GB213974A - An improvement in electric hand lamps - Google Patents

Abstract

213,974. Coulson, W. T. Jan. 10, 1923. Electric-lamp lanterns; lantern shutters.-In an electric hand lamp, the bulb is carried on a rocking plate actuated by means of a push button so as to move the lamp with regard to its lens or reflector for controlling the width of beam. The plate may carry a switch contact and have means for holding the switch permanently closed. Figs. 2 and 4 shows alternative forms inverted with respect to their normal position, i.e. the lamp normally hangs downwards behind the lens L, Fig. 1. The lamp-holder is mounted on a plate s, pivoted at b in fixed members p, r so that when one or other of the projecting push-pieces n, n is pressed the lamp swings along the axis of the lens. The plate is maintained in its central position by a leaf-spring and the extent of its movement is determined by a screw g carried by an insulating block o on the top of the plate and abutting on one or other side of a hole a in the member p when the plate s rocks. The screw g may carry one of the conductors at f, Fig. 4, the lamp circuit being completed through the member p which thus acts as a switch. To keep the switch closed, an additional screw m may be carried in the block o, the pointed end of which is normally free in a hole c in the member p and rides into a conical hole in the springy member p when the plate s is rocked. In the form shown in Fig. 5, the lamp is mounted upright on the plate s which has holes passing loosely over the terminals u. The plate is rocked by means of push-pieces t against the action of springs held down by the terminal nuts, one or other of two upstanding metal fingers v making contact with the terminal nut to close the circuit in the two positions of the lamp. A hold-on switch action may be obtained by bending over the ends of the fingers v so that they will enter a slot in the nut. A vertical rotary cylinder with coloured windows may be attached to the cover in this form, with an external index to show which colour screen is acting. A spherical reflector may be mounted on the plate to move with the lamp or also a fixed parabolic reflector may be employed, in which case the lamp is arranged at right-angles to the position shown in Figs. 2 and 4, and it moves axially through a hole in the reflector. Alternatively, the bulb may be fixed and the lens or reflector may be moved with respect to it. When an accumulator is used it may be confined to a separate compartment to which the leads from the rocking mechanism pass through an airtight joint.