Abstract A mandrel-rivet of the pull-to-set type comprises an mandrel head either adapted, or not adapted, to form the installation hole by rotation relative to a workpiece, and its mandrel stem and/or the barrel portion of the rivet are of a configuration to provide space for holding a dormant sealant or adhesive. Rotation of the mandrel relative to the rivet after drilling may provide a melting or curing heat, and subsequent retraction of the mandrel head for rivet setting simultaneously squeezes the sealant through holes in the rivet barrel into the interface region of the joint to provide greater strength and a water-tight seal. A particularly desirable variant contemplates inclusion of a twopart epoxy initially retained in the barrel and divided by the shape of the mandrel section, for instance oval, until the mandrel rotation relative to the rivet will mix the epoxy whereupon the mandrel retraction secures the rivet while exuding activated adhesive for sealing its joint. A drilling-pulling mandrel stem optionally useful in the fastener for attaining so-called flush break joints would be formed with multiple indentations which, though not likely to cause the stem to break under rotary drilling or straight pulling, would cause its rupture where desired when subjected by the installing tool, after rivet setting, to the tensile stress of the pulling and additionally to a tilting of the stem.
A pull-to-set mandrel-rivet comprising, in telescoping relation, a tubular rivet having a barrel formed with a flange on one end and a radial orifice spaced therefrom, a mandrel provided with a head remote from the flange and having a shank extending through the barrel, that portion of the shank within the barrel having a roughly oval cross section to provide two storage spaces bounded by the inner wall of the barrel, and an epoxy resin and its activator respectively occupying said spaces, said orifice enabling the resin and the activator, upon relative upsetting movement of the mandrel and rivet, to flow and mix to form a sealant for the rivet.
Claim 2
Dependent Claim
110 words
A pull-to-set mandrel-rivet comprising, in telescoping relation, a tubular rivet having a barrel formed with a flange on one end and a radial orifice spaced therefrom, a mandrel provided with a head remote from the flange and having a shank extending through the barrel, that portion of the shank within the barrel having a roughly oval cross section to provide two storage spaces bounded by the inner wall of the barrel, and an epoxy resin and its activator respectively occupying said spaces, said orifice enabling the resin and the activator, upon relative upsetting movement of the mandrel and rivet, to flow and mix to form a sealant for the rivet.
Claim 3
Dependent Claim
48 words
A mandrel-rivet as in claim 1 wherein the mandrel is formed with a drill tip, and operation of the drill tip in forming a work hole for the reception of the mandrel-rivet facilitates the subsequent admixture of the resin and its activator by supplying heat due to friction.