Abstract: A double action blind rivet assembly comprising an outer sleeve member with an annular head flange at one end and having an initial outside diameter such that it is receivable through the holes in the workpieces and a length such that it projects from the blind side of the workpieces for the formation of a blind head therein; an inner sleeve member with an annular head flange at one end and having an outside diameter larger than the inside diameter of the outer sleeve member so that, when the inner sleeve member is driven into the outer sleeve member from the accessible side of the workpieces, it will expand the outer sleeve member into a prescribed interference fit by expanding the holes through the workpieces with the inner sleeve member also having a length such that it projects from the blind side of the workpieces after it is driven into the outer sleeve member; and internally supporting the inner sleeve member while it is being driven into the outer sleeve member with a blind head former section thereon

Abstract: A method of forming a fastener joint in a composite material work piece subject to an operating load comprising the steps of forming a hole of a prescribed hole diameter through the composite material work piece placing a tubular metal sleeve member with a compressible cushion layer around the outside thereof within the hole through the work piece; non-elastically expanding the tubular metal sleeve member radially and circumferentially to force the cushion layer into contact with the hole surface and compress the cushion layer; and placing a fastener in the tubular metal sleeve member to maintain the sleeve member radially and circumferentially expanded and the cushion layer compressed to a thickness to transmit the operating load from the work piece to the fastener through the cushion layer and sleeve member. The joint formed by the method is also disclosed.

Abstract: A method of coldworking a hole through a work piece which includes placing a seamless tubular member within the hole with a prescribed hoop strength to allow the tubular member to be expanded and prescribed column strength which prevents axial movement of the outside of the tubular member as the tubular member is expanded, holding the tubular member within the hole so that the tubular member is substantially axially fixed with respect to the hole, and passing an expansion mandrel through the inside of the seamless tubular member to radially and circumferentially expand the tubular member sufficiently to induce a compressive stress gradient of a prescribed magnitude in the material of the work piece substantially uniformly about the entire inside surface of the hole so as to increase the fatigue strength thereof.

Abstract: A reverse taper fastener including a fastner pin portion having a head and an elongate bearing section adapted to extend through holes in the work pieces where the bearing section tapers inwardly from the leading end toward the trailing end of the bearing section; and a pintail portion integrally connected to the leading end of the fastener pin portion through a breakneck section with an expansion section for expanding the holes from a diameter smaller than the bearing section to a diameter larger than same for installing the fastener where the breakneck groove around the breakneck section has been either closed or filled to form a continuous surface between the bearing section and expansion section. The disclosure also comprehends the method of manufacturing the fastener.

Abstract: A reverse taper fastener system including a fastener pin having an elongate bearing section adapted to extend through holes in the work pieces where the bearing section tapers inwardly from the leading end toward the trailing end of the bearing section, having an enlarged head integral with the trailing end of the bearing section, and a pintail section at the leading end of the fastener pin which may carry an expansion collet for expanding the holes from a diameter smaller than the bearing section to a diameter larger than same for installing the fastener. The disclosure also comprehends the method of installing the fastener as well as the method of manufacturing the fastener.

Abstract: A fastener assembly for installation in holes through work pieces including an elongate fastener with a bearing section to be placed in the holes, a pintail releasably connected to the leading end of the fastener to pull the fastener into the holes, and an alignment means such as a locking collet for maintaining the pintail and fastener coaxial during the installation of the fastener.

Abstract: A sleeve member for positioning between the fastener and work pieces within aligned holes through the work pieces. The sleeve member has a tubular side wall with outwardly directed bends formed therein which are partially flattened out during the assembly of the fastener in the work pieces so that the natural resiliency of the sleeve member compensates for discrepancies in the holes and fastener and which may be coated with a sealant prior to assembly so that the bends act as reservoirs for the sealant to insure sealing of the fastener joint.

Abstract: A fastener assembly for installation in holes through work pieces including an elongate fastener with a bearing section to be placed in the holes, a pintail releasably connected to the leading end of the fastener to pull the fastener into the holes, and an alignment means such as a locking collet for maintaining the pintail and fastener coaxial during the installation of the fastener.

Abstract: A preload adapter for use with a lockbit installation gun having a nose assembly to install a fastener having a threaded engagement section to be engaged by an internally threaded nut and a pulling section projecting beyond the threaded engagement section in a hole through a work piece so that the lockbolt installation gun can exert an axial preload on the fastener while the nut is tightened onto the threaded engagement section.

Abstract: A hole expansion mandrel assembly for expanding holes through work pieces including a drive pin with a leading pulling section and a trailing driving shoulder; and a collet removably carried on the drive pin and abutting the driving shoulder where the collet has an expansion surface to enlarge the holes as the drive pin is used to force the collet through the holes. The drive pin may incorporate a fastener trailing the collet. The method of using the apparatus is also contemplated.

Abstract: A reverse taper fastener system including a fastener pin having an elongate bearing section adapted to extend through holes in the work pieces where the bearing section tapers inwardly from the leading end toward the trailing end of the bearing section, having an enlarged head integral with the trailing end of the bearing section, and a pintail section at the leading end of the fastener pin which may carry an expansion collet for expanding the holes from a diameter smaller than the bearing section to a diameter larger than same for installing the fastener. The disclosure also comprehends the method of installing the fastener as well as the method of manufacturing the fastener.

Abstract: A mandrel assembly for expanding holes through work pieces including a helically wound coil member with interconnected helical flights and a support member with the support member supporting the flights of the coil member so that the leadingmost flight has a first effective outside diameter smaller than the initial hole diameter and at least one of the flights trailing the leadingmost flight has a second effective outside diameter larger than the first outside diameter of the leadingmost flight. The support member may be a threaded fastener supporting the flights of the coil member by its threads or have a tapered support section to support the coil member. The method of using the mandrel assembly is contemplated.

Abstract: A split pintail fastener assembly for installation in holes through work pieces including an elongate fastener with a bearing section to be placed in the holes, an engagement section to be engaged to hold the fastener in the holes, and a pintail section connected to the leading end of the engagement section by a frangible breakneck section; a pintail extension coaxially aligned with the leading end of the pintail section on the fastener; and connection means releasably connecting the trailing end of the pintail extension to the leading end of the pintail section on the fastener.

Abstract: A sleeve member for positioning between the fastener and work pieces within aligned holes through the work pieces. The sleeve member has a tubular side wall with outwardly and inwardly directed bends formed therein in an alternating pattern which are partially flattened out during the assembly of the fastener in the work pieces so that the natural resiliency of the sleeve member compensates for discrepancies in the holes and fastener.

Abstract: A fastener/guide assembly and method including a fastener having a head, a bearing section to be extended through aligned holes in work pieces, and an engagement section opposite the head; and a guide member having a pilot section sized to extend through the holes to center the guide member in the holes, an expansion section trailing the pilot section sized to expand the holes, and locating means for locating the leading end of the fastener concentrically about the axis of the guide member so that the fastener follows the guide member through the holes.

Abstract: A joint construction including a plurality of work pieces with aligned holes and with a tubular member in the holes. The tubular member has a major section with a first outside diameter and a minor section with a second outside diameter smaller than the first diameter with both sections defining a substantially constant diameter common central passage therethrough, and has been expanded into contact with the work pieces about the holes to coldwork the work pieces.

Abstract: A method of coldworking a hole through a work piece which includes the steps of placing a seamless tubular member through the hole in the work piece, passing a mandrel through the tubular member so that the tubular member is expanded radially and circumferentially sufficiently to expand the material in the work piece about the hole beyond its elastic limit, and longitudinally fracturing the tubular member after substantially maximum expansion of the tubular member. The application also contemplates a tubular member construction for use in the method and a tool for performing the method.