Patent ID: 7114264

Claim:
A rafter square, comprising: a triangular plate, having a flanged base edge, a side edge and a hypotenuse edge having a length that extends between a distal end of said base edge and a distal end of said side edge; an elongated extension arm, having opposite first and second end portions, positioned adjacent and along said hypotenuse edge; said extension arm being selectively movable between a retracted position, adjacent and along said hypotenuse edge, and an extended position that places at least a portion of a marking edge of said extension arm in-line with, but beyond the distal end of, said side edge; said extension arm moving between said retracted position and said extended position about a pivot point adjacent the distal end of said side edge; and locking means for selectively securing said extension arm in said extended position; said locking means being comprised of an opening formed within said extension arm that is sized and shaped to receive a pivot pin adjacent the distal end of said side edge so that said extension arm may first be pivotally moved from said retracted position to said extended position and them moved longitudinally toward said base edge; said locking means is further comprised of a pocket formed within said plate, adjacent the distal end of said side portion; said pocket being shaped and sized to releasably receive a projection formed into an end portion of said extension arm.