| 摘要 |
A crime prevention screw that after the screw is tightened in predetermined places, an embedding material is embedded in a recessed portion composed of a square socket, a hexagon socket, a cross socket or a slot formed on a screw head so that the screw can be prevented from being drawn out with the intention of many pranks and malignant crimes, and an embedding material to be used for this crime prevention screw and the like are provided. Example of such crimes are car stealing through removal of a number plate of an automobile, resale and export of stolen automobiles, stealing and robbery or kidnapping using a stolen car, intrusion of a thief and a public enemy through a window into a house by means of drawing out of screws for fixing a grid to the window or screws for attaching a grid to a sash of the window. A crime prevention screw is constituted so that a recessed portion, for engaging and rotating an end of a tool such as a square bar spanner or a driver, composed of a square socket, a hexagon socket, a cross socket or a slot is formed on a screw head. A partial place of an inner wall of the recessed portion is formed with a recessed engagement portion into which one of an expanded portion which is obtained by buckling a part of an embedding material for embedding in the recessed portion at the time of the embedding and a protrusion to which a force directing to the side of the embedding material for embedding in the recessed portion is applied comes so that the embedding material is prevented from coming off.
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