WO2006029835A1

WO2006029835A1 - A welding device

Info

Publication number: WO2006029835A1
Application number: PCT/EP2005/009869
Authority: WO
Inventors: Erich Jentschmann; Dietmar Heil
Original assignee: Jentschmann Ag Zürich
Priority date: 2004-09-14
Filing date: 2005-09-14
Publication date: 2006-03-23

Abstract

The ultrasound welding device (1) for welding overlapping sheet formations (65a, 65b) comprises a continuously operable roller sonotrode (13) and at least one guide wheel (59a, 59b) which is arranged laterally of the roller sonotrode (13). During the welding the sheet formations (65a, 65b) are guided by a guide wheel (59a, 59b) which rotates with approximately the same peripheral speed as the roller sonotrode (13), wherein the tendency for wave formation with the welded sheet formations (65a, 65b) is minimal.

Description

A welding device

The subject-matter of the invention is a welding device, a method for welding overlapping sheet formations as well as subjects manufactured according to this method.

Ultrasonic welding is a joining technique with which e.g. thermoplastic or metallic subjects are connected to one another by supplying energy in the form of ultrasound or of high- frequency mechanical oscillation. A sonotrode which presses a first subject against a second subject is excited into oscillation in the ultrasonic range. By way of the transmission of the movement energy into the region of the border surface of both subjects, local frictional heat is produced which softens or melts the surfaces of the subjects and connects them to one another.

Ultrasonic welding technology amongst other things is used for connecting thermoplastic films or fabrics. Apart from devices for the cyclic welding with which the high-frequency energy is transmitted in a pulsed manner by way of a die onto the subjects to be connected, ultrasonic welding devices for the continuous connection of thermoplastic films are already known. With this, the sonotrode is designed in the shape of a roller. The films to be connected are continuously moved between the rotating sonotrode wheel and an anvil, preferably a press wheel which is rotated synchronously in the opposite rotational direction, wherein a welding seam is formed which holds the two films together. A part of the welding device with the sonotrode and the press wheel may be moved relative to the stationarily held films for joining-together larger subjects or films.

Many parameters such as e.g. the material of the films to be connected, the forward feed speed, the gap width between the sonotrode and the press wheel, the shaping and size of the press wheel, the pressing pressure of the sonotrode and the power supplied to the sonotrode influence the quality of the seam to be formed. The evaluation of suitable parameter constellations with continuously operated ultrasonic welding installations is unequally more difficult than with cycled ones. Furthermore, until now only relatively narrow welding seams could be formed which were insufficient for various applications.

One disadvantage of such conventional, continuously operated welding installations lies in the fact that fluctuation of quality of the formed seams may occur. Such seams in particular may have weak points at which the films are insufficiently welded to one another, but also regions, where the films e.g. are damaged or destroyed as a result of too great a development of heat. An excessive development of heat may effect a local flowing of the films to be connected. In particular polymer sheet formations such as e.g. PVC films have the tendency to shrink or to draw together under the effect of heat. On advancing the films or on rolling the roller sonotrode on the films during the welding procedure, tensile, compressive and shear forces may lead to inhomogeneities, in particular to the formation of waves in the region of the welding seam.

It is the object of the present invention to provide a continuously operable ultrasonic welding device with means for preventing or minimising the formation of waves, a method for its operation as well as subjects manufacturable according to this method.

According to a first embodiment of the invention, these objects are achieved by a welding device and a method for operating a welding device as well as by subjects, according to the preamble of the patent claims 1 , 8 and 10.

The ultrasound welding device according to the invention and the method according to the invention are based on an improved guiding of the sheet formations to be welded, relative to the welding head or vice-versa.

By way of guide wheels which are arranged directly or at a minimal lateral distance to the motorically actively driven roller sonotrode and/or to the preferably likewise motorically actively drivable counter-press wheel, one creates a transition region which is laterally adjacent to the welding zone, with similar conditions as prevail in the welding zone. Depending on the design, the guide wheels may be driven with the same or similar peripheral speed as the roller sonotrode or the press-wheel. Additional auxiliary wheels press the sheet formations laterally of the roller sonotrode against the associated guide wheels by way of a spring force which may be preferably set or adjusted. The auxiliary wheels may be lifted again from the sheet formations by way of a pneumatic drive. The auxiliary wheels may be designed as passive runners or be actively drivable. These precautionary measures counteract the formation of waves and creases in that they minimise the tensile, compressive (transverse) or shear forces in the region of the freshly formed, still soft and not hardened welding seam, and adapt the pressing pressure to that in the welding zone.

For an improved guiding of the sheet formations one may attach different, easily exchangeable guiding apparatus in the region of the welding head. On connecting, hemming and depositing reinforcement strips these assume the exact positioning and supply of the welding material or adhesive material to the welding zone

On bonding, adhesive strips, in particular double-sided, single-ply or multi-ply adhesive strips which may be activated by way of the effect of heat and/or pressure may likewise be positioned and guided by guiding apparatus. Supplementing this, one may provide further measures in order to favour the manufacture of high-quality, uniform welding seams without slack and without the formation of waves, e.g. the [closed-loop] control of the welding power of the roller sonotrode in dependence on welding parameters and/or the widening of the welding zone in which welding energy may be supplied the sheet formations and/or a subsequent treatment of the weld seam directly after its creation, e.g. by cooling, pressing, stretching etc..

The welding head in a preferred embodiment is arranged in a travelling manner along a long operating table so that only the length of the table essentially limits the length of a seam manufacturable in one working passage.

The travelling speed of the welding head as well as the rotation speeds of the roller sonotrode and of the counter-press roller may be set or controlled independently of one another.

Preferably the travelling speed is set as an overriding variable and from this the rotation speeds for the roller sonotrode and the counter-press roller are computed with a presettable ratio of the two peripheral speeds according to instructions which are stored in a control program. It has been shown to be particularly advantageous to let the sonotrode rotate with a peripheral speed whose magnitude is a little larger than that of the advance speed of the welding head, and for one to be selected as a ratio of the peripheral speeds.

The setting of the individual speeds as well as the surface structure of the sonotrode may influence the quality of the seam, in particular its appearance. The measurement and/or programming and/or [open-loop] control and/or closed-loop control of various welding parameters such as e.g. welding energy, oscillation amplitude of the sonotrode, rotation speeds of the sonotrode and of the pressure roller, the travelling speed of the welding head, the gap width between the sonotrode and the press roller etc. may be effected in a manner such that an optimal bonding is possible for different subjects or subject combinations. Data or welding parameters for various applications with different materials and material qualities may be stored in a memory in a non-volatile manner, and when required, e.g. may be called up again for example in a menu- controlled manner or may be used for setting the welding device. In particular, such data or welding parameters for the start phase and the end phase of the seam formation may differ from that of the phase lying between these. By way of the closed-loop control of the welding however one may prevent the films to be connected from melting in an uncontrolled manner and the formation of aggressive or toxic vapours. Furthermore the welding device according to the invention has a low energy consumption. Power peaks may be avoided thanks to the closed-loop control in real time. One may also prevent changes in certain welding parameters during the welding procedure from leading to a change of the seam quality.

As a rule the sonotrode wheel and the counter-press roller which cooperates with the sonotrode wheel in a roller-like manner may be arranged infinitely with regard to space, thus for example next to one another or above one another. Advantageously the roller sonotrode is arranged below the press roller or the counter-press roller in a manner such that the sonotrode axis relative to the press roller axis is displaced offset in the transport direction of the sheet formation to be welded or opposite to the travel direction of the roller sonotrode and press roller. The contact location, press location or welding location where the sheet formations are pressed between the two rollers or where the largest part of the welding energy is transmitted onto the sheet formation thus lies in front of and below the apex of the sonotrode wheel. On welding, the sheet formations continue to lie on the sonotrode wheel directly after the welding location. The peripheral speed of the sonotrode wheel is preferably the same size or slightly greater than the advance speed of the welding head. This effects a stretching and/or prevents a shrinkage and wave formation of the freshly welded sheet formation, which is softened in the region of the weld seam. This effect is additionally encouraged by the oscillation of the peripheral surface of the sonotrode.

Alternatively in place of a counter-press roller one may also design a counter press belt which runs around several rollers and partially wraps around the sonotrode wheel. The sheet formations in this case are welded in a two-dimensional (flat) region between the sonotrode wheel and the counter-press belt. By way of the two-dimensional (flat) formation of the welding, the danger of a local overheating and shrinkage of the welded material is reduced. Furthermore, the efficiency is improved and the energy consumption is lower.

The pressing or compressing and the simultaneous cooling of the seam after its creation is effected in a continuous manner directly subsequent to the seam formation location at the welding head. A pressing and cooling device arranged downstream of the welding head and able to be travelled at the same speed as this welding head comprises an upper and a lower heat-conducting pressing and cooling belt. Both cooling belts may e.g. be designed as endless steel belts and may be wrapped around several press and deflection rollers analogously to the tracks of a tracked vehicle, said rollers in each case being rotatably mounted in each case on a coolable mounting^earing device. One of these may be preferably motorically driven. By way of e.g. a pneumatic force, the mounting/bearing devices may be subjected to a predefined or settable force in a manner such that the sheet formations lying between the cooling belts are pressed or pushed together. The press rollers of the two mounting/bearing devices are arranged offset to one another in the running direction of the cooling belts so that on pressing them together, they at least partly mesh into one another and at the same time the cooling belts deform in a wave-like manner. By way of this, the sheet formations pressed together between the cooling belts are slightly stretched or extended in the region of the freshly formed welding seam. Simultaneously the cooling device leads away the heat e.g. by way of thermal conduction and/or by way of an air or water cooling. The welding seam may solidify without slack.

The sheet formations become excessively heated at the application location of the welding seam in the edge region. Additional measures may prevent a local shrinkage of the sheet formations. One possibility lies in fixing the sheet formations to be welded along the starting edge and/or the weld seam e.g. by way of a pneumatically operable clamping device, and retracting the cooling belts by about one to three millimetres shortly after the beginning of the welding (e.g. as soon as 10 cm of the welding seam has been formed) or by way of suitably braking them.

Alternatively to revolving endless cooling belts these may also be anchored at one side e.g. at the front end of the operating table by way of a clamping body. Each of the cooling belts is tensioned around at least a part of the press or deflection rollers analogously to the previous description, and is wound around a wind-up or wind-off roller rigidly connected to the associated bearing/mounting device. A spring, a motor or another drive element produces a torque acting on the wind-off roller which keeps the associated cooling belt tensioned between the anchoring on the operating table and the wind-off roller, independently of the position of the cooling device. For stretching the welding location at the freshly formed weld seam, the clamping body on which the belts are anchored may be retracted by the corresponding amount.

In a further alternative design, the lower cooling belt is not wound onto a wind-off roller but is led around the sonotrode wheel arranged at the bottom by way of further deflection rollers, and is fixed on the other end of the operating table.

Large seam lengths with uniform quality may be manufactured without interruption with the device according to the invention, in particular also in the starting region and end region.

The device and the method are suitable for welding and/or joining together fabric-like or film-like subjects or sheet formations such as thermoplastic films or tarpaulin [covers] or of fabrics coated with thermoplasts such as PVC. Uncoated substances such as e.g. acrylic which is widely used in the manufacture of canopies may be connected without any problem by way of hot-melt adhesives. Possible applications for example are the manufacture of films, canopies, tarpaulin [covers], pieces of clothing, etc.

Even if the sheet formations have large dimensions and/or the joint locations or weld seams are very long they may be regularly manufactured with a constant quality. They may be manufactured with a uniformly high strength and/or good sealing properties over the whole seam length, thus also in the edge regions.

The seam widths may be significantly larger than was possible until now, i.e. larger than about 11 mm. New applications open up on account of this. In only one passage one may create connections for which previously one would have required two or several successive welding procedures. With the method according to the invention and the device according to the invention one may carry out high-quality welding and bonding in an inexpensive and efficient manner.

According to a second embodiment of the invention, these objects are achieved by a welding device and a method for operating a welding device as well as by subjects, according to the preamble of the patent claims 11, 17 and 20.

The ultrasound welding device according to the invention and the method according to the invention are based on the consideration that with a controlled guiding and with a targeted stretching of the still soft weld seam directly after the welding location, or with a controlled transport of the freshly welded sheet formations, one may prevent or reduce a wave formation in the region of the weld seam.

By way of guide wheels which are arranged directly or at a minimal lateral distance to the motorically actively driven roller sonotrode and/or to the preferably likewise motorically actively drivable counter-press wheel, one creates a transition region which is laterally adjacent to the welding zone, with similar conditions as prevail in the welding zone. Depending on the design, the guide wheels may be driven with the same or similar peripheral speed as the roller sonotrode or the press-wheel. Additional auxiliary wheels press the sheet formations laterally of the roller sonotrode against the associated guide wheels by way of a spring force which may be preferably set or adjusted. The auxiliary wheels may be lifted again from the sheet formations by way of a pneumatic drive. The auxiliary wheels may be designed as passive runners or be actively drivable. These precautionary measures counteract the formation of waves and creases in that they minimise the tensile, compressive (transverse) or shear forces in the region of the freshly formed, still soft and not hardened weld seam, and adapt the pressing pressure to that in the welding zone.

On bonding, adhesive strips, in particular double-sided, single-ply or multi-ply adhesive strips which may be activated by way of the effect of heat and/or pressure may likewise be positioned and guided by guiding apparatus.

Supplementing this, one may provide further measures in order to favour the manufacture of high-quality, uniform weld seams without slack and without the formation of waves, e.g. the [closed-loop] control of the welding power of the roller sonotrode in dependence on welding parameters and/or the widening of the welding zone in which welding energy may be supplied the sheet formations and/or a subsequent treatment of the weld seam directly after its creation, e.g. by cooling, pressing, stretching etc..

The travelling speed of the welding head as well as the rotation speeds of the roller sonotrode and of the counter-press roller may be set or controlled independently of one another. Preferably the travelling speed is set as an overriding variable and from this the rotation speeds for the roller sonotrode and the counter-press roller are computed with a presettable ratio of the two peripheral speeds according to instructions which are stored in a control program. It has been shown to be particularly advantageous to let the sonotrode rotate with a peripheral speed whose magnitude is a little larger than that of the advance speed of the welding head, and for one to be selected as a ratio of the peripheral speeds.

The pressing or compressing and the simultaneous cooling of the seam after its creation is effected in a continuous manner directly subsequent to the seam formation location at the welding head. A pressing and cooling device arranged downstream of the welding head and able to be travelled at the same speed as this welding head comprises an upper and a lower heat-conducting pressing and cooling belt. Both cooling belts may e.g. be designed as endless steel belts and may be wrapped around several press and deflection rollers analogously to the tracks of a tracked vehicle, said rollers in each case being rotatably mounted in each case on a coolable mounting/bearing device. One of these may be preferably motorically driven. By way of e.g. a pneumatic force, the mounting/bearing devices may be subjected to a predefined or settable force in a manner such that the sheet formations lying between the cooling belts are pressed or pushed together. The press rollers of the two mounting/bearing devices are arranged offset to one another in the running direction of the cooling belts so that on pressing them together, they at least partly mesh into one another and at the same time the cooling belts deform in a wave-like manner. By way of this, the sheet formations pressed together between the cooling belts are slightly stretched or extended in the region of the freshly formed weld seam. Simultaneously the cooling device leads away the heat e.g. by way of thermal conduction and/or by way of an air or water cooling. The weld seam may solidify without slack.

The sheet formations become excessively heated at the application location of the weld seam in the edge region. Additional measures may prevent a local shrinkage of the sheet formations. One possibility lies in fixing the sheet formations to be welded along the starting edge and/or the weld seam e.g. by way of a pneumatically operable clamping device, and retracting the cooling belts by about one to three millimetres shortly after the beginning of the welding (e.g. as soon as 10 cm of the weld seam has been formed) or by way of suitably braking them.

Finally, the above objects are also achieved according to a third embodiment of the invention by a welding device and a method for operating a welding device as well as by subjects, according to the preamble of the patent claims 21, 33 and 37.

The ultrasound welding device according to the invention and the method according to the invention are based on the knowledge that the wave formation to a great extent may be attributed to the shrinkage of polymer materials as a result of excessive heating, and that the extension and pressing of such materials during the cooling or solidifying counteracts a permanent shrinkage.

This is particularly the case of these forces are changed during the cooling.

The pressing or compressing and the simultaneous cooling of the seam after its creation is effected in a continuous manner directly subsequent to the seam formation location at the welding head. A pressing and cooling device arranged downstream of the welding head and able to be travelled at the same speed as this welding head in a preferred embodiment comprises an upper and a lower heat-conducting pressing and cooling belt. Both cooling belts may e.g. be designed as endless steel belts and may be wrapped around several press and deflection rollers analogously to the tracks of a tracked vehicle, said rollers in each case being rotatably mounted in each case on a coolable mounting/bearing device. One of these may be preferably motorically driven. By way of e.g. a pneumatic force, the mounting/bearing devices may be subjected to a predefined or settable force in a manner such that the sheet formations lying between the cooling belts are pressed or pushed together. The press rollers of the two mounting/bearing devices are arranged offset to one another in the running direction of the cooling belts so that on pressing them together, they at least partly mesh into one another and at the same time the cooling belts deform in a wave-like manner. By way of this, the sheet formations pressed together between the cooling belts are slightly stretched or extended in the region of the freshly formed welding seam. Simultaneously the cooling device leads away the heat e.g. by way of thermal conduction and/or by way of an air or water cooling. The welding seam may solidify without slack. The sheet formations become excessively heated at the application location of the welding seam in the edge region. Additional measures may prevent a local shrinkage of the sheet formations. One possibility lies in fixing the sheet formations to be welded along the starting edge and/or the weld seam e.g. by way of a pneumatically operable clamping device, and retracting the cooling belts by about one to three millimetres shortly after the beginning of the welding (e.g. as soon as 10 cm of the welding seam has been formed) or by way of suitably braking them.

Supplementing this, one may provide further measures in order to favour the manufacture of high-quality, uniform welding seams without slack and without the formation of waves, e.g. the [closed-loop] control of the welding power of the roller sonotrode in dependence on welding parameters and/or the widening of the welding zone in which welding energy may be supplied the sheet formations and/or an additional guiding of the sheet formations to be welded in the region of the sonotrode subsequent, etc..

The setting of the individual speeds as well as the surface structure of the sonotrode may influence the quality of the seam, in particular its appearance. The measurement and/or programming and/or [open-loop] control and/or closed-loop control of various welding parameters such as e.g. welding energy, oscillation amplitude of the sonotrode, rotation speeds of the sonotrode and of the pressure roller, the travelling speed of the welding head, the gap width between the sonotrode and the press roller etc. may be effected in a manner such that an optimal bonding is possible for different subjects or subject combinations. Data or welding parameters for various applications with different materials and material qualities may be stored in a memory in a non-volatile manner, and when required, e.g. may be called up again for example in a menu- controlled manner or may be used for setting the welding device. In particular, such data or welding parameters for the start phase and the end phase of the seam formation may differ from that of the phase lying between these. By way of the closed-loop control of the welding however one may prevent the films to be connected from melting in an uncontrolled manner and the formation of aggressive or toxic vapours. Furthermore the welding device according to the invention has a low energy consumption. Power peaks may be avoided thanks to the closed-loop control in real time. One may also prevent changes in certain welding parameters during the welding procedure from leading to a change of the seam quality

The device and the method are suitable for welding and/or joining together fabric-like or film-like subjects or sheet formations such as thermoplastic films or tarpaulin [covers] or of fabrics coated with thermoplasts such as PVC. Uncoated substances such as e.g. acrylic which is widely used in the manufacture of canopies may be connected without any problem by way of hot-melt adhesives. Possible applications for example are the manufacture of films, canopies, tarpaulin [covers], pieces of clothing, etc. Even if the sheet formations have large dimensions and/or the joint locations or weld seams are very long they may be regularly manufactured with a constant quality. They may be manufactured with a uniformly high strength and/or good sealing properties over the whole seam length, thus also in the edge regions.

The processing speeds may be relatively high in comparison to conventional welding methods.

The invention is described in more detail by way of a few figures. With this there are shown in:

Figure 1 a schematic representation of an ultrasonic welding installation,

Figure 2 a longitudinal section of a welding device in the region of the sonotrode (without guide wheels and auxiliary wheels),

Figure 3 a principle schematic diagram of the device (without guide wheels and auxiliary wheels),

Figure 4a a schematic representation of a pressing and cooling device with an endless cooling belt on a welding installation (without guide wheels and auxiliary wheels),

Figure 4b a further pressing and cooling device with cooling belts which are held clamped on one side in a clamping device,

Figure 5 an arrangement of guide wheels and auxiliary wheels with a further welding device, seen from the side,

Figure 6 the arrangement of guide and auxiliary wheels from Figure 5, seen from the front,

Figure 7 an alternative arrangement of the sonotrode and press wheel. Figure 1 in a schematic representation shows an ultrasonic welding device 1 in a first design. The welding device 1 comprises the following elements (not a complete listing):

- A long operating table with a stable framing 5 of aluminium sections and a horizontal operating plate 7 which is divided centrally into two part plates 7a, 7b by way of a gap 9 running in the longitudinal direction.

An L-shaped or C-shaped carrier 1 1 or carriage or slide, which is displaceably guided on guide rails (not shown) in the longitudinal direction along the operating table 3.

A welding head with a wheel-like roller sonotrode, called sonotrode 13 for short, which is rotatably held on a sonotrode carrier 15 over the gap 9. The welding head may be lowered or lifted in settable positions or attitudes along a guide (not shown) formed on the upper arm 11a, e.g. by way of a pneumatic drive. If the sonotrode 13 rests on a subject the contact pressure or the contact force may be detected e.g. by way of a pressure sensor. The contact pressure, indicated in Figure 3 at "p" may thus be [open-loop] controlled and/or closed-loop controlled. The sonotrode according to the invention may have a significantly larger effective width than was possible until now, e.g. 12mm, 15mm, 20mm.

- An anvil in the form of counter-press roller or press roller 17 which is arranged parallel to the axis below the sonotrode 13 and serves as an abutment element for the subjects to be joined on pressing from the opposite side by way of the sonotrode 13. (Of course alternatively the anvil may be movable and the sonotrode position fixed. The anvil with some designs of the invention may also be a longitudinal rail arranged in the gap 9). The pressure roller 17 is rotatably mounted on a carriage (not shown) which is synchronously displaceable with the carrier 11 or is rotatably mounted on a press roller carrier 16 held on the lower arm l ib (Fig. 2) of the carrier 11. It projects from below into the gap 9. The periphery or roller surface of the press roller 17 projects beyond the upper side of the operating plate 7 or is arranged flush to this.

- Guide wheels 59 and auxiliary wheels 61 (Fig. 5 and Fig. 6) arranged laterally of the sonotrode wheel 13 and the press roller 17.

- A first drive 19 for displacing or travelling the carrier 11 at a speed V| in the longitudinal direction of the operating table 3, a second drive 21 (Fig. 3) for rotating the roller sonotrode 13 at a first surface speed v₂ and a third drive 23 for rotating the press roller 17 at a third speed v₃, wherein these drives 19, 21, 23 are preferably electrical servomotors. The first drive 19 may e.g. be fixedly arranged in the end region of the operating table 3, wherein an endless toothed belt connected to the carrier 11 or a similar transmission element may convert the rotational movement into a translation movement of the carrier 11 (no representation). The second drive 21 may e.g. be coaxially connected to the sonotrode 12 and drive this directly. Preferably it is arranged in the region of the sonotrode carrier 15 such that the rotational movement may be transmitted onto the rotation axis Al (Fig. 2) of the roller sonotrode 13 by way of gearing up or down. The third drive 23 may be actively connected to the press wheel 17 in an analogous manner.

- Generator electronics, called generator 25 for short (Fig. 3), for producing the high- frequency activation power for the excitation of the sonotrode 13. The generator 25 may comprise a power sensor 27 or a similar detection means which emits an analog or digital signal which corresponds to the electrical power consumption [P] of the generator 25.

- A main control, called control 29 for short, for the [open-loop] control and/or closed-loop control of the generator 25 in dependence on setting values or required or command variables and measured or control variables, hi particular, the control 29 is designed in a manner such that it may detect the power P' supplied by the generator 25 to the sonotrode 13 or (if information on the efficiency of the sonotrode is present, i.e. on the ratio of the power supplied to the subject by the sonotrode to the electrical power consumed by the sonotrode) the power delivered to the subject by the sonotrode 13 as a measured variable or control variable. Furthermore the control 29 comprises a preferably non-volatile memory 30 in which different combinations of welding parameters and/or further variables may be stored. Suitable data or alternatively data functions or courses dependent on time and position which favour or ensure the manufacture of high-quality seams with a uniform strength and sealedness may thus for example be stored for various combinations of subjects to be joined. A few examples of such data are cited hereinafter, wherein the possible value range is specified in square brackets:

- the welding power P" as a command variable as a percentage of the maximal welding power: 75% [50%...100%], wherein the maximal welding power may for example be 500W, 600W, 750W, 900W or IkW, regulating variable(s): amplitude A [amplitude A, pressure p] welding speed vj: O.lm/s [O.O5m/s...O.35m/s] - total welding duration: 5s [0.1s...10Os] total seam length: 4.9m [0.01m...2Om] lower and upper limit of the applicable range of the respective data set (as a % of the total seam length or of the total welding duration): 5%/95% [0%...N%/N%...100%], wherein N: [0...100] material thickness of the lower subject: 0. lmm [0.1 mm...10mm] material thickness of the upper subject: 0. lmm [0.1mm...10mm] type of necessary adhesive strip as an intermediate layer: 0 [0, 1, 2, ...100] (an allocation table with detail specifications such as description, layer thickness etc. may likewise be stored).

The control 29 for example may compute a suitable gap width s (Fig. 2) between the sonotrode 13 and the pressure roller 17 from such data. Alternatively this gap width s may also be set as a storable parameter. This gap width s may serve as a border value on welding or bonding (gluing) which may not be fallen short of. The control 29 monitors the gap width s or a measurable equivalent variable and may use this as an additional criteria for influencing e.g. the sonotrode amplitude or the speeds of one or more of the drives 19, 21, 23. With a particularly advantageous design of the invention, a distance sensor (no representation) which may e.g. be held on the lower side of the upper arm 1 Ia or on the sonotrode carrier 15 detects the distance to the upper side of the subjects to be joined just in front of the weld location. If the material thickness suddenly changes, thus for example on crossing a reinforcement strip or in the region of a seam, the welding parameters including the welding power may be automatically adapted and modified for this region according to a settable pattern.

A mains part for providing the energy supply in particular of the generator 25, the control 29 and the electrical drives 19, 21, 23 and, as the case may be, of further components which are operated with electrical energy.

An operating device 33 with operating elements 35 (e.g. a keyboard) and with a display 37 which are preferably designed for a menu-controlled operation.

A roller holder for accommodating an adhesive tape roller, said holder able to be easily assembled and removed again.

A continuously operable pressing and cooling device 43. Optionally, one or more easily exchangeable guide apparatus 51 (Fig. 1). A holding device (not shown) for one or more guide apparatus 51 is provided in the region of the welding head. For seaming one may e.g. use a guide apparatus 51 into which one edge of the sheet formation is bent over or inserted in a folded manner and may be clamped rigidly between two plates equipped with rollers. The clamping may be effected by way of spring force or by way of pressurised air. The deflection device (no representation) on the entry side ensures than with the travel of the carrier 1 1 , the material edge is continuously bent over and introduced into the clamping device in a positionally accurate manner. If the seam is bonded by way of a holt-melt adhesive, the guide apparatus 51 may additionally comprise a feed device (no representation) for the positionally-accurate introduction of a double- sided, single-layer or multi-layer adhesive tape 42 which may be activated by way of pressure and/or heat and which may be drawn from a supply roller 41. The adhesive tape 42 in contrast to conventional hot-melt adhesive methods may be exactly aligned before the adhesive effect begins due to the supply of energy by way of the sonotrode 13. With wide sonotrodes 12 one may form seams and margins with which the bonding (gluing) is uniformly distributed onto the whole width of the seam or margin. The heating is furthermore effected from the inside, thus at the border layers between the film or fabric and the adhesive tape. A damage or even destruction of the subject films on account of excess supply of heat from the outside may therefore be avoided. The same applies also to the supply and conveyor apparatus 51 for the reinforcement strips or for connecting film or fabric webs.

As is represented in Figures 4b and 7, the sonotrode axis Al lying at the bottom and the press roller axis A2 lying at the top and parallel to this may be arranged laterally offset to one another by an offset a. The offset a may lie in the range of a few millimetre up to a few centimetres, for example lcm or 2.5cm. In any case it is dimensioned such that the welding location Z or the centre of the welding region lies in front of the apex S of the sonotrode 13 seen in the transport direction T of the material to be welded 65. The material to be welded or the sheet formation thus after welding still lies a little bit on the rotating and oscillating sonotrode 13 (or alternatively on the press roller 17 if the press roller 17 lies at the bottom and the sonotrode 13 lies at the top) and is transported also by this sonotrode. This is particularly advantageous if the sheet formation 65 is greatly softened after welding, thus e.g. with sheet formations 65 of PVC. By way of the guided transport, the material to be welded 65 may cool somewhat on the sonotrode 13 without the action of further forces, before it is subsequently led to the pressing device 43. Even with greatly melting material to be welded 65 one may create smooth welding seams with a low slack and with a minimal formation of waves. It is further evident from Figure 7 that the sonotrode 13 and the press roller 17 may have different diameters. In particular the roller arranged at the bottom, thus e.g. the sonotrode 13 may have a larger diameter that the upper roller. Preferably the advance speed of the material to be welded 65 serves as a main variable or command variable for the computation of the rotational speeds of the sonotrode 13 and of the press wheel 17. The sonotrode 13 and the press wheel 17 preferably rotate synchronously with oppositely directed equal peripheral or surface speeds. If these surface speeds are somewhat smaller that the advance speed of the material to be welded 65, this effects a slight stretching of the material to be welded 65. This stretching may compensate a subsequent slight drawing- together and likewise contributes to the prevention of the formation of waves.

As is represented in the Figures 5 and 6, for an improved guiding and for helping to prevent the formation of waves on the welded materials, one may provide additional wheels. A first guide wheel 59a is rigidly fastened slightly distanced laterally of the sonotrode 13 on the same shaft coaxially to this. It has roughly the same diameter as the sonotrode 13 and rotates synchronously to the sonotrode 13 but is not in direct contact with this or coupled to this. A second guide wheel 59b is connected in an analogous manner to the shaft of the press wheel 17. It has roughly the same diameter as the press wheel 17 and may laterally bear on this and rotates synchronously with the press wheel 17. Alternatively the press wheel 17 may also be designed wider and assume the function of the guide wheel 59b. A rolling device comprises a significantly smaller, passive first auxiliary wheel 61a which on a spring-biased first toggle lever 63 a is held next to the sonotrode 13 on the sonotrode carrier 15 such that it is pressed by the spring force against the second guide wheel 59b. In an analogous manner a second auxiliary wheel 61 is held on a spring-biased second toggle lever 63b next to the press roller 17 and is pressed against the first guide wheel 59a.

Alternatively the guide wheels 59a, 59b may also be arranged on both sides of the sonotrode 13 or on both sides of the press wheel 17 on the respective drive shaft. It would likewise also be possible to design the guide wheels 59a, 59b smaller and to mount them on separately drivable shafts. By way of this it would be possible to produce shear forces in the region of the welding seam by way of slightly different peripheral speeds of the sonotrode 13 and of the guide wheels 59a, 59b.

Of course the positions of the sonotrode 13 and the press roller 17 - and thus also those of the guide wheel s 59a, 59b and of the auxiliary wheels 61a, 61b - may also be exchanged.

The press and cooling device 43 is arranged directly after the welding head seen in the transport direction T of the sheet formation 65 or opposite to the advance direction of the carrierl l. It may for example, as is schematically shown in Figure 4a, comprise a parallelepiped roller holder 45 of heat-conducting material with a press arm 46 which analogously to the sonotrode 13 and the sonotrode carrier 15 may be pneumatically adjustable or positionable in the vertical direction and impinged with pressure. Several rowed, small metal rollers as press rollers 47a with good heat-conducting properties are mounted in a freely rotatably manner on the roller holder 45 on the lower longitudinal side of the roller holder 45 at small mutual distances to one another along a straight or a waved line. A deflection roller 47b with a larger diameter is rotatably and preferably motorically drivably held in each case on the two narrow sides in each case by way of a fastening and clamping device (not shown), wherein these deflection rollers 47b project laterally from and above the roller holder 45. An endless press and cooling belt 49 is tensioned around the press rollers 47a and the deflection rollers 47b in a manner similar to the track of a tracked vehicle, which preferably has good heat conducting properties, a high mechanical stability and a high flexibility, e.g. a steel belt. In an analogous manner a counter-press belt or cooling belt may be arranged flush with the upper side of the operating plate 7 (no representation) on the opposite side, thus in the gap 9. The press device 43 may additionally be cooled with pressurised air or with another means.

Alternatively the press and cooling device may also be designed according to Figure 4b.

The front ends of the upper cooling belt 49a and of the lower cooling belt 49b are rigidly clamped on a clamping body 67. This is held displaceably along a guide (arrow B) and/or rotatably about a rotation axis (not shown), at the front end of the operating table by way of a drive (not shown). By way of such a movement of the clamping body 67 the cooling belts 49a, 49b may be retracted or tensioned in the region of the cooling device by a slight amount of e.g. one to five millimetres in the transport direction T of the sheet formation 65, in order to effect a stretching of excessively shrinked welding locations. After the stretching procedure, the clamping body 67 may be moved back into the initial position or location. Each of the cooling belts 49a, 49b bears at least on a part of the associated press rollers 47a and deflection rollers 47b. The respective other ends of the cooling belts 49a, 49b are wound onto wind-up or wind-off rollers 69. The wind-off rollers 69 (only the upper wind-off roller 69 is visible in Figure 4b) are rotatably mounted on displaceable carriers 11 or on the upper arm 11a and the lower arm 1 Ib. With each of the wind-up rollers 69 there is provided a motor or another drive element (not represented) for producing a torque. By way of this, the cooling belts 49a, 49b may be held tensioned between the anchoring on the operating table 3 or on the clamping body 67 and the associated wind-off roller 69, independently of the position of the cooling device. For stretching the welding location in the edge region of the freshly formed weld seam, the clamping body 67 on which the belts 49 are anchored may be retracted against the tension force of the wind-off roller drive by a settable length. The press rollers 47a on the upper and/or lower roller holder 45 or cooling or metal bodies 45 may have different sizes and/or levels of rotational axes. In Figure 4b larger press rollers 47a are arranged above the upper cooling belt 49a at regular distances L. In each case two smaller press rollers 47a with a slightly higher axis level are rotatably mounted on the roller holder between in each case two larger press rollers 47a . On the lower roller holder 45 lower press rollers 47a are rotatably mounted offset to the larger upper press rollers 47a by half the distance L in the transport direction. The roller holder 45 with the press rollers 47a during welding may be displaced synchronously with the carrier 11 along the operating table 3. Furthermore they may be moved vertically to the welding direction or to the operating table 3 so that their mutual distance becomes larger or smaller. The movements of the roller holder 45 relative to the operating table 3 are represented in Figure 4b by fourfold arrows F. For inserting or removing the sheet formations 65a, 65b to be welded or the welded sheet formation 65 - these are represented in Figure 4b as dotted bold lines - the press arm 46 with the upper roller holder 45 is lifted. For cooling and smoothing the freshly formed weld seam during the welding process, the driven press arm 46 presses the upper roller holder 45 downwards such that the freshly welded sheet formation 65 is pressed together between the cooling belts 49a, 49b in the region of the press rollers 47a. Due to the press rollers 47a which are arranged in an offset manner, a wave shape is imposed on the cooling belts 49a, 49b. By way of this deformation and by way of the advance movement of the cooling device during the welding, compressive, tensile and shear forces act on the sheet formation 65 in the region of the freshly formed weld seam. These counteract a wave formation of the weld seam. In a preferred embodiment of the welding device these forces may be influenced by way of setting, controlling or regulating the clamping force or the torque of the wind-off rollers 69 and/or the pressing pressure of the press arm 46.

With a further alternative embodiment, the lower cooling belt is not wound onto a wind- off roller but by way of further deflection rollers 47b is led around the lower arranged sonotrode wheel 13 and fixed at the other end of the operating table 3.

With a further design of the welding machine, as may be used e.g. for manufacturing smaller subjects such as rain clothing, the carrier 1 1 is stationary with the welding head, thus is not movable with respect to the operating table 3. The operating table may therefore be designed considerably shorter. The material to be welded may e.g. be led manually through the welding location. In this manner one may create seams which are shaped in any manner. At the same time the welding speed may be influenced via a foot control or another input means in a manner similar to a sewing machine. Additionally a picture sensor, e.g. a sensor as is used with an optical mouse, may detect the amount and/or direction of the movement of the material to be welded and the measuring variable may be taken into account as a further parameter on control of the welding power.

The individual devices or measures for preventing the formation of waves with welded seams may be applied individually or in any combination with one another. In particular they may be applied with welding machines having a controllable or regulatable welding power or without this.

Claims

1. A welding device (1) for welding overlapping edge regions of textiles and/or non-textile sheet formations (65a, 65b) for producing an undetachable connection seam, comprising a drivable roller sonotrode (13) rotatably mounted on a carrier (11) and an anvil arranged opposite the roller sonotrode (13), wherein

the roller sonotrode (13) and the anvil may be pressed against one another by way of a force,

the carrier (11) with the roller sonotrode (13) may be travelled or displaced relative to the sheet formations, or the sheet formations relative to the carrier (11) with the roller sonotrode (13),

the distance between the roller sonotrode (13) and the anvil (17) may be changed and

the sheet formations (65a, 65b) may be pressed together between the roller sonotrode (13) and the anvil and may be joined together by way of introducing ultrasound oscillations via the sonotrode (13),

characterised in that seen in the transport direction (T) of the sheet formations (65a, 65b) relative to the roller sonotrode (13), at least one drivable guide wheel (59a, 59b) is arranged laterally of the roller sonotrode (13).

2. An ultrasonic welding device (1) according to claim 1, characterised in that a roller device is provided for the guide wheel (59a, 59b), wherein the guide wheel (59a, 59b) and the roller device may be pressed against one another by a force.

3. A device according to claim 2, characterised in that the roller device comprises an auxiliary wheel (61a, 61b), wherein the sheet formations (65a, 65b) may be pressed together between the guide wheel (59a, 59b) and the auxiliary wheel (61a, 61b).

4. A device according to claim 3, characterised in that the auxiliary wheel (61a, 61b) is rotatably mounted on a spring-biased lever which is pivotable about a pivot axis.

5. A device according top one of the claims 1 to 4, characterised in that at least one of the guide wheels (59a) is arranged coaxially to the roller sonotrode (13) and may be driven synchronously with this.

6. A device according to one of the claims 1 to 5, wherein the anvil comprises a press roller (17), characterised in that at least one of the guide wheels (59b) is arranged coaxially to the press roller (17).

7. A device according to claim 6, characterised in that the press roller (17) is designed as a guide wheel (59b) which has a larger width that the roller sonotrode (13) and projects beyond this on one or on both sides in the axial direction.

8. A method for welding overlapping edge regions of textile and/or non-textile sheet formations (65a, 65b) for producing an undetachable connection seam, wherein the sheet formations (65a, 65b) are led through between a rotating roller sonotrode (13) excited into ultrasonic operation, and an anvil, or the roller sonotrode (13) mounted on a displaceable or travelling carrier (11) rolls on the sheet formations (65a, 65b), and with this, the sheet formations are welded to one another, characterised in that at least one guide wheel (59a, 59b) arranged next to the roller sonotrode (13), during the welding is driven with a peripheral speed which is equal or similar to that of the roller sonotrode.

9. A method according to claim 8, characterised in that the sheet formation or sheet formations (65a, 65b) during the welding are guided by the rotating guide wheel (59a, 59b).

10. Subjects manufactured with a method according to one of the claims 8 or 9, characterised in that the weld seams are formed in a uniform manner, and that the wave formation is minimal in the region of the weld seams.

1 1. A welding device (1) for welding overlapping edge regions of textiles and/or non- textile sheet formations (65a, 65b) for producing an undetachable connection seam, comprising a drivable roller sonotrode (13) which is rotatably mounted on a carrier (11) about an axis Ai, and an anvil arranged opposite the roller sonotrode (13) in the form of a press roller (17) rotatably mounted about an axis A₂, wherein

the roller sonotrode (13) and the press roller (17) may be pressed against one another by way of a force, the carrier (1 1) with the roller sonotrode (13) may be travelled or displaced relative to the sheet formations, or the sheet formations relative to the carrier (1 1) with the roller sonotrode (13),

the distance between the roller sonotrode (13) and the press wheel (17) may be changed and

the sheet formation (65a, 65b) may be pressed together between the roller sonotrode (13) and the press roller (17) and may be joined together by way of introducing ultrasound oscillations via the sonotrode (13),

characterised in that the axes Ai and A₂ of the roller sonotrode (13) and the press roller (17) are arranged offset to one another by a distance (a) in the transport direction (T) of the sheet formations (65a, 65b).

12. A welding device (1) according to claim 11, characterised in that the roller sonotrode (13) is arranged below the press roller (17).

13. A welding device (1) according to one of the claims 11 and 12, characterised in that the roller sonotrode (13) and the press roller (17) may be driven with opposite equal or similar peripheral speeds (\_\, v₂).

14. A welding device (1) according to one of the claims 11 to 13, characterised in that the diameter (Di) of the roller arranged at the bottom is larger than the diameter

(D₂) of the roller arranged at the top.

15. A welding device (1) according to one of the claims 11 to 14, characterised in that at least one drivable guide wheel (59a, 59b) is arranged laterally of the roller sonotrode (13) and/or of the press wheel (17) seen in the transport direction (T) of the sheet formations (65a, 65b) relative to the roller sonotrode (15).

16. A welding device (1) according to claim 15, characterised in that a roller device is provided for the guide wheel (59a, 59b), wherein the guide wheel (59a, 59b) and the roller device may be pressed against one another with a force.

17. A method for welding overlapping edge regions of textile and/or non-textile sheet formations (65a, 65b) for producing an undetachable weld seam with a device according to one of the claims 1 to 6, characterised in that the weld seam of the sheet formations (65a, 65b) directly subsequent to the welding location (Z) bears or lies on the rotating roller sonotrode (13) or on the rotating press roller (17), and is transported by this.

18. A method according to claim 17, wherein the carrier (11) is moved with a speed (vi) relative to the sheet formations (65a, 65b), characterised in that the peripheral speed (v₃) of the roller sonotrode (13) and/or the peripheral speed (v₂) of the press wheel (17) with regard to magnitude is larger or equal to the speed (vi) of the carrier (11).

19. A method according to claim 18, wherein the sheet formations (65a, 65b) lie on an operating table (3), characterised in that the sheet formations (65a, 65b) one the one hand are firmly held on the operating table (3) by way of a clamping device and on the other hand by the clamping between the roller sonotrode (13) and the press wheel (17), and that the weld seam is stretched by the movements of the roller sonotrode (13) and of the press wheel.

20. Subjects manufactured with the method according to one of the claims 17 to 19, characterised in that the weld seams are formed in a uniform manner and that the wave formation is minimal in the region of the weld seams.

21. A welding device (1) for welding overlapping edge regions of textiles and/or non- textile sheet formations (65a, 65b) for producing an undetachable connection seam, comprising a drivable roller sonotrode (13) rotatably mounted on a carrier (11) and an anvil arranged opposite the roller sonotrode (13), wherein

the carrier (1 1) with the roller sonotrode (13) may be travelled or displaced relative to the sheet formations, or the sheet formations relative to the carrier (1 1) with the roller sonotrode (13),

- the distance between the roller sonotrode (13) and the anvil may be changed and the sheet formations (65a, 65b) may be pressed together between the roller sonotrode (13) and the anvil and may be joined together by way of introducing ultrasound oscillations via the sonotrode (13),

characterised in that a press device (43) designed for the continuous pressing and cooling of weld seams is provided, and that this press device (43) is arranged downstream of the sonotrode (13) in the processing direction of the sheet formations (65a, 65b).

22. A welding device (1) according to claim 21, characterised in that the press device

(43) comprises at least one roller holder (45) on which several press rollers (47a) are rotatably mounted.

23. A welding device (1) according to claim 22, characterised in that the roller holder (45) is vertically movable on a press arm (46) relative to the sheet formations (65a,

65b), and/or may be subjected to pressure.

24. A welding device (1) according to one of the claims 22 or 23, characterised in that the roller holder (45) is held on the carrier (11) or on another part of the welding device (1), said part being stationary with respect to the carrier (1 1), in a manner such that it may be moved synchronously with the roller sonotrode (13) in the transport direction (T) of the sheet formations (65a, 65b).

25. A welding device (1) according to one of the claims 22 to 24, characterised in that the rotation axes of the press rollers (47a) mounted on the roller holder (45) are arranged along a straight or waved line.

26. A welding device (1) according to one of the claims 22 to 25, characterised in that not all press rollers (47a) have the same diameter.

27. A welding device (1) according to one of the claims 22 to 26, characterised in that one or more deflection rollers (47b) are rotatably mounted on the roller holder (45).

28. A welding device (1) according to one of the claims 22 to 27, characterised in that a cooling belt (49) at least partly or completely is wrapped around the arrangement of press rollers (47a) and deflection rollers (47b).

29. A welding device (1) according to claim 28, characterised in that at least one of the deflection rollers (47b) or press rollers (47a) is motorically drivable.

30. A welding device (1) according to one of the claims 22 to 27, wherein the carrier (11) may be travelled or displaced along an operating table (3), characterised in that a cooling belt (49) is held on the one hand on the operating table (3) or on a clamping device fastened on the operating table (3), and on the other hand is held in a tensioned manner on a wind-up or wind-off roller (69) which may be driven motorically or by spring force.

31. A welding device (1) according to claim 30, characterised in that the cooling belt (49) or the cooling belts (49a, 49b) are held on a motorically movable clamping body (67).

32. A welding device (1) according to one of the claims 22 to 31, wherein an upper or a lower roller holder (45) are provided, characterised in that on the upper roller holder (45) in each case between two press rollers (47a) projecting further downwards there are arranged two press rollers (47a) which project downwards to a lesser extent, and that on the lower roller holder (45) upwardly projecting press rollers (47a) are rotatably mounted in each case symmetrically between and below the press rollers (47a) of the upper roller holder (45) which projects downwards to a lesser extent.

33. A method for welding overlapping edge regions of textile and/or non-textile sheet formations (65a, 65b) for producing an undetachable welding seam, with a device according to one of the claims 1 to 13, characterised in that the sheet formations

(65a, 65b) are continuously welded to one another and the welding seam which is still soft is pressed and cooled.

34. A method according to claim 33, characterised in that the not yet solidified weld seam is pressed together between two cooling belts (49a, 49b) and/or are deformed and/or stretched in a manner which may be changed with respect to time.

35. A method according to claim 34, characterised in that a wave movement is imposed on the not yet solidified welding seam.

36. A method according to one of the claims 34 or 35, characterised in that a tensile force in the transport direction (T) of the sheet formations (65a, 65b) or opposite to the travel direction of the carrier (11) is exerted onto the cooling belts (49a, 49b).

37. Subjects manufactured with a method according to one of the claims 33 to 36, characterised in that the weld seams are formed in a uniform manner, and that the wave formation is minimal in the region of the weld seams.