GB911121A - Improvements in and relating to aircraft undercarriages - Google Patents

Abstract

911,121. Retractable undercarriages. ENGLISH ELECTRIC CO. Ltd. Jan. 29, 1960 [Feb. 5, 1959], No. 4170/59. Class 4. In an aircraft main undercarriage co-operating with a conventional nose wheel, the main wheels 1 are journalled in tandem arrangement in two closely spaced groups on the end of a beam 3 pivoted at one end to one end of a shockabsorber strut 4 slidable in a frame 5 which is rotatable about a transverse pivot axis 6 on the aircraft structure and on which a two-armed lever 10 is pivoted, one arm of lever 10 being articulated to the upper end of shock-absorber strut 4 and its other arm through another shockabsorber strut 12 to beam 3, the upper end of shock-absorber strut 4 being also linked to the aircraft by a radius rod 8. Frame 5, suspended on the centre line of the fuselage by a pivot 6, carries strut 4 pivotally attached by a pin 9 to one end of lever 10 and to the lower end of rod 8 mounted on the airframe by a fixed pivot 7. Lever 10, mounted on frame 5 by a pivot 11, is attached at its other end by a pivot pin 13 to one end of a shock absorber strut 12, the other end of which is attached by a pivot pin 14 to the beam 3, on which the wheels 1 are journalled by transverse axles 2 and 34. The axle 2 is fixedly mounted on the lower end of the strut 4 and permits pivotal movement of the beam 3 in a vertical plane. Frame 5 is also pivoted to a connecting rod 44, which is pivoted to the strut 16, itself rotatable about the joint 17 by operation of the jack 18. To provide lateral stability the frame 5 carries a pair of struts 22, 23 each arranged as a parallel linkage to support a bracket 26 on which is journalled an outrigger wheel 28, a shock absorber 30 being provided between frame 5 and each strut 22. To retract the undercarriage, the jack 18 is contracted, thereby folding connecting rod 44 and strut 16 about the joint 15 and rotating frame 5 about axle 6. This action causes strut 8 to swing the lever 10 about axle 11, and strut 12 will thereby turn the beam 3 into the position, Fig. 2 (not shown), in which the centres of the axles 2, 6 and 34 lie substantially in a straight line. Also, when the frame 5 is retracted, the shock absorber struts 30 cause the struts 22 to swing inwardly against stops 33, mounted on the frame 5. This position is reached when the line X-X has rotated to the position X 1 -X 1 . The strut 30 is then compressed upon further retraction of the frame 5 to its fully retracted position, Fig. 2 (not shown).