Patent attributes
An electronic measuring instrument includes a housing, a storage spool rotatably mounted to the housing, and a thin, flexible line provided on the storage spool and extendible from the housing for measuring distances. The storage spool is rotatable in a first direction for unwinding the line from the storage spool and a second direction for winding the line onto the storage spool. The instrument includes a rotatable drum in engagement with said line so that movement of said line causes movement of said rotatable drum. The instrument also includes a sensor, such as an optical sensor, in communication with the rotatable drum for sensing movement of the rotatable drum when unwinding the line from the storage spool and winding the line onto the storage spool, electronic circuitry in communication with the optical sensor for measuring distances based upon the sensed movement of the rotatable drum during unwinding and winding, and a spring-less, manually-operated crank assembly for winding the line onto the storage spool.
