TW200724859A - Auto-rewind structure of tape measure for dwindling case, lessening weight and extending tape - Google Patents

Abstract

The aim of the present invention is to provide an auto-rewind structure of tape measure, which is capable of providing longer length of tape, smaller case, lighter weight and faster rewind than a traditional one. The structure of the tape measure comprises a case (1), a roll (2) disposed in the case, a tape (3) wound around the roll, a rewinding device (4) disposed in the roll, a shaft (5) penetrating through the rewinding device, a base plate (6) located at a side end of the rewinding device and a small gear (7) located at the center of the base plate. A rolling wheel (42) is disposed with a spiral spring (44) therein and with inner ring teeth (422) on its side, and the base plate (6) is disposed with a gear set (61), so as to be engaged with the inner ring teeth (422) described above. Furthermore, the small gear (7) is also engaged with the gear set (61), and after actuated by the shaft (5) or the roll (2), the gear set (61) can drive the rolling wheel (42) to curl the scrolling spring (44).