OPTISCHER SPANNUNGSSENSOR FÜR EINEN SICHERHEITSGURT

A belt tension sensor (10/10') includes an armature (22) that is displaced in relation to belt tension and an optical sensing mechanism that detects armature displacement as a measure of belt tension. In a first mechanization, a lens element (38) is mounted on the armature (22) for movement therewith, and light emitted by a light source (34) passes through the lens element (38) before impinging on a light responsive element (36); the lens element (38) variably diffuses the emitted light in relation to the belt tension, and the light impinging on the light responsive element (36) provides a measure of the belt tension. In a second mechanization, the armature (22) includes a protuberance (52) that abuts and variably collapses a compressible optical waveguide (50) to vary its optical transmissivity in relation to the armature displacement, and the optical transmissivity of the optical waveguide (50) provides a measure of the belt tension.