Fastening element

0001The invention relates to a fastener for hard surfaces, in particular for concrete, stone, masonry or the like, according to the preamble of claim 1.

0002For securing components to hard surfaces such as concrete, Stone, brick masonry and the like, anchors are usually as fasteners used. These usually have from a sleeve-shaped dowel body Metal or steel which is anchored in a prepared bore in the ground, and load application means that, for fixing the component to the actual fastener For example, a screw, a bolt or the like cooperate. The load application means are usually internally threaded in the inner wall the bore is provided with a sleeve-shaped dowel body are provided. It However, other types of load application means, such as bayonet connectors or other like form-fit connections may be provided. A Another type of conventional load application means are, for example, also pluggable Quick release buckles with resiliently engaging in the structuring of a threaded rod Locking elements and the like. The anchoring of the dowel in the underground usually takes place via a radial expansion of an expansion area at in the setting direction front end portion of the anchor body. For this, a usually conical Expanding element under radial spreading of the expansion region in a bore of the sleeve-shaped dowel body moved. The expansion cone is usually already within arranged the bore and is hitting advanced into the bore. at so-called outer cone plugs is the expansion body at the front end of the anchor body clamped. For anchoring of such fasteners in the underground is the most metallic, sleeve-shaped dowel body over which the bottom of a hole supporting expansion body of metal driven. It is the spread radially expanded.

0003The relative displacement between the sleeve-shaped dowel body and the conical Expanding body is carried out by axial blows, with which the expansion cone in the propelled bore or the anchor body is distended to the spreader. The striking setting process, the fasteners described not suitable for every surface. In brickwork, for example, there is by the force of the axial strokes often cause damage to the brick. is After no safe anchorage longer possible. But even in porous sandstone or the like Substrates may by axial blows to the spreader or come on the sleeve-shaped dowel body damage, leading to it; that the required load values ​​are not attained. The non-positive anchoring this anchor genus underground by radial spreading of the expansion of the Dowel body is disadvantageous in many applications. Due to the relatively high Spreading forces have met predetermined minimum edge and minimum center be to ensure the security of the attachment point can. This limits the possibilities for mounting components often undesirably on.

0004For the creation of fixtures with low edge distances and spacings is at a second type of fasteners a largely without expansion, interlocking anchoring provided. is In so-called undercut anchors the positive anchoring is that the dowel body envisaged expansion tabs in a, usually mounted in the vicinity of the borehole ground undercut to be issued. The undercut in the substrate must be previously separately, with Help create special undercut equipment downhole. This type of Fasteners is very time consuming and costly. It is therefore usually Only in especially sensitive fasteners and particularly for heavy duty fixings applied.

0005The prior art also form-fitting anchoring fasteners known that without the separate preparation of an undercut in a bore be anchored in the ground. Such fasteners are for example described in EP-A-1174626. They have a cylindrical substantially Dowel body which is provided with an axial bore. An internal thread in the bore serves as load application means. In a first embodiment, the fastening elements is described on the outside of the anchor body a helically encircling cutting provided. On setting direction side end facing away from the dowel body an inner plea for Setting tools on. A second described fastener includes a two-part dowel body having distinguishable union diameters. To a cylindrical Stem closes against the setting direction a substantially cylindrical connector at. The outside of the cylindrical shaft is helical with at least one revolving cutter provided. The cylindrical connection part has a Blind hole, which is provided with an internal thread. At the bottom of the blind bore the connecting part is provided a plea for setting tools. The fasteners described are turning in a prepared receiving bore screwed. It digs the anchor on the body or on cylindrical Shaft provided for cutting into the borehole wall and generates a substantially interlocking anchoring. done The actual definition of a component a screw or the like, in the blind hole of the dowel body and the connection part is screwed.

0006Furthermore, so-called concrete screws are known from the prior art. These have a cylindrical shank, the outside of which having at least one helical cutter is provided. On setting direction side end remote the shank on a commonly designed as a hexagonal head. The head serves as a plea for transmitting torque when screwing in the concrete screw in a prepared receiving bore and simultaneously establishing a Component. When screwing the edge digs into the wall of the receiving bore and thus produces a substantially interlocking anchoring.

0007A disadvantage of these known from the prior art, self-tapping fasteners or concrete screws is that they have a large during the setting process tilt trend and like a top, more or less in the setting process regularly präzesieren about its axis. Thus, the setting process is much more difficult. is By tilting of the fastener or the concrete screw during the setting process, the receiving bore at its mouth and a not inconsiderable Length of its axial extent radially expanded. This can cause that the fastening element in its setting direction side rear portion is no longer anchored in the wall of the receiving bore and the required Holding values ​​no longer be achieved.

0008To counteract the tendency to roll over during the setting process, are in another known from the prior art fixing member at the outside of the Dowel body provided three helically encircling cutting, at the plug tip expire on a peripheral circuit. Thereby, the fastening element when applying to the receiving bore a three-point support on. When setting process dig the three cutting simultaneously and uniformly in the wall of the Receiving bore a. A tilting of the fastener can thereby largely be avoided. The manufacture of the fastener with three helically revolving cutting is relatively complicated and expensive the product.

0009It is therefore an object of the present invention, these disadvantages of the fastening elements of the prior art to be remedied. There is a fastener created will allow that mounts with small edge distances and spacings. To overturn the tendency of the fastener during the setting process and about its to präzesieren axis should be largely eliminated. Here is the fastener be easy and inexpensive to produce.

0010The solution to these problems consists in a fastening element in the having the characterizing portion of claim 1. recited features. Further developments and / or advantageous embodiments of the invention are Subject of the dependent claims.

0011The invention proposes a fastening element for hard constructional, especially for concrete or the like, in which a substantially cylindrical body comprises, at the circumferential surface of at least one helically encircling is cutting provided. The cutting edge extends from a setting direction front end portion of the body toward its rear end. A plea serves for a setting tool during the setting process for the transmission of torque. The plea is essentially on the same axial height of the Body arranged as an outlet of cutting the front end portion of the body.

0012By the engagement means for a setting tool for torque transmission during arranged setting process substantially at the same level with the outlet of the cutting edge is the tendency to roll over the fastener is reliably counteracted. In contrast to the fasteners of the prior art is characterized the torque in the immediate vicinity of the engagement of the cutting edge in the wall of a prepared receiving bore initiated. When setting process Therefore, the fastening element in a very stable position; a Präzesion his Axis due to tilt out of axial alignment is largely avoided. Thereby, even when a fastener having only a peripheral Cutting a widening of the receiving bore can be prevented through the estuary. By introducing torque in the immediate vicinity of Cut outlet at the front end portion of the body of the fastener engages the cutting optimally in the wall of the receiving bore and a stabilized so the fastener immediately after the start of the setting process in addition. On Multiple cuts, for example, three cutting to achieve a three-point support, before the start of the setting process can be omitted. Characterized the fastening element relatively simple and inexpensive to produce. For example, the Fastener encircling the single helical cutting in a Cold-forming process are made of steel. For special operating conditions the fastening element may also consist of a stainless steel alloy or the like be prepared.

0013The plea for transmitting torque comprises expediently a polygonal Cross-sectional contour. Preferably, the cross-sectional contour is regularly polygonal, in particular three-, four-, five- or hexagonal configuration. Setting tools with such a cross-sectional contours are well known and in different Diameters available. However, the load application means may also have other cross-sectional contours exhibit. In principle, all known from the screwdriving open Suitable cross-sectional contours. Examples include simple or crossed Slots, Torx contours, star-shaped contours and the like. In the selection of Cross-sectional contour in addition to the availability of setting tools usually also the largest possible total area targeted for torque transmission, the can be written in a predetermined diameter.

0014The plea is advantageously arranged within the body of the fastener and achievable by opening out at the rear end of the body bore. This variant is in a classic cylindrical concrete screw with hexagonal head as implemented as a self-cutting dowel-like Embodiment of the fastening element.

0015In a variant of the fastener as a self-tapping screw-in the bore in the body of the securing element has a diameter , which is larger than a diameter of the engagement means. This allows the Setting tool freely through the mouth of the bore at the rear end imported the body and brought into engagement with the engagement means. The Setting tool can, for example, very easy on the type of known be designed screwing.

0016The bore in the body is equipped with a load application means, which preferably against the setting direction rearwardly adjoins the plea. The Load application means, a quick fastener on a clamping form-fitting base, a bayonet connection or the like. In a preferred embodiment, the fastener is the load application means an internal thread. The internal thread can be incorporated as a coarse thread, a Whitworth thread, a metric thread be or the like. Thread as load application means offer Advantage that a fixed on fastener component very simply by dissolving the screwed fastening screw can be disassembled.

0017By the front end portion of the body of the fastener to the front End tapers formed, is setting and screwing the fastener facilitated in the prepared location hole in the ground. The tapered design of voderen end portion also includes doing chamfers or a dome-shaped or similar training of the front end of the body.

0018The helically encircling edge advantageously extends over a substantial Part of the longitudinal extension of the body of the fastener. The cutting digs while rotating the setting process in the wall of the prepared receiving bore and creates a positive anchor. The length of the positive Anchor in the receiving bore is a measure of the achievable load values.

0019As already explained in the foregoing, the inventive design also suitable for self-tapping dowel shaped variants as for the well known from the prior art so-called concrete screws which set about their mostly hexagonal head a component. In a variant of Concrete screws, the body is provided with an axial bore opening at the top. The plea is accessible via this hole. The bore has thereby expediently substantially over its entire from the rear end the body to attack means extending length a cross-section, of the one the plea corresponds. The approximately at the same height as the outlet the cutting edge arranged plea consists in this embodiment, the the rear end of the concrete screw continued. The resulting total to Torque transmission is relatively large in this embodiment.

0020The engagement means is a at the rear end of the body of the fastener which opens axial bore accessible. Here, the hole as a through hole be formed. Preferably, the axial bore in the body, however, designed as a blind hole and the plea at the base of the blind bore arranged. In this embodiment, the position of engagement is the setting tool uniquely determined by the attacking agent, and it is optimal Torque transmission in the immediate vicinity of the outlet of the cutting guaranteed.

0021Further advantages and features will become apparent from the following description of a exemplary embodiment of the invention with reference to the only schematic drawing showing an axial section of a self-tapping Dowel formed fastener shows.

0022The trained as self-cutting dowel fastener bears overall the reference numeral 1. The plug 1 has a substantially cylindrical body 2 is on, formed on its peripheral surface a helically encircling cutting. 7 The self-tapping anchor 1 is shown in the use position, its front portion 3, in the setting direction S. The blade 7 comprises the front portion 3 an outlet 71 and extends counter to the setting direction S toward the 1 rear end of the body 2. The cutting edge 7 extends with advantage over a substantial part of the longitudinal extension of the body 2 of the anchor. The Design of blade 7 is known per se from the prior art. The biggest radial projection of the helically extending cutting edge 7 is for example about 1.5 mm to about 4 mm. The radial extension of the cutting edge 7 takes on the outlet 71 substantially to zero. This facilitates the rotating set of self-tapping Dowel 1 burying the blade 7 in the wall of the hard ground, For example concrete, stone, masonry or the like, started receiving bore.

0023The illustrated self-tapping anchor 1 has a blind hole 5, with an internal thread 6 is provided as a load application means. The internal thread is running at the mouth of the blind hole 5 at the rear end 4 of the body 2. At the bottom of the blind hole 5 a plea 8 for a setting tool is arranged. In the illustrated embodiment, the plea 8 a polygonal, in particular a hexagonal, cross-sectional contour.

0024However, the load application means may be other polygonal cross-sectional contours, for example, have three, four, five-sided, etc. cross-sectional contours. in principle are all made of bolting known open cross-sectional contours suitable. Examples include simple or crossed slits Torx contours stellate Contours and the like. In selecting the cross-sectional contour is adjacent to the Availability of setting tools generally also the largest possible total sought for torque transmission, the predetermined in a diameter is written.

0025Unlike the self-tapping fasteners for hard surfaces of the prior art is self-tapping in the inventive Fastening means 1, the engagement means 8 is substantially at the same axial height arranged as the outlet of the cutting edge 7. This has the great advantage that the Torque introduction substantially in the immediate vicinity of the outlet 71 of the cutter 7 is performed. Thus, the plug 1 is already before the start of the setting process stabilized, and a tilting and Präzesieren about its axis is prevented. By the optimal torque introduction the cutting 7 digs at the beginning of the rotating Setting process quickly and stabilized in the wall of the receiving bore the dowel 1 in addition.

0026The diameter d of the blind hole 5 is larger than the diameter or the Width w of the plea 8. Thus, the setting tool is very simple to the depths the blind hole 5 introduced to it to engage with the engagement means 8 bringing torque transmission. The substantially cylindrically shaped Body 2 of the self-tapping anchor 1 is tapered at its front portion 3 formed or chamfered. This simplifies the insertion of the anchor 1 to the prepared Receiving bore.

0027The inventive fastening element is usually made of steel. For special Applications can also be a corrosion-resistant steel are used.

0028The manufacturing of the anchor is done is done, for example, a metal-cutting Process or preferably in a low-cost cold forming.

0029The invention is an example of a self-tapping anchor with an internally threaded bore explained. It is understood that the inventive arrangement the plea also with so-called concrete screws with usually a hexagon trained head can be provided. The load application means described can be used as a coarse thread, a Whitworth thread, a metric thread or the like be formed. Thread as load application means offer the advantage that the fastener fixed component very simply by loosening the screwed Fastening screw can be disassembled. In addition to an internal thread can the load application means a quick fastener on a clamping form-fitting base, a bayonet connection or the like.

0030By at the inventive fastener the plea for a Setting tool for torque transmission during the setting process to substantially the same amount is arranged with the outlet of the cutting, the tendency to roll over is the fastener reliably counteracted. In contrast to the fasteners of the prior art is thus the torque in the immediate Neighborhood of engagement of the cutting into the wall of a prepared Receiving bore initiated. During the setting process, the fastener has therefore a very stable situation, a Präzesion about its axis due to tilting of the axial Orientation is largely avoided. Thereby, it also comes with fasteners with only a peripheral edge to any expansion of the receiving bore the estuary. By introducing torque in the immediate Neighborhood for cutting outlet at the front end portion of the body of the fastening element engages the cutting optimally in the wall of the receiving bore and thus stabilizing the fastener immediately after the start the setting process additionally. In multiple cuts, particularly three cutting to achieve a three-point support before the start of the setting process can be waived will. Thus, the fastener is relatively simple and inexpensive producible.