection between the first and the second joint, and moving the working surface of the sonotrode and the at least one pressure segment apart, so that the first and the second joints welded together can be removed from the welding device. During the welding method, it is advantageous to induce the vibration of the sonotrode so that the working surface is aligned parallel to the vibration direction of the sonotrode. With regard to the functionality of the inventive welding method, reference is made to the above description of the inventive sonotrode. The advantages that arise correspond to those explained in connection with the sonotrode of the invention.

[0028] In a preferred embodiment of the welding method, the vibration of the sonotrode takes place in the ultrasonic range, preferably 15 kHz - 40 kHz, particularly preferably 20 kHz - 40 kHz. Due to the indicated frequency range, the sonotrode operates in the ultrasonic range, which ensures a fast, efficient and economical connection of the two joints to each other.

[0029] It is further preferred that the welding method further comprises the steps of the inventive positioning method, which are realized in the course of the providing and placing steps. The release step according to a preferred embodiment of the positioning method is preferably carried out during or after the welding step. With regard to the resulting advantages, reference is made to the description of the sonotrode with a channel as well as to the inventive positioning method.

[0030] The container of the invention consists of a base as a first joint and a hollow body as a second joint, the first and second joints being at least partially made of a weldable material and preferably completely welded to one another at the joint, in particular by the welding method of the invention. In a preferred embodiment of the container, the cross section of the joint has one of the following shapes: circular, elliptical, oblong, polygonal, preferably with rounded corners, or a combination of these shapes. Again, to avoid repetition, reference is made to the above description regarding advantages.

[0031] The present invention will now be described in detail with reference to the drawings, in which like reference numerals refer to like components and / or elements. [Brief description of the drawings]

[0032] [Figure 1] FIG. 1 is a schematic diagram of a first embodiment of a sonotrode according to the invention. [Diagram 2] 1A-1D are schematic diagrams of a first embodiment of a welding device of the invention at different stages of a manufacturing process of a first container. [Diagram 3] 1A-1D are schematic diagrams of a first embodiment of a welding device of the invention at different stages of a manufacturing process of a first container. [Figure 4] 1A-1D are schematic diagrams of a first embodiment of a welding device of the invention at different stages of a manufacturing process of a first container. [Diagram 5] 3A-3D are schematic views of a second embodiment of the welding device of the invention at different stages of producing a second container. [Figure 6] 3A-3D are schematic views of a second embodiment of the welding device of the invention at different stages of producing a second container. [Figure 7] 3A-3D are schematic views of a second embodiment of the welding device of the invention at different stages of producing a second container. [Figure 8] FIG. 4 is a schematic diagram of a third embodiment of the welding device of the present invention. [Figure 9] 3 is a flowchart of an embodiment of a positioning method of the present invention. [Figure 10] 2 is a flow chart of an embodiment of a welding method of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] An embodiment of the inventive welding device and the inventive sonotrode is illustrated by the production of containers such as yoghurt cups or disposable drinking cups and containers with an intermediate bottom.

[0034] The cup as a container comprises as components a bottom as a first joint 1 and a hollow body, for example in the shape of a cylinder or a cone, as a second joint 3. The body is closed on one side by the bottom. The bottom is therefore fixed adjacent to the axial end of the body. In this respect, reference is made to the diagrams in figures 2 to 4. Alternatively, it is preferred to fix the bottom at another position of the body, as shown in figures 1 and 5 to 8. In this case, the bottom is an intermediate bottom.

[0035] Depending on the welding method used, the material of the body must be welded to the material of the bottom. Therefore, the body and / or the bottom must contain or be made of a weldable material at least in the joint area. Examples of such weldable materials are correspondingly coated or laminated paper and the like. For example, paper has a plastic coating, in particular of polyethylene (PE) or polypropylene (PP). The body and the bottom, i.e. the second joint 3 and the first joint 1, can consist of the same material or of different materials. The same material is particularly preferred, since a particularly reliable welded connection can be achieved.

[0036] With particular reference now to FIG. 1, a first embodiment of a sonotrode 10 for friction welding a first joint 1 and a second joint 3 will be described. The sonotrode 10 comprises a base 12 having a first axial end 14 and an opposite second axial end 16. The base further comprises a central longitudinal axis 18, which extends through the first axial end 14 and the second axial end 16. In operation, the sonotrode 10 is movable or capable of performing a movement along the central longitudinal axis 18, as can be seen in FIGS. 3 and 6 by the sign arrows labeled S with respect to the direction of vibration.

[0037] Adjacent to the second axial end 16, a working surface 20 is provided on the base 12 transversely to the central longitudinal axis 18. This working surface 20 may be joined to one of the two joints 1, 3 during operation, so that a joining energy can be introduced transversely to the joining zone or joint between the first joint 1 and the second joint 3. In so doing, the working surface 20 circumferentially surrounds the base 12, preferably without interruption, and comprises a first structure, the shape of which can be adapted or is adapted to at least the contour of the second joint 3. The shape of the first structure can be, for example, a diamond, a wavy line, a line, etc.

[0038] For example, the first structure has, relative to the longitudinal axis 18, one of the following shaped cross-sectional shapes: circular, elliptical, oval, polygonal, preferably with rounded corners, or a combination thereof. In that way, the first structure of the sonotrode 10, and thus the working surface 20, can be or is optimally adapted to the joints 1, 3 that are to be connected to hollow bodies formed, for example, cylindrical, conical, rectangular with rounded corners, etc.

[0039] Furthermore, the working surface 20 of the sonotrode 10 has a second structure, in particular in the form of a number of ridges. The joints 1, 3, which are pressed against the sonotrode by the second structure during operation, are pulled and vibrated by the sonotrode 10. The second structure of the sonotrode 10 may therefore also be called a pulling structure. Preferably, the pulling structure bites into the adjacent joints 1, 3, such that the adjacent joints 1, 3 essentially perform the same movement as the sonotrode 10. In this way, a connection between the two components or between the joints 1, 3 by friction welding can be effectively performed.

[0040] The above-mentioned sonotrode of the present invention will now be described in more detail with reference to Figs. 2 to 4 based on the function of the welding device during the corresponding friction welding method, with the production of yogurt cups or disposable drinking cups as containers being taken as a reference example.

[0041] Referring to a cup as an example of a container, the hollow body is bent radially inward at one end in a first portion, followed by a bent in a second portion toward the other end of the body, forming a circumferential U-shape at one end of the interior of the body as the second joint 3. The base as the first joint 1 has a radially outward portion, which preferably extends parallel or nearly parallel to the surface normal of the base, and is at least partially disposed within the U-shape formed by the body.

[0042] The welding device comprises a sonotrode 10 and a holding device having an emboss 40 with a base 42 and at least one pressure segment 50. With reference to Figures 2 to 4, the base 42 of the emboss 40 has a shape complementary to the body of the cup as the second joint 3. In this configuration, the base 42 of the emboss 40 assumes the function of stabilizing and positioning the body of the container to be manufactured. However, this is not an absolute requirement for all containers, as will be explained later with respect to the embodiment shown in Figures 5 to 7.

[0043] In the illustrated embodiment, a pressure segment 50, preferably at least two pressure segments 50, are indicated diagrammatically by arrows. The pressure segments 50 have a shape that can or is at least partially adapted to the contour of the second joint 3. It is the role of the pressure segments 50 to ensure a welded connection in the joint area. Since there are several pressure segments 50, this may be done in as few steps as possible, preferably only one step, the pressure segments being able to press the entire joint area against the working surface 20 of the sonotrode 10. For this reason, it is preferred that the pressure segment(s) 50 can or is adapted to the contour of the second joint 3.

[0044] Advantageously, the pressure segment 50 has a structure, preferably in the region of the pressure face, which is present in particular in the form of a plurality of ridges. By means of the plurality of ridges, the respective joints 1, 3 can be particularly securely held or fixed, respectively, between the pressure face of the pressure segment 50 and the working face 20 of the sonotrode 10. In particular, the pressure face of the pressure segment 50 bites into the respective abutting joints 1, 3 by means of this structure. In this way, an effective holding of the corresponding joints 1, 3 can be achieved. The structure of the pressure face of the pressure segment 50 can therefore also be called a holding or holding structure. This embodiment is particularly preferred in combination with a sonotrode 10 which is provided with a second structure for tensioning the adjacent joints 1, 3.

[0045] The welding method first comprises the step of providing a first joint 1 and a second joint 3, which are at least partially composed of a weldable plastic material. First, the first joint 1, i.e. the bottom, is placed on the base 42 of the emboss 40. Here, a part of the bottom surface extending parallel to the surface normal faces away from the base 42. The second joint 3, i.e. the hollow body, is placed on the base 42 of the emboss 40 such that the U-shape of the body receives a part of the bottom extending parallel to the surface normal. The overlapping area is therefore also called the joining zone or joining part or area, since the first joint 1 and the second joint 3 overlap in this area or part. This is illustrated in FIG. 2.

[0046] Here, the sonotrode 10 and the emboss 40 are moved relative to each other, preferably along only one axis, so that the lateral or radial outer working surface 20 of the sonotrode 10 is located next to the joint. To achieve a reliable positioning of the joint, at least two pressure segments, indicated diagrammatically by arrows 50 and formed, for example, semicircular in the case of a cylindrical body, are moved in the direction of the joints 1, 3 to be connected to each other until the joints 1, 3 are pressed against the working surface 20 of the sonotrode 10. Preferably, there is the required number of pressure segments 50 so that the two joints 1, 3 can be welded to each other at the joint in one step. The resulting arrangement can be seen in FIG. 3.

[0047] Here the sonotrode 10 is induced to vibrate, whereby joining energy is introduced laterally or radially into the joining zone or joint, forming a welded connection between the first joint 1 and the second joint 3.

[0048] In particular, the amplitude of the sonotrode 10, the pressure applied to the joints 1, 3 to be welded as well as the joining time as parameters for setting up the welding method are varied. In a preferred embodiment, no change in the oscillation frequency of the sonotrode 10 occurs.

[0049] Once the welding process is completed, the working surface 20 of the sonotrode 10 and the at least one pressure segment 50 are moved apart, so that the first joint 1 and the second joint 3 welded together can be removed from the welding device. For this purpose, the sonotrode 10 is also moved relative to the emboss 40 simultaneously with or after the pressure segments 50 are moved apart. In this regard, please refer to FIG. 4.

[0050] The container so produced consists of a bottom as a first joint 1 and a hollow body as a second joint 3. The first joint 1 and the second joint 3 are at least partially made of a weldable material and are welded to each other at the joint, preferably completely welded. In cross section, the joint preferably has one of the following shapes: circular, elliptical, oblong, polygonal, preferably with rounded corners, or a combination thereof.

[0051] The advantage of this welding device is therefore that it allows a friction welded connection to be established in the case of containers with a closed contour, thus eliminating the need for a separate adhesive. This facilitates the manufacture of the containers and provides a fast work cycle due to a fast, efficient and low-cost welding process. Likewise, compared to other manufacturing methods, the maintenance effort and the space required for the welding device are less, as are the efforts for controlling the process. Furthermore, the risk of possible damage to the product to be filled, as in the case of thermal melting of the joining partners, for example by hot air or a hot punch, is reduced.

[0052] A second embodiment of the welding device is described with reference to Figs. 5 to 7. It serves to manufacture containers with a hollow body as the second joint 3 and an intermediate bottom as the first joint 1. This welding device differs from the first embodiment in particular because the emboss 140 used is made only with a plane on which the body is placed or placed as a base. A shape of the base 142 that is formed complementarily to the body is not necessary, since it does not have to assume any stabilizing function for the body. However, it is advantageous for the base 142 to have positionability with respect to the body in order to allow a safe positioning.

[0053] FIG. 8 shows a further embodiment of a sonotrode 110, comprising a base 112 having a first axial end 114 and an opposite second axial end 116. Here, the base 112 has at least one channel 122. One end of the channel 122 is arranged at the second axial end 116 of the base 112 of the sonotrode 110. The other end of the channel 122 is connectable to a negative pressure source 130. This means that the first joint 1 can be held tightly and / or positioned by the sonotrode 110. The advantage of this configuration is that the first joint 1, i.e. the bottom of the cup with reference to the above example, can be held tightly by the sonotrode 110. The sonotrode 110 can thus be arranged with its bottom at a desired position in the hollow body of the container and fixed in that position in combination with at least one pressure segment 50 by friction welding. In that way, the body of the container can be provided with an intermediate bottom, for example after a partial volume of the container has been filled with a product. In this regard, please refer to the manufacture of a container as an example, as shown in FIGS.

[0054] A corresponding positioning method with a sonotrode 100 configured in such a way is explained with reference to FIG. 9. Firstly, the provision of the first joint 1 is carried out in a first step a. The first joint 1 is then placed adjacent to the second axial end 116 of the sonotrode 110 (step b) and held there by negative pressure (step c). The sonotrode 110 now has the first joint 1 held therein and is positioned in a required position in a step d, for example as an intermediate bottom of a container already filled with a product. Then, in a step e, the release of the first joint 1 is carried out in the required position. With reference to the welding method described below, this may be carried out during or after the welding of the intermediate bottom as the first joint 1 and the body as the second joint 3.

[0055] Finally, an embodiment of a welding method is described with reference to figure 10. A first step A involves the provision of a first joint 1 and a second joint 3 made at least partially of a weldable material. This step can include the positioning method described above, in particular if a sonotrode 110 with a channel 122 is used.

[0056] The first joint 1 and the second joint 3 are then placed between the working surface 20, 120 of the sonotrode 10, 110, which is arranged transversely to the vibration direction of the sonotrode 10, 110, and at least one pressure segment 50. This is done in particular in such a way that the first joint 1 and the second joint 3 are pressed against the working surface 20, 120 of the sonotrode 10, 110 by the at least one pressure segment 50. In this position, in step C, an inducement to vibrate the sonotrode 10, 110 is performed, whereby a joining energy may be introduced transversely into the joining zone, and a welded connection is formed between the first joint 1 and the second joint 3. Finally, in step D, the working surface 20, 120 of the sonotrode 10, 110 and the at least one pressure segment 50 are moved away from each other, whereby the first joint 1 and the second joint 3 welded to each other can be removed from the welding device. In the course of the welding method, the induction of vibration of the sonotrode 10, 110 is advantageously performed in such a way that the working surface 20, 120 is arranged parallel to the vibration direction of the sonotrode. Furthermore, the vibration of the sonotrode 10, 110 is advantageously performed in the ultrasonic range, preferably between 15 kHz and 40 kHz, particularly preferably between 20 kHz and 40 kHz. In particular, the indicated frequency range allows the sonotrode 10, 110 to operate in the ultrasonic range, which ensures a fast, efficient and economical connection of the two joints 1, 3 with each other. [Explanation of symbols]

[0057] 1 1st joint 3 Second joint 10 Sonotrode 12 Base 14 First axial end 16 second axial end 18 Central Longitudinal Axis 20 Work Surface 40 Ambos 42 Base 50 Pressure Segments 110 Sonotrode 112 Base 114 first axial end 116 second axial end 120 work surface 122 Channels 130 Negative pressure source 140 Ambos 142 Base S Vibration direction of sonotrodes 10 and 110

Claims

1. A sonotrode (10, 110) for friction welding at least two joints (1, 3) made at least in part of a weldable material, a) a base (12, 112) having a first axial end (14, 114) and an opposite second axial end (16, 116), said base (12, 112) having a central longitudinal axis (18) extending through said first axial end (12, 112) and said second axial end (14, 114), along which said sonotrode (10, 110) is movable during operation; A sonotrode (10, 110) comprising: b) adjacent said second axial end (16, 116) and transverse to said central longitudinal axis (18), said base (12, 112) is provided with a working surface (20, 120) which, in operation, is attachable to one of said at least two joints (1, 3) so that joining energy can be introduced laterally into a joining zone between said at least two joints (1, 3); c) said working surface (20, 120) circumferentially surrounds said base body (12, 112) and comprises a first structure, the shape of which is adaptable to the contour of at least one of said two joints (1, 3); Sonotrode (10, 110).

2. The sonotrode (10, 110) of claim 1 , wherein the working surface (20, 120) has a second structure.

3. 3. The sonotrode (10, 110) of claim 1 or 2, wherein in a cross section relative to the longitudinal axis (18), the first structure has one of the following shapes: circular, elliptical, oval, polygonal, or combinations thereof.

4. 2. The sonotrode (110) of claim 1, wherein the base (112) comprises at least one channel (122), one end of which is arranged at the second axial end (116) of the base (112) of the sonotrode (110) and the other end of which is connectable to a negative pressure source (130), such that one of the at least two junctions (1, 3) can be held and / or positioned using the sonotrode (110).

5. A welding device for friction welding at least two joints (1, 3) at least partially made of weldable materials, comprising: a) a sonotrode (10, 110) according to claim 1; b) a retaining device having an embossment (40, 140) with a base (42, 142) and at least one pressure segment (50); A welding device comprising: c) during operation of the welding device, the at least two joints (1, 3) can be pressed against a working surface (20, 120) of the sonotrode (10, 110) by the at least one pressure segment (50); Welding equipment.

6. 6. The welding device according to claim 5, wherein the base (42) of the emboss (40) has a shape that is adaptable to the contour of at least one of the two joints (1, 3).

7. 7. The welding device according to claim 5 or 6, wherein the at least one pressure segment (50) has a shape that is at least partially adaptable to the contour of one of the at least two joints (1, 3).

8. The welding apparatus of claim 5 or 6, wherein the at least one pressure segment (50) comprises a structure.

9. 5. A method for positioning a first joint (1) at least partially made of a weldable material by means of a sonotrode (110) according to claim 4, having a base (112) with a first axial end (14, 114), an opposite second axial end (116) and a lateral working surface (120) present circumferentially around the base (112) and at least one channel, the method comprising: a) providing said first joint (1) (step a); b) positioning the first junction (1) adjacent a second axial end (116) of the sonotrode (110) (step b); c) holding a first junction (1) adjacent to the second axial end (116) of the sonotrode (110) by negative pressure (step c); d) positioning the sonotrode (110) while holding the first joint (1) in a desired position (step d); A positioning method comprising:

10. Further steps: e) releasing the first joint (1) at the required position (step e); The method of claim 9 further comprising:

11. A welding method using the welding apparatus according to claim 5, a) providing a first joining portion (1) and a second joining portion (3) made at least in part of a weldable material (Step A); b) arranging the first junction (1) and the second junction (3) between a working surface (20, 120) of the sonotrode (10, 110) and the at least one pressure segment (50), step B, the working surface (20, 120) being arranged transversely to the vibration direction of the sonotrode (10, 110); c) inducing vibrations of the sonotrode (10, 110) to introduce joining energy laterally into the joining zone to establish a welded connection between the first joint (1) and the second joint (3) (step C); d) moving the working surface (20, 120) of the sonotrode (10, 110) and the at least one pressure segment (50) apart, so that the first and second joints (1, 3) welded together can be removed from the welding device (step D); A welding method comprising:

12. 12. The welding method according to claim 11, wherein the vibration of the sonotrode (10, 110) is performed in the ultrasonic range.

13. The welding method according to claim 11, further comprising the steps of the positioning method according to claim 9, the steps of the positioning method according to claim 9 being realized during the providing step.

14. A container comprising a bottom as the first joint (1) and a body as the second joint (3), the first joint (1) and the second joint (3) being at least partially made of a weldable material and being welded to each other at the joint by the welding method according to claim 11.

15. 15. The container of claim 14, wherein in cross section, the interface portion has one of the following shapes: circular, elliptical, oval, polygonal, or a combination of these shapes.

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