Patent ID: 8587885

Claim:
A focusing device for a beam projector, the focusing device comprising: a casing; a body tube comprising at least one lens, the body tube being advanced or retracted in a direction of an optical axis in the casing; a movable member provided at a side of the body tube, the movable member moving in parallel to the direction of the optical axis; a bridge fixed to the body tube and coupled with the movable member to cover at least a part of the movable member, wherein the bridge comprises a second fixing piece extending from another end of the bridge to cover an outer circumferential surface of the movable member; and a drive motor fixed in the casing and located at a side of the body tube, wherein the movable member is screw-coupled with a drive shaft of the drive motor and the second fixing piece urges an inner circumferential surface of the movable member to closely contact an outer circumferential surface of the drive shaft by applying pressure to the movable member so that the movable member linearly reciprocates as the drive motor operates, whereby the body tube is advanced or retracted.