Lighthouse structure and compensating lens in reference laser beam projecting apparatus.

摘要

In an apparatus for projecting a laser beam (B) in a reference plane, a generally cylindrical, one-piece molded transparent lighthouse structure (26) overlies the rotatable pentaprism beam diverting assembly (14) of the apparatus. The lighthouse structure is mounted on a housing (12) so as to allow transmission therethrough of the rotating laser beam projected by the beam diverting assembly. The lighthouse structure has a tapered or conical configuration facilitating molding thereof. A continous resilient flexible ring (30) is adapted to attach releasably to the housing and fit tightly about the lighthouse structure for removably anchoring the structure to the housing in a sealed relationship, providing a water-tight enclosure for the beam diverting assembly and imposing a generally uniform attaching pressure about the lighthouse structure. A beam compensating lens (32) aligned across the laser beam and coupled with the beam diverting assembly for movement therewith. The lens is configured to correct the divergence in the laser beam which occurs when the beam passes through the one-piece molded lighthouse structure.