GB1047011A - Improvements in or relating to manual control members - Google Patents

Abstract

1,047,011. Locking levers; toggle mechanisms. DE HAVILLAND AIRCRAFT CO. Ltd. Oct. 22, 1962 [Oct. 20, 1961], No. 37727/61. Headings F2E and F2K. [Also in Division B7] A manual control member, e.g. for setting an aircraft flap, is movable in a single plane between limit positions, and has one or more selected intermediate positions at which it is arrested by one-wayacting arrestor means, the member being releasable from an intermediate position by a to-and-fro movement of the member in a different plane when it is at that position. Fig. 2 is a view on Section A-A of Fig. 1, the control member being a lever pivoting about pin 11 for control movements, and composed of two parts 3, 4, pivoted together on pins 5, 6. Pivoting of part 3 on part 4 is normally prevented by a slot 12 in the housing 1, in which part 3 moves. A pawl 19 is pivoted on part 4 by pin 20, and has an arm forming a toggle linkage with a spring box 21 pivoted to part 4 at 22, so that either a tip 23 of the pawl contacts a ratchet segment 16, or a roller 24 journalled on an arm 19 contacts the ratchet, as shown. Part 4 contains a slider 7, which may be biased by a compression spring 8, having a roller 9 engaging a cam slot in part 3. The pin 25 of roller 24 projects so that it may be contacted by slider 7. When the lever is moved from right to left as seen in Fig. 1, with the pawl in the inoperative position shown, the roller 25 rides up on a tooth 18 on the ratchet, and trips the pawl to the operative position, in which tip 23 contacts the ratchet. The lever is then arrested when the tip 23 abuts the next tooth 18. To release the lever for further movement, recesses 14 are formed in the housing 1, so that a thickened part 13 of the lever is in register with a recess whenever the pawl tip 23 abuts a tooth 18. The operator then pivots the part 3 of the lever on pins 5, 6, so that the projection 13 enters recess 14, and cam slot 15 and roller 9 cause slider 7 to rise and strike pin 25, resetting the pawl to the inoperative position shown in Fig. 1. Part 3 of the lever is then returned to its normal position, and the lever can be advanced. On moving the lever from left to right, both roller 24 and tip 23 ride over the teeth 18, which are appropriately shaped so that such movement is not interrupted. A further pawl and ratchet are added if such movement is to be interrupted.