Textured sleeves for fasteners
View Patent ↗A fastener adapted to be installed in a hole of a composite structure includes a sleeve, a pin member, and a locking member. The sleeve has an outer surface having an outer diameter. The outer surface of the sleeve is textured. The outer diameter of the tubular portion is less than an inner diameter of the hole of the structure. The pin member has a shank portion. The sleeve is adapted to expand radially over the shank portion of the pin member to form an interference fit between the outer surface of the sleeve and the hole of the structure so as to provide an installed position of the fastener. When the fastener is in the installed position, the texture of the outer surface of the tubular portion deforms to engage with voids of the composite material present on the inner surface of the hole.
1. A fastener, comprising:
a sleeve having a tubular portion and an enlarged head at a first end of said tubular portion, said tubular portion having an inner surface having an inner diameter and an outer surface having an outer diameter, said outer diameter of said tubular portion being less than an inner diameter of a hole of a structure in which the fastener is adapted to be installed, said outer surface of said tubular portion being textured;
a pin member having a first end, a second end opposite said first end of said pin member, an enlarged pin head at said first end of said pin member, a locking portion at said second end, and a shank portion between said first and second ends of said pin member, said shank portion having a diameter greater than said inner diameter of said sleeve; and
a locking member adapted to fit over said locking portion of said pin member,
wherein said sleeve is adapted to expand radially over said shank portion of said pin member to form an interference fit between said outer surface of said sleeve and the hole of the structure so as to provide an installed position of said fastener,
wherein when said fastener is in said installed position, said texture of said outer surface of said tubular portion of said sleeve engages with voids present within the inner surface of the hole, and
wherein said textured outer surface of said tubular portion of said sleeve has a surface roughness that is greater than or equal to about 1.4microns.
2. The fastener of claim 1 , wherein said structure comprises a composite maters, and wherein said engagement of said texture of said outer surface of said tubular portion with the voids of the composite material displaces sealant from the voids of the composite material.
3. The fastener of claim 1 , wherein said textured outer surface of said tubular portion of said sleeve has a surface roughness that is about 1.4 micron.
4. The fastener of claim 1 , wherein said sleeve has a core hardness in a range from about 30 to about 35 on a Rockwell C hardness scale.
5. The fastener of claim 1 , wherein said sleeve has an electrical conductivity that is greater than about 20% of an International Annealed Copper Standard.
6. The fastener of claim 1 , wherein said sleeve has an anodic index less than about 0.65 V.
7. The fastener of claim 1 , wherein said inner surface of said tubular portion comprises a low-friction coating, and wherein, when said fastener is in said installed position, a first coefficient of friction exists between said inner surface of said tubular portion of said sleeve and said shank portion of said pin member, a second coefficient of friction exists between said outer surface of said tubular portion of said sleeve and the inner surface of the hole of the structure, and said first coefficient of friction remains less than said second coefficient of friction when said shank portion of said pin member is moved within said sleeve.
8. The fastener of claim 1 , wherein said locking member is a collar.
9. The fastener of claim 8 , wherein said locking member includes a counterbore portion that is adapted to fit over said locking portion of said pin member and compress said sleeve around said pin member.