Contractable shock absorber strut

DETAILED DESCRIPTION Referring more particularly to the drawings, the structure of the preferred embodiment of the invention will be described.
The numeral 10 designates a portion of an aircraft component in the area of a landing gear unit 11 thereof.
A door, 12 is hinged as at 13 to the component 10 and adapted to be swung relative thereto by means of and through an actuator and linkage 14 to and from extreme positions where it overlies and encloses an opening 15 in the component 10 and is disposed outwardly therefrom.
The gear 11 is mounted in any conventional manner to structure within the component 10 for movement to and from extreme positions of retraction totally within the component 10 and extension totally outwardly of the component 10.
To this end a power actuator for example, a screw jack 16 may be employed which is driven by a suitable motor 17.
More specifically, a ball screw 18 is secured at opposite ends to fixed structure 19 within the component 10 and is rotatable through a drive shaft 20 and universal joints 21 between its upper end and the motor 17.
A ball nut 22 operative on the ball screw 18 connects to the gear 11.
Thus the gear 11 is moved vertically to and from the extreme positions illustrated in FIG.
1 in phantom and solid lines to locate the gear 11 and its associated wheel 23 in the stowed and extended positions respectively.
In so moving, the gear 11 passes through the opening 15 which is opened and closed by operation of the actuator 14 and movement of the door 12.
Essentially, the gear 11 includes a shock absorber strut formed by a outer cylinder 24 at its upper or inner end and a piston 25 at its lower or outer end.
The cylinder 24 is connected to the screw jack 16 through the ball nut 22 while the lower end of the piston 25 connects through an axle 26 to the wheel 23.
The piston 25 is slideable in the cylinder 24 being formed or otherwise provided with a peripheral bearing 27 at its inner end having a peripheral surface 28 slideable on and against the inner cylinder wall 24'