Temporally staged rapid panel access fastener for highly curved panels
First Claim
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.
1 Assignment
0 Petitions
Accused Products
Abstract
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.
28 Citations
20 Claims
-
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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. An aircraft access panel fastener system, said system comprising:
-
a removable access panel located on an exterior surface of an aircraft; a pneumatic supply line which provides a pneumatic pressure, said pneumatic supply line being incorporated in a fixed structure of the aircraft; and a plurality of pneumatically-actuated fasteners for latching the access panel to the fixed structure, each of the fasteners comprising; a pneumatic chamber incorporated in the fixed structure, where the pneumatic chamber is in fluid communication with the pneumatic supply line; 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 the pneumatic pressure in the pneumatic 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 the access panel such that an opening of the cavity faces downward toward the fixed structure, where the locking dogs when deployed engage with the retainer cavity to lock the access panel to the fixed structure, and where the locking dogs have a shape which fits over a lower lip of the retainer cavity when in a latched condition such that the locking dogs cannot retract into the piston, where the plurality of fasteners latches the access panel to the fixed structure upon application of a latching sequence of pneumatic pressures, and the plurality of fasteners unlatches the access panel from the fixed structure upon application of an unlatching sequence of pneumatic pressures. - View Dependent Claims (12, 13, 14, 15)
-
-
16. A method for latching a removable access panel to a fixed structure, said method comprising:
-
providing a plurality of fasteners, where each of said fasteners includes a pneumatic chamber incorporated in the 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, a pneumatic piston slidably disposed through a central hole in the Belleville spring where a lower end of said piston is in fluid communication with the pneumatic chamber, 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, and a retainer cavity mounted on a lower surface of the access panel such that an opening of the cavity faces downward toward the fixed structure; placing the access panel in position on the fixed structure; increasing a pneumatic pressure in a pneumatic supply line from zero to a first pressure, said supply line being in fluid communication with the pneumatic chamber of each of the plurality of fasteners, where the first pressure causes the pneumatic piston in each of the fasteners to deploy upward into the retainer cavity until a piston base flange contacts the lower surface of the Belleville spring; increasing the pneumatic pressure in the supply line to a second pressure causing the Belleville spring in each of the fasteners to deflect upward; maintaining the pneumatic pressure in the supply line above the second threshold while a pressure in the piston chambers rises to exceed a third threshold in order to deploy the locking dogs radially outward; decreasing the pressure in the supply line below the second threshold in order to relax the Belleville springs and cause the locking dogs to grasp a lip of the retainer cavities; and further decreasing the pneumatic pressure in the supply line to zero. - View Dependent Claims (17, 18, 19, 20)
-
Specification