Connector for two workpieces

Abstract

A connector (1) for two workpieces (2, 3) made of softer materials, comprising a first connector plate (4), which has a front side (7) for bearing against one workpiece (2, 3), an accessible rear side (8), and through-bores (9) for screwing to the workpiece (2), and a second connector plate (5), which has a front side (11) for bearing against the other workpiece (2, 3), an accessible rear side (12), and through-bores (13) for screwing to the other workpiece (3), wherein connector plates (4, 5) are either integral or have a coupling (6) for coupling to one another, and the front sides (7, 11) of the connector plates (4, 5) are each provided with a plurality of ribs (14) or knobs (15) projecting by 0.2 mm to 2.5 mm.

Description

[0001] Connector for two workpieces

[0002] The present invention relates to a connector for connecting two workpieces made of materials that are softer than the connector, comprising a first connector plate which has a front side for contact with one of the workpieces, a back side accessible when contacting one of the workpieces, and one or more through holes for screwing to one of the workpieces, and a second connector plate which has a front side for contact with the other of the workpieces, a back side accessible when contacting the other workpiece, and one or more through holes for screwing to the other workpiece, wherein the first and second connector plates are either designed as one piece with one another or have a coupling for coupling to the respective other connector plate.

[0003] One-piece connectors are either placed on two workpieces that have already been positioned relative to one another, with the first connector plate being screwed to one workpiece and the second connector plate being screwed to the other, the back of both connector plates being accessible, or the first connector plate is screwed to one workpiece from its accessible back, the two workpieces are then positioned relative to the desired workpiece, and the second connector plate is then screwed to the other workpiece from its accessible back. The connector plates can be aligned differently, i.e. they can lie in different planes if the workpieces are not flush with one another, or otherwise the entire connector can be flat, i.e. both connector plates lie in one and the same plane.In the case of first and second connector plates that can be coupled together, the first connector plate is first screwed to one workpiece and the second connector plate to the other workpiece, with both rear sides being accessible, and then the two workpieces are brought into the desired mutual position and the connector plates are coupled to one another via the coupling.

[0004] Connectors of the latter type are known, for example, from EP 1 856 417 B1, EP 3 456 892 A1 or EP 3 985 189 A1, and connectors of both types are marketed by Knapp GmbH, Euratsfeld, Austria. They are particularly suitable for creating connections in house construction or in timber engineering, including heavy-duty connections, for example for connecting main, secondary or cross beams, cross members, trusses, supports, posts, walls, facades, wall elements, etc., and for workpieces made of a variety of materials, primarily wood, but also plastics, composite materials, or even masonry.

[0005] In known connectors, the screws used to screw the connector plates to the respective workpieces essentially carry the load. If one of the workpieces is to be carried by the other workpiece via the connector, they are mainly subjected to shear stress. In order to increase the load-bearing capacity, the number, length or diameter of the screws or the area of ​​the connector plates can be increased, for example. However, all of these parameters are subject to strict limits, since increasing the number of screws or their thickness simultaneously weakens the workpieces, and their length or the area of ​​the connector plates is already limited by the workpiece dimensions.

[0006] The invention aims to further improve the load-bearing capacity of connectors of the type mentioned, so that they can permanently transmit greater forces with the same weight or the same size.

[0007] This aim is achieved with a connector of the type mentioned in the introduction, which is characterized in that the front sides of the first and second connector plates are each provided with a plurality of 0.2 mm to 2.5 mm projecting ribs or knobs. The screws used to screw the connector plates to the respective workpieces press the connector plates against the respective workpiece. The contact pressure causes the ribs or knobs to penetrate at least slightly into the surface of the softer materials of the workpieces. This significantly increases the static friction of the connector plates on the workpieces, so that the shear forces on the screws are significantly reduced. Tests by the inventors have shown that this increases the load-bearing capacity of the connectors by up to 40%, depending on the material of the workpieces and its homogeneity, for the same size.The connectors can permanently transmit larger forces and / or have a smaller overall size. Tests have also shown that ribs or studs that protrude too little from the front provide significantly less benefit; however, ribs or studs that protrude too far also lead to a reduced load-bearing capacity of the connector, as this weakens the surface structure of the workpieces, which in turn reduces static friction and the transferable forces.

[0008] It is particularly advantageous if the ribs or studs protrude by 0.6 mm to 2 mm, preferably 1 mm to 1.8 mm. Depending on the workpiece material, a protrusion of this magnitude increases static friction particularly effectively and permanently.

[0009] The tests also revealed that the distance between the ribs or studs influences the static friction. It is particularly advantageous if the ribs or studs are spaced 0.5 cm to 2 cm apart, preferably 0.8 cm to 1.3 cm apart. If the distance is too large, the effect is reduced, and fewer ribs or studs can be arranged on the front side. Conversely, if the distance is too small, the surface of the workpiece is weakened, which also reduces the effect of the ribs or studs.

[0010] The ribs or studs can have any shape in cross-section, e.g. rectangular or semi-circular. It is advantageous if the ribs or studs have a triangular, preferably a sawtooth-shaped cross-section. Ribs or studs of this shape penetrate the surface of the workpiece in question more easily, weakening it less than other shapes, but rather compacting and strengthening the surrounding surface areas. Overall, this leads to a more even surface contact of the front sides of the connector plates with the workpiece and to a particularly load-bearing connection. In the embodiment with studded front sides, the studs on each connector plate are preferably pyramid- or conical-shaped in order to ensure particularly easy penetration into the surfaces of the workpieces and high load-bearing capacities.

[0011] In the design with ribbed front sides, the ribs can have any desired shape, e.g., wave-like or zigzag; the ribs can also be interrupted and / or intersecting. It is advantageous if the ribs are straight and parallel to each other. This simplifies manufacturing and results in a uniform force transfer from one workpiece via the connector to the other.

[0012] This variant is particularly advantageous if the two connector plates are rectangular and the ribs run across the entire width of the front sides. This allows the connector plates and the connector to be manufactured simply and with minimal material consumption, e.g., by extrusion or casting, without the need for extensive post-processing to remove the material to create the ribs. Furthermore, the static friction of the front sides of the connector plates relative to the respective workpieces is maximized during vertical assembly.

[0013] It is particularly advantageous if, in the event that each of the two connector plates has a plurality of through-holes, at least one through-hole in each connector plate runs at an angle to its front side. This enables oblique tensile stress and thus oblique force transmission into the respective workpiece and, particularly if at least one of the workpieces is end grain wood, a considerably more durable, load-bearing screw connection to this workpiece. In the embodiment with a one-piece connector, i.e. the first and second connector plates are made in one piece with one another, the two connector plates can lie in planes that are inclined, offset and / or rotated relative to one another. The front sides of the two connector plates can also lie on different sides of the connector. On the other hand, it is advantageous if the first and second connector plates form a flat connector, with the front sides lying on one and the same side of the connector.This is easy to manufacture and enables such a connector to be used for a variety of common workpiece connections in which the workpieces lie flush against one another.

[0014] In this case, it is further advantageous if the at least one inclined through-bore of the first connector plate has an opposite slope to the at least one inclined through-bore of the second connector plate. In this way, increased tensile forces can be transmitted between the two workpieces.

[0015] In the embodiment in which the connector is in two parts, i.e. the first and second connector plates have a coupling for coupling to the respective other connector plate, it is particularly advantageous if the coupling on the first and second connector plates comprises at least one shoulder projecting parallel to their front side, behind which an undercut is formed on the front side, into which the shoulder of the respective other connector plate can be engaged. In this way, the connector plates can first be screwed individually to the respective workpiece and then anchored to one another by bringing the connector plates into engagement with one another with their shoulders and undercuts.

[0016] The shoulders can protrude at any point on the connector plates. In an advantageous variant, at least one shoulder protrudes from the edge connecting the front of one of the connector plates to its rear. A shoulder on the edge and the undercut formed on the front are particularly easily accessible for engaging the shoulder of the other connector plate.

[0017] In an advantageous variant, at least one of the connector plates is hook-shaped in side view and has a shoulder projecting from its hook parallel to its front, behind which a front undercut is formed into which a shoulder of the other connector plate can be engaged. The at least one connector plate can either have the shoulder and the undercut on the hook alone, or can have this as a further shoulder and further undercut if the shoulder and the undercut are also formed on its edge. Due to the hook shape, the connector plates can be coupled to one another particularly easily hook to hook or back to back in a space-saving manner, depending on the arrangement of the hook, and / or in conjunction with shoulders on the edge a particularly resilient double coupling can be achieved.

[0018] In an advantageous variant, the shoulder of one of the connector plates projecting from the hook is pierced by a through-hole, and the shoulder of the other connector plate projecting from the edge has a transverse notch on its crest. When screwed to the respective workpiece, the screw at the through-hole penetrating the shoulder absorbs transverse forces via the notch of the other connector plate, i.e. forces which act from the screw on the flanks of the notch, i.e. parallel to the front of the connector plate and transverse to the direction in which the shoulder projects, and thus prevent displacement of the two connector plates in this direction.

[0019] Preferably, both connector plates have the same shape. This simplifies handling, production, and storage.

[0020] It is advantageous if, in the case of straight and parallel ribbed front sides, the steps and undercuts extend parallel to the ribs across the entire width of the connector plates. This not only results in a particularly strong connection between the two connector plates due to the use of the entire connector plate width, but also in simple and material-saving production of the connector using an extrusion or casting process without extensive post-processing that removes material.

[0021] In a favorable variant, the first and / or the second connector plate each has one or more undercut recesses on their lateral edge sides, preferably T-slots running from the front to the back, and the connector further comprises at least one locking piece with opposite extensions corresponding to the recesses, which extensions can be used to lock two adjacent first or second connector plates in their recesses. The adjacent connector plates locked against each other have a mutual position defined by the locking piece(s), which facilitates assembly and ensures even loading of both adjacent connector plates during use.

[0022] It is advantageous if the locking pieces have screw holes so that they can be screwed to the respective workpiece when inserted into the recesses of two adjacent connector plates. This increases the load-bearing capacity of the connector plates by transferring additional force to the respective workpiece. Furthermore, the smaller, easier-to-handle locking pieces can be screwed to the respective workpiece first and serve as a template for the connector plates that are subsequently screwed to the workpiece, their position being thus determined in advance.

[0023] The invention is explained in more detail below with reference to exemplary embodiments shown in the accompanying drawings. In the drawings: Figs. 1a and 1b show a first variant of a connector according to the invention for two workpieces in a longitudinal section (Fig. 1a) and a perspective view obliquely from the front (Fig. 1b), respectively;

[0024] Fig. 2 shows an alternative variant of the connector of Figs. 1a and 1b in its position screwed to the two workpieces in a longitudinal section; Figs. 3 and 4 each show a variant of a further embodiment of the connector according to the invention, each in the position screwed to the workpieces in a longitudinal section; Figs. 5a to 5c show a further variant of the embodiment of the connector of Figs. 3 and 4, namely a connector plate in side view (Fig. 5a) and in a perspective view obliquely from the rear (Fig. 5b) and two connector plates coupled to one another in the perspective view of Fig. 5b (Fig. 5c);

[0025] Fig. 6 shows a variant of the connector plate of Figs. 5a and 5b in rear view; and Figs. 7 to 10 each schematically show variants of the design of the front sides of the connectors of Figs. 1 to 6, in front view (Figs. 7a, 8a and 9a), side view (Figs. 7b, 8b, 9b), or partially in side view (Figs. 10a to 10c).

[0026] 1 to 4 and 5c show a connector 1 for connecting two workpieces 2, 3. The workpieces 2, 3 are made of a material which is softer than the material of the connector 1. The workpieces 2, 3 can be made of wood, in particular glued laminated timber, plastic, composite material, masonry or the like. These are, for example, main beams, secondary beams or cross beams, cross members, trusses, supports, posts, walls, facades, wall elements etc. which are connected with the aid of the connector 1. The connector 1 itself can also be made of various materials, in particular plastic or composite material; usually, however, it is made of metal, in particular steel or aluminum, e.g. high-strength aluminum. The connector 1 comprises a first connector plate 4 and a second connector plate 5. In the example of Figs. 1a, 1b and 2, the connector 1 is in one piece, ie the first and second connector plates 4, 5 are made in one piece with each other.In the examples of Fig. 3 and 4, however, the two connector plates 4, 5 are separate from each other and have a coupling 6 with which one connector plate 4, 5 is coupled to the other connector plate 5, 4, as described in more detail below.

[0027] In all embodiments, the first connector plate 4 has a front side 7, with which it can be brought into contact with one of the workpieces 2, 3 (here: the workpiece 2), and a rear side 8, which is accessible when the front side 7 is in contact with the one workpiece 2. Furthermore, the first connector plate 4 has one or (as here) several through-holes 9 for screws 10, by means of which it can be screwed to the one workpiece 2 from its accessible rear side 8 (Figs. 2 to 4).

[0028] Similar to the first connector plate 4, the second connector plate 5 also has a front side 11 for contact with the other of the workpieces 2, 3 (here: the workpiece 3), a rear side 12 accessible when contacting the other workpiece 3 and one or more through holes 13 for screwing to the other workpiece 3.

[0029] The front sides 7, 11 of the first and second connector plates 4, 5 are each provided with a plurality of 0.2 mm to 2.5 mm protruding ribs 14 or knobs 15 (Fig. 8a). When the front sides 7, 11 are screwed to the respective workpieces 2, 3 using the screws 10, the connector plates 4, 5 are pressed against the respective workpiece 2, 3. Due to the contact pressure, the ribs 14 or knobs 15 penetrate the surface of the softer material of the workpieces 2, 3. This significantly increases the static friction of the connector plates 4, 5 with respect to the workpieces 2, 3, so that shear forces occurring on the screws 10 under load are significantly reduced.

[0030] In the examples of Fig. 1a, 1b and 2, the first and second connector plates 4, 5 lie in one and the same plane and thus form a planar connector 1. In these examples, a transition between the first and second connector plates 4, 5 is not immediately apparent. However, alternatively, in the case of a planar connector 1, this could, for example, be L-shaped or T-shaped in front view, with the first connector plate 4 forming one leg of the L or T and the second connector plate 5 forming the other leg of the L or T, or could have any other shape, e.g., oval, round, semicircular, diamond-shaped, etc.

[0031] Instead of forming a flat connector 1, the first and second connector plates 4, 5 could be offset parallel to one another, inclined relative to one another, i.e. the connector 1 could be bent along the bend line K symbolically shown in Fig. 1b, and / or rotated, i.e. the connector 1 could be twisted between the first and second connector plates 4, 5 about, for example, a central vertical axis A. In the examples shown, the front sides 7, 11 of the two connector plates 4, 5 are located on one and the same side of the connector 1; alternatively, they could be located on opposite sides of the connector 1.

[0032] In the examples of Fig. 1 to 6, the two connector plates 4, 5 are each substantially rectangular with a width B, a length L and a thickness D which is significantly smaller than width B and length L due to their plate shape. The projecting ribs 14 can run in a straight line as shown or, for example, in a wave-like, zigzag shape, etc. over the front sides 7, 11 of the two connector plates 4, 5 and can be parallel to one another or at an oblique angle or can cross one another.

[0033] Although each connector plate 4, 5 could be screwed to the respective workpiece 2, 3 using just a single screw 10, in the examples shown, each of the two connector plates 4, 5 has a plurality of through-holes 9, 13, of which optionally at least one through-hole 9, 13 of each connector plate 4, 5 runs obliquely to its front side 7, 11. In the example in Fig. 1b, the through-holes 9, 13 pass straight through the first and second connector plates 4, 5 along the central axis A, i.e., normal to the respective front side 7, 11, and the through-holes 9, 13 arranged laterally of the axis A pass through the respective connector plate 4, 5 obliquely to its front side 7, 11. However, this is only one of many possible variants of the arrangement and orientation of the through-holes 9, 13.

[0034] In the example of Fig. 2, the at least one (here: four) obliquely running through-bore(s) 9 of the first connector plate 4 has a slope which is opposite to the at least one (here: four) obliquely running through-bore(s) 13 of the second connector plate 5, in that the obliquely running through-bores 9 of the first connector plate 4 are oriented upwards in the direction of the first workpiece 2 and the through-bores 13 of the second connector plate 5 are oriented downwards in the direction of the other workpiece 3.

[0035] 3 to 6 show different variants of the embodiment in which the connector 1 has two separate connector plates 4, 5 coupled to one another via the coupling 6, whereby the two workpieces 2, 3 are anchored or can be anchored to one another. For this purpose, firstly the first connector plate 4 is screwed to one workpiece 2 and the second connector plate 5 is screwed to the other workpiece 3, and then the connector plates 4, 5 are coupled to one another in order to anchor the two workpieces 2, 3 to one another. The coupling 6 comprises at least one shoulder 16, 17 on each of the first and second connector plates 4, 5, which projects parallel to the front side 7, 11 of the respective connector plate 4, 5 and behind which an undercut 18, 19 is formed on the front side, ie from the perspective of the shoulder 16, 17 in the direction of the respective front side 7, 11.The shoulder 17, 16 of the other connector plate 5, 4 is engaged in the undercut 18, 19 in order to couple them together.

[0036] In the example of Fig. 3, the shoulder 16, 17 projects from the edge which connects the front side 7, 11 of the respective connector plate 4, 5 with its rear side 8, 12. The shoulder 16, 17 can project all the way around the respective connector plate 4, 5 from its all-round edge; generally, a shoulder 16, 17 is only provided on one edge of the connector plate 4, 5. In the example shown, the shoulder 17 projects upwards on the upper side of the second connector plate 5, which is the lower one here, parallel to its front side 11 and forms the aforementioned undercut 19 on the front side. The shoulder 17 has approximately half the thickness D of the second connector plate 5 or less and can optionally decrease in thickness towards the outside.

[0037] In this example, the first connector plate 4 is shaped the same as the second connector plate 5, but is turned upside down, so that its shoulder 16 protrudes on the underside parallel to its front side 7 and forms the front undercut 18. In the engaged position shown, the respective shoulders 17, 16 engage in the undercuts 18, 19 of the other connector plate 4, 5. The shoulders 16, 17 and undercuts 18, 19 can extend either across the entire width B of the connector plates 4, 5 or only across part of it.

[0038] It is understood that shoulders 16, 17 and undercuts 18, 19 can also be shaped and formed differently. For example, the shoulders 16, 17 could be formed on the lateral sides of the connector plates 4, 5; this is conceivable based on the illustration of the connector 1 in Fig. 3, if this view were understood as a plan view. Or, for example, the lower (second) connector plate 5 could have on its upper side a U- or V-shaped notch (not shown when viewed from the front) with a shoulder 17 parallel to the front side 11 and a front undercut 19, and the upper (first) connector plate 4 could have a corresponding mushroom-shaped projection protruding from its rear side 8, wherein the head of the mushroom can engage as shoulder 16 in the undercut 19 of the notch and at the same time forms the undercut 18 for the shoulder 17 of the second connector plate 5.In this case, the upper and lower connector plates 4, 5 could also be swapped or both connector plates 4, 5 could have the same shape, i.e. each have a U- or V-notch as well as a mushroom-shaped projection.

[0039] Fig. 4 shows a further variant of the connector plates 4, 5 with (here: double) coupling 6. In this variant, the second connector plate 5, which is again the lower one, is hook-shaped in side view (here: shown in longitudinal section) and has a corresponding further shoulder 21 projecting from its hook 20 parallel to its front side 11, behind which a further front undercut 22 is formed. Furthermore, the second connector plate 5 has the shoulder 17 with undercut 19 on its upper side, as previously described with reference to Fig. 3. The first connector plate 4 is again shaped the same and turned upside down and thus also has a further shoulder 24 and a further undercut 25 on its hook 23.When the two connector plates 4, 5 are coupled to one another, the further shoulder 24 of the first connector plate 4 engages in the undercut 19 on the upper side of the second connector plate 5 and, conversely, the shoulder 17 of the second connector plate 5 engages in the further undercut 25 of the first connector plate 4. At the same time, the further shoulder 21 of the second connector plate 5 engages in the undercut 18 on the underside of the first connector plate 4 and, conversely, the shoulder 16 of the first connector plate 4 engages in the further undercut 22 of the second connector plate 5. The two connector plates 4, 5 are thus doubly coupled to one another; their respective rear sides 8, 12 lie against one another.Alternatively, in this variant, if double coupling is not desired or required, the additional shoulders 21, 24 could each be engaged with the additional undercuts 22, 25, and the edge shoulders 16, 17 and undercuts 18, 19 could optionally be omitted. Furthermore, the two connector plates 4, 5 could be shaped differently, e.g., only the upper first connector plate 4 could be hook-shaped with an additional shoulder 24 and without an edge shoulder 16, and the lower second connector plate 5 could be non-hook-shaped but with an edge shoulder 17, or vice versa.

[0040] In a further variant of the connector plates 4, 5 coupling 6 according to Fig. 5a to 5c, the (here again lower) second connector plate 5 is hook-shaped in cross-section, similar to the example in Fig. 4, but the hook 20 in this variant is optionally not formed on the underside of the connector plate 5, but rather slightly offset upwards from the underside. As in the example in Fig. 4, the connector plate 5 has a further shoulder 21 projecting from the hook 20 parallel to its front side 11, behind which the further front undercut 22 is formed, and on its upper side the shoulder 17 with undercut 19. As in all examples, the second connector plate 5 has one or more through-holes 13, wherein in this example one of the through-holes (identified by the reference numeral 13') penetrates the further shoulder 21 projecting from the hook 20 (here: centrally).Furthermore, the connector plate 5 has a transverse notch 26 on its shoulder 17 on its crest, ie a notch 26 in the edge penetrating the shoulder 17 from the rear side 12 to the undercut 19, as explained below.

[0041] As shown in the example in Fig. 5c, the (here: upper) first connector plate 4 of this example is optionally again shaped the same as the second connector plate 5 and turned upside down in the engaged position shown. As previously explained using the example in Fig. 4, the two connector plates 4, 5 are optionally coupled to one another in a double manner; their rear sides 8, 12 partially abut one another. The notch 27 in the shoulder 16 (facing downwards in the position shown) of the first connector plate 4 corresponds to the through-hole 13' of the second connector plate 5, so that a screw 10 (not shown) screwed through this through-hole 13' is encompassed by the flanks of the notch 27 of the shoulder 16 of the first connecting plate 4. The same applies analogously to the notch 26 of the second connector plate 5 (not visible in Fig. 5c) and the screw (not shown) in the through-hole 9' of the first connecting plate 4.In this way, the screw 10 in the through-hole 13' of the second connector plate 5 and that in the similar through-hole 13' of the first connector plate 4 secure the two connector plates 4, 5 and thus the workpieces 2, 3 against displacement in the direction of their width B.

[0042] It is understood that instead of or in addition to the single through-hole 9', 13' for a screw 10, each connecting plate 4, 5 may have multiple through-holes 9', 13' and / or one or more fixed bridges transversely spanning the respective further undercut 22, 25. Furthermore, the through-hole 9', 13' could alternatively be formed on the edge-side shoulder 16, 17, and the notch 26, 27 could be formed on the further shoulder 21, 24 projecting from the hook 23, 20.

[0043] Fig. 6 shows an example in which each (here: second) connector plate 5 has one or more (here: two) undercut recesses 28 on its edge (here: on each lateral side). In the example shown, the recesses 28 are each T-shaped grooves that penetrate the second connector plate 5 from its front to its rear side 11, 12; alternatively, the grooves may not be T-shaped and / or may not penetrate completely. If two connector plates 5 with such recesses 28 are placed next to one another, they can be locked against one another using one or more (here: two) locking pieces 29. For this purpose, each locking piece 29 has extensions 30 that correspond to the recesses 28 and can be inserted into the recesses 28. Finally, the locking pieces 29 optionally have screw holes 31 in order to be screwed to the workpiece 3 in their position inserted into the recesses 28 of two adjacent connector plates 5.Similar recesses for corresponding locking pieces can also be provided on the first connector plate 4 (not shown). Furthermore, the recesses 28 and locking pieces 29 of this type can be used for connector 1 of all embodiments.

[0044] It will be apparent to those skilled in the art that further variants—including combinations of the examples shown—of the connector plates 4, 5 are possible. In particular, as mentioned, the first and second connector plates 4, 5 can be shaped differently from one another.

[0045] In the examples of Figs. 7 to 10, various variants of the ribs 14 and studs 15 are symbolically shown without any through-holes 9, 13 and without distinguishing between the first and second connecting plates 4, 5; these are to be understood merely as examples and not as limiting. As explained above, the ribs 14 or knobs 15 project 0.2 mm to 2.5 mm from the front sides 7, 11 of the connector plates 4, 5, ie they have a height H of 0.2 mm to 2.5 mm compared to the front side 7, 11 of the respective connector plate 4, 5. In particular, 0.6 mm to 2 mm, preferably 1 mm - 1.8 mm can project, e.g. 1.2 mm or 1.5 mm etc. How far the ribs 14 or knobs 15 project from the front sides 7, 11 of the connector plates 4, 5 depends in particular on the hardness and brittleness of the workpieces 2, 3.

[0046] The ribs 14 can, as shown in Fig. 1b, run across the entire width B or, as shown in Fig. 7a, across a large part of the width B of the front sides 7, 11 of the connector plates 4, 5. Alternatively, the ribs 14 can only run over a small part of the width B of the front sides 7, 11 and / or, as in the example in Fig. 9a, be interrupted. Likewise, the ribs 14 or, as in the example in Fig. 8a, the knobs 15 can be evenly distributed over the front sides 7, 11 of the first and second connector plates 4, 5 or, alternatively, can only be located at certain points on the front side 7, 11, e.g. around the through-holes 9, 13 and / or close to the edges of the front sides 7, 11. Furthermore, both ribs 14 and knobs 15 could be formed on the front side 7, 11 of one and the same connector plate 4, 5.

[0047] In the examples shown, the ribs 14 or knobs 15 are spaced apart from each other by 0.5 cm to 2 cm, preferably 0.8 cm to 1.3 cm, and in this case, in particular, by approximately 1 cm. This means that the tips of the ribs 14 or knobs 15 are spaced apart from adjacent ribs 14 or knobs 15 by a distance X of the specified size.

[0048] The cross-section of the ribs 14 or knobs 15 can be semicircular or semi-oval; in the example of Fig. 10a, however, the cross-section is triangular and in the example of Fig. 10b, in particular, it is sawtooth-shaped. Alternatively, the ribs 14 or knobs 15 can also have a rectangular or other cross-section, for example, as shown in Fig. 10c. The knobs 15 can, for example, be dome-shaped or conical, or, as shown in Figs. 8a and 8b, pyramid-shaped. Furthermore, the tips of the knobs 15 or the ridges of the ribs 14 can be either sharp-edged or, as shown in the examples in Figs. 7b, 8b and 9b, rounded.

[0049] The invention is not limited to the embodiments shown, but includes all variants, modifications and combinations thereof that fall within the scope of the appended claims.

Claims

Patent claims:

1. A connector for connecting two workpieces (2, 3) made of softer materials than the connector (1), comprising a first connector plate (4) having a front side (7) for engagement with one of the workpieces (2, 3), a rear side (8) accessible when engaged with one workpiece (2), and one or more through-holes (9) for screwing to one workpiece (2), and a second connector plate (5) having a front side (11) for engagement with the other of the workpieces (2, 3), a rear side (12) accessible when engaged with the other workpiece (3), and one or more through-holes (13) for screwing to the other workpiece (3), wherein the first and second connector plates (4, 5) are either formed integrally with one another or have a coupling (6) for coupling to the respective other connector plate (5, 4), characterized in that the front sides (7, 11) of the first and second connector plates (4, 5) each with several 0.2 mm to 2,5 mm projecting ribs (14) or knobs (15).

2. Connector according to claim 1, characterized in that the ribs (14) or knobs (15) protrude 0.6 mm to 2 mm, preferably 1 mm to 1.8 mm.

3. Connector according to claim 1 or 2, characterized in that the ribs (14) or knobs (15) are spaced apart from each other by 0.5 cm to 2 cm, preferably 0.8 cm to 1.3 cm.

4. Connector according to one of claims 1 to 3, characterized in that the ribs (14) or knobs (15) have a triangular, preferably a sawtooth-shaped cross-section.

5. Connector according to claim 4, wherein the front sides (7, 11) are provided with knobs (15), characterized in that the knobs (15) are pyramid-shaped or conical.

6. Connector according to one of claims 1 to 4, wherein the front sides (7, 11) are provided with ribs (14), characterized in that the ribs (14) are rectilinear and parallel to one another.

7. Connector according to claim 6, characterized in that the two connector plates (4, 5) are rectangular and the ribs (14) run transversely across the entire width (B) of the front sides (7, 11).

8. Connector according to one of claims 1 to 7, wherein each of the two connector plates (4, 5) has a plurality of through-bores (9, 13), characterized in that at least one through-bore (9, 13) of each connector plate (4, 5) runs obliquely to its front side (7, 11).

9. Connector according to claim 8, wherein the first and second connector plates (4, 5) are made in one piece with each other, characterized in that the first and second connector plates (4, 5) form a flat connector (1), wherein the front sides (7, 11) lie on one and the same side of the connector (1).

10. Connector according to claim 9, characterized in that the at least one obliquely running through-bore (9) of the first connector plate (4) has an opposite slope to the at least one obliquely running through-bore (13) of the second connector plate (5).

11. Connector according to one of claims 1 to 10, wherein the first and second connector plates (4, 5) have the coupling (6) for coupling to the respective other connector plate (5, 4), characterized in that the coupling (6) on the first and second connector plates (4, 5) comprises at least one shoulder (16, 24; 17, 21) projecting parallel to their front side (7, 11), behind which an undercut (18, 25; 19, 22) is formed on the front side, into which the shoulder (17, 21; 16, 24) of the respective other connector plate (5, 4) can be engaged.

12. Connector according to claim 11, characterized in that at least one shoulder (16, 17) projects from the edge which connects the front side (7, 11) of one of the connector plates (4, 5) to its rear side (8, 12).

13. Connector according to claim 11 or 12, characterized in that at least one of the connector plates (4, 5) is hook-shaped in side view and has a shoulder (21, 24) projecting from its hook (23, 20) parallel to its front side (7, 11), behind which a front undercut (22, 25) is formed, into which a shoulder (17, 21; 16, 24) of the respective other connector plate (5, 4) can be engaged.

14. Connector according to claim 13 in conjunction with claim 12, characterized in that the shoulder (21, 24) projecting from the hook (23, 20) of one of the connector plates (4, 5) is penetrated by a through-bore (13', 9') and the shoulder (16, 17) projecting from the edge of the other connector plate (5, 4) has a transverse notch (27, 26) on its crest.

15. Connector according to one of claims 11 to 14, characterized in that both connector plates (4, 5) have the same shape.

16. Connector according to one of claims 11 to 15 in conjunction with claim 7, characterized in that the shoulders (16, 24; 17, 21) and undercuts (18, 25; 19, 22) extend parallel to the ribs (14) transversely over the entire width (B) of the connector plates (4, 5).

17. Connector according to one of claims 1 to 16, characterized in that the first and / or the second connector plate (4, 5) has on its lateral edge sides one or more undercut recesses (28), preferably T-grooves running from the front to the rear (7, 11; 8, 12), and in that the connector (1) further comprises at least one locking piece (29) with opposite extensions (30) corresponding to the recesses (28), which extensions (30) for locking two adjacent first or second connector plates (4, 5) can be inserted into their recesses (28).

18. Connector according to claim 17, characterized in that the locking pieces (29) have screw holes (31) in order to be screwed to the respective workpiece (2, 3) in their position inserted into the recesses (28) of two adjacent connector plates (4, 5).

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