JPH026372Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a circuit test needle for determining the quality of electronic circuits such as printed circuits.

[Technical background of the invention]

As shown in FIG. 1, a conventionally used circuit testing needle has a terminal 2 fixed to the end of a conductive outer tube 1, and a compression coil spring 3 connected to the terminal 2 inside the outer tube 1. The body portion 5 of the contact needle 4 facing each other is fitted so as to be movable in the axial direction, and the contact needle 4 is disposed between the inner diameter of the outer tube 1 and the outer diameter of the body portion 5 of the contact needle 4. Since the main body portion 5 of the main body 5 slides in the axial direction, there is a slight gap. The circuit test needles used to determine the quality of electronic circuits such as printed circuits are arranged and fixed on an insulating board such as synthetic resin in the same pattern as the circuit, and are arranged and fixed on an insulating board such as synthetic resin. By pressing the individual contact needles 4 against the test points of each circuit, the test current flowing through the circuit is extracted. This extracted current is applied to the spring 3
The current reaches the terminal 2 through the point or surface where the outer tube 1 and the contact needle 4 make contact, and supplies the current necessary for circuit testing.

In this conventional circuit inspection needle, the side surface of the contact needle 4 is pressed against the inner wall of the outer tube 1 by an uneven load due to buckling of the spring 3, etc., and that part forms a current circuit. During use, the contact position and posture change each time, and the contact resistance between the inner wall of the outer tube 1 and the outer surface of the contact needle 4 changes, making it difficult to obtain uniform test results in terms of accuracy. There is. In addition, as the number of repeated uses increases, the contact resistance changes due to wear due to friction between the inner wall of the outer tube 1 and the outer surface of the contact needle 4, and the inspection is subject to problems such as wear particles generated due to wear. reliability may be impaired.

On the other hand, as shown in Japanese Utility Model Application Publication No. 53-96871, a movable element is fitted inside the guide so as to be slidable in the axial direction, and a movable element is built into the guide at one end of the movable element. An axial spring is brought into contact with the movable element, a contact element is integrally provided at the opposite end, and a horizontal hole with a bottom is provided in a direction intersecting the axial direction of the movable element. There is a meter reading device that is fitted with a The purpose of this structure is to press the movable element in a direction intersecting the axial direction using a small spring, thereby bringing the movable element into sufficient contact with the guide and stabilizing the electrical resistance.

[Problems with background technology]

However, the meter reading device described in the above publication also has the same problems as the conventional example shown in FIG. 1, as described below.

In other words, in this type of test device, it is important that the force pressing the contact against the test object is a predetermined axial force designed by the axial spring.
Due to the reaction force of the small spring, a contact resistance force (not constant) is exerted between one side of the large diameter part of the mover (the side opposite to the ball) and the guide, so the designed axial force is This makes it difficult to obtain uniform test results and reduces the reliability of inspections and tests.

Further, the portion where the large-diameter portion of the movable element and the guide come into sliding contact is subject to uneven wear due to the pressing action of the small spring, so wear particles are likely to be generated, and the service life of the movable member is relatively short. In addition, if wear particles are generated due to repeated friction, this wear particle will cause current loss between the contact and the lead wire, impairing the reliability of inspections and tests, and eventually becoming insulated and becoming unusable. There is even a possibility that this will happen.

[Purpose of invention]

The purpose of the present invention is to eliminate changes in contact resistance within a circuit test needle, extract a stable test current, and enable accurate measurements.

[Structure of the idea]

(Means for Solving the Problems) The present invention fixes the terminal 12 to the end of the outer tube 11, and provides a spring 1 for the terminal 12 inside the outer tube 11.
In the circuit inspection needle, the main body portion 18 of the contact needle 17 facing each other via the contact needle 6 is fitted so as to be movable in the axial direction.
Holes 21 perpendicular to the axis are formed through the upper and lower parts of the main body 18 of the contact needle 17, and springs 23 are inserted into the upper and lower holes 21, respectively.
Balls 24 are provided at both ends of each spring 23 to be pressed against the inner wall of the outer tube 11.

(Function) The present invention provides balls 24 located at both ends of the spring 23 in each of the upper and lower parts of the main body 18.
is always kept on the inner wall of the outer tube 11 by the pressure of the spring 23, and rolls smoothly on this inner wall, so that the outer tube 11
A stable contact force can be obtained between the ball 24 and the ball 24, and stable inspection can be performed. Moreover, in each of the upper and lower parts of the main body part 18,
The plurality of balls 24 smoothly roll on the inner wall of the outer tube 11,
Since the inner wall of the outer tube 11 and the main body portion 18 of the contact needle 17 do not come into direct contact, abrasion powder is less likely to be generated.

[Example of idea]

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in FIG. 2 and subsequent figures.

As shown in FIG. 2, an outer tube 1 made of conductive metal
The base 13 of the terminal 12 is fitted to the upper end of the outer tube 11, and the outer tube 11 is inserted into the V-groove 14 provided on the circumferential surface of the base 13.
The terminal 12 is fixed by fitting the caulking part 15 on the upper part of the terminal. Further, the terminal 12 is provided inside the outer tube 11.
The body part 18 of the contact needle 17 facing the body part 18 of the contact needle 17 is fitted into the body part 18 of the contact needle 17 facing each other via the compression coil spring 16 so as to be movable in the axial direction. The small diameter portion 20 is fitted into the large diameter portion, and the large diameter portion is locked. Further, as shown in FIGS. 2 and 3, a hole 21 perpendicular to the axis is bored through the upper and lower parts of the main body 18 of the contact needle 17 from one side to the other side. A conical spherical seat 22 is provided on both sides, and a hole 21 is provided.
A compression coil spring 23 is inserted into the center of the outer tube 11, and a ball 24 made of metal or the like is fitted to both ends of the spring 23, and the contact needle 1 is inserted into the outer tube 11.
Incorporate with 7. This ball 24 is always pressed against the inner wall of the outer tube 11 by the pressure of the spring 23 and is able to roll.

Then, when the tip of the contact needle 17 is crimped to the test point of the circuit, the contact needle 17 retreats into the outer tube 11 against the spring 16 while the ball 24 rolls, and is taken out from the contact needle 17. The current is sent to the tester body via the outer tube 11 and the terminal 12, or via the spring 16 and the terminal 12, or along the path of the spring 23, the metal ball 24, the outer tube 11 and the terminal 12.

In recent years, circuit inspections have required high speed and accuracy, and inspections using high-frequency currents have been carried out, which requires a reduction in the specific resistance of circuit inspection needles. In this respect, when using a conventional test needle that does not have the structure of the present invention, the initial (beginning of use)
The specific resistance of is approximately 30 milliohms, but after repeated use of 300,000 times, it reaches a minimum of 100 milliohms and a maximum of insulated state, and after 500,000 cycles of use, it often fails to withstand the use. On the other hand, with the device of the present invention, the initial resistance of about 30 milliohms did not exceed 50 milliohms even after 300,000 repetitions.
The value hardly changes even after repeated use 500,000 times, except in the case of spring breakage after 1 million times use.
Experiments have shown that the resistivity can be kept below 100 milliohms.

Next, FIG. 4 shows a modification of the present invention, in which the spring 2
3a and four sets of balls 24a are provided at one location.

[Effect of idea]

According to the present invention, holes perpendicular to the axis are formed in the upper and lower parts of the main body of the contact needle incorporated inside the outer tube, and springs are inserted into the upper and upper holes, respectively. Balls were provided at both ends of each spring, and these balls were brought into pressure contact with the inner wall of the outer tube, so that the plurality of balls smoothly rolled on the inner wall of the outer tube at the upper and lower parts of the main body of the contact needle. A stable contact force can be obtained between the outer tube and the ball due to the pressure of the spring, and a stable test current can be obtained without changes in contact resistance, allowing accurate measurement. This increases the reliability of the test. In addition, multiple balls roll smoothly on the inner wall of the outer tube at each of the upper and lower parts of the main body, and the contact needle does not come into direct contact with the inner wall of the outer tube, so wear particles are less likely to be generated. . This greatly increases the lifespan of repeated use.

[Brief explanation of drawings]

Figure 1 is a sectional view showing a conventional circuit inspection needle, Figure 2
The figure is a cross-sectional view showing one embodiment of the circuit test needle according to the present invention, FIG. 3 is a cross-sectional view taken along the - line in FIG.
The figure is a sectional view showing a modification of the part in FIG. 3. 11...outer tube, 12...terminal, 16...spring,
17... Contact needle, 18... Main body, 21... Hole,
23...spring, 24...ball.

Claims (1)

[Scope of utility model registration request] In a circuit testing needle, a terminal is fixed to the end of an outer tube, and a main body of a contact needle, which faces the terminal via a spring, is fitted inside the outer tube so as to be movable in the axial direction. Holes perpendicular to the axis are made in the upper and lower parts of the main body, and springs are inserted into the upper and lower holes, respectively, and balls that are pressed against the inner wall of the outer tube are attached to both ends of each spring. A circuit inspection needle characterized by the fact that it is also equipped with a circuit inspection needle.