Patent ID: 7475842

Claim:
A tape measure employing selectively engageable power operated tape extension, the tape measure comprising: a housing having a battery receiving chamber; a spring-biased tape assembly positioned within the housing and including: an annular reel; and a tape wound onto the annular reel, the tape having a bottom surface; a motor mounted within the housing and having a rotatable output shaft; a driving gear fixedly positioned on the output shaft; a transmission shaft rotatably mounted within the housing; a power transmission gear fixedly positioned on the transmission shaft for selective engagement with the driving gear to receive a torque from the output shaft; a drive mechanism, including a drive roller in contact with the bottom surface of the tape, for transmitting a torque from the transmission shaft to the tape to extend the tape out of the housing; an electrical circuit connecting the motor with the battery receiving chamber to selectively supply the motor with electrical power from at least one battery disposed within the receiving chamber; a tape extension switch coupled with the housing and electrically coupled with the electrical circuit, the tape extension switch being selectively moveable to open and close the electrical circuit for controlling the flow of electrical power from the at least one battery to the motor; and a clutch mechanism mounted on the housing for selectively axially displacing the transmission shaft to move the power transmission gear from a first position of engagement with the driving gear to a second position of disengagement from the driving gear to permit the spring-biasing of the tape assembly to retract the tape into the housing.