US3837257A

US3837257A - Anchoring device

Info

Publication number: US3837257A
Application number: US00280885A
Authority: US
Inventors: A Fischer
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-08-17
Filing date: 1972-08-15
Publication date: 1974-09-24
Anticipated expiration: 1991-09-24
Also published as: RO61294A; NO130549C; IL39893A; YU195372A; JPS4831358A; YU34602B; IT964030B; CH544235A; FR2150119A5; IL39893A0; BE786909A; DK133312B; AU4469372A; SE382096B; DD98556A5; IE36869L; CS161058B2; NL7211205A; AT315446B; DK133312C

Abstract

A helically convoluted spring sleeve of soft wire is insertable into a bore hole. An expander member has one part located forwardly of the leading end of the sleeve, and another part located in the leading end and tapering towards the trailing end of the sleeve. A cap sleeve has one section located outside and in abutment with the trailing end of the sleeve, and another part located within the trailing end. An expanding screw extends through a central passage of the expanding sleeve and through the spring sleeve into engagement with the expander member so that the latter can be drawn into the spring sleeve for radially expanding the same.

Description

United States Patent .1191

Fischer 1 Sept. 24, 1974 1 ANCHORING DEVICE 3,202,034 8/1965 Korenchan 85/75 Inventor: Artur Fischer, Altheimer Strasse 3,313,200 4/1967 Fischer 85/75 219 13-7241 Tumlingen, Germany FOREIGN PATENTS OR APPLICATIONS 79,321 11/1951 Norway 85/64 [22] 1972 128,326, /1956 Sweden [21] Appl, No; 280,885 249,955 /1966 Austria 1,022,013 3/1966 Great Britain 85/64 Foreign Application Priority Data Primary Examiner-Edward C. Allen Aug. 17, 1971 Germany 2141079 Attorney, Agent, or FirmMichael S. Striker Sept. 14, 1971 Germany 2145918 Dec. 15, 1971 Germany 2162255 [57] ABSTRACT Dec. 14, 1971 Germany 2164587 A convoluted p g sleeve of Soft wire is sertable into a bore hole. An expander member has [52] US. Cl 85/64, 85/67, 85/73 one part located forwardly of the leading end of the F161) Sleeve, and another p located in the leading end [58] d 0 Search 85/64 75 and tapering towards the trailing end of the sleeve. A 6 R f cap sleeve has one section located outside and in abut- [5 1 e erences C'ted ment with the trailing end of the sleeve, and another UNITED STATES PATENTS part located within the trailing end. An expanding 570,786 11/1896 Church /67 screw extends through a central passage of the ex- 768,283 8/1904 Jenkins 85/64 panding sleeve and through the spring sleeve into en- 1,120,409 12/1914 1101111161! et a1. 85/67 gagement the expander member so that the latter g; i acan be drawn into the spring sleeve for radially exenne y 1,395,453 11/1921 Peirce 85/74 pandmg the Same 1,852,297 4/1932 Gelpeke 85/67 15 Claims, 9 Drawing Figures Ito.

f 0':- J 9 jia .f Q 9 t O PATENTEDSEPM 1w ales-r257 SHEET 38$ 4 ANCHORING DEVICE BACKGROUND OF THE lNVENTlON The present invention relates to an anchoring device for fastening in a drill or bore hole formed in concrete construction components.

When testing a known device of this kind, it has been found that a fastening effect which resists large extraction forces could not be achieved. That device usesan expansible helical spring and it was found, surprisingly, that spring coils in the zone of the conical expansion body overlap during axial tensioning and are strongly pressed into the wall of the drill hole. Consequently, the fastening action was restricted to two, but in most cases to only one coil. Moreover, when an extraction force was applied in direction axially of the hole, the coil that was pushed against the wall of the drill hole slid over the expansion body, so that the expansion body was inserted into the spring past the tensioned coil. No tensioning of the spring coils could be achieved in the zone of the mouth of the drill hole which, as is known, is often both larger than the desired diameter and not circular.

SUMMARY OF THE INVENTION It is a general object of the invention to provide an anchoring device of the kind described above, that permits the application of large extraction forces in concrete construction elements without damage to the wall.

A further object of the invention is to provide such a device which can be manufactured very simply and economically.

Another object of the invention is to provide such de- A vice which achieves, with only a single spring sleeve, an effective fastening over that region of the spring upon which the expansion body or member of the device acts.

This is achieved, according to one feature of the invention, by winding the spring sleeve as a block spring, providing the expansion body at its insertion end with a collar, the outside diameter of which corresponds to the diameter of the drill hole, and arranging at the trailing end of the spring sleeve opposite the insertion or leading end thereof a cap having two sections, one section protruding into the spring sleeve and the other section covering the front face of the latter.

To fasten the device according to the invention, a bore or drill hole is first produced in a structure in which the device is to be anchored; the diameter of the bore corresponds to the outside diameter of the spring sleeve. The device is now inserted into the drill hole together with the expansion body and with the fixing or expanding screw, a few threads of which have been screwed into the expansion body. In hard concrete it is hardly possible to produce a perfectly cylindrical hole. Due to its elasticity the spring sleeve, however, adapts itself to the wall of the drill hole and thus achieves, before the expansion body has been inserted, a'bracing action which is sufficient to prevent the twisting of the device in the drill hole when the expansion body is inserted. At the same time, the coils of the spring sleeve at the leading end thereof also exert a bracing action upon the expansion body, so that the latter cannot twist in relation to the spring sleeve when the fixing screw is subsequently turned.

During insertion'of the device into the drill hole, some of the convolutions of the spring sleeve are pushed radially outwards against the wall of the drill hole by the cone of the expansion body. At the same time, the device is shortened due to axial contraction and radial expansion of the sleeve, so that the remaining coils of the spring sleeve overlap and are thus clamped into the space betweenfixing screw and the drill hole wall.

Only radial expansion forces are effective in the anchoring of the device according to the invention, and the expansion action and the pressure are uniformly distributed over a great length and circumference, independent of uneven and irregular zones of the wall of the drill hole. Through this so-called soft fixing, locally increased surface pressures which destroy the concrete structure, are avoided, and chipping is eliminated, so that break-out cones are not formed in the concrete.

It is a further advantageous effect of the spring sleeve of the novel device, that the expansion action increases with increasing extraction force. Tests have even proved that after applying a first high extraction force, which was followed by a short displacement and subsequent renewed engaging of the device in the drill hole, a higher second extraction force could be applied and would not lead to the extraction of the device. This factor, which is essential for the safety of the fastening action, thus meets a demand which is frequently made for statics considerations.

Due to the uniform pressure distribution of the device and due to the absence of a chipping action, a drill hole of small depth suffices for effective fastening, for example for supporting components of suspended ceilings, tubes, or other elements.

In the device according to the invention, the spring sleeve in effect as a dowel sleeve and as an expansion sleeve,'that is as adowel body. Without impairing the function of the dowel, it is thus possible to shorten the length of the dowel by cutting the spring wire. It is thus possible for the first time to adapt, by cutting its expansion sleeve, a metal dowel to any drill hole depth and to any purpose.

The cap serves for guiding the spring and, moreover, prevents jamming and tilting of the first coil or convolution at the trailing end of the spring sleeve in the bore of an object to be secured.

According to one embodiment of the invention, the spring sleeve may be wound from soft wire, in particular from copper wire. This facilitates the insertion of the expansion body into the spring sleeve, because a sleeve of soft wire can be more easily expanded by the expansion body.

Advantageously, the spring sleeve may be wound right-handed. Due to its elasticity, the spring sleeve pushes against the cone of the expansion body in such a manner that under normal conditions the expansion body cannot twist in relation to the spring sleeve. If, however, twisting should happen nevertheless, for example if the thread of the fixing screw is damaged, the spring sleeve whose coils are in contact with the expansion body, is also twisted in clockwise direction as the screw is rotated. In the case of right-handed winding of the spring sleeve, however, the latter will then contract and engage the expansion with increasing pressure until the action which prevents twisting is again fully effective.

Further, the end of the wire at the insertion or leading end of the spring sleeve may be bent outwards. When the fixing screw is screwed in, this wire end engages with the wall of the drill hole and thus also contributes to the prevention of spring twist in relation to the drill hole.

According to another advantageous embodiment of the invention, the expansion body may contain at its trailing end opposite its leading or insertion end a cylindrical attachment or portion, the outside diameter of which corresponds to the inside diameter of the spring sleeve. This attachment serves for centering the expansion body in the spring sleeve.

According to a further concept of the invention, a collar that engages in the coils of the spring sleeve may be arranged at the attachment. This collar is advantageously formed with a thread. The expansion body can thus be screwed into the spring sleeve without the possibility of being lost, so that it is easily possible to unthread the fixing screw from the expansion body after the device according to the invention has been anchored in the bore hole.

Finally, at least part of the outer surface of the attachment may be roughened, as for example by knurling. This construction increases the friction between the spring sleeve and the expansion body still further, so that twisting of the expansion body in relation to the spring sleeve is excluded.

Without departing from the concept underlying the present invention, it is also possible to configurate the thread section of the fixing screw in such a manner that the outside diameter of the spring sleeve corresponds to the shaft diameter of the fixing screw.

This construction permits so-called push-through assembly, which saves time and expense because the bore holes in the basic support structure and in the element to be fastened to it, are formed simultaneously with the element being in position on the support structure. Then the device is simply pushed from the exposed side of the element through the bore hole thereof so as to extend partly into the bore hole of the support structure, andis thereupon anchored. In order to increase the expansion effect, the end of the shaft of the fixing screw may in addition be conically tapered in the direction of the thread section, so that the spring is braced between the cones of the expansion body and the fixing screw opposite one another.

In the same manner, the section of the cap that protrudes into the longitudinal passage of the spring sleeve may be tapered in the direction of the leading or insertion end.

The novel device thus comprises a spring sleeve and two opposed cones as expansion bodies. bracing the spring sleeve in the drill hole. The spring sleeve itself forms or acts as a dowel body that can be widened, i.e. radially expanded. By screwing in the fixing screw, the expansion body is drawn towards the trailing end of the sleeve, i.e. in the direction of the cap provided with a cone, which is supported by the object to be fixed. The reduction of the gap between the two opposite cones effects an axial shortening of the spring, the coils of which thus undergo concomitant radial expansion and are pushed against the wall of the drill hole. Moreover, the two cones penetrate into the passage of the spring sleeve and further expand the latter. Two factors are thus essential for the fastening of the device, which by their cooperation contribute to the achievement, by

means of the device according to the invention, of retention values which far surpass those of known anchoring devices.

According to another advantageous embodiment of the invention, a cylindrical attachment may be provided on the cone of the cap, the outside diameter of which attachment corresponds to the inside diameter of the spring sleeve. This latter attachment serves for centering and guiding the spring sleeve.

A further embodiment provides for a collar which engages in the coils of the spring sleeve and which may be arranged at the attachment. By means of this collar, the

cap is connected with the spring sleeve without the possibility of being lost.

As a rule, the device is mounted flush with the wall. Since the outside diameter of the fixing screw to be screwed into the expansion body is smaller than the outside diameter of the device per se, this means that the fixing screw is free in the object to be fixed. How ever, the object to be fixed has thus no support, and the device also lacks a counter bearing when the expansion body is drawn in by means of the fixing screw, due to the equality. of the drill hole diameters in the wall and in the object to be fixed, which counter bearing should of course prevent the withdrawal of the device from the drill hole.

This is avoided according to another advantageous embodiment of the invention by constructing the cap as a tubular element which extends rearwardly beyond the trailing end of the spring sleeve.

Before the device according to the invention is fastened, a hole is drilled into the wall through the object to be fixed, the diameter of which hole corresponds to the outside diameter of the device. Without having to remove the object to be fixed from the wall, the device may then be inserted to such an extent that its upper end is flush with the outer surface of the object to be fixed (push-through installation). By drawing in the expansion bodyby means of a stay bolt and a nut, or, respectively, a cap screw, the device is then anchored fastened in the drill hole and the object is secured to the wall.

In an advantageous embodiment, the rearwardly extended portion of the cap may be provided with a circumferential recess of saw-toothshaped cross section, and which has a distance from the trailing end of the device that preferably corresponds to the thickness of an object to be fixed. The reduction in the wall thickness of the cap which is caused by provision of this recess has the result that an upset occurs when the fixing screw is screwed in further, or the nut is tightened further, after the anchoring of the device in the zone of the change of the cross-section, which upset enables the object to be fixed to be braced particularly rigidly to the wall.

The recess has the further advantage. that the rear section which is separated by this recess from the remainder of the cap can be readily removed when not needed. This is desirable when, for example, the thickness of the object to be fixed is small and the rear section therefore not needed. In mass production it is expedient to restrict the spacing of the recess from the trailing end of the device to a few selected distances. As

a rule, it will nevertheless be possible to readily find the selected distances may be compensated by inserting the device more deeply into the bore hole.

The necessity of tightly drawing the anchored object against the surface of the concrete support structure or the like, once the device has been anchored in the bore hole of the latter, by corresponding tightening of the nut or screw, pre-supposes a further penetration of the rearwardly extended cap into the drill hole, because in the case of a push-through assembly, as is known, the cap is in contact with the nut or the head of the fixing screw. This can be achieved by so constructing the spring sleeve that over the major part of its length adjacent coils or convolutions forming the spring sleeve are in the nonexpanded state of the sleeve in immediate contact with one another in the manner of a block spring, while the remaining (trailing) part of the sleeve, which faces away from the expansion body, has its coils located at a distance from one another.

In this embodiment, the part of the spring sleeve which is wound in the manner of a block spring is first expanded by drawing in the cone by means of the fixing screw and is thus braced against the wall of the drill hole.

The block spring-type part of the spring sleeve is already stationarily fastened in thedrill hole by this bracing. When the expansion body is drawn in still further, the fastening effect is further reinforced on the one hand, while on the other hand the cap is now drawn forwardly into the drill hole to such an extent that those coils which were previously not in contact with one another will now move into such abutment.

When this state has been reached, the anchoring of the device in the drill hole, as well as the bracing of the object which is to be fixed between the head of a screw or the nut of a screw bolt and the surface of the structure in which the device is anchored are completed. The desired bracing of the object to be fixed can also be achieved by providing the center passage of the extended cap with a short widened bar section extending inwardly from its free rear end face.

This widened bore section results in the cap having in the zone of its free rear end face a region of reduced wall thickness, which can give way after the anchoring of the device in the drill hole and when the fixing screw or the fixing nut are thereupon further tightened, so that in this embodiment too, a bracing of the object to be fixed to the surface of the support structure is made possible. The region of reduced wall thickness carries the further advantage that when a stay bolt with fixing nuts is used, and the drill hole has inadvertently been drilled oblique, complete contact of the fixing nut and the surface of the object to be fixed can nevertheless be achieved. The region of reduced wall thickness will partially yield so that the nut can take up a position perpendicular to the axis of the bore, the stay bolt being given a slight deflection in that its end protruding from the bore hole is bent in the direction of the axis of the bore.

The retention values of the novel device can be increased still further if a better pressure distribution in the zone of the expansion body can be achieved and, moreover, if sliding of the coils over expansion body is prevented when the latter is drawn in.

This is achieved by arranging between the cone and the collar of the expansion body a cylindrical section with a diameter corresponding to the largest diameter of the cone, the length of which cylindrical section suffices for taking up at least one coil of the spring.

By means of the cylindrical section, the outside diameter of which corresponds to the largest diameter of the cone, several coils are expanded to the same outside diameter, so that several coils are pressed with maximum pressure against the wall of the drill hole. This results in further improvement of the pressure distribution, which increases the retention values. The collar at the leading or insertion end of the expansion body, whose diameter corresponds to the inside diameter of the drill hole, prevents a further sliding back of the spring sleeve, so that the other coils too contribute to the fastening of the device by the shortening of the spring sleeve. Two factors are thus essential for the fastening, the cooperation of which makes the achievement of high extraction values possible.

The increase in the retention values of the device depends substantially upon the length of the cylindrical section. An increase may already be achieved if the section has a length which suffices for taking up one coil. Tests have shown, however, that an optimum value of the increase is achieved when the cylindrical section is given sufficient length to permit two to four coils to be taken up.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a device according to the invention, inserted into a concrete support structure;

FIG. 2 illustrates a special construction of an expansion body;

FIG. 3 shows a device according to the invention in a different embodiment, inserted into a concrete. sup-.

port structure;

FIG. 4 illustrates an embodiment permitting pushthrough assembly;

FIG. 5 shows a special construction of a cap;

FIG. 6 shows an embodiment of the device having a rearwardly extended cap;

FIG. 7 illustrates a special construction of the free rear end of a cap;

FIG. 8 shows a special construction of a spring sleeve; and I FIG. 9 shows a special construction of an expansion body.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The device according-to the invention as shown in FIG. 1 comprises a spring sleeve I wound from wire in the manner of a block spring. A fixing screw 3 meshes with an expansion body 2. By screwing the fixing screw 3 into the conical expansion body 2, the latter is drawn axially into the spring sleeve 1. The coils or convolutions at the leading end portion of the spring sleeve 1 are thus widened and pushed radially outwardly against the wall of the drill hole 7 formed in a concrete support structure 8.

The expansion body 2 further has at its leading or insertion end a collar 4, the outside diameter of which corresponds to the inner diameter of the drill hole. A cap 5 is set upon the rear or trailing end of the spring sleeve 1, having one section which protrudes into the center passage of the spring sleeve 1, and another section which covers the rear end face of the spring sleeve 1. This prevents the first coil at the trailing end of the spring sleeve 1 from jamming or tilting in the drill hole of an object 6 to be fixed to structure 8. The coils of the spring sleeve 1 adapt themselves to the irregular form of the drill hole 7 in the concrete support structure 8 and thus prevent by their intrinsic tension force a twisting of the spring sleeve 1 when the device is fastened.

The expansion body 2 shown in FIG. 2 has at its trailing end opposite the leading or insertion end an additional cylindrical portion or attachment 9, the outside diameter of which corresponds to the inside diameter of the spring sleeve 1. A collar 10 is arranged at the front end of the attachment, which collar engages between the coils of the spring sleeve. This collar 10 is advantageously formed as or with a thread.

In the embodiment shown in FIG. 3, the cap 5 has two sections 5a, 5b, of which the section 5a protrudes into the bore of the spring sleeve 1 and the section 5b covers the rear end face of the spring sleeve 1. The section 5a is conically tapered in direction towards the expansion body 2. When the expansion body 2 is drawn in, the spring sleeve 1 is thus braced between the two opposite cones of the expansion body 2 and the cap 5 by means of the fixing screw 3. The cap 5 is supported by the object to be fixed and thus aids in preventing a withdrawal of the spring sleeve 1. I

FIG. 4 shows an embodiment in which a section 3a of the fixing screw which engages in the expansion body 2, in the spring sleeve 1 and in the cap 5, is set off. The outside diameter of the shaft 3b of the fixing screw 3 corresponds to the outside diameter of the spring sleeve 1. When the expansion body 2 is drawn in, the cap 5 is in this embodiment supported by the front face 11 of the shaft 3b of the fixing screw 3. In this embodiment it is also possible to make the cap and the fixing screw of one piece.

The cap 5 shown in FIG. 5 is provided, as an extension of its cone with an additional cylindrical portion or attachment 12 the outside diameter of which corresponds to the inside diameter of the spring sleeve 1. A collar 13 is arranged at the front end of the attachment and engages between the coils of the spring sleeve 1. This collar is advantageously formed as or with a thread.

According to FIG. 6 the section 5b of the cap 5 is rearwardly extended and serves for the support of the object 6 which is to be fixed to the support structure. The fact that the outside diameter is uniform over the entire length of the device makes push-through assembly possible, in which the same drill hole diameter is required both in the object 6 to be fixed and in the support structure 8.

The circumferential saw tooth-shaped recess subdivides the extended section 5b of the cap 5 into two parts, the length of the upper part 5c corresponding approximately to the thickness of the object 6 to be fixed. The saw tooth-shaped recess 20 serves on the one hand as knock-off notch for the upper part 5c and on the other hand as an upsetting zone which should render it possible for the fixing screw 3 to be drawn, after the anchoring of the device is completed, in the direction toward the surface of the structure 8 for bracing the ob ject 8 between such surface and the head of screw 3.

FIG. 7 shows another construction of the recess 20, which is easier to manufacture. In this case, the free rear end of the cap 5 is provided with a wider bore section 23 which ensures a lower wall thickness of the cap in the zone of the rear end thereof. In the zone of the thus reduced wall thickness, the cap may give way in axial direction when an axial force is applied, by crumpling. The section 23 may be connected with the remainder of the bore by a tapered bore section 23'.

FIG. 8 shows a special embodiment of the spring sleeve. In the non-expanded state, the coils of the major part 22 of the spring sleeve are in immediate abutting contact with one another in the manner of a block spring, while the coils of the remaining part 21 which faces away from the expansion body 2, are spaced from one another. The cap 5 can be moved in the direction of the expansion body 2 by the total amount of the distances between the coils of the smaller part 21, by deflecting the coils thereof into abutment with one another.

In FIG. 9, the expansion body 2 has a cone 30 and at its insertion end a collar 4, the outside diameter of which corresponds to the inner diameter of the drill hole 7. A cylindrical section 31 for taking up at least one coil of the spring sleeve 1 is arranged between the cone 30 and the collar 4. The diameter of this section 31 corresponds to the largest diameter of the cone 30. A head screw or a stay bolt with nut may selectively be used as the fixing screw 3,

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in an anchoring device, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. An anchoring device for use in bore holes formed in structures, particularly bore holes formed in concrete structures, comprising a helical block-spring expansion sleeve having a leading and a trailing open axial end; discrete internally threaded expander member located at said leading axial end and including a substantially cylindrical first portion located exteriorly of said leading axial end and having a shoulder with an outer diameter greater than the inner diameter of said spring sleeve, a second portion located in said leading axial end and converging in direction toward said trailing axial end, and a cylindrical intermediate third portion located between said first and second portions and having an axial diameter equalling the maximum outer diameter of said second portion, and an axial length corresponding to the axial length of at least one convolution of said spring sleeve; threaded expanding means extending from said trailing axial end through said spring sleeve into threaded engagement with said expander member and being operable for advancing the latter in direction toward said trailing axial end to thereby effect radial expansion of said spring sleeve; and a discrete cap member at said trailing axial end and provided with an axial passage through which said expanding means extends, said cap member including a first section located within said trailing axial end'and a second section axially abutting said trailing axial end.

5. A device as defined in claim 1, said second portion of said expander member having an end region remote from said first portion and being of cylindrical configuration, said end region having an outer diameter corresponding to the inner diameter of said spring sleeve.

6. A device as defined in claim 5; and further comprising an outwardly projecting collar provided on said end region and adapted for engagement between respective adjacent convolutions of said spring sleeve.

7. A device as defined in claim 1, said expanding means comprising an elongated threaded bolt having a leading portion of smaller diameter received in said spring sleeve, and a trailing portion located outside said trailing end of said spring sleeve and being of a diameter corresponding to the diameter of said spring sleeve in non-expanded condition.

8. A device as defined in claim 1, wherein said first section of said cap member converges in direction to wards said leading end of said spring sleeve.

9. A device as defined in claim 1, wherein said first section of said cap member includes a leading end portion of cylindrical configuration and having an outer diameter corresponding to the inner diameter of said spring sleeve, and an intermediate portion connecting said leading end portion with said second section and converging in direction from the latter towards the former.

10. A device as defined in claim 9, said leading end portion including an outwardly extending collar portion arranged to engage between adjacent convolutions of said spring sleeve.

11. A device as defined in claim 1, said spring sleeve having a longer first sleeve section extending from said leading toward said trailing end, and a shorter second sleeve section extending from said first sleeve section to said trailing end; and wherein adjacent convolutions in said first sleeve section are in abutment in nonexpanded state of said spring sleeve, and adjacent convolutions in said second sleeve section are spaced from one another.

12. A device as defined in claim 1, said second section having a trailing endface remote from said first section; and wherein said axial passage has a widened passage portion extending from saidtrailing endface towards said first section.

13. An anchoring device for use in bore holes formed in structures, particularly bore holes formed in concrete structures, comprising a helical block-spring sleeve having a leading and a trailing open axial end; an expander member located at said leading axial end and including an annular first portion located exteriorly of said leading axial end and having an outer diameter at least equal to that of said spring sleeve, a second portion located in said leading axial end and converging in direction towards said trailing axial end, and a cylindrical intermediate third portion located between said first and second portions and having an outer diameter equalling the maximum outer diameter of said second portion and an axial length corresponding to the axial length of at least one convolution of said spring sleeve; expanding means extending from said trailing axial end into engagement with said expander member and being operable for advancing the latter in direction towards said trailing axial end to thereby effect radial expansion of said spring sleeve; a cap member at said trailing axial end and provided with an axial passage, said cap member including a first section located within said trailing axial end and a second section axially abutting said trailing axial end, said second section having an outer circumferential surface and a trailing endface remote from said first section; and a circumferential groove formed in said outer circumferential surface intermediate said trailing endface and said first section.

14. A device as defined in claim 13, wherein said groove is of substantially sawtooth-shaped crosssection.

15. A device as defined in claim 13, wherein said groove is spaced from said trailing endface by a distance which is selected to correspond to the thickness of a component which is to be connected to a structure,

via said device.

Claims

1. An anchoring device for use in bore holes formed in structures, particularly bore holes formed in concrete structures, comprising a helical block-spring expansion sleeve having a leading and a trailing open axial end; discrete internally threaded expander mEmber located at said leading axial end and including a substantially cylindrical first portion located exteriorly of said leading axial end and having a shoulder with an outer diameter greater than the inner diameter of said spring sleeve, a second portion located in said leading axial end and converging in direction toward said trailing axial end, and a cylindrical intermediate third portion located between said first and second portions and having an axial diameter equalling the maximum outer diameter of said second portion, and an axial length corresponding to the axial length of at least one convolution of said spring sleeve; threaded expanding means extending from said trailing axial end through said spring sleeve into threaded engagement with said expander member and being operable for advancing the latter in direction toward said trailing axial end to thereby effect radial expansion of said spring sleeve; and a discrete cap member at said trailing axial end and provided with an axial passage through which said expanding means extends, said cap member including a first section located within said trailing axial end and a second section axially abutting said trailing axial end.

2. A device as defined in claim 1, wherein said expanding means is an elongated threaded member.

3. A device as defined in claim 1, wherein said spring sleeve is of soft metallic wire.

4. A device as defined in claim 1, wherein said spring sleeve is of copper wire.

8. A device as defined in claim 1, wherein said first section of said cap member converges in direction towards said leading end of said spring sleeve.

11. A device as defined in claim 1, said spring sleeve having a longer first sleeve section extending from said leading toward said trailing end, and a shorter second sleeve section extending from said first sleeve section to said trailing end; and wherein adjacent convolutions in said first sleeve section are in abutment in non-expanded state of said spring sleeve, and adjacent convolutions in said second sleeve section are spaced from one another.

12. A device as defined in claim 1, said second section having a trailing endface remote from said first section; and wherein said axial passage has a widened passage portion extending from said trailing surface towards said first section.

14. A device as defined in claim 13, wherein said groove is of substantially sawtooth-shaped cross-section.

15. A device as defined in claim 13, wherein said groove is spaced from said trailing endface by a distance which is selected to correspond to the thickness of a component which is to be connected to a structure, via said device.