Patent ID: 8083552

Claim:
A probe pin comprising: a conductive housing having a first end and a second end opposite the first end, and a space extending from the first end to the second end being formed internally; a first conductive plunger provided at the first end; a second conductive plunger provided at the second end; and a coil spring received in the housing to elastically support the first and second plungers; wherein the coil spring comprises a first coil portion having first coils, a second coil portion having second coils and being connected adjacent to a first end of the first coil portion and a third coil portion having third coils connected adjacent to a second end of the first coil portion, the second end opposite the first end, wherein the first coils each have a substantially equal diameter, wherein the second coils comprise coils with gradually reduced diameters relative to the diameter of the first coil portion, wherein the third coils comprise coils with gradually reduced diameters relative to the diameter of the first coil portion, wherein the second coil portion extends diagonally from the first coil portion and the third coil portion extends diagonally from the first coil portion, wherein an end of the second coil portion is connected to the first plunger, wherein an end of the third coil portion is connected to the second plunger wherein a central axis of the second coil portion that connects centers of each coil crosses a central axis of the first coil portion and a central axis of the third coil portion that connects centers of each coil crosses the central axis of the first coil portion, the central axis of the second coil portion being diagonal to the central axis of the first coil portion and the central axis of the third coil portion being diagonal to the central axis of the first coil portion, wherein the first plunger includes a first cylindrical sliding portion and a first conical wedge with the same axis as the first sliding portion that is connected to the second coil portion and the second plunger includes a second cylindrical sliding portion and a second conical portion with the same axis as the second sliding portion that is connected to the third coil portion, and wherein the central axis of the second coil portion extends away from the central axis of the first coil portion in a first direction and the central axis of the third coil portion extends away from the central axis of the first coil portion in a second direction that is opposite the first direction; wherein a first angle formed by central axes of the first and second coil portions equals a second angle formed by central axes of the first and third coil portions.