Strapping machine and method

Abstract

The invention relates to a device for strapping an object by means of a band, comprising - a device for forming a band loop around the object, - a guide device which has a guide body (9) with at least one guide surface (24, 25) against which a portion of the band loop can be placed, and - an ultrasound connection device which is configured to connect the portion with another portion of the band loop. The problem addressed by the invention is that of modifying a strapping machine such that it is suitable for the use of band made of paper material as the strapping means. For this purpose, the guide body (9) has at least one fluid channel (26), which is connected to an inlet opening and at least one outlet opening (29, 30) of which opens out on at least one of the guide surfaces (24, 25) of the guide body (9), wherein the guide body (9) is coupled to a drive means (22) which is configured to move the guide body (9) from a first position between the two portions (18, 19) of the band loop into a second position outside the zone between the portions (18, 19) of the band loop.

Description

Strapping machine and process Technical area

[0001] The invention relates to a device for strapping an object by means of a band according to the preamble of claim 1. The invention further relates to a method for strapping an object by means of a band according to the preamble of claim 8.

[0002] Strapping machines that form a strap loop around an object to be strapped, tension it, and weld the end sections of the strap loop together are known from the prior art. The applicant's document DE 10 2009 001 544 A1 shows such a strapping machine, which features a stationary strap guide frame with which the strap loop is formed. A strap channel is arranged in the strap guide frame. The strap is inserted into the strap channel by a belt drive. The free strap end is clamped at the end of the insertion process, and the strap exits the strap channel, is retracted, and tensioned. The two end sections of the strap loop are then pressed against each other and welded together using a sonotrode. The sonotrode for welding the strap ends is known from DE 103 23 783 A1, the applicant's document.Alternative devices that allow the strap loop to exit the stationary strap channel are known from EP 2 051 909 B1 and EP 3 891 075 B1. It is also known that the strap guide frame is not stationary, but can be moved from a rest position below a support surface to a closed position above the support surface and back again. Such a strapping machine is known from EP 1 243 509 B1 by the applicant. Strapping machines are also known in which the strap loop is manually pulled around the object to be strapped (cf. EP 1 357 371 B1). The device described here relates to a strapping machine with any desired devices for forming the strap loop.

[0003] Common strapping machines use plastic straps, typically made of polypropylene or polyester. Both materials are well suited for welding using an ultrasonic joining device, as described in DE 103 23 783 A1.

[0004] More recently, methods and devices for joining paper materials using an ultrasonic friction welding device have also been described. A device for joining paper materials using an ultrasonic friction welding device is described in EP 3 749 514 B1.

[0005] DE 10 2020 131 191 A1 describes a packaging device for applying an outer packaging material made of paper or cardboard using an ultrasonic joining device to form a joint between two overlapping layers. It is proposed here to moisten the outer packaging material with water or steam, at least in the overlapping area, to promote the joining process. JP H08-300 623 A discloses a moistening roller for printing paper. Further packaging methods are known from DE 10 2022 111 528 A1 and DE 42 25 480 A1. DE 10 2013 225 743 A1 describes an ultrasonic joining method.

[0006] The object of the invention is to adapt a strapping machine so that it is suitable for using paper strapping material. Furthermore, it is an object to develop an operating method for such a strapping machine.

[0007] This object is achieved according to the invention by the features of claims 1 and 7. Practical embodiments emerge from the subclaims.

[0008] The device described here for strapping an object using a band comprises the following: a device for forming a band loop around the object, a guide device which has a guide body with at least one guide surface against which a section of the band loop can be placed, and an ultrasonic connecting device which is configured to connect the section to another section of the band loop, wherein the guide body is coupled to a drive means which is configured to move the guide body from a first position between the sections of the band loop to a second position outside the zone between the sections of the band loop.

[0009] For use with strapping bands made of fibrous material, in particular paper, the guide body has at least one fluid channel which is connected to an inlet opening and which opens with at least one outlet opening on the guide surface of the guide body.

[0010] A fluid can be fed to the fluid channel in the guide body via the inlet opening, which fluid exits through the outlet opening on the guide surface against which the section of the tape loop to be connected rests, at least temporarily, during the formation of the tape loop. This allows targeted moistening to be achieved, which causes the fiber material of the tape to swell and enables a connection using ultrasound. In particular, water can be supplied as a fluid, which wets the guide surface and moistens the section of the tape loop that is adjacent to it. An additive can be added to the water to increase the adhesion of the moistened section of the tape loop to the section to be connected. However, an alcohol can also be used to moisten the tape. Alternatively, a gel or dispersion can be added.For example, water-based or alcohol-based gels can provide highly targeted surface moistening of the belt material without completely soaking the entire belt loop. Finally, it is also possible to use a gaseous fluid such as steam or wet steam to moisten the section of the belt loop that rests against the guide surface.

[0011] If the guide body has multiple fluid channels, different fluids can also be supplied to the surface of the belt through the different fluid channels. For example, two flowable components can be supplied, with one component causing the curing or setting of the second component. A fast-curing two-component fluid system can prevent softening of the moistened belt and ensure a high-strength connection between the welded belt sections.

[0012] Targeted moistening prior to joining using ultrasound can also be achieved in other ways. For example, the strip ends to be joined can be spatially separated from one another and sprayed with a small amount of water. Alternatively, a sponge moistened with water can be pressed against one or both strip ends so that the sponge moistens the strip ends. Any other method of moistening the strip ends prior to joining using ultrasound is suitable for carrying out the joining method according to the invention. Moistening using the guide surface for the strip end with an outlet opening has the advantage of allowing the process steps to be carried out with high speed and precision.

[0013] In one embodiment, the guide body can have two opposing guide surfaces, with a first section of the belt loop resting against the first guide surface and a second section of the belt loop resting against the second guide surface. A tensioning device is provided for tensioning the formed belt loop. The drive means moves the guide body out of the zone between the sections of the belt loop, so that the ultrasonic connecting device subsequently presses the sections of the belt loop against each other and connects them.

[0014] In other words, the strapping band is moved along two sides of the guide body during the strapping process. When the free end of the band has reached its final position, the free end section of the formed band loop is secured, usually clamped, and the band loop is tensioned. A section of the band near the free end rests against a guide surface of the guide body. This section can be moistened with water by supplying water through the inlet opening and the fluid channel to the outlet opening. After the band loop has been tensioned, the second section of the band to be joined rests against the guide body on the opposite guide surface.If it is necessary to moisten both contacting belt surfaces in order to achieve an optimal connection between the belt sections, a second inlet opening can also be provided, which is connected via a second fluid channel to an outlet opening on the opposite guide surface. After the belt loop has been tensioned, water can also be fed to the second belt section through the second inlet opening. Alternatively, one fluid channel can transport water to outlet openings on both guide surfaces of the guide body. Different fluid channels can lead to the opposite guide surfaces of the guide body, and a flowable component of a two-component system can be fed to each of the two opposite guide surfaces of the guide body, so that each of the two surfaces of the belt to be joined is wetted with a component of a two-component system.The two components only come into contact with each other when the guide body is removed between the two surfaces of the belt to be joined.

[0015] Because the moistening device is arranged in the guide body of the tensioning and connecting unit of the strapping device, it is possible to carry out the moistening using ultrasound shortly before the connecting process. In this way, it can be avoided that the moistened strap section becomes excessively soaked before it is subjected to ultrasound. It can be provided that before the strap sections to be welded are pressed together and before an ultrasonic vibration is applied by means of the ultrasonic connecting device, a first time interval elapses, which has a predetermined duration during which the moistened strap section swells. It can also be provided that after the two pressed strap sections have been connected by ultrasound, the strap ends are clamped for a second period of time in order to allow the connection to solidify through further drying.

[0016] As mentioned, the guide body can have multiple fluid channels connected to one or more inlet openings. It can also have multiple outlet openings. Both guide surfaces of the guide body can have outlet openings. In particular, the inlet openings, fluid channels, and outlet openings can be arranged such that water can be selectively supplied to the guide surfaces of the guide body. This makes it possible to start the water supply to the respective guide surface only when the strip section to be welded is in contact with the respective guide surface.

[0017] In practice, water or another fluid at elevated pressure can be fed into the fluid channel via the inlet opening. For example, the inlet opening can be connected to a pump that delivers a predetermined amount of water to the guide body. Alternatively, it is also possible to connect the inlet opening via a shut-off valve to a water supply line that is pressurized and connected to the water supply network. By controlling the shut-off valve, the duration during which water is supplied to the inlet opening can be determined.

[0018] Furthermore, excess water or other fluid can be sucked away via the fluid channels. For this purpose, the pump can be switched to suction mode, for example. Alternatively, a multi-way valve can be used to connect the inlet opening to a suction line, where negative pressure prevails and through which excess water can be sucked away. Precise adjustment of the duration and, if necessary, the amount of water supplied makes it possible to achieve a predetermined degree of moistening. This allows the optimal degree of moistening to bond the surfaces of the two belt sections together using ultrasound.

[0019] In practice, the ultrasonic joining device can comprise a sonotrode and a counterplate between which the two strip sections are clamped, wherein the surface of the sonotrode can be pressed towards the counterplate with a clamping force acting perpendicular to the surface, and wherein the sonotrode is configured to oscillate in a direction parallel to the clamping force. Such an ultrasonic joining device has already been used for welding plastic strips. As is clear from EP 3 749 514 B1, a sonotrode that oscillates essentially parallel to the surfaces to be joined and thus perpendicular to the clamping force is preferred for joining paper using ultrasound. Welding using a sonotrode oscillating in the direction of the clamping force requires very targeted moistening of the strip sections to be welded.

[0020] The method for strapping an object using a band, which is preferably made of paper, comprises the following steps: forming a band loop surrounding the object, wherein preferably in a guide device a first portion of the band loop bears against a first guide surface of a guide body and a second portion of the band loop bears against a second guide surface which is opposite the first guide surface, securing the free end of the band loop, tensioning the formed band loop around the object and separating the band loop from the band supply, pulling the guide body out of the zone between the end portions of the band loop, pressing the two end portions of the band loop against each other and connecting them by introducing ultrasound.

[0021] In order to enable an ultrasonic connection of band sections made of paper or similar fiber material, a fluid is supplied to at least one inlet opening of the guide body, which fluid is guided through a fluid channel to an outlet opening on at least one of the guide surfaces of the guide body against which a section of the band loop rests.

[0022] As explained above, in practice, water, water with additives, an alcohol, a gel, a dispersion or steam can be directed to outlet openings on both guide surfaces of the guide body, against each of which a section of the belt loop rests.

[0023] Furthermore, a predetermined amount of fluid can be supplied to the ends of the tape to be joined by means of a pump. Alternatively, the amount and / or duration of the fluid supply can be controlled by a shut-off valve.

[0024] Additionally, the pump can be switched to suction mode to drain excess water. Alternatively, a suction line can be provided that connects to the inlet opening to drain excess water.

[0025] Also as described above, the sonotrode can be made to oscillate in a direction parallel to the clamping force.

[0026] After water is supplied through the outlet opening of the guide surface to moisten the surface of the belt section resting against the guide surface, and before the opposing belt sections are joined by the ultrasonic bonding device, a first predetermined time interval can elapse during which the moistened belt swells. Tests have shown that the best bonding results are achieved by swelling the surface of the belt to be welded, made of paper or similar fiber material, for a period of several seconds. However, the swelling must not last too long to avoid completely moistening the fiber material, which could lead to softening and structural weakening.

[0027] Furthermore, it can be provided that after the mutually abutting band sections have been connected by the ultrasonic connecting device, a second predetermined time interval elapses in which the connection solidifies before a holding device for the ends of the band loop is released.

[0028] Furthermore, a heating device can be provided which heats the area surrounding the strip sections to be joined. For example, the heating device can heat the guide body. For this purpose, electrical heating elements can be built into the guide body, which can be heated by applying current. However, a hot air blower can also be provided, which blows hot air specifically into the area surrounding the strip sections to be joined. Finally, the sonotrode and the counterplate of the ultrasonic joining device can be heated in order to heat the strip ends during welding. Heating the strip sections to be joined causes the moistened strip sections to dry quickly, whereby the maximum strength of the joint between the two strip sections to be joined is quickly achieved.

[0029] Further practical embodiments and advantages of the invention are described below in conjunction with the drawings.

[0030] shows a perspective view of a strapping machine from above.

[0031] shows a side view of the strapping machine.

[0032] shows a cut-out side view of parts of the strapping machine.

[0033] shows an isolated perspective view of the strapping machine unit from Figures 3.

[0034] shows an enlarged side view of the area near the sonotrode of the unit.

[0035] shows an enlarged and sectioned side view of the area of ​​the aggregate near the sonotrode.

[0036] shows a corresponding view with the guide body retracted.

[0037] shows a perspective view of the area of ​​the aggregate above the sonotrode.

[0038] shows a corresponding view with the guide body retracted.

[0039] shows an enlarged sectional side view of the guide body with counter plate and lower guide plate.

[0040] shows a schematic side view of the contour of the slide with guide body to illustrate the course of the fluid channels

[0041] shows a corresponding representation in top view.

[0042] The strapping machine 1 shown in Figures 1 and 2 is used for strapping objects with a strapping band. It has a band guide frame 2 arranged above a support table 3. The object to be strapped is placed on the support table 3. The strapping band is guided around the object to be strapped within the band guide frame 2. The formed band loop is then tensioned until it fits snugly against the object to be strapped.

[0043] Figure 3 shows components of the strapping machine 1 from Figures 1 and 2. The strap guide frame 2 and a so-called pre-spooler 4 can be seen, with which strapping is fed from a strap reel (not shown) into a strap magazine 5. Above the strap magazine 5, a unit 6 can be seen, which has drive rollers and tensioning rollers for the strapping, as well as an ultrasonic joining device. Details of the unit 6 are described in more detail below. As stated at the beginning, alternative devices for forming the strap loop are also known in practice, which are not shown in the drawings. Instead of the rigid strap guide frame from Figures 1 to 3, a movable strap guide frame can be provided, which can be moved below the surface of the support table after the strap loop has been formed. The strap can also be guided around the object manually or mechanically.The same unit 6 can be used to connect the end sections of the formed belt loop, which will now be described in detail.

[0044] This shows a three-dimensional representation of the unit 6. The components of the ultrasonic joining device are shown here in solid lines, whereas the remaining components of the unit 6 are shown in dashed lines. A drive roller 7 can be seen, which pulls strapping tape from the tape magazine and conveys it through a feed channel 8 past a guide body 9 to the tape guide frame. After passing through the tape guide frame, the free tape end enters a receiving channel 10, which runs between the second, upper side of the guide body 9 and a counterplate 11 arranged above it. Furthermore, a first tensioning roller 12 and a second tensioning roller 13 can be seen, which can be pressed against each other. When the drive roller 7 conveys the tape into the tape guide frame, a large gap is set between the two tensioning rollers 12, 13 so that the tape can be pulled off the tape roll unhindered.After the drive roller 7 has pulled the strap out of the strap guide frame so that it fits tightly against the object to be strapped, the tension rollers 12, 13 are pressed against each other, tightening the strap loop around the object to be strapped. In this tensioned state, the end sections of the formed strap loop are clamped and connected to each other by a sonotrode 14. Clamping elements 15, 16 can be seen on both sides of the sonotrode 14, with which the end sections of the strap loop can be clamped.

[0045] The area of ​​the unit 6 above the sonotrode 14 is shown enlarged. It can be seen that a lower guide plate 17 is arranged between the guide body 9 and the sonotrode, which forms the second, lower wall of the feed channel 8.

[0046] Figure 6 shows the area of ​​the unit from Figure 5 in an enlarged and sectional view. The free end section 18 of the formed strap loop can be seen, which lies in the receiving channel 10. A signal generator (not shown) can be arranged on the counterplate 11, which signals to the control system of the strapping machine when the end section 18 has emerged from the end of the receiving channel 10. The signal from the signal generator causes the clamping element 16 to clamp the free strap end 18. The strap loop can now be retracted until it fits snugly around the object to be strapped and tensioned by means of the tensioning rollers 12, 13 (). The clamping element 15 is then moved upward and clamps the second end section 19 of the formed strap loop in the feed channel 8. This second end section 19 can now be cut off from the strap supply in the strap magazine and connected to the free end section 18.

[0047] As explained further below, the guide body 9 and a lower guide plate 17 are now moved out of the area between the sonotrode 14 and the counterplate 11. The sonotrode 14 can then be moved vertically upward from the position in Figure 6 until it presses the two end sections 18, 19 of the strapping band against each other and against the counterplate 11 with a predetermined clamping force. The sonotrode 14 is then excited by a vibration generator to produce ultrasonic vibrations, which connect the end sections 18, 19 of the strapping band. The vibration generator 20 can be seen in . The state in which the sonotrode 14 presses the two end sections 18, 19 of the strapping band against each other and against the counterplate 11 is shown in .Here it can also be seen that the two clamping elements 15, 16 fix the end sections 18, 19 in their position during the connecting process by means of the sonotrode 14, so that the tensile stress of the band loop does not act on the end sections 18, 19.

[0048] Figures 8 and 9 show a diagrammatic front view of the unit 6 from above with the counterplate 11 removed. It can be seen that the guide body 9 and the lower guide plate 17 are attached to the front end of a carriage 21. The carriage 21 is fastened to the unit 6 so as to be displaceable transversely to the plane of the formed belt loop. A drive pin 22 extends through the carriage 21 below a guide pin 23. The drive pin 22 forms the drive means for the carriage 21, which moves the carriage 21 into the front position shown in FIG. 1 and into the rear position shown in FIG. 1. In the front position, the guide body 9 is located between two sections of the belt loop. The free end section 18 of the belt loop rests on the upper guide surface 24 of the guide body 9. The section 19 of the belt loop connected to the belt roll rests against the lower surface of the guide body.After retracting and tensioning the strapping band, the second end section 19 of the formed band loop rests with its upper side against the lower guide surface 25 of the guide body 9, as shown in an enlarged manner.

[0049] As mentioned above, a band made of fiber material, in particular paper, is preferably used for strapping, which must first be moistened before being connected using an ultrasonic sonotrode. For this purpose, the guide body 9 has fluid channels 26 which extend between the upper guide surface 24 and the lower guide surface 25 and are shown enlarged. In the embodiment shown, three fluid channels 26 open onto both guide surfaces 24 and 25 on the top and bottom of the guide body 9. The two guide surfaces 24 and 25 lie against the mutually facing sides of the two end sections 18, 19. The water escaping through the mouths or outlet openings of the fluid channels 26 consequently wets the two mutually facing sides of the two end sections 18, 19 of the formed band loop.In an alternative embodiment not shown, the fluid channels can also be designed such that they open only on one side of the guide body and moisten the adjacent side of one of the two end sections 18 or 19 of the belt loop.

[0050] Figures 11 and 12 schematically show the course of the fluid channels in the carriage 21. Approximately in the middle of the carriage 21 there is an inlet opening 27 which can be connected to a fluid line through which water can be supplied or sucked out. The inlet opening 27 is followed by a fluid channel 28 which runs in the longitudinal direction of the carriage 11 and which, in the region of the guide body 9, divides into three fluid channels 26 which, at their upper ends, have upper outlet openings 29 which open out on the upper side of the guide body 9, and which, at their lower ends, have lower and lower outlet openings 30 which open out on the lower side of the guide body 9.

[0051] A predetermined amount of water can be supplied to the surfaces of the strapping band via the fluid channels 26, 28. If necessary, excess water can be suctioned off through the same fluid channels 26, 28.

[0052] After moistening, the guide body 9 is retracted until it reaches the position shown. The end section 19 of the strap loop, connected to the strap supply, can now be clamped using the clamping body 16. The two moistened end sections 18, 19 of the strapping band are then pressed against the counterplate 11 by the sonotrode 14 and joined together by ultrasonic vibrations. Unlike ultrasonic welding of plastic straps, the materials of the strap sections are not melted but merely matted together, creating a firm connection between the two end sections 18, 19.

[0053] If the moistened surface needs to swell for a certain amount of time to achieve a reliable connection, a first predetermined time interval can elapse after the supply of moistening the surface of the band section 18 and / or 19 and before the pressing together to connect the abutting band sections 18, 19 by the sonotrode, during which the moistened band swells. The time interval can be selected depending on the material of the band sections. Likewise, after the sonotrode and the counterplate have connected the abutting band sections 18, 19, a second predetermined time interval can elapse during which the connection solidifies and dries before the clamping elements 15, 16, which form a holding device for the end sections of the band loop, are released.The clamping elements 15, 16 are located between the moistened end sections and the central region of the belt loop and absorb the tensile force present in the tensioned belt loop. The clamping elements 15, 16 can clamp the end sections 18, 19 of the belt loop until the connection between the end sections 18, 19 is tight enough to absorb the tensile force of the belt loop.

[0054] As mentioned above, electrical heating elements can be integrated into the guide body 9 and / or the sonotrode 14 and / or the counterplate 11. These heating elements heat these components through the supply of electricity and ensure that the moistened sections of the tape loop dry quickly again. Alternatively or additionally, heating fans (not shown) can be provided, which blow hot air into the area where the end sections 18, 19 of the tape loop are joined together. This heating causes the joined end sections 18 and 19 to dry quickly, thus ensuring maximum strength for the connection.

[0055] If creating an optimal bond between the adjacent end sections 18, 19 of the tape loop requires not only water but also flowable additives such as glue, these additives can also be conveyed through the fluid channels to the surfaces to be joined. In this case, it is recommended to occasionally flush the fluid channels.

[0056] It should be noted that the designations top, bottom, front, back, right, and left apply to the assembly 6 shown in the drawings. However, there are also assemblies that create a connection in a vertically running section of a belt loop. In this case, all components of the assembly are rotated by 90°. In principle, the assembly 6 can have any orientation in space.

[0057] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention is not limited to the described embodiments. It may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

[0058] 1 Strapping machine 2 Strap guide frame 3 Support table 4 Pre-spooler 5 Strap magazine 6 Unit 7 Drive roller 8 Feed channel 9 Guide body 10 Take-up channel 11 Counter plate 12 First tension roller 13 Second tension roller 14 Sonotrode 15 Clamping element 16 Clamping element 17 Lower guide plate 18 End section 19 End section 20 Vibration generator 21 Carriage 22 Drive pin, drive means 23 Guide pin 24 Upper guide surface 25 Lower guide surface 26 Fluid channel 27 Inlet opening 28 Fluid channel 29 Upper outlet opening 30 Lower outlet opening

Claims

A device for strapping an object by means of a band, comprising: a device for forming a band loop around the object, a guide device which has a guide body (9) with at least one guide surface (24, 25) against which a section (18) of the band loop can be placed, and an ultrasonic connecting device which is designed to connect the section (18) to another section (19) of the band loop, characterized in that the guide body (9) has at least one fluid channel (26, 28) which is connected to an inlet opening (27) and which opens into at least one outlet opening (29, 30) on at least one of the guide surfaces (24, 25) of the guide body (9), wherein the guide body (9) is coupled to a drive means (22) which is designed to move the guide body (9) from a first position between the sections (18,19) of the belt loop into a second position outside the zone between the sections (18, 19) of the belt loop., Device according to claim 1, characterized in that the guide body (9) has two mutually opposite guide surfaces (24, 25), wherein a first section (18) of the band loop can be placed on the first guide surface (24) and a second section (19) of the band loop can be placed on the second guide surface (25), wherein the ultrasonic connecting device presses the two sections (18, 19) of the band loop against each other and connects them to each other. Device according to claim 1 or 2, characterized in that the guide body (9) has at least one of the following features: a plurality of fluid channels (26, 28) connected to one or more inlet openings (27); a plurality of outlet openings (29, 30); both guide surfaces (24, 25) have at least one outlet opening (29, 30). Device according to one of the preceding claims, characterized in that the inlet opening (27) can be connected to a pressure line and / or a suction line. Device according to one of the preceding claims, characterized in that the ultrasonic connecting device has a sonotrode (14) and a counter-plate (11), between which the two sections (18, 19) of the strapping band can be clamped, wherein the surface of the sonotrode (14) can be pressed towards the counter-plate (11) with a clamping force acting perpendicular to the surface and wherein the sonotrode (14) is designed to oscillate in a direction parallel to the clamping force. Device according to one of the preceding claims, characterized in that it comprises a heating device for heating the surroundings of the band sections (18, 19) to be joined together. Device according to claim 6, characterized in that the heating device heats the guide body (9) and / or the sonotrode (14) and / or the counterplate (11). A method for strapping an object using a paper band, comprising the following steps: forming a band loop surrounding the object, securing the free end of the band loop, tensioning the formed band loop around the object, separating the band loop from the band supply, and pressing one section (18) against each other and connecting it to a second section (19) of the band loop by introducing ultrasound, characterized in that, before the connection, at least one of the two sections (18, 19) is moistened by a guide body (9) arranged between the sections (18, 19) of the band loop, wherein the guide body (9) is moved by a drive means (22) from a first position between the sections (18, 19) of the band loop to a second position outside the zone between the sections (18, 19) of the band loop. Method according to claim 8, characterized in that at least one of the sections (18, 19) of the belt loop is placed against a guide surface (24, 25) of a guide body (9) and that, for moistening, a fluid is passed through a fluid channel (26, 28) to an outlet opening (29, 30) on the guide surface (24, 25) of the guide body (9). Method according to claim 8 or 9, characterized by at least one of the following features: before welding the sections (18, 19) of the band loop, the guide body (9) is pulled out of the zone between the sections (18, 19) of the band loop; two sections (18, 19) of the band loop rest against two opposing guide surfaces (24, 25) of the guide body (9), and a fluid is directed to outlet openings on both guide surfaces (24, 25) of the guide body (9); a predetermined amount of fluid is supplied to the sections (18, 19) of the band to be joined together; excess fluid is sucked off. Method according to one of claims 8 to 10, characterized in that the ultrasonic connecting device has a sonotrode (14) and a counter-plate (11) between which the two band sections (18, 19) are clamped, wherein the surface of the sonotrode (14) is pressed towards the counter-plate (11) with a clamping force acting perpendicular to the surface and wherein the sonotrode (14) is caused to oscillate in a direction parallel to the clamping force. Method according to one of claims 8 to 11, characterized in that after the supply of fluid through the outlet opening of the guide surface (24, 25) for moistening the surface of the band section (18, 19) lying against the guide surface (24, 25) and before the joining of the opposing band sections (18, 19) by the ultrasonic joining device, a first predetermined time interval elapses in which the moistened band swells. Method according to one of claims 8 to 12, characterized in that after the joining of the opposing band sections (18, 19) by the ultrasonic joining device, a second predetermined time interval elapses in which the connection solidifies before a holding device for the ends of the band loop is released. Method according to one of claims 8 to 13, characterized in that the surroundings of the strip sections (18, 19) to be joined together are heated. Method according to claim 14, characterized in that the guide body (9) is heated.

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