Blind fasteners

Patent metadata

Field	Value
Publication number	US-9422964-B2
Application number	US-201414276070-A
Country	US
Kind code	B2
Filing date	May 13, 2014
Priority date	Apr 10, 2009
Publication date	Aug 23, 2016
Grant date	Aug 23, 2016

Abstract

Fasteners for producing double blind joints where the fastener is not visible or accessible are provided. The fasteners comprise a shape memory polymer that may be used to fasten workpieces by heating the fasteners, inducing recovery of the original, permanent shape of the fasteners.

First claim

What is claimed is:

1. A fastener comprising a thermoplastic polyurethane shape memory polymer having a transition temperature (T trans ) of at least 50° C.; the fastener comprising a length, a width, and no head; wherein the fastener is axially oriented at least 50% in the longitudinal direction.

2. The fastener of claim 1 , wherein the thermoplastic polyurethane shape memory polymer comprises a thermoplastic polyurethane with a hard segment as a permanent shape and a soft segment as a switching temporary shape.

3. The fastener of claim 1 , wherein the thermoplastic polyurethane shape memory polymer is partly derived from methylene diphenyl diisocyanate.

4. The fastener of claim 1 , wherein the fastener is axially oriented at least 100% in the longitudinal direction.

5. The fastener of claim 4 , wherein the fastener is axially oriented 150% in the longitudinal direction.

6. The fastener of claim 4 , wherein the fastener is axially oriented at least 200% in the longitudinal direction.

7. The fastener of claim 1 , wherein the thermoplastic polyurethane shape memory polymer has a transition temperature (T trans ) of at least 100° C.

8. The fastener of claim 7 , wherein the thermoplastic polyurethane shape memory polymer has a transition temperature (T trans ) of at least 125° C.

9. The fastener of claim 1 , wherein the fastener has a rod shape.

10. The fastener of claim 9 , wherein the fastener is a rivet.

11. The fastener of claim 1 , wherein the fastener has a solid cross-section.

12. The fastener of claim 11 , wherein the fastener has a cross-section selected from the group consisting of cylindrical, ovoid, square, rectangular, and higher polygonal.

13. The fastener of claim 12 , wherein the fastener has a cylindrical cross-section.

14. The fastener of claim 13 , wherein an outer surface of the fastener comprises grooves or ridges.

15. The fastener of claim 1 , wherein the transition temperature (T trans ) is a glass transition temperature (T g ).

16. The fastener of claim 15 , wherein the thermoplastic polyurethane shape memory polymer has a glass transition temperature (T g ) of at least 100° C.

17. The fastener of claim 16 , wherein the thermoplastic polyurethane shape memory polymer has a glass transition temperature (T g ) of at least 125° C.

Assignees

• 3M Innovative Properties Co

Inventors

• Rule Joseph D
• Lewandowski Kevin M

Classifications

• B29C66/8322

  Joining or pressing tools reciprocating along one axis · CPC title

• B29C66/91943

  higher than said glass transition temperature · CPC title

• B29C65/604

  in both parts · CPC title

• B29C65/68

  using auxiliary shrinkable elements · CPC title

• F16B19/06 Primary

  Solid rivets made in one piece · CPC title