GB695892A - Improvements in or relating to undercarriages for aircraft - Google Patents

Abstract

695,892. Aircraft undercarriages. BRITISH MESSIER, Ltd. Sept. 5, 1951. [Nov. 21, 1950] No. 28469/50. Class 4. [Also in Group XXXIV] An aircraft undercarriage having a normal ground engaging wheel or the like is provided with an auxiliary ground wheel with a low pressure pneumatic tyre, means to fit it to the undercarriage alongside the normal ground engaging member so that it projects below said normal ground engaging member sufficiently to enable it to bear its due proportion of the load when on the ground, and means to release the auxiliary wheel and allow it to fall off the aircraft when in flight. The undercarriage leg 10 has a stub axle 11 which carries a permanent landing wheel 12 having a high pressure tyre 13. The wheel 12 has an annular flange 20 attached thereto which forms a spigot mounting for a further annular flange 21 secured to the hub 15 of an auxiliary low pressure wheel 16. A ring 23 is secured within the flange 20 and is formed with a plurality of spring fingers 24 formed at their free ends with enlarged bevelled heads 25, which, by virtue of the resilience of the fingers 24 may be sprung into and out of engagement with an inwardly projecting rim forming the outer wall of an annular recess 26 in the flange 21. The heads 25 are held in engagement with the co-operating rim by a locking bolt comprising a diaphragm 29 formed with a rim 32 having a flange 28. The rim 32 is capable of axial sliding movement within the flange 21 and is acted upon by springs 31 so that the flange 28 engages the inner faces of the fingers 24 to prevent inward movement thereof. The diaphragm 29 carries a central projection which is in contact with the end of the piston rod 35 of a piston 34 which slides within a cylinder formed in the axle 11 and is urged against the action of a spring 36 by pressure fluid admitted at 38. Initial movement of the piston and the locking bolt frees the fingers 24 and further movement brings the end 33 of the rim 32 into contact with a face 40 of the hub 15 thus separating the spigot connection 20, 21 and releasing the auxiliary wheel from the aircraft. Alternative embodiments are described in which the auxiliary wheel is mounted on the side of the leg opposite to the main wheel, Fig. 1 (not shown), or divided bogies may be releasibly secured on either side of the main landing wheel, Fig. 4, 5 (not shown).