GB673252A - Improvements relating to aircraft undercarriages - Google Patents

Abstract

673,252. Aircraft undercarriages. TRIGGS, W. W. (Geisse, J. H.). April 18, 1950, No. 9454/50. Class 4. An aircraft has two main wheels positioned one on each side of the aircraft axis, a castor mounting for each main wheel and means for urging said wheels into positions parallel with the aircraft axis, said means comprising stop means for preventing said wheels from nosing inward toward said axis and other means resiliently restraining said wheels from nosing outward from said axis. The aircraft 1 is supported on two main wheels 2 and a nose or tail wheel 10. Each wheel is free to castor and each main wheel 2 is supported in a fork 38 which is attached to the lower element of a resilient shock absorbing unit, of which the upper element comprises a shaft 29 having a lever 50 keyed thereto. Each lever 50 is urged by a spring 52 into contact with a stop 54 rigid with the aircraft structure so that each main wheel is normally held parallel to the longitudinal axis of the aircraft but is free to undertake a nose-out castoring movement only. When the aircraft lands in a cross wind therefore, one main wheel and the tail or nose wheel will castor in the appropriate direction while the other main wheel will be held parallel to the axis of the aircraft by the action of the arm 50 on the stop 54. In the embodiment shown in Fig. 6 each wheel supporting leg comprises a sleeve 27 mounted in a fixed part 25 of the aircraft structure. A bearing 32, clamped between the upper end of the tube 27 and a retainer 28, rotatively supports the shaft 29 which is recessed to accommodate a shock absorbing spring 41. The lower end of the spring rests within a sleeve 35 rigid with the wheel supporting fork 38, the sleeve sliding between the members 27 and 40 and being slotted at 37 to accommodate a pin 36 which is fast with the shaft 29 and limits sliding movement of the member 35. In a further embodiment, Figs. 8-10 (not shown), the lower element of the shock absorbing unit is connected to the upper element by a " jack-knife " linkage which limits the castoring movement to one direction only and in a still further embodiment, Figs. 11, 12 (not shown), each main wheel is supported on a structure in which the effective axis about which castoring action takes place is inclined downwardly forwardly, and outwardly.