Expansion plug for securing fastening elements

Abstract

An expansion sleeve for securing fastening elements, such as screws, into a wall, comprises a substantially cylindrical sleeve having an insertion end with a front portion adjacent said insertion end with an exterior surface tapering inwardly toward this end and with a plurality of outwardly extending sawtooth projections extending along the longitudinal length thereof adjacent this end. The expandable plug has a closed neck adjacent the opposite end and it includes at least one longitudinal slot and preferably one on each diametrical side extending along a substantial portion of its length from the insertion end to the solid cylindrical sleeve portion. A thickening strip extends longitudinally along preferably each diametric side on sides opposite to the slot sides and they are also provided with a series of longitudinally spaced sawtooth projections. The exterior surface of the expandable plug is provided with a recess along the base or juncture of the thickening strips to the expandable plug in order to permit the thickening strips to pivot during insertion in a direction to cause them to collapse against the side of the expandable plug body. Preferably, a web is provided to hold the front end portions together in the front end area where the slots permit separation of the end portions into two separate parts. The trailing end of the device advantageously includes wedge-shape fins which extend outwardly from the solid sleeve portion. In the preferred arrangement, the thickening strips extend substantially radially outwardly at diametrically opposite sides and they are undercut at their base by the recess formed along the length of the expandable plug adjacent the strips.

Dependencies are inferred from the claim text.