Fixed Engagement Anchor

Abstract

A novel plastic anchor design allows for the use of a wide range of thread-cutting screw lengths without exceeding the recommended engagement length. In accordance with the principles disclosed herein, an anchor comprises an engagement area and a relief chamber. The anchor is configured to be secured into a surrounding material. The engagement area is configured to engage with a screw to secure the screw when fastening an object in place. The relief chamber receives any excess length of the screw that extends beyond the engagement area. This allows the length of engagement between the screw and the anchor to be controlled for various lengths of screws or thicknesses of objects to be fastened.

Claims

1. An anchor, comprising: an opening; a relief chamber internal to the anchor; and an engagement area between the opening and the relief chamber.

2. An anchor as in claim 1, comprising an anchor head.

3. An anchor as in claim 1, wherein the anchor comprises plastic.

4. An anchor as in claim 1, wherein the anchor comprises a water-tight body.

5. An anchor as in claim 1, further comprising a water-tight seal.

6. An anchor as in claim 1, further comprising one or more exterior structures.

7. An anchor, comprising: a body comprising a channel, the channel comprising: an engagement area with a first cross-sectional diameter; and a relief chamber internal to the body, the relief chamber comprising a second cross-sectional diameter that is larger than the first cross-sectional diameter.

8. An anchor as in claim 7, comprising an anchor head.

9. An anchor as in claim 7, wherein the anchor comprises plastic.

10. An anchor as in claim 7, wherein the anchor comprises a water-tight body.

11. An anchor as in claim 7, further comprising a water-tight seal.

12. An anchor as in claim 7, wherein a cross-section of the engagement area is substantially cylindrical, and a cross-section of the relief chamber is substantially cylindrical.

13. An anchor kit, comprising: an anchor comprising a channel, the channel comprising: an engagement area with a first cross-sectional diameter; a relief chamber with a second cross-sectional diameter that is larger than the first cross-sectional diameter; a screw comprising: a screw head; a threaded portion; wherein a cross-sectional diameter of the threaded portion of the screw is matched to the first cross-sectional diameter.

14. An anchor kit as in claim 13, wherein the anchor comprises an anchor head.

15. An anchor kit as in claim 13, wherein the anchor comprises plastic.

16. An anchor kit as in claim 13, wherein the anchor comprises a water-tight body.

17. An anchor kit as in claim 13, further comprising a water-tight seal.

18. An anchor kit as in claim 13, wherein the anchor comprises an opening with a third cross-sectional area that is smaller than the first cross-sectional area.

19. An anchor kit as in claim 13, wherein the anchor comprises one or more exterior structures.

20. An anchor kit as in claim 13, wherein the screw has a length selected to extend through one or more objects to be fastened, through the engagement area, and only partially into the relief chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The detailed description makes reference to the accompanying figures wherein:

[0021] FIG. 1 illustrates a thread-forming screw and a plastic anchor in accordance with the prior art.

[0022] FIG. 2 illustrates a prior art expanding anchor used with a lag bolt.

[0023] FIG. 3 illustrates a prior art thread-forming screw.

[0024] FIG. 4 illustrates a prior art chemical anchor.

[0025] FIG. 5 illustrates an embodiment of an anchor and a screw in accordance with the principles disclosed herein.

[0026] FIG. 6 illustrates an embodiment of an anchor and a screw with example dimensions.

[0027] FIG. 7 illustrates an embodiment of an anchor in accordance with the principles disclosed herein.

[0028] The figures are only intended to facilitate the description of the principles disclosed herein. The figures do not illustrate every aspect of the principles disclosed herein and do not limit the scope of the principles disclosed herein. Other objects, features, and characteristics will become more apparent upon consideration of the following detailed description.

DETAILED DESCRIPTION

[0029] A detailed illustration is disclosed herein. However, techniques, methods, processes, systems and operating structures in accordance with the principles disclosed herein may be embodied in a wide variety of forms and modes, some of which may be quite different from those disclosed herein. Consequently, the specific structural and functional details disclosed herein are merely representative.

[0030] None of the terms used herein, including “anchor” and “screw,” are meant to limit the application of the principles disclosed herein. Any reference to a screw is exemplary and intended to encompass a screw, bolt, or similar fastener comprising or configured to engage with a helical ridge. Other explicit and implicit definitions may also be included below.

[0031] With reference to FIG. 5, a cross section of anchor 500 shows anchor head 502 and anchor body 504, which comprises a channel with counterbore opening 506, engagement area 508, and relief chamber 510. Screw 514 comprises screw head 514, non-threaded portion 516, and threaded portion 518.

[0032] The mouth of counterbore opening 506 has a diameter that matches the largest diameter of threaded portion 518 and thus guides screw 512 into anchor 500 on the center axis of the channel in the anchor. In some alternative embodiments, a counterbore opening (such as counterbore opening 506) is omitted.

[0033] The engagement area 508 is where screw 512 cuts its threaded portion 518 into the anchor's interior wall. The length of engagement area 508 should be chosen to suit the diameter of screw 512. For example, the Stanley Publication advises that the length of engagement should be 2 to 3 times the nominal screw diameter.

[0034] The relief chamber 510 allows the extra length of screw 512 to move without engaging in the anchor's interior wall. Thus, once the threaded portion 518 of screw 512 has reached the innermost point of engagement area 508, inserting screw 512 further into anchor 500 will not increase the engagement length. Thus, a maximum engagement length may be designed for a given anchor. Relief chamber 510 is shown with a counterbore transition where the chamber meets the engagement area 508, but in some alternative embodiments, a counterbore transition may be omitted.

[0035] Anchors according to the principles disclosed herein may be manufactured using any suitable process. In one example, manufacturing of an anchor comprises molding a solid core, then drilling out a narrow hole with the diameter of the engagement area, drilling out a larger hole from the top to create the top opening, and drilling out a larger hole from the bottom to create the relief chamber. A molded plug is then inserted into the bottom of the anchor and sealed, thereby securing the bottom of the anchor closed.

[0036] FIG. 6 depicts an example (not shown to scale) with dimensions for an anchor 600 and screw 608. Screw 608 is a size M6 screw, which has an outside diameter of the screw threads 610 of 6 mm. The mouth of counterbore opening 602 has a 6 mm diameter which matches the diameter of the screw threads 610. The engagement area 604 has a diameter of 4.8 mm and an engagement length of 12 mm to 18 mm (corresponding to 2 to 3 times the diameter of the 6 mm screw threads). The relief chamber 606 has a diameter of 6 mm and a length of 30 mm or more. In some embodiments, the relief chamber is 110 mm or more.

[0037] The principles disclosed herein may be used to produce anchors of various dimensions. For use in asphalt applications, it is recommended to use anchors configured to receive screws of size M4 up to size M30. An anchor configured to receive a screw smaller than a size M4 may be too weak for an asphalt surface that is driven, rolled, or walked on. At the high end, an anchor configured to receive a screw larger than a size M30 may be uneconomical or otherwise undesirable, as the weakness of the asphalt becomes a limiting factor makes it difficult to justify such a large bolt and large diameter hole.

[0038] An anchor as described herein may comprise any suitable material. Testing has shown that polycarbonate materials are particularly suitable. Compared to polycarbonate alone, an anchor formed of polycarbonate material with 10-30% glass demonstrates an increased ability to withstand large pull and shear forces, but also demonstrates an increased brittleness.

[0039] If water or other liquids enter the interior of an anchor, such as the relief chamber or engagement area of an anchor as disclosed herein, the water or other liquids may weaken the screw by, for example, causing it to rust. Thus, in some embodiments, the interior of the anchor is provided with a water-tight seal to prevent groundwater or other liquids from entering the interior of the anchor. The watertight seal may be naturally formed as a function of the anchor material, such as for anchors consisting of molded plastic. In some embodiments, a pliable washer may be used under the screw head to reduce or prevent water or other liquids from entering the interior of the anchor through the top.

[0040] In some embodiments, an anchor as described herein may incorporate one or more substantially vertical structures on the exterior of the anchor body to better resist torque-out of the anchor from the surrounding material. In some embodiments, an anchor as described herein may incorporate one or more substantially horizontal structures on the exterior of the anchor body to better resist pull-out of the anchor from the surrounding material. Combinations of horizontal and vertical structures may be employed, and other suitable designs may be employed without departing from the principles disclosed herein. For example, FIG. 7 depicts anchor 700 which comprises vertical structures 702 and spiral structure 704.

[0041] A screw may be provided with an anchor or otherwise selected for use with an anchor. Preferably, a screw is chosen with a length that extends through the object(s) to be fastened and leaves enough length in the threaded area to engage with the full length of the engagement area of the anchor but not extend past the length of the relief chamber.

[0042] It is contemplated that a nail may be used with an anchor is accordance with the principles disclosed herein, for example in field applications that involve varying lengths of nails. Providing a relief chamber may reduce the overall effort required to drive the nail in.

[0043] The detailed description is not intended to be limiting or represent an exhaustive enumeration of the principles disclosed herein. It will be apparent to those of skill in the art that numerous changes may be made in such details without departing from the spirit of the principles disclosed herein.