Mark IV™ Structural Panel Fastener

The Mark IV panel fastener is a structural panel fastening system for aerospace composite structures. This panel fastening system incorporates the FlatBeam locknut design for superior vibration resistance. This feature also extends the locking capability to up to 1,500 seated cycles. All stud bolt configurations are held in the panel by a retaining ring.

Design features

The Mark IV panel fastener comprises a two-piece design. A flat beam lock nut provides excellent resistance to vibration-induced loosening and has a high cycle life of up to 250 seated cycles. In addition, a stud bolt features dual-lead threads for quick operation.

There are three basic variations within the Mark IV panel fastener system – plug type, hold-out type and twist-on type. Each is available with a radial-slot, hex or TORX® recess.

Cost-effective features

Reduction in down time:
Multiple lead thread configurations are available to facilitate quick operation for reduced down time.

Low maintenance:
When disengaged from the receptacle, the hold-out type of stud bolt can be pulled out to the hold-out position to facilitate easy removal of curved or hinged panels. Similarly, the receptacle nut portion can be replaced without removing rivets.

Forgiving grip range:
The stud bolt accommodates large variations in grip (up to 0.140 in.).

Easy installation:
The receptacles allow for radial float making it easier to assemble curved panels or panels with hole misalignment. The Mark IV panel fastener’s receptacle provides 0.020 in. minimum radial float, and versions allow for angular engagement of nut-plate to ease installation of curved panels.

TORX is a registered trademark of Acument Intellectual Properties, LLC.