Temporally staged rapid panel access fastener for highly curved panels

摘要

A fastener for highly curved access panels on aircraft or other structures, featuring a bottom-grasping design allowing for an unblemished outer panel surface, simple and rapid pneumatic fastener actuation, built-in clamping pre-load, and full retractability of the fastener inside the supporting structure. The fastener includes a Belleville spring with a piston centrally disposed therein, where the piston and spring deflect outward upon application of pneumatic pressure. A pressure chamber within the piston has inlet and outlet orifices designed so that the pressure in the piston chamber gradually increases, requiring several seconds to reach a pressure which causes locking dogs in the piston to deploy radially into a cavity in the access panel. When pressure is removed, the Belleville spring relaxes, the locking dogs grasp a lip of the cavity, and the access panel is latched onto the structure with a clamping pre-load. A pneumatic sequence for unlatching is also provided.

主权项

1. An access panel fastener system, said system comprising:
a pneumatic chamber incorporated in a fixed structure; a Belleville spring retained around its outer periphery to the fixed structure, where a lower surface of said spring is in fluid communication with the pneumatic chamber and the spring is responsive to a pneumatic pressure in the chamber; a pneumatic piston slidably disposed through a central hole in the Belleville spring, a lower end of said piston being in fluid communication with the pneumatic chamber and responsive to the pneumatic pressure, where the piston deploys upward until a piston base flange contacts the lower surface of the Belleville spring when the pneumatic pressure in the pneumatic chamber exceeds a first pressure threshold, and where the Belleville spring deflects upward when the pneumatic pressure in the pneumatic chamber exceeds a second pressure threshold; a piston chamber located in a central bore of the piston with a lower orifice proximate the lower end of the piston and an upper orifice proximate an upper end of the piston, where pressurized air from the pneumatic chamber flows through the lower orifice into the piston chamber and flows out of the piston chamber through the upper orifice; a plurality of locking dogs slidably disposed in the upper end of the piston, where the locking dogs deploy radially outward when the pneumatic pressure in the piston chamber exceeds a third pressure threshold; and a retainer cavity mounted on a lower surface of a removable panel such that an opening of the cavity faces downward toward the fixed structure, and where the locking dogs when deployed engage with the retainer cavity to lock the removable panel to the fixed structure, where the fastener system latches the removable panel to the fixed structure upon application of a latching sequence of pneumatic pressures, and the fastener system unlatches the removable panel from the fixed structure upon application of an unlatching sequence of pneumatic pressures.