Anchoring screw with double heads and triple threads of different depths of thread

摘要

An anchoring screw with double heads and triple threads of different depths of thread mainly includes a polygonal flange (or a polygonal sunken cavity) formed on the screw for fastening use. The screw has an upper section and a lower section forming respectively two bolts which have different screw thread specifications. One of the bolts has at least triple threads equally spaced from one another. The triple threads have different depths of thread. Thus the bolt of triple threads can provide an effective balance function when fastened into a construction hole to maintain a firm fastening without skewing. The screw threads of different depths of thread can also gather extruded cement debris when the screw is fastened into the construction hole to produce a stronger fastening effect. As there is no expansion incurred, the wall or board does not crack. Therefore the interval between the construction holes may be shortened, and number of construction holes may be effectively increased in a given unit area. The anchoring screw of the invention also may be removed easily and conveniently to facilitate construction.