Electric lamp with a single device for focus-control and switch-control

Claim 1

An electric lighting lamp comprising: a first casing subassembly comprising a rotatably adjustable nut collar, a parabolic reflector joined to said rotatably adjustable nut collar and a transparent screen contained in said nut collar, said reflector defining a cylindrical opening arranged in the central portion thereof surrounded by an annular flange to allow passage of an electrical bulb therethrough upon rotation of said nut collar, the inside surface of said collar being threaded to form a nut; a second casing subassembly including a cylindrical container with an external thread on one end comprising a fixed tubular sleeve member having notches therein secured to said container for holding said electrical bulb, said second casing cooperating with said first casing subassembly so as to cause an axial translation displacement when said nut collar is rotated relative to said container, said first and second subassemblies being moved toward and away from one another during said displacement; switch means for connecting said bulb to an electric current source comprising a semi-stationary contact bridge extending transversely within an orifice of said sleeve member, and having a face cooperating in the closed position of said switch means with a connecting terminal for said bulb; elastic means for urging said semi-stationary contact bridge against said connecting terminal when the reflector of said first casing subassembly is moved between first and second axially translated positions of said displacement, defining a predetermined course for adjusting the light focus of said lighting lamp; and control means cooperating with said contact bridge which is automatically separated from said connecting terminal against the action of said elastic means, thereby opening the switch during further translation of said reflector toward an end position disposed outside said first and second positions of the adjustable light focus course.