Blind fastener with expandable collar

Claim 2

In a blind fastener for installation in a bore through work material, the combination of: a fastener sleeve of a diameter to enter the bore, said sleeve being divided longitudinally into a main body portion, a collapsible neck portion, and a nut portion at its leading end, the nut portion being formed with an internal screw thread, said body portion being dimensioned in length to occupy the bore with the neck portion and the nut portion extending beyond the far face of the work material, said neck portion being of substantially smaller outside diameter than the body portion and of substantially lesser wall thickness; expansile ring means embracing said neck portion and having an initial outside diameter to pass through said bore, said nut portion being formed with a rearwardly facing outer circumferential driving shoulder to abut the far side of the ring means; and a core bolt to fit into said sleeve from the trailing end of the sleeve for screw engagement with said internal screw thread, said core bolt having a head larger in cross section than the cross section of the trailing end of the sleeve to abut the trailing end of the sleeve to cause longitudinal contraction of the sleeve in response to screw threaded advance of the core bolt into said internal screw thread, said sleeve being cooperative with said ring means to expand the ring means to a greater outside diameter than the inside diameter of the bore in response to longitudinal contraction of the sleeve, whereby the longitudinal contraction of the sleeve by the core bolt collapses said neck portion, expands the ring means and causes said shoulder of the nut means to clamp the expanded ring means against the far side of the work material.

Claim 3

A combination as set forth in claim 1 in which said head of the core bolt is larger in cross section than said bore whereby the head of the bolt engages the near side of the work material as well as the trailing end of the sleeve to anchor the sleeve against axial movement inwardly of the bore.

Claim 4

A combination as set forth in claim 1 in which expansile ring means includes a resilient C-shaped ring of substantially less than 360* circumferential extent whereby the radial outward bulging of the neck portion of the sleeve against the inner circumference of the ring means shifts the ring means radially in addition to expanding the ring means.

Claim 5

A combination as set forth in claim 1 in which said ring means includes a split ring; in which the ends of the split ring are spaced apart by less than the outside diameter of the neck portion for positive engagement with the neck portion; and in which the spreading of the ends of the split ring for assembly of the split ring to the neck portion of the sleeve stresses the split ring within the elastic limits of the split ring.

Claim 6

A combination as set forth in claim 4 in which the expansile ring means comprise a pair of split rings each of greater than 180* circumferential extent bUt of substantially less than 360* circumferential extent, with the two ends of each ring spaced apart by less than the outside diameter of the neck portion of the sleeve for positive engagement with the neck portion.

Claim 7

A combination as set forth in claim 5 in which said rings are positioned with an end of one ring overlapping an end of the other ring, the overlapping end portions being reduced in axial dimension to permit the two rings to be axially coextensive and to form shoulders on the two rings adjacent the overlapping ends to keep the two rings in positions confronting each other.

Claim 8

A combination as set forth in claim 6 in which the second end of each split ring is a blunt end, the two blunt ends of the two split rings confronting each other when the other ends of the two rings overlap each other.

Claim 9

In a blind fastener for installation in a bore through work material, the combination of: a fastener sleeve of a diameter to enter the bore, said sleeve being divided longitudinally into a main body portion, a collapsible neck portion and a nut portion at its leading end formed with an internal screw thread, said body portion being dimensioned in length to occupy the bore with the neck portion and the nut portion extending beyond the far face of the work material, said neck portion being of substantially smaller outside diameter than the body portion and of substantially lesser wall thickness; and expansile ring means embracing said neck portion and having an initial outside diameter to pass through said bore, said nut portion being formed with a rearwardly facing outer circumferential driving shoulder adjacent said neck portion having the ring means disposed thereon to drive the ring towards the body portion, said nut portion being formed with an internal screw thread of a minor diameter less than the inside diameter of the body portion and neck portion of the sleeve, whereby with the body portion of the sleeve positioned in the bore, a core bolt may be inserted into the sleeve from its trailing end into screw engagement with said internal thread and may be tightened against the trailing end of the sleeve to collapse the thinned neck portion of the sleeve longitudinally by forming circumferential folds therein with the folds bulging radially outward, the outward bulging of the folds expanding the ring to greater outside diameter than the inside diameter of the bore and the longitudinal contraction of the neck portion causing the driving shoulder of the nut portion to drive the expanded ring against the far face of the work material.

Claim 10

In a blind fastener for installation in a bore through work material, the combination of: a fastener sleeve of a diameter to enter the bore, said sleeve being divided longitudinally into a main body portion, a collapsible neck portion and a nut portion at its leading end formed with an internal screw thread, said body portion being dimensioned in length to occupy the bore with the neck portion and the nut portion extending beyond the far face of the work material, said neck portion being of substantially smaller outside diameter than the body portion and of substantially lesser wall thickness; and expansile ring means embracing said neck portion and having an initial outside diameter to pass through said bore, said nut portion being formed with a rearwardly facing outer circumferential driving shoulder adjacent said neck portion having the ring means disposed thereon to drive the ring towards the body portion, said nut portion being formed with an internal screw thread of a minor diameter less than the inside diameter of the body portion and neck portion of the sleeve, whereby with the body portion of the sleeve positioned in the bore, a core bolt may be inserted into the sleeve from its trailing end into screw engagement with said internal thread and may be tightened against the trailing end of the sleeve to collapse the thinned neck portion of the sleeve longitudinally by forming circumferential folds therein with the folds bulging radially outward, the outward bulging of the folds expanding the ring to greater outside diameter than the inside diameter of the bore and the longitudinal contraction of the neck portion causing the driving shoulder of the nut portion to drive the expanded ring against the far face of the work material.

Claim 11

A combination as set forth in claim 8 in which said body portion has a circumferential enlargement to engage the work material to resist axial movement of the body portion inwardly of the bore.

Claim 12

A combination as set forth in claim 9 in which said circumferential enlargement of the body portion is in the form of an enlarged rim at the rear end of the body portion of the sleeve, the outside diameter of the rim slightly exceeding the inside diameter of the bore whereby driving the enlargement into the bore anchors the sleeve in the bore.

Claim 13

A combination as set forth in claim 10 in which said rim is formed with longitudinal serrations to bite into the wall of the bore.

Claim 14

A combination as set forth in claim 9 in which said circumferential enlargement has a smooth tapered leading shoulder for wedging action in the bore.

Claim 15

A combination as set forth in claim 12 in which said circumferential enlargement is at the rim of the trailing end of the sleeve.

Claim 16

A combination as set forth in claim 12 in which said circumferential enlargement is at a point intermediate the length of the body portion of the sleeve.

Claim 17

A combination as set forth in claim 8 in which the near end of the bore is counterbored to form an annular recess around the bore on the inner face of the work material; which includes a deformable ring to seat in said annular recess; and in which said body portion of the sleeve is formed with a circumferential enlargement in the form of an enlarged rim at the trailing end of the sleeve, said annular recess, deformable ring and circumferential enlargement being shaped and dimensioned to cause the enlargement to compress the deformable ring radially in the annular recess to anchor the sleeve against rotation and to cause the enlargement to seat against the bottom of the recess when the sleeve is forcibly driven into its installed position in the bore.

Claim 18

A combination as set forth in claim 15 in which said circumferential enlargement is formed with longitudinal serrations to bite into the deformable ring.

Claim 19

A combination as set forth in claim 15 in which said circumferential enlargement is formed with a tapered leading shoulder for wedging action against the deformable ring.

Claim 20

A combination as set forth in claim 8 in which said body portion is without screw threads.

Claim 21

A combination as set forth in claim 8 in which the inner circumference of said nut portion of the sleeve is deformed for self-locking cooperation with the core bolt.

Claim 22

A combination as set forth in claim 8 in which the combination includes the core bolt.

Claim 23

A combination as set forth in claim 20 which includes a second larger core bolt to be substituted for the first core bolt to anchor an object to the work material after the sleeve is contracted by the first core bolt.

Claim 24

A combination as set forth in claim 20 in which said core bolt has a head of larger cross sectional dimension than the bore for tightening action against the rim of the bore as well as against the trailing end of the sleeve.

Claim 25

A combination as set forth in claim 8 in which said sleeve is dimensioned in length for use in a bore of a relatively short axial dimension; and which includes an auxiliary sleeve in abutment with the trailing end of the fastener sleeve, said auxiliary sleeve being of a length to cooperate with the fastener sleeve in a bore longer than said given bore, whereby auxiliary sleeves of various lengths may be used interchangeably to adapt the fastener for use in bores of various lengths.

Claim 26

A combination as set forth in claim 8 in which said neck portion is formed with a tapered external enlargement of less outside diameter than the inside diameter of the bore for expanding cam action on the ring in response to axial contraction of the neck portion.

Claim 27

A combination as set forth in claim 24 in which said external enlargement is a rib of V-shaped cross section.

Claim 28

A combination as set forth in claim 8 in which the neck portion of the sleeve is formed with a circumferential enlargement of an outside diameter less than the inside diameter of the bore, said enlargement having a tapered leading shoulder for expanding cam action on said ring, said enlargement having an abrupt trailing shoulder.

Claim 29

A combination as set forth in claim 8 in which the thickness of the wall of the neck portion of the sleeve increases by stages towards the body portion of the sleeve whereby the neck portion collapses by stages with the first stage causing initial expansion of said ring means.

Claim 30

A combination as set forth in claim 27 in which said first stage is shaped and dimensioned to serve primarily to expand the ring means, the next stage serving to permit final longitudinal contraction of the neck portion to force the expanded ring against the far face of the work material.

Claim 31

A combination as set forth in claim 28 in which said expansile ring means comprises split ring means.

Claim 32

A combination as set forth in claim 8 in which said ring means includes a split ring which is sufficiently resilient to resist expansion by the neck portion whereby the expanded ring means presses the folded neck portion inwardly for locking action on the core bolt.

Claim 33

A combination as set forth in claim 8 in which said ring means comprises two split rings each of greater extent than 180*, said two ringS having one pair of abutting ends and one pair of overlapping ends.

Claim 34

A combination as set forth in claim 1 in which the bore has a flared entrance and the core bolt has a conical head which seats in the flared entrance substantially flush with the near face of the work material.

Claim 35

A combination as set forth in claim 1 in which at least a portion of the sleeve is tapered longitudinally to cause the sleeve to wedge into the bore to hold the sleeve against rotation relative to the work material.

Claim 36

A combination as set forth in claim 33 in which the sleeve is tapered over substantially the whole length of the main body portion of the sleeve.

Claim 37

A combination as set forth in claim 34 in which the bore is tapered.

Claim 38

In a blind fastener for installation in a bore of a workpiece, the combination of: a fastener body of an outside diameter to fit into the bore, said body having a longitudinal passage therethrough, the inner leading end portion of said passage being formed with an internal screw thread and the remainder of the passage having a diameter at least as large as approximately the major diameter of said internal screw thread, an intermediate portion of the body being reduced in thickness to form a neck with a wall thin enough to collapse and crumple in response to substantial longitudinal contraction force, said neck forming a forwardly facing outer circumferential shoulder and a rearwardly facing outer circumferential shoulder, at least one of said two outer circumferential shoulders being externally tapered towards the neck; an externally threaded pull member to fit into said passage from the trailing end thereof for screw engagement with said internal screw thread to exert longitudinal contraction force on the body; and ring means embracing said neck in abutment with said rearwardly facing outer circumferential shoulder and having an initial outside diameter less than the inside diameter of the bore, said ring means being expansile to engage the workpiece in response to the longitudinal contraction of the body and collapse of said neck by the pull member.

Claim 39

In a blind fastener for installation in a bore of a workpiece, the combination of: a fastener body of an outside diameter to fit into the bore, said body having a longitudinal passage therethrough, the inner leading end portion of said passage being formed with an internal screw thread and the remainder of the passage having a diameter at least as large as approximately the major diameter of said internal screw thread, an intermediate portion of the body being reduced in thickness to form a neck with a wall thin enough to collapse and crumple in response to substantial longitudinal contraction force, said neck forming a forwardly facing outer circumferential shoulder and a rearwardly facing outer circumferential shoulder, at least one of said two outer circumferential shoulders being externally tapered towards the neck; an externally threaded pull member to fit into said passage from the trailing end thereof for screw engagement with said internal screw thread to exert longitudinal contraction force on the body; and ring means embracing said neck in abutment with said rearwardly facing outer circumferential shoulder and having an initial outside diameter less than the inside diameter of the bore, said ring means being expansile to engage the workpiece in response to the longitudinal contraction of the body and collapse of said neck by the pull member.

Claim 40

A combination as set forth in claim 36 in which said pull member has an enlargement greater than the diameter of said passage to create force against the trailing end of the body for the purpose of creating said longitudinal contraction force.

Claim 41

A combination as set forth in claim 36 in which the body is shaped and dimensioned to seat in the bore in engagement with the workpiece when forced axially into the bore with the engagement effective to resist rotation of the body relative to the workpiece in reaction to the threading of the pull member into said internal screw thread.