| 摘要 |
The disclosed invention provides a device for locating the center of an object o r an opening, the device comprising an annular member defining a central hole; opposing centering plates on opposite sides of the annular member; matching opposed notches in the centering plates, said notches open towards the annular member, the apexes of said notches being in lin e with the center of the central hole and an equal distance therefrom. Arms on the centering plate s have gears that mesh with gears on the circumference of the annular member, so that as the annul ar member turns, the apexes of the notches in the opposing centering plates move an equal and opposite distance along a line drawn through the apexes of the notches and the center of the central hole. To find the center of the end of a workpiece, the workpiece is placed between th e notches which are drawn together to hold the workpiece, and a pointed pin is placed through th e central hole to mark the center. The device may also be used to scribe a center line on a boa rd or such, and to find the center of an opening, such as a door or window opening.
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