Patent ID: 7231722

Claim:
An apparatus for applying a plurality of regularly spaced marks to a surface comprising: a wire rope defining an interior void so that a predetermined applied tensile force causes said wire rope to compress radially and thereby produce a pretensioning limit beyond which said wire rope resists axial stretching; said wire rope having (i) a relaxed configuration, and (ii) a tensed configuration in which said predetermined tensile force is substantially axially applied to an end of said wire rope so as to thereby reach said pretensioning limit, said wire rope further having a length that is shorter in said relaxed configuration than in said tensed configuration; and a plurality of surface discontinuities spaced at predetermined intervals along a length of said wire rope, each of said surface discontinuities being receptive to a chalk so that said chalk is (a) selectively adhered to each of said surface discontinuities but (b) repelled by portions of said wire rope located between adjacent surface discontinuities thereby producing a multiplicity of aligned, accurately spaced chalk marks on a surface when said wire rope is snapped against said surface in said tensed configuration.