The subject matter disclosed herein relates to screw-type fasteners. More particularly, the subject invention relates to screw type masonry anchors.
In order to secure fixtures and other attachments to masonry, a screw-type anchor is often used. In anchors of this type, a helical cutting thread is formed on the shank of the anchor and acts to cut and tap the wall of a hole in the masonry when the anchor is turned into the hole, thereby retaining the anchor to the masonry. Typically, the cutting thread has a v-shaped cross-section wherein the flanks of the thread intersect at an included angle of 55-60 degrees. The diameter of a crest of the cutting thread is greater than the diameter of the hole into which the anchor is inserted so the cutting thread cuts the wall of the hole when inserted. In some anchors, multiple cutting threads, each having a crest diameter greater than the hole diameter may be utilized to increase a holding power of the anchor. The art would well receive a masonry screw with further improved holding power to retain attachments to masonry.
According to one aspect of the invention, a masonry anchor includes a head and a body integral to the head and extending therefrom. At least one helical male thread surrounds the body and includes a leading face and a trailing face substantially perpendicular to the body disposed between the leading face and the head. The trailing face intersects the leading face at a thread crest.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
Shown in
A first crest diameter 28 of the first thread 18 and a second crest diameter 30 of the second thread 20 are greater than a diameter of a hole in workpiece (not shown), for example masonry, into which the screw 10 is inserted. Thus, when the screw 10 is turned into the hole, the first thread 18 and second thread 20 cut female threads into the hole to increase a holding capability of the screw 10 in the workpiece. In some embodiments, as shown in
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While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.