Expanded fastener for a honeycomb structure and method of assembly

Abstract

An expanding panel fastener assembly for affixing a honeycomb panel structure to a support structure is disclosing having an insert member that attaches to a hole drilled within the honeycomb panel. A flexible sleeve and retainer assembly includes a molded flexible sleeve, an expander member and a retainer member. A sleeve spacer can further be attached to the flexible sleeve to assist in retaining it within the insert member. By providing a fastener for engagement with the retainer member, the expander member can further prevent withdrawal of the retainer member and can further assist in expanding the flexible sleeve to provide a sealing configuration with any support structure.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority from Provisional Application Ser. No. 60 / 439,512 filed on Jan. 13, 2003, the contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention is directed to a panel fastener assembly including an elastomeric sleeve and retainer assembly that can be inserted through a hole in a panel for receiving fasteners to secure the fastener to the panel and a support substrate. [0004] 2. Description of Related Art [0005] In the field of aircraft and aerospace craft assembly, lightweight panels such as honeycomb panel structures are utilized and are mounted to bulkheads and aluminum intercostal ribs or beams that extend within the exterior housing of the aircraft structure. [0006] Various prior art methods of attaching honeycomb panels as floors or walls in aircraft manufacturing frequently requires the use of a female threaded clip nut wh...

AI Technical Summary

Benefits of technology

[0011] An expanding panel fastener assembly for affixing a honeycomb panel structure to a support structure includes an insert member of a configuration for attaching through a hole that is bored or drilled through a honeycomb panel. Insert members of numerous different configurations can be utilized and as such, forms only one possible component in one form of the present invention. A flexible sleeve and retainer assembly has a configuration to extend through the installed insert member and the corresponding support structure whereby a portion of the assembly will be retained by the insert member. The flexible sleeve and retainer assembly includes a moldable flexible sleeve, an expander member and a retainer member. A fastener member of a configuration that extends through the flexible sleeve when installed in the panel and further through the support structure and thereby operatively engages the retainer member such as a nut member is utilized to complete the assembly. Tightening of the fastener member such as a screw relative to the nut member will expand the expander member below the support structure to thereby prevent withdrawal of the nut member. Additionally, this flexible sleeve is also compressed and expanded so that it can further provide a sealing configuration with the support structure. Since the flexible sleeve is relatively movable, misaligmnent problems can be addressed within certain tolerances, and issues of vibration and corrosion can be significantly reduced.

[0013] Finally, fastener members such as screws can be inserted through the panel within the flexible sleeve that also extends through the support structure opening. The fastener member can then engage the retainer member such as a nut, and as the nut is tightened, the fastener member will expand an expander member, thereby preventing the nut member from being pulled through the opening in the support structure.

[0014] The operative engagement of the fastener member with the retainer member such as a nut can further compress the flexible sleeve which can be formed from rubber or a silicone material to thereby further seal against the support structure and help reduce any vibration and corrosion issues.

Problems solved by technology

Problems, however, have occurred in the additional labor that is required in the insertion and alignment of the clip nuts with the corresponding holes in the support structure.

As a practical matter, when a honeycomb panel is installed, some attachment points frequently are found not to have the clip nuts properly installed and, for example, if the honeycomb structure is a floor board, it may have to be removed, new clip nuts installed, and then the floor board reinstated.

The same problem can occur if the clip nut becomes stripped upon the insertion of the fastener.

Another problem that can occur with the clip nut installation on aircraft structure is possible galvanic corrosion that can be caused by the clip nut scratching and interacting between the aircraft structure and inserts in the floor boards and walls.

Since there is an iron-aluminum interface, corrosion can occur.

This problem further causes the walls and floor to resonate and can create unnecessary noise and vibration.

Additionally, misalignment problems are more prone to occur with use of the individual clip nuts.

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