GB534695A - Improvements in and relating to indicating instruments - Google Patents

Abstract

534,695. Indicating instrument. BENDIX AVIATION CORPORATION. Sept. 13, 1939, No. 25684. Convention date, Sept. 13, 1938. [Class 106 (iv)] A front closure for instruments of the pressure-responsive type comprises a rear retaining element 20 around the casing 10, a front retaining element 23 with an inwardly directed flange 24, a cover glass 17, means between the cover glass and a support surface 11 within the casing for resiliently supporting the cover glass, and means connecting the retaining elements so that the cover glass is maintained pressure-tight against the casing. A split resilient ring 12 is expanded into a groove in the casing 10 and supports a solid bevel ring 13. Above this ring is a sealing ring 13a of rubber &c. and above the sealing ring is a transparent ring 14 forming a window from which light from a source 30 at the side is projected on the dial 15. A ring-shaped bezel 16 of rubber abuts against the ring 14 and carries the coverglass 17. Surrounding the transparent ring 14 and separated therefrom by a circular shield 18 is a light conducting and emitting member 19. A ring 20 flanged to engage a shoulder 22 on the casing surrounds the latter and clamped thereto by screws 25 is a flanged ring 23 whose flange 24 engages the cover glass and clamps the various sealing rings together, the member 19 being located outside the sealed volume. A boss 26 is formed on ring 23 to receive a lamp assembly 27 screwed therein. The bulb of the lamp projects into a member 33 located between the ends of the split ring 31. In a modification the transparent member is in the form of a ring-shaped window member having at its outer circumference two surfaces, an upper surface adjacent the cover glass and which is transparent, and a lower surface which is covered with light - absorbing material, which in turn is covered with light-reflecting material. The front face of the transparent member is bevelled to direct the light rays from the exterior of said member on to the dial and the rear face is bevelled and coated with lightabsorbing material which in turn is coated with light-reflecting material. Specifications 482,595 and 523,085 are referred to.