Ultrasonic welding device with a side slide

Abstract

The present invention relates to an ultrasonic welding device for welding metallic materials, such as welding stranded wires, characterized in that a drive device is arranged and designed in such a way that the drive device causes the relative movement of the first contact surface (6, 8) with respect to the second sealing surface both in a transverse direction, which runs perpendicular to the welding direction, and in the welding direction.

Description

[0001] Ultrasonic welding device with side slider

[0002] The present invention relates to an ultrasonic welding device for welding metallic materials, such as stranded wires, comprising a welding chamber for receiving the materials to be welded, a sonotrode with a first sealing surface, a counter-tool with a second sealing surface, and at least one first side slider with a first contact surface, wherein the welding chamber is bounded at least by the first and second sealing surfaces and the first contact surface, wherein the first sealing surface is movable relative to the second sealing surface in a welding direction, and the first contact surface is movable relative to both the first and second sealing surfaces. Such ultrasonic welding devices are known in principle.

[0003] For example, stranded wires can be welded together or to a metallic contact part using ultrasound. For this purpose, the materials to be joined or welded are placed in a welding chamber. The welding chamber is designed to securely hold the materials to be welded during the welding process.

[0004] The sonotrode is the component of the ultrasonic welding device that is subjected to ultrasonic vibrations during the welding process and has a first sealing surface that is in contact with the material being welded. Therefore, this first sealing surface also forms a wall of the welding chamber. Furthermore, a counter tool (often also called an anvil) is provided, which has a second sealing surface and works together with the sonotrode to fix the materials being welded during the welding process. Therefore, this second sealing surface also forms a wall of the welding chamber. During the welding process, the sonotrode and the counter tool, or rather the first and second sealing surfaces, can be moved relative to each other in the welding direction to apply a predetermined force to the materials being welded.

[0005] To prevent the material being welded from laterally escaping the welding chamber during the welding process, the welding chamber is bounded on at least one side, and preferably on two sides, by a side slide with a contact surface. To facilitate the insertion of the materials into the welding chamber, the side slide is moved relative to the sealing surfaces during removal and insertion of the materials. This movement typically occurs approximately perpendicular to the welding direction.

[0006] Especially when stranded wires are to be welded onto a metallic contact element, the metallic contact element is usually somewhat wider than the wire being welded. Since only the strands need to be held laterally during welding, the side slider moves along the top of the metallic element in a direction perpendicular to the welding direction until it reaches the desired position to define the weld area. During this movement perpendicular to the welding direction, abrasive contact can occur between the top of the metallic contact element and the underside of the side slider.

[0007] Therefore, one embodiment already provides for moving the sideshift not only perpendicular to the welding direction, but also parallel to it. However, this requires two drives, which increases the cost of the device. Furthermore, during the welding process, a considerable force is exerted on the contact surfaces of the sideshift in a direction perpendicular to the welding direction, which must be absorbed by the drive, thus significantly increasing the stability requirements of the drive mechanism.

[0008] Based on the described state of the art, the object of the present invention is therefore to provide a simpler and more cost-effective solution.

[0009] According to the invention, this problem is solved by providing a single drive device which is arranged and designed in such a way that the drive device causes the relative movement of the first contact surface relative to the second sealing surface both in a transverse direction perpendicular to the welding direction and in the welding direction.

[0010] The first contact surface is movable between a welding position, in which it defines the welding area, and an opening position, in which it opens the welding area. The drive mechanism allows the first contact surface to move back and forth between the welding and opening positions.

[0011] By using only one drive device that allows both directions of movement simultaneously, the costs of the ultrasonic welding device can be significantly reduced, and at the same time, when welding stranded wire as already mentioned, it can be ensured that no wear marks are produced on the top of the metallic contact element or on the welded stranded wire when moving the side sliders.

[0012] Although the present invention is fundamentally suitable for ultrasonic welding devices for welding any metallic contacts, it was developed for welding stranded wires to a metallic contact element, and this is the preferred variant. In these cases, the welding chamber has a lower section designed to receive the contact element and an upper section designed to receive the stranded wire. The first contact surface of the first side slider has a first contact surface section that bounds the upper section of the welding chamber and a second contact surface section that bounds the lower section of the welding chamber, the first contact surface section and the second contact surface section being arranged perpendicular to each other. The welding chamber is preferably rectangular.If, as described, it consists of an upper and a lower section, the upper section, which is intended to hold the strands, is preferably rectangular. The lower section, which is intended to hold the metallic contact part, may also be rectangular. Alternatively, it may be open on the sides.

[0013] The welding area is enlarged or reduced via the first contact surface section as the side slide moves. Since the second contact surface section is arranged perpendicular to this, it rests on or almost rests on the metallic contact part in the welding position.

[0014] Although the following refers to an upper section and a lower section of the welding chamber, the arrangement could also be exactly reversed, so that the metallic contact part is arranged in the upper section and the strand in the lower section, although this is not the preferred embodiment.

[0015] In a further preferred embodiment, the drive device comprises a toggle lever with a first and a second lever, wherein the first lever is attached at one end to a stationary element by means of a first pivot joint which allows the first lever to rotate about a first axis of rotation, and at its other end is attached to the second lever via a second pivot joint, wherein the second pivot joint allows the second lever to rotate about a second axis of rotation which is arranged parallel to the first axis of rotation, wherein the second lever is connected at its end opposite the second pivot joint to the first side slide, and wherein a linear drive element is provided which is operatively connected to the toggle lever.

[0016] The toggle lever thus provides the combination of movement in the welding direction and perpendicular to it, while the linear drive element only provides movement in one direction, which is then redirected accordingly via the toggle lever.

[0017] In a preferred embodiment, the linear drive element is operatively connected to the second lever or the side slider, wherein the linear drive element or the side slider is preferably connected to the second lever via a connecting element which provides a positive locking connection between the linear drive element and the second lever or side slider in the welding direction and allows a relative movement perpendicular to the welding direction between the linear drive element on the one hand and the second lever or side slider on the other.

[0018] This type of connection ensures that the linear drive element moves the second lever in the welding direction. However, due to the connection between the second and first levers, moving the first lever in the welding direction causes the second lever to shift relative to the linear drive element in a direction perpendicular to the welding direction.

[0019] In a preferred embodiment, the side slider is movable back and forth between a welding position and an opening position, wherein in the welding position the toggle lever is oriented such that a force applied perpendicularly to the first contact surface is not transmitted to the linear drive element, but is absorbed by the lever arrangement. This is the case when the levers assume an overextended or nearly extended configuration in the welding position and a bent configuration relative to each other in the opening position.

[0020] In the open position, the first and second levers form an angle β less than 180°. As the levers move from the open position to the welding position, the angle β formed by the two levers increases. In the welding position, the angle β can be 180°, representing the extended configuration, or β > 180°, representing the hyperextended configuration. When the two levers form an angle of 180°, the force applied to the side slider is transmitted directly to the stationary element via the levers, thus exerting no force on the linear actuator. To achieve locking via the toggle lever in the welding position, the toggle joint can be hyperextended beyond its dead center, i.e., to an angle β > 180°.

[0021] In a further preferred embodiment, the first or second lever has lever elements connected to each other via an adjusting device, the adjusting device allowing adjustment of the relative position between the two lever elements. The adjusting device thus allows the length of the lever, and therefore also the exact position of the side slider or the first contact surface in the welding position, to be determined. In a preferred embodiment, the adjusting device has a threaded rod with two threaded sections of different pitches that engage in corresponding threaded bores in which lifting elements are inserted. Such a differential thread allows the two lever elements to be adjusted very precisely relative to each other.

[0022] Although an embodiment with only one side slide is conceivable in principle, a preferred embodiment provides a second side slide with a second contact surface, whereby the welding area is also limited by the second contact surface.

[0023] It is particularly preferred if the drive device is arranged and designed such that it moves the first and second side sliders simultaneously, both in the welding direction and in a direction perpendicular to the welding direction. The movement perpendicular to the welding direction can be in opposite directions for the two side sliders. Advantageously, at least one section of the first contact surface is oriented such that it forms an angle θ with the first sealing surface. This angle is preferably greater than 45° and, in a particularly preferred embodiment, is 90°. If a second side slider with a second contact surface is provided, the first and second contact surfaces are advantageously arranged parallel to each other in every position.

[0024] In a further preferred embodiment, the drive device is configured such that, in every position of the side slide, the first contact surface forms the same angle θ with the first sealing surface. The sequence of movements is thus such that the relative orientation of the side slide remains exactly the same during its movement.

[0025] Further advantages, features, and applications will become clear from the following description of a preferred embodiment and the accompanying figures. These show:

[0026] Figure 1 shows a schematic representation of an arrangement according to the invention with side sliders in the welding position and

[0027] Figure 2 shows a schematic representation of an arrangement according to the invention with side sliders in the open position.

[0028] Figure 1 shows a schematic representation of a part of an ultrasonic welding device according to the invention. The structure of the part of the ultrasonic welding device not shown is known to those skilled in the art.

[0029] In the example shown, a metallic strand (not shown) is to be connected to a metallic contact part 2. Therefore, the metallic contact part 2 is placed on a counter tool.

[0030] 1. The surface of the counter-tool 1 that comes into contact with the metallic contact part 2 is called the second sealing surface. Above the metallic contact part

[0031] The wire is arranged in Figure 2. The welding chamber, in which the metallic contact part 2 and the wire are arranged, is designated by reference numeral 3. Above the wire is a sonotrode (not shown) which has a first sealing surface that comes into contact with the wire during the welding process. The sonotrode is excited by an ultrasonic vibration in a known manner and is movable relative to the counter tool 1 in a welding direction (vertical direction in Figures 1 and 2) in order to reduce or enlarge the welding chamber 3. The first sealing surface of the sonotrode can thus be moved towards or away from the second sealing surface of the counter tool 1. The space between the two sealing surfaces is called the welding chamber 3. This welding chamber is bounded above by the first sealing surface of the sonotrode and below by the second sealing surface of the counter tool 1.To counteract lateral displacement of the wire during the welding process, side sliders 4, 5 are provided on both sides, which come into contact with the materials to be joined. Both side sliders have a first contact surface 6, 8 and a second contact surface 7, 9, respectively, each of which has two contact surface sections: an upper contact surface section 6, 7 and a lower contact surface section 8, 9. In the welding position shown in Figure 1, the upper contact surface section 6, 7 is in contact with the wire. The lower contact surface section 8, 9, which is arranged approximately perpendicular to the upper contact surface section 6, 7, is in contact with the top surface of the metallic contact part 2. The upper contact surface section 6, 7 forms an angle θ of 90° with the first sealing surface of the sonotrode.

[0032] Thus, in the welding position shown in Figure 1, the welding area 3 is limited not only by the first and second sealing surfaces, but also by the first and second contact surfaces 6, 7, 8, 9 of the side sliders 4,5.

[0033] In order to bring the metallic contact part 2 and the wire into the desired position before processing and to remove them from the ultrasonic welding device after connection, it is necessary not only to move the sonotrode upwards, but also to move the side slides 4,5 away from the welding chamber 3.

[0034] For example, as is common in the prior art, the side slides 4,5 could be moved horizontally, with the result that the lower contact surface section 8,9, which is in contact with the metallic contact part 2, scrapes over the metallic contact part 2 and may damage it.

[0035] If, instead, the side sliders 4,5 are moved vertically upwards, as is also known from the prior art, the metallic contact part 2 can be protected from damage, but the edge surfaces of the strand may now be damaged by the upper contact surface sections 6,7 or by residues adhering to them.

[0036] Therefore, it is already known in some prior art to move the side slides 4, 5 simultaneously in both the vertical and horizontal directions using two separate linear drives, but this is complex and expensive in terms of design. Furthermore, relatively high horizontal forces act on the side slides 4, 5 during the welding process, i.e., when the ultrasonically excited sonotrode is pressed towards the counter tool 1.

[0037] According to the invention, a technique has been developed which achieves a positively guided movement of the side sliders 4, 5 by means of a toggle lever 12, 17 on a circular path. Due to the positive guidance, only one linear drive 16 in the vertical direction is necessary.

[0038] Only the side slide 4 shown on the left in the figures will be described below. The side slide 5 shown on the right in the figures is a mirror image, so a separate description is unnecessary.

[0039] Each side slider 4, 5 has a toggle lever with a first lever 12 and a second lever 17. The first lever 12 is attached at one end to a stationary element 20 by means of a first pivot joint 11, which allows the first lever 12 to rotate about a first axis of rotation, and at its other end to the second lever 17, or in the illustrated embodiment to a base part 14 connected to the second lever 17, via a second pivot joint 10. The second pivot joint 10 allows the second lever 17 to rotate about a second axis of rotation, which is arranged parallel to the first axis of rotation.

[0040] The second lever 17 is connected to the first side slider 4 at its end furthest from the second pivot joint 10. In the welding position shown in Figure 1, the first lever 12 and the second lever 17 form an angle β of 180°. As a result, the lateral forces are transmitted via the second lever 17 and the first lever 12 to the stationary element 20 and do not load the linear drive 16.

[0041] The second lever 17 and the second pivot joint 10 rest on a support 15, so that they can be moved in a horizontal direction relative to it.

[0042] If, after the welding process is complete, the welded product is to be removed and new materials to be joined are to be inserted, the sonotrode is moved vertically upwards. In addition, a force is exerted on the support 15 in the vertical direction by means of the linear drive 16. This causes the side slide 4, or the second lever 17 connected to the side slide, to also move vertically. However, since the second pivot joint 10 is connected to the first pivot joint 11, and thus to the stationary element 20, via the first lever 12, this simultaneously results in a horizontal movement of the side slide 4 to the left. This causes the side slide to move into the open position shown in Figure 2. The connection between the linear drive 16 and the second lever 17, or side slide 4, is positively locked in the vertical direction, which ensures that the side slide 4, or side slide 4, remains in the open position.The second lever 17 always moves vertically together with the linear actuator 16. However, the connection between the linear actuator 16 and the side slide 4, or the second lever 17, or the base part 14 allows for relative movement of the side slide 4, or the second lever 17, in the horizontal direction. This is necessary due to the chosen toggle lever arrangement. As a result, the side slide 4 moves in a circular path without twisting, which means that a single linear actuator 16 ensures that both the upper contact surface section 6 and the lower contact surface section 8 are no longer in contact with the weld product at the very beginning of the opening movement and therefore cannot cause any damage. In the open position, the angle β is significantly less than 180°.

[0043] To allow for precise horizontal adjustment of the sideshifts 4, 5, an adjusting device 13 is located in the first lever 12. This device allows the length of the first lever 12 to be adjusted. The adjusting device 13, for example, has a threaded rod with two separate threads of different pitches that engage in corresponding threaded bores in two lever elements, which together with the threaded rod form the first lever 12. By rotating the threaded rod, the differential thread attached to it enables very fine adjustment of the sideshift 4's position in the horizontal direction.

[0044] Additionally, a locking device 18, 19 is provided, which comprises a piston 18 in whose end face an undercut groove 19 is provided. In the position shown in Figure 1, the piston 18 penetrates a bore in a plate 21 supporting the device, so that the undercut groove 19 on the opposite side of the plate can be held by a T-nut (not shown), thereby locking the side slide 4 in the welding position. Reference numeral

[0045] 1 Counter-tool

[0046] 2 metallic contact parts

[0047] 2 metallic contact parts

[0048] 3 Welding room

[0049] 4 first side shifter

[0050] 4, 5 side shifters

[0051] 6, 7 upper contact surface section

[0052] 8, 9 lower contact surface section

[0053] 10 second pivot joint

[0054] 11 first pivot joint

[0055] 11 first pivot joint

[0056] 12 first levers

[0057] 12, 17 Knee lever

[0058] 13 Adjustment device

[0059] 15 carriers

[0060] 16 linear drives

[0061] 16 Linear drive

[0062] 17 second levers

[0063] 18 pistons

[0064] 18, 19 Locking device

[0065] 19 undercut groove

[0066] 20 stationary elements

Claims

P a t e n t a n s p r ü c h e 1. Ultrasonic welding device for welding metallic materials, such as welding stranded wire, comprising a welding chamber (3) for receiving the materials to be welded together, a sonotrode with a first sealing surface, a counter tool (1) with a second sealing surface, and at least one first side slide (4) with a first contact surface (6, 8), wherein the welding chamber (3) is bounded at least by the first and second sealing surfaces and the first contact surface (6, 8), wherein the first sealing surface is movable relative to the second sealing surface in a welding direction towards and away from each other, and the first contact surface (6, 8) is movable relative to the first sealing surface and relative to the second sealing surface, characterized in that a drive device is arranged and designed such that the drive device controls the relative movement of the first contact surface (6,8) opposite the second sealing surface both in a transverse direction perpendicular to the welding direction and in the welding direction.

2. Ultrasonic welding device according to one of the preceding claims, characterized in that the ultrasonic welding device is provided for welding strands with a metallic contact part (2), wherein the welding chamber (3) has a lower section which is provided for receiving the metallic contact part (2) and an upper section which is provided for receiving the strand, wherein the first contact surface (6, 8) has a first contact surface section which limits the upper section of the welding chamber and a second contact surface section which limits the lower section of the welding chamber, wherein the first contact surface section and the second contact surface section are arranged perpendicular to each other.

3. Ultrasonic welding device according to one of the preceding claims, characterized in that the drive device is configured and designed such that the first contact surface (6) can be moved back and forth on a circular path between a welding position in which the first contact surface limits the welding space and an opening position in which the first contact surface does not limit the welding space.

4. Ultrasonic welding device according to one of the preceding claims, characterized in that the drive device has a toggle lever (12, 17) with comprising a first and a second lever (17), wherein the first lever (12) is attached at one end to a stationary element (20) by means of a first pivot joint which allows the first lever (12) to rotate about a first axis of rotation, and at its other end to the second lever (17) by means of a second pivot joint (10), wherein the second pivot joint (10) allows the second lever (17) to rotate about a second axis of rotation which is arranged parallel to the first axis of rotation, wherein the second lever (17) is connected at its end opposite the second pivot joint (10) to the first side slider (4), wherein a linear drive element is operatively connected to the toggle lever (12, 17).

5. Ultrasonic welding device according to claim 4, characterized in that the linear drive element is in operative connection with the second lever (17), wherein preferably the linear drive element is connected to the second lever (17) via a connecting element which provides a positive locking connection between the linear drive element and the second lever in the welding direction and allows a relative movement between the linear drive element and the second lever perpendicular to the welding direction.

6. Ultrasonic welding device according to claim 4 or 5, characterized in that the first side slide (4) is movable back and forth between a welding position and an opening position, wherein in the welding position the toggle lever (12, 17) is oriented such that a force applied perpendicularly to the first contact surface (6, 8) is not transmitted to the linear drive element, wherein the first and the second lever (17) enclose an angle β with each other, wherein preferably the angle β in the opening position is less than 170° and increases during movement towards the welding position, wherein particularly preferably the angle β in the welding position is greater than 170° and preferably 180° or greater than 180° 7. Ultrasonic welding device according to one of claims 4 to 6, characterized in that the first lever (12) or the second lever (17) has lever elements connected to each other via a connecting device, wherein the connecting device allows an adjustment of the relative position between the two lever elements, wherein preferably the connecting device is a threaded rod with two threaded sections with different Thread pitches are those that engage in corresponding threaded holes which are incorporated into the lever elements.

8. Ultrasonic welding device according to one of the preceding claims, characterized in that a second side slider with a second contact surface is provided, wherein the welding chamber (3) is also limited by the second contact surface.

9. Ultrasonic welding device according to claim 8, characterized in that the drive device is arranged and designed such that it moves the first side slider (4) and the second side slider simultaneously both in the welding direction and in a direction perpendicular to the welding direction, wherein preferably the first and the second contact surface are arranged parallel to each other in each position.

10. Ultrasonic welding device according to one of the preceding claims, characterized in that at least one section of the first contact surface (6, 8) encloses an angle θ with the first sealing surface and the drive device is designed such that in every position of the side slide the section with the first sealing surface encloses the same angle 5.

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