Chalk line holder

Claim 1

A chalk line holder, comprising A HOUSING HAVING A PARTITION DIVIDING THE HOUSING INTO TWO COMPARTMENTS, THE HOUSING HAVING AN APERTURE FORMED THERETHROUGH IN EACH COMPARTMENT FOR PASSAGE OF A CORRESPONDING CHALK LINE; A SHAFT; A PAIR OF SUSBSTANTIALLY COAXIALLY MOUNTED SPOOLS EACH ROTATABLY MOUNTED ON SAID SHAFT IN A CORRESPONDING ONE OF THE COMPARTMENTS, SAID SHAFT BEING AXIALLY SLIDABLE RELATIVE TO SAID SPOOLS; CHALK LINE OF A FIRST DESIRED COLOR WOUND ON ONE OF THE SPOOLS; CHALK LINE OF A SECOND DESIRED COLOR WOUND ON THE OTHER OF THE SPOOLS; COUPLING MEANS FOR SELECTIVELY COUPLING THE SHAFT TO A DESIRED ONE OF THE SPOOLS FOR SEPARATE ROTATION BY SAID SHAFT, THE COUPLING MEANS COMPRISING A SPLINE CONNECTION FOR EACH OF SAID SPOOLS, SAID SPLINE CONNECTION BEING COAXIALLY POSITIONED WITH THE SHAFT AND ANGULARLY DISPLACED FROM EACH OTHER IN PLANES PERPENDICULAR TO THE AXIS OF THE SHAFT WHEREBY AXIAL DISPLACEMENT OF THE SHAFT IN A PREDETERMINED DIRECTION ENGAGES A CORRESPONDING ONE OF THE SPLINE CONNECTIONS WITH A CORRESPONDING ONE OF THE SPOOLS FOR ROTATION OF SUCH SPOOL; AND HANDLE MEANS OUTSIDE THE HOUSING COUPLED TO THE SHAFT FOR MANUALLY ROTATING THE SPOOLS.