GB498675A - Improved device for locking the control levers of carburettors of internal combustion engines in aircraft - Google Patents

Abstract

498,675. Spray carburetters. TAMPIER, R. July 6, 1937, Nos. 18769/37 and 1306/38. [Class 7 (iii)] In an aircraft carburetter having throttle and " mixture " levers operable independently of each other in some positions, the mixture lever may be looked in the " weak " position and be moved automatically or manually therefrom when the throttle lever is in a position in which the " normal " mixture position is essential. The throttle lever operates through a sliding rod 3 having a reduced portion in the lower face of which is an angular recess 6 opposite a recess 5 with inclined sides in the upper face of the rod. The reduced portion of the rod slides within and across a spring- pressed plunger 7 having a conical nose adapted to engage in either a recess 13 or aperture 12 in a sliding tube 4 forming part of the mixture control means. The tube is urged to the left or " normal " position by a spring 14 engaging an abutment 17 within the tube and having a lost-motion connection with a control tube 11. A conical shoulder 20 formed in the end of the tube 1 1 is adjacent the aperture 12. As shown in Fig. 1, with the throttle in the closed and the mixture lever in the normal position, the mixture lever cannot be moved as the plunger 7 is held in the recess 13 by the rod 3 which fits between the end of a fork on the plunger and a transverse pin 8. Movement of the throttle lever to the right, i.e. to the cruising position brings the recess 5 opposite the plunger 7 and the mixture lever can then be moved to the right to the weak position, compressing the spring 14; the plunger 7 enters the aperture 12 to lock the mixture control. If now the throttle is opened more, the inclined end of the recess 5 lifts the plunger 7 and the spring 14 returns the mixture control to the " normal '' position. Further movement of the throttle lever moves the recess 5 away from the plunger 7 and the rod 3 locks it in the recess 13. Two throttle rods 3 may be associated with a single mixture control 4 or the rods may be replaced by two rotatable discs co-operating with an intermediate fixed disc. In a modification, the recesses 6, 13 are omitted to give the throttle freedom of movement and the mixture control freedom unless the throttle is in the intermediate position and .the mixture control has been moved to the " weak " position. As shown in Fig. 5, a throttle lever 22 is formed with a cam member 27 having a recess 28 on its underside. A coaxial mixture lever 21 is urged to the normal position by a spring 23 and when the lever is moved to the " weak " position, a spring-pressed catch 31 thereon engages a fixed catch 30 if the throttle has been moved to its intermediate of " cruising " position permitting a roller 25 on the lever to enter the recess 28. The catch may be disengaged by depressing a knob on the mixture lever or by movement of the throttle lever displacing the roller 25 from the recess 28, the spring 23 then returning the mixture to the normal position.