Patent ID: 7111408

Claim:
A folding rule, comprising: a plurality of hydrophobic segments having length indicating indicia thereon, including a first end segment and second end segment and a plurality of intermediate segments, the hydrophobic segments formed of a generally homogenous electrically non-conductive mixture of wood and ABS plastic; the intermediate segments having a length to thickness ratio in the range of 40:1 to 60:1 and each of the intermediate segments comprising a first hole disposed toward a first end thereof and a second hole disposed toward a second opposite end thereof; the intermediate segments pivotally connected together at respective pivot joints via a plurality of posts each extending through the first hole of a first intermediate segment of the joint and the second hole of an adjacent intermediate segment of the joint; wherein the intermediate segments forming each pivot joint are biased toward one another; at least the intermediate segments pivotally moveable between a collapsed configuration wherein the intermediate segments are stacked and an extended configuration wherein the intermediate segments are linearly aligned along a measurement axis, wherein at least one intermediate segment rotates by approximately 180° with respect to an adjacent intermediate segment to move between the collapsed configuration and the extended configuration; the intermediate segments each further comprising a plurality of protrusions extending normal to the measurement axis and disposed proximate the first hole and a plurality of recesses extending normal to the measurement axis and disposed proximate the second hole; wherein the protrusions and the recesses are complementarily formed.