The utility model provides a gear drive's mode locking brake device, includes band -type brake nut component and drive arrangement, band -type brake nut component embraces the claw including embracinga claw seat, first armful of claw and second, embracing claw seat center and having seted up the guide bar hole, first armful of claw and second are embraced and are formed the circular shape cavityafter the relative obvolvent of claw, this cavity and the same axle center in guide bar hole, first armful of claw and second are embraced a claw and are all articulated in embracing a claw seat, thearticulated shaft level, first armful of claw all is provided with pitch wheel portion with the articulated department that the claw was embraced to the second, can make first armful of claw and second embrace the claw when the rotation in step, drive arrangement's working beam articulates embraces the claw in first armful of claw or second, and drive arrangement is through working beam jack -up or first armful of claw of drive or the second armful claw of pulling back to make intermeshing's first armful of claw open or fold with a second armful claw.