Month in the Patent Office

A cowling for aero‐engines or radiators has adjustable trailing edge louvres coupled with one another by a spreading ring, the diameter of which can be positively increased or reduced to obtain positive opening and closing of the louvres respectively. Alternate louvres 1, 2, Fig. 1, are secured to the edge of the cowling and to spreading ring 3, respectively, the edges of louvres 2 slidably engaging in double edges of flaps I. The ends of the ring 3 overlap and are each secured to one of a pair of chains 10, 11, Fig. 4, passing over parallel pairs of sprockets 6, 8 and 7, 9 mounted on axles 12, 13. Sprockets 7 and 8 are keyed to the axles and sprockets 6, 9 are free. Fast with the axles are housings 17, 18 bored to receive the ends of a pair of links 14, 15 pivotally connected to a common actuating member 19. The links are angularly disposed so that change in angularity accompanying axial movement of member 19 causes rotation of housings 17, 18 and the associated sprockets positively to expand or contract ring 3. The bearing brackets for the adjusting mechanism may be mounted on a ring 21.