Screw-type anchor
A self-tapping masonry anchor includes an axial bore that is formed at one end and extends through a portion of the anchor.
1. A compact anchor for embedding in a pre-drilled masonry or concrete hole comprising:
a forward end and an opposite rear end defining an axial length;
an external helical cutting thread for tapping the masonry or concrete hole;
a solid portion extending from approximately the forward end towards the rear end for at least part of the length of the anchor;
a hollow portion extending from the rear end towards the forward end for at least part of the length of the anchor, the hollow portion comprising:
(a) a threaded fixture attaching portion configured and adapted to secure a structure to the anchor, and
(b) a tool engagement portion adjacent the fixture attaching portion, the tool engagement portion configured and adapted to engage an anchor inserting tool for providing rotational torque to the anchor;
an axially-broad arcuate land having a radial height and disposed between successive rows of the helical cutting thread for wedging the anchor into the pre-drilled masonry or concrete hole, the land having an axial length at least twice its height and configured to abrade the hole for wedging the anchor therein when inserted; and a valley disposed on either side of the land between the land and the cutting thread defining a root diameter to axially space apart the land and the cutting thread.
2. The anchor of claim 1 , wherein the tool engagement portion is configured as a female hex socket.
3. The anchor of claim 1 , wherein the fixture attaching portion is disposed adjacent to and penetrates the rear end of the anchor.
4. The anchor of claim 3 , wherein the cutting thread does not extend over the fixture attaching portion.
5. The anchor of claim 1 , wherein the anchor is formed by cold forging.
6. The anchor of claim 1 , wherein the axial length being less than three times the root diameter of the anchor.
7. The anchor of claim 1 , further comprising the fixture attachment portion and tool engagement portion each having a diameter, the diameter of the fixture attachment portion being larger than the diameter of the tool engagement portion.
8. The anchor of claim 1 , wherein the forward end of the anchor has a blunt shape with a flat forward surface.
9. The anchor of claim 1 , wherein the cutting thread makes less than two helical convolutions around the circumference of the anchor.
10. The anchor of claim 1 , wherein the cutting thread extends over the solid portion and tool engagement portion.
11. The anchor of claim 1 , wherein the cutting thread is formed by cold rolling.
12. The anchor of claim 1 , wherein the fixture attachment portion has a smooth external surface without any threading.
13. A compact anchor in combination with a pre-drilled masonry or concrete hole having a predetermined diameter, the combination comprising:
a forward end and an opposite rear end defining an axial length;
an external helical cutting thread for tapping the masonry or concrete hole, the thread having a diameter larger than the diameter of the hole;
a solid portion extending from approximately the forward end towards the rear end for at least part of the length of the anchor;
a hollow portion extending from the rear end towards the forward end for at least part of the length of the anchor, the hollow portion comprising:
(a) a threaded fixture attaching portion configured and adapted to secure a structure to the anchor, and
(b) a tool engagement portion adjacent the fixture attaching portion, the tool engagement portion configured and adapted to engage an anchor inserting tool for providing rotational torque to the anchor, and
an axially-broad arcuate land disposed between successive rows of the helical cutting thread for wedging the anchor into the pre-drilled masonry or concrete hole a valley disposed on either side of the land between the land and the cutting thread defining a root diameter to axially space apart the land and the cutting thread the land having an axial length at least twice its height and a diameter which is sized to be installed into the masonry or concrete hole.
14. The anchor of claim 13 , further comprising a flat shank portion on either side of the land.
15. The anchor of claim 13 , further comprising the rear end of the anchor being approximately flush with or recessed below an entrance of the hole in the masonry or concrete.
16. The anchor of claim 13 , wherein the tool engagement portion is configured as a female hex socket.
17. The anchor of claim 13 , wherein the fixture attaching portion is disposed adjacent to and penetrates the rear end of the anchor.
18. The anchor of claim 13 , wherein the axial length being less than three times the root diameter of the anchor.
19. The anchor of claim 13 , further comprising the fixture attachment portion and tool engagement portion each having a diameter, the diameter of the fixture attachment portion being larger than the diameter of the tool engagement portion.
20. The anchor of claim 13 , wherein the cutting thread makes less than two helical convolutions around the circumference of the anchor.