IE48537B1

IE48537B1 - An anchoring bolt

Info

Publication number: IE48537B1
Application number: IE1487/79A
Authority: IE
Original assignee: Hainke Volker
Priority date: 1978-08-04
Filing date: 1979-08-08
Publication date: 1985-02-20
Also published as: GR64886B; DK328979A; DE2834241A1; ES245000Y; NO792572L; IE791487L; NO150650C; DE2961138D1; PT70021A; ES245000U; ATE266T1; NO150650B; EP0008085A1; EP0008085B1

Abstract

1. An anchoring bolt to be anchored in a hole, having a screw for screwing up the bolt tight, said screw having a threaded part and a coned head part becoming thicker in a direction away from the threaded part, and furthermore a sleeve with a female-threaded hole next to an anchoring part able to undergo expansion in sectors, characterized in that the sleeve (10) has a many sided cross-section and in the middles of such sides has bursting lines (22) which are of decreased strength and are parallel to the anchoring bolt's axis.

Description

The invention relates to a foundation holt for anchorage in a bore, with a tension rod which exhibits a screwthreaded cross-section and a head section conically enlarged from the latter, also having a sleeve with a female screwthreaded section and an adjacent sectorally spreadable anchorage section.

Foxuidation bolts of this type are known. They exhibit a sleeve, the anchorage section of which is constituted by a hollow cylinder of circular cross10 section provided with axially parallel slits. The screwthreaded section of the tension rod is screwed into the female screwthread of the sleeve from the side of the anchorage section, and the two are introduced as a unit into a bore. The tension rod. is then further rotated until it urges the spreadable anchorage cross-section of the sleeve apart by its conical head section and thus anchors the sleeve in the surrounding material, such as timber, chipboards or concrete.

The disadvantage of the conventional foundation holt mentioned, lies in the fact that there is a danger that when the tension rod. is tightened the sleeve may follow its rotation in the bore, so that the sleeve cannot be spread and therefore does not become anchored.

Attempts have now been made to provide the surface of the sleeve with a corrugation, but even this corrugation has not always led to the desired success. - 3 Furthermore, a sleeve of circular cross-section has the disadvantage that the spread circular arcuate segments exhibit sharp corners and edges for anchorage in the material only to a small degree.

It is therefore the underlying aim of the invention to construct a foundation bolt of the type initially defined in such a way that it permits an immediate, secure and durable anchorage in the material.

The invention accordingly provides an anchoring bolt to be anchored in a hole, having a screw for screwing up the bolt tight, said screw having a threaded part and a coned head part becoming thicker in a direction away from the threaded part, and furthermore a sleeve with a femalethreaded hole next to an anchoring part able to undergo expansion in sectors, characterised in that the sleeve has a many-sided cross-section and in the middles of such sides has bursting lines which are of decreased strength and are parallel to the anchoring bolt's axis.

The polygonal, more particularly hexagonal, crosssection of the sleeve reliably prevents the sleeve from following the rotation when the tension rod is tensioned. Furthermore, the polygonal cross-sectional shape produces a number of additional sharp corners on the spreadable side of the sleeve which facilitate entry into the material and locking in the material.

According to a preferred embodiment the sleeve exhibits in its spreadable anchorage cross-section, starting from the screwthreaded section, a flat conical enlargement which co-operates with the conical head section of the tension rod. The two conical surfaces together permit a soft uniform spreading of the sleeve by a small exertion of force, so that in this way also the danger of the sleeve follcwing the rotation - 4 of the tension rod or being withdrawn before anchorage is achieved, is reduced.

Grooves, which may have a vee-shaped crosssection, are preferably provided in the axially parallel median lines of the surfaces of the polygon.

It is convenient to co-ordinate the depth of the grooves and the course of the conical enlargement in the interior of the anchorage section of the sleeve mutually so that the two converge substantially at the free edge of the sleeve, so that an immediate tearing open and spreading of the sleeve is possible there.

The tension rod, which is known as such, may be of such construction that the conically enlarged head section constitutes a smooth cylindrical shank, at the end of which an enlargement in the form of a slotscrew or female hexagonal screw head is provided.

The sleeve may consist of various plastics or metals and may also more particularly be produced, as an aluminium injection die-casting.

Further particulars of the invention will emerge from the subordinate claims.

Preferred exemplary embodiments of the invention are explained more fully hereinbelow with reference to the accompanying drawing, wherein: Fig. 1 shows a partial section of an arrangement of tension rod and sleeve before assembly; Fig. 2 is a larger scale elevation of the sleeve along the line 2-2 in Fig. 1; Fig. J is a partial section of the foundation bolt during tensioning; and Fig. 4 is an elevation along the line 4-4 in Fig. 3.

In Fig. 1, a sleeve is designated 10 and a tension rod 12. The sleeve is constituted, in the longitudinal direction, by two sections, which are designated as a female screwthreaded section 14 on the left-hand side in Fig. 1 and as a spreadable anchorage section 16 on the right-hand side in Fig. 1. The female screwthreaded section 14 exhibits a concentric axial bore 18 with female screwthread. The anchorage section 16 is provided internally with a bore 20 which widens conically towards the free end to the right in Fig. 1.

The cone angle of this bore 20 is comparatively small and may be e.g., 3 to 4° referred to the longitudinal median line of the sleeve. As Fig. 2 clearly shows, the circumference of the sleeve 10 is of hexagonal cross-section. Grooves 22, which may have e.g., a vee20 shaped cross-section, are provided in the longitudinal median lines of the six planes bounding the outwards surfaces of the sleeve.

The enlargement of the bore 20 and the depth of ' the grooves 22 are mutually co-ordinated in such a way that they converge substantially at the right-hand end of the sleeve in Fig. 1, or at least are separated by a very slight thickness of material which can immediately be interrupted.

The tension rod shown on the right-hand, side in Fig. 4 comprises a screwthreaded section 24- provided with a male screwthread and a frustoconical head section 26 adjoining the same. The male screwthread of the screwthreaded section 24- corresponds to the female screwthread of the bore 48. The frustoconical head section 26 need not necessarily exhibit a precise conical surface, but may also be bevelled or rounded in a different manner. The head section 26 in the example illustrated merges into a cylindrical shank 28 of any desired length and a head 30 adjoining the latter for the application of a screwdriver or female hexagon key. However, other elements which permit a rotation and a bracing of the tension rod 42 to the left in Fig. 4 may be provided instead of the shank and of the head 30.

During the assembly of the foundation bolt according to the invention, the screwthreaded section 24- is first of all passed through the anchorage section 46 and screwed into the bore 48, until e.g., the conical head section 42 is loosely in contact against the right-hand end of the sleeve. In this position the sleeve and the tension rod are introduced as a unit into a bore, which may be e.g., a bore in a 25 concrete wall or in components made of timber or chipboards. Box-shaped furniture items may be assembled e.g., making blind holes in a board from each of its edges, and drilling holes with a countersink for the head 30 in associated positions of rectangularly - 7 adjacent boards. These possibilities of assembly are known per se and will therefore not be explained in detail.

The unit comprising sleeve 10 and tension rod 12 is introduced into the hole until the head JO abuts against a suitable stop, e.g., the bottom of a sunk hole. When the tension rod 12 is further rotated in this position the sleeve 10 is attracted due to the screwthread engagement between the screwthreaded section 24 and the bore 18 and simultaneously spread, as shown in Fig. 3. During this spreading the anchorage section 16 tears open in the region of the grooves 22 (Fig. 2) into individual segments J2 (Fig. 2).

These segments penetrate increasingly into the material I5 of the adjacent wall of the bore, so that the sleeve becomes anchored in the bore. The position of Fig. 4 is then substantially obtained.

The cross-sectional shape of the sleeve 10 according to the invention not only has the advantage that a corotation of the sleeve during the tensioning operation is excluded. On the contrary, Fig. 4 clearly shows that the individual segments 32 constitute a larger number of sharp corners than is the case say, of cylindrical spreadable sleeves. Said sharp corners facilitate the penetration into the material of the bore wall and hence the anchorage of the sleeve.

The foundation bolt according to the invention makes possible, for example, a corner joint of box48537 _ 8 _ shaped, furniture items without fitting parts being visible on the external surface of the individual boards, with the exception of the head 30 let into a sunk bore, which can however if desired be used as a decorative element.

After the anchorage the sleeve Ί0 attains a fixed seat in the associated bore, which is still retained if the tension rod 42 is unscrewed in order to release the joint and possibly screwed back in again after10 wards

Claims

1. CLAIMS :1. An anchoring bolt to be anchored in a hole, having a screw for screwing up the bolt tight, said screw having a threaded part and a coned head part becoming thicker in a direction away from the threaded part, and furthermore a sleeve with a female-threaded hole next to an anchoring part able to undergo expansion in sectors, characterised in that the sleeve has a many-sided cross-section and in the middles of such sides has bursting lines which are of decreased strength and are parallel to the anchoring bolt's axis.

2. An anchoring bolt as claimed in claim 1, characterised in that the sleeve becomes wider inside with a small cone angle, starting from the part with the female thread.

3. An anchoring bolt as claimed in claim 1 or claim 2, characterised in that the cross-section of the sleeve is six-sided.

4. An anchoring bolt as claimed in any one of claims 1 to 3, characterised in that the less strong lines of bursting are formed by grooves generally of V-like cross-section.

5. An anchoring bolt as claimed in claim 4, characterised by the grooves running along the full length of the sleeve.

6. An anchoring bolt as claimed in claim 2 and claim 5, characterised in that the coned part inside the sleeve and the depth of the grooves are such that they come together generally at the free end of the bursting anchoring part of the sleeve.

7. An anchoring bolt as claimed in any one of claims 1 to 6, characterised in that the sleeve is an aluminium injection casting.

8. An anchoring bolt as claimed in claim 1, substantially as herein described.