Patent ID: 8128309

Claim:
A lifting device, comprising: a fixed member; a movable member movably mounted on the fixed member and having an elongate slideway, a plurality of locking grooves each connected to the slideway and an elongate guide slot parallel with the slideway; a locking bolt extending into the slideway of the movable member and detachably locked in one of the locking grooves of the movable member; a slide slidably mounted on the fixed member and secured on the locking bolt to move the locking bolt relative to the movable member; an elastic member biased between the slide and the fixed member to push the slide and the locking bolt toward one of the locking grooves of the movable member; a limit bolt movably mounted on the fixed member and extending into the guide slot of the movable member; a positioning member secured on the limit bolt to move in concert with the limit bolt and having a substantially inverted L-shaped locking slot that is movable to detachably lock the locking bolt; wherein the fixed member has a surface provided with an upright receiving recess to receive and allow movement of the positioning member; the receiving recess of the fixed member has a sidewall provided with a corrugated first contact face; the positioning member has an end portion provided with a corrugated second contact face slidably contacting with the first contact face of the fixed member.