Abstract
A method of anchoring a lightweight building element having a first building layer and an interlining layer distally of the first building layer, and possibly a second building layer distally of the interlining layer. For anchoring, the distal end of a connector element is inserted into a mounting hole in the lightweight building element, and also a sleeve including a thermoplastic material is inserted into the mounting hole, the sleeve enclosing the connector element. Then, a distally facing liquefaction face of the sleeve is caused to be in contact with a proximally facing support face of the connector element. Energy impinges to liquefy at least a flow portion of the thermoplastic material of the sleeve, and the liquefaction face is pressed against the support face to cause at least a fraction of the flow portion to flow radially outward. After the flow portion has re-solidified, it anchors the connector element in the receiving object.
Claims
1. A connector element anchoring kit comprising a connector element configured to be anchored in a receiving object being a lightweight building element with a first building layer, and an interlining layer distally of the first building layer, wherein the first building layer is thinner and has a higher density than the interlining layer, the connector element comprising a body with a distal end for inserting into a mounting hole of the receiving object in an insertion direction along an insertion axis, the connector element comprising, distally of the proximal end, a collar extending radially, with respect to the insertion axis, from the body, the collar defining a support face, the anchoring kit further comprising a sleeve comprising a thermoplastic material in a solid state, the sleeve being configured to receive and enclose the connector element, the sleeve having a distally facing liquefaction face, wherein the sleeve near the liquefaction face has an inner cross-section which is smaller than the cross-section of the collar, wherein the connector element is insertable into the sleeve to a position in which the collar axially engages with the liquefaction face of the sleeve and the liquefaction face is in physical contact with the support face, and wherein the support face faces towards proximally and radially inwardly, whereby a groove open towards proximally and extending around the body is defined.
2. The connector element anchoring kit according to claim 1, wherein the sleeve comprises a plurality of axially separated shoulder portions configured to engage with a plurality of axially separated support faces of the connector element, to liquefy the sleeve at a plurality of axially separate melting regions.
3. The connector element anchoring kit according to claim 1, wherein the collar comprises an arrangement of tooth-like radial protrusions hat together form the collar.
4. The connector element anchoring kit according to claim 1, wherein, by the support face facing towards proximally and radially inwardly, the connector element forms an undercut with respect to radial directions, whereby, when the sleeve is pressed towards distally relative to the connector element, thermoplastic material of the sleeve may escape towards radially outwardly only when it is fully liquefied.
5. The connector element anchoring kit according to claim 1, wherein the support face together with the anchoring element body defines an overall concave surface.
6. The connector element anchoring kit according to claim 1, further comprising a sonotrode equipped to couple mechanical vibration into the sleeve for liquefying at least a flow portion of the thermoplastic material of the sleeve in contact with the support face.
7. The connector element anchoring kit according to claim 1, wherein the sleeve is configured to enclose the connector element with a radially loose fit at least at all axial positions except the distal end.
8. The connector element anchoring kit according to claim 1, wherein the connector element further comprises a distance holding portion having a height, the distance holding portion being located distally of the collar and keeping the collar at an axial distance to a structure against which the connector element abuts distally when inserted into the mounting hole.
9. A connector element anchoring kit comprising a connector element configured to be anchored in a receiving object being a lightweight building element with a first building layer, and an interlining layer distally of the first building layer, wherein the first building layer is thinner and has a higher density than the interlining layer, the connector element comprising a body with a distal end for inserting into a mounting hole of the receiving object in an insertion direction along an insertion axis, the connector element comprising, distally of the proximal end, a collar extending radially, with respect to the insertion axis, from the body, the collar defining a support face, the anchoring kit further comprising a sleeve comprising a thermoplastic material in a solid state, the sleeve having a distal end and a proximal end, and being configured to receive and enclose the connector element, the sleeve having a distally facing liquefaction face, wherein the sleeve near the liquefaction face has an inner cross-section which is smaller than the cross-section of the collar, wherein the connector element is insertable into the sleeve to a position in which the collar axially engages with the liquefaction face of the sleeve and the liquefaction face is in physical contact with the support face, and wherein the connector element further comprises a distance holding portion having a height, the distance holding portion being located distally of the collar and keeping the collar at an axial distance to a structure against which the connector element abuts distally when inserted into the mounting hole.
10. The connector element anchoring kit according to claim 9, wherein the lightweight building element has a second building layer distally of the interlining layer, wherein a height of the distance holding portion is adapted to a thickness of the interlining layer so that the support face is distally of the first building layer and, when a flow portion of thermoplastic material of the sleeve is liquefied where the sleeve contacts the support face, the flow portion flows into a region distally of the first building layer.
11. The connector element anchoring kit according to claim 9, further comprising a sonotrode equipped to couple mechanical vibration into the sleeve for liquefying at least a flow portion of the thermoplastic material of the sleeve in contact with the support face.
12. A connector element anchoring kit comprising a connector element configured to be anchored in a receiving object being a lightweight building element with a first building layer, and an interlining layer distally of the first building layer, wherein the first building layer is thinner and has a higher density than the interlining layer, the connector element comprising a body with a distal end for inserting into a mounting hole of the receiving object in an insertion direction along an insertion axis, the connector element comprising, distally of the proximal end, a collar extending radially, with respect to the insertion axis, from the body, the collar defining a support face, the anchoring kit further comprising a sleeve comprising a thermoplastic material in a solid state, the sleeve being configured to receive and enclose the connector element, the sleeve having a distally facing liquefaction face, wherein the sleeve near the liquefaction face has an inner cross-section which is smaller than the cross-section of the collar, wherein the connector element is insertable into the sleeve to a position in which the collar axially engages with the liquefaction face of the sleeve and the liquefaction face is in physical contact with the support face, wherein the sleeve comprises a plurality of thermoplastic extensions distally of the liquefaction face, wherein the collar has interruptions for the thermoplastic extensions, whereby, when the sleeve encloses the connector element and the liquefacton face is in physical contact with the support face, the extensions extend distally of the collar.
13. The connector element anchoring kit according to claim 12, further comprising a sonotrode equipped to couple mechanical vibration into the sleeve for liquefying at least a flow portion of the thermoplastic material of the sleeve in contact with the support face.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0054] The above, as well as additional objects, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, with reference to the appended drawings, where the same reference numerals are used for same or functionally equivalent elements, wherein:
[0055] FIG. 1a is a diagrammatic view in perspective of a connector element according to a first embodiment;
[0056] FIG. 1b is a perspective view of a section of the connector element of FIG. 1a, as seen along the arrows B-B of FIG. 1a;
[0057] FIG. 2a is a diagrammatic view in perspective of a sleeve according to a first embodiment;
[0058] FIG. 2b is a perspective view of a section of the sleeve of FIG. 2a, as seen along the arrows B-B of FIG. 2a;
[0059] FIG. 3 is a schematic view in section of the connector assembly including the connector of FIGS. 1a and 1b as well as the sleeve of FIGS. 2a and 2b during the anchoring process;
[0060] FIG. 4 is a schematic view in section of the connector assembly of FIG. 3 at a later stage of the anchoring process;
[0061] FIG. 5 is a schematic view in section, in part, of an alternative connector assembly at a late stage of the anchoring process;
[0062] FIG. 6 is a schematic view in section, in part, of yet another connector assembly at an early stage of the anchoring process;
[0063] FIG. 7 is a schematic view in section, in part, of an even further connector assembly at an early stage of the anchoring process;
[0064] FIG. 8 is schematic view in section, in part, of the assembly of FIG. 7 after the anchoring process;
[0065] FIG. 9 is a schematic view of a further connector element;
[0066] FIG. 10 is a detail of a sleeve and a first building layer shown in section;
[0067] FIG. 11 is a schematic illustration of an optional principle;
[0068] FIG. 12 is a schematic view in section, in part, of yet another connector assembly;
[0069] FIG. 13 is a schematic view in section, in part, of a receiving object and a connector piece with a distance holder;
[0070] FIG. 14 is a schematic view in section, in part, of a second building layer and a connector piece with a distance holder;
[0071] FIGS. 15a and 15B are schematic views in section of the distal end of a further connector piece, wherein FIG. 15b shows a section along plane B-B in FIG. 15a;
[0072] FIG. 16 is a view showing an even further connector assembly;
[0073] FIG. 17 is a schematic view in section, in part, of an alternative connector assembly at the end of the anchoring process;
[0074] FIG. 18 is a schematic view in section, in part, of an even further alternative connector assembly;
[0075] FIG. 19 is a schematic view in section, in part, of a further alternative connector assembly at the onset of the anchoring process;
[0076] FIG. 20 is a schematic view in section of an even further connector assembly, together with a sonotrode;
[0077] FIG. 21 is a schematic view of a connector element of yet another embodiment of a connector assembly;
[0078] FIG. 22 is a schematic view of a sleeve of this embodiment;
[0079] FIG. 23 is a schematic view, from a different direction, of the connector element of FIG. 21 and the sleeve of FIG. 22 in an assembled state; and
[0080] FIG. 24 is a schematic view in section of the connector assembly of FIG. 23 after the anchoring process.
DETAILED DESCRIPTION OF THE INVENTION
[0081] FIG. 1a illustrates a connector element 10 for anchoring in a receiving object, The connector element 10 has a proximal end 12 provided with a connector interface 14, which in the illustrated embodiment is configured as a female connector interface and includes an internal thread 16 for engaging with a screw (not shown) provided with a mating outer thread. The connector element 10 further has a distal end 18 for inserting into a mounting hole (not illustrated) of the receiving object. The connector element 10 has a generally circular cylindrical body 20, the circular cylindrical shape of which is coaxial with the circular cylindrical shape of the threaded female connector interface 14. At its distal end 18, the connector element 10 has a circumferential distal end collar 22 extending radially, with respect to a centre axis C1 of the circular cylindrical shape, from the body 20. The proximal face 24 of the distal end collar 22 serves as a proximally facing support face of the connector element. It slopes in the distal direction, and has a surface structure defined by a plurality of radial ridges 26. At an intermediate region between the proximal and distal ends 12, 18, the connector element 10 is provided with a circumferential, intermediate collar 28 extending radially, with respect to the centre axis C1, from the body 20. At the proximal end 12, the connector element 10 tapers to define a circumferential shoulder 30 sloping towards the distal direction.
[0082] FIG. 1b illustrates the connector element 10 in section, as indicated by arrows B-B in FIG. 1a. As can be seen in FIG. 1b, the intermediate collar 28 has a proximal face 32 sloping in the distal direction, and a distal face 34 which lies in a plane substantially perpendicular to the centre axis C1. The connector element 10 has a total length LC, which may typically be between 5 mm and 40 mm. The connector element 10 also has a diameter, which varies along the length of the connector element 10, and reaches its largest value DC at the distal end collar.
[0083] FIG. 2a illustrates a sleeve 36 made of a thermoplastic material. The sleeve 36 has a smooth, generally circular cylindrical outer face 37, and a circular cylindrical inner opening 38 configured to receive and enclose the connector element 10 in a manner that will be elucidated further below. The inner and outer circular cylindrical shapes 37, 38 of the sleeve 36 are coaxial with a centre axis C2 of the sleeve. At a distal end 40, the sleeve 36 is provided with a pair of expansion slots 42a-b extending from the distal end towards the proximal end 44 of the sleeve 36. An inner, distal edge of the sleeve 36 defines a distal liquefaction shoulder 41. At the proximal end 44, the sleeve 36 includes a rim 46 extending radially, with respect to the centre axis C2, from the sleeve 36. A proximal end liquefaction collar 47 is defined by a plurality of friction ridges 48, which extend along the direction of the centre axis C2 and are distributed about the periphery of the outer face 37. Distal ends of the friction ridges 48 define a proximal liquefaction shoulder 49 facing in the distal direction.
[0084] FIG. 2b illustrates the sleeve 36 in section, as indicated by arrows B-B in FIG. 2a. As can be seen in FIG. 2b, the proximal end 44 is provided with an inwards extending rim 50, which defines a proximal end inner shoulder 52 facing in the distal direction. At an intermediate region between the proximal and distal ends 44, 40, the sleeve 36 is provided with an inwards facing circumferential slot 54 for receiving the intermediate collar 28 of the connector element 10 (FIG. 1a). A distal edge 56 of the slot 54 slopes in the distal direction, whereas a proximal edge of the slot 54, defining an intermediate liquefaction shoulder o, is substantially parallel to a plane perpendicular to the centre axis C2. The sleeve has a total length LS, which may, by way of example, typically be between 7 mm and 60 mm.
[0085] Together with the connector element 10 of FIGS. 1a-b, the sleeve 36 defines a connector element anchoring kit. For assembling the connector anchoring kit 60 to form a connector, the proximal end 12 of the connector element 10 is pressed into the distal end 40 of the sleeve 36 along an assembly direction, During insertion, the expansion slots 42a-b permit the distal end 40 of the sleeve 36 to resiliently expand, allowing the intermediate collar 28 of the connector element 10 to be pressed into the circumferential slot 54 of the sleeve 36. Once the intermediate collar is in the circumferential slot, the distal end 40 of the sleeve 36 resiliently contracts, bringing the sleeve 36 and connector element 10 in interlocking engagement. In this configuration, the distal liquefaction shoulder 41 engages with the distal end collar 22, whereas the intermediate liquefaction shoulder 58 is axially separated from the intermediate collar 28. The engagement between the distal face 34 (FIG. 1b) of the intermediate collar 28 and the distal edge 56 (FIG. 2b) of the slot 54 maintain the sleeve 36 and connector element 10 in interlocking engagement. The sleeve 36 encloses the connector element 10 with a radially loose fit along the entire axial length. The sleeve 36 is longer than the connector element 10, and extends beyond the connector element 10 in the proximal direction.
[0086] FIGS. 3 and 4 illustrate a bonding process for anchoring the connector element 10 in the receiving object 66 being a lightweight building element.
[0087] Such lightweight building elements include two comparably thin building layers, for example of a fiber composite, such as a glass fiber composite or carbon fiber composite, a sheet metal or also, depending on the industry, of a fiberboard, and a middle layer (interlining) arranged between the building layers, for example a honeycomb structure of cardboard or other material, or a lightweight metallic foam or a polymer foam or ceramic foam, etc., or a structure of discrete distance holders. In the embodiment of FIGS. 3 and 4, the interlayer is depicted to be a foam material, whereas in other embodiments described hereinafter, the interlining layer is shown as honeycomb layer.
[0088] The lightweight building element of FIGS. 3 and 4 therefore includes a first building layer 101, a second building layer 102, and an interlining layer 103 sandwiched between the first and second building layers.
[0089] The connector including the connector element 10 and the sleeve 36 is inserted in a mounting hole 64 in the lightweight building element, which mounting hole 64 penetrates through the first building layer 101 and, in the depicted embodiment, also through the interlining layer 103. FIG. 3 shows the configuration at the onset of the anchoring process.
[0090] During anchoring, ultrasonic vibration energy is transferred to the sleeve by means of a sonotrode (not illustrated), which engages with the proximal end 44 of the sleeve 36. The sonotrode applies axial pressure in the direction of the arrow 72, and vibrates the sleeve 36 so as to generate friction heat at interfaces between the sleeve 36 and the connector element 10.
[0091] For the anchoring process, the sonotrode presses the sleeve towards distally and thereby presses the distal liquefaction shoulder 41 of the sleeve 36 against the distal end collar 22 of the connector element 10. The engagement between the distal liquefaction shoulder 41 and the proximal face 24 defines a distal liquefaction initiation interface. Friction heat generated by the sonotrode's ultrasonic vibration at the distal liquefaction initiation interface 74 liquefies the thermoplastic material of the sleeve's distal end, as illustrated in FIG. 3. As the sonotrode continues to vibrate, and push the sleeve 36 along the insertion direction, liquefied thermoplastic of the sleeve 36 is caused to flow radially outwardly and into the region of the interlining layer 103 (see arrows in FIG. 3).
[0092] The flow portion of the liquefied thermoplastic material is pressed into the material of the interlining layer adjacent to the connector element's 10 distal end. The distal end collar 22 defines a comparatively liquid-tight bottom of the liquefied thermoplastic-filled gap between the connector element 10 and the inner wall of the mounting hole 64, and thereby guides liquefied thermoplastic 76 radially outwardly and into structures of the interlayer, such as into pores of the foam. Liquefied thermoplastic also engages with the surface structure of the distal end collar 22, to later form an engagement against rotational relative movements of the sleeve and the collar once the thermoplastic subsequently cools off and solidifies.
[0093] As the sleeve 36 moves along the insertion direction, the sleeve's 36 intermediate liquefaction shoulder 58 is brought into engagement with the intermediate collar's 28 proximal face 32, so as to form an intermediate liquefaction initiation interface.
[0094] As the pressing force 72 and the mechanical vibration are kept being applied, the sonotrode presses the intermediate liquefaction shoulder 58 against the intermediate collar 28 of the connector element 10. Friction heat generated by the sonotrode's ultrasonic vibration at the intermediate liquefaction initiation interface liquefies the thermoplastic of the sleeve's 36 intermediate portion, as illustrated in FIG. 4. As the sonotrode continues to vibrate, and push the sleeve 36 along the insertion direction, liquefied thermoplastic 76 of the sleeve 36 continues to be pressed into the material of interlining layer
[0095] Depending its material composition, the mounting hole 64 may be undercut distally of the first building layer 101, i.e., the mounting hole cross section may be larger in the region of the interlining layer than where it penetrates the first building layer. By this measure, the thermoplastic material may encounter less resistance against a radial outward flow. Such undercut mounting hole may, for example, be manufactured by a drilling tool capable of oscillating about its axis. In addition or as an alternative, the undercut may be caused by the process, especially with foams of relatively low density as interlining layers, which by the hydrostatic pressure of the liquefied thermoplastic material are radially compressed. Also open porous structures with large pores may cause, by the porosity itself, allow for an underflow of the first building layer.
[0096] Once a desired position has been reached the pressure and vibration ceases, e.g., by de-energizing the sonotrode or disengaging it from the sleeve 36, and the thermoplastic 76 is allowed to re-solidify. The top of the sleeve 36 remains intact throughout the anchoring process and, in the final position extends beyond the connector element 10 in the direction opposite to the insertion direction. In the illustrated example, the connector element 10 has an axial length LC (FIG. 1b) shorter than and axial depth of the mounting hole 64, such that it will be slightly countersunk into the mounting hole 64 when in the final position. Thereby, accidental contact between the sonotrode and the connector element 10 may be avoided, since the surface of the receiving object 66 may act as an end stop for the sonotrode. During bonding, the proximal end inner shoulder 52 (FIG. 2b) of the sleeve 36 may have been liquefied by the friction engagement with the circumferential shoulder 30 (FIG. 1a) of the connector element 10 to tightly embed the shoulder 30; alternatively, the anchoring process may be halted before the proximal end inner shoulder 52 reaches the circumferential shoulder 30 of the connector element 10.
[0097] In the final position, the sleeve 36 may protrude above the surface of the receiving object 66. In a slight variation, the process may instead continue until the proximal end 44 of the sleeve 36 reaches a position where it is flush with the surface of the receiving object 66. In another variation, the third bonding step may continue until the proximal end 44 of the sleeve 36 reaches a position where it is countersunk into the receiving object 66.
[0098] Given the configuration shown in FIGS. 3 and 4, the anchoring strength achievable, especially against pull-out forces, may, depending on the interlining material, be only moderate, since the dimensional stability of the interlining material itself may be limited. In situations where this is not acceptable, measures discussed hereinafter may be taken. For example, the illustrated second (intermediate) liquefaction interface may be more proximally than shown in FIGS. 3 and 4, or a third liquefaction interface arranged more proximally than the second liquefaction interface may be present, so that at least a part of the flow portion flows into the space immediately distally of the first building layer.
[0099] Also, the expansion slots 42a, 42b may be omitted to prevent the thermoplastic material of the sleeve from being pushed towards radially outwardly prior to its liquefaction.
[0100] FIG. 5 illustrates the principle of anchoring in a region immediately distally of the first building layer, in a sub-building-layer region 111. The flow portion 76 of the thermoplastic material according to this principle fills a space between the proximally facing support face 24 and first building layer (or, to be precise, it's distally facing surface) adjacent the mouth of the mounting hole formed in the first building layer. Thereby, the flow portion 76 together with the connector element 10 forms a kind of rivet and is secured against pulling movements out of the receiving object by the strength and dimensional stability of the first building layer.
[0101] In FIGS. 1a and 1b the proximally facing support face 24 is shown to be sloping away from the body 20 of the connector element 10, i.e., the support face 24 faces towards proximally and radially outwardly. Such configuration is especially advantageous in situations where material around the mounting hole has a high dimensional stability thereby guiding the sleeve and counteracting any outward movement and flow of portions of the sleeve and liquefied thermoplastic material thereof, respectively. The tapering shape of the support face therein assists the desired radial outward flow.
[0102] However, in situations in which the material around the mounting hole is comparably weaker, which will often be the case for interlining layers, then a substantial slope away from the axis may counteract the desire to cause the thermoplastic material to flow to immediately distally of the first building layer 101. To this end, the support face 24 in the example of FIG. 5 is illustrated to be almost perpendicular to the axis, sloping away from the axis only slightly.
[0103] In other embodiments, especially if the sleeve is comparably thin and/or if the interlining material is removed around the mounting hole and/or offers little resistance, then it may even be desirable to configure the connector element to include a catch preventing the sleeve from being deformed towards radially outwardly and radially confining the non-liquefied portions of the sleeve. Such a configuration is illustrated in FIG. 6. The proximally facing support face 24 faces towards proximally and radially inwardly, whereby the connector element forms an undercut with respect to radial directions and the support face 24 together with the anchoring element body 20 defines an overall concave surface. By this, any sliding outwardly of softened but not yet flowable portions of the sleeve is prevented. The thermoplastic material may escape towards radially outwardly only when it is fully liquefied.
[0104] FIG. 7 shows a variant with a first proximally facing support face 24, the first proximal support face forming an undercut with respect to radial directions and thereby serving as a catch of the kind described with respect to FIG. 6. A second proximally facing support face 25 may, but does not need to, be undercut with respect to radial directions also. It cooperates with a liquefaction shoulder 58 of the kind described hereinbefore to liquefy portions of the thermoplastic material after some first portions have been liquefied in contact with the first proximally facing support face 24 and the sleeve has been correspondingly shortened in the process. FIG. 8 shows the result with the flow portion 76 having two main contributions 77, 79 from the first and second liquefaction interface, respectively. Also in this embodiment, the flow portion fills a space between at least one of its proximally facing support faces and the first building layer 101.
[0105] FIG. 9 shows a variant in which the first proximally facing support face 24 again defines an undercut with respect to radial directions (namely, a circumferential groove open towards proximally). In contrast to the embodiment of FIGS. 7 and 8, the second proximally facing support face 25, however, is distributed by belonging to a plurality of radial protrusions 121 distributed around the periphery of the anchoring element body 20 at equal or different axial positions. The radial protrusions 121 in addition to serving to define the second support face 25 also may serve to stabilize the connector element against the sleeve after anchoring, as described in more detail hereinafter referring to FIG. 12.
[0106] FIG. 10 depicts a detail which may be optional for any embodiment of the invention. Namely, the sleeve has a flange portion 131 which secures it against radial inward movements at the end of the anchoring process and thereafter. The first building layer 101 may optionally have a shallow indentation 132 along the mounting hole to receive the flange portion in case it is desired that the connector, or at least the sleeve thereof, is essentially flush with the outer surface of the receiving object at the end of the process.
[0107] FIG. 11 firstly depicts a principle that is applicable to receiving objects having a first building layer 101 that has substantial resilience. In the anchoring process, the first building layer may be deformed to be deflected inwardly by a corresponding feature—for example the distal end faces of ridges 48 of the kind shown in FIGS. 2a/2b—of the sleeve. Then, due to the rising resilient force and/or a declining resistance of the sleeve material that softens and becomes flowable where friction with the receiving object arises, the first building layer flexes back to its original position, as illustrated by an arrow in FIG. 11.
[0108] Secondly, FIG. 11 shows a receiving volume 141 of the connector for the first building layer 101. Such receiving volume may have an axial undercut, as shown in FIG. 11. If the first building layer along the rim of the mounting hole is accommodated in such receiving volume, this gives additional stability for the anchoring. Such receiving volume is an option also for embodiments in which the first building layer is not flexible. Then, the sleeve material distally of the receiving volume is made flowable in the process of inserting the sleeve to stabilize, after re-solidification, the sleeve against the first building layer.
[0109] FIG. 12 shows the principle of the connector element 10 having indentations 151 and/or protrusions 152 for cooperating with sleeve material to give an additional axial and/or rotational stability. In this, indentations 151 may be filled during the process by liquefied thermoplastic material of the sleeve to yield the desired positive-fit connection after the process. Alternatively, the sleeve 36 may be provided with pre-shaped protrusions for cooperating with the indentations, and may be configured to be slightly flexible for insertion. Concerning the protrusions 152, the sleeve may include pre-shaped indentations 153, or alternatively such indentations may form in the course of the process by thermoplastic material being liquefied.
[0110] Many lightweight building elements have a thickness of the interlining layer 103 that is too large for an only proximally facing support face 24 to be arranged at a collar 22 if the collar is at the distal end, if the connector element 10 is inserted into the mounting hole as far as to abut against the second building layer 102, and if the thermoplastic material is to flow into the sub-building-layer region 111. Therefore, the anchoring method in embodiments may include holding the connector element in a position in which it does not reach the second building layer. A possible disadvantage of this may be that, depending on machinery and interlining material, the position may be not as well defined as a position in which the connector abuts the second building layer as shown in FIGS. 3 and 4, for example.
[0111] FIG. 13 illustrates an embodiments in which the connector includes, distally of the collar 22 that defines the support face 24, a distance holding portion 161. The height h of such distance holding portion may be adapted to the thickness of the interlining layer 103 so that the flow portion flows into the sub-building-layer region 111 when the connector element 10 is in a position in which the distance holding portion 161 abuts the second building layer or another defined structure in the receiving object.
[0112] FIG. 14 shows a variant in which the distance holding portion is formed by a reinforcement 171 between the distal end of the connector element and the second building layer 101.
[0113] In the embodiment of FIGS. 15a and 15b, the distance holding portion is formed by a structure including a central element 181 and self-reaming wings 182 shaped to be advanced in to the interlining material even if the mounting hole is not as deep as to reach the second building layer. More generally, the distal end of the connector element 10 may be provided with any suitable drilling or reaming structure. For inserting the connector element, the connector element may be subject to mechanical movements adapted to such drilling or reaming structure, for example to rotational or vibrational movement.
[0114] The embodiment of FIG. 16 realizes yet another optional principle. Namely, the sleeve is provided with a plurality of thermoplastic extensions 191 configured to reach beyond the connector element 10. To this end, the collar 22 of the connector element has an according number of interruptions 192 through which the extensions 191 may be slid. In the process, when the sleeve 36 is pressed towards distally with mechanical vibrations impinging on it, the distal ends of the extensions are pressed against structures of the receiving object, for example the proximally facing surface of the second building layer 102. This results in a liquefaction of the distal ends of the extensions and interpenetration of structures of the receiving object. Once as the distal liquefaction shoulder 41 is in contact with the support face, additional liquefaction will take place at this liquefaction interface, in accordance with the principle described hereinbefore. The liquefied and re-solidified thermoplastic material from the distal end of the extensions 191, by the interpenetration of structures of the receiving object, contributes to the anchoring of the connector.
[0115] FIG. 17 shows an alternative embodiment of a connector element structure with a proximally facing support face that defines an undercut with respect to radial directions. In contrast to the embodiments of, for example, FIGS. 7, 9 and 13 the face does not have a conical shape but is concave in axial section. Other shapes are possible. FIG. 18 shows a structure in which the proximally facing abutment surface has a stepped shape in which a groove with a rectangular cross section ensures the positive fit with respect to radial direction and thereby defines the catch.
[0116] In the previously described embodiments, the connector element was illustrated as belonging to a connector that serves as an anchor in the receiving for a further object to be fastened thereto. To this end, the connector element in FIGS. 1a and 1b has the connector interface 14. However, the connector does not need to include such connector interface 14. Rather, the connector may in some embodiments itself serve as the object to be anchored relative to the receiving object, for example by having a functional structure. In addition or as an alternative, the connector element and/or the sleeve may have incorporated the element to be anchored relative to the receiving object, for example in the form of a sensor or actuator. As an even further alternative, the connector may serve as rivet securing a further object 195 to the receiving object, as illustrated in FIG. 19. Therein, the sleeve has a flange 131 or head feature and the connector element 10 has a flange 191 or foot feature, whereby the receiving object (lightweight building element) and the further object 195 are clamped against each other at the end of the process, between the respective flange (head, foot) features.
[0117] FIG. 20 shows the principle that a connector interface of the connector element 10 does not necessarily have to be a female connector interface. Rather, in the embodiment of FIG. 20, the connector element is illustrated to have a male connector interface 114, namely a threaded bar extending proximally. Alternatively, a male connector interface may include a spherical head or any other suitable structure. In embodiments with a male connector interface 114, the optional condition that the sleeve 36 is longer than the connector element—or than the portion of the connector element proximally of a distance holding portion 161—a may be replaced by a condition that the sleeve is longer than an axial width b of a bonding zone. Such bonding zone extends between the proximally facing support face 24 and an axial position—illustrated by a dashed line in FIG. 20—that corresponds to the level of the receiving object first building layer when the connector is inserted. A sonotrode 160 for coupling the mechanical vibration into the sleeve 36 (partially illustrated in FIG. 20) in such embodiments is adapted such as to not come into contact with the male connector interface 114, for example by being hollow.
[0118] In the embodiment of FIGS. 21 and 22, the connector element has a distal end collar that is distinct from the end collar 22 of the embodiment of for example FIGS. 1a-2b at least by having the following properties: [0119] Firstly, the distal end collar 22 is not uninterrupted but includes an arrangement of tooth-like radial protrusions 202 that together form the collar. Thus, compared to an uninterrupted collar, the area of the liquefaction interface is reduced. Also, the tooth shape of the protrusions provides for an additional energy directing effect. As a result of both these effects, an overall resistance against the forward movement of the sleeve relative to the collar during the process is reduced so that compared to the previously described embodiments, the approach is useable for example for thermoplastic material that are harder and/or have a higher glass transition temperature. Further, thermoplastic material may—and will—be conveyed forwardly towards distally during the process in the spaces between the protrusions, and will flow past the distal end of the connector element to achieve additional anchoring. [0120] Secondly, the distal end collar has a radial extension that is smaller than the radial extension of the sleeve at the liquefaction interface, see FIG. 23 showing the sleeve of FIG. 22 and the connector element of FIG. 21 in an assembled state and in upside-down orientation compared to FIGS. 21 and 22. Also this property (smaller radial extension of the distal end collar) has the effects of reducing the overall resistance by a reduced interface area and an energy directing effect, especially of radially-outer edges, and of allowing a material transport past the collar.
[0121] These first and second properties are independent of each other, i.e., they may be realized in combination, as illustrated, or individually.
[0122] FIG. 24 illustrates, in section, the assembly after the process, the section plane being chosen so that on the left-hand side it extends through one of the protrusions 202 whereas on the right-hand side it extends through a space between the protrusions. The flow portion 76 of the thermoplastic material includes a portion that has flown distally of the distal end of the connector and for example interpenetrates structures of the second building layer 102. Also a weld to thermoplastic material of the second building layer 102, if the second building layer 102 has thermoplastic material, for example a thermoplastic matrix material, is possible.
[0123] Generally, the features of the different embodiments may be combined. For example, different shapes of the support face may be combined with different distal (distance holding or other) structures, and both may be realized in configurations with one or more support faces of the connector.
[0124] A machine configured for carrying out the process described above may include a positioning device configured to place the connector element 10 and sleeve 36 in a mounting hole 64 of a receiving object 66. It may also include an energy transfer device, such as a heater or sonotrode, for transferring energy to the sleeve 36. The machine may also be equipped with a magazine including a plurality of sleeves 36 and connector elements 10, either as separate components or as connector assemblies 62, for automated, repeated anchoring operations on a feed of receiving objects moving through the machine.
[0125] The connector element 10 is made of a relatively non-thermoplastic material. An exemplary, suitable material for the connector element is metal, such as steel, aluminium, zinc alloy such as Zamak 5, or pot metal. However, the term relatively non-thermoplastic should be construed in the context of the anchoring process; in order to anchor a connector element 10 using the process, the body 20 of the connector element 10 needs to remain solid throughout the anchoring process. Hence, the term “relatively non-thermoplastic” should be construed to include also any thermoplastic materials having a melting point substantially higher than that of the sleeve 36, for example by at least 50° C., since such materials will not have thermoplastic properties in the context of the invention.
[0126] A thermoplastic material suitable for the sleeve 36 described hereinabove may include a polymeric phase (especially C, P, S or Si chain based) that transforms from solid into liquid or flowable above a critical temperature range, for example by melting, and retransforms into a solid material when again cooled below the critical temperature range, for example by crystallization, whereby the viscosity of the solid phase is several orders of magnitude, such as at least three orders of magnitude, higher than that of the liquid phase. The thermoplastic material may generally include a polymeric component that is not cross-linked covalently or that is cross-linked in a manner that the cross-linking bonds open reversibly upon heating to or above a melting temperature range. The polymer material may further include a filler, e.g., fibres or particles of a material that has no thermoplastic properties or has thermoplastic properties including a melting temperature range that is considerably higher than the melting temperature range of the basic polymer. Examples for the thermoplastic material are thermoplastic polymers, co-polymers or filled polymers, wherein the basic polymer or co-polymer is, e.g., polyethylene, polypropylene, polyamides (in particular polyamide 12, polyamide 11, polyamide 6, or polyamide 66), polyoxymethylene, polycarbonate-urethane, polycarbonates or polyester carbonates, acrylonitrile butadiene styrene (ABS), acrylonitrile-styrene-acrylate (ASA), styrene-acrylonitrile, polyvinyl chloride, polystyrene, or polyether ether ketone (PEEK), polyetherimide (PEI), polysulfone (PSU), poly(p-phenylene sulphide) (PPS), liquid crystal polymers (LCP), etc.
[0127] Mechanical vibration or oscillation suitable for the method according to the invention may typically have a frequency between 2 and 200 kHz; more typically between 10 and 100 kHz; and even more typically between 15 and 40 kHz. It may, by way of example, provide a typical vibration power of 0.2 to 20 W per square millimetre of active surface. The vibrating tool (e.g. sonotrode) may be designed such that its interface with the sleeve oscillates predominantly in the direction of the insertion axis and with an amplitude of between 1 and 100 μm, such as around 30 to 60 μm.
[0128] The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention as defined by the appended patent claims. For example, the mounting hole 64 (FIG. 3) is illustrated as a blind hole. However, it may alternatively be configured as a through-hole, extending all the way through the lightweight building element. The inner face of the through-hole may be provided with an end-stop shoulder, for example by forming a smaller-diameter through-hole 64a through second building element 102. Thereby, the inner thread 14 (FIG. 1a) of the connector element 10 may be accessed from either side of the board. Moreover, the sleeve 36 (FIG. 2a) has been illustrated as having an axial through-hole 38 for receiving the connector element 10. However, this is not necessary—it may suffice that the sleeve is open at only one end. By way of example, the sleeve 36 may be closed by an axial end wall at the proximal end. Such a sleeve may be used for anchoring a hidden connector element that may be later accessed, by, e.g., removing the axial end wall to expose the thread, for installing optional components of, e.g., a re-configurable furniture system. In the foregoing, all components have been illustrated to have a substantially circular cylindrical or rotation-symmetric geometry about the insertion axis and centre axes C1, C2 (FIGS. 1a, 2a). However, even though such geometry may be preferred for circular mounting holes 64, and circular mounting holes may be easier to form by, e.g., drilling, a circular geometry is not necessary. Moreover, the connector element, the sleeve and the mounting hole do not need to have the same general shape, or mating shapes. In the foregoing, the first and second connector interfaces are described as screw interfaces. However, this is not necessary. The invention is also suitable for anchoring other types of connector interfaces, such as bayonet interfaces, click connections, magnets, clips, etc. The connector element to be anchored in the receiving object need not be provided with a female connector interface; alternatively, it may be a male connector interface, such as a threaded pin.
[0129] Embodiments that include transferring the energy as mechanical rotation energy will use connector elements and sleeves that compared to the connector elements/sleeves shown in the depicted embodiments include modifications. For example, the connector element of FIGS. 1a and 1b will not include the ridges 26 but an essentially rotationally symmetrical end collar 22. Similarly, the sleeve 36 of FIGS. 2a and 2b will not have the energy directing ridges 48 but a for example smooth or roughened outer surface. Further, both, the connector element and the sleeve will have torque transferring engagement structures. For example for the connector element, such engagement structures may be structures replacing the shown connector interface 14 or may be provided in addition thereto. For the sleeve, such engagement structures may for example be present as shape of a proximal portion of an inner surface around the axial through hole 38.
