When the compass is unused, the compass needle is bound by a sleeve and is positioned roughly. The supporting axle which is concentric with the sleeve is disengaged from the bearing of compass needle by gravity or elastic force. When it is used, the supporting axle is engaged with the bearing by useof external force and therefor it can prevent from unnecessary tear and wear. The structure of this invention is simple and sealed very well. The present invention possesses many forms e.g. it can be formed into button or be fitted on the handle of gun or knife, so that it will be convenient for soldiers. |