Abstract: A tightening device for positioning a worktable of a machine tool to a base includes a saddle member disposed on the base, and a positioning carrier member carrying the worktable and movable relative to an abutment wall of the saddle member. An elongate adjusting member has a force-delivering end spaced apart from the abutment wall, and a middle threaded segment threadedly engaged with the positioning carrier member such that the force-delivering end is movable towards or away from the abutment wall. A force transmitting member is loosely connected to the positioning carrier member, and is configured such that a spiral force resulting from a screw-in movement is taken up by a proximate end thereof from the force-delivering end, and is transformed to a translation force that moves a distal end thereof to tightly engage the abutment wall.

Abstract: An abutment plate assembly for a cutting machine includes an abutment plate unit, an extension plate unit, and a locking unit. The abutment plate unit includes a sliding rail unit having a generally T-shaped cross section. The extension plate unit is formed with a slide slot having a generally T-shaped cross section and engaging the sliding rail. The locking unit includes a pressing member movable vertically within the slide slot, a resilient member for biasing the pressing member to move away from the abutment plate unit, and a rotary lever unit. The rotary lever unit is rotatable so as to move the pressing member toward the abutment plate unit until the pressing member presses the extension plate against the abutment plate unit to thereby lock the extension plate unit on the abutment plate unit.