Shallow undercut concrete anchor

Patent metadata

Field	Value
Publication number	US-11111941-B2
Application number	US-201815979613-A
Country	US
Kind code	B2
Filing date	May 15, 2018
Priority date	Dec 9, 2015
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

A concrete anchor capable of resisting large loads while requiring minimal embedment depth. The system includes a concrete structure including a cylindrical opening in the concrete surface thereof. The system also uses an anchor which includes a sleeve and a plug. The sleeve includes at least two legs extending toward a first end of the sleeve. The plug includes an increasing diameter portion disposed toward a first end of the plug. The plug includes a locking opening. After installation, legs of the sleeve extend radially outward past the wall and the increasing diameter portion prevents inward movement of the legs to lock the sleeve and the plug in turn in the concrete cylindrical opening. Furthermore, dynamic loading on the plug via the locking opening when the anchor is in use generates a dynamic radially outward force on the legs to secure the anchor in the concrete hole.

First claim

The invention claimed is:

1. An anchor for securing an object to a precast concrete structure, the precast concrete structure including a cylindrical opening in a surface of the concrete structure and the precast concrete structure further including an elongated tension member passing through the precast concrete structure, the elongate tension member further including ends secured to the precast concrete structure, the anchor comprising:
a sleeve and a plug, the sleeve and plug sharing a central longitudinal axis,
the sleeve including at least two legs extending toward a first end of the sleeve and the sleeve also including a second end opposite the first end, the sleeve further including a cylindrical through opening from the first end to the second end,
the plug including a first end for engaging the legs and a second end opposite the first end, the plug received in the cylindrical through opening along the central longitudinal axis, the plug further including a locking portion for connecting the anchor to the object,
a tapered portion disposed on at least one of the plug and the legs,

wherein when the plug and sleeve are forced telescopically relative to each other along the central longitudinal axis, the tapered portion forces the legs to expand radially outward, and
wherein the sleeve is ¾ inches or less in the longitudinal direction and the plug is ¾ inches or less in the longitudinal direction.

2. The anchor of claim 1 , wherein a pull out load applied to the locking portion initiates a radially outward force on the legs.

3. The anchor of claim 1 , wherein the concrete cylindrical opening includes a cylindrical wall having a radius and having a depth of approximately ¾ inches or less, the anchor via the first ends of the sleeve and plug being received in the concrete cylindrical opening to approximately the depth.

4. The anchor of claim 1 , wherein in a collapsed, installed configuration, the anchor has a dimension in the longitudinal direction of about ¾ inches or less.

5. The anchor of claim 1 , wherein the locking portion is a threaded opening.

6. The anchor of claim 1 , further including a threaded rod,
wherein the threaded rod includes a first end and a second end and the first end is couplable to a threaded opening in the plug, and
wherein a load applied to the threaded rod at the second end in an axial direction away from the concrete opening applies a direct radially outward force from the plug to the legs.

7. The anchor of claim 1 , wherein the concrete structure is in the form of a slab, and wherein the slab includes a thickness, T in inches and the ratio of the thickness T to an anchor embedment depth, in inches, in the concrete cylindrical opening is greater than T.

8. The anchor of claim 1 , wherein the anchor is capable of developing a tensile capacity of about 455 lbs in a cracked-concrete condition according to national code, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi.

9. The anchor of claim 1 , wherein the anchor is capable of developing a shear capacity of about 985 lbs in a cracked-concrete condition according to national code, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi.

10. The anchor of claim 1 , wherein the anchor is capable of developing a tensile capacity of about 410 lbs in a seismic condition according to national code, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi.

11. The anchor of claim 1 , wherein the anchor is capable of developing a shear capacity of about 895 lbs in a seismic condition according to national code, in a base material comprised of normal-weight concrete with a compressive strength of about 2500 psi.

12. A method of installing an anchor in a post tensioned concrete structure comprising the steps of:
providing a post tensioned concrete structure including a concrete surface,
drilling a cylindrical opening in the concrete surface, the opening having a depth of 0.75 inches or less,
the concrete cylindrical opening further including an open end and a closed end and a cylindrical wall having a radius, and
providing an anchor including a sleeve and a plug,
the sleeve including at least two legs extending toward a first end of the sleeve and the sleeve also including a second end opposite the first end, the sleeve further including a cylindrical through opening from the first end to the second end,
the plug including a first end for engaging the legs and a second end opposite the first end, the plug received in the cylindrical through opening, the plug further including a locking portion for connecting the anchor to the object,
a tapered portion disposed on at least one of the plug and the legs,

inserting the first ends of the sleeve and plug into the concrete cylindrical opening at a depth from the surface of no more than 0.75 inches, and
forcing the plug and sleeve telescopically relative to each other so that the legs are forced radially outward, and so that the tapered portion prevents inward movement of the legs to lock the sleeve and the plug to the wall of the concrete cylindrical opening.

13. The method of claim 12 , where in the step of providing an anchor including a sleeve and a plug is the step of providing an anchor with a sleeve and a plug each having a longitudinal dimension of ¾ inches or less.

14. An anchor system for securing an object to a structure comprising in combination:
a concrete structure including a concrete cylindrical opening in a surface thereof, the concrete cylindrical opening including an open end and a closed end, and
a anchor including a sleeve and a plug,
the sleeve including at least two legs extending toward a first end of the sleeve and the sleeve also including a second end opposite the first end, the sleeve further including a cylindrical through opening from the first end to the second end,
the plug including a first end for engaging the legs and a second end opposite the first end, the plug received in the cylindrical through opening, the plug further including a locking portion for connecting the anchor to the object,
a tapered portion disposed on at least one of the plug and the legs,

wherein when the plug and sleeve are forced telescopically relative to each other, the legs are forced radially outward as a result of the tapered portion.

15. The anchor system of claim 14 , wherein the concrete cylindrical opening includes a cylindrical wall having a radius and having a depth of approximately ¾″ or less, the anchor via the first ends of the sleeve and plug being received in the concrete cylindrical opening to approximately the depth.

16. The anchor system of claim 14 , wherein a leg of the sleeve extends radially outward past the wall and the tapered portion preventing inward movement of the legs to lock the sleeve and the plug in turn in the concrete cylindrical opening.

17. The anchor system of claim 14 , wherein the concrete structure is a post tensioned concrete structure.

18. The anchor system of claim 17 , wherein the post tensioned concrete structure includes a wire passing through the structure, tension in the wire being applied primarily at ends of the wire.

19. The anchor system of claim 18 , further including a mechanism for adjusting the tension of the wire.

20. The anchor of claim 14 , wherein the locking portion is located on the plug and a pull out load applied to the locking portion translates into a radially outward fo

Assignees

• Black & Decker Inc

Inventors

• Pregartner Thilo
• Cerbone Mark
• Chamberlain Matthew

Classifications

• F16B13/0825

  with a locking element, e.g. sleeve, ring or key co-operating with a cammed or eccentrical surface of the dowel body · CPC title

• F16B13/0858 Primary

  with an expansible sleeve or dowel body driven against a tapered or spherical expander plug (F16B13/004 takes precedence) · CPC title

• E04B5/32

  Floor structures wholly cast in situ with or without form units or reinforcements · CPC title

• E04B2103/02

  of ceramics, concrete or other stone-like material · CPC title

• F16B13/06

  combined with expanding sleeve {(F16B13/045 and F16B13/08 take precedence)} · CPC title