To assure reliable locking and normal deployment of large space-born appendages, a type of lock-unlock mechanism driven by spring was proposed. The spiral spring was used as a retraction device to draw the clamp-band back due to its characteristics of storing much more energy in limited space. Centralized lock-unlock scheme was employed here to light down mass of the whole mechanism. Reliable retraction of the clamp band and no collision on the surface of satellite are inspection targets of retraction device. Effect on retraction track by varying the torque and mass of clamp band was presented in this paper. To some spaceborne flexible arm, simulation of retraction track was done under specified parameters. The result obtained from simulation reveals that clamp band can accomplish safely and reliably, and will not produce any spatial waste.