Landing gear mechanism for aircraft
Landing gear mechanism for aircraft are provided which include first and second connecting arms and front and rear wheels operatively associated with the first and second connecting arms, respectively. A balance beam element is indirectly linked to the front and rear wheels through each one of the connecting arms and shock absorber elements, respectively, so that the front portion of the balance beam element is associated with the first portion of the first shock absorber element. A positioning damper element is hingedly connected to the aircraft structure and also connected, directly or indirectly, to a portion of the body of the balance beam element.
1. A retractable landing gear mechanism for extended and retracted positions relative to an aircraft structure, wherein the landing gear mechanism comprises:
at least front and rear wheels,
at least front and rear connecting arms having one end operatively connected to the front and rear wheels, respectively, and an opposite end pivotally connected to aircraft structure;
a balance beam element having front and rear end portions;
front and rear shock absorbers having lower and upper ends, wherein the lower ends of the front and rear shock absorbers are pivotally connected to the one end of the front and rear connecting arms, respectively, and wherein the upper ends of the front and rear shock absorbers are connected pivotally to the front and rear end portions of the balance beam element at respective front and rear pivot points, wherein the balance beam is thereby indirectly linked to the front and rear wheels through each one of the front and rear connecting arms and each of the front and rear shock absorber elements, respectively; and
a retracting arm having an upper end pivotally connected to the aircraft structure and a lower end pivotally connected to the balance beam element at an intermediate pivot point which is aligned with and equidistantly positioned between the front and rear pivot points.
2. The retractable landing gear mechanism according to claim 1 , further comprising a gear up lock box, and wherein the front end portion of the balance beam element includes a coupling extension which couples with the gear up lock box when the landing gear mechanism is in a retracted position.
3. The retractable landing gear mechanism according to claim 1 , further comprising a positioning damper element hingedly connected to the aircraft structure at an upper end thereof and to a portion of the balance beam element.
4. The retractable landing gear mechanism according to claim 1 , further comprising a locking arm connected to the balance beam element, and a maneuvering actuator device connected to the locking arm.
5. The retractable landing gear mechanism according to claim 4 , wherein one end of the maneuvering actuator device is hingedly connected to the aircraft structure.
6. The retractable landing gear mechanism according to claim 5 , wherein the locking arm comprises upper and lower hinged semi-arms, and wherein an opposite end of the maneuvering actuator is pivotally connected to the upper semi-arm.
7. The retractable landing gear mechanism according to claim 6 , further comprising a positioning damper element hingedly connected to the aircraft structure at one end thereof and to the balance beam element at an opposite end thereof.
8. The retractable landing gear mechanism according to claim 6 , wherein a lower semi-arm of the locking arm and a lower end of the retracting arm are respectively internally and externally hinged to balance beam element.
9. The retractable landing gear mechanism according to claim 4 , further comprising a locking arm comprised of at least upper and lower semi-arms joined to one another at a hinged connection to allow hinged movement of the locking arm in response to operation of the maneuvering actuator device, wherein the lower semi-arm is hingedly connected to the balance beam element at the intermediate pivot point and the upper semi-arm is hingedly connected to the aircraft structure.
10. The retractable landing gear mechanism according to claim 9 , wherein the maneuvering actuator includes a moving rod which is pivotally connected to a central part of the upper semi-arm of the locking arm.
11. The retractable landing gear mechanism according to claim 9 , wherein the locking arm comprises a locking spring for maintaining the locking arm in a locked position.
12. The retractable landing gear mechanism according to claim 1 , further comprising a maneuvering actuator, front and rear bellcranks, and a connecting bar interconnecting the front and rear bellcranks and arranged below and parallel to the balance beam element, wherein the maneuvering actuator has a first hinged end which is connected to an upper part of the balance beam element, and a second hinged end connected to a top of a rear bellcrank.
13. The retractable landing gear mechanism according to claim 12 , wherein the rear and front bellcranks are hingedly interconnected to the balance beam element and the rear and front shock absorbers, respectively.
14. The retractable landing gear mechanism according to claim 1 , further comprising a locking arm which includes a plurality of hingedly interconnected semi-arms each having first and second opposite ends, wherein when the landing gear is in the extended position, the semi-arms are disposed so that a first end of a first semi-arm is angularly connected to a first end of a second semi-arm, a second end of the second semi-arm is angularly connected to a first end of a third semi-arm, a second end of the third semi-arm is connected so as to be in a straight and locked manner to a first end of a fourth semi-arm, and a second end of the fourth semi-arm is angularly connected to a second end of the first semi-arm.
15. The retractable landing gear mechanism according to claim 14 , a spring to assist in the locking between the second end of the third semi-arm and the first end of the fourth semi-arms.
16. The retractable landing gear mechanism according to claim 14 , wherein the second ends of the first and fourth semi-arms and a first end of a fifth semi-arm are hingedly connected to one another at a common hinge connection point P 1 , and wherein a second end of the fifth semi-arm is hingedly connected to the aircraft structure at a hinge connection point P 2 .
17. The retractable landing gear mechanism according to claim 16 , wherein the second end of the second semi-arm and the first end of the third semi-arm are hinged to one another and to the aircraft structure at a common hinge connection point P 3 .
18. The retractable landing gear mechanism according to claim 16 , further comprising a maneuvering actuator and a positioning damper element, wherein the maneuvering actuator has a first end thereof hingedly connected to the fifth semi-arm and a second end thereof hingedly connected to the aircraft structure, and wherein the positioning damper element has a second end thereof hingedly connected to the aircraft structure and a first end thereof hingedly connected to a sixth semi-arm which is connected to the balance beam element.
19. The retractable landing gear mechanism according to claim 16 , wherein when the retractable landing gear mechanism is in the extended position thereof, a bisecting line beginning at a vertex formed by the first and second semi-arms is oriented parallel to the front and rear shock absorber elements, and wherein the fifth semi-arm is oriented relative to an imaginary line passing through the hinge point P 1 and parallel to a longitudinal axis of the balance beam element at an angle between 270° and 360°.
20. The retractable landing gear mechanism according to claim 14 , wherein the first end of the first semi-arm and the first end of the second semi-arm are hingedly connected to one another and to a center portion of the balance beam element at a common hinge connection point P 4 .
21. The retractable landing gear mechanism according to claim 1 , wherein the upper and lower ends of the retracting arm are pivotally connected to the balance beam element and the aircraft structure at hinge points P 4 and P 5 , respectively, and wherein the retractable landing gear mechanism further comprises a maneuvering actuator having a second end thereof hingedly connected to the aircraft structure at a hinge point P 6 , and a first end thereof hingedly connected to the retracting arm at a hinge point P 7 located between the hinge points P 4 and P 5 .
22. The retractable landing gear mechanism according to claim 21 , further comprising a pin which is capable of being hydraulically driven in a direction perpendicular to the balance beam element.
23. The retractable landing gear mechanism according to claim 1 , wherein the upper and lower ends of the retracting arm are pivotally connected to the balance beam element and the aircraft structure at hinge points P 4 and P 8 , respectively, and wherein the retractable landing gear mechanism further comprises a maneuvering actuator which comprises an internal locking device, the maneuvering actuator having a second end thereof which is hingedly connected to the aircraft structure at a hinge point P 9 and a first end is hingedly connected to the balance beam element at the hinge point P 4 .
24. The retractable landing gear mechanism according to claim 23 , which further comprises a positioning damper element having a second end hingedly connected to the aircraft structure and a first end hingedly connected to an arm of the balance beam element.
25. The retractable landing gear mechanism according to claim 1 , further comprising a locking element which includes a plurality of hingedly interconnected semi-arms each having first and second ends, and wherein the second ends of first and fourth semi-arms and a first end of a fifth semi-arm are hingedly connected to one another at a common hinge connection point P 10 , and wherein when the landing gear is in the extended position, the first semi-arm is parallel to the front and rear shock absorbers.
26. The retractable landing gear mechanism according to claim 25 , wherein the first end of the fifth semi-arm is hingedly connected to the aircraft structure at the hinge connection point P 11 , and wherein the second end of the second semi-arm and the first end of the third semi-arm are hinged to the aircraft structure at a common hinge point P 3 .
27. The retractable landing gear mechanism according to claim 26 , further comprising a maneuvering actuator having a first end thereof hingedly connected to the fifth semi-arm and a second end thereof hingedly connected to the aircraft structure.