Blind fastener
A reusable blind fastener including a bushing, a nut, a tail, a receiver, an expansion device, and a screw. The expansion device having an exterior surface that is discontinuous and configured for selective elastic deformation when engaging a portion of the screw.
1. A reusable blind fastener, comprising:
a bushing ( 100 ), a nut ( 200 ), a tail ( 300 ), a receiver ( 400 ), an expansion device ( 500 ), and a screw ( 600 );
the bushing ( 100 ) having a bushing distal end ( 102 ), a bushing proximal end ( 104 ), a bushing length ( 106 ) between the bushing distal end ( 102 ) and the bushing proximal end ( 104 ), and a bushing bore ( 110 ) extending through the bushing ( 100 ) from the bushing distal end ( 102 ) to the bushing proximal end ( 104 ), wherein the bushing bore ( 110 ) has a bushing bore longitudinal axis, and a bushing bore diameter ( 118 );
the nut ( 200 ) having a nut distal end ( 202 ), a nut proximal end ( 204 ), a nut length ( 206 ) from the nut distal end ( 202 ) to the nut proximal end ( 204 ), a nut bore ( 210 ) having a nut bore longitudinal axis;
the tail ( 300 ) extending from the bushing ( 100 ), and having a tail distal end ( 302 ), a tail proximal end ( 304 ), a tail length ( 306 ) between the tail distal end ( 302 ) and the tail proximal end ( 304 ), a tail dextral wall ( 310 ), a tail sinistral wall ( 312 ), and a tail width ( 314 ) measured along an exterior surface of the tail ( 300 ) in a direction perpendicular to the bushing bore longitudinal axis;
the receiver ( 400 ) is formed in the nut ( 200 ) and having a receiver distal end ( 402 ), a receiver proximal end ( 404 ), a receiver dextral wall ( 410 ), a receiver sinistral wall ( 412 ), and a receiver width ( 414 ) between the receiver dextral wall ( 410 ) and the receiver sinistral wall ( 412 ) in a direction perpendicular to the nut bore longitudinal axis;
the expansion device ( 500 ) having an ED exterior surface ( 510 ) that is discontinuous and having an initial sinistral gap opening point ( 527 A) and an initial dextral gap opening point ( 527 B), which define an ED initial exterior surface gap angle ( 526 ), wherein the expansion device ( 500 ) has an initial undeformed state with an ED initial max dimension ( 518 ) and the ED initial exterior surface gap angle ( 526 ), and an expanded state with an ED expanded max dimension ( 520 ) greater than the ED initial max dimension ( 518 ) whereby the initial sinistral gap opening point ( 527 A) and the initial dextral gap opening point ( 527 B) have spread apart to an expanded sinistral gap opening point ( 529 A) and an expanded dextral gap opening point ( 529 B), which define an ED expanded exterior surface gap angle ( 528 ) greater than the ED initial exterior surface gap angle ( 526 );
the screw ( 600 ) having a threaded portion ( 620 ), and a transition ( 630 ) adjacent the threaded portion ( 620 ), wherein the transition ( 630 ) has a transition angle ( 640 );
wherein the screw ( 600 ) extends through the bushing ( 100 ) via the bushing bore ( 110 ), the expansion device ( 500 ) is received over the screw ( 600 ), and the nut bore ( 210 ) engages the screw threaded portion ( 620 ), such that rotation of the screw ( 600 ) draws the nut ( 200 ) toward the bushing ( 100 ) with the tail ( 300 ) cooperating with the receiver ( 400 ), and resulting in the nut ( 200 ) forcing the expansion device ( 500 ) from the initial undeformed state at the ED first position ( 530 ) abutting the transition ( 630 ) to the expanded state at the ED second position ( 532 ), thereby moving an ED translation distance ( 534 ), which elastically deforms the expansion device ( 500 ) and changes the ED initial max dimension ( 518 ) to the ED expanded max dimension ( 520 ), and the ED initial exterior surface gap angle ( 526 ) to the ED expanded exterior surface gap angle ( 528 ); and
wherein every 10 degree increase from the ED initial exterior surface gap angle ( 526 ) to the ED expanded exterior surface gap angle ( 528 ) results in at least a 1% increase of the ED initial max dimension ( 518 ) to the ED expanded max dimension ( 520 ).
2. The reusable blind fastener of claim 1 , wherein the ED expanded exterior surface gap angle ( 528 ) is at least 20% greater than the ED initial exterior surface gap angle ( 526 ).
3. The reusable blind fastener of claim 1 , wherein the ED initial exterior surface gap angle ( 526 ) is less than 75 degrees.
4. The reusable blind fastener of claim 1 , wherein every 10 degree increase from the ED initial exterior surface gap angle ( 526 ) to the ED expanded exterior surface gap angle ( 528 ) results in no more than a 4.5% increase of the ED initial max dimension ( 518 ) to the ED expanded max dimension ( 520 ).
5. The reusable blind fastener of claim 1 , wherein the transition angle ( 640 ) is no more than 12.0 degrees.
6. The reusable blind fastener of claim 1 , wherein the tail dextral wall ( 310 ) and the tail sinistral wall ( 312 ) converge toward one another at a tail taper ( 316 ), and imaginary lines extending from the tail dextral wall ( 310 ) and the tail sinistral wall ( 312 ) converge to a tail convergence point ( 313 ).
7. The reusable blind fastener of claim 6 , wherein when the nut ( 200 ) has forced the expansion device ( 500 ) to the expanded state at the ED second position ( 532 ), the tail convergence point ( 313 ) is located beyond the nut distal end ( 202 ).
8. The reusable blind fastener of claim 6 , wherein the receiver dextral wall ( 410 ) and the receiver sinistral wall ( 412 ) converge toward one another at a receiver taper ( 416 ).
9. The reusable blind fastener of claim 8 , wherein the receiver taper ( 416 ) is less than the tail taper ( 316 ), and the tail taper ( 316 ) is no more than 24 degrees.
10. The reusable blind fastener of claim 1 , wherein the tail width ( 314 ) is at least 25% of the bushing bore diameter ( 118 ) and no greater than 70% of the ED initial max dimension ( 518 ).
11. The reusable blind fastener of claim 1 , wherein the expansion device ( 500 ) includes at least two independent expansion devices adjacent to one another.
12. The reusable blind fastener of claim 1 , wherein the tail length ( 306 ) is at least 50% of the nut length ( 206 ), and the minimum tail width ( 314 ) is at least 25% of the tail length ( 306 ).
13. The reusable blind fastener of claim 1 , wherein the density of the expansion device ( 500 ) is no more than 6.8 g/cc, and the expansion device ( 500 ) has an elongation to break of at least 7%.
14. The reusable blind fastener of claim 13 , wherein the expansion device ( 500 ) is formed of NiTi or Ni—Ti—Cu alloy.
15. The reusable blind fastener of claim 1 , wherein at least one of the nut ( 200 ) and the screw ( 600 ) are formed of a metallic material with a density of less than 4.6 g/cc, and the bushing ( 100 ) is non-metallic and is no more than 2.0 grams.
16. A reusable blind fastener, comprising:
a bushing ( 100 ), a nut ( 200 ), a tail ( 300 ), a receiver ( 400 ), an expansion device ( 500 ), and a screw ( 600 );
the bushing ( 100 ) having a bushing distal end ( 102 ), a bushing proximal end ( 104 ), a bushing length ( 106 ) between the bushing distal end ( 102 ) and the bushing proximal end ( 104 ), and a bushing bore ( 110 ) extending through the bushing ( 100 ) from the bushing distal end ( 102 ) to the bushing proximal end ( 104 ), wherein the bushing bore ( 110 ) has a bushing bore longitudinal axis, and a bushing bore diameter ( 118 );
the nut ( 200 ) having a nut distal end ( 202 ), a nut proximal end ( 204 ), a nut length ( 206 ) from the nut distal end ( 202 ) to the nut proximal end ( 204 ), a nut bore ( 210 ) having a nut bore longitudinal axis;
the tail ( 300 ) extending from the bushing ( 100 ), and having a tail distal end ( 302 ), a tail proximal end ( 304 ), a tail length ( 306 ) between the tail distal end ( 302 ) and the tail proximal end ( 304 ), a tail dextral wall ( 310 ), a tail sinistral wall ( 312 ), and a tail width ( 314 ) measured along an exterior surface of the tail ( 300 ) in a direction perpendicular to the bushing bore longitudinal axis, wherein the tail length ( 306 ) is at least 50% of the nut length ( 206 ), a minimum tail width is at least 25% of the tail length ( 306 ), and the tail dextral wall ( 310 ) and the tail sinistral wall ( 312 ) converge toward one another at a tail taper ( 316 );
the receiver ( 400 ) is formed in the nut ( 200 ) and having a receiver distal end ( 402 ), a receiver proximal end ( 404 ), a receiver dextral wall ( 410 ), a receiver sinistral wall ( 412 ), and a receiver width ( 414 ) between the receiver dextral wall ( 410 ) and the receiver sinistral wall ( 412 ) in a direction perpendicular to the nut bore longitudinal axis;
the expansion device ( 500 ) having an ED exterior surface ( 510 ) that is discontinuous and having an initial sinistral gap opening point ( 527 A) and an initial dextral gap opening point ( 527 B), which define an ED initial exterior surface gap angle ( 526 ), wherein the expansion device ( 500 ) has an initial undeformed state with an ED initial max dimension ( 518 ) and the ED initial exterior surface gap angle ( 526 ), and an expanded state with an ED expanded max dimension ( 520 ) greater than the ED initial max dimension ( 518 ) whereby the initial sinistral gap opening point ( 527 A) and the initial dextral gap opening point ( 527 B) have spread apart to an expanded sinistral gap opening point ( 529 A) and an expanded dextral gap opening point ( 529 B), which define an ED expanded exterior surface gap angle ( 528 ) greater than the ED initial exterior surface gap angle ( 526 );
the screw ( 600 ) having a threaded portion ( 620 ), and a transition ( 630 ) adjacent the threaded portion ( 620 ), wherein the transition ( 630 ) has a transition angle ( 640 );
wherein the screw ( 600 ) extends through the bushing ( 100 ) via the bushing bore ( 110 ), the expansion device ( 500 ) is received over the screw ( 600 ), and the nut bore ( 210 ) engages the screw threaded portion ( 620 ), such that rotation of the screw ( 600 ) draws the nut ( 200 ) toward the bushing ( 100 ) with the tail ( 300 ) cooperating with the receiver ( 400 ), and resulting in the nut ( 200 ) forcing the expansion device ( 500 ) from the initial undeformed state at the ED first position ( 530 ) abutting the transition ( 630 ) to the expanded state at the ED second position ( 532 ), thereby moving an ED translation distance ( 534 ), which elastically deforms the expansion device ( 500 ) and changes the ED initial max dimension ( 518 ) to the ED expanded max dimension ( 520 ), and the ED initial exterior surface gap angle ( 526 ) to the ED expanded exterior surface gap angle ( 528 );
wherein at least one of the nut ( 200 ) and the screw ( 600 ) are formed of a metallic material with a density of less than 4.6 g/cc, and the bushing ( 100 ) is non-metallic and is no more than 2.0 grams; and
wherein every 10 degree increase from the ED initial exterior surface gap angle ( 526 ) to the ED expanded exterior surface gap angle ( 528 ) results in at least a 1% increase of the ED initial max dimension ( 518 ) to the ED expanded max dimension ( 520 ).
17. The reusable blind fastener of claim 16 , wherein the ED expanded exterior surface gap angle ( 528 ) is at least 20% greater than the ED initial exterior surface gap angle ( 526 ), and the ED initial exterior surface gap angle ( 526 ) is less than 75 degrees.
18. The reusable blind fastener of claim 16 , wherein every 10 degree increase from the ED initial exterior surface gap angle ( 526 ) to the ED expanded exterior surface gap angle ( 528 ) results in no more than a 4.5% increase of the ED initial max dimension ( 518 ) to the ED expanded max dimension ( 520 ).
19. The reusable blind fastener of claim 16 , wherein the transition angle ( 640 ) is no more than 12.0 degrees, the tail width ( 314 ) is at least 25% of the bushing bore diameter ( 118 ) and no greater than 70% of the ED initial max dimension ( 518 ), and imaginary lines extending from the tail dextral wall ( 310 ) and the tail sinistral wall ( 312 ) converge to a tail convergence point ( 313 ), and when the nut ( 200 ) has forced the expansion device ( 500 ) to the expanded state at the ED second position ( 532 ), the tail convergence point ( 313 ) is located beyond the nut distal end ( 202 ).
20. The reusable blind fastener of claim 16 , wherein the expansion device ( 500 ) includes at least two independent expansion devices adjacent to one another.