EXPANSION ANCHOR AND FIXING SYSTEM

Abstract

The invention relates to an expansion anchor (1) made of plastic, comprising at least two expansion elements (15) in an expansion zone (11), which can be expanded by inserting a screw (3) into an expansion channel (9) of the expansion anchor (1). The expansion channel (9) extends concentrically along a central longitudinal axis (L) of the expansion anchor (1). The expansion elements (15) are separated from each other by a groove (21) that defines a median plane between the expansion elements (15) where the longitudinal axis (L) is located. Furthermore, the expansion elements (15) are integrally connected to each other by at least one net-shaped connector (22) disposed in the groove (21) between the two expansion elements (15).The connector (22) has at least a first portion (23) inclined at a first acute angle (α1) with respect to the central longitudinal axis (L), such that the central longitudinal axis (L) intersects the first section (23) of the connector (22) at at least one point.

Description

DESCRIPTIVE MEMORANDUM The invention relates to an expansion anchor made of plastic having the characteristics of the generic term of claim 1, and to a fastening system comprising an expansion anchor according to the generic term of claim 12. These expansion anchors are typically used to secure components to an anchoring surface, such as a concrete or masonry wall. The expansion anchor is inserted into a pre-drilled hole in the anchoring surface, and an expansion section of the anchor is then expanded by means of an expansion element, such as a nail or screw. This expansion element is inserted into an expansion channel of the anchor. For example, the anchor is expanded by driving a screw or nail into it, which presses the expansion elements of the anchor against the wall of the pre-drilled hole, thus securing the anchor in place. Based on US patent application 2021 / 0079941 A1, a generic expansion anchor is known, comprising an expansion zone with two expansion elements that can be expanded by inserting an expansion body into an expansion channel of the expansion anchor. At a forward end in the insertion direction, the two expansion elements are integrally connected to each other by a web-like connector. This connector prevents the two expansion elements from expanding outward due to friction against the wall of the drilled hole during insertion, thus complicating or preventing the insertion of the expansion anchor into the drilled hole.When the expansion body is inserted into the expansion channel, the two expansion elements are pushed radially outward and away from each other relative to the longitudinal axis of the expansion anchor, causing tensile loading of the connector until it fails. Because the connector is made of plastic and can therefore absorb relatively large tensile forces, relatively high expansion forces are required for expansion compared to expansion anchors without connectors. These, in turn, require relatively large axial forces to drive a nail or relatively high torque to tighten a screw, making the expansion anchor less practical. 2195385 of 11 Therefore, the objective of the invention is to create an expansion anchor whose ease of installation is improved. This task is solved according to the invention by means of an expansion anchor with the characteristics of claim 1 and a fixing system with said expansion anchor according to claim 12. The expansion anchor according to the invention is made of plastic, wherein the expansion anchor may consist of a single plastic component, i.e., a plastic such as polyamide, or of several plastic components, such as polyamide and polypropylene. This does not preclude the expansion anchor from comprising elements that are not made of plastic, such as metal. In particular, the expansion anchor is an injection-molded part, produced by single-component or multi-component injection molding, and may have, for example, an injection-molded or die-cast insert. The expansion anchor has an expansion zone with at least two expansion elements separated by a groove. The expansion zone may have different cross-sections, and its design, or that of the expansion elements, may vary longitudinally and / or circumferentially. Within the expansion zone is an expansion channel extending concentrically to and along a central longitudinal axis of the expansion anchor. This central longitudinal axis runs parallel to an insertion direction in which the expansion anchor is inserted into a pre-drilled hole. It is concentric with the circles inscribed in the expansion channel and defines the axial or longitudinal direction of the expansion anchor.In particular, the expansion elements enclose the expansion channel at least partially, and in particular substantially completely, except for one or more slots between the expansion elements. The expansion elements are separated from each other by a slot that defines a median plane between the expansion elements where the longitudinal axis lies. The slot may penetrate completely into the expansion zone or only extend radially from the outside, i.e., from the outer circumference of the expansion anchor, into the expansion channel. By inserting an expansion body into the expansion channel, the two expansion elements can expand, i.e., they are moved away from each other by the expansion body and, with respect to the central longitudinal axis, radially towards 2 2195385 of 11 outside. To prevent unintentional extension, the two expansion elements are joined together by at least one web connector, specifically in a section of the expansion pin that is forward in the insertion direction. The web connector is arranged in the groove between the two expansion elements. It is therefore completely intersected by the median plane. The front section in the insertion direction is the section of the expansion anchor with which the expansion anchor is inserted frontally when it is inserted into a hole drilled along the plane. The term "web connector" here means that the connector is elongated, i.e., in relation to a Cartesian coordinate system, in one direction many times greater than in the other directions.In particular, the connector is many times larger along the central longitudinal axis than radially to the central longitudinal axis. Specifically, the net-type connector has a substantially rectangular cross-section. The connector may be straight, curved, or corrugated. According to the invention, the connector comprises at least one portion, hereinafter referred to as the first portion, which is inclined at an acute angle, hereinafter referred to as the first acute angle, with respect to the central longitudinal axis. The first portion is inclined at the first acute angle with respect to the central longitudinal axis such that the central longitudinal axis intersects this portion at at least one point, in particular completely, thereby penetrating the connector. The first acute angle lies in the median plane; that is, the longitudinal axis and a straight line enclosing the first acute angle with the longitudinal axis lie in the median plane. The designation "first section" or "first acute angle" does not imply that there must be a second section or a second acute angle. Thus, although the section of the connector is hereafter referred to as the "first section," it is not required for the invention that the connector have a second section or more sections. An acute angle is understood to be an angle between 0° and 90°, in particular an angle between 5° and 60°. The design of the expansion anchor according to the invention has the advantage that the connector is not only subjected to tensile stress during expansion. In addition to tensile stress, the expansion body cuts the connector, weakening it. Specifically, the cutting occurs not only selectively at the tip of the spacer body but also, due to the connector's acute angle relative to the axis, at an acute angle to the axis. 2195385 of 11 longitudinal center, the separator body cuts the connector longitudinally in part, in particular over 50% of the connector's length, in particular over a large part of its length, i.e., over 75% of its length, in particular completely. If the expander is a screw with external threads, the flanks of the thread may cut the connector in addition to or as an alternative to the tip and further weaken or destroy the connector. Preferably, the connector has a second section inclined at a second acute angle with respect to the central longitudinal axis. In particular, the first and second sections are arranged one behind the other in the axial direction. They may be joined together or offset from each other, and thus inclined in the same direction, particularly parallel to each other, i.e., at the same angle with respect to the central longitudinal axis. Preferably, the second acute angle is inclined opposite to the first acute angle with respect to the central longitudinal axis. The second acute angle is also stretched in the midplane. By means of these embodiments, the radial expansion of the connector can be limited so that as much of the connector as possible is gripped, torn, sheared, or at least sheared, torn, and weakened by the expansion body when it is inserted into the expansion anchor.In this case, the two sections in particular merge into one another; that is, they are not axially separated from each other, but rather connected. Specifically, the two sections form a single piece. There can also be more than two sections, in which case, specifically, two adjacent sections are inclined in directions opposite to the longitudinal axis. Furthermore, it is preferred that the first acute angle and / or the second acute angle be less than 45°, and in particular, less than 30°. This ensures that the screw tip and / or thread will split, tear, and / or cut the sections longitudinally over a greater distance. Specifically, the first and second acute angles are equal. In a preferred embodiment of the expansion anchor according to the invention, the expansion channel does not fully penetrate the expansion anchor in the direction of the central longitudinal axis. Specifically, the expansion channel is closed at its front end. Preferably, the connector is arranged in front of the expansion channel in the direction of the central longitudinal axis in the insertion direction and, preferably, closes the expansion channel forward. 2195385 of 11 Furthermore, it is preferred that the extension of the first section of the connector along the central longitudinal axis be at least five times greater than its extension perpendicular to the central longitudinal axis. Thus, the length of the section measured along the central longitudinal axis is greater than the width and height of the section measured radially to the central longitudinal axis. This also means that the primary direction of extension of the first section is longitudinal, ensuring that a bolt inserted into the expansion anchor can contact the section over as large an area as possible, cutting, tearing, and / or opening it. In particular, the second section, if present, also has an extension along the central longitudinal axis that is at least five times greater than its extension perpendicular to the central longitudinal axis. Specifically, the extensions of the two sections are equal. Preferably, the entire connector is positioned within a radially interior region of the expansion anchor, particularly centrally. This means that the connector does not extend radially outwards. This ensures that at least a significant portion of the connector, in particular the entire connector, makes contact with the expansion body. Preferably, at least part of the connector, in particular an entire section, or, if the connector comprises several sections, several, or in particular all sections, are injection-molded skins. "Injection-molded skin" here refers to a thin-walled connector with a wall thickness of less than 0.5 millimeters. The expansion anchor according to the invention forms a fastening system with an expansion body having a point. An expansion body is, for example, a nail, in particular a screw, such as a wood or chipboard screw with a threaded flank. This expansion body is inserted flat, point first, into the expansion channel along the longitudinal axis of the expansion anchor, i.e., in the insertion direction, for the flat expansion of the expansion zone of the expansion anchor.According to the invention, the expansion channel is designed such that the tip of the expansion body is arranged on the central longitudinal axis during insertion, so that it is ensured that the expansion body meets the connector, grips it, and, during subsequent insertion of the expansion body, the connector tears open and is therefore destroyed or at least cut, torn and weakened by the expansion body. 2195385 of 11 expansion, in particular by its tip and / or, where applicable, by the thread flanks, so that the expansion anchor can be easily expanded. Preferably, the connector and expansion channel are arranged so that the tip of the expansion body does not contact the connector during insertion until the expansion body completely fills the expansion channel along the central longitudinal axis. This provides the expansion body with sufficient grip in the expansion channel and, in the case of a screw as the expansion body, ensures sufficient drive to penetrate the connector or to weaken or completely destroy it. The features and combinations of features, embodiments, and executions of the invention mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or drawn in a figure, may be used not only in the combination indicated or drawn in each case, but also in virtually any other combination or individually. Embodiments of the invention that do not have all the features of a dependent claim are possible. Individual features of a claim may also be substituted by other disclosed features or combinations of features. The invention is explained in more detail below by reference to an example of an embodiment. In them: Figure 1 shows a perspective view of an expansion anchor according to the invention; Figure 2 shows an axial section of the expansion anchor according to the invention without an expansion body; and Figure 3 shows the axial section of Figure 2 with a screw inserted into the expansion channel as the expansion body. Figures 1 to 3 show an expansion anchor 1 according to the invention which, together with the expansion body 2 shown in Figure 3, in the embodiment, a screw 3, forms a fixing system according to the invention. 2195385 of 11 The expansion anchor 1 extends along a central longitudinal axis L from a rear end 4, where a circumferential collar 5 is arranged, axially to a front end 6 in an insertion direction E, a flattened tip of the expansion anchor 1, with which the expansion anchor 1 is inserted frontally into a drilled hole (not shown) during planned insertion. A sleeve-shaped retention zone 7 abuts the collar 5 anteriorly. Two radially projecting retention arms 8 are arranged at opposite points in this zone. These arms secure the expansion anchor 1 after its insertion into the drilled hole and the screw 3 after its insertion into the retention zone 7 and before the screw 3 is subsequently tightened into the expansion channel 9. The two retention arms 8 are partially rotated inwards into an expansion channel 9 of the expansion anchor 1 after its insertion into the drilled hole. The expansion channel 9 runs concentrically along the central longitudinal axis L of the expansion anchor 1. Adjacent to the retention zone 7 forward is an expansion zone 11, which extends to the front end 6 of the expansion anchor 1 and encompasses the front end 6. The expansion zone 11 consists of three parts: a rear part 12 adjacent to the retention zone 7, a front part 14 with the front end 6, and an intermediate part 13 between the two. The rear portion 12 of the expansion zone 11 comprises two expansion elements 15, which have ribs 16 on their outer surface and extend to the front end 6 of the expansion anchor 1. The expansion elements 15 are thus also components of the central portion 13 and the front portion 14. In the circumferential direction between the two expansion elements 15, there are two expansion legs 17 arranged at the rear portion 12, which are circumferentially separated from the expansion elements 15 by two rear longitudinal grooves 18 each. The expansion legs 17 and the expansion elements 15 each have a radial thickness, relative to the central longitudinal axis L, which is greater than the radial thickness of the wall of the sleeve-type retention zone 7, as shown in Figure 2, and therefore narrow the expansion channel 9.The two expansion elements 15 together with the expansion legs 17 enclose the expansion channel 9 so that a screw 3 is guided when inserted into the expansion channel 9. 2195385 of 11 In the central part 13 of the expansion zone 11, the two expansion elements 15 are connected circumferentially by V-shaped connecting bands 19. Between the connecting bands 19, longitudinally, are openings 20, completely enclosed by thin plastic walls. In this central part 13, the expansion channel 9 has the same inner diameter as in the rear part 12 of the expansion zone 11. In the front portion 14 of the expansion zone 11, the two thicker-walled expansion elements 15 are semicylindrical in design and are separated only by a continuous groove 21 that runs flat in an axial plane to the central longitudinal axis L and has a width of 0.5 millimeters. The groove 21 defines a median plane in which the longitudinal axis L lies. The median plane corresponds to the drawing plane in Figures 2 and 3. A thin-walled, injection-molded skin, less than 0.5 millimeters thick, is arranged in the groove 21 as an elongated, net-like connector 22. This connector extends along almost the entire length of the front portion 14, approximately 16 millimeters wide, and integrally connects the two expansion elements 15 to each other. As can be seen in Figures 2 and 3, the connector 22 is centrally located in the expansion anchor 1, i.e., in a radially interior region of the expansion anchor 1.Connector 22 has two sections 23, 24 arranged one behind the other in a longitudinal direction, both inclined with respect to the central longitudinal axis L by two acute angles 1, 2 of approximately 10°, but opposite each other. Both sections 23, 24 of connector 22 are centrally arranged such that the central longitudinal axis L intersects both at at least one point due to their inclination by the two acute angles 1, 2, as can be seen in Figures 2 and 3. The first section 23 and the second section 24, which is arranged in front of it in the insertion direction E and extends to the front end 6 of the expansion anchor 1, are integrally fused together. The axial length of the first section 23 of connector 22 is approximately 12 millimeters, and that of the second section 24 is approximately 4 millimeters. The expansion channel 9 does not fully penetrate the expansion anchor 1 in the direction of the central longitudinal axis L, but terminates at the front part 14 of the expansion zone 11 at a distance from the front end 6, i.e., where the connector 22 begins. The connector 22 is arranged in front of the expansion channel 9 in the direction of the central longitudinal axis L in the insertion direction (E) and closes it forward by means of a radial extension 25. 2195385 of 11 The entire expansion anchor 1 is manufactured in a single piece of polyamide using injection molding. When screw 3 is inserted into the expansion anchor 1, screw 3, like the expansion body 2, expands the expansion anchor 1 radially, as shown in Figure 3. In Figure 3, screw 3 is fully threaded into the expansion channel 9, so that screw 3 completely fills the expansion channel 9 in the direction of the central longitudinal axis L. The tip 10 of screw 3 is located at the end of the expansion channel 9. The tip 10 of screw 3 rests against the rear end of the connector 22, i.e., against the radial extension 25.Due to the design of the expansion channel 9, the tip 10 of the screw 3 or the expansion body 2 is positioned on the central longitudinal axis L when inserted, so that when the screw 3 is screwed in further, the tip 10 first penetrates the radial extension 25, then the first section 23 and then the second section 24 of the connector 22 are axially opened and torn apart, destroying the entire connector 22, whose radial extension is less than the diameter of the screw 3, so that the connector 22 can no longer perform its function of connecting the two expansion elements 15. Once the expansion anchor 1 has been inserted into the drilled hole as intended, this function is also no longer required.Conversely, here the connector 22 would hinder the expansion of at least the front part 14 of the expansion zone, so destroying the connector 22 when screwing in the screw 3 is advantageous, since it facilitates expansion and reduces the torque required to screw in the screw 3, thus improving the ease of installation of the expansion anchor 1 according to the invention. 2195385 of 11 reference symbols Expansion anchor Expansion body Screw Rear end of expansion anchor 1 Collar Front end of expansion anchor 1 Retention zone Support arm Expansion channel Screw tip 3 or expansion body 2 Expansion zone Rear of expansion zone 11 Central part of expansion zone 11 Front of expansion zone 11 Expansion element Rib Expansion leg Rear longitudinal slot Connection band Orifice Slot Connector First section of connector 22 Second section of connector 22 Radial extension of connector 22 First acute angle Second acute angle Insertion address Central longitudinal axis 2195385 of 11 MOELLER & CO. SA - 30529767664 Digitally signed by PORTALTRAMITES - INPI Date: 2023.03.15 09:20:24 -03:00 Reason: Digitally Signed by the INPI Location: Buenos Aires, Argentina 2195385

Claims

1. A plastic expansion anchor (1) comprising, in an expansion zone (11), at least two expansion elements (15) that can be expanded by inserting an expansion body (2) into an expansion channel (9) of the expansion anchor (1), wherein the expansion channel (9) extends concentrically and along a central longitudinal axis (L) of the expansion anchor (1), wherein the expansion elements (15) are separated from each other by a groove (21) defining a median plane between the expansion elements (15) where the longitudinal axis (L) is located, and wherein the expansion elements (15) are fully connected to each other by at least one net-shaped connector (22) disposed in the groove (21) between the two expansion elements (15), characterized in that the connector (22) has at least a first section (23) that is inclined at a first acute angle (a1) with respect to the central longitudinal axis (L),such that the central longitudinal axis (L) intersects the first section (23) at at least one point. Twelve claims follow.