Connect two objects

Abstract

A method for connecting a first object (1) and a second object by means of a connecting element (3) is described. To anchor the connecting element relative to the first object, a tool (6) is used to press the connecting element against the first object into a first opening (13) of the first object (1), while mechanical vibration energy is coupled into the assembly comprising the first object and the connecting element. Here, the pressing surface of the tool abuts against the adjacent surface of the connecting element, which is located distal to the proximal end. Through the combined action of vibration energy and pressure, the thermoplastic material (36) of the distal portion of the connecting element (3) is made flowable and permeates the structure of the first object to create anchorage of the distal portion of the connecting element in the first object after re-curing. Subsequently, the second object is placed relative to the first object such that the proximal portion of the connecting element having a proximal end is inserted into a second opening, and the first and second objects are pressed against each other, while mechanical vibration energy is coupled into at least one of the first and second objects until the thermoplastic material of the proximal portion of the connecting element is made flowable and permeates the structure of the second object near the second opening to create anchorage in the second object after re-curing.

Description

Invention Field

[0001] This invention belongs to the fields of mechanical engineering and construction and relates to a method for connecting two objects by means of a connecting element, as well as a kit of connecting elements and parts. The connecting element comprises a material having thermoplastic properties, and the method includes applying energy, such as mechanical vibration, for example, ultrasonic vibration. Background of the Invention

[0003] WO 2006 / 002569 discloses a method for joining two objects, such as wood, by means of a connecting element comprising a thermoplastic material at least in its distal and proximal regions. Two opposing blind holes are disposed in the two objects, and the connecting element is located within the blind holes such that its distal and proximal ends contact the bottom surfaces of the blind holes. The length of the connecting element and the depth of the blind holes are matched to each other, such that a gap exists between the two objects in this case. The assembly is then positioned between a support and an ultrasonic welding electrode (sonotrode). When the ultrasonic welding electrode vibrates, the ultrasonic welding electrode and the support are forced toward each other. Consequently, a material, at least partially thermoplastic in nature, is liquefied where the end of the connecting element is pressed against the bottom surface of the hole. As a result, the liquefied material permeates into pores on the hole surface or into unevenness or openings provided in the hole surface. After the thermoplastic material re-solidifies, the end of the connecting element is thus anchored in the object. To achieve a suitably similar anchoring quality at the ends of the two connecting elements, the distal end of the connecting element has a smaller surface area and contains less thermoplastic material than the proximal end of the connecting element.

[0004] As an alternative to forcing the ultrasonic welding electrodes and non-vibrating supports to abut against each other, the supports can also be vibrated, i.e., the first and second objects are pressed together by two vibrating ultrasonic welding electrodes. Thus, the process is even more efficient than an asymmetric construction with only one vibrating support. In particular, in this construction, the connecting elements do not need to be asymmetric between the proximal and distal ends, but can be symmetrical, which simplifies the process.

[0005] In both asymmetric and symmetric connection elements, it can be difficult to control the flow characteristics of the connection element.

[0006] DE102009044210 discloses a method for securing a thermoplastic pin to a lightweight building panel, wherein the pin comprises a thermoplastic sheath and a stud of a different material. Securing to the panel can be accomplished in one step using ultrasonic energy, or alternatively in two steps, wherein in the first step, the sheath is anchored relative to the panel, and in the second step, the stud is welded to the sheath.

[0007] DE102018122399 discloses a method and apparatus for joining a first and a second component using an amalgamation plate. Here, the first and second components comprise a thermoplastic material, which is heated during the joining process until it melts, causing material from the components to flow through a portion of the amalgamation plate and solidify to hold the amalgamation plate relative to the components. Additionally, an adhesive that can contact the amalgamation plate can be applied between the first and second components. This method is only suitable for joining flat components of thermoplastic material to each other, and the amalgamation plate has a corresponding plate-like shape, having sharp structures protruding from both sides of the plate and being placed between the components. After this process, the sharp structures are embedded in the thermoplastic material; therefore, for this method of operation, it is important that they remain intact when heat is applied. All of these limitations restrict the possible applications taught in DE102018122399. Invention Overview

[0009] The object of this invention is to provide a method for connecting two objects by means of a connecting element, which overcomes at least some of the disadvantages of the prior art and provides reproducible results even when the properties of the objects to be connected are not entirely predictable. Another object is to provide a connecting element for this purpose and a kit of parts including such a connecting element.

[0010] According to one aspect of the invention, a method is provided for connecting a first object and a second object by means of a connecting element. The connecting element extends between a distal end and a proximal end and is made of a thermoplastic material. The first object has a first opening, such as a first opening of a first blind hole, and the second object has a second opening, such as a second opening of a second blind hole. Here, the first opening and / or the second opening can be formed before or during the process. Here, the depths of the two blind holes can be the same or different.

[0011] The method first includes providing a first object and positioning a connecting element relative to the first object. For example, the first object may have a first opening, and the positioning step then includes inserting a distal portion having the connecting element at its distal end into the first opening.

[0012] Then, to anchor the connecting element relative to the first object, a tool is used to press the connecting element against the first object into the first opening, while energy, such as mechanical vibration energy, is coupled into the assembly including the first object and the connecting element (i.e., coupled into the first object or the connecting element, or both). Here, the tool extends between a proximal tool end face and a distal tool end face, and during the step of coupling energy into the assembly, the proximal end of the connecting element is proximal to the distal tool end face, and the pressing surface of the tool abuts against the adjacent surface of the connecting element, which is distal to the proximal end. Through the combined action of energy and pressure, the thermoplastic material of the distal portion of the connecting element is allowed to flow and enter the structure of the first object near the first opening, so as to create anchorage of the distal portion of the connecting element in the first object after re-curing.

[0013] Subsequently, the second object is placed relative to the first object. The second object may have a second opening, and placement then results in the proximal portion of the connecting element having a proximal end being inserted into the second opening. In this configuration, the first and second openings may be aligned (aligned) with each other. A gap remains between the first and second objects after placement. The first and second objects are then pressed against each other, while mechanical vibration energy is coupled into at least one of the first and second objects, for example, at least into the second object, until the thermoplastic material of the proximal portion of the connecting element can flow and enter the structure of the second object near the second opening to create anchorage in the second object after re-curing.

[0014] Therefore, it is possible that after the process, the first and second openings, which can be aligned with each other, form a common hollow space in which the connecting element is located. The connecting element is anchored relative to both the first object in the first opening and the second object in the second opening, thereby the connecting element can be used as a kind of "hidden pin".

[0015] The connecting element may be, for example, pin-shaped, with a greater extension in the proximal direction than in other directions. In an alternative embodiment, the connecting element need not be entirely pin-shaped, but may include a first pin-shaped portion and a second pin-shaped portion formed by a distal portion and a proximal portion, respectively.

[0016] Specifically, the first object may have a proximal surface portion, and a first opening has an opening in the proximal surface portion. The second object may have a distal surface portion, and a second opening has an opening in the distal surface portion. After the step of placing the second object, the distal surface portion of the second object faces the proximal surface portion of the first object. After the step of pressing the first and second objects together, the proximal and distal surface portions are in physical contact with each other, or alternatively, a gap is maintained between these facing surface portions.

[0017] Therefore, in addition to this anchoring, the gap between the first and second objects can be closed by pressing the first and second objects against each other. In an alternative embodiment, the gap is not closed, but its size is reduced.

[0018] Therefore, contrary to the method taught in WO 2006 / 002569, the anchoring of the connecting element relative to the first object is separate from its anchoring relative to the second object. Thus, both anchoring steps can be performed in a well-defined manner and result in a connection with a well-defined amount of thermoplastic material that has been liquefied and re-cured, and result in well-defined shrinkage and / or other deformation of the connecting element, thus resulting in well-defined fixation—independent of whether the material properties and other parameters are equal between the first and second objects, and between different first objects / different second objects. This method is therefore particularly suitable for joining objects that have already been manufactured economically without any reproducible optimization.

[0019] However, even if the connecting element is first anchored in the first object, which involves pressing the connecting element to the distal side, the proximal portion of the connecting element, due to its proximity to the adjacent surface—and as described in more detail below—can maintain or even acquire a shape suitable for the second anchoring step in the second object during this first anchoring step.

[0020] Anchoring of the material in the first / second object by means of the connecting element flowing into and re-curing the structure of the first / second object can be at least partially achieved through a positive-fit connection, since the re-cured thermoplastic material cannot be pulled out of the structure it has penetrated without being damaged. Depending on the material of the first / second object, it may also include a material connection (integral joint) through a material-to-material bond between the thermoplastic material and the material of the first / second object.

[0021] The structure in which thermoplastic material flows into the first / second object may particularly include a structure that allows the thermoplastic material to permeate, especially an irregular structure of the first / second object. Alternatively or as an alternative, the structure may include a pre-formed cavity with an undercut, the cavity having a well-defined volume, substantially as described in WO2014 / 075200, particularly referring to... Figure 19 a, 19b and 20.

[0022] Possible design criteria for the connecting element involve the adjacent surfaces. In many embodiments, it may be advantageous if the total area of ​​the adjacent surfaces is greater than the area of ​​the distal end. This ensures that the melting process in the first anchoring step begins at the distal end in contact with the first object, rather than at the interface between the tool and the connecting element.

[0023] The methods described in this article have applications in furniture manufacturing, including both flat-pack furniture (i.e., furniture pieces assembled by the user) and pre-assembled furniture. Other applications include the construction industry, such as manufacturing doors, window frames, etc., and the manufacture of caravans and RVs. Other applications, such as in the automotive manufacturing industry or other industries, are also possible.

[0024] The tool can be an ultrasonic welding electrode, where the pressing surface is the external coupling surface. Then, at least a portion of the energy, which is mechanical vibration energy (e.g., all mechanical vibration energy), is coupled into the connecting element through the ultrasonic welding electrode, which vibrates when pressed against the connecting element.

[0025] In this group of embodiments, the ultrasonic welding electrode and the device that generates vibration and includes the ultrasonic welding electrode only need to be adapted to the shape and size of the connecting element, and the same connecting element can be used to connect different kinds of objects. In the first subgroup of embodiments of this group, the first object can be pressed against a non-vibrating support during the process of anchoring the connecting element in the first object. This includes the possibility of using a handheld device as a device that includes an ultrasonic welding electrode and further includes a vibration generator. In the second subgroup of embodiments, a portion of the vibrational energy can be directly coupled into the first object through the support, which is itself a vibrating ultrasonic welding electrode.

[0026] In one set of alternative embodiments, the tool can be a pressing tool, in which no vibration is coupled into the tool when it is pressed against the connecting element, and energy is coupled into the assembly in different ways. An example of such a different way is to use an ultrasonic welding electrode to couple vibrational energy into the first object during the step of pressing the connecting element distally with the tool. Other ways include using electromagnetic energy sources, such as lasers, coils for generating alternating magnetic fields, or electrodes, and, for example, providing the thermoplastic material with appropriate absorption properties through fillers.

[0027] The abutment surface of the connecting element faces proximally and may include, for example, at least a portion substantially perpendicular to the proximal-distal axis. The abutment surface may include a shoulder, such as an inner shoulder. It is also possible that the abutment surface has multiple abutment surface portions, such as an inner shoulder and an outer shoulder, and / or shoulders at different axial positions, such as shoulders arranged with multiple steps.

[0028] The tool that couples pressure into the connecting element has a distal extrusion face. If the tool is an ultrasonic welding electrode, the extrusion face is the coupling output face, through which vibrational energy is coupled from the ultrasonic welding electrode into the connecting element. The extrusion face can be a distal face or can be offset proximally relative to the distal ultrasonic welding electrode.

[0029] The tool may have a recess with an opening in its distal face, in which a proximal portion of the connecting element is received during the step of pressing the connecting element distally. If the proximal portion is hollow and tubular to form a proximal crown extending circumferentially around a central hollow space, then such a receiving recess may in particular have an annular cross-section to receive the proximal portion of the connecting element, the central hollow space being either axially extending across the central hollow space of the connecting element or being a proximal / distal recess of the connecting element. The radially inward portion of the receiving recess may then include a pressing surface or at least a portion thereof to cooperate with an adjacent surface located radially inward of the proximal portion and, for example, an inner shoulder, or the bottom surface of the proximal / distal recess.

[0030] Instead of extending circumferentially around the central hollow space in a continuous manner, the crown can be formed by multiple teeth extending around the central hollow space.

[0031] In addition to or as an alternative to the inner shoulder, the adjacent surface may include the outer shoulder.

[0032] Generally, the adjacent surface can be considered as the interaction zone between the tool and the connecting element, which is located on the far side of the proximal end of the connecting element.

[0033] In one embodiment, the shapes of the proximal portion of the connecting element and the distal recess of the tool are at least partially adapted to each other, such that the proximal portion abuts against the inner surface of the recess along most of its surface. In this configuration, different portions of surfaces at different angles to the axis can belong to adjacent surfaces.

[0034] Optionally, the recess of the tool of the type receiving the proximal portion can be used as a mold part, which is at least partially shaped for a subsequent step in which the proximal portion is used to secure a connecting element to the second object when the second object and the first object are pressed against each other, the connecting element being in a corresponding first opening and second opening.

[0035] This shaping of the proximal portion of the connecting element can also occur through a protrusion of the tool that extends beyond the proximal portion of the connecting element, for example, only on one side (such as only on the inside or only on the outside), during the step of pressing the connecting element to the distal side using the tool.

[0036] Regardless of whether the tool has a distal recess, the proximal portion of the adjacent surface can form a proximal crown that extends around a proximal-distal axis. This crown extends circumferentially around a central hollow space (which can be a hollow space axially passing through the connecting element or it can be a proximal recess). It can terminate proximally with a continuous edge, or it can be discontinuous, such that the crown has, for example, multiple teeth.

[0037] More generally, in many embodiments, the connecting element has a distal energy proximal feature at least after and, for example, before the extrusion step, which may include at least one proximal blade-like projection terminating at an edge and / or at least one tip. The proximal blade-like projection may be formed from a crown of the type described above.

[0038] The connecting element may also have a distal coronal portion. More generally, in many embodiments the connecting element has a distal energy-directing feature, which may include at least one distal blade-shaped projection terminating at an edge (e.g., formed by the distal end of the distal coronal portion or other, for example, blade-shaped distal projection features) and / or at least one tip.

[0039] Alternatively or as an alternative, at least after the tool used to press the connecting element distally (which, as mentioned, may optionally also be used to shape the proximal end) is removed, the proximal portion of the connecting element may have proximal energy-directing features, which may include at least one edge (e.g. formed through the proximal end of the proximal coronal portion) and / or at least one tip.

[0040] In one embodiment, the connecting element is symmetrical with respect to a median plane perpendicular to the proximal and distal axes, allowing the connecting element to be inserted into the first opening in either manner. However, similarly, even if the connecting element is substantially symmetrical, if it is hollow and tubular, the partition members extending laterally through the internal space can be arranged asymmetrically with respect to the median plane. Such partition members can be, for example, membrane-like or plate-like.

[0041] The connecting element may also include an energy guide on the outer surface. This energy guide is made of a thermoplastic material and may be, for example, ribs extending axially and uniformly distributed around the periphery. The diameter of the connecting element including these energy guides may be approximately equal to or slightly larger than the diameter of the first and / or second opening. These energy guiding ribs facilitate the liquefaction of the thermoplastic material portion of the connecting element in contact with the circumferential wall of the corresponding opening, thereby allowing the thermoplastic material portion to permeate the structure of the first and / or second object near the circumferential wall.

[0042] The first opening and / or the second opening may be blind holes, and the steps of pressing the connecting element distally and pressing the first and second objects together using a tool may include pressing the connecting element against the bottom surface of the first / second opening, respectively. The result after the connection process may include the thermoplastic material of the connecting element permeating the material of the first / second object at the respective bottom surface.

[0043] Alternatively, this is not necessary if the dimensions of the connecting elements and the corresponding openings are adapted to each other for press fit. Instead, anchoring can also occur around the circumferential wall, based on the principles taught in WO 2015 / 181300.

[0044] A specific set of embodiments relates to an implementation where the gap between the first and second objects does not close due to the objects pressing against each other, but rather the size of the gap simply decreases. Also in these embodiments, the first and / or second objects may each include a first opening / second opening into which the distal / proximal portion of the connecting element is inserted. Therefore, this gap differs from the gap that would occur if the element were simply placed between the flat surfaces of the first / second objects, because the element prevents physical contact between the first / second objects.

[0045] For example, the remaining gap can be used as an adhesive gap. In this way, the present invention can solve the problems of existing methods involving joining objects by adhesive bonding. Depending on the surface properties of the objects to be joined, adhesive bonds can be relatively strong and stable, but suffer from the disadvantage that they significantly delay the industrial manufacturing process, thus requiring a large amount of storage space for storing components during manufacturing until the bond hardens. The method according to the invention is characterized by the advantage that the bonding of the connecting elements ensures immediate initial stability, allowing for immediate further processing of the components of the first and second objects, and the adhesive can slowly harden in subsequent steps without delaying the process.

[0046] Other uses for the remaining gap may include arranging functional elements within the gap, such as hinges, anchoring points for connecting to another object, etc.

[0047] In this set of specific embodiments, the connecting element itself can be shaped to define the width of the remaining gap by including a spacer portion that laterally protrudes to form a stop surface for the first and second objects when they press against each other.

[0048] Alternatively, recesses may be provided in the first and second objects such that the functional element extends between the first and second objects without forming a gap, which means that the first and second objects are adjacent.

[0049] The concept of using a connecting element between a first object and a second object can be used independently of a two-step procedure including a first anchoring step (anchoring the connecting element relative to the first object) and a second anchoring step (pressing the second object against the first object via the connecting element), in which a gap is maintained between the first and second objects (the gap being specifically defined by the spacer portion of the connecting element). Conversely, the concept can also be used in arrangements where the anchoring of the connecting element relative to the first object and the anchoring of the connecting element relative to the second object occur simultaneously, for example, substantially as described in WO2006 / 002569.

[0050] Therefore, according to a further second aspect, the present invention relates to a method for connecting a first object and a second object by means of a connecting element, the method comprising the following steps:

[0051] - Provide a first object and a second object;

[0052] - Provide a connecting element that extends between a distal end and a proximal end and comprises a thermoplastic material;

[0053] - Positioning the connecting element relative to a first object and relative to a second object, such that, according to a first option, the distal end of the connecting element contacts the first object (and is anchored therein in the subsequent steps of compression and coupling vibrational energy into the assembly) and, according to a second option, the distal end of the connecting element is anchored in the second object (e.g., according to the first aspect, or alternatively according to a conventional method), such that the proximal end of the connecting element contacts the second object, and such that a gap exists between the first object and the second object, the gap having an initial gap width;

[0054] - Pressing a first object and a second object against each other while coupling mechanical vibration energy into at least one of the first object and the second object until a portion of the thermoplastic material belonging to the proximal portion of the connecting element becomes flowable and causes it to flow into the structure of the second object to create fixation between the connecting element and the second object after re-curing, said proximal portion including a proximal end.

[0055] -As a result of the step of pressing the first object and the second object against each other, the first object and the second object move toward each other until the gap has a smaller final gap width, which is different from zero.

[0056] According to the first option, the step of pressing the first and second objects against each other while simultaneously coupling mechanical vibrational energy into at least one of the first and second objects causes a portion of the thermoplastic material belonging to the distal portion of the connecting element to flow and cause it to flow into the structure of the first object to create fixation between the connecting element and the first object after re-curing, said distal portion including the distal end. Therefore, according to the first option of this second aspect, by pressing the first and second objects against each other upon energy impact, the connecting element is anchored substantially simultaneously relative to both the first and second objects.

[0057] The connecting element can be composed of a thermoplastic material. Connecting elements composed of thermoplastic materials can be manufactured in a cost-effective manner, such as by injection molding. Alternatively, in addition to a thermoplastic material, the connecting element may include a portion of a different material, such as a non-liquefiable material or a material that is only liquefiable at a significantly higher temperature (e.g., at least 50°C higher) than the thermoplastic material. This additional portion can be, for example, a core, particularly a metal core. It can make the connecting element more stable, for example, in absorbing shear forces between the first and second objects.

[0058] The properties of the connecting element discussed above with reference to the first aspect of the invention can also be applied to the connecting element according to the second aspect. In particular, the first aspect and the second aspect can be combined (a second alternative thereto).

[0059] The first and second objects may be made of wood or wood composites. More generally, the first and / or second objects may comprise wood-based materials such as particleboard, chipboard, cardboard, fiberboard such as high-density fiberboard (HDF) and medium-density fiberboard (MDF), or wood (also in the form of plywood). In this document, “particleboard” is also used to refer to any composite material made by mixing wood chips of any shape with an adhesive, regardless of the shape of the product, including, for example, oriented strand board (OSB).

[0060] More generally, in embodiments where a structure including a first object / second object is permeated by a thermoplastic material of a connecting element, the material of the first object and / or the second object is solid and permeable to the thermoplastic material when the latter is in a liquefied state (i.e., the corresponding first object / second object material is fibrous or porous, includes a permeable surface structure, or cannot completely resist such permeation under pressure). This permeable material can be rigid and substantially not elastic or flexible (lacking elastomeric properties). It also includes (actual or potential) spaces into which the liquefied material can flow or be pressed for anchoring. It is, for example, fibrous or porous or includes a permeable surface structure, which is manufactured, for example, by suitable machining or by coating (the actual space for permeation). Alternatively, the permeable material is capable of forming such spaces under the hydrostatic pressure of the liquefied thermoplastic material, meaning it may be impermeable or only permeable to a very small extent under ambient conditions. This property (having potential spaces for permeation) implies, for example, non-uniformity in terms of mechanical resistance. Examples of materials exhibiting this property are porous materials, whose pores are filled with composites or heterogeneous materials (such as wood) of materials that can be extruded from the pores, including soft and hard materials, where the interfacial adhesion between components is less than the force exerted by the permeable liquefied material. Therefore, permeable materials generally exhibit inhomogeneity in terms of their structure ("empty" spaces, such as pores, cavities, etc.) or their material composition (displaceable or separable materials).

[0061] In particular, the materials of the first and second objects are not only solid at ambient temperature, but also do not melt, or at least not to a considerable extent, under the applicable conditions when the first material penetrates the surface structure.

[0062] Before energy transfer, the thermoplastic material suitable for the connecting element is also a solid in the sense of the aforementioned permeable material. It preferably comprises a polymer phase (particularly based on C, P, S, or Si chains) that transforms from a solid to a liquid or flowable state above a critical temperature range, for example by melting, and reverts to a solid material when cooled again below the critical temperature range, whereby the viscosity of the solid phase is several orders of magnitude (at least three orders of magnitude) higher than that of the liquid phase. The thermoplastic material will generally comprise a polymer component that is not covalently cross-linked or cross-linked in a manner in which the cross-linking bonds reversibly open upon heating to or above the melting temperature range. The polymer material may also contain fillers, such as fibers or material particles, that do not possess thermoplastic properties or possess thermoplastic properties including a melting temperature range significantly higher than that of the base polymer.

[0063] Examples of thermoplastic materials suitable for the methods according to the invention are thermoplastic polymers, copolymers, or filled polymers, wherein the base polymer or copolymer is, for example, polyethylene, polypropylene, polyamides (especially polyamide 12, polyamide 11, polyamide 6, or polyamide 66), polyoxymethylene, polycarbonate urethane, polycarbonate or polyester carbonate, acrylonitrile butadiene styrene (ABS), acrylate-styrene-acrylonitrile (ASA), styrene-acrylonitrile, polyvinyl chloride, polystyrene or polyetherketone (PEEK), polyetherimide (PEI), polysulfone (PSU), poly(p-phenylene sulfide) (PPS), liquid crystal polymers (LCPs), etc. LCPs are particularly interesting because their rapid decrease in viscosity during melting allows them to penetrate into very fine spaces within permeable materials.

[0064] If the connecting element is made entirely of thermoplastic material, it may have a modulus of elasticity of at least 0.5 GPa or preferably at least 1.0 GPa (at ambient temperature).

[0065] The mechanical vibration or oscillation suitable for the method according to the invention preferably has a frequency of 2 to 200 kHz (even more preferably 10 to 100 kHz, or 20 to 40 kHz) and a vibration energy of 0.2 to 20 W per square millimeter of active surface. The vibrating tool (e.g., an ultrasonic welding electrode) is designed, for example, such that its contact surface oscillates primarily in the direction of the tool axis (longitudinal vibration) with an amplitude of 1 to 100 μm, preferably about 30 to 60 μm. This preferred vibration is generated, for example, by an ultrasonic device known from ultrasonic welding.

[0066] According to a further third aspect, which is a modification of the first aspect, for the first anchoring step, a process substantially as described in WO 2016 / 071 335 is used. Here, the first object has a thermoplastic material, and the connecting element has a structure permeable to the material of the first object, such that the material of the first object is flowable due to an energy impact and causes it to permeate the structure of the connecting element to create anchorage of the connecting element in the first object after re-curing.

[0067] Therefore, the method according to the third aspect can be a method of connecting the first object and the second object by means of a connecting element, the method comprising the following steps:

[0068] - Provide a first object, the first object comprising a solid thermoplastic liquefiable material;

[0069] - Provides a connecting element extending between a distal end and a proximal end, the connecting element including a distal portion having a distal end, the distal portion including a surface portion having an undercut coupling structure and / or deformable to include such an undercut coupling structure, whereby the distal portion can form a positive-fit connection with a first object, and the connecting element including a proximal portion comprising a thermoplastic material;

[0070] - Positioning connection element relative to the first object;

[0071] - Using a tool, the connecting element is pressed distally relative to the first object, while energy is coupled into the first object and / or the connecting element until the flow portion of the thermoplastic material of the first object is liquefied and flows into the coupling structure of the connecting element to create anchorage of the distal portion of the connecting element in the first object after re-curing.

[0072] During the step of coupling energy into the first object and / or connecting element, the extrusion surface of the tool abuts against the adjacent surface of the connecting element, which is located on the far side of the proximal end.

[0073] - Provide a second object;

[0074] - Place the second object relative to the first object; and

[0075] - Pressing a first object and a second object against each other while coupling mechanical vibration energy into at least one of the first object and the second object until a second portion of the thermoplastic material belonging to the proximal portion of the connecting element becomes flowable and causes it to flow into the structure of the second object to create fixation between the connecting element and the second object after re-curing, said proximal portion including a proximal end.

[0076] For this purpose, the distal portion of the connecting element can be specifically configured to be anchored in the thermoplastic first object, for example, by means of a material that is non-liquefiable under conditions present during the first anchoring step. For example, the material of the distal portion can be metallic. The structure of the distal portion can be of any type described in WO 2016 / 071 335, which relates to the second object, or in WO 2019 / 197 501, which relates to the connector. The proximal portion can be configured as described with reference to any embodiment of the first aspect of the invention and as described herein.

[0077] The invention also relates to connecting elements having properties that make them usable in the methods described herein. In particular, such connecting elements may have any characteristics or combinations of characteristics of connecting elements used in the methods described herein.

[0078] Furthermore, the present invention relates to a kit of parts comprising a tool (ultrasonic welding electrode) for this method and one or more connecting elements.

[0079] The ultrasonic welding electrode used in the second anchoring step, where the first and second objects press against each other, can be a different ultrasonic welding electrode, for example, an ultrasonic welding electrode with a larger outer coupling surface than the ultrasonic welding electrode used in the first anchoring step. However, it is also possible to use the same first ultrasonic welding electrode again in the second step.

[0080] The device coupled to the first ultrasonic welding electrode may optionally be a handheld device, and the pressure applied to press the connecting element distally against the first object is manually generated. However, the device may optionally be more complex and include a working frame and a mechanism for generating the pressure. In any case, the manufacturing facility may include other equipment, including conveying equipment for transferring the first and second objects, as well as components, feeding equipment, etc., produced after the process.

[0081] In this document, the terms “radial” and “axial” should be understood as relating to the proximal-distal axis, which may coincide with the corresponding opening axis of the first / second opening during the process. Brief description of the attached diagram

[0083] The invention and its embodiments are described in further detail with reference to the accompanying drawings, which are schematic. The same reference numerals denote the same or similar elements. In the drawings:

[0084] Figure 1 The construction of the first object, connector, and ultrasonic welding electrode is illustrated using cross-sectional views;

[0085] Figure 2 Shown during the first anchoring step Figure 1 The structure;

[0086] Figure 3 Depicting a second object during the second anchoring step. Figure 1 and 2 The structure;

[0087] Figure 4-8 Details of the proximal portion of the connecting element are shown. Figure 4 , 5 Details of the distal portion of the ultrasonic welding electrode are shown in both 7 and 8;

[0088] Figure 9 and 10 The connecting elements are shown in longitudinal sectional view and side view, respectively;

[0089] Figure 11 Depicting at different scales for Figure 9 and 10 The ultrasonic welding electrode 11 of the connecting element;

[0090] Figure 12 Describe the details of the distal portion of the connecting element and the opening in the first object;

[0091] Figure 13 Explain alternative connecting elements that are not hollow;

[0092] Figure 14 and 15 Explain the arrangement of the first object, the second object, and the two connecting elements;

[0093] Figure 16 and 17 The alternative constructions before the first anchoring step and the alternative constructions before the second anchoring step are described respectively.

[0094] Figure 18 The diagram shows something similar to the one used for the first anchoring step. Figure 1 The structure is different, but the first object material is different and the connecting elements are adapted accordingly;

[0095] Figure 19 A further construction of the first object, the second object, and the connecting element is shown during the second anchoring step, with different second object materials and correspondingly adapted connecting elements;

[0096] Figure 20Describe connecting elements with spaced portions;

[0097] Figure 21 It shows a feature for defining adhesive gaps. Figure 20 The construction of the connecting elements;

[0098] Figure 22 and 23 This describes further variations of the connecting elements; and

[0099] Figure 24 An example of the third aspect of the invention is shown.

[0100] Description of preferred implementation scheme

[0101] Figure 1 The first object 1 is shown, which has a proximal surface 11 and a blind hole 13, the blind hole 13 having an opening in the proximal surface 11 and having a bottom surface 14 and a circumferential surface 15.

[0102] The first object shown here is a wood composite board, the proximal surface of which is the large side surface of the board. However, the teachings of referring to the depicted figures apply to the first and second objects of any shape, as well as to openings in any location, including blind holes in the small side surfaces of the board.

[0103] Figure 1 It is also described that the connecting element 3 is typically hollow and tubular, forming an internal hollow space 40, and is, for example, substantially symmetrical about the proximal and distal axes 30, with possible exceptions being energy-guiding ribs extending along the outer surface, as described below. The thickness of the tube forming the connecting element 3 decreases continuously towards the distal and proximal ends, i.e., it gradually tapers towards the distal and proximal ends, such that the distal end 33 and the proximal end 34 each form an edge.

[0104] The shape of the connecting element, which has a distal portion that tapers toward the distal edge, also ensures that the design criteria mentioned above are met, namely that the area of ​​the adjacent surface 37 (see also the description below) is greater than the interface area between the distal end 33 of the connecting element and the bottom of the blind hole in the first object.

[0105] In the depicted embodiment, the connecting element is asymmetrical with respect to the intermediate plane perpendicular to the proximal-distal axis 30 because the distal portion 31 and the proximal portion 32 have different shapes. Alternatively, the connecting element may also be symmetrical with respect to this plane.

[0106] The distal portion 31 and the proximal portion 32 each form a crown for anchoring the connecting element in the first object 1 and the second object 2, as described below.

[0107] Figure 1The tool serving as the first ultrasonic welding electrode 6 is also described. The first ultrasonic welding electrode 6 forms a distal end face 61 and a distal recess 63 in the distal end face, the distal recess 63 having a shape adapted to the proximal portion 32 of the connecting element 3 so as to receive the proximal portion.

[0108] Figure 4 Details of the proximal portion 32 of the connecting element and the distal portion of the ultrasonic welding electrode 6 are shown. The inner shoulder facing proximally forms an abutment surface 37. When the ultrasonic welding electrode presses distally against the connecting element, the interior 64 of the ultrasonic welding electrode presses against the abutment surface, thereby coupling pressure and vibrational energy into the connecting element, while the proximal crown portion located on the abutment surface 37 and received in the distal recess 63 does not deform. The area around the abutment surface thus serves as a force and energy receiving area.

[0109] exist Figure 4 In the diagram, the abutment surface 37 is illustrated as perpendicular to the proximal and distal axes. However, it is also possible to construct the abutment surface as slightly inclined, forming an outward or inward tapered shape, so that during the process, the pressure generates slightly inward or outward forces on the connecting element, respectively. More generally, the abutment surface can have any shape suitable for absorbing pressure, and if the tool is an ultrasonic welding electrode, it is suitable for transmitting mechanical vibration energy together with the outer coupling surface of the ultrasonic welding electrode. This includes the possibility, as discussed above, that the abutment surface includes several independent parts such as several steps, an outer shoulder and an inner shoulder, portions distributed around the circumference, etc.

[0110] Back Figure 1 The structure shown and referenced Figure 2 To anchor the connecting element in the first object, an ultrasonic welding electrode is used to press the connecting element against the first object, with its distal end abutting against the bottom surface 14, until the flow portion 36 of the thermoplastic material of the connecting element becomes flowable and is pressed into the structure of the first object around the bottom surface. As a result, after re-curing, the connecting element is anchored in the first object by a positive-fit connection, essentially as described, for example, in WO 98 / 42988.

[0111] Figure 2 Support 7 is also schematically illustrated. Generally, the support can be a non-vibrating support, such as formed, for example, by a worktable, in which the proximal and distal axes will be vertically oriented, or formed by different fixed or movable non-vibrating elements. Alternatively, the support itself may be capable of coupling vibrational energy into the assembly and thus forming the ultrasonic welding electrode itself. According to this alternative, instead of the ultrasonic welding electrode shown in all embodiments herein, the tool may also be used simply as an extrusion tool.

[0112] Figure 3An assembly of a first object 1 and a connecting element 3 anchored therein, and a second object 2, is shown. The second object has a second blind hole 23, which has an opening in its distal surface 21. To connect the second object 2 to the first object, the second object is positioned relative to the first object with its distal surface 21 facing the proximal surface 11 of the first object, and its proximal portion 32 is at least partially inserted into the second blind hole 23. For the connection process, the two objects and the assembly of the connecting element positioned in the blind hole are placed between the ultrasonic welding electrode 106 and the support 7. Here, the ultrasonic welding electrode may be the first ultrasonic welding electrode 6 used in the previous step of anchoring the connecting element in the first object, or as... Figure 3 As shown, it can be a different second ultrasonic welding electrode 106. The same applies to the support 7: the support 7 can be the same support or it can be a different support—for example, depending on whether the first object is moved from the first worktable to the second worktable between the step of anchoring the connector and the step of connecting the second object.

[0113] Similarly, in the second anchoring step, i.e., the step of connecting the second object to the first object, the support 7 can be a non-vibrating support, or it can be vibrating. For example, the support 7 can be a workbench or the like. Alternatively, for example, the configuration in this step may be symmetrical, with the support 7 being an ultrasonic welding electrode acting from one horizontal side, and the (second) ultrasonic welding electrode acting from the opposite horizontal side.

[0114] Under the pressure between the ultrasonic welding electrode 106 and the support member 7, the proximal end of the connecting element 3 is pressed against the bottom surface 24 of the second blind hole 23. Due to the mechanical vibration energy simultaneously coupled to the second ultrasonic welding electrode 106, the (second) flow portion 37 of the connecting element becomes flowable and is pressed into the structure of the second object. Here, the fact that the proximal end of the connecting element forms a proximal crown terminating at the proximal edge and thus has energy-directing properties ensures that energy absorption mainly occurs at the proximal end of the connector. It is possible that some energy absorption may also occur at the distal end of the connector, causing the thermoplastic material there to also be heated.

[0115] In the depicted configuration, the extrusion step and the step of coupling vibrational energy into the second object continue until the gap between the surfaces 11, 21 of the first and second objects closes. The vibration generating device control can be configured to detect when further forward movement of the ultrasonic welding electrode relative to the first object toward the distal side is no longer possible, and is then configured to automatically stop the vibrational energy input. Optionally, the device can be configured to apply post-pressure for a period of time, e.g., 0.3-3 s, to allow the thermoplastic material to harden to a certain degree before the ultrasonic welding electrode is removed.

[0116] The result of this process is that the first and second objects are connected by a connecting element that acts as a hidden pin, a process that is efficient and has excellent anchoring strength.

[0117] Multiple connecting elements can also be anchored in a corresponding number of first blind hole openings in the first object, and then the second object can be simultaneously bonded to these connecting elements using a sufficiently powerful device and a sufficiently large second ultrasonic welding electrode to simultaneously liquefy the material of the proximal portions of these connecting elements.

[0118] Figure 3 Further possible design criteria suitable for any implementation are described. Specifically, the dimensions of the connecting element 3 and the anchoring depth achieved in the first anchoring step, and the depths of the blind holes 13, 23 in the first and second objects, define the width d1 of the gap. This gap width d1 can be selected relative to the axial extension d2 of the proximal portion (the extension between the abutment surface 37 and the proximal end 34). In particular, for deep anchoring, the gap width can be approximately equal to and, for example, slightly greater than this axial extension.

[0119] In an embodiment where the crown is formed on the proximal portion, the entire crown will penetrate into the material of the second object to ensure a strong and reproducible anchorage.

[0120] Figure 5 The proximal portion 32 of the connecting element and the distal portion of a variant of the first ultrasonic welding electrode 6 are described. In this variant, the first ultrasonic welding electrode has a distal end with a reduced diameter, which fits into the interior of the proximal end of the connecting element to mate with the adjacent surface 37. In this embodiment, the first ultrasonic welding electrode 6 does not require a recess for accommodating the crown portion of the connecting element.

[0121] exist Figure 6 In the variant, the abutment surface 37 is not the inner shoulder, but the outer shoulder. Although the construction having an inner shoulder forming the abutment surface has the advantages of the crown (and proximal edge 34) having a potentially larger diameter and the possibility of having more liquefied material, as well as the advantage of the outer surface of the proximal portion facilitating anchoring (see below), the presence of an abutment surface in which the outer shoulder forms may also be an advantageous construction.

[0122] Combinations of outer and inner shoulders (located on the same or different axes) are possible. Similarly, staggered arrangements of shoulders forming adjacent surfaces together or structures with inclined adjacent surface portions are also possible.

[0123] exist Figure 1-5 In one embodiment, the receiving opening 63 is illustrated as being shaped such that there is substantially no physical contact between the proximal crown of the connecting element and the inner surface of the receiving opening.

[0124] Figure 7An alternative embodiment is shown in which the shapes of the receiving opening 63 and the proximal portion 32 of the connecting element are adapted to each other, such that the crown is precisely fitted into the receiving opening. This results in a tighter contact between the ultrasonic welding electrode and the connecting element, and can ultimately improve product efficiency. Furthermore, the relative positions of the ultrasonic welding electrode and the connecting element are more precisely defined during the process, thereby reducing the risk of proximal damage to the connecting element during the process.

[0125] The specific shape of the receiving opening of the ultrasonic welding electrode can also be used to intentionally make the distal portion of the connecting element this shape. This is in Figure 8 The diagram is schematically illustrated (in a slightly exaggerated manner). The connecting element shown has a blunt proximal end, and the shape of the receiving opening 63 corresponds to the shape of the tapered crown terminating at the edge. When the ultrasonic welding electrode 6 is pressed against the connecting element, and the proximal end of the connecting element is inserted into the receiving opening 63, the thermoplastic material at the proximal end softens and flows relative to the ultrasonic welding electrode, thereby the receiving opening (or at least its proximal portion) acts as a mold for shaping the connecting element for subsequent steps of attachment to a second object.

[0126] Generally, especially if the crown is relatively thin compared to its axial extension, i.e., if the crown is fragile, the implementation where the receiving opening of the ultrasonic welding electrode is used as a mold may be advantageous. This is likely the case, for example, if the second object is relatively soft or is itself a fragile structure, whereby the energy absorbed during the second anchoring step is limited, but sufficient anchoring depth is still required. In the case of a fragile crown shape, the prefabricated proximal crown, capable of free vibration, may have already been damaged in the first anchoring step. The method of using the receiving opening of the ultrasonic welding electrode as a mold effectively addresses this problem.

[0127] Figure 9 The longitudinal section of connecting element 3 is shown. Figure 10 This shows a view of the connecting element from a proximal perspective. (Except for reference...) Figure 1-5 In addition to the embodiments described in section 7, the connecting element 3 has the following features, which are independent of each other, i.e., these features can be implemented individually or in combination:

[0128] The connecting element has axially extending ribs 41 distributed circumferentially. These ribs have guiding properties. The diameter of the connecting element including these energy-guiding ribs can be approximately equal to or slightly larger than the diameter of the blind holes 13, 23. These energy-guiding ribs not only facilitate the liquefaction of the thermoplastic material of the connecting element in physical contact with the bottom surface of the blind hole, but also facilitate the liquefaction of the thermoplastic material of the connecting element in contact with the circumferential wall, whereby the thermoplastic material also permeates the structure of the first and / or second objects near the circumferential wall of the blind hole to facilitate anchoring within these walls.

[0129] The connecting element has a proximal shoulder in the region forming the proximal portion of the abutment surface 37, and a distal shoulder 38 in the corresponding distal position. Therefore, the connecting element can also be inserted into a blind hole opening in the first object with the opposite configuration, i.e., the proximal and distal portions are interchanged. For example, the connecting element can be symmetrical with respect to a mid-plane perpendicular to the proximal and distal axes, with possible exceptions being the partition wall or partition membrane described below.

[0130] The connecting element has a separating member 43, which has the shape of a wall or separating membrane extending laterally across the hollow space 40. This separating member 43 may initially function to assist in the process of removing the tool (ultrasonic welding electrode 6) from the connecting element after it has been anchored in the first object. Here, a temporary air overpressure may occur between the ultrasonic welding electrode 6 and the separating member 43 when the ultrasonic welding electrode 6 is retracted. Alternatively, the separating member 43 may allow for an air-based feeding system in which air pressure is used to feed / position the connecting element. Alternatively, the separating member 43 may be used to enhance the effectiveness of the coupling input of mechanical vibration energy, as it forms part of an abutment surface (abutment surface portion 39) and cooperates with the correspondingly shaped coupling output surface portion 66 of the ultrasonic welding electrode (see description below). Figure 11 ).

[0131] In addition to having an inner cone 47, the connecting elements in the distal and proximal portions 31 and 32 also have an outer cone 48, such that the outer diameter of the connecting element gradually decreases toward the distal and proximal edges.

[0132] As described above, if the shape of the receiving opening 63 is adapted to the proximal portion 32 of the connecting element and / or used to shape that proximal portion, removing the first ultrasonic welding electrode after anchoring the connecting element relative to the first object can be particularly problematic. In an effective process, it may be desirable to remove the ultrasonic welding electrode before the thermoplastic material has fully hardened, and it must be ensured that the adhesion between the ultrasonic welding electrode and the connecting element does not loosen the anchoring in the first object and / or, in that case, distort the shape of the connecting element. In addition to or as an alternative to using air blowing, mechanical elements (such as ejector plungers) can be used for this purpose, and / or the ultrasonic welding electrode can be activated by coupling vibration into it, or the ultrasonic welding electrode can be kept activated during removal.

[0133] Figure 11 An example of an ultrasonic welding electrode is shown, the shape of which is adapted to... Figure 9 and 10 The shape of the connecting element. Figure 11In one embodiment, in addition to the outer coupling surface 65 cooperating with the shoulder 37 forming the adjacent surface (or its proximal portion), the ultrasonic welding electrode has a second outer coupling surface 66 positioned centrally relative to the axis, which is positioned to press against the second shoulder of the separating member 43 (if any) or the connecting element. However, Figure 11 The ultrasonic welding electrode operates independently of the partition member or the presence of this second shoulder. In the depicted embodiment, the outer coupling surface 65 and, for example, a (optional) second outer coupling surface 66 are offset proximally relative to the distal surface 61.

[0134] Figure 12 This illustrates the principle that the connecting element does not need to be positioned against the bottom surface of the blind hole opening 13. In fact, the opening in the first object 1 (and similarly, the opening in the second object) does not even need to be a blind hole opening. Figure 12 In the diagram, the opening is shown as having a diameter d. r A deep blind hole opening. If the distal portion of the connecting element is inserted into the opening, the dimensions of the connecting element are suitable for a press fit (interference fit). For this purpose, the outer diameter d j Slightly larger than the diameter d of the opening r .

[0135] For example, WO 2015 / 181300 describes a method for anchoring the insert in the opening by liquefying a thermoplastic material through the transmission of mechanical vibration energy after establishing an interference fit, and by allowing the structure around the opening to interpenetrate through the thermoplastic material.

[0136] Figure 13 Another embodiment of the connecting element is illustrated schematically, which has the same characteristics as... Figure 9 and 10 The connecting elements have different and independent characteristics, namely:

[0137] The connecting element 3 is not hollow and tubular, but has a complete cross-section forming distal and proximal recesses 44, 45. This complete connecting element requires more material and has a more rigid nature. In some embodiments, this enhanced rigidity may be advantageous, for example, if significant shear forces are expected between the first and second objects. Similarly, the bottom surface of the proximal recess 45 (which, in the case of a symmetrical connecting element, may be indistinguishable from the distal recess) can serve as a stable abutment surface or a portion thereof.

[0138] • In addition to having a complete cross-section, or as an alternative to having a complete cross-section, the connecting element may have a portion 49 made of a material different from that of a thermoplastic material, such as a metal portion 49. Such a metal part, such as a metal core, can contribute to the mechanical stability of the connecting element and make the connecting element suitable for situations requiring the absorption of very strong shear forces between the first and second objects.

[0139] Figure 14 and 15 This is to illustrate, in a very illustrative way, that the method according to the invention is particularly suitable for constructions where the first and second objects have different properties in terms of material composition, shape, size, orientation, etc. Figure 14 and 15 In the schematic front and side views, the openings (blind hole openings) for the two connecting elements 3 are located on the small side of the first object and the large side of the second object, respectively.

[0140] Figure 14 and 15 It also illustrates, quite illustratively, that at least the second anchoring step can be performed simultaneously on multiple ( Figure 14 The parallel process (as shown in / 15 for two connecting elements) is performed in the second anchoring step, where the first and second objects are pressed against each other, and the (multiple) connecting elements are already anchored relative to the first object. The parallel process is also an option for the first anchoring step, especially if it is not performed using a handheld tool.

[0141] For example Figure 14 and 15 The process described, in which multiple connecting elements are connected to a second object at a time, allows for the simultaneous use of multiple ultrasonic welding electrodes (e.g., one ultrasonic welding electrode per connecting element). When the connecting elements are placed close to each other, a single ultrasonic welding electrode can also be used to couple energy simultaneously to more than one connecting element.

[0142] The embodiments described above include openings in both the first and second objects, i.e., blind holes in the illustrated embodiments. This is not necessary, depending on the nature of the first and second objects. Conversely, either the first or second object, or both, may not have any such blind hole openings, and the corresponding anchoring steps may include pressing the connecting element through the surface of the first / second object into the first / second object without any pre-fabricated openings. This principle is referenced... Figure 16 and 17The diagram illustrates that both the first and second objects are shown without any openings and are depicted as distinct lightweight building elements, i.e., sandwich panels. However, it also applies to cases where one of the objects has an opening, and it applies to the construction of the first and / or second objects having a structure different from that of a sandwich panel.

[0143] Figure 16 A first object 1, shown as a lightweight building element, has a first proximal outer building layer 101, a second distal outer building layer 102, and an inner liner 103. The density and material hardness of the inner liner 103 are significantly lower than those of the outer building layers 101 and 102. The first object has no openings.

[0144] For example, as described above, when the ultrasonic welding electrode 6 is used to press the connector 3 against the first outer building layer by pressing the outer coupling surface 65 against the adjacent surface 37, the connecting element is pushed through the surface of the first object. For example, the distal edge 33 may be stamped out of a portion of the first outer building layer 101, with or without mechanical vibration energy input during stamping, essentially as described in WO 2017 / 162693. More generally, if the first object is a lightweight building element with a sandwich structure, the distal end of the connecting member is used to pierce the first outer building layer.

[0145] Subsequently, the connecting element advances toward the distal end into the material of the first object, and the thermoplastic material of the distal portion liquefies upon structural contact with the first outer building layer, the inner liner, and / or the second outer building layer.

[0146] Figure 17 The final arrangement is shown, along with the second object 2 and the second ultrasonic welding electrode 106. The second object 2 is also a lightweight building element having first and second outer building layers 201, 202 and an inner liner 203 with lower density and strength. The second object 2 is also shown without any openings.

[0147] However, optional openings 223 consisting only of partially removed first outer building layer 202 are also depicted in cases where the proximal edge 34 of the connecting element is not sharp enough and / or stable enough to pierce the second outer building layer 202 of the second object, and / or where the anchoring of the connecting element in the first object is not stable enough and / or the second object as a whole does not have sufficient stability. The opposite case (where the first object has a partially removed first outer building layer, while the second object does not) is also possible.

[0148] In the aforementioned embodiments, the materials of the first and second objects are shown to be rigid and dimensionally stable (possibly except...). Figure 16 (Outside the inner lining 103 of the lightweight building element in the example). This is not required. Figure 18A first object 1, such as expanded polypropylene (EPP) foam, is shown as a relatively soft foam. The distal end of the connecting element can then have a correspondingly adapted structure for anchoring in a softer, compressible material, for example, as described in WO 2018 / 85, for example, with reference to... Figure 4-9 28, 34-47. Considering the compression of the first object during the first anchoring step, the blind hole in the first object may have a reduced depth; depending on the circumstances, the blind hole in the first object may even be omitted.

[0149] Figure 19 A variation is shown in which, instead of the first object, the second object 2 is made of a relatively soft material, shown here as a fibrous material. Here, the proximal end of the connecting element may have a correspondingly adapted structure, such as as described in WO 2018 / 85, for example, referencing... Figure 4-9 28, 34-47.

[0150] like Figure 19 The described configuration, in which the second object is made of a softer material than the first object, is also an example of an implementation in which vibrational energy for the second anchoring step is coupled from the first object side into the assembly, as shown by the (second) ultrasonic welding electrode 106 pressing against the back side (far surface) of the first object, while the assembly presses against the non-vibrational support 7 located near the second object 2. The vibration is coupled through the first object 1 and the connecting element 3 to the interface between the connecting element 3 and the second object 2.

[0151] Figure 20 A connector applicable in both the first and second aspects of the invention is shown. Essentially as described above, the connector has a distal portion 31 and a proximal portion 32, and also has a laterally projecting spacer portion 131. Figure 21 As explained, the spacer portion 131 can be used to define the remaining gap between the first object and the second object 1, 2. During the step of pressing the first object and the second object against each other, the spacer portion prevents the first object and the second object from moving towards each other. The width of the remaining gap corresponds to the thickness of the spacer portion.

[0152] Adhesive 140 can be applied before (or after) the step of pressing the first and second objects together, thereby leaving a gap for use as an adhesive gap.

[0153] The remaining gaps may also have other uses. Basically, as described above, Figure 22 The connecting element 3 is illustrated schematically. The connecting element 3 has a distal portion 31 and a proximal portion 32, and also has a lateral hinge 150, to which another object or structure (not shown) can be connected via a rotating portion 151.

[0154] If, in the intermediate position (with the distal and proximal portions aligned), the hinge provides sufficient axial stiffness for the (second or sole) anchoring step to occur, a hinge can also exist between the distal and proximal portions. Thus, the first and second objects can be rotatably connected to each other, which has interesting applications in door, window, or furniture manufacturing.

[0155] Figure 23 The possibility of providing an additional connection structure 161 for connecting elements, which is used to connect a third object to an assembly of a first and a second object, is illustrated very schematically. The additional connection structure is shown as another anchoring structure of the type of distal and proximal portions 31, 32. However, any connector structure can be used, including conventional structures such as threads.

[0156] exist Figure 22 and 23 In the diagram, arrow 's' indicates the width of the interval portion that defines the remaining gap width.

[0157] Figure 20-23 The connecting element can also be used in methods that deviate from the first aspect but conform to the second aspect.

[0158] Figure 24 The structure includes a first object 1, a connecting element 3, and an ultrasonic welding electrode 6 for performing a first anchoring step in the method according to a third aspect of the invention. The connecting element includes a distal portion 311 that is metallic and a proximal portion 32 that is thermoplastic, the proximal portion 32 being configured substantially as described with respect to the connecting elements of the first and second aspects.

[0159] Similar to the first aspect, the first anchoring step is essentially as described in WO 2016 / 0713 335, but is performed using an ultrasonic welding electrode abutting the adjacent surface of the connecting element, which is located distal to the proximal end. For this purpose, the ultrasonic welding electrode 6 and the proximal portion 32 can be shaped and constructed as in any embodiment of the first aspect, while the distal portion 311 is different and can have the structure and construction as in any embodiment of the second object described in WO 2016 / 071335. The second anchoring step is then performed as in the first aspect. All the choices and features associated with the second anchoring step according to the first aspect, and all the features and choices associated with the proximal portion of the connecting element for the first aspect, are equally applicable to the third aspect as options.

Claims

1. A method for connecting first and second objects by means of a connecting element, the method comprising the following steps: -Provide the first object; - Provide a connecting element that extends between a distal end and a proximal end and comprises a thermoplastic material; - Positioning connection element relative to the first object; - Using a tool, the connecting element is pressed distally relative to the first object while coupling energy into the first object and / or the connecting element until a first portion of the thermoplastic material belonging to the distal portion of the connecting element becomes flowable and causes it to flow into the structure of the first object to create anchorage of the distal portion of the connecting element in the first object after re-curing, the distal portion including the distal end. During the step of coupling energy into the first object and / or connecting element, the extrusion surface of the tool abuts against the adjacent surface of the connecting element, the adjacent surface being located on the distal side of the proximal end. - Provide a second object; - After a first portion of the thermoplastic material has flowed into the structure of the first object, a second object is placed relative to the first object; and - Pressing a first and a second object against each other while coupling mechanical vibration energy into at least one of the first and second objects, until a second portion of the thermoplastic material belonging to the proximal portion of the connecting element becomes flowable and causes it to flow into the structure of the second object to create fixation between the connecting element and the second object after re-curing, said proximal portion including a proximal end. The second object has a second opening, which is a blind hole. In the step of placing the second object relative to the first object, the second object is placed such that the proximal portion of the connecting element is inserted into the second opening. The step of pressing the first object and the second object against each other causes the proximal end of the connecting element to be pressed against the bottom surface of the second opening.

2. The method of claim 1, wherein in the step of providing the first object, the first object has a first opening, and wherein in the step of positioning the connecting element relative to the first object, positioning is achieved such that the distal portion is inserted into the first opening and the proximal portion protrudes from the first object.

3. The method according to any one of the preceding claims, wherein after the step of placing the second object relative to the first object, a gap is maintained between the first object and the second object, wherein the gap is closed as a result of the step of pressing the first object and the second object against each other when subjected to mechanical vibration energy impact.

4. The method according to claim 1 or 2, wherein after the step of placing the second object relative to the first object, a gap is maintained between the first object and the second object, wherein as a result of the step of pressing the first object and the second object against each other when subjected to mechanical vibration energy impact, the width of the gap decreases from an initial width to a final width, said final width being different from zero.

5. The method of claim 4, wherein the connecting element has a laterally projecting spacer portion, and wherein the step of pressing the first object and the second object against each other is performed until both the first object and the second object abut against the spacer portion, thereby setting the final width of the spacer portion.

6. The method of claim 4, further comprising placing adhesive between the first object and the second object, and the method further comprising allowing the adhesive to harden in a gap having a final width.

7. The method of claim 4, wherein the connecting element has a functional portion disposed in the gap.

8. The method according to claim 1 or 2, wherein the energy coupled to the first object and / or connecting element is mechanical vibration energy.

9. The method of claim 8, wherein the tool is an ultrasonic welding electrode, the extrusion surface is an external coupling surface, and wherein in the step of coupling energy to the first object and / or the connecting element, at least a portion of the mechanical vibration energy is coupled to the connecting element via the ultrasonic welding electrode.

10. The method of claim 1 or 2, wherein the adjacent surface includes the shoulder of the connecting element.

11. The method of claim 10, wherein the shoulder is an inner shoulder.

12. The method according to claim 1 or 2, wherein the connecting element comprises a proximal crown of thermoplastic material on the proximal side of the abutment surface and / or wherein the connecting element comprises a distal crown.

13. The method of claim 1 or 2, wherein the connecting element has a proximal blade-like projection terminating at a proximal edge and / or a distal blade-like projection terminating at a distal edge.

14. The method according to claim 1 or 2, wherein the connecting element is tubular and hollow.

15. The method of claim 1, wherein the connecting element has a plurality of energy-guiding ribs protruding from the outer surface.

16. The method of claim 15, wherein the energy guiding rib extends in an axial direction or spirally extends around the outer surface.

17. The method of claim 15 or 16, wherein, as a result of positioning the connecting element relative to the first object, the energy guiding rib is in physical contact with the circumferential wall of the first opening, and during the step of pressing the connecting element distally with a tool, the thermoplastic material of the connecting element also flows into the structure of the first object near the circumferential wall of the first opening.

18. The method of claim 15 or 16, wherein, as a result of placing the second object relative to the first object, the energy guiding rib is in physical contact with the circumferential wall of the second opening, and during the step of pressing the first object and the second object against each other, the thermoplastic material of the connecting element also flows into the structure of the second object near the circumferential wall of the second opening.

19. The method of claim 1 or 2, wherein the tool has a distal recess having an opening in a distal tool end face, and wherein during the step of pressing the connecting element distally using the tool, a proximal portion of the connecting element is received in the distal recess.

20. The method of claim 19, wherein the shape of the distal recess is adapted to the shape of the proximal portion of the connecting element.

21. The method of claim 1 or 2, wherein the tool has a protrusion that extends beyond at least a portion of the proximal portion of the connecting element during the step of pressing the connecting element distally using the tool.

22. The method of claim 1 or 2, further comprising the step of shaping the proximal portion of the connecting element during the step of pressing the connecting element distally by a combination of pressure and energy using a tool.

23. The method of claim 22, wherein the step of forming the proximal portion of the connecting element comprises forming the proximal portion to form at least one blade-shaped protrusion and / or a crown circumferentially surrounding the central hollow space.

24. The method of claim 23, wherein the crown forms a continuous edge at the proximal end.

25. The method of claim 23, wherein the at least one blade-shaped protrusion or crown extends discontinuously around the central hollow space and has a plurality of teeth arranged around the central hollow space.

26. The method of claim 2, wherein the first opening is a blind hole, and wherein the step of pressing the connecting element distally with a tool includes pressing the distal end of the connecting element against the bottom surface of the first opening.

27. The method of claim 2, wherein both the first opening and the second opening are blind holes, and wherein the sum of the depths of the first opening and the second opening is less than the proximal and distal lengths of the connecting element.

28. The method of claim 1 or 2, wherein after the step of pressing the connecting element to the distal side using a tool and before the step of placing the second object relative to the first object, the tool is disengaged from the connecting element, and wherein disengaging the tool is accomplished by at least one aid, such as air blowing, ejecting a plunger, or coupling vibrational energy into the tool.

29. A method for connecting a first object and a second object by means of a connecting element, the method comprising the following steps: - Provide a first object and a second object, wherein the second object has a second opening, the second opening being a blind hole; - Provide a connecting element that extends between a distal end and a proximal end and comprises a thermoplastic material; - Positioning the connecting element relative to a first object and relative to a second object, such that, according to a first selection, the distal end of the connecting element contacts the first object and, according to a second selection, the distal end of the connecting element is anchored in the first object, such that the proximal portion of the connecting element is inserted into a second opening and the proximal end of the connecting element contacts the bottom surface of the second opening, and such that a gap exists between the first object and the second object, the gap having an initial gap width. - Pressing the first and second objects together such that the proximal end of the connecting element is pressed against the bottom surface of the second opening, while simultaneously coupling mechanical vibrational energy into at least one of the first and second objects, until a portion of the thermoplastic material belonging to the proximal portion of the connecting element becomes flowable and causes it to flow into the structure of the second object to create a fixation between the connecting element and the second object after re-curing, said proximal portion including the proximal end, As a result of the step of pressing the first and second objects against each other, the first and second objects move toward each other until the gap has a smaller final gap width, which is not zero. -And wherein, according to the first option, the step of pressing the first object and the second object against each other while mechanical vibration energy is coupled to at least one of the first object and the second object causes a portion of the thermoplastic material belonging to the distal portion of the connecting element to flow and cause it to flow into the structure of the first object to create a fixation between the connecting element and the first object after re-curing, said distal portion including the distal end.

30. The method of claim 29, wherein the connecting element has a laterally projecting spacer portion, and wherein the step of pressing the first object and the second object against each other is performed until both the first object and the second object abut against the spacer portion, thereby setting the final width of the spacer portion.

31. The method of claim 29 or 30, further comprising placing adhesive between the first object and the second object, and the method further comprising allowing the adhesive to harden in a gap having a final width.

32. The method according to claim 29 or 30, wherein the connecting element has a functional portion disposed in the gap.

33. The method of claim 29 or 30, wherein in the step of providing the first object, the first object has a first opening, and wherein in the step of positioning the connecting element relative to the first object, positioning is achieved such that the distal portion is inserted into the first opening and the proximal portion protrudes from the first object.

34. The method of claim 29 or 30, wherein in the step of providing the second object, the second object has a second opening; and wherein in the step of placing the second object relative to the first object, the second object is placed such that the protruding proximal portion of the connecting element is inserted into the second opening.

35. A method for connecting a first object and a second object by means of a connecting element, the method comprising the following steps: - Provide a first object, the first object comprising a solid thermoplastic liquefiable material; - Provides a connecting element extending between a distal end and a proximal end, the connecting element including a distal portion having a distal end, the distal portion including a surface portion having an undercut coupling structure and / or deformable to include such an undercut coupling structure, whereby the distal portion can form a positive-fit connection with a first object, and the connecting element including a proximal portion comprising a thermoplastic material; - Positioning connection element relative to the first object; - Using a tool, the connecting element is pressed distally relative to the first object, while energy is coupled into the first object and / or the connecting element until the flow portion of the thermoplastic material of the first object is liquefied and flows into the coupling structure of the connecting element to create anchorage of the distal portion of the connecting element in the first object after re-curing. During the step of coupling energy into the first object and / or connecting element, the extrusion surface of the tool abuts against the adjacent surface of the connecting element, which is located on the far side of the proximal end. - Provide a second object, wherein the second object has a second opening, the second opening being a blind hole; - After a first portion of the thermoplastic material flows into the coupling structure of the connecting element, a second object is placed relative to the first object, wherein the second object is placed such that the protruding proximal portion of the connecting element is inserted into the second opening; and - Pressing the first and second objects together such that the proximal end of the connecting element is pressed against the bottom surface of the second opening, while coupling mechanical vibration energy into at least one of the first and second objects, until a second portion of the thermoplastic material belonging to the proximal portion of the connecting element becomes flowable and causes it to flow into the structure of the second object to create fixation between the connecting element and the second object after re-curing, said proximal portion including the proximal end.

36. A kit of parts for performing the method according to any one of claims 1-35, the kit of parts comprising a first ultrasonic welding electrode serving as a tool and at least one connecting element extending between a distal end and a proximal end, and comprising thermoplastic material in at least a proximal portion having a proximal end and a distal portion having a distal end, wherein the distal portion of the connecting element comprises a distal crown terminating at a distal edge, and wherein both the proximal and distal ends form at least one thermoplastic edge or tip having energy-directing properties, and the connecting element further comprises a proximal-facing abutment surface on the distal side of the proximal end, wherein the ultrasonic welding electrode extends between the proximal ultrasonic welding electrode tip and the distal ultrasonic welding electrode tip, includes a distal-facing outer coupling surface, and is adapted to contact the connecting element from the proximal side such that the outer coupling surface is in physical contact with the abutment surface for coupling mechanical vibrations into the connecting element via the outer coupling surface to liquefy the distal portion by pressing the distal portion against the bottom surface of an opening in a first object.

37. The kit of parts according to claim 36, wherein the adjacent surface is an inner shoulder.

38. A kit of parts according to any one of claims 36 or 37, wherein the connecting element has a proximal crown of thermoplastic material on the proximal side of the abutment surface.

39. The kit of parts according to claim 36 or 37, wherein the distal portion of the connecting element includes a distal crown terminating at the distal edge.

40. A kit of parts according to claim 36 or 37, wherein the ultrasonic welding electrode has a distal recess having an opening in a distal face, the distal recess being adapted to receive a proximal portion when the outer coupling surface is in physical contact with the adjacent face.

41. The kit of the parts according to claim 40, wherein the shape of the distal recess matches the shape of the proximal portion.

42. A connecting element for performing the method according to any one of claims 1-35, the connecting element extending between a distal end and a proximal end, and comprising a thermoplastic material in at least a proximal portion having a proximal end and a distal portion having a distal end, wherein the distal portion of the connecting element includes a distal crown terminating at a distal edge, wherein the distal ends each form at least one thermoplastic edge or tip having energy-directing properties, and the proximal portion is shaped as a proximal crown of thermoplastic material terminating at a proximal edge, the connecting element further having a shoulder located distal to the proximal crown, the shoulder being a proximal-facing abutment of the outer coupling surface for an ultrasonic welding electrode.

43. The connecting element of claim 42, wherein the shoulder is an inner shoulder located distal to and radially inward of the proximal coronal portion.

44. The connecting element according to claim 42 or 43 is tubular and hollow, thereby defining an internal space.

45. The connecting element of claim 44, further comprising a partition member extending laterally through the interior space.

46. ​​The connecting element according to claim 42 or 43, wherein it is made of a thermoplastic material.

47. The connecting element according to claim 42 or 43, further comprising a plurality of energy-directing ribs projecting from the outer surface.

48. The connecting element of claim 47, wherein the energy guiding rib extends in an axial direction.

49. The connecting element according to claim 42 or 43, having an outer contour that is substantially circular in a cross section perpendicular to the proximal and distal axes.

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