CA1050793A - Expansion anchor having an elliptically shaped expanding element - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

An expansion anchor for dependently supporting an object consists of a sleeve having an axially extending passage and an axially extending expansion element axially and rotatably displaceably within the sleeve passage to provide the desired expanding effect. Both the outer surface of the expanding element and the inner surface of the sleeve forming the passage have a transverse cross section which is elliptical or varies from a circular shape. Each of the sleeve and the expanding element has a leading end and a trailing end and a portion of the inner surface of the sleeve and the outer surface of the expanding element taper outwardly in the direction toward their leading ends.

Description

~1~50~931 The present invention is directed to an expansion anchor, particularly of the type for dependently supporting an object, which consists of an expanding sleeve and an expanding element axially and rota,tably displaceable within ~he sleeve~
The inner surface of thq sleeve and the outer surface of the expanding element in se~tion extending transversely of the axis of the expansion anchor have a shape which varies from a circular shape so that the sleev~, can be expanded by turning or rotating the expanding e}ement a~out its axis within the sleeve.
A variety of ha~ging elements are known for dependently supporting dropped ceili!ngs, panelling, scaffolding, pipes and the like. 5ince such h~nging elements are normally used in great numbers and in a series arrangement, it must be possible to set the elements with a minimum of time expended and without any special tools~ Such hanging el~ments are usually expansion anchors consisting of expanding sleeves and expanding elements positionable within the sleeves. Fo~ example, an anchor type hanging element is known whose expandin~ element consists of an undulated plate with respect to which a slotted expanding sleeve is displaceably mounted. The outer shape of the plate widens towards its leading end so that an axial displacement of the expanding sleeve relative to the expanding element by driving in results in a radial expansion of the sleeveO
Another known h~nging element consists of an expanding element which is circul~r in cross section and a slotted expanding sleeve of annular cross section. The expanding element widens in a corlical manner tow~rd its leading end and is displaceably mounted within the slee~eO In such an anchor, the expanding sleeve is radially wide~ed by the expanding element being pulled out of a receiving bore in the receiving material, thereby ~1~
~ 1 --, ~L~S~3 anchoring the sleeve and, element in the receiving bore.
The first expansion element mentioned above has the disadvantage that the required axial displacement of the sleeve relative to the expanding element introduced into a receiving bore can be effected only in an extremely time-consuming manner and by means of an additional tool, for example, a hammer. The required expansion of the element makes any preliminary assembly of additional objects cooperating with the expansion element, '.
like vertical adjustment devices, hooks and the like~ impossible.
Such additional objects ,or devices must be subsequently assembled on the expansion element which can be difficult if the element is located at a great height.
The second eleme~t mentioned above has the disadvantage ' that the jerking or pull:ing action on the expanding element in displacing it out of the receiving bore, required for spreading the sleeve, due to an unl~efined depth of insertion into the hole and dependent on the typ~ of hole, results in constantly varyiny distances of support points on the expansion element from the receiving material. As a result, any subsequent adjustments of the support point can be time consuming in fitting other parts or objects to the element. Further, there is the considerable disadvantage that the element is expanded only under load and 3 can only absorb loads applied in the same direction. Consequently, vibrating or alternating loads have the effect that the expanding ~, sleeve contracts in the radial direction wi~h the anchoring effect being completely lost.
~he expansion principles used in other types of anchors cannot be utilized in anchors of this type,used as a depending support. For,examplel? a disadvantage of an expansion anchor 1.
which must be spread by turning the expanding element re}ative to ~.

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: 7 ~5~)793 the expanding sleeve is that the anchors must have an axial guide between the element and the sleeveO Further, there i~ a form fitting or locking dependence in ~le axial direction between the sleeve and the element, ~o that no after-spreading of ~he sleeve is possible under the tensile stresses which are applied when something is hung from the anchorp which has the result that the entire anchox, including the sleeve, can be torn out of the receiving bore~ Alternating loads applied in the axial direction of tha anchor would al~o ha-e 2 negative effect on such anchors, since the anchors would be moved in dependence on the expansion element, due to the axial form-locking characteristic.
Therefore, the primary object of the present invention, is to provide an expansion anchor which i~ particularly suit~ble for dependently supporting objects and the like and which can be set without any special tools. Further, the expansion anchor is adequately fixed in a receiving hole even in its unloaded state and any load applied to the anchor increases the anchoring or locking engagement within the hole. I

In accordance with the present invention, the problem of locking ox anchoring the sleeve within a receiving hole is solved by forming at least a portion of the outer surface of the expansion element and/or at least a portion of the surface of the passage in the sleeve containing the element so that its transverse cross-section shape is generally elliptical and widens toward the leading end of the anchor, that i~, the and which i~
first inserted into the receiving hole.
The variation of the transverse cross-sectional ~hape of the pa~sage in the sleeve or of the other surface o thc expanding elament from a circular ~urface to one ~hat i~
, :' i r ~D5~793 generally elliptical, has the result that the sleeve can be expanded by turning or rotating the expanding element about its axis relative to the sleeve. Since the complementary surfaces of the sleeve and the expanding element widen or diverage toward the leading end of the anchor, any load applied to the expanding element in its axiaL direction, tending to pull the elements out of the sleeve and out of the receiving hole, causes an additional spreading of the sleeve due to the tapered formation of one or both of the expanding 1 element and sleeve.
The transverse cross-sectional shape of the passage within the sleeve or of the outer surface of the expanding element which deviates ar varies from a circular form, can have any desired form. For example, the outer contour of the expanding element can be c~l~-shaped in cross section, while the inner surface of the sleeve can be formed as a spiral. Similarly, the outer shape of the expanding element and the shape of the inner surface of the sleeve can be formed in transverse cross section similar to a dou~le eccentric, so that points are formed on the transverse cross-sectional shapes which deviate or vary from a circular cross section and a spreading for expanding action is assured when the parts of the anchor are turned relative to one another.
If the transverse cross sections have the shape of an ; arcuate polygon with ro~ded off corners, a uniorm load distribution is achieved, particularly over the entire spreading range of the anchorO A particularly desirable cross-sectional shape for the expanding element is an elliptical shape. However, the term "elliptical" as used here is not intended in the strict mathematical sense rather it refers to such shapes which have I

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two region~ extending symmetrically from diclmetrically opposite sides of a base circle, such shapes can be produced in a particularly economical manner. Further, ~ elliptical shape refers to a shape where the radial dimension varies about the surface of the shape. An elliptical ~onfiquration on ~he outer ; surface of the expanding element can cooperate with a similarly elliptically shaped surface on the expanding sleeve or with a circular-eccentric surface within the sleeve staggered over half a cixcleq In the former case rotation of about 90 will provide the re~uisite expanding action while in the latter case an angle of rotation of about 180 will be required.
The widening for expanding action between the sleeve and the expanding element can be effected in various ways. It is possible, for example~ to provide only the expansion element with a shape widening toward its 1eading end or to make the inner surface of the sleeve so that only it widens toward the leading ~nd. However, t;o afford a uniform load distribution over , I
the expanding range of the anchor, it i~ advisable to shape both the inner surface of the sleeve and the outer surface of the expanding element, 80 that they widen in a uniform manner toward the leading end. With regard to the longitudinal or axial direction of the anchor, the wide~ing portions can be arranged at any point. However~ it is preferable if at least a part of the outer surface of ~he expanding element and at least a part of the -1 inner surface o the sleeve widen for an axial length to the ; leading end of the anchor. With this combination of the ellipti~al or non-circular shaping of the anchor parts and the widening of the parts toward the leading end, it i9 possible to provide the widening characteristic only on the inner surface of the sleeve or only on the outer surface of the expanding elem~nt or to : . ' _ 5 _ L~
' ' ~ ' ~ S6J ~913 provide it on both of the parts. The desired after-spreading of the anchor when load is applied by di~placing the expanding element axially relative to the sleeve, is particularly effective in those regions on ~he outer surface of the expanding elemen~ or on those surfaces on the inner ~urface on ~h~e sieeve which widen or taper outwardly toward the leading end of the anchor and which are in mutual engagement after the expanding action has been obtained by turning or rotating the expanding element relative to the sleeve. mese regions are naturally where the surfaces have the larger radial dimensions of the outer surface of the expanding element and which have the smaller radial dimensions of the inner ~urPace of the ~leeve.
Another feature of the invention is the provision of axially extending ~lots in the expanding sleeve wall which arQ
located in ~he portions of the sleeve which are in diverging relationship relative to the axis of the anchor ~oward its leading endO The arrangement of the ~lots en~ure~ that the region of the expanding element which exceed~ ~he minimum ; cross-sectional dimension of the outer surface of the element which effects the desired afterspreading of the anchor under load when they widen toward the front en~ of the anchor, do not fall completely into the slot8 of the sleeve, even with insufficient expansion in turning the expanding element, but ensure ~ufficient spreading of the sleeve~ Where the combination of ~he elliptical shaping and widening of the juxtaposed surface3 occur over the same axial extending region of the anchor, it is preferable to provide an abutment to ab~orb the component of force generated by the turning of the expanding element and direct~d : toward the leading end of the anchor for limiting the axial .
displacesbility of tho elelllent relativ~: to the sleeve. Suoh an ~ S~ 3 abutment utilizes the component of force directed toward the leading end of the anchor for effecting radial expansion of the sleeve. This arrangement affords the possibility of a quick-acting element which can be used for other applications than a ;~ dependent support. In such a quick-acting element~ the trailing end of the anchor can have a head which is provided with means for attaching tools for effecting xotation instead of an arrangement for dependently supporting objects. Such a quick-acting element can be used, for example~ for attaching paneling, and other wall coverings where the head of the anchor has a supporting function.
Another feature of the invention involves the provision of an abutment formed a~ a collar on the expanding element ; adjacent its trailing end and projecting radially outwardly of the expanding element. Alternatively, the abutment can be provided on the leading end of the sleeve consisting of a web member having ; two legs projecting from the leading end of the sleeve with a web ~` extending across the outer ends of the legs which provides the ; abutment surface. With such an abutment located on the expansion sleeve, it is po~sible to absorb the component of force directed toward the leading end of the anchor which occurs during expan~ion by turning the expanding element~ after balancing the axial play inside the sleeve, so that the entire angle of torque can be utilized exclusively for spreading the sleeve. This arxangement is particularly important in overcoming large borehole tolerance~ and also in securing the anchor in relativel~ soft receiving material.
The use of the expansion anchor embodying the present invention both for a dependent support and for other anchoring purpose~ is facilitated if stop means are provided for limiting ~ 30 the depth to which the anchor is inserted into a borehole in :

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j ~, ~5~ 3 the receiving material. Preferably, the sleeve is provided with a flange-like stop at its trailing end for limiting the depth to which it can be inserted into the borehole. In another feature of the invention, it is also possible to provide the expansion element near its trailing end with stop means for limiting the depth to which it can be inserted into the borehole.
-The stop formed on the expansion element also has a 1ange-like construction extending radially outwardly beyon~ the outer surface of the sleeve. A collar or a flange on the outer surface of the s 10 expansion element is adequate for ~his purpose if its outside diameter is greater than the outside diameter of the expanding sleeve at its trailing end.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosuxe. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there .
are illustrated and described preferred embodiments of the invention.
20IN_THE_DRAWING:
Fig. 1 is an axially extending cross-sectional view of an expanding sleeve embodying the pxesent invention;
Fig. 2 is an axial cross-sectional view taken along the line II-II of the sleeve shown in Fig. l;
Fig. 3 is a top view of the sleeve illustrated in Fig. l;
Fig~ 4 is a side view of an expanding element formed in accordance with the present invention;
Fig~ 5 is a side view of the ex~panding element shown in YigO 4 and turned 90;
30Fi~. 6 is~a top uiew of the expanding element illustrated ,:

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in Fig. 4:
Fig. 7 is an assembled view of the expanding sleeve of Fig. 1 and the expandinq element of Fig. 4 assembled together a~ an expansion anchor and inserted into a bore in a receiving material wi~h the ancho~ ~n the unexpanded po~ition;
~~~ - Fig. 8 i an axially extending sectional view of another expanding sleeve embodying the present invention and taken along the line VIII-VIII in Fig. 9;
Fig. 9 is a side view of the expanding sleeve shown in Fig. 8; and . ~ .
Fig. 10 is a combination of the expanding element of Eig. 4 and the s}eeve of Fig. 8 assembled together as an expansion anchor and positioned within a hole in a receiving material with the anchor in the unexpanded condition.
In Figs. 1, 2 and 3, an expanding sleeve 1 is illustrated.
The inner surface la of the sleeve has an elliptical shape for the greater axial length of the inner surface. As viewed in Figs. 1 and

2, the upper and of the sleeve is its leading or first end, that is the end which is first inserted into a borehole in receiving material. The opposite or lower end of the sleeve i~ its krailing or second end. The elliptically shaped surface la extends from the leading end toward the trailing end and merges into a circular surface adjacent the trailing end. By comparing Figs. 1 and 2, it can be appreciated that in Fig. 1 the opposite sides of the surface la diverge or widen toward the leading end, while in Fig. 2 the opposite sides of surface la are approximately parallel and in line with the circular surface of the passage through the sleeve at the trailing end. The leading end of the sleeve i~ designated lb, whilP ~he trailing end is designated lco Fur~her, t~a outer .: ~ '.'.
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surface ld of the sleeve is circular, note Fig~ 3 or itting into a circular borehole formed in a receiving material. At the trailing end lc of the sleeve, a stop 2 in t'he form of a flange, extends radially outwardly from the outer surface ld.
rwO slots 3 extend in the axial direction of the sleeve and also :
extend from the inner surface la to the outer surface ld. One of the s,lots 3 extends for the full length of the sleeve from its trailing end lc to its leading end lb, however, the other slot extends, from t~e leading end ld to a point short of -the trailing end lc whic~l corresponds -to the end of the stop 2 facing toward the leading end. The number of slots 3 can be varied and are adapted to the particular use' to which the sleeve is placed.
In Figs, 4, S a~nd 6, an expanding element 4 is displayed which is intended to he used in dependently supporting objects~ As can be seen in Fig. 6, the expanding element 4 has a part 4a which is elliptical in transverse cross section comparable to the transverse cross section of the inner surface la of th.~e sleeve 1, note Fig. 3. The outer surface 4b of the part 4a widens toward the upper end of the element which upper end is the leading or first end of the element comparable to the leading end lb of the sleeve. At the trailing end of part 4a t its elliptically shaped cxoss section merges into a cylindrical shape which is bounded by a collar S which extends radially outwardly from the cylindrical sectionO On the opposite side of the collax S from the part 4a, an eye-shaped part 6 is provided with a transverse bore 7 which is formed to receive other members.
In FigO 7 the sleeve 1 of Figs. 1 - 3 and the e-xpanding element 4 of Figs. 4 - 6 are assembled into an expansi~n anchor inserted into a borehole 11 fo~med in a receiving material llb.
The assembly of the sleeve 1 and the element 4 is especially ~ .
,, ~
' facilitated by the slot 3 which extends over the full axial length of the sleeve extending through the stop 2.
The assembled expansion anchor, as shown in Fig. 7, is inserted into the borehole 11 untii the stop 2 contacts the outer surface lla of the receiving ma-terial~ By turning or rotating the expanding element 4 about its axial direction in either direction for about 90~, the sleeve 1 will be expanded into locking engagement with the surface of the borehole 11.
Since the inner surface la of the sleeve widens on two opposite sides toward the leading end lb, and since the expanding element ::
4 has a similar shape on its outer surface, a force component is generated which has -the tendency to displace the expanding element 4 in its axial direction toward the bottom of the borehole 11. This component tends to pull the collar S into the hole, however, since the collar bears against the trailing end lc of the sleeve and the stop or flange 2 on the end of the sleeve -:
bears against the outer surface lla of the receiving material llb, there is an expanding action transmitted to the sleeve which causes it to be anchored in the bore ll. With the expansion anchor 2~ secured within the borehole, when a force or load is applied to the expansion element 4, that is, when an object is dependently ~
supported on the element 4~ an axial movement is produced in the 1;
element relative to the sleeve 1 which results in a further expansion of the sleeve due to the complementary tapering surface of the inner surface la of tha sleeve and the outer surface 4b of the expansion element.
In Figs. 8 and 9, another embodiment of an expansion ; sleeve 8 is shown for use with the expanding element 4 shown in Figs~ 4-6. The inner surface 8a of the sleeve 8 has an elliptical shape in transverse section, widening toward the leading end 8b .

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7~3 of the;sleeve. Further, the sleeve has slota 9 which are inclined to -the axial direction of the sleeve. ~xtending from the le~ading end 8b of the sleeve is a web me~ber 10 consisting of a pair of legs extending axially from diametrically opposed sides of the leading end with a web extending transverely across the outer ends of the legs. The web portion of the member 10 acts as an abutment when used in combination with t~le expanding element.
In Fig. 10, the sleeve 8 is assembled with the expanding e]ement 4 in Figs. 4 - 6 to provide an expansion anchor illust~ated in the unexpanded condition. As can be seen in Fig.
10, axially directed force components developed by rotating the expanding elemellt 4 within the sleeve 8 acts against the web oE
the web member 10. Accordingly, an abutment on the expanding element 4 is unnecessary. The collar 5 on the element 4 serves to limit the depth to which the entire assembly is displaced inwardly from the surface lla of the receiving material llb.
, Accordingly, a stop 2 on the expanding sleeve as shown in Figs~
1 - 3 can be eliminatçd.
When the expanding sleeve 8 widens, the web portion on the we4 member 10 i3 displaced oppositely to the direction of insertion of the anchor into -the borehole, dependending on the extent of the widening. This effect results in a desirable axial o~ longitudinal adaptation, particularly with large borehole tolerances or soft receiving material, so that in such cases optimum spreading is obtained by the complete utilization of the`angle of torque.
Having described what is believed to be the best mode by which the invention may be performed, it will be 30 seen that the invention may be particularly defined as follows,:
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An expansion anchor particularly for use i.n dependently supportlng an object, comprising an axially elongated sleeNe including an annular wall having an outer su:r~ace and an inner surface defining an axially extending passage within the sleeve, said sleeve having a first end and a second end with said ends ,:
spaced apart in -the axial direction of said sleeve, said sleeve wall having at least one slot extending ther~ethrough and in the axial direction of said sleeve, and an axially extending expansion element having an axially extending outer surface with an axially extending portion of said outer surface located within .the passage in said sleeve and forming the expanding surface.of said element, the expanding surface of said element having a first end ànd a se~ond end spaced apart in the.axial direction of said element, the first end of said sleeve spaced from the second end of said sleeve in the same direction along the axis as the first end of said expanding surface is spaced . .
from the second end of the ~xpanding surface, wherein the l improvement comprises that said expanding surface formed .. ` integrally with said expansion element, the cross-sectional shape of the passage in said sleeve and of the expanding ! surface of said expansion element extending transversely of .
the axial direction of said sleeve and expansion element, respectively) vary from a circular cross-section and at least : a part of the axially extending surface of the passage in said sleeve and of the expanding surface of said expansion element ~ having a dimension in the radial direction relative to the i axis o~ said sleeve and expansion element, respectively, which .l increases in the direction toward the first end of said sleeve ~
and expanding surface, respectively, said expansion element ~ .
: 30 being rotatable about its axially extending direction relative . ~.

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to the inner surface of said sleeve, said expansion element including abutment means for preventing axial displacement of said expansion element relative to said sleeve when it is rotated within said sleeve, and the se~ond end of said expansion element projecting axially out~ardly from the 'second end of said sleeve and including means for rotating said expansion element.
'l'he invention further comprises such an e~pansion .-anchor wllerein said at least a part of the axially exten-l.Lng outer surface of the expansion element having the increasing diameter in .:
the radial direction extends in the axial direction for the full extent of -the passage which has the transverse cross-sectional shape varying from a circular cross-section.
The invention further comprises such an expansion anchor wherein the expanding surface of said expansion element for its full axial extent continuously widens in at least one diametrical direction toward the first end of said expanding surface and the inner surface of said sleeve having an axially extending complementary shaped portion the.reto~
The invention further comprises such an expansion anchor wherein said abutment is an annular collar formed integrally on said expansion element and arranged to contact the second end of said sleeve and having an outside diameter greater than the maximum diameter of the pa~sage through said sleeve at its second end.
hile specific embodiments of the invention have been shown and described in detail to illustrate the applicatlon of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.
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Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An expansion anchor particularly for use in dependently supporting an object, comprising an axially elongated sleeve including an annular wall having an outer surface and an inner surface defining an axially extending passage within the sleeve, said sleeve having a first end and a second end with said ends spaced apart in the axial direction of said sleeve, said sleeve wall having at least one slot extending therethrough and in the axial direction of said sleeve, and an axially extending expansion element having an axially extending outer surface with an axially extending portion of said outer surface located within the passage in said sleeve and forming the expanding surface of said element, the expanding surface of said element having a first end and a second end spaced apart in the axial direction of said element, the first end of said sleeve spaced from the second end of said sleeve in the same direction along the axis as the first end of said expanding surface is spaced from the second end of the expanding surface, wherein the improvement comprises that said expanding surface formed integrally with said expansion element, the cross-sectional shape of the passage in said sleeve and of the expanding surface of said expansion element extending transversely of the axial direction of said sleeve and expansion element, respectively, vary from a circular cross-section and at least a part of the axially extending surface of the passage in said sleeve and of the expanding surface of said expansion element having a dimension in the radial direction relative to the axis of said sleeve and expansion element, respectively, which increases in the direction toward the first end of said sleeve and expanding surface, respectively, said expansion element being rotatable about its axially extending direction relative to the inner surface of said sleeve, said expansion element including abutment means for preventing axial displacement of said expansion element relative to said sleeve when it is rotated within said sleeve, and the second end of said expansion element projecting axially outwardly from the second end of said sleeve and including means for rotating said expansion element.

2. An expansion anchor, as set forth in Claim 1, wherein said at least a part of the axially extending outer surface of the expansion element having the increasing diameter in the radial direction extends in the axial direction for the full extent of the passage which has the transverse cross-sectional shape varying from a circular cross-section.

3. An expansion anchor, as set forth in Claim 1, wherein the expanding surface of said expansion element for its full axial extent continuously widens in at least one diametrical direction toward the first end of said expanding surface and the inner surface of said sleeve having an axially extending complementary shaped portion thereto.

4. An expansion anchor, as set forth in Claim 1, wherein said abutment is an annular collar formed integrally on said expansion element and arranged to contact the second end of said sleeve and having an outside diameter greater than the maximum diameter of the passage through said sleeve at its second end.

5. An expansion anchor, as set forth in Claim 1, wherein said abutment comprises a web member having a pair of legs each secured to a diametrically opposite side of the first end of said sleeve and extending outwardly from the first end in the axial direction of the sleeve and in the direction away from the second end thereof, and a web extending transversely of the axial direction of said sleeve and between the ends of said legs spaced outwardly from the first end of said sleeve.

6. An expansion anchor, as set forth in Claim 4, wherein an annular flange is formed integrally with said sleeve and extends radially outwardly from the outer surface of said sleeve and is located at the second end of said sleeve for limiting the extent to which the sleeve can be inserted into a hole having a diametrical size conforming to the outer surface of said sleeve.

7. An expansion anchor, as set forth in Claim 5, wherein said expansion element has an annular stop integral therewith and spaced in the axial direction of said element from the second end of the expanding surface on the opposite side thereof from the first end of the expanding surface and said stop extending transversely of the axial direction of said element and having an outside diameter greater than the outside diameter of said sleeve at the second end of said sleeve.

8. An expansion anchor, as set forth in Claim 1, wherein the outside diameter of said sleeve has a circular shape in the direction transverse to the axial direction of said sleeve.

9. An expansion anchor, as set forth in Claim 1, wherein the at least one slot in said sleeve is positioned at an angle to the axis of said sleeve.

10. An expansion anchor, as set forth in Claim 1, wherein said means for rotating said expansion element is formed in-tegrally therewith and extends axially outwardly from the second end of the expanding surface of said expansion element projecting outwardly beyond the second end of said sleeve, and said means includes an opening therein within which another member can be engaged for rotating said expansion member.