Twisting electrical test probe with controlled pointing accuracy

摘要

A spring biased test probe for testing electrical printed circuit boards includes an elongated tubular barrel having an open end, and a compression spring within a spring seating end of the barrel, opposite from its open end. A plunger inserted in the barrel reciprocates during testing, sliding within the barrel and biased by the spring pressure. The plunger includes a forward end portion outside the barrel, a slidable tail portion that contacts the spring and slides within a barrel, and an intermediate twisted portion between the forward end and the tail portion of the plunger. The forward end of the plunger has a probe tip configured to make frictional pressure contact with the board to be tested. The intermediate portion is twisted about its axis to form a spiral with helical grooves contacted by circumferentially spaced apart crimps in the side of the barrel, adjacent the open end of the barrel. The plunger is rotated about its axis by its contact with the crimps as the plunger travels axially in the barrel. The twisted intermediate section of the plunger and the forward end of the plunger extend outside the barrel which is contained in an elongated tubular outer receptacle. The forward end of the plunger includes an elongated enlarged diameter guide bearing section between the probe tip and the twisted section of the plunger.