JPH0119334Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to the improvement of contact pins used, for example, in carrying out current testing of printed circuit boards.

BACKGROUND ART When conducting a current conduction test on a printed circuit board, a predetermined number of conductive contact pins are embedded in an insulating plate slightly larger than the printed circuit board, and the insulating plate is brought close to the printed circuit board. Then, one end of the contact pin is pressed into contact with the conductive part of the printed circuit board, the circuit connected to the other end of the contact pin is connected to the printed circuit board via the contact pin, and the printed circuit board cooperates with the circuit to move into a predetermined position. This is a test to see if the following actions can be performed.

Conventionally, the contact pin shown in FIG. 1 or 2 has been used. In Figure 1, contact pin 1
0 is the sleeve 11, plunger 12, and connection part 13
, a contact portion 14 and a spring 15. The sleeve 11 is made of synthetic resin or metal and has a cylindrical shape. The outer diameter of the sleeve 11 has three levels, with one end 16 having the largest thickness, the other end 17 having the smallest thickness, and the center 18 having an intermediate thickness. The inside has a bore 19 . The plunger 12 is made of metal, has a connecting part 13 and a contact part 14 integrally formed at both ends, and has an outer diameter of the connecting part 13.
has the smallest thickness, the contact portion 14 has the largest thickness, and the center 20 has an intermediate thickness, and the center 20 is slidably inserted into the inner hole 19 of the plunger. After the sleeve 11 is inserted from one end 16 into the inner hole 19 from the connection part 13 side of the plunger 12, a coil spring 22 is attached to the other end 17 of the sleeve and the end 21 of the connection part 13 at the center 20 of the plunger.
Both ends 23 and 24 of are locked. Irregularities 25 are formed on the end surface of the contact portion 14 . The center 18 of the sleeve is supported by an insulating board for the current conduction test, a lead wire is connected to the connecting part 13 of the plunger, the insulating board is brought close to the printed circuit board supported facing the contact part 14, and the connecting part 13 is printed. Abut against the conductive part of the substrate. When the connection part 13 is abutted against the conductive part of the printed circuit board, the plunger 12 is moved along the inner bore 19 of the sleeve in the opposite direction towards the connection part 13. Then, the coil spring 22 is expanded, and the reaction force presses the connecting portion 13 more strongly against the conductive portion of the printed circuit board, thereby ensuring the exchange of electrical signals between the two.

However, the one shown in Fig. 1 has the drawback that the lead wire of the connecting portion 13 is moved every time the plunger 12 moves up and down, and stress from expansion, contraction or bending is applied to the lead wire, resulting in accidents such as wire breakage. .

FIG. 2 shows an improved version of this, and the same parts as those in FIG.
The difference is that the sleeve 11 is a blind hole that penetrates the inner hole 19 only at one end 16, and the connecting part 13 is connected to the sleeve 11.
formed at the other end of the One end of the plunger 12 is inserted into the inner hole 19, and the coil spring 22 is inserted between the bottom surface 26 of the inner hole 19 and one end 27 of the plunger. A caulk 28 is formed on the sleeve 11 to restrict the amount by which the plunger 12 moves from the inner hole 19 toward the one end 16. The sleeve 11, the plunger 12, and the coil spring 22 are made of metal, and the inner hole 19 of the sleeve, the coil spring 22, and the plunger 1 are made of metal.
Transmission of electrical signals takes place through contact between the two.

The contact pin 10 in FIG.
8 is supported on an insulating substrate. When the contact portion 14 of the plunger abuts against the conductive portion of the printed circuit board, the plunger 12 is pressed against the conductive portion by the force of the coil spring 22.

However, the device shown in FIG. 2 has the disadvantage that if rust develops or oil etc. adheres to the inner hole 19 of the sleeve, the electrical signal transmission becomes uncertain and reliability deteriorates.

Disclosure of the invention This invention was proposed in consideration of the above points, and it does not apply stress to the lead wire and is reliable even if rust forms in the inner hole of the sleeve or oil etc. adheres to it. It is an object of the present invention to provide a contact pin with a simple structure that does not reduce performance.

In the present invention, the coil spring is housed in the inner hole of the sleeve. A plunger having a contact portion is removably inserted into one end of the inner hole of the sleeve. A connecting portion is inserted through the other end of the inner bore of the sleeve. At the plunger and the connecting portion, a cylindrical portion is formed in a portion extending into the inner hole of the sleeve into which both ends of the coil spring are inserted and locked. The plunger is movably supported at one end of the sleeve inner hole via a coil spring, and the connection portion is E
It is locked to the other end of the sleeve inner hole with a mold retaining ring or the like.

According to the present invention, the connection part is not moved together with the plunger and no stress is applied to the lead wire. The coil spring inserted into the inner hole of the sleeve is inserted into and connected to the cylindrical part formed at the connecting part with the plunger, and the connection is ensured. Then, if necessary, a threading groove into which a cylindrical coil spring is threaded can be formed or soldered. As a result, even if there is rust or oil in the inner hole, connection failure will not occur, and reliability is high.

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 3 shows an embodiment of the invention, and the same parts as in FIGS. 1 and 2 are given the same reference numerals.

The sleeve 11 is made of metal or synthetic resin,
It has an inner hole 19. The inner hole 19 has an opening with the same diameter at one end 16 and an opening 29 with a slightly smaller diameter at the other end.
has. The plunger 12 has a large diameter contact portion 14 at one end, a small diameter connection portion 27 at the other end, and a center 28
is the intermediate diameter and is slidable into the inner diameter 19.

The connecting portion 13 has a small diameter portion 30 that is inserted into the opening 29.
It has a large diameter portion 31 that slides into the inner diameter 19 and is larger than the opening 29, and a cylindrical connecting portion 32 that protrudes from the large diameter portion 31 in a direction opposite to the small diameter portion 30. Connection part 2
The ends of the coil springs 22 can be fitted and locked into the coil springs 7 and 32 by the elasticity of the coil springs 22, respectively. Screw grooves 33 and 34 into which the end portions of the coil spring 22 are screwed are formed in the connecting portions 27 and 32 as necessary to further ensure the locking. Further, after the connecting parts 27, 32 and the ends of the coil spring 22 are fitted, they can be soldered to ensure secure locking.

The connection part 13 has a coil spring 22 and a plunger 12.
After being connected linearly with the sleeve, the sleeve is inserted into the inner hole 19 of the sleeve from the end 16 and then passed through the opening 29.
Then, the E-shaped retaining ring 33 is engaged with a groove formed at the root of the small diameter portion 30 outside the opening 29, and is prevented from coming off and locked.

Both ends of the coil spring 22 can be fitted into the connecting parts 27 and 32, and the coil spring 22 is wound to a diameter that allows it to be inserted into the inner hole 19. Further, the length is formed to be shorter than that of the inner hole 19.

According to the contact pin 10 of the present invention, both ends of the coil spring 22 are inserted into the cylindrical connecting parts 27 and 32 formed on the plunger 12 and the connecting part 30, and are connected by fitting. At this time, the elasticity of the coil spring 22 can be used to fit them together. It is also possible to solder the coil spring 22 with both ends fitted into the connecting parts 27 and 32. Furthermore, the connection parts 27, 3
It is also possible to form a spiral groove (thread groove) in 2 into which both ends of the coil spring 22 can be screwed together. This can improve reliability. Only the plunger 12 moves, and the connecting part 13 is not moved, so that stress is not applied to the lead wire connected to it, and the lead wire will not be disconnected. A printed board can be connected and fixed instead of this lead wire. Furthermore, even if the inner diameter 19 becomes rusty or contaminated with oil or the like, there is no risk of poor conductivity and reduced reliability.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional side view of a conventional example, FIG. 2 is a sectional view of another conventional example, and FIG. 3 is a sectional view of an embodiment of the present invention. 12 is a plunger, 14 is a contact portion, 27, 32
11 is a sleeve, 19 is an inner hole, 13 is a connecting portion, and 22 is a spring.

Claims (1)

[Claims for Utility Model Registration] A plunger having a contact portion at one end of a cylindrical body formed of a conductive material and a spring connection portion having a smaller diameter than the cylindrical body at the other end, and a non-conductive material or conductive material. a sleeve made of a flexible material and having an inner hole into which the spring connection part and the cylindrical body of the plunger are inserted so as to be removable; and the sleeve is inserted into the inner hole from one end of the sleeve;
one end of the sleeve is supported by protruding from the other end of the sleeve, the other end has a spring connection portion extending toward the one end of the sleeve in an inner hole of the sleeve, and the connection portion is made of a conductive material; a spring formed of an electrically conductive and elastic material, inserted into the inner hole from one end, connected at both ends to a spring connection part of the connection part and a spring connection part of the plunger.