"Autoclipse" optional non-dazzling acetylene motor car head lamp made to patent nos. 8091/05 and 5043/06

An "Autoclipse" optional, non-dazzling motor car head lamp, model 'C', patented by H. G. M. and M. A. Besnard in 1905-1906 (nos. 8091/05 and 5043/06). Using an arrangement of a hyperbolic reflector and a plano-convex lens, the acetylene lamp provides a central parallel beam for illuminating distant objects, and also a divergent beam for nearer objects. The central, dazzling beam can be cut out, or eclipsed, when required by a circular disc or shutter which, when operated from the dashboard, is brought into a position which stops light falling onto the reflector. It is border cable operated.

The beams of light are produced by the combination of a front plano-convex lens, and a rear hyperbolic reflector, the foci of which are coincident with the focus of the lens and the lamp flame. The light rays that fall upon the reflector are returned through the lens as though they are proceeded from its focus, thus forming a parallel beam; this arrangement permits the use of a lens of large diameter and great focal length in a lamp with very little depth. The rays that fall directly on the lens pass through it and emerge as a divergent beam, which lights up the road and surrounding near objects. In order to eclipse the central beam, a circular disc or shutter, normally housed in the top of the lamp, is brought down behind the flame so as to cut off all the rays that would fall upon the reflector. This disc is mounted on a swinging arm which is operated, through a Bowden wire, from a controlling lever mounted on the dashboard of the car. The lamp is fitted with an acetylene burner, and a filter is arranged at the bottom of the pillar which supports it. The body of the lamp connecting the lens with the reflector is of cylindrical form and blacked inside.

The example shown is 9.5 inches diameter, and is rated at 3,300 candle-power; its projective power is 560 ft.

Shown on right of image (with an acetylene generator, object number 1911-128 on left)