DD249072A1

DD249072A1 - Expansion Plugs

Info

Publication number: DD249072A1
Application number: DD29013086A
Authority: DD
Inventors: Thilo Spittel; Rudolf Kirsch; Manfred Jentzsch; Manfred Recknagel; Bodo Recknagel; Volker Schulze
Original assignee: Elbenaturstein Dresden Veb
Priority date: 1986-05-12
Filing date: 1986-05-12
Publication date: 1987-08-26

Abstract

Die Erfindung bezieht sich auf einen Spreizduebel, der in Bauwerksteile aus Beton, Stahlbeton, Mauerwerk, Natur- oder Kunststein entsprechender Festigkeit zur Verankerung von Gegenstaenden eingesetzt wird. Der Hauptmangel der bisher verwendeten Spreizduebel fuer o. g. Anwendungszweck besteht darin, dass auf Grund unguenstiger Gestaltung des Duebels durch Kerbwirkung die Festigkeitseigenschaften des Duebels ungenuegend genutzt werden. Durch Verminderung der Formzahl wird eine gleichmaessigere Beanspruchung des Duebels erreicht, eine Masseeinsparung erzielt und der Aufwand zum Bohren der Duebelloecher vermindert.The invention relates to a Spreizduebel that is used in structural parts made of concrete, reinforced concrete, masonry, natural or artificial stone of appropriate strength for anchoring objects. The main deficiency of the previously used Spreizduebel for o. G. The purpose of the application is that due to unfavorable design of the dowel by notch effect, the strength properties of the dowel are used inadequately. By reducing the number of molds a gleichmaessigere stress on the dowel is achieved, achieved a mass saving and reduces the effort to drill the Duebelloecher.

Description

Ausführungsbeispielembodiment

Die Erfindung soll an nachfolgendem Ausführungsbeispiel näher erläutert werden.The invention will be explained in more detail in the following embodiment.

In Figur 1 ist der Querschnitt des oben beschriebenen Spreizdübels dargestellt. Das Gewinde 1 ist auf dem Schaft 2 durch Kaltumformung aufgerollt. Der zylindrische Teil 3 hat zur Herabsetzung der Kerbwirkung zum Schaft 1 den Übergangsradius R1. Der zylindrische Teil (Sitz des Spreizringes im Fertigungs- und Montagezustand) geht mit dem Übergangsradius R 2 in den Spreizkonus 4 über. Der geschlitzte Spreizring 5 wird auf den zylinderischen Teil 3 aufgerollt. Die Abwicklung des Spreizringes 5 ist in Figur 2 dargestellt. Die Zacken 5a, der sich entgegen der Belastungsrichtung verjüngende Querschnitt 5 b oder der Biegeradius 5c dienen der leichteren Spreizung auf dem Konus. Der Dübel wird in bekannter Weise in ein in Bauwerksteile 6 eingebrachtes Bohrloch 7, dessen Durchmesser dem Flankendurchmesser des Gewindes entspricht, eingesetzt. Beim Anziehen der Mutter 8, die sich auf der Unterlegscheibe 9 und dem zu befestigenden Gegenstand 10 abstützt, gleiten die Konen in die Spreizringe 5, weiten diese auf, wodurch eine feste Klemmverbindung Dübel-Spreizring-Bauwerksteil entsteht. Für einen Spreizdübel aus korrosionsbeständigem austenitischem Stahl der Stahlmarke X8CrNiMo 18.11 der Abmessung M8 χ 80mm wurde durch Anwendung eines Abrundungsradius von 1 mm an den oben geschriebenen Übergangsstellen eine Erhöhung der Bruchfestigkeit um 18% erreicht. Durch Anwendung der Kaltumformung zur Gewindeherstellung und der dadurch erreichten Durchmesserreduzierung des Schaftquerschnittes auf den Flankendurchmesser des Gewindes tritt eine Materialeinsparung von 22% ein. Die Formzahl bei Zugbeanspruchung verringert sich durch die oben genannten Maßnahmen von 3,08 auf 1,52.In Figure 1, the cross section of the expansion anchor described above is shown. The thread 1 is rolled up on the shaft 2 by cold forming. The cylindrical part 3 has to reduce the notch effect to the shaft 1, the transition radius R1. The cylindrical part (seat of the expansion ring in the manufacturing and assembly state) merges with the transition radius R 2 in the expansion cone 4. The slotted spreader 5 is rolled up on the cylindrical part 3. The development of the expansion ring 5 is shown in Figure 2. The serrations 5 a, the cross-section 5 b, which tapers counter to the loading direction, or the bending radius 5 c serve for easier spreading on the cone. The anchor is inserted in a known manner in a built-in structural parts 6 borehole 7, whose diameter corresponds to the pitch diameter of the thread. When tightening the nut 8, which is supported on the washer 9 and the object 10 to be fastened, the cones slide into the expansion rings 5, widening them, whereby a firm clamping connection dowel spreader-structure part is created. For an expansion anchor made of corrosion-resistant austenitic steel of the steel brand X8CrNiMo 18.11 of dimension M8 χ 80mm, an increase of the breaking strength of 18% was achieved by applying a radius of 1 mm at the above-described crossing points. By applying the cold forming for threading and thereby achieved diameter reduction of the shank cross-section on the pitch diameter of the thread, a material saving of 22% occurs. The tensile form number decreases from 3.08 to 1.52 due to the above measures.

Claims

1. Expansion dowel for non-positive anchoring of objects in building parts made of concrete, reinforced concrete, masonry and analog solid building materials, such. B. natural and artificial stone, characterized in that the transitions to the individual functional surfaces of the dowel, shank - seat of the expansion ring - cylindrical guide - expansion cone are connected by rounding radii and the ratio of shaft diameter to diameter expansion ring 1.15 to 1.35 ,

2. Expansion dowel according to item 1, characterized in that the expansion rings are bevelled, rounded or arranged with an additional bending radius in the longitudinal direction or with serrated projections in the cone direction.

3. Expansion dowel according to item 1 and 2, characterized in that one or more expansion rings and Aufgleitkonen are arranged.

For this 1 page drawings

Field of application of the invention

The invention relates to an expansion anchor which is used in structural parts of concrete or reinforced concrete (at least BK20), masonry (at least HZ250 / MGIII) or correspondingly hard natural stone or artificial stone for anchoring objects (for example curtain walls).

Characteristic of the known technical solutions

The previously known expansion dowel have the disadvantage that due to their design not suitable for stressing the strength values of the dowel material are only insufficiently utilized by notch effect. The previously known structural design of the seat of the expansion causes under load that this represents the vulnerable cross-section. The sharp-edged transitions from the shaft to the cylindrical guide part, which is also the seat for the spreader in the manufacturing and assembly state, causes local stress concentrations in the load of the dowel, so that the breakage of the dowel always takes place at this sharp-edged transition.

Thus, the DDR-PS 202338 describes a dowel, which requires a lot of effort in the production and insertion into the building parts. These and other constructions are very material and costly, since in some cases, where a long-term corrosion resistance is required, stainless steels must be used.

Object of the invention

The aim of the invention is to develop a Spreizdübel that guarantees a lower material consumption and reduces the effort when inserting into the building parts of concrete or reinforced concrete, masonry or natural or artificial stone.

Explanation of the essence of the invention

The invention has for its object to provide an expansion anchor, which guarantees higher strength values with improved material utilization while maintaining the positive properties of known dowel designs. According to the invention the object is achieved in that the transitions to the individual functional surfaces of the dowel (mounting thread - shaft - seat of the spreader ring in the manufacturing and assembly state - expansion cone - cylindrical guide) are designed to be homogeneous. The seat of the expansion ring in the manufacturing and assembly state is connected by rounding radii with the shank or the cylindrical guide part whose diameter is reduced, and the expansion cone. This training ensures that the shape number according to TGL 19340/04, p. 5, does not exceed the value of 1.60 in the case of tensile stress. In this case, a ratio of the shaft diameter of the Spreizringsitzes in the manufacturing and assembly state of 1.15 to 1.35 is observed.

The expansion dowel is inserted into a borehole whose diameter corresponds to the pitch diameter of the fastening thread of the dowel. This is at the same time the diameter of the cylindrical dowel shaft. When tightening the nut on the mounting thread of the spreader slides on the expansion cone and clamps after slight slippage in the well. This process can be supported or accelerated by beads on the expansion ring, by a bending of the expansion ring, a tapered cross-section or serrated projections against the loading direction. To ensure a secure adhesive bond and to increase safety, the dowel is preferably equipped with more than one spreader in heterogeneous components.

The spreader ring must not slide over the rounding radius on insertion of the dowel into the drilled hole on the shaft, which is to be ensured by clean cut edges on the spreader ring and corresponding design of the rounding radius at the transition from the dowel shaft to the cylindrical and conical part of the dowel for the Spreizringsitz.