Advanced lock design for ball-lock devices

Patent metadata

Field	Value
Publication number	US-9845143-B2
Application number	US-201514804171-A
Country	US
Kind code	B2
Filing date	Jul 20, 2015
Priority date	Jul 20, 2015
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A ball-lock type fastening device for connecting a work piece to a structure is disclosed. The fastening device includes a number of features designed to improve the reliability, repeatability and strength of the locking mechanism compared to traditional ball-lock fasteners. The features include the shape of the locking balls, the shape of the retention housing which engages the locking balls, and mechanisms for controlling deployment and retraction of the locking balls.

First claim

What is claimed is:

1. A fastener system comprising:
a cylindrical piston slidably mounted to a first structure, where the piston is fully retractable into the first structure and deployable outward a fixed distance from the first structure, and the piston includes an axial bore opening to a plurality of radial cross-bores proximal a top end of the piston;
a plurality of locking pills having inner and outer ends, one of said locking pills slidably disposed in each of the cross-bores of the piston, where the locking pills are configured to travel from a first position in which the pills are situated radially inward and entirely within the piston, to a second position where the pills are deployed radially outward where the outer ends extend beyond an outer surface of the piston, and where the locking pills have an undercut lip around a circumference of the outer end; and
a retainer cavity mounted on a lower surface of a second structure such that an opening of the cavity faces toward the first structure to receive the piston, where the retainer cavity includes an undercut surface on an inner lip, and where the retainer cavity has an undercut locking ridge around an inner circumference, and the locking ridge has a profile shape which corresponds to a profile shape of the undercut lip of the locking pills,
where the fastener system latches the second structure to the first structure via a latching sequence including placing the second structure adjacent the first structure, deploying the piston outward from the first structure into the retainer cavity in the second structure, deploying the locking pills radially outward to the second position by selectively supplying a pneumatic pressure via the axial bore in the piston, providing a bias force urging the piston back inward to the first structure after the locking pills have been deployed to the second position, and mechanically restraining the locking pills in the second position via engagement of the undercut lips of the locking pills with the locking ridge of the retainer cavity such that the locking pills cannot retract to the first position and the locking pills contact the undercut surface of the retainer cavity to latch the second structure to the first structure.

2. The fastener system of claim 1 wherein the latching sequence includes increasing the pneumatic pressure in a chamber in the first structure to exceed a first threshold in order to deploy the piston upward until a bottom end of the piston contacts a Belleville spring, increasing the pneumatic pressure to exceed a second threshold in order to deflect the Belleville spring upward, increasing the pneumatic pressure to exceed a third threshold in order to open a pneumatic valve in the axial bore of the piston and deploy the locking pills radially outward, decreasing the pressure below a fourth threshold in order to relax the Belleville spring and cause the locking pills to grasp the ridge of the retainer cavity, further decreasing the pressure below a fifth threshold in order to cause the pneumatic valve to close, and further decreasing the pressure to zero to complete the latching.

3. The fastener system of claim 2 wherein, following the latching sequence, the Belleville spring remains partially flexed and provides a tensile force on the piston such that the locking pills pull the second structure against the first structure with a clamping pre-load.

4. The fastener system of claim 1 wherein the plurality of locking pills is two locking pills each including a magnet on its inner end, where the magnets are oriented with opposite polarities facing radially inward so as to provide an attractive force, and the attractive force causes the locking pills to retract to the first position when the locking pills are not forced outward by the pneumatic pressure and the locking pills are not mechanically restrained in the second position.

5. The fastener system of claim 1 wherein:
the piston includes a plurality of pins fitted in the top end of the piston such that one of the pins protrudes into each of the cross-bores in the piston; and
the locking pills include a slot in a top surface thereof, where the pin extends into the slot, and deployment travel of the locking pills to the second position is limited by a first end of the slot contacting the pin, and retraction travel of the locking pills to the first position is limited by a second end of the slot contacting the pin.

6. The fastener system of claim 1 wherein the first structure is an aircraft and the second structure is an access panel, where the access panel must be attached to the aircraft when the aircraft is operational, and the access panel is removable from the aircraft for inspection or service.

7. The fastener system of claim 6 wherein at least three of the fastener systems are used to attach the access panel to the aircraft, and the access panel has a curvature which necessitates complete retraction of the piston into the aircraft prior to placing the access panel adjacent to the aircraft.

8. A fastener system comprising:
a cylindrical piston slidably mounted to a first structure, where the piston is fully retractable into the first structure and deployable outward a fixed distance from the first structure, and the piston includes an axial bore opening to and providing pneumatic pressure to a plurality of radial cross-bores proximal a top end of the piston, where the piston includes a plurality of pins fitted in the top end of the piston such that one of the pins protrudes into each of the cross-bores in the piston;
a plurality of locking pills having inner and outer ends, one of said locking pills slidably disposed in each of the cross-bores of the piston, where the locking pills are caused by the pneumatic pressure to travel from a first position in which the pills are situated radially inward and entirely within the piston, to a second position where the pills are deployed radially outward where the outer ends extend beyond an outer surface of the piston, wherein the locking pills include a slot in a top surface thereof, where the pin extends into the slot, and deployment travel of the locking pills to the second position is limited by a first end of the slot contacting the pin, and retraction travel of the locking pills to the first position is limited by a second end of the slot contacting the pin; and
a retainer cavity mounted on a lower surface of a second structure such that an opening of the cavity faces toward the first structure to receive the piston, where the retainer cavity includes an undercut surface on an inner lip,
where the fastener system latches the second structure to the first structure via a latching sequence including placing the second structure adjacent the first structure, increasing the pneumatic pressure in a chamber in the first structure to exceed a first threshold in order to deploy the piston upward until a bottom end of the piston contacts a Belleville spring, increasing the pneumatic pressure to exceed a second threshold in order to deflect the Belleville spring upward, increasing the pneumatic pressure to exceed a third threshold in order to open a pneumatic valve in the axial bore of the piston and deploy the locking pills radially outward, decreasing the pressure below a fourth threshold in order to relax the Belleville spring and cause the locking pills to grasp the ridge of the retainer cavity, further decreasing the pressure below a fifth threshold in order to cause the pneumatic valve to close, and further decreasing the pressure to zero to complete the latching.

9. The fastener system of claim 8 wherein:
the locking pills have an undercut lip around a circumference of the outer end;
the retainer cavity has an undercut locking rid

Assignees

• Northrop Grumman Systems Corp

Inventors

• Neal Matthew A
• Berg Stephen R
• Ehrlich Michael J
• Smith Charles R

Classifications

• F16B21/165

  with balls or rollers (for connections of rods or tubes engaged telescopically F16B7/1409) · CPC title

• F16B1/0057

  Mechanical Engineering · mapped topic

• F16B2021/14

  Mechanical Engineering · mapped topic

• F16B2001/0035

  Mechanical Engineering · mapped topic

• F16B19/109

  Temporary rivets, e.g. with a spring-loaded pin (special clamping devices for workpieces to be riveted together, e.g. operating through the rivet holes B21J15/42; hand tools for temporarily connecting sheets before or during assembly operations B25B31/005) · CPC title