Patent ID: 7443157

Claim:
A device for testing planeness of an electrically conductive workpiece, comprising: a platform for supporting the workpiece thereon; a testing box movably fixed above the platform, the testing box having a contact pin fixed on a bottom surface of the testing box; a bracket mounted on the platform; a holding structure movably fixed to the bracket, the holding structure being connected to the testing box for driving the testing box to move up and down; an indicator; and a power supply, the contact pin being electrically wired in series with one electrode of the power supply, the platform being electrically wired in series with the other electrode of the power supply, the indicator being electrically wired in series with a testing circuit, which is made up of the power supply, the platform, and the contact pin; the contact pin being capable of being positioned above the platform at a distance which is equal to the sum of a thickness of the workpiece and a desired tolerance of the planeness, wherein if the planeness of the workpiece between the contact pin and the platform is out of the desired tolerance, the testing circuit is closed, conducting power to the indicator, which will then indicate that the workpiece is ineligible.