Hole plug fasteners

Claim 2

A three-piece hole plug fastener comprising a headed mandrel, a radially expansible clamping member mounted on the mandrel adjacent to its head, the clamping member being formed with at least two pairs of opposed circumferential slots, and a cap on the mandrel and having a sealing surface adapted for engaging a work surface about a hole therein to be plugged, said opposed circumferential slots defining symmetric, circumferentially tapering wings of different circumferential curvature facilitating radial expansion of the member upon relative retraction of the mandrel head toward the cap.

Claim 3

A pull-to-set hole plug fastener comprising, in coaxial relation, a sealing cap of diameter larger than a hole in a work piece to be plugged thereby, a hollow, axially collapsible, and radially enlargeable member initially insertable into the hole, and a pulling mandrel having a stem axially extending through the cap and having a head projecting beyond the member from the cap, said member being formed from generally flat, rectangular bendable sheet metal having a central portion provided with an aperture for receiving the stem of said mandrel, the central portion being flanked by opposed integral pairs of wings longitudinally spaced and shaped by laterally extending cut-out portions for circumferential forming, the pair of terminal wings being adapted to be secured to opposed portions of one side of the cap, the arrangement being such that, upon relative movement together of the cap and the mandrel head, radially opposed portions of the member are buckled into clamping relation with the work piece.

Claim 4

A pull-to-set hole plug fastener comprising, in coaxial relation, a sealing cap of diameter larger than a hole in a work piece to be plugged thereby, a hollow, axially collapsible, and radially enlargeable member initially insertable into the hole, and a pulling mandrel having a stem axially extending through the cap and having a head projecting beyond the member from the cap, said member being formed from generally flat, rectangular bendable sheet metal having a central portion provided with an aperture for receiving the stem of said mandrel, the central portion being flanked by opposed integral pairs of wings longitudinally spaced and shaped by laterally extending cut-out portions for circumferential forming, the pair of terminal wings being adapted to be secured to opposed portions of one side of the cap, the arrangement being such that, upon relative movement together of the cap and the mandrel head, radially opposed portions of the member are buckled into clamping relation with the work piece.

Claim 5

A blind fastener for plugging a hole in sheet metal or the like comprising, a cap larger than the hole for abutting the sheet metal substantially in hole-stopping relation, a partly tubular domed member having all initial diameters smaller than the hole for insert therethrough except for terminal portions secured to the blind side of the cap, transverse sections of the dome and body portions of the member being generally elliptic, and a headed mandrel projecting through the cap and member and relatively retractable to cause the mandrel head to engage the dome portion of said member and thereby effect radial expansion and axial collapse of certain of said body portions into clamping relation with the sheet metal and said cap, the mandrel having its stem engageable frictionally with the wall of an aperture in the cap to retain the head of the mandrel in external engagement with the domed portion of said member, the mandrel stem being formed with an axial flat for plugging the cap aperture during mandrel retraction, and said mandrel stem being formed adjacent to its flat with a frangible portion sufficiently strong to transmit tension for effecting said collapse of the body portions and thereafter break upon urging said body portions into clamping relation with the sheet metal.

Claim 6

A blind fastener for plugging a hole in sheet metal or the like comprising, a cap larger than the hole for abutting the sheet metal substantially in hole-stopping relation, a partly tubular domed member having all initial diameters smaller than the hole for insert therethrough except for terminal portions secured to the blind side of the cap, transverse sections of the dome and body portions of the member being generally elliptic, and a headed mandrel projecting through the cap and member and relatively retractable to cause the mandrel head to engage the dome portion of said member and thereby effect radial expansion and axial collapse of certain of said body portions into clamping relation with the sheet metal and said cap, the mandrel having its stem engageable frictionally with the wall of an aperture in the cap to retain the head of the mandrel in external engagement with the domed portion of said member, the mandrel stem being formed with an axial flat for plugging the cap aperture during mandrel retraction, and said mandrel stem being formed adjacent to its flat with a frangible portion sufficiently strong to transmit tension for effecting said collapse of the body portions and thereafter break upon urging said body portions into clamping relation with the sheet metal.