Mechanism for moving and maintaining position of an aircraft wing slat
A mechanism for moving an aircraft wing slat between a retracted position and a deployed position includes a rib, an arm, a first bar and a second bar. The arm is disposed generally parallel with the rib and is configured for attachment with the wing slat. The rib, the arm and the first and second bars cooperate to form a four-bar linkage which is rotatable about connection points in a negative pitch rotational direction to dispose the arm in the deployed position, and in a positive pitch rotational direction to disposing the arm in the retracted position. The mechanism includes additional structures for maintaining the arm in the deployed position, including a magnetic extend stop and a standoff, an arm lobe and a cross-bolt, and a bar lobe and a linear member.
1. A mechanism for moving a slat of an aircraft wing of an aircraft, wherein the aircraft defines forward, aftward, upward, downward and lateral directions, comprising:
a first rib having a first rib face on a first rib side, a forward first rib connection point on the first rib side and an aftward first rib connection point on the first rib side;
a generally elongate arm disposed generally parallel with the first rib on the first rib side, the arm having a first arm face on a first arm side facing the first rib face, a forward arm connection point at a forward arm end, a first aftward arm connection point on the first arm side at an aftward arm end, and a first middle arm connection point on the first arm side at a middle arm portion between the forward and aftward arm ends;
a first bar having a first bar upper end rotatably attached to the arm at the first middle arm connection point and a first bar lower end rotatably attached to the first rib at the forward first rib connection point;
a second bar having a second bar upper end rotatably attached to the arm at the first aftward arm connection point and a second bar lower end rotatably attached to the first rib at the aftward first rib connection point;
a first extend stop disposed on the first rib face; and
a first standoff disposed on the first arm face;
wherein the first rib, the arm and the first and second bars cooperate to form a first four-bar linkage, wherein the first and second bars are rotatable about their respective forward and aftward first rib connection points in a negative pitch rotational direction until the first standoff contacts the first extend stop, thereby disposing the arm in a deployed position, and in a positive pitch rotational direction until the first standoff is moved away from the first extend stop by a first predetermined amount, thereby disposing the arm in a retracted position; and
wherein one of the first extend stop and the first standoff is magnetic, and the other of the first extend stop and the first standoff is magnetic or ferromagnetic.
2. The mechanism of claim 1 , wherein magnetic attraction between the first extend stop and the first standoff in the deployed position urges the arm to remain in the deployed position.
3. The mechanism of claim 1 , further comprising:
an aircraft wing slat attached to the forward arm connection point.
4. The mechanism of claim 1 , wherein the first extend stop is magnetic and has a first polarity, and wherein the first standoff is magnetic and has a second polarity that is opposite the first polarity.
5. The mechanism of claim 1 , wherein one of the first extend stop and the first standoff is magnetic, and wherein the other of the first extend stop and the first standoff is ferromagnetic.
6. The mechanism of claim 1 , wherein at least one of the first middle arm connection point and the first aftward arm connection point is a circular boss protruding outward from the first arm face, and at least one of the first bar upper end and the second bar upper end is a circular dog bone end.
7. The mechanism of claim 1 , wherein at least one of the forward first rib connection point and the aftward first rib connection point is a circular boss protruding outward from the first rib face, and at least one of the first bar lower end and the second bar lower end is a circular dog bone end.
8. The mechanism of claim 1 , wherein at least one of the first middle arm connection point and the first aftward arm connection point is a circular through-hole extending through the arm and having a respective cross-member disposed therethrough.
9. The mechanism of claim 1 , wherein at least one of the forward first rib connection point and the aftward first rib connection point is a circular through-hole extending through the first rib and having a respective cross-member disposed therethrough.
10. The mechanism of claim 1 , wherein the arm has a second arm face on a second arm side opposite the first arm side, a second aftward arm connection point on the second arm side at the aftward arm end, and a second middle arm connection point on the second arm side at the middle arm portion, the mechanism further comprising:
a second rib having a second rib face on a second rib side, a forward second rib connection point on the second rib side and an aftward second rib connection point on the second rib side, wherein the second rib face faces toward the first rib face and the arm is disposed between the first and second ribs;
a third bar having a third bar upper end rotatably attached to the arm at the second middle arm connection point and a third bar lower end rotatably attached to the second rib at the forward second rib connection point; and
a fourth bar having a fourth bar upper end rotatably attached to the arm at the second aftward arm connection point and a fourth bar lower end rotatably attached to the second rib at the aftward second rib connection point;
wherein the second rib, the arm and the third and fourth bars cooperate to form a second four-bar linkage, wherein the third and fourth bars are rotatable about their respective forward and aftward second rib connection points in the negative and positive pitch rotational directions in concert with the first four-bar linkage.