Patent ID: 6488072
Filing Date: 2002-12-03
Classification: B23Q

Abstract:
A dust cover comprising a plurality of shield plates which are equal in shape and progressively reduced in size, said shield plates being joined together to expand and retract along an axial direction; a linking device formed of a plurality of link rod units which have two rod members equal in length, said two rod members being pivoted together at the midpoint thereof such that two ends of said two rod members form a pair of opening-closing arms, two arms together at the midpoint thereof such that two ends of said two rod members form a pair of opening-closing arms, two arms of each one end of each link rod unit being pivoted with two arms of other link rod unit to form two pivoting points pivoted in the lower side of the same shield plate, wherein said shield plates are provided in the underside with a slide slot perpendicular to the moving axial direction of the dust cover; wherein said two pivoting points are provided with an insertion bolt respectively, the two insertion bolts are correspondingly pivoted in said slide slot of the same shield plate, so as to enable said two pivoting points to slide in said slide slot.