GB547771A - Improvements in or relating to retractable undercarriages for aeroplanes - Google Patents

Abstract

547,771. Aircraft retractable undercarriages. OPPERMAN, S. E., and GANWICK ESTATES, Ltd. May 13, 1941, No. 6160. [Class 4] For facilitating the retraction of an aircraft undercarriage and for cushioning its fall a compressed air balancing cylinder and piston acts upon the retraction linkage with increasing moment throughout the whole range of movement as the undercarriage is raised. In one form, a wheel W is carried by the lower part O<SP>2</SP> of a jointed leg O<SP>1</SP>, O<SP>2</SP>, the junction O<SP>3</SP> being connected by a drag link D to one comer of a triangular frame pivoted to the aircraft at a second corner G and having its third corner connected by a link O<SP>4</SP> to the part O<SP>2</SP>. An extension 4 of the drag link D is connected at F to one end of a cylinder and plunger device 6, 6a pivoted at E to a fixed bracket 2 and supplied with compressed air from a reservoir 5. The triangular frame is moved to retract the wheel W by a strut A actuated by hand or by an electric or other motor M. Normally the pivots G, E and F are in a straight line, G being shown out of place in the drawing, but as the strut A is moved the balancing cylinder acts with increasing moment about the pivot G. In a modification the cylinder is made large enough to dispense with a separate reservoir. In another modification the balancing cylinder is arranged between the upper end of the leg member O<SP>1</SP> and the junction of the leg member O<SP>2</SP> with the link O<SP>4</SP>. Reference has been directed by the Comptroller to Specification 550,988.