Folding wing-tip system

A method of monitoring a latched and locked condition of a plurality of latch pins each having a latch position in which it latches a folding aircraft wing tip in a spread position, comprising:

• providing each said latch pin with a primary lock and a secondary lock, each said lock having a locked position in which it blocks movement of said latch pin out of said latch position;
• configuring and positioning said primary locks and said secondary locks so that each said primary lock mechanically blocks its corresponding secondary lock from moving into said secondary lock's locked position when said primary lock is out of its locked position;
• ganging said secondary locks together so that they all move together into and out from their locked positions;
• sensing movement of said secondary locks into their locked positions and sending a signal in response to said movement of said secondary locks;
• and
• using said signal to determine that all of said latch pins are latched and all of said primary and secondary locks are in their locked positions.

A method for determining if a folding aircraft wing tip is fully spread and of sequencing spreading of the wing tip and latching it into a spread position, comprising:

• with the wing tip in a folded position, positioning an inhibitor in an inhibit position in which it blocks movement of a latch pin into a latch position and in which it will be contacted and moved by the wing tip as the wing tip moves toward said spread position;
• linking said inhibitor to a valve member of a valve to translate movement of said inhibitor caused by contact with the wing tip into movement of said valve member from a first position in which a sense port is connected to a first hydraulic pressure to a second position in which said sense port is connected to a second hydraulic pressure;
• connecting said sense port to an additional valve and transmitting said second hydraulic pressure from said sense port to said additional valve;
• and
• allowing said second hydraulic pressure to shift said additional valve to, in turn, cause hydraulic pressure to be supplied to extend said latch pin.

A method of preventing in-flight movement of a wing tip, in a folding wing-tip aircraft, from a spread position to a folded position, comprising:

• latching the wing tip into said spread position by moving a plurality of hydraulically actuated latch pins into a latch position;
• providing each said latch pin with a primary lock and a secondary lock, each said lock being hydraulically actuated and having a locked position in which it blocks movement of said latch pin out of said latch position;
• biasing said secondary locks into their locked positions;
• configuring and positioning said primary locks and said secondary locks so that each said secondary lock mechanically blocks its corresponding primary lock from moving out from said primary lock's locked position when said secondary lock is in its locked position;
• and
• during flight, isolating said latch pins and said primary and secondary locks from hydraulic pressure.

A method of locking a folding aircraft wing tip of a folding wing system into a folded position, comprising:

• providing a hydraulic fold actuator having lock mechanism, and providing an isolation valve;
• hydraulically operating said actuator to move it into a fold position and thereby move said wing tip into said folded position;
• automatically activating said lock mechanism to lock said actuator in said fold position in response to movement of said actuator into said fold position;
• generating an electrical signal in response to locking said actuator;
• and
• using said signal to cause said valve to depressurize the system, to isolate said actuator, including said lock mechanism, from hydraulic power, and allowing said actuator to act as a strut to hold said wing tip in said folded position.