Double Collar Wedge Anchor
A solid masonry and hollow block fastening device that uses two expansion collars to secure a fastening thereof in varied masonry materials. In greater particularity, the two expansion collars are interconnected by a bridge of a unitary construction therewith in order to enhance the strength and holding power thereof when mounted on masonry material.
Masonry and concrete fastening device comprising an expansion dowel including an axially extending anchor bolt having a leading wedge anchor and a trailing wedge anchor in an axial tandem arrangement, each said wedge anchor having frustoconical portions widening towards the lower end of said expansion dowel and having cylindrical segments at the smaller and larger ends of each of said wedge anchor, a contacting structure comprising a pair of spaced collars extending one about each respective cylindrical segment at the smaller ends of the wedge anchor and a web member extending between said collars integrally formed therewith so as to form a bridge structure connecting said wedge anchor; a flat-like groove being formed in the surface of the cylindrical segment at the larger end of the trailing wedge anchor and contiguous frustoconical surface thereof, said bridge structure being receivable in said groove so as to inhibit any relative rotation between said wedge anchor during expansion of said dowel into an operative condition.
The present invention relates to a solid masonry and hollow block fastening device that uses two expansion collars to secure a fastening thereof in varied masonry materials. In greater particularity, the two expansion collars are interconnected by a bridge of a unitary construction therewith in order to enhance the strength and holding power thereof when mounted on masonry material.
Moreover, a web element in the form of a bridge connecting two tapers on a pair of wedge anchor located on an expansion dowel is also disclosed in Herb. The provision of two wedge anchor that are interconnected by a web or bridge imparts a greater degree of anchoring strength to the overall expansion dowel. Nevertheless, the employment of a plurality of discrete or separate components forming the bridging connections between the two wedge anchor limits the increase in strength in comparison with the use of only a single tapered wedge anchor when deployed in masonry materials. Although, both of these patents seem to fulfill their intended functions, they are subject to limitations as to their strengths in forming fastening devices employed in solid masonry anchoring and securing applications.
Further publications which are concerned with different types of masonry anchoring and fastening devices which discloses the structure of an expansion or spreader bolt for well fitting, that incorporates three wedge anchor each encompassed by a separate expandable sleeve member.
In order to improve upon the capabilities of tapered wedge anchor as are currently known, the present invention provides for a metal collar or ring-shaped member that extends about each respective taper of a pair of spaced wedge anchor, wherein the collars are connected by means of a bridge that is constructed integral with the collars. Moreover, in order to eliminate relative rotation between the wedge anchor, a flat or groove is cut into one of the wedge anchor for receiving the bridge, as elucidated more specifically hereinbelow.
In masonry materials that are less than 3000 psi, such as brick, cinder block and grout filled block, the torque requirement necessary to install the anchor could cause a rotation problem. The resistance of the masonry is not sufficient to capture the collars of the anchor and, consequently, the anchor will rotate in the hole and the collars will not expand. For this reason, wedge anchor are normally not recommended for use in masonry materials less than 3000 psi. This shortcoming is overcome by using a collar material that is soft or dead soft, whereby this reduces the torque requirement and, in turn, the collars will easily expand.
Tests have shown the inventive double-wedge bridge design to provide for holding powers up to 50% greater than single wedge anchor. The failure mode has consistently been masonry failure. Greater holding power and virtually no slippage render this inventive anchor design ideal for use in areas that are prone or susceptible to seismic disturbances; such as earthquakes.
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