Probe pin
A probe pin includes a barrel having an internal space extending from one end to the other end, a plunger provided at the one end of the barrel, a plunger provided at the other end of the barrel, and a coil spring received in the barrel for supporting the plungers elastically. The coil spring includes a central portion having substantially same diameter, a first taper portion adjacent to one end of the central portion and having diameters decreased gradually, and a second taper portion adjacent to the other end of the central portion and having diameters decreased gradually.
1. 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.
2. The probe pin according to claim 1 , wherein a diameter d 1 of a final end of the second coil portion is smaller than a diameter d of the first coil portion and wherein a diameter d 2 of a final end of the third coil portion is smaller than the diameter d of the first coil portion.
3. The probe pin according to claim 2 , wherein the diameter d 1 of the final end of the second coil portion is equal with the diameter d 2 of the final end of the third coil portion.
4. The probe pin according to claim 1 , wherein the coil spring is symmetric with respect to a centerline orthogonal to the central axis of the first coil portion.
5. The probe pin according to claim 1 , wherein the coil spring is rotationally symmetric with respect to the center of a central axis of the first coil portion.
6. The probe pin according to claim 1 , wherein the first plunger comprises a cylindrical first contact portion having the same axis as the first sliding portion .
7. The probe pin according to claim 1 , wherein the second plunger comprises a cylindrical second contact portion having a same axis as the second sliding portion.
8. 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 respectively;
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 direction that is the same as 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.
9. The probe pin according to claim 8 , wherein a diameter dl of a final end of the second coil portion is smaller than a diameter d of the first coil portion and wherein a diameter d 2 of a final end of the third coil portion is smaller than the diameter d of the first coil portion.
10. The probe pin according to claim 9 , wherein the diameter dl of the final end of the second coil portion is equal with the diameter d 2 of the final end of the third coil portion.
11. The probe pin according to claim 8 , wherein the coil spring is symmetric with respect to a centerline orthogonal to the central axis of the first coil portion.
12. The probe pin according to claim 8 , wherein the coil spring is rotationally symmetric with respect to the center of a central axis of the first coil portion.
13. The probe pin according to claim 8 , wherein the first plunger comprises a cylindrical first contact portion having the same axis as the second sliding portion.