Patent ID: 6856152

Claim:
A probe unit for measuring impedance for a printed wiring board, comprising: a probe having a first and a second contact styli to be contacted with a first and a second predetermined points on the printed wiring board, the styli being fixed to the probe with a resilient member; a turn disk having a turn center and a first position on a board-side face of the turn disk, the turn disk being formed to receive the probe at the first position; a turn device for turning the turn disk around the turn center such that the probe turns so that the contact styli turn substantially parallel to a measurement face of the printed wiring board; and a moving device for moving the probe toward the measurement face of the printed wiring board such that the first and second contact styli are contacted with the predetermined points; wherein the turn disk has a second position at which the probe can be disposed by being shifted from the first position; wherein the first position is farther from the turn center than the second position such that the probe is turned with a larger radius of curvature at the first position; wherein the turn disk and the turn device are moved together by the moving device; and wherein the turn device comprises: a motor causing a turning driving force; a belt transmitting the turning driving force; a pulley being connected to the turn disk and receiving the turning driving force from the belt such that the turn disk can be turned around the turn center; and a turn main body supporting the pulley rotatably with a bearing.