Method for connecting a tube body to a closure element, and a sonotrode for this purpose
Patent Information
- Application Number
- EP2024710059
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-03-07
- Filing Date
- 2024-03-06
- Publication Date
- 2026-01-14
AI Technical Summary
The existing methods for connecting hose bodies to final elements, such as in catheter manufacturing, rely on adhesives, which incur additional costs, pollute the environment, and require lengthy cycle times due to hardening processes, posing challenges in hygienic environments like the medical sector.
A sonotrode with a guide section and a processing section is used to transmit ultrasonic vibrations to create a firm connection between the hose body and the closing element without adhesives, utilizing a sealing surface to melt the material and form a secure bond, while the guide section prevents melt from entering the hose body.
This method eliminates the need for adhesives, reduces environmental pollution, shortens cycle times, and ensures a reliable, high-quality connection, suitable for hygienic environments by using ultrasonic vibrations to melt and bond materials.
Smart Images
Figure EP2024055831_12092024_PF_FP_ABST
Abstract
Description
[0001] Herrmann Ultrasound Technology GmbH & Co. KG
[0002] Our reference: 230500WG
[0003] Method for connecting a hose body to a closure element and a sonotrode therefor
[0004] The present invention relates to a method for connecting a hose body which is open at least on one side to a closing element and to a sonotrode therefor.
[0005] In the manufacture of catheters, for example, a connecting element is connected to a tube. In this case, the tube body is designed as a tube open on both sides, and the connecting element forms the closing element. However, the tube body can also be closed on one side. Instead of the connecting element, a closing element can also be provided, which closes the opening of the tube body.
[0006] The connection element is usually connected to the hose using an adhesive. However, the use of adhesive has disadvantages. Apart from the additional costs for procurement and storage, adhesive also causes contamination of the production environment, so that cleaning and extraction systems are usually necessary. This is particularly true in the medical sector, where particularly strict hygienic conditions must be maintained during production. In recent years, adhesive dosing has been improved so that even very small quantities of adhesive can now be applied. Although this has reduced adhesive costs, the costs for the dispensing devices have increased. Cycle times are also relatively long, as it is necessary to wait until the adhesive has cured.In addition, both adhesives and operating materials required to clean surfaces are hazardous substances that contain high levels of solvents.
[0007] Based on the described prior art, it is therefore an object of the present invention to provide a method of the type mentioned at the outset which enables a connection between the hose body and the closing element without the use of adhesive. This object is achieved by a sonotrode for connecting a hose body which is open on at least one side to a closing element which is designed as a hollow body which is open on two sides, wherein the sonotrode has two sections which adjoin one another along a longitudinal axis of the sonotrode, namely a guide section arranged at the front and a processing section arranged at the rear, wherein the guide section has a smaller cross-section than the processing section and the processing section has a sealing surface which is intended to come into contact with the closing element and to transmit an ultrasonic vibration to the closing element.The sonotrode can push the closing element towards the hose body.
[0008] For the purposes of the present invention, a front section of the device is understood to mean a section which, compared to a rear section of the device, is arranged closer to the hose body to be connected and the closing element.
[0009] Sonotrodes are known in the art and are used to be imparted with an ultrasonic vibration and to transmit the ultrasonic vibration to the material to be processed due to contact of the sealing surface of the sonotrode with a material to be processed, ie in this case with the closing element.
[0010] The guide section therefore serves to hold the hose body while the processing section pushes the closure element toward the hose body. If the sonotrode is then subjected to an ultrasonic vibration, the material melts at the interface between the hose body and closure element, creating a solid connection between the hose body on the one hand and the closure element on the other. The guide section can prevent melt from entering the interior of the hose body. Preferably, the guide section has no sealing surface, so that the guide section transfers little or no energy to the closure element via the ultrasonic vibration.
[0011] In an alternative embodiment, it can be provided that the guide section has lateral surfaces which transfer energy to the hose body.
[0012] In a preferred embodiment, the sealing surface is annular. The sealing surface thus encloses the guide section. Alternatively, or in combination, the sealing surface can be designed such that it forms an angle of more than 0°, preferably more than 60°, particularly preferably more than 80°, and most preferably 90°, with the longitudinal axis.
[0013] Due to the movement of the sonotrode in the longitudinal direction, i.e. in the direction of the longitudinal axis, the sealing surface can exert a force on the closing element due to its inclination relative to the longitudinal axis.
[0014] The guide section can be cylindrical or conical, or have cylindrical or conical sections. This design has the advantage that the tube body can be reliably processed by the sonotrode even if it is not precisely aligned, as the conical shape guides the tube body accordingly and pushes it into the correct position.
[0015] In a further embodiment, the sonotrode has a terminal section arranged such that, viewed along the longitudinal axis, the processing section is located between the terminal section and the guide section, wherein the terminal section has a larger cross-section than the guide section. The terminal section can have the connection device on its end face facing away from the processing section. The terminal section can come into contact with the closure element. In a preferred embodiment, however, it does not come into contact with the closure element.
[0016] In a preferred embodiment, the processing section has a surface section adjoining the sealing surface, which is not in the same plane as the sealing surface. For example, the sealing surface can be oriented perpendicular to the longitudinal axis, and the adjoining surface section can be oriented parallel to the longitudinal axis. For example, the adjoining surface section can be formed by the lateral surface. The adjoining surface section can be designed and arranged relative to the closing element in such a way that it prevents melt from leaving the joining zone.
[0017] In a further embodiment, the processing section has a surface section which is shaped correspondingly to the closing element, so that the closing element is held stably in a certain position during processing and products of higher quality are manufactured.
[0018] In a preferred embodiment, the sonotrode has two end faces and a circumferential lateral surface connecting the two end faces. The guide section and the processing section each have an end face, and the end face arranged on the processing section has a connection device for connecting the sonotrode to an amplitude transformer or a converter. The connection device can consist of a threaded bore, for example. In other words, during operation, the guide section is arranged on the side of the sonotrode facing away from the converter or the amplitude transformer.
[0019] The converter converts an alternating electrical voltage into a mechanical ultrasonic vibration, which is then coupled to the sonotrode. If necessary, an amplitude transformer can be installed between the converter and the sonotrode to change the amplitude of the ultrasonic vibration.
[0020] According to the invention, the sonotrode is used in a method for connecting a hose body which is open at least on one side to a closure element, wherein the closure element is designed as a hollow body which is open on both sides and has a first closure element opening and a second closure element opening, wherein the method comprises the following steps:
[0021] A) Providing the hose body with an opening and providing the closing element,
[0022] B) Inserting the hose body into the first closing element opening of the closing element,
[0023] C) feeding a sonotrode according to one of the preceding claims through the second closure element opening into the closure element and feeding the guide section into the opening of the hose body,
[0024] D) Excitation of the sonotrode with an ultrasonic vibration
[0025] As in the prior art, the tube body is inserted into the closure element. However, the provision of adhesive is dispensed with. Instead, the specially shaped sonotrode is inserted into the closure element in such a way that the guide section reaches into the tube body, while the sealing surface comes into contact with the tube body and / or the closure element. In a preferred embodiment, it is provided that the tube body has a through-channel with a circular cross-section of area QH and that the guide section has a circular cross-section of area QF, at least at its end facing the processing section, where Q H > Q F , preferably 0.90 x Q H > Q F and particularly preferably 0.90 x Q H > Q F > 0.8 x Q H is.
[0026] In other words, the diameter of the guide section is approximately 5 to 10% smaller than the diameter of the hose body. It can be provided with a threading radius at the end facing away from the processing section to minimize damage to the hose body.
[0027] In a further preferred embodiment, during step D), the distance between the processing section, at least on the side facing the sealing surface, and the closure element is selected to be less than 0.5 mm, preferably less than 0.1 mm, and particularly preferably less than 0.06 mm. This ensures that no molten material flows along the outside of the processing section between the processing section and the closure element.
[0028] In a further preferred embodiment, a closing element with a stop element is used as the closing element, wherein the stop element is arranged within the closing element and connected to it. In this case, either in step B) the tube body can be inserted into the first opening of the closing element until the tube body rests against the stop element, or in step C) the sonotrode can be fed at least until the sealing surface of the sonotrode rests against the stop element. In a particularly preferred embodiment, the stop element is used both to limit the movement of the tube body within the first opening of the closing element in step B) and to limit the movement of the sonotrode in step C).
[0029] For example, the stop element can be made of a meltable material, preferably a thermoplastic material, and can be melted in step D) to create a connection between the tube body and the closure element. The stop element can be made of the same material as the closure element and formed integrally therewith. In a further preferred embodiment, it is provided that during step D), the stop element is arranged between an end face of the tube body surrounding the opening of the tube body and the sealing surface of the sonotrode.
[0030] As a result, the sealing surface of the sonotrode presses the stop element and thus also the closing element against the end face of the hose body, so that when the sonotrode is excited with an ultrasonic vibration, the material melts at this point and thus a firm connection is formed between the closing element on the one hand and the hose body on the other, without the need for adhesive.
[0031] Further advantages, features, and possible applications of the present invention will become clear from the following description of a preferred embodiment and the accompanying figures. They show:
[0032] Figure 1 is a sectional view through an embodiment of the sonotrode according to the invention and
[0033] Figure 2 shows a sectional view of the sonotrode inserted into the closing element shortly before the material of the closing element is melted.
[0034] Figure 1 shows a cross-sectional view of a sonotrode 1 according to the invention. The sonotrode has a guide section 2 of length l2 and a processing section 3 of length h. The processing section 3 in turn consists of two sections 5, 6, the front section 5 being a cylindrical section, while the rear section 6 is conical. A terminal section 7 adjoins the processing section 3 and in particular the section 6 of the processing section 3. The terminal section 7 has a threaded bore 4 on its rear end face, which is provided for connecting a converter or an amplitude transformer. At the end of the processing section 3 facing the guide section 2, an annular sealing surface 8 is provided, which encloses an angle of 90° with the longitudinal axis 9.
[0035] The end section 7 also has an annular end face 13 at its end facing the processing section 3, which also forms an angle of 90° with the longitudinal axis 9.
[0036] The use of the sonotrode according to the invention is explained with reference to Figure 2. The sonotrode according to the invention can be used to fasten a closing element 11 to a hose 10. Figure 2 shows that the closing element 11 has an inner diameter that approximately corresponds to the outer diameter of the hose 10, so that the hose 10 can be pushed into the closing element 11. The closing element 11 has a stop element 12 on its inner surface which, as can be seen in Figure 2, in the position shown rests on the end face of the hose 10 facing the sonotrode 1 and comes into contact with the sealing surface 8 of the sonotrode 1.
[0037] In a first step, the closing element 11 is therefore placed on the hose 10 until the stop element 12 rests on the end face of the hose 10.
[0038] The sonotrode 1 is then inserted into the closing element 11 through the opening opposite the tube 10, so that the guide element 2 is inserted into the tube 10. The sonotrode is fed toward the tube 10 until the sealing surface 8 of the processing element 3 rests against the stop element 12. The sonotrode is then excited by an ultrasonic vibration, which ensures that the stop element 12 melts at least on its side facing the tube body 10 and forms a bond with it, thereby ensuring that the closing element 11 is firmly connected to the tube 10.
[0039] Section 6 is configured to correspond to an inner surface of the closure element 11. Section 5 is set back from section 6 and should not come into contact with the closure element 11, since the closure element 11 has internal teeth that must not be damaged by the machining section, since the internal teeth are intended for connecting the closure element 11 to another element.
[0040] List of reference symbols
[0041] 1 sonotrode
[0042] 2 Guide section 3 Processing section
[0043] 4 threaded holes
[0044] 5 Section of the processing section
[0045] 6 Section of the processing section
[0046] 7 Final section 8 Sealing area
[0047] 9 Longitudinal axis
[0048] 10 hose bodies
[0049] 11 Final element
[0050] 12 Stop element 13 End face
Claims
Patent claims 1 . Sonotrode for connecting a hose body which is open on at least one side to a closing element which is designed as a hollow body which is open on both sides, wherein the sonotrode has two sections which adjoin one another in a longitudinal direction of the sonotrode, namely a guide section and a processing section, wherein the guide section has a smaller cross-section than the processing section and the processing section has a sealing surface which is intended to come into contact with the closing element and to transmit an ultrasonic vibration to the closing element.
2. Sonotrode according to claim 1, characterized in that the sealing surface is annular and / or encloses an angle of more than 0°, preferably of more than 60°, particularly preferably of more than 80° and most preferably of 90° with the longitudinal axis.
3. Sonotrode according to one of the preceding claims, characterized in that the guide section is cylindrical or conical or has cylindrical or conical sections.
4. Sonotrode according to one of the preceding claims, characterized in that the sonotrode has two end faces and a circumferential shell surface connecting the two end faces, wherein the guide section and the processing section each have an end face and the end face arranged on the processing section has a connection device for connecting the sonotrode to an amplitude transformer or a converter.
5. Sonotrode according to one of the preceding claims, characterized in that the sonotrode further comprises a terminal section which is arranged such that the processing section, viewed along the longitudinal axis, is arranged between the terminal section and the guide section, wherein the terminal section has a larger cross-section than the guide section.
6. Sonotrode according to the preceding claim, wherein the processing section has a section which is formed corresponding to a section of the closing element and is intended to come into contact with the closing element during processing.
7. A method for connecting a hose body which is open at least on one side to a closure element which is designed as a hollow body which is open on both sides and has a first closure element opening and a second closure element opening, comprising the steps: A) Providing the hose body with an opening and providing the closing element, B) Inserting the hose body into the first closing element opening of the closing element, C) feeding a sonotrode according to one of the preceding claims through the second closure element opening into the closure element and feeding the guide section into the opening of the hose body, D) Excitation of the sonotrode with an ultrasonic vibration.
8. Method according to claim 7, characterized in that the hose body has a through-channel with a circular cross-section of area QH, that the guide section has a circular cross-section of area QF at least at its end facing the processing section, where Q H > Q F , preferably 0.95 x Q H > Q F and particularly preferably 0.95 x Q H > Q F > 0.9 x Q H is.
9. Method according to claim 7 or 8, characterized in that during step D) the distance between the processing section at least on the side facing the sealing surface and the closing element is selected to be less than 0.5 mm, preferably less than 0.1 mm and particularly preferably less than 0.06 mm.
10. Method according to one of claims 7 to 9, characterized in that a closing element with a stop element is used as the closing element, wherein the stop element is arranged within the closing element, wherein in step B) the tube body is inserted into the first opening of the closing element until the tube body rests against the stop element and / or in step C) the sonotrode is fed at least until the sealing surface rests against the stop element.
11. The method according to claim 10, characterized in that the stop element consists of a meltable material, preferably of a thermoplastic material, and is melted in step D) and creates a connection between the hose body and the closing element.
12. The method according to claim 10 or 11, characterized in that during step D) the stop element is arranged between an end face of the tube body surrounding the opening of the tube body and the sealing surface of the sonotrode.