GB610698A - Improvements in or relating to retractable undercarriages - Google Patents

Abstract

610,698. Retractable undercarriages. FAIREY AVIATION CO., Ltd., CHAPLIN, H. E., and BEALE, R. D. April 15, 1946, No. 11514. [Class 4] The leg of a retractable undercarriage comprises telescopic portions 15, 16 which are moved relatively during the retraction movement, to shorten the length of the leg in the stowed position, by toggle links 20, 22a, the latter forming one arm of a bell crank, the other arm 22b of which is connected to one end of a link 34 whose other end is pivoted at 35 to a knucklejointed strut 24, 25. The point of connection 35 is a short distance above the knuckle joint 28 of the strut, whereby during retraction of the undercarriage leg by a jack 31, the link 34 moves the arm 22b to break the toggle joint 21 of the links 20, 22a, and thus telescope the member 15 within the member 14. The members 14, 15 may be provided with helical splines 16, whereby the landing wheel 13 is turned through a right-angle during retraction, so that in the stowed position 13a its plane is substantially horizontal. The inner member 15 forms the cylinder of a hydraulic shock absorber, the plunger 17 of which carries the wheel 13. Fig. 3 shows an alternative form of toggle linkage in which the points of connection 19a, 23a of the links with the telescopic leg portions are offset from the centre line A-A of the leg, and the links are formed with faces 38, 40 arranged normally to abut against shoulders 39, 41 on the leg portions, this form constituting a toggle which is not readily displaced, and which is suitable for use on heavily-loaded undercarriages.