Patent ID: 8078236

Claim:
A rotary mechanism, comprising: a base defining a recess and a positioning post formed in the recess, an imaginary central line of the recess being colinear with an longitudinal axis of the post; a cover rotatably mounted to the base; a torsion spring, two ends of the torsion spring fixed to the base and cover respectively; a locking module including a spring and a locking member, the spring having a longitudinal axis co-linear with the imaginary central line of the recess and the longitudinal axis of the positioning post and received in the recess and placed around the positioning post, the locking member positioned on the spring and abutting against the cover, the locking member limiting the cover rotation relative to the base; wherein when the cover overcomes the limitation of the locking module, the cover automatically rotates relative to the base due to the torsion spring.