JPH0810233B2 - Contact probe - Google Patents

Description

The present invention relates to a contact probe for inspecting a printed circuit board (bare board, in-circuit, etc.) for inspecting a printed circuit board (bare board, in-circuit, etc.) for disconnection, short circuit, etc. .

"Prior art and its problems" A contact probe used for testing circuit continuity of a printed circuit board is fitted into a socket fixedly mounted on a mounting plate of a printed circuit board inspection machine as shown in FIG. And a plunger contact 3 mounted on the body 1 via a spring 2 and the like. A tip 4 of the plunger contact 3 is pressed against a surface 5 to be measured of a printed circuit board 7. The plunger contact 3 is configured to be movable relative to the body portion 1 when it is opened.

Then, when the tip portion 4 vertically contacts the surface 5 to be measured and the spring 2 is vertically pressed, there is no problem, but between the sliding portion 6 of the plunger contact and the body portion 1. Since there is a slight gap between the body part 1 and the plunger contact 3 when the tip end is in contact with the surface to be measured at an angle or when a non-uniform force is applied to the spring for some reason. The sliding portion 6 is separated from the sliding portion instantaneously, and as a result, the current stops flowing instantaneously, which is an obstacle to the continuity test. This is because when conducting a circuit continuity test or the like on a printed circuit board, a current must always flow normally through the probe contact itself. In particular, since the need for more precise tests has been increasing recently, there is a strong demand for probe contacts without such defects.

In order to eliminate such a drawback, the applicant has formed a notch portion which gives a spring property to the rear end of the plunger contact, and the spring property allows the plunger contact and the body part to slide while elastically contacting each other. The invention was developed and a patent application was previously filed (Japanese Patent Laid-Open No. 62-58170).

On the other hand, recently, very densely arranged printed circuit boards have been developed, and as a result, finer plunger contacts for inspecting the printed circuit boards are being demanded. Although the above-mentioned drawback is solved by the plunger contact forming the above-mentioned cutout portion, there is a limit to making it finer, and there is a problem that it cannot be applied to an extra-fine type plunger contact.

The present invention is intended to solve such conventional problems all at once, and to provide a contact probe which enhances the contact between the plunger contact and the body portion and can be made into an extremely thin type. To aim.

[Means for Solving Problems] In order to achieve the above object, in the present invention, a contact probe slidably mounted on a body sleeve via a spring, and an inner peripheral surface of the sleeve tip. And a slit formed downward from the sleeve tip end, and a retractable coil spring ring fixed to the outer peripheral surface of the sleeve tip.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the plunger contact 13 is
It is slidably mounted in the body sleeve 11 via a spring 12. An inwardly projecting portion 17 is formed at the upper end of the body sleeve 11, and a spring ring 18 is fitted in an outer peripheral recess facing the protruding portion 17. As shown in FIG. 2, at the upper end of the body sleeve 11, there are formed two or four slits 19 facing downward from the upper end. Therefore, the sliding portion 16 of the plunger contact and the body sleeve 11 are elastically contacted by the protruding portion 17,
Since the projecting portion 17 is configured to freely expand and contract, the plunger contact 13 and the projecting portion 17 of the body sleeve are always in close contact with each other.

In the above embodiment, the protrusion 17 is a continuous ridge, and the inner diameter thereof is the plunger outer diameter dimension, but this is not necessarily the case. Further, the outer peripheral recessed portion corresponding to the protruding portion may be a recessed portion that does not move the spring ring 18.

The width of the slit 19 is preferably about 0.05 to 0.2 mm, and the length thereof is preferably about 3 to 8 times the sleeve outer shape.

In this way, the body 11 having the plunger contact 14 mounted therein is fitted into the socket 22. Socket 22
It is welded or adhered through a mounting plate called a test head of a printed circuit board inspection machine.

"Operation" Next, the operation of the present invention configured as described above will be described.

First, the tip end portion 20 of the plunger contact is brought into contact with the solder surface 15 of the printed board 21. At this time, the sliding part 16
Even when a strong lateral force is applied to the sliding portion 16, the sliding portion 16 and the body portion 11 are slidably elastically abutted by the elastic force of the spring ring 18, so that the sliding portion 16 and the body portion 11 are There is no fear of leaving. Therefore, a stable current always flows through the probe contact.

[Advantages of the Invention] As described above, according to the present invention, the protrusion formed on the inner peripheral surface of the body sleeve and the contact probe sliding portion are brought into close contact with each other by the force of the spring-like ring. Since the body and the sleeve are elastically abutted and therefore do not normally separate from each other, a stable current always flows through the probe contact, and the contact probe is of an ultra-fine type that was impossible with conventional contact probes of this type. be able to. Specifically, with the conventional contact probe, it was impossible to reduce the outer diameter to 1.3 mm or less, but according to the present invention, it is possible to use a contact probe with an extremely fine diameter of about 0.3 mm, and the reliability is also high. improves.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a perspective view showing a body sleeve of the present invention, and FIG. 3 is a sectional view showing a conventional contact probe. In the figure, 11 ... Body sleeve, 17 ... Projection, 18 ... Spring ring, 19 ... Slit.

Claims (1)

[Claims] 1. A contact probe slidably mounted on a body sleeve via a spring, a protrusion formed on the inner peripheral surface of the sleeve tip, and a slit formed downward from the sleeve tip. And a contractible spring-like ring fixed to the outer peripheral surface of the tip of the sleeve.