Headlight permissible for use in explosive atmospheres

摘要

Headlight comprises a hollow metal housing with a circular rim defining a forward opening. A side outlet socket assembly is provided in the housing, at the rearward end, to receive the transverse pins of a side-pin style bulb. The housing rim has external threads on the outside and a conical, tapered surface on the inside. A separate bulb and lens retainer ring has an external conical, tapered surface, sealingly engageable with the conical surface in the housing rim to provide a tapered flame path in the event of an internal explosion and also allows easy removal of the bulb and lens. The bulb and lens retainer ring has an inner bore with counterbores at the front and rear ends. A rubberlike ring in the rear counterbore provides an elastic seat for a flange on the front of the bulb and cushions it against shock. A heavy lens is potted by epoxy, or otherwise permanently sealed into the front counterbore. A generally U- or V-shaped spring bail has a flat intermediate portion pressed across the rear end of the bulb base and has two transverse tine portions engaged within diametrically opposed holes in the bulb and lens retainer ring to hold the bulb, retainer ring, and lens as a separately removable and replaceable sub-assembly. A front cover ring has internal threads engageable with the external threads on the housing rim and has a radially inwardly extending flange engageable with the front edge of the bulb and lens retainer ring to press the conical surfaces into sealing, explosion-proof engagement when the cover ring is tightened.