CA1168484A - Foundation bolt - Google Patents
Foundation boltInfo
- Publication number
- CA1168484A CA1168484A CA000342487A CA342487A CA1168484A CA 1168484 A CA1168484 A CA 1168484A CA 000342487 A CA000342487 A CA 000342487A CA 342487 A CA342487 A CA 342487A CA 1168484 A CA1168484 A CA 1168484A
- Authority
- CA
- Canada
- Prior art keywords
- sleeve
- section
- bore
- anchor bolt
- grooves
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- Dowels (AREA)
Abstract
Abstract An anchor bolt for anchorage in a bore has a tension rod with a male screwthreaded section and a head section conically enlarged from the latter. There is also a sleeve with a female screwthreaded section and an adjoining sectorally spreadable anchorage section. The invention is characterised in that the sleeve has a polygonal cross-section and is provided with axially parallel pre-weakened spreading lines in the middles of the sides of the polygon. The resulting bolt permits an immediate, secure and durable anchorage in surrounding material.
Description
:
- 2 -The invention relates to a foundation or anchor bolt for anchorage in a bore, comprising a tension rod having a screwthreaded cross-section and a head section conically enlarged from the latter, and a sleeve having a female screwthreaded section and an adjacent sectorally spreadable anchorage section.
Bolts of this type are known. They have a sleeve, the anchorage section of which is constituted by a hollow cylinder of circular cross-section provided with ax;ally 10 parallel slits. The screwthreaded section of the tension rod is screwed into a female screwthread in the sleeve from the direction of the anchorage section, and the assembly is introduced as a unit into a bore. The tension rod is then further rota-ted until it urges the spreadable 15 anchorage cross-section of the sleeve apart by its conical head section, thus anchoring the sleeve in the surrounding - material, such as timber, chipboards or concrete.
A disadvantage of the conventional such bolt lies in the fact that there is a danger that, when the tension rod 20 is tightened, the sleeve may follow its rotation in the bore, so that it cannot be spread and does not become anchored.
It is the object of the present invention to construct a bolt of the type mentioned in such a way that it 25 achieves immediate, secure and durable anchorage in the material.
;'~ i '' '.
'' : .
:.
This aim is achieved by means of an anchor bolt for anchorage in a bore, comprising (a) a tension rod having a : male screwthreaded portion terminating in a frusto-conical head portion diverging therefrom; and (b) a sleeve of polygonal cross-section having a female screwthreaded portion for engagement with said male screwthreaded portion of said tension rod, said female screwthreaded portion terminating in a frusto-conical bore diverging therefrom for engagement with said head portion of said tension rod;
(c) axially parallel grooves being provided in the middles of the polygonal sides of said sleeve, the conicity of said ~rusto-conical bore and the depth of said grooves being so selected that they converge to a substantial degree at the end of said bore remote from said female screw-threaded portion, to provide a sectorally spreadable anchorage section.
The polygonal, preferably hexagonal, cross-section of the sleeve reliably prevents the sleeve from following the rotation when the tension rod is tensioned. Furthermore, ; 20 the polygonal cross-sectional shape produces a number of additional sharp corners on the spreadable side of the sleeve which facilitate entry into the material ana locking in the material.
; The anchorage section of the sleeve has an internal conical shape that co-operates with the conical head section of the tension rod. The two conical surfaces together permit a gradual uniform spreading of the sleeve by a small force, so that also in this way the danger of the sleeve following the rotation of the tension rod or : 30 being withdrawn before anchorage is achieved, is reduced.
Grooves, which may have a vee-shaped cross-section, are preferably used as the pre-weakened spreading lines.
It is convenient to co-ordinate the depth oE the grooves and the course of the conical enlargement in the interior of the anchorage section of the sleeve so that the two converge substantia]ly at the free edge of the sleeve, so that an immediate tearing open and spreading of the sleeve is possible there.
The tension rod, which is known as such, may be of such construction that the conically enlarged head section constitutes a smooth cylindrical shank, at the end oE
which an enlargement in the form of a slot-screw or female hexagonal screw head is provided.
The sleeve may consist of various plastics or metals and may also more particularly be produced as an aluminium injection die-casting.
Further particulars of the invention will emerge from the subordinate claims.
Preferred exemplary embodiments of the invention are explained more fully hereinbelow with reference to the accompanying drawing, wherein:
Fig. 1 shows a partial section of an arrangement of tension rod and sleeve before assembly;
Fig. 2 is a larger scale elevation of the sleeve along the line 2-2 in Fig. l;
, ~
:~' `, ;' _ 5 - ~ig. 3 is a partial section o~ the foundation bolt during tensioning; and Fig, ~ iB an elev~tion along the line 4-4 ln ~ig. 3.
In ~ig. 1, a sleeve is designated 10 and a tension xod 12. ~he sleeve is constituted, in the longitudinal direction, by two sectionsg which are designated as a female screwthreaded section 14 on the le~t hand side in Fig. 1 and as a spreadable anchorage section 16 on lo the right-hand sidq in ~ig. 1. ~he female scre~threaded section 1l~ exhibits a concentric axial bore 18 with female screwthread. The anchora~e section 16 is provided internally with a bore 20 which widens . . ~
conically towards the free end to the right in Fi~. 1, ~he cone angle of this bore 20 is comparatively small and may be e.g., 3 to 4 referred to the longitudinal median line of the sleeve. As ~ig. 2 clearly shows, the circumference of the sleeve 10 is of hexagonal cross-section. Groove~ 22, which ma~ have e.g.~ a vee-3haped cross-~ection, are provided in ~he longitudinal median lines of the six planes, surfaces bounding thq 1eeve outwards.
~ he enlargement of the bore 20 and the depth of the groovas 22 are mutually co-ordinated in such a way that they converge ~ubstantially at the right-hand end of the sleeve in ~ig, 1, or at least are separated by a very slight thickness of material which can immediatel~
be interrupted.
.~ , _ 6 _ ~ he tension rod shown on the right-hand si~ ln ~ig. ~ comprises a screwthreaded section 24 provided with a male screwthr0ad and a frustoconical head section 26 ad~oining the same. ~he male screwthread -of the screwthreaded section 2~ corresponds to the femalo screwthread of the bore ~8. ~he frustoconical head section 26 need not ~ecessarily e~hibit a precise conical surface, but may also be bevelled or rounded in a different manner ~he head section 26 in the 1~ example illustrated mer~es into a c~lindrical shank 28 o~ any desired le~gth and a head 30 adjoining the latter for the application of a screwdriver or female hexagon key. However, other elements which permit a rotation and a bracing of the tension rod 12 to the left in ~ig. 1 may be provided instead of the shank and of the head 30.
During the assembly of the foundation bolt ~ccording to the invention, the scre~threaded section 2~ iB first of all passed through the anchorage ~ section 16 and screwed into the bore 18, until e~
the conical head section 12 is loos~ely in contact against the right~hand end of the slee~e. In this position the sleeve and the ten~ion rod are introduced as a unit into a bore~ which may be e.g., a bore in a concrete wall or in components made of timber or chip-boards. Box~shaped furniture items may be assembled e.g., by making blind hole~ in a board from each o~
its edges, and drilling holes with a countersink for the head 30 in associated positions of rectangularly ~ 7 --adjacent board~. ~hese possibilities o~ assembly are known per se and will therefore not be explained i~
de-tail.
~ he unit comprising sleeve 10 and tension rod 12 is introduced into the hole until the head 30 abuts against a suitable stop, e.g., the bottom of a sunk hole. ~en the tension rod 12 is further rotated in this position the sleeve 10 is attra¢ted due to the screwthread engagement between the scre~threaded sectlon 2~ and the bore 18 and simultaneously spread, as shown in ~ig. 3. During this spreading the anchor-age section 16 tears open in the region of the grooves 22 (~ig. 2) into individuRl segme~nts 32 (Fig. 2).
'~hese se~ent~ penetrate increasingly into the material of the ad~acent wall of the bore, so that the sleeve becomes anchored in the bore. The position o~ ~ig. 4 is then substantially obtained.
~ he cross-sectional shape of the sleeve 10 according to the invention not only has the advantage that a corotation of the sieeve during the tensioning operation i9 e~cluded. On the contrary, Fig. 4 clearly shows that the individual segments 32 con-stitute a lar~er number of sharp corners than is the case sayl of cylindrical spreadable sleeves. Said sharp corners ~acilitate the penetration into the material of the bore wall and hence the anchorage of the sleeve.
~ he foundation bolt according to the in~ention makes possible, for example, Q corner joint of box-shaped furniture items without fitting parts being visible on the external surface of the individual boards, with the exception of the head 30 let into a sunk bore, which can however if desired be used as a decorative element.
After the anchorage the sleeve 10 attains a fixed seat in the associated bore, which is still retained if the tension rod 12 is unscrewed in order to release the joint and possibly screwed back in again afterwards.
The feature of the grooves 22 being only pre-weakened but not fully broken, is of importance in connection with the feature of a frusto-conical bore in the sleeve. As a consequence of the combination of these two features, the strength of the pre-weakened spreading grooves increases from the rear end to the leading end of the sleeve. Thus, when the frusto-conical head portion of the tension rod is inserted into the sleeve, the spreading lines will grad-ually tear open from their respective rear ends. While, according to the prior art, as exemplified by British patents 725,291 of March 2, 1955 to Ericsson and 335,508 of September 25, 1930 to Wagner, the spreadable sectors of the anchorage section are pivoted about their respective - roots, according to the present invention, because of the gradual tearing open of the spreading lines (grooves), these sections are bent outwardly in an arcuate manner, and r hence, spread to a larger degree, so that anchorage is improved, particularly in soft material such as gas-concrete.
V
Bolts of this type are known. They have a sleeve, the anchorage section of which is constituted by a hollow cylinder of circular cross-section provided with ax;ally 10 parallel slits. The screwthreaded section of the tension rod is screwed into a female screwthread in the sleeve from the direction of the anchorage section, and the assembly is introduced as a unit into a bore. The tension rod is then further rota-ted until it urges the spreadable 15 anchorage cross-section of the sleeve apart by its conical head section, thus anchoring the sleeve in the surrounding - material, such as timber, chipboards or concrete.
A disadvantage of the conventional such bolt lies in the fact that there is a danger that, when the tension rod 20 is tightened, the sleeve may follow its rotation in the bore, so that it cannot be spread and does not become anchored.
It is the object of the present invention to construct a bolt of the type mentioned in such a way that it 25 achieves immediate, secure and durable anchorage in the material.
;'~ i '' '.
'' : .
:.
This aim is achieved by means of an anchor bolt for anchorage in a bore, comprising (a) a tension rod having a : male screwthreaded portion terminating in a frusto-conical head portion diverging therefrom; and (b) a sleeve of polygonal cross-section having a female screwthreaded portion for engagement with said male screwthreaded portion of said tension rod, said female screwthreaded portion terminating in a frusto-conical bore diverging therefrom for engagement with said head portion of said tension rod;
(c) axially parallel grooves being provided in the middles of the polygonal sides of said sleeve, the conicity of said ~rusto-conical bore and the depth of said grooves being so selected that they converge to a substantial degree at the end of said bore remote from said female screw-threaded portion, to provide a sectorally spreadable anchorage section.
The polygonal, preferably hexagonal, cross-section of the sleeve reliably prevents the sleeve from following the rotation when the tension rod is tensioned. Furthermore, ; 20 the polygonal cross-sectional shape produces a number of additional sharp corners on the spreadable side of the sleeve which facilitate entry into the material ana locking in the material.
; The anchorage section of the sleeve has an internal conical shape that co-operates with the conical head section of the tension rod. The two conical surfaces together permit a gradual uniform spreading of the sleeve by a small force, so that also in this way the danger of the sleeve following the rotation of the tension rod or : 30 being withdrawn before anchorage is achieved, is reduced.
Grooves, which may have a vee-shaped cross-section, are preferably used as the pre-weakened spreading lines.
It is convenient to co-ordinate the depth oE the grooves and the course of the conical enlargement in the interior of the anchorage section of the sleeve so that the two converge substantia]ly at the free edge of the sleeve, so that an immediate tearing open and spreading of the sleeve is possible there.
The tension rod, which is known as such, may be of such construction that the conically enlarged head section constitutes a smooth cylindrical shank, at the end oE
which an enlargement in the form of a slot-screw or female hexagonal screw head is provided.
The sleeve may consist of various plastics or metals and may also more particularly be produced as an aluminium injection die-casting.
Further particulars of the invention will emerge from the subordinate claims.
Preferred exemplary embodiments of the invention are explained more fully hereinbelow with reference to the accompanying drawing, wherein:
Fig. 1 shows a partial section of an arrangement of tension rod and sleeve before assembly;
Fig. 2 is a larger scale elevation of the sleeve along the line 2-2 in Fig. l;
, ~
:~' `, ;' _ 5 - ~ig. 3 is a partial section o~ the foundation bolt during tensioning; and Fig, ~ iB an elev~tion along the line 4-4 ln ~ig. 3.
In ~ig. 1, a sleeve is designated 10 and a tension xod 12. ~he sleeve is constituted, in the longitudinal direction, by two sectionsg which are designated as a female screwthreaded section 14 on the le~t hand side in Fig. 1 and as a spreadable anchorage section 16 on lo the right-hand sidq in ~ig. 1. ~he female scre~threaded section 1l~ exhibits a concentric axial bore 18 with female screwthread. The anchora~e section 16 is provided internally with a bore 20 which widens . . ~
conically towards the free end to the right in Fi~. 1, ~he cone angle of this bore 20 is comparatively small and may be e.g., 3 to 4 referred to the longitudinal median line of the sleeve. As ~ig. 2 clearly shows, the circumference of the sleeve 10 is of hexagonal cross-section. Groove~ 22, which ma~ have e.g.~ a vee-3haped cross-~ection, are provided in ~he longitudinal median lines of the six planes, surfaces bounding thq 1eeve outwards.
~ he enlargement of the bore 20 and the depth of the groovas 22 are mutually co-ordinated in such a way that they converge ~ubstantially at the right-hand end of the sleeve in ~ig, 1, or at least are separated by a very slight thickness of material which can immediatel~
be interrupted.
.~ , _ 6 _ ~ he tension rod shown on the right-hand si~ ln ~ig. ~ comprises a screwthreaded section 24 provided with a male screwthr0ad and a frustoconical head section 26 ad~oining the same. ~he male screwthread -of the screwthreaded section 2~ corresponds to the femalo screwthread of the bore ~8. ~he frustoconical head section 26 need not ~ecessarily e~hibit a precise conical surface, but may also be bevelled or rounded in a different manner ~he head section 26 in the 1~ example illustrated mer~es into a c~lindrical shank 28 o~ any desired le~gth and a head 30 adjoining the latter for the application of a screwdriver or female hexagon key. However, other elements which permit a rotation and a bracing of the tension rod 12 to the left in ~ig. 1 may be provided instead of the shank and of the head 30.
During the assembly of the foundation bolt ~ccording to the invention, the scre~threaded section 2~ iB first of all passed through the anchorage ~ section 16 and screwed into the bore 18, until e~
the conical head section 12 is loos~ely in contact against the right~hand end of the slee~e. In this position the sleeve and the ten~ion rod are introduced as a unit into a bore~ which may be e.g., a bore in a concrete wall or in components made of timber or chip-boards. Box~shaped furniture items may be assembled e.g., by making blind hole~ in a board from each o~
its edges, and drilling holes with a countersink for the head 30 in associated positions of rectangularly ~ 7 --adjacent board~. ~hese possibilities o~ assembly are known per se and will therefore not be explained i~
de-tail.
~ he unit comprising sleeve 10 and tension rod 12 is introduced into the hole until the head 30 abuts against a suitable stop, e.g., the bottom of a sunk hole. ~en the tension rod 12 is further rotated in this position the sleeve 10 is attra¢ted due to the screwthread engagement between the scre~threaded sectlon 2~ and the bore 18 and simultaneously spread, as shown in ~ig. 3. During this spreading the anchor-age section 16 tears open in the region of the grooves 22 (~ig. 2) into individuRl segme~nts 32 (Fig. 2).
'~hese se~ent~ penetrate increasingly into the material of the ad~acent wall of the bore, so that the sleeve becomes anchored in the bore. The position o~ ~ig. 4 is then substantially obtained.
~ he cross-sectional shape of the sleeve 10 according to the invention not only has the advantage that a corotation of the sieeve during the tensioning operation i9 e~cluded. On the contrary, Fig. 4 clearly shows that the individual segments 32 con-stitute a lar~er number of sharp corners than is the case sayl of cylindrical spreadable sleeves. Said sharp corners ~acilitate the penetration into the material of the bore wall and hence the anchorage of the sleeve.
~ he foundation bolt according to the in~ention makes possible, for example, Q corner joint of box-shaped furniture items without fitting parts being visible on the external surface of the individual boards, with the exception of the head 30 let into a sunk bore, which can however if desired be used as a decorative element.
After the anchorage the sleeve 10 attains a fixed seat in the associated bore, which is still retained if the tension rod 12 is unscrewed in order to release the joint and possibly screwed back in again afterwards.
The feature of the grooves 22 being only pre-weakened but not fully broken, is of importance in connection with the feature of a frusto-conical bore in the sleeve. As a consequence of the combination of these two features, the strength of the pre-weakened spreading grooves increases from the rear end to the leading end of the sleeve. Thus, when the frusto-conical head portion of the tension rod is inserted into the sleeve, the spreading lines will grad-ually tear open from their respective rear ends. While, according to the prior art, as exemplified by British patents 725,291 of March 2, 1955 to Ericsson and 335,508 of September 25, 1930 to Wagner, the spreadable sectors of the anchorage section are pivoted about their respective - roots, according to the present invention, because of the gradual tearing open of the spreading lines (grooves), these sections are bent outwardly in an arcuate manner, and r hence, spread to a larger degree, so that anchorage is improved, particularly in soft material such as gas-concrete.
V
Claims (10)
1. An anchor bolt for anchorage in a bore, comprising (a) a tension rod having a male screwthreaded portion terminating in a frusto-conical head portion diverging therefrom; and (b) a sleeve of polygonal cross-section having a female screwthreaded portion for engagement with said male screwthreaded portion of said tension rod, said female screwthreaded portion terminating in a frusto-conical bore diverging therefrom for engagement with said head portion of said tension rod;
(c) axially parallel grooves being provided in the middles of the polygonal sides of said sleeve, the conicity of said frusto-conical bore and the depth of said grooves being so selected that they converge to a substantial degree at the end of said bore remote from said female screw-threaded portion, to provide a sectorally spreadable anchorage section.
(c) axially parallel grooves being provided in the middles of the polygonal sides of said sleeve, the conicity of said frusto-conical bore and the depth of said grooves being so selected that they converge to a substantial degree at the end of said bore remote from said female screw-threaded portion, to provide a sectorally spreadable anchorage section.
2. An anchor bolt as claimed in claim 1, wherein the cross-section of said sleeve is hexagonal.
3. An anchor bolt as claimed in claim 1, wherein said grooves have substantially vee-shaped cross-sections.
4. An anchor bolt as claimed in claim 1, wherein the sleeve is an aluminum injection die-casting.
5. An anchor bolt for anchorage in a bore, comprising (a) a tension rod having a male screw-threaded portion terminating in a frusto-conical head portion diverging therefrom at a first angle of conicity; and (b) a sleeve of polygonal cross-section having a female screw-threaded portion for engagement with said male screw-threaded portion of said tension rod, said female screw-threaded portion terminating in a frusto-conical bore diverging therefrom at a second angle of conicity less than said first angle, for engagement with said head portion of said tension rod;
(c) axially parallel grooves being provided in the middles of the polygonal sides of said sleeve so as to define outwardly cornered segments therebetween, the conicity of said frusto-conical bore and the depth of said grooves being so selected that they converge to a sub-stantial degree at the end of said bore remote from said female screw-threaded portion, whereby, upon engagement of said head portion against said bore, said segments are forced arcuately outwardly by sequential tearing of said grooves from the trailing end to the leading end of said sleeve.
(c) axially parallel grooves being provided in the middles of the polygonal sides of said sleeve so as to define outwardly cornered segments therebetween, the conicity of said frusto-conical bore and the depth of said grooves being so selected that they converge to a sub-stantial degree at the end of said bore remote from said female screw-threaded portion, whereby, upon engagement of said head portion against said bore, said segments are forced arcuately outwardly by sequential tearing of said grooves from the trailing end to the leading end of said sleeve.
6. An anchor bolt as claimed in claim 5, wherein the cross-section of said sleeve is hexagonal.
7. An anchor bolt as claimed in claim 5, wherein said grooves have substantially vee-shaped cross-sections.
8. An anchor bolt as claimed in claim 5, wherein said grooves are provided in the median region of each of said polygonal sides of the said sleeve.
9. An anchor bolt as claimed in claim 5, wherein said grooves extend along the entire length of said sleeve.
10. An anchor bolt as claimed in claim 5, wherein said sleeve is an aluminum injection die-casting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000342487A CA1168484A (en) | 1979-12-21 | 1979-12-21 | Foundation bolt |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000342487A CA1168484A (en) | 1979-12-21 | 1979-12-21 | Foundation bolt |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1168484A true CA1168484A (en) | 1984-06-05 |
Family
ID=4115883
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000342487A Expired CA1168484A (en) | 1979-12-21 | 1979-12-21 | Foundation bolt |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1168484A (en) |
-
1979
- 1979-12-21 CA CA000342487A patent/CA1168484A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |