Chemical self-tapping, screw-type masonry anchor

摘要

A self-tapping, screw-type masonry anchor turnable into a hole drilled in masonry to fasten an object thereto, the anchor also being capable of being chemically retained in the hole to render it exceptionally resistant to pull out and vibratory forces. The anchor includes a head engageable by a tool to turn the anchor into the hole and a shank extending from the head surrounded by at least one helical cutting thread whose crest diameter exceeds the hole diameter whereby as the anchor is turned into the hole, a mating thread is then tapped in its bank. Also surrounding the shank in the space between successive convolutions of the thread is a helical zone. The shank of the anchor is coated with a release agent, and when a charge of an uncured, flowable resinous adhesive is deposited in the hole and the shank is turned therein, this adhesive then fills the helical zone, the flowable adhesive acting to lubricate and cool the cutting thread as the shank is turned into the hole. When the adhesive cures and hardens, a chemical barrier is formed in the zone which is bonded to the bank of the hole but not to the shank. Thus the anchor is mechanically retained in the hole by the cutting thread and chemically retained therein by the hardened barrier, yet the anchor can be turned out of the hole to unfasten the object from the masonry.