초록 ▼

A semi-levered landing gear includes a main strut, a wheel truck pivotally attached at a main pivot to a lower end of the main strut and supporting forward and aft wheels, and an auxiliary strut attached at its upper end to the main strut and at its lower end to the wheel truck forward of the main p

A semi-levered landing gear includes a main strut, a wheel truck pivotally attached at a main pivot to a lower end of the main strut and supporting forward and aft wheels, and an auxiliary strut attached at its upper end to the main strut and at its lower end to the wheel truck forward of the main pivot. The auxiliary strut includes a main piston that slides within a cylinder barrel and is attached at its lower end to the auxiliary pivot, and a floating piston that slides relative to the cylinder barrel and the main piston and divides the cylinder barrel into a pair of fluid chambers. The main piston includes snubbing holes or orifices through which fluid can flow between the two fluid chambers. The auxiliary strut also includes a lock-up valve that slides relative to the floating and main pistons and is configured to close the fluid path through the snubbing holes or orifices when the main and floating pistons are in predetermined positions relative to the lock-up valve, thereby locking the strut at a predetermined fixed length. The lock-up valve is configured such that the strut locks up at an intermediate length between a minimum and a maximum length of the strut, so that on takeoff, as the main strut extends, the auxiliary strut locks up to cause the wheel truck to tilt into a nose-up attitude. In one embodiment, the lock-up valve is actuatable to move into either a retracted position providing a short extension before locking up, or an extended position enabling the auxiliary strut to extend a greater amount before locking up. The auxiliary strut is also actuatable to extend the main piston for stowing the landing gear and to retract the main piston for tilting the wheel truck on landing approach.

대표청구항 ▼

1. A strut having lost motion and lock-up capabilities, comprising:a cylinder barrel having a closed end and an open end; a piston assembly slidably received through the open end of the cylinder barrel and comprising a floating piston contained within the cylinder barrel and slidable therein along a

1. A strut having lost motion and lock-up capabilities, comprising:a cylinder barrel having a closed end and an open end; a piston assembly slidably received through the open end of the cylinder barrel and comprising a floating piston contained within the cylinder barrel and slidable therein along an axis of the cylinder barrel, the floating piston having an end wall that divides the cylinder barrel into a pair of fluid chambers, the end wall of the floating piston having an aperture extending axially therethrough; and a main piston having a tubular portion slidably received through the open end of the cylinder barrel and through the aperture in the end wall of the floating piston such that the floating piston and main piston are slidable relative to each other, the floating piston and main piston cooperatively defining a fluid path between the two fluid chambers; and a lock-up valve operable to maintain said fluid path open so as to permit extension of the piston assembly during a portion of a stroke thereof until the strut reaches a predetermined lock-up length less than a maximum length thereof, and the lock-up valve sealingly engaging the main piston and the floating piston so as to close said fluid path when the strut reaches the predetermined lock-up length thus substantially preventing further extension of the piston assembly.