IE41664B1 - Expansible anchor - Google Patents

Abstract

1513028 Stud fastenings HILTI AG 13 Aug 1975 [2 Sept 1974] 33669/75 Heading E2B [Also in Division F2] An anchor has an expansible sleeve I with a non-circular internal profile 1a and slots 3. The sleeve 1 is engaged by an expansion element 4 rotation of which causes part 4a (which also has a non-circular cross section) to expand the sleeve. Slots 3 in the sleeve 1 allow the anchor to be assembled and the sleeve to expand and these slots may be inclined to the axis at least over part of their length. Abutments 2, 5 limit the axial movement of the sleeve and expansion element. In another embodiment (Fig. 10) the parts of the sleeve 8 are joined by a yoke 10 which acts as an abutment in contact with the element 4a. The collar 5 may in this case serve to locate the depth of the anchor by contact with surface 11a.

Description

This invention relates to an expansible anchor, more especially a suspension anchor, comprising an expansible sleeve having elongate slots arranged in an expansible region thereof and an expansion element which is arranged in the expansible sleeve, the inner surface of the sleeve and the outer surface of the expansion element being so contoured that cross-sections thereof, taken substantially perpendicular to the main axis of the sleeve, at least over a part of the length of the anchor, have confronting profiles which deviate from circular configuration, so enabling expansion of the sleeve to be achieved by twisting of the expansion element relative to the sleeve.

Varied suspension elements are already known for the suspension of ceilings, facings, frameworks, pipes, cables and the like. Since all such elements are generally used in substantial quantities in building structures it is desirable that the installation thereof should be capable of being effected with the least possible expenditure of time and without the use of special tools. 2.

Usually the known suspension elements are in the form of an expansible dowel comprising an expansible sleeve and an expansion element. Thus for example, a dowel-like suspension element is known whose expansion element comprises a plate-like component which is shaped in a corrugated manner and on which a slotted expansible sleeve is mounted so as to be displaceable. The corrugated outer contour widens towards the insertion end or front end (i.e. the end which is first inserted into the receiving material) so that axial displacement of the expansible sleeve relative to the expansion element, by hammering-in, results in radial expansion of the expansible sleeve.

A further known suspension element comprises an expansion element having a circular cross-section and a slotted expansible sleeve, of circular-ring-shaped cross-section, in which the expansion element, which has one end widening conically towards the front-end, is mounted so as to be displaceable. In use of this element, upon force being applied to tend to with15 draw the expansion element from the reception bore in the receiving material, radial widening of the expansible sleeve occurs, so that anchorage in the reception bore is achieved.

The known element first mentioned above has the disadvantage that the necessary axial displacement of the expansible sleeve relative to the expansion element introduced into the reception bore can be effected only in an extremely time-consuming manner and with the aid of an additional tool, for example a hammer. This makes it virtually impossible to effect premounting of further elements, such as height adjustment members or spacers, suspension hooks or the like, which cooperate with the suspension element.

On the contrary, it is necessary for these elements to be mounted subsequently, which can be very arduous more especially where high locations are involved. 3.

The second above-mentioned known element has the disadvantage, where a succession thereof is being installed, that constant suspension heights cannot be achieved. This is because the sudden drawingoutward, necessary for expanding the expansible sleeve, of the expansion element outwards of the reception bore, results in an undefined eventual depth of insertion of the element, dependent on the nature of the bore hole, so that when installing a series of the elements, different spacings of the suspension points from the receiving material arise. Thus, time-consuming subsequent adjustment of the further parts to be connected to the suspension elements becomes necessary. In addition to this, there is the substantial disadvantage that the element is expanded only under load and is merely able to absorb loads in one and the same loading direction. Consequently vibrations or alternating loads can result in the expansible sleeve contracting, so that the anchorage of the element is completely lost.

The expansion principles, known from other fields of use, in relation to dowels cannot be transferred to the field of interest here.

Thus, for example, in the case of a dowel that is expanded by twisting of the expansion element relative to the expansible sleeve, it is disadvantageous that such dowels have to have an axial guide between the expansion element and the expansible sleeve. Thus there exists a positive axial dependence between the expansible sleeve and the expansion element, so that, under the tensile loads which occur practically exclusively in the case of suspensions, re-expansion of the sleeve cannot be effected, so that the entire dowel element, including the expansible sleeve, can be torn out of its reception bore. Also alternating loads occurring in the longitudinal direction of the dowel have a negative effect on such an expanding dowel, since the expansible sleeve has to move in correspondence with the expanding element by reason of the positive connection therebetween. 4.

The problem underlying the present invention is to provide an expansible anchor which is especially suitable for suspensions and which can be set without the use of special tools and which even in the unloaded condition provides adequate anchorage which increases with increasing load.

To solve this problem, the present invention provides an expansible anchor, more especially a suspension anchor, comprising an expansible sleeve for insertion, insertion end first, into a bore-hole in receiving material, said sleeve having elongate slots in an expansible region thereof, and an expansion element which is arranged in the expansible sleeve, and which protrudes therefrom, at the end remote from the insertion end, by a head by means of which the said expansion element can be twisted, the inner surface of the sleeve and the outer surface of the expansion element being so contoured that cross sections thereof, taken substantially perpendicular to the main axis of the sleeve, at least over a part of the length of the anchor, have confronting profiles which deviate from circular configuration, so enabling expansion of the sleeve to be achieved by twisting of the expansion element relative to the sleeve, at least a part of the expansion element, and, optionally at least a part of the opening through the expansible sleeve, widening over at least a part of the length of the anchor towards the insertion end of the anchor, so that withdrawing force, applied to the expansion element by means of the head to tend to withdraw it from the sleeve, causes sleeve expansion.

The profiles, differing from circular or annular configuration, of the expansible sleeve and of the expansion element, enable the expansible sleeve to be expanded by twisting of the expansion element relative to the expansible sleeve. Because of the widening of the expansion element and/ or the opening through the expansible sleeve, towards the insertion end of the anchor, any loading which tends to cause withdrawal of the expansion element from the expansible sleeve, in the axial direction, also results in additional expansion of the expansible sleeve.

. The profiles, differing from circular or annular configuration, of the inner contour of the expansible sleeve, and of the expansion element, can be designed at will. The contour of tbe expansion element can, by way of example, be such as to provide a non-circular crosssectional profile, e.g. resembling a cam, and the inner contour of the expansible sleeve can be such as to provide a cross-sectional profile which approximates to a spiral. Likewise, the contour of the expansion element and the inner contour of the expansible sleeve can provide cross-sectional profiles which are elliptical or oval to ensure that expansion occurs upon twisting of the parts relative to one another.

Where the profiles are shaped as polygons having rounded corners, uniform load distribution is achieved over the entire expansion region. A profile in which the outer contour of the expansion element is elliptical has proved to be particularly advantageous. In this connection, the term elliptical'' is not to be understood mathematically in the strictest sense, but is to include a profile which has only two regions which symmetrically overlap the basic circular cross section in one plane and which can be produced in a particularly economical manner. This ellipse-like oiiter contour of the expansion element can cooperate either with a cross-sectional contour of the expansible sleeve which is likewise profiled in ellipse-like manner or with two eccentric part-circular profiles, which are staggered and each comprise a semicircle, of the inner contour of the expansible sleeve. In the first mentioned case where the expansion element's profile is elliptical an angle of rotation of about 90° is available for expansion, and in the case where the part circular profiles are provided, an angle of rotation of about 180° is available for such expansion.

The widening of the opening through the expansible sleeve and of the expansion element can be effected in various ways. On the one hand, it is possible to design only the outer contour of the expansion element 6. so that it widens, and on the outer hand it is possible to design only the contour of the opening through the expansible sleeve so that it widens towards the front end.

It is, however, convenient to design both the opening through the expansible sleeve and the outer contour of the expansion element so as to widen substantially uniformly towards the insertion end of the anchor. The widening can be arranged at any desired location longitudinally of the anchor. Preferably, however, at least a part of the outer contour of the expansion element and/or at least a part of the contour of the opening through the expansible sleeve widen substantially over the entire length of their confronting profiles. Of course, in the case of this combination of profiles and widening, it is possible, substantially within the same region of the anchor, to widen only the inner contour of the expansible sleeve, to widen only the outer contour of the expansion element, or to use a combined widening on both parts. In this connection the supplementary expansion of the anchor desired to arise under load by reason of displacement of the expansion element relative to the expansible sleeve is effectively achieved when those regions of the outer contour of the expansion element and, optionally of the inner contour of the expansible sleeve widen towards the insertion end of the anchor and are in mutual engagement with each other after the expansion brought about by twisting the expansion element.

These regions are naturally the regions which protrude beyond the basic circular cross-section of the profiles of the outer contour of the expansion element and the regions which lie within the basic circular crosssection of the profile of the inner contour of the expansible sleeve.

In accordance with a further proposal of the invention, the elongate slots of the expansible sleeve extend, at least over a part of their lengths, at an angle inclined relative to the main axis of the anchor. This 7. slot arrangement guarantees that the regions, projecting from the basic circular cross-section of the profile of the outer contour, of the expansion element, which regions widen towards the insertion end or front end of the anchor, bring about the desired further expansion of the anchor when under load, even if there should be inadequate expansion by twisting of the expansion element so that it does not engage completely into the slots of the expansible sleeve, and guarantees adequate expansion of the sleeve. More especially where there is provided, substantially in the same longitudinal region of the anchor, a combination of profiling and widening for receiving the axial component of force produced by the twisting of the expansion element and directed towards the insertion end of the anchor, advantageously the anchor has an abutment for limiting the axial displaceability of the expansion element relative to the expansible sleeve. Where such an abutment is present, the component directed towards the insertion end of the anchor is utilised for radial expansion of the expansible sleeve. In this way, also the possibility is afforded of conceiving a quick-clamping element which can be used for other purposes and is not exclusively suitable for suspensions. In the case of such a rapid-clamping element the end of the expansion element remote from the insertion end can, for example have, instead of a head with suspension facilities, a head which is then to be provided with formations for the application thereto of tools for imparting rotary movement thereto. Such a rapid-clamping element can, for example, be used for fastening facings, copings, cladding or the like, in which case, the head then fulfils a supporting function.

; In accordance with a development of the invention, the abutment can be designed as a collar which is arranged in the region of the expansion element remote from the insertion end and which projects outwardly beyond the inner contour of the expansible sleeve. Instead of such collar, in accordance with an alternative proposal of the invention the abutment can be designed, in the region of the expansible sleeve closest the insertion end 8. of the expansion element, as a web or crosspiece which protrudes inwardly beyond the inner contour of the expansible sleeve. Such an abutment arranged on the expanding sleeve may serve to prevent any substantial axial displacement of the sleeve which would otherwise occur as a result of the axial component of force produced by twisting the expansion element after compensation of the axial play inside the expansible sleeve, so that the entire twisting angle available can be used exclusively for expansion of the expansible sleeve. This is of significance more especially for overcoming large borehole tolerances and for fastenings in relatively soft receiving materials.

The use of the expansible anchor in accordance with the present invention is significantly facilitated, both for suspensions and for other purposes, if stop means is provided for limiting the depth of insertion, said stop means being disposed so that upon introduction of the anchor into a borehole it comes to bear against the surface of the receiving material. For this purpose the expansible sleeve conveniently has at its rearward end, stop means radially overhanging the outer contour. These stop means, may for example, be designed in the form of a flange connected to the expansible sleeve. In accordance with a further proposal of the invention the possibility also exists of providing the expansion element in the rearward region with stop means, projecting radially beyond the outer contour of the expansible sleeve, for achieving the depth limitation. A collar which is arranged on the expansion element and whose outside diameter overlaps the outer contour of the expansible sleeve is, for example, also suitable as the stop means.

The invention will be described further, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a sectional elevation of an expansible sleeve forming part of an anchor in accordance with the invention; 9.

Fig. 2 is a section taken along the line II-II of Fig. 1; • Fig. 3 is a plan view of the expansible sleeve of Figs. and 2; Fig. 4 is an elevation of an expansion element which together with the expansible sleeve of Figs. 1, 2 and 3 forms the said expansible anchor according to the invention; Fig. 5 is a side view of the expansion element of Fig. 4; Fig. 6 is a plan view of the expansion element of Figs. 4 and 5; Fig. 7 is a part-sectional elevation illustrating an expansible anchor conforming to the invention composed of the expansible sleeve of Figs. 1 to 3 and the expansion element of Figs. 4 to 6, said anchor being shown in position in a reception bore but with the expansible sleeve in the nonexpanded condition; Fig. 8 is a sectional elevation of a second form of expansible sleeve which forms part of a second embodiment of the expansible anchor of the invention; Fig. 9 is a side view of the expansible sleeve of Fig. 8; and Fig. 10 is a view similar to Fig. 7 but illustrating an expansible anchor which comprises the expansible sleeve of Figs. 8 and 9 in combination with the expansion element of Figs. 4 to 6.

Illustrated in Figs. I to 3 is an expansible sleeve which is designated as a whole by the reference numeral 1. Inner contour 1a_ of the expansible sleeve 1 has, as is more especially evident from Fig. 3, an ellipselike profile which widens towards front end 1J> of the sleeve. Rearward end lc of the sleeve has a stop means, projecting radially beyond the outer contour Id, in the form of a flange 2. In the longitudinal direction thereof, the expansible sleeve 1 has two slots 3 of which one also penetrates the flange 2. The . number of slots 3, which in the present example is two, can be selected at will and be adapted to the purpose to which the respective anchor is to be put.

Figs. 4 to 6 illustrate an expansion element which is designated as a whole by the numeral 4 and serves for example as a suspension element. As shown more especially in Fig. 6, expanding part 4^ of the expansion element 4 has an ellipse-like cross-section contour 4b, of which widens towards the front end. The rearward end of the expanding part 4a is bounded by a collar 5. Connecting rearwardly to the collar 5, by way of example, is an eye-shaped part 6 having a bore 7 by which elements (not shown), such as components to be suspended, can be connected to the expansion element 4.

Fig. 7 shows an expansible anchor, composed of the expansion element 4 and the expansible sleeve 1, in the non-expanded condition just after having inserted into a bore 11 in receiving material lljx Assembly together of expansion element 4 and the expansible sleeve 1 is facilitated by the presence of the slot 3 which penetrates the flange 2.

The expansible anchor, inserted into the bore 11 as shown in Fig. 7, is anchored in the bore 11 as follows. Firstly care is taken to ensure that the anchor has been inserted into the bore 11 until the flange 2 abuts against outer surface 1¼ of the receiving material lib. Then the expansion element 4 is rotated in either direction about its longitudinal axis through an angle of 90°. By virtue of the inner contour la^, widening towards the insertion end, a force component arises which endeavours to drive the expansion element 4 inwards towards the bottom of the reception bore 11. The collar 5 of the expansion element 4, abutting the expansible sleeve 1, opposes this force component so that the expanding sleeve 1 preforce experiences a widening and in this way anchorage in the reception bore 11 is achieved. Upon loading the expansible anchor by application of force to the expansion element 11. relative axial movement occurs between the expansion element 4 and the expansible sleeve 1 which, by virtue of the presence of the widening contours la, 4b, results in further expansion of the expansible sleeve 1.

Figs. 8 to 9 illustrate an alternative embodiment of 5 expansible sleeve, which is designated as a whole by the reference numeral 8.

Inner contour 8a_ of .the expansible sleeve 8 also has a profiling which is designed, by way of example, substantially to ellipse-like form and which widens towards front end 8Jo of the sleeve 8. Furthermore, the expansible sleeve 8 has slots 9 which are inclined relative to the axis of the sleeve 8.

Connecting to the front end of the expansible sleeve 8 is a web or yoke 10, which bridges across the sleeve 8 at a spacing therefrom to constitute an abutment.

Fig. 10 illustrates an expansible anchor consisting of an expansion element in accordance with Figs. 4 to 6 and an expansible sleeve in accordance with Figs. 8 and 9. Fig. 10 shows how axially-directed force component occurring upon insertion of the anchor is absorbed by the abutment which is carried by the expansible sleeve 8 and which is provided by the yoke . Thus the provision of an abutment on the expansion element 4 is superfluous. The collar 5 of the expansion element 4 serves, in this case, merely for depth limitation of the expansible anchor, at the surface ll£ of the receiving material 1W, so that the stop flange 2 provided on the expansible sleeve of Figs. 1 to 3 can be omitted in the sleeve 8.

Upon widening of the expansible sleeve 8, the abutment provided by the yoke 10 is displaced, as a function of the widening, contrary to the direction of introduction of the expansible anchor. In this way one achieves a length adaptation which is particularly advantageous especially in the case of large borehole tolerances or soft receiving material, so that in these cases optimum expansion, by complete utilisation of the angle of rotation, is achieved.

Claims (9)

1. An expansible anchor, more especially a suspension anchor, comprising an expansible sleeve for insertion, insertion end first, into a bore hole in receiving material, said sleeve having elongate slots in 5 an expansible region thereof, and an expansion element which is arranged in the expansible sleeve, and which protrudes therefrom at the end remote from the insertion end, by a head by means of which the said expansion element can be twisted, the inner surface of the sleeve and the outer surface of the expansion element being so contoured that cross sections thereof, taken sub10 stantially perpendicular to the main axis of the sleeve, at least over a part of the length of the anchor, have confronting profiles which deviate from circular configuration, so enabling expansion of the sleeve to be achieved by twisting of the expansion element relative to the sleeve, at least a part of the expansion element, and, optionally at least a part of the opening through 15 the expansible sleeve, widening over at least a part of the length of the anchor towards the insertion end of the anchor, so that withdrawing force, applied to the expansion element by means of the head to tend to withdraw it from the sleeve, causes sleeve expansion.

2. An expansible anchor as claimed in Claim 1, characterised in that the expansion element and the expansible sleeve widen over substantially the entire lengths of their confronting profiles.

3. An expansible anchor as claimed in Claim 1 or 2 characterised in that the elongate slots of the expansible sleeve are inclined relative to the axis of the anchor at least over part of their length. 25

4. An expansible anchor as claimed in any preceding Claim characterised in that an abutment is provided for limiting the axial displaceability of the expansion element relative to the expansible sleeve. 13.

5. An expansible anchor as claimed in Claim 4, characterised in that the abutment is designed as a collar which outwardly overlaps the inner contour of the expansible sleeve.

6. An expansible anchor as claimed in Claim 4, characterised 5 in that the abutment comprises a web or yoke which projects inwardly relative to the inner contour of the expansible sleeve.

7. An expansible anchor as claimed in any preceding Claim characterised in that the expansible sleeve has stop means for limiting its depth of insertion. <1 10

8. An expansible anchor as claimed in any of Claims 1 to 6 characterised in that the expansion element has stop means which radially overlaps the outer contour of the expansible sleeve, for limiting its depth of insertion.

9. An expansible anchor substantially as hereinbefore 15 described with reference to and as illustrated in Figs. 1 to 7, or in Figs. 4, 5, 6, 8, 9, and 10, of the accompanying drawings.