Patent ID: 6191547
Filing Date: 2001-02-20
Classification: B60Q,B64D,F21S,F21V,F21W

Abstract:
A focus control for narrowing and widening the focus angle of a search light beam emitted by a search light mounted on a platform having a power source, wherein the search light includes an electric motor, a cam driveable by the motor to rotate and a focus control operated by the cam for narrowing and widening the focus angle in response to control signals over a single wire interface between a remotely positioned control switch and the motor, the focus control comprising:an open position, a power source position and a ground position selectively assumable by the remotely positioned control switch, wherein when the remotely positioned control switch is in the power source position, the single wire interface is in a first state different from a second state of the single wire interface which occurs when the remotely positioned control switch is in the ground position, anda switching circuit connected between the power source and the motor for reversing polarity of current flowing through the motor, the switching circuit being connected to the remotely positioned control switch by the single wire interface and including an input responsive to a change in state on the single wire interface to reverse the polarity of current flowing through the motor to reverse rotational direction of the motor, whereby when the cam reverses rotational direction thereby reversing the widening or narrowing of the focus angle.