Patent ID: 6776565
Filing Date: 2004-08-17
Classification: F16B

Abstract:
A structure of an anti-burglar screw bolt having a washer and a nut, said bolt including a bolt head and a bolt shaft, wherein said bolt head is hexagonal and has inner edges being arranged with an equal angle, said bolt head and said nut are provided with a plurality of first sloping faces such that shallowest region of a fore notch of said first sloping faces is deepest region of a subsequent notch of said first sloping faces, connection region of each of said first sloping faces being a blocking face, said washer is flat and circular having a diameter equivalent to largest diameter of said bolt head, and a center of said washer is provided with a through hole having a hole diameter larger than diameter of said bolt shaft, one face of said washer is formed into a plurality of second sloping faces corresponding to said first sloping faces of said bolt head such that thinnest region of a fore one of said second sloping faces is thickest region of a subsequent one of said sloping faces and connection region of each of said second sloping faces is formed into a blocking face the other face of said washer is provided with a plurality of equally arranged sharp engaging ribs, each of said ribs has an upright face and a third sloping face and sloping direction of said third sloping face is similar to sloping direction of said second sloping faces of said washer, connection region of each of said first sloping face is formed with a blocking face, two opposite sides of said washer are each formed with a notch, whereby said bolt shaft passes through said washer and two working pieces in sequence, and in turn, a second washer being placed in a reverse position is passed through, and said screw nut is used to secure the two working pieces, said blocking face of said bolt head and said blocking faces of said nut will urge said blocking face of said washers to drive said washers in rotation.