GB526947A - Improvements in or relating to latching and locking mechanism, e.g. for the landing gear of aircraft - Google Patents

Abstract

526,947. Locking aircraft undercarriages. WESTLAND AIRCRAFT, Ltd., and COX, R. P. March 1, 1939, No. 6720. [Class 4] [Also in Group XXV] A latching and locking mechanism for a pivoted member, such as the wheel carrying arm of an aircraft landing-gear comprises means for limiting the angle through which pivotal movement can be effected, splines or their equivalent on a fixed member and the pivoted member which are encircled by or encircle an axially movable latching member, and safety-locking means serving to prevent movement of the latching member when the pivoted member is in either of its extreme positions. As shown, a member 10 forming the wheel-carrying arm of an aircraft undercarriage has a pivot member 5 rotating in a member 1, a projection 8 on a ring 7, keyed to the member 5, co-operating with a stop to limit the angular movement of the member 10. Splines 12 are formed on the member 5 adjacent to a collar 11 and similar splines 13 are formed on a member 20 keyed to the member 1. An internally splined sleeve 14 of the same axial length as the splines 12 can be moved to engage or disengage the splines 13 by a spanner member 16 mounted upon the sleeve 14 by a ball bearing 15. A projection 18 on the member 16 is adapted to enter notches 18a on the member 20 and three projections 19 are adapted to engage notches 19a in the collar 11. The width of the member 16 and projection 18 is equal to the axial distance between the member 20 and the collar 11. Fig. 3 shows the arm locked in one position. Upon moving the member 16 by a jack acting upon an arm 17 the projection 18 moves within the notch 18a, which is wider than the projection, until the inclined faces of the notch and projection cause the member 16 to move axially to engage the projections 19 with the notches 19a and disengage the sleeve 14 from the splines 13. Continued movement then rotates the arm 10 until stopped by the projection 8, whereupon continued rotation of the member 16 causes axial movement of the member 16 to bring the projection 18 into another notch 18a and the projections 19 into engagement with the surface of the collar 11. The splines may be replaced by polygonal surfaces or by keyways and the latching sleeve may be internal instead of external. The projections 18, 19 and their co-operating notches may be reversed and antifriction rollers may be provided on their surfaces. A rib and groove may replace the ball bearing 15, or these may be radial pins on the sleeve 14 engaging circumferential slots in the member 16, or the positions of these may be reversed. Rollers may be provided in the pins. The locking means may be applied to the retractable undercarriage arm described in Specification 526,946.