WELDING MACHINE AND METHOD FOR THE THERMAL JOINING OF MATERIAL PANELS

Description

[0001] The present invention relates to an automatic welding machine for the thermal joining of material webs. The present invention further relates to a corresponding method for the thermal joining of material webs.

[0002] Welding machines for the thermal joining of material webs are generally known from the prior art. Such welding machines are used, for example, for the thermal joining or welding of thermoplastic material webs, such as plastic films or plastic or bitumen sheets, along their overlapping edge regions. In addition to a drive and at least one hot air unit or a heating wedge device, such welding machines have a carriage with one or more drive rollers, pressure rollers and / or support rollers, or a combination thereof. During the automatic welding process, the welding machine moves over a substantially flat (surface) on which the materials to be welded are welded together by the welding machine.In hot air welding, at least one hot air nozzle, located at the hot air outlet of a hot air unit of the welding machine, is guided between the overlapping edges of the materials to be welded in the welding area. This is done to plasticize the materials in the welding area through heat input. Subsequently, the plasticized areas of the materials are pressed together, creating a positive-locking connection, for example, by a pressure roller positioned downstream of the hot air nozzle in the working direction or direction of movement of the welding machine.

[0003] DE 20 2018 101 429 U1 discloses a welding machine for edge-welding of flat, thermoplastic materials with a housing, at least one drive and at least one hot air unit for heating the materials to be welded in a welding area, wherein the hot air unit is arranged on the welding machine in such a way that the hot air unit is rotatable about an axis aligned parallel to the transverse axis of the housing and is displaceable along this axis.

[0004] To increase stability, particularly against lateral tipping, ground-level hot air welding machines often have additional support wheels positioned as far apart as possible. An example of such a welding machine is described in EP 3 028 836 B1. In certain applications close to edges (parapets on roofs, etc.), these support wheels can obstruct the work or even prevent welding close to the edge. Therefore, in EP 3 028 836 B1, the two lateral support wheels are fixed together on a sliding platform and can thus be moved together to one side or the other of the machine, depending on the welding task.

[0005] According to the abstract, EP 3 028 836 B1 discloses a welding machine for edge-to-edge joining of overlapping material webs, which can be bonded together by heat and subsequent pressure, with a chassis on which at least rollers, a heating device, and at least one pressure roller are arranged. The heating device has a laterally projecting contact heating element that can be inserted between the edges of the material webs, and the chassis is driven by an electric motor arranged on a longitudinal leg of the chassis. According to the invention, the electric motor is designed as a brushless DC motor, and the reduction gear is designed as a planetary gear set, which are combined to form a drum drive motor. The DC motor is preferably a disc rotor motor.

[0006] The chassis in EP 3 028 836 B1 has a transverse leg that is adjustable relative to the longitudinal leg perpendicular to the direction of travel. This allows the entire transverse leg, including the non-driven rollers, to be laterally displaced relative to the longitudinal leg, on which the heating unit and the welding machine's control system are located and to which the drum drive motor, supporting the drive roller, is attached. The chassis can thus be modified in shape, from a first L-shaped variant, in which the transverse leg projects only to the left of the longitudinal leg in the direction of travel, to T-shaped variants, in which the transverse leg extends to the left and right beyond the longitudinal leg, and finally to a second L-shaped variant, in which the transverse leg projects only to the right of the longitudinal leg in the direction of travel.This advantageously allows welding close to the edge along upstands or bends of the bearing surface supporting the material sheets, i.e., for example, upwardly extending wall, door, shaft or parapet connections and flush end edges of flat roofs.

[0007] US 2008 / 0066870 A1 discloses a welding device for joining laterally overlapping sealing membranes.

[0008] US 5234 533 A discloses a portable hot air welding device for material webs.

[0009] US 6,187,122 B1 discloses a device for welding roof membranes with two welds and a method for its use.

[0010] Against this background, one objective of the present disclosure is to provide a further improved welding machine for the thermal joining of material webs. In particular, it would be desirable to provide a welding machine that is easy to operate and / or reduces maintenance requirements. Furthermore, it would be desirable to reduce manufacturing complexity.

[0011] The claimed subject matter is defined in the independent claims. Advantageous further developments are described in the dependent claims.

[0012] According to a first aspect of the present disclosure, a welding machine for thermally joining material webs, in particular for edge-to-edge joining of an overlapping upper material web with a lower material web, which can be joined together by means of a material bond under the influence of heat and subsequent pressure, is provided with: a heating device for at least partially heating the material webs to be joined in a joining area; a support frame with a housing; a pressure roller; at least two guide rollers; wherein the pressure roller and the guide rollers are arranged on the support frame and together with the support frame form a chassis, wherein the chassis has a longitudinal axis and a transverse axis perpendicular thereto, which span a chassis plane; wherein the heating device is movably arranged relative to the support frame by means of a telescopic extension in directions parallel to the transverse axis.The first caster and the heating device can be arranged on opposite sides of the chassis with respect to its longitudinal center. The telescopic extension has an axle, with the heating device fixedly attached to the axle of the telescopic extension. In the extended position, the axle is pulled out of the housing of the support frame, and in the retracted position, it is received by the housing of the support frame. The telescopic extension elements slide into one another. The heating device attached to the axle is designed as a hot air blower with a blower body containing an internal heating element, a fan for generating an airflow, and a hot air nozzle.

[0013] According to a further aspect of the present disclosure, a method for thermally joining material webs, in particular for edge-to-edge joining of an overlapping upper material web with a lower material web, which can be joined together by means of a material bond under the influence of heat and subsequent pressure, is proposed, comprising the steps of: providing a welding machine as described in the present disclosure; moving the heating device for at least partially heating the material webs to be joined in a joining area from a rest position to a working position by means of the telescopic extension; and thermally joining the material webs with the welding machine.

[0014] According to one aspect of the present invention, the welding machine for thermally joining material webs is proposed to provide a telescopic extension that can be extended in a direction parallel to the transverse axis. Movement with the telescopic extension is achieved by sliding the elements of the telescopic extension into one another. The heating element is fixedly mounted on the telescopic extension. Alternatively, a first telescopic extension can be provided for the heating element and a second telescopic extension for the first guide roller. The first of the two guide rollers can be moved in a direction parallel to the transverse axis by means of a telescopic extension. Similarly, the heating element can be moved in a direction parallel to the transverse axis by means of a telescopic extension. The telescopic extension is arranged and configured such that displacement of the heating element transverse to a longitudinal axis, i.e., transverse to a working direction, is prevented.The feed direction of the welding machine during the thermal joining of material webs is determined by the telescopic extension. The telescopic extension can have a receptacle fixed to or within the support frame of the welding machine, into which a shaft of the telescopic extension is (fully) inserted. This protects the shaft of the telescopic extension from the retracted position. The inventors recognized that the use of a telescopic extension is particularly advantageous in a welding machine for the thermal joining of material webs, as it reduces maintenance requirements. In the retracted position, the shaft of the telescopic extension is protected from contamination. Furthermore, corrosion of exposed elements is prevented. This reduces the need for repairs and increases the reliability of the welding machine.

[0015] Another advantage of the proposed solution is that, thanks to a telescopic extension projecting into the housing of the welding machine, additional components can be protected and located inside the housing. For example, a start switch for activating a drive of the welding machine can now be relocated inside the housing. This provides better protection for this additional component and further increases its reliability.

[0016] Another advantage of the proposed solution is that it allows for simple, ergonomic retraction. Furthermore, handling can be improved by eliminating the need for rigid axles protruding from the welding machine, thanks to the telescopic extension. This also increases workplace safety, as an operator cannot become trapped by a protruding element.

[0017] Within the scope of the present disclosure, a telescopic extension can be understood as a longitudinally extendable device comprising two or more coaxially nested elements. Each of the inner telescopic sections can be axially extended from the next larger section, which directly receives it. In other words, it is not merely a displacement of a rigid axis, but rather a sliding of elements into one another, whereby the longitudinal extension is reduced in the nested state.

[0018] The telescopic extension has an axle (also referred to as a shaft in the context of this disclosure), wherein the heating element is fixedly attached to the axle of the telescopic extension. In an extended state, the axle is pulled out of the housing of the support frame, and in a retracted state, it is received by the housing of the support frame, in particular, it is completely received or fully inserted into the housing of the support frame. Since the first heating element is fixedly attached to the axle of the telescopic extension, the movement thus occurs together with the axle of the telescopic extension. It is understood that the fixed connection can be released, for example, for maintenance purposes. The axle is then inserted back into the housing of the support frame and preferably completely received by it. This protects the axle from contamination and prevents corrosion. This reduces maintenance requirements.Particularly when operating the heating device in the retracted state, the susceptibility to repairs can be reduced, since the axis is retracted into the housing in the working position, i.e. during the welding process, and is therefore less susceptible to corrosion and dust accumulation.

[0019] The heating element can be arranged to rotate about an axis parallel to the transverse axis of the support frame. The heating element can be fixed axially and rotationally relative to the support frame in at least a first axial and rotational position, and can be fixed at least axially relative to the support frame in a second axial and rotational position that differs from the first. The axis can be an axis of the telescopic extension to which the heating element is attached. The first position can be a rest position of the heating element. In the rest position, the heating element can be fixed in a defined rest position both axially and with respect to rotation about the axis. The second position can be a working position of the heating element. In the working position, the axis with the heating element is primarily axially locked.However, rotational movement can still be enabled, at least over a limited angular range. This allows the working height of a heating device's outlet nozzle to adapt to a surface, or enables the flexible attachment of different outlet nozzles to a heating device. In the case of a heating wedge device, different heating wedges can be used flexibly.

[0020] The heating element is mounted on the support frame via a telescopic extension. The telescopic extension may have a bearing fixed to the support frame and a shaft. The shaft may extend between a first axial shaft end and a second axial shaft end along a shaft axis parallel to the transverse axis, with the second axial shaft end being the axial shaft end furthest from the housing. The shaft may be movably mounted on the bearing along its axis and rotatably about its axis. The heating element may be located on the shaft in a region of the second axial shaft end.

[0021] To fix the heating element in the first and / or second position, the shaft can be detachably fixed to the bearing by means of a locking device. The locking device can have at least one locking bolt, wherein the locking bolt is aligned in the direction of a locking axis that intersects the shaft axis perpendicularly and is movable in the direction of the locking axis, and wherein the shaft can be fixed in the first and / or second position by at least partial engagement of the locking bolt radially into the shaft axis. The locking bolt can be subjected to a spring force in the direction of the shaft axis. To allow limited rotational movement in the second position during operation, the shaft can have a longitudinal hole for engagement of the locking bolt.

[0022] A handle lever can be arranged at the second axial end of the shaft. The handle lever and the telescopic extension can be configured to allow manual rotation of the shaft around its axis. The handle lever and the telescopic extension can be configured to allow manual displacement of the shaft along its axis. The handle lever and the telescopic extension can be configured to allow manual release of the shaft from its mounting.

[0023] In a further development, a coaxial bolt can be accommodated inside the shaft of the telescopic extension, wherein the coaxial bolt extends at least partially through the shaft parallel to the shaft axis, wherein the coaxial bolt is movable in directions relative to the shaft axis, wherein the locking bolt can be brought at least partially (into engagement and / or) into engagement with the coaxial bolt at least at the first position and / or the second position, and wherein the locking bolt can be disengaged from the coaxial bolt by moving the coaxial bolt in a direction along the shaft axis relative to the shaft. In particular, the coaxial bolt can be designed such that the locking bolt can be disengaged from the coaxial bolt by a longitudinal movement of the coaxial bolt in the direction of the shaft axis.In other words, the locking of the shaft axis by the locking bolt can be released by the longitudinal movement of the coaxial bolt within the shaft axis. This allows the locking bolt to be actuated in a simple manner. Such a defined actuation of the locking bolt can preferably reduce mechanical stress and, for example, prevent the locked bolt from breaking. A further advantage can therefore be improved reliability.

[0024] The coaxial bolt can project beyond the second shaft end at one axial end, with the handle lever being located at this axial end of the coaxial bolt. A spring element is clamped between the handle lever and the second shaft end. A stop inside the shaft, in combination with a counter-stop on the coaxial bolt, limits the movement of the coaxial bolt along the shaft axis towards the second shaft end. The axial end of the coaxial bolt can be an extension of the coaxial bolt. In other words, the coaxial bolt is not necessarily formed in one piece. Optionally, the handle lever can be inclined at an acute angle to a plane with a normal parallel to the shaft axis.One advantage of this design is that the heating element (together with the axle) can be moved very easily and ergonomically using the handle at the axial end. This handle can also simultaneously be used to release the locking mechanism. Thus, the heating element can preferably be swung in and out with one hand.

[0025] The welding machine can have a drive unit. The drive unit can be coupled to a start-up switch, which is configured to provide an enable signal for the drive unit. The start-up switch is located inside the housing and is configured to be actuated by the telescopic extension retracting into the housing, in particular by a retracting shaft of the telescopic extension. An advantage of this design is that the switch is housed within the casing and is thus well protected from external influences. For example, the axis of the telescopic extension, when retracted, can actuate an electromechanical switch inside the casing, which transmits a signal to a control unit that can switch the drive (feed of the welding machine) on or off.Optionally, a delay can be provided so that the user can switch from a handle used to operate the telescopic extension to a guide rod for guiding the welding machine.

[0026] Alternatively or additionally, the first guide roller can be mounted on the support frame via a further telescopic extension. This additional telescopic extension for the guide roller can have a dovetail guide. This can be a second telescopic extension for the first guide roller. The heating unit can be mounted on the welding machine via a separate first telescopic extension, allowing for laterally adjustable movement. By mounting the first guide roller on the support frame via the telescopic extension, the width of a track can be adjusted. However, this does not involve moving an axle with both guide rollers. The second guide roller on the side opposite the frame can be fixed and non-movable. Preferably, the first guide roller can disappear completely into the frame when retracted, so that nothing protrudes laterally. This allows for welding close to the edge.One advantage of designing the telescopic extension for the caster as a dovetail guide can be that the telescopic extension can be mounted particularly smoothly even under a lateral load perpendicular to the extension direction, while simultaneously offering minimal play, which in turn promotes stability and guiding accuracy.

[0027] In a further development, the telescopic extension with the first guide roller can be configured so that, at least when the guide roller is at a minimal distance from the longitudinal center of the support frame and parallel to the transverse axis, it does not project beyond the support frame in a direction parallel to the transverse axis. The telescopic extension with the first guide roller can also be configured so that an axial extension end facing away from the longitudinal center is flush with the support frame. This allows for welding processes particularly close to the edges.

[0028] The welding machine can also have an adjustment device for setting the track of at least one of the guide wheels. An advantage of this design can be that it improves straight-line tracking. For example, an adjustment screw can be provided on a second guide wheel, which is opposite the telescopic extension and parallel to the transverse axis of the chassis, by means of which the track or straight-line tracking of the welding machine can be adjusted.

[0029] The advantages described above in detail for the first aspect of the invention apply accordingly to the other aspects of the invention.

[0030] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0031] Exemplary embodiments of the invention are shown in the following drawings and are explained in more detail in the following description. They show: Fig. 1 a perspective schematic representation of a ground-level welding machine in a working position; Fig. 2 another perspective schematic representation of the ground-level welding machine made of Fig. 1 in a resting position; Fig. 3 a front view of the welding machine made of Fig. 1 in working position; Fig. 4 a front view of the welding machine made of Fig. 2 at rest; Fig. 5 a perspective schematic representation of a telescopic extension for a heating device for a welding machine in a retracted state, Fig. 6 a perspective schematic representation of the telescopic extension made of Fig. 5 in an extended state, Fig. 7 a side view of the telescopic extension made of Fig. 5 . in the retracted state and activation of a start switch with the start switch closed; Fig. 8 a side view of the telescopic extension made of Fig. 5 . in extended position with the start switch open; Fig. 9 a sectional view of the telescopic extension made of Fig. 7 along axis IX-IX; Fig. 10 a sectional view of the telescopic extension made of Fig. 7 along axis XX; Fig. 11 a perspective view of a welding machine with a telescopic extension for a guide roller; Fig. 12 a perspective view of a section of the welding machine with guide roller in an extended state; Fig. 13 a perspective view of a section of the welding machine with guide roller in a retracted state; Fig. 14 another perspective view of a section of the welding machine with guide roller in an extended state Fig. 12 ; Fig. 15 another perspective view of a section of the welding machine with guide roller in a retracted state Fig. 14 Fig. 16 shows a side view of a welding machine with a telescopic extension for a guide roller with a dovetail guide; Fig. 17 shows a front view of a section of the welding machine with the guide roller in an extended position; Fig. 18 shows a front view of a section of the welding machine with the guide roller in a retracted position; Fig. 19 shows a perspective view of a second fixed guide roller with an adjustment device for track alignment; Fig. 20 shows a flowchart of a method for thermally joining material webs.

[0032] Fig. 1 und Fig. 2 Figure 1 shows a perspective schematic representation of an exemplary welding machine 1 for the thermal joining of material webs. The welding machine 1 is designed for edge-to-edge joining of an overlapping upper material web to a lower material web, which can be bonded together by applying heat and subsequent pressure. The welding machine 1 has a heating device 10 and a chassis 20 with a guide rod 30 for guiding the welding machine.

[0033] The heating device 10 is designed for at least partially heating the material webs to be joined in a joining area. The heating device 10 is designed as a hot air blower with a blower body 11 with an internal heating element and a fan for generating an air volume flow, and a hot air nozzle 12. Fig. 1 The heating unit 10 is in a working position. Fig. 2 In contrast, the heating device is in a rest position, preferably extended laterally and tilted upwards. In the working position, the hot air nozzle is inserted in an overlap area between an upper and a lower material web (not shown). This allows the heating device to heat the underside of the upper material web and the top side of the lower material web, and in particular to at least partially plasticize or melt them. Alternatively, the heating device 10 can be designed as a heating wedge device with an electrically heated heating wedge.

[0034] Especially in roof sealing, the material sheets, such as sealing membranes, are welded in their overlap area using so-called ground-level hot air welding machines. A hot air nozzle attached to a hot air blower slides between the overlapping material sheets. This nozzle, or the entire hot air blower, is supposed to be extended into and out of the overlap at the beginning and end of the welding process. A so-called retraction device can be responsible for this, which moves the hot air blower in a controlled manner between a rest position ( Fig. 2 ) and a work position ( Fig. 1 ) moved back and forth. The hot air blower is typically moved laterally (axially) along a transverse axis and simultaneously rotated around an axis.

[0035] One working direction of the welding machine 1 is in Fig. 1 The direction of travel is indicated by an arrow and designated by reference numeral 32. The working direction here refers to a feed direction in which the welding machine 1 is guided during operation for edge-to-edge joining along the overlapping material webs. The chassis 20 has a pressure roller 21, which is configured to apply pressure to the material webs behind the heating unit 10 in the working direction. The pressure roller 21 can also simultaneously be configured as a drive roller, which automatically drives the welding machine 1. In the illustrated embodiment, however, an optional separate drive roller 22 is provided. In the illustrated embodiment, the chassis also has a first guide roller 23 and a second guide roller 24. The guide rollers are arranged at the front in the working direction 32. The first guide roller 23 can therefore be referred to as the left guide roller, and the second guide roller 24 can be referred to as the right guide roller.

[0036] To further improve airflow and heat transfer between the overlapping material webs, a pressure belt 23 can optionally be provided. The pressure belt 23 extends from between the pressure roller 21 to a preferably tensionable belt guide pulley 24, which is arranged next to or in front of the hot air nozzle in the working direction, to press the edge of an overlapping upper material web (not shown) against an overlapping lower material web (also not shown). The pressure belt 23 can be configured to press the overlapping edge of the upper material web against the lower material web, thus preventing the hot air flow from the hot air nozzle 12 from penetrating under the overlapping upper material web. The lateral sealing of the overlapping edge reduces power loss and allows the hot air flow to be directed against the direction of travel of the welding machine 1.

[0037] As in the Fig. 1 und Fig. 2 As shown in the illustrated embodiment, the welding machine 1 can further comprise a controller 27 (also referred to as the control unit) and a display unit 28. In the present embodiment, the controller 27 and the display unit 28 are arranged on the top side of the welding machine. It is understood that the controller 27 and / or display unit 28 can also be designed as wireless units connected to the welding machine via a communication interface. For example, a smartphone or tablet can be used with appropriate software as the display unit 28 or as the user interface for a controller.

[0038] The welding machine 1 can also have a receptacle 40 for one or more additional weights 50, which are designed to increase pressure on the pressure roller 21. Fig. 1 Figure 1 shows a perspective view of the welding machine 1 with an additional weight 50. Furthermore, the welding machine 1 can also have a permanently installed weight 51, which defines a minimum contact pressure without additional weights.

[0039] As in Fig. 1 bis Fig. 3 As shown, the chassis 20 is formed by a support frame 61 with a housing 62, as well as by the pressure roller 21 and the two guide wheels 23, 24. The chassis has a longitudinal axis parallel to the working direction 32 and a transverse axis perpendicular to it, which defines a chassis plane. The heating unit 10 is movably mounted relative to the support frame 61 with the housing 62 by means of a telescopic extension 70. Furthermore, at least one of the two guide wheels 23, 24 can be movably mounted relative to the support frame 61 with the housing 62 by means of a further telescopic extension 80. In other words, the heating unit 61 and / or the guide wheel 24 can be extended transversely to the drive direction 32 by means of a telescopic extension.

[0040] In the section relating to Fig. 1 bis Fig. 10 In the described embodiment, the heating device 10 is arranged on the support frame 61 with the housing 62 so as to be movable in the transverse direction by means of the telescopic extension 70.

[0041] The odd numbers show Fig. 1 , Fig. 3, Fig. 5, Fig. 7 as well as Fig. 9 und Fig. 10 The welding machine or parts thereof, with the telescopic extension in a retracted state in a working position. The straight Fig. 2 , Fig. 4, Fig. 6 und Fig. 8 In contrast, they show the welding machine or parts thereof with the telescopic extension in an extended state in a rest position. Fig. 3 and Fig. 4 show a front view of the welding machine 1 in a working position with the telescopic extension 70 for the heating unit 10 retracted ( Fig. 3 ) compared to a front view of the welding machine 1 in a rest position with extended telescopic extension 70 for the heating device 10 ( Fig. 4 ). The Fig. 5 and Fig. 6 show a perspective schematic representation of a telescopic extension for a heating device for a welding machine in a retracted state ( Fig. 5 ) or in an extended state ( Fig. 6 ). Accordingly, they show Fig. 7 a side view of the 70mm telescopic extension Fig. 5 . in a state retracted into housing 62 and Fig. 8 a side view of the telescopic extension Fig. 5 . in a state extended from housing 62.

[0042] The telescopic extension 70 has an axis 71, with the heating element 10 being fixedly attached to the axis 71 of the telescopic extension 70. In the illustrated embodiment, a connecting plate 72 is arranged on the axis 71. The heating element 10 can be fixedly but releasably attached to the connecting plate 72, for example, by means of a screw connection. The housing 62 can have a bearing housing 63 fixedly arranged on or in the housing. The bearing housing 63 is simultaneously part of the telescopic extension and, together with the further housing 62, serves to receive the telescopic extension in the retracted state, as, for example, in Fig. 3 und Fig. 7 shown.

[0043] The axis 71 can be slidably and rotatably mounted in the fixed bearing housing 63. To control the heating device 10 between the rest position ( Fig. 2 , Fig. 4 ) and the work position ( Fig. 1 , Fig. 3 To move the heating device 10 back and forth, it is axially displaced along the axis 71 and simultaneously rotated about the axis. In the rest position ( Fig. 2 , Fig. 4 The axis 71 of the telescopic extension 70 can be locked both axially and rotationally. In the illustrated embodiment, a radial, spring-loaded locking bolt 73 is provided for this purpose, attached to the bearing housing 63, which can engage in a bore 74, 74' provided in the axis 71. In a further development, the locking is released by an axially inserted, preferably spring-loaded, long bolt 75, which pushes the locking bolt 73 out of the bore 74, 74', as exemplified in Fig. 9 und Fig. 10 The long bolt 75 is also referred to as a coaxial bolt, since it is arranged coaxially in the axis 71.

[0044] In the resting position (see Fig. 2 , Fig. 4 As a first axial and rotational position relative to the support frame, the heating device can be fixed both axially and rotationally by means of the proposed telescopic extension. Here, as in Fig. 5 A bore 74 is shown in the axis 71, the size of which is adapted in a longitudinal and transverse direction to the size of the locking bolt 73. This fixes the axis both axially and rotationally. In contrast, in the working position (see Fig. 1 , Fig. 3 It is desirable if the heating device 10 is axially locked by means of the telescopic extension, but allows rotational movement over a certain angular range. As, for example, in Fig. 8 As shown, the bore 74' can therefore be designed as an elongated hole instead of a (round) bore. The release of the locking mechanism can be achieved with the same elongated bolt or coaxial bolt 75, but a different recess is used. As shown in Fig. 9 und Fig. 10 As shown, the locking bolt 73 is guided through the bore 74' into a recess of the coaxial bolt. When the coaxial bolt is axially aligned with the axis 71 towards the housing 62 (see e.g. Fig. 8 When the locking bolt 73 is pressed, it can be pushed radially outwards, for example, by a chamfered side wall of a recess in the coaxial bolt. The locking mechanism can thus be easily released.

[0045] As in Fig. 9 A handle 77 is shown at an outwardly facing end of the axis 71 with the coaxial bolt 75. The welding machine is designed so that the heating device 10 can be moved with the axis 71 of the telescopic extension 70 using the handle 77. The handle 77 also serves to release the locking mechanism, as it is connected to the coaxial bolt 75. The handle 77 with the coaxial bolt 75 can be supported on the axis 71 by a spring 76. When the handle 77 is not actuated, the spring 76 ensures that the coaxial bolt is positioned so that the locking pins engage in the recesses of the coaxial bolt 75, thus enabling secure locking.

[0046] The welding machine preferably has a drive unit for automatic movement. It would be desirable to ensure that the welding machine does not move automatically or is not accidentally activated when in its rest position. The drive unit can therefore be coupled to a start-up switch, which is configured to provide an enable signal for the drive unit. This can be a control signal. Alternatively, the start-up switch can be used to connect or disconnect the power supply to the drive unit. Fig. 7 and 8 Figure 1 shows an advantageous schematic arrangement of a starting switch 68, wherein the starting switch is arranged inside the housing 62. This protects the starting switch and reduces the risk of malfunction. In the rest position, as shown in Figure 2, the starting switch is located inside the housing 62. Fig. 4 und Fig. 8 As shown, the approach switch is open. In the working position, as shown in Figures 3 and 7, the approach switch is closed. In the illustrated embodiment, the approach switch is actuated by the retracted axis 71 of the telescopic extension 70. In the retracted state, the axis can, for example, actuate an electromechanical switch within the housing, which transmits a signal to the control unit that switches the drive (feed) of the welding machine on or off. Optionally, a delay can be provided to allow the operator to reposition their hand to the guide rod.

[0047] In the section relating to Fig. 11 bis Fig. 18 In the described embodiment, the caster 24 is movably arranged in the transverse direction on the support frame 61 with the housing 62 by means of the telescopic extension 80. Optionally, in addition to the first telescopic extension 70 for the heating device 10, a further or second telescopic extension 80 can also be provided for the caster 24. Figure 1 shows... Fig. 11, Fig. 12, Fig. 14 and Fig. 17 the telescopic extension 80 in an extended position. Fig. 13, Fig. 15 and Fig. 18 The figures show the telescopic extension 80 in a retracted state. An advantage of this embodiment is that, if necessary, for example for transport or in confined workspaces, the support with the caster can be completely retracted into the machine housing using the telescopic extension 80. In the extended state, however, high stability and good straight-line tracking characteristics can be provided.

[0048] The telescopic extension 80 has an axle 81, with the guide roller 24 arranged at a transversely outer end of the axle 81. The housing 62 can have a bearing housing 64 fixedly attached to or within the housing. The bearing housing 64 is simultaneously part of the telescopic extension and, together with the further housing 62, serves to receive the telescopic extension in the retracted state, as for example in Fig. 13 The other guide roller 23 is (in the transverse direction on the opposite side) rigidly connected to the chassis, in particular to a support frame 61 of the chassis. The rigidly connected guide roller 23 can further improve the stability and tracking of the welding machine, since no moving or sliding elements are required.

[0049] As in Fig. 16 As shown, the telescopic extension 80 for the caster 24 can have a dovetail guide. An advantage of designing the telescopic extension for the caster as a dovetail guide is that the telescopic extension can be mounted particularly smoothly even under a lateral load perpendicular to the extension direction, while simultaneously offering minimal play, which in turn improves stability and guiding accuracy.

[0050] As in Fig. 17 und Fig. 18 As shown, the telescopic extension 80 can optionally have an actuating lever 85 with which various positions 86, 86', 86" can be set in the longitudinal direction of the telescopic extension 80. For example, a metal plate can be mounted on the axis 81 which, depending on its lateral position, can engage in corresponding recesses on the housing 62. This allows predefined lateral positions (in this case three) to be set with repeatable precision.

[0051] Fig. 19 Figure 1 shows a perspective view of a second fixed guide roller 23 with an adjustment device 90 for track adjustment. The adjustment device 90 may have a display 91 which indicates the alignment of the guide roller 23. The alignment or track of the guide roller can be adjusted, for example, by means of one or more adjusting screws 92.

[0052] Fig. 20Figure 100 shows a flowchart of a method for thermally joining material webs, in particular for edge-to-edge joining of an overlapping upper material web to a lower material web, which can be bonded together by applying heat and subsequent pressure. In a first step S101, a welding machine, as described in the present disclosure, is provided. In a second step S102, the heating device 19 for at least partially heating the material webs to be joined in a joining area is moved from a rest position to a working position by means of the telescopic extension. In a third step S102, the material webs are thermally joined with the welding machine.

[0053] In summary, the solutions proposed herein enable the provision of an improved welding machine for the thermal joining of material webs, in particular for edge-to-edge joining of an overlapping upper material web to a lower material web, which can be bonded together by applying heat and subsequent pressure. The proposed solution allows for the provision of a welding machine that is easy to operate and / or reduces maintenance requirements. Furthermore, compared to fully automatic lowering and swiveling devices, it can reduce manufacturing complexity.

Claims

1. Automatic welding machine (1) for thermal joining of material sheets, in particular for edge-side joining of an overlapping upper material sheet to a lower material sheet, to be connected to one another in a materially bonded manner under the application of heat and subsequent application of pressure, comprising - a heating device (10) for at least partially heating the material sheets to be joined in a connection region, - a support frame (61) with a housing (62), - a pressure roller (21), - at least two travelling rollers (23, 24), wherein the pressure roller (21) and the traveling rollers (23, 24) are arranged on the support frame (61) and together with the support frame form a chassis (20), wherein the chassis (20) comprises a longitudinal axis and a transverse axis perpendicular thereto, which span a chassis plane, wherein the heating device (10) is arranged to be movable by a telescopic pull-out (70, 80) relative to the support frame (61) in directions parallel to the transverse axis, wherein the first travelling roller (24) and the heating device (10) are with respect to a longitudinal center of the chassis arranged on opposite sides of the chassis (20); wherein the telescopic pull-out (70, 80) comprises an axle (71, 81), wherein the heating device (10) is fixedly attached to the axle (71, 81) of the telescopic pull-out, wherein in an extended state the axle is pulled-out of the housing (62) of the support frame (61) and in a retracted state is received by the housing (62) of the support frame (61); wherein the elements of the telescopic pull-out are pushed into one another; and characterized in that the heating device (10) fixedly attached to the axle is configured as a hot air blower with a blower body (11) with an internal heating element and a fan for generating an air volume flow and a hot air nozzle.

2. Automatic welding machine according to claim 1, wherein the heating device (10) is arranged rotatably relative to the support frame (61) about an axis parallel to the transverse axis, wherein the heating device (10) is fixable axially and rotationally relative to the support frame (61) at least in a first axial and rotational pose and is fixable at least axially relative to the support frame (61) in a further, second axial and rotational pose which is at least axially different from the first pose.

3. Automatic welding machine according to claim 2, wherein the heating device (10) is arranged on the support frame (61) by the telescopic pull-out (70), wherein the telescopic pull-out comprises a receptacle (72) fixed to the support frame and a shaft (71), wherein the shaft extends between a first axial shaft end and a second axial shaft end along a shaft axis parallel to the transverse axis, wherein the second axial shaft end is the axial shaft end facing away from the housing (62), wherein the shaft is mounted at the receptacle so as to be movable along the shaft axis and rotatable about the shaft axis, and wherein the heating device (10) is arranged on the shaft in a region of the second axial shaft end.

4. Automatic welding machine according to claim 3, wherein for fixing the heating device (10) in the first pose and / or in the second pose the shaft can be releasably fixed to the receptacle by a locking device (73) of the receptacle (72).

5. Automatic welding machine according to claim 4, wherein the locking device comprises at least one locking bolt (73), wherein the locking bolt is oriented in a direction of a locking axis perpendicularly intersecting the shaft axis and is movable in the direction of the locking axis, and wherein the shaft (71) can be fixed at least in the first pose and / or in the second pose by an at least partial engagement of the locking bolt (73) radially to the shaft axis into the shaft; in particular wherein the locking bolt is loaded by a spring force (76) in direction of the shaft axis.

6. Automatic welding machine according to one or more of claims 2 to 5, wherein a handle lever (77) is arranged at the second axial shaft end, which is configured to provide a manual rotation of the shaft (71) about the shaft axis, a manual displacement of the shaft in directions along the shaft axis and / or a manual release of a fixation of the shaft (71) from the receptacle (72).

7. Automatic welding machine according to claim 6, wherein a coaxial stud (75) is received in an interior of the shaft (71) of the telescopic pull-out (70), wherein the coaxial stud (75) extends parallel to the shaft axis at least partially through the shaft (71), wherein the coaxial stud (75) is movable in directions to the shaft axis, wherein the locking bolt (73) can be at least partially brought into engagement with the coaxial stud (75) at least in the first pose and / or the second pose, and wherein the locking bolt (73) can be disengaged from the coaxial stud by a movement of the coaxial stud (75) in a direction along the shaft axis relative to the shaft (71).

8. Automatic welding machine according to claim 7, wherein the coaxial stud (75) projects with an axial end beyond the second end of the shaft out of the shaft (71), wherein the handle lever (77) is arranged at this axial end of the coaxial stud (75), wherein a spring element (76) is clamped between the handle lever (77) and the second shaft end, wherein a movement of the coaxial stud along the shaft axis in the direction of the second shaft end is limited by a stop inside the shaft (71) in combination with a counterstop of the coaxial stud (75).

9. Automatic welding machine according to any of the preceding claims, wherein the automatic welding machine (1) comprises a drive (22), wherein the drive is coupled with a start-up switch (68) which is configured to provide a release signal for the drive, wherein the start-up switch (68) is arranged in the interior of the housing (62) and is configured to be actuated by retraction of the telescopic pull-out (70) into the interior of the housing (62), in particular by a retracting shaft (71) of the telescopic pull-out (70).

10. Automatic welding machine according to any of the preceding claims, wherein the first traveling roller (24) is arranged on the support frame (61) by the telescopic pull-out (80), wherein the telescopic pull-out for the traveling roller (24) comprises a dovetail rail.

11. Automatic welding machine according to claim 10, wherein the telescopic pull-out (80) with the first traveling roller (24) is configured not to protrude beyond the support frame at least at a minimum distance of the traveling roller (24) from the longitudinal center of the support frame (61) parallel to the transverse axis in a direction parallel to the transverse axis.

12. Automatic welding machine according to claim 11, wherein the telescopic pull-out (80) with the first traveling roller (24) terminates flush with the support frame (61) with an axial cantilever end facing away from the longitudinal center.

13. Automatic welding machine according to any of the preceding claims, further comprising an adjusting device (90) for adjusting the alignment of at least one of the traveling rollers (23).

14. Method (100) for thermal joining of material sheets, in particular for edge-side joining of an overlapping upper material sheet to a lower material sheet, to be joined together in a materially bonded manner under the application of heat and subsequent application of pressure, comprising the steps of - providing an automatic welding machine (1) according to any of the preceding claims (S101); - transferring the heating device (10) for at least partially heating the material sheets to be joined in a connection region from a rest position to a working position using the telescopic pull-out (70) (S102); and - thermal joining of the material sheets with the automatic welding machine (1) (S102).