US Patent 7003895 Tape measure having a self-powered reel assembly

A tape measure having a self-powered reel assembly and a housing for receiving the self-powered, reel assembly. The self-powered, reel assembly includes: a primary spool having a measuring tape wound upon the primary spool; a secondary biased spool assembly; and a coupler for connecting the primary spool to the secondary biased spool assembly for retracting the primary spool. In the preferred embodiment, the secondary biased spool assembly includes a spring spool, a spring drive spool, and a backwound spring.