Abstract: A compact laser construction instrument intended for use by the average construction contractor. The instrument is capable of generating a rotating plane of laser light and a beam of light that is perpendicular to the rotating plane. It includes a beam generator adapted to generate a beam of collimated light along a given axis. A rotating platform is provided for supporting the beam generator for rotation in a plane parallel the axis of the collimated light and about a rotation axis that is perpendicular to the axis of the collimated light in order to generate a plane of light. A means is provided that is positioned for rotation with the platform for generating a second beam of collimated light along the rotation axis to generate a rotating narrow beam of light that is perpendicular to the plane.

Abstract: Self-leveling light beam projection apparatus for projecting and maintaining a beam of light along a predetermined path relative to the earth's vertical. A housing adapted for mounting in a predetermined plane includes a light source such as a laser generator for generating a collimated beam of light. A lens system including a pendulum mounting at least one lens is mounted for movement about mutually perpendicular axes to seek the vertical and to maintain the projected beam along the predetermined path despite the relative positions of the housing and light source.