JPH0743688U - In-circuit test probe - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To prevent the contact head from contact failure by forcibly removing the paste, dust, etc. adhering to it without wearing or deforming the contact head. Provide a probe for in-circuit test that can be performed. [Structure] A probe body 1, a plunger 2, and a compression spring 3 are provided. The probe body 1 is made of an elongated cylinder body and has a constricted portion 1a.
An upper end is open and a lower end is a closed bottom 1b. The plunger 2 has a contact head 2a at the upper end.
The probe body 1 is inserted from the opening at the upper end of the probe body 1 and is attached so as to be slidable in the axial direction. The plunger 2 has a middle detail 2b in the middle thereof and can be inserted through the constricted portion 1a of the probe body 1. A bulging locking portion 2c is formed at the tip of the inner detail 2b and is locked by the constricted portion 1a so that the plunger 2 does not come out of the probe body 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an in-circuit test probe.

[0002]

[Prior art]

 Generally, for a printed circuit board (hereinafter referred to as mounting printed circuit board) on which parts such as ICs and resistance elements are mounted, it is inspected whether each mounted part functions properly or whether correct circuit connection is made. For this purpose, for example, as shown in FIG. 3, a matrix board B in which a large number of probes P are implanted and a mounting printed board K are brought close to each other, and the contact head h at the tip of the probe P is mounted on the mounting printed board. The test point t on the back surface of K is pressed and contacted, and a short-circuit test or component inspection, for example, is performed by an appropriate inspection device (not shown) via the connection w at the lower end of the receiving tube R into which the probe P is inserted. Is going.

As shown in FIG. 4, the probe P is mainly inserted into a cylindrical probe main body 1 with a closed bottom and a tip end portion so as to reciprocate in the axial direction in the probe main body 1. A plunger 2 having a contact head 2a inside and a probe body 1 housed in the probe body 1 and elastically pushed out of the probe body 1 to press the contact head 2a against a test point of a mounted printed circuit board. It is composed of a compression spring 3 for tightening. Therefore, the contact between the contact head 2a and the test point is elastic by the compression spring 3.

By the way, the test point t is generally connected by brazing, but since flux is used during the brazing, this flux remains attached to the surface of the test point t. Not only that, but dust and dirt are also attached.

Therefore, when the contact head 2a is brought into pressure contact with the test point t, there is a problem that a residue of the above-mentioned flux or dust adheres to the contact head h to cause a contact failure, and a test error is likely to occur.

In order to solve such a problem, conventionally, a method has been adopted in which the probe is slightly rotated during the pressure contact so as to scratch the test point t and ensure contact. However, this method has a problem in that the test point t may only be destroyed, and the tip of the contact head of the probe may be worn or deformed.

[0007]

[Problems to be solved by the device]

 The present invention was made in order to solve the above-mentioned conventional problems, and the purpose thereof is to forcibly remove basalt, dust, etc. adhering to the contact head without causing wear or deformation of the contact head. The object is to provide an in-circuit test probe that can be removed to eliminate poor contact with the test point.

[0008]

[Means for Solving the Problems]

 The in-circuit test probe of the present invention comprises a cylindrical probe main body with a closed bottom, and a plunger having a contact head at the tip, which is inserted so as to reciprocate in the axial direction in the probe main body. , An in-circuit test probe comprising a compression spring housed in the probe body, which elastically pushes the plunger out of the probe body to press its contact head into contact with a test point on a printed circuit board. It is characterized in that a vent hole is bored in the plunger in the axial direction and an air outlet is opened in the contact surface of the contact head.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross section of a probe, which is mainly composed of a probe body 1, a plunger 2, and a compression spring 3.

The probe body 1 is composed of an elongated cylindrical body, has a constricted portion 1a formed in the middle thereof, an upper end portion is open, and a lower end portion is a closed bottom portion 1b. The probe body 1 is fitted and attached to, for example, a receiving cylinder R fixed to the matrix board B.

The plunger 2 has a contact head 2a at the upper end. There are various shapes of the tip end surface of the contact head 2a depending on the shape of the test point t and the intended contact mode. FIG. 2 shows an example thereof.

The plunger 2 is inserted from the opening at the upper end of the probe body 1 and is attached so as to be slidable in the axial direction. The plunger 2 has a middle detail 2b in the middle thereof so that it can be inserted through the constricted portion 1a of the probe body 1. A bulging diameter locking portion 2c is formed at the tip of the inner detail 2b and is locked by the constricted portion 1a so that the plunger 2 does not come out of the probe body 1.

A vent hole 2d is formed in the inside of the plunger 2 in the axial direction thereof, and is open at the upper and lower ends of the plunger 2. The opening at the upper end is an air outlet 2d 'which is opened at the front end surface of the contact head 2a.

The compression spring 3 is set between the bottom portion 1b of the probe body 1 and the engaging portion 2c at the lower end portion of the plunger 2, and the plunger 2 is elastically pushed out from the probe body 1. I am trying.

Since the probe of this embodiment is configured as described above, when the matrix head and the mounting printed circuit board are brought close to each other and the contact head 2a is pushed down, the plunger 2 is shown in FIG. 1 (A). As shown in FIG. 1B from the state, the probe body 1 is pushed against the compression spring 3.

When the plunger 2 is pushed in, the air inside the probe body 1 in which the compression spring 3 is housed blows out from the air outlet 2d ′ of the contact head 2a through the vent hole 2d. By this air blowing action, the flux, dust, etc. adhering to the surface of the contact head 2a are blown off and cleaned.

[0017]

[Effect of device]

 A cylindrical probe main body having a closed bottom, a plunger having a contact head at the tip, which is fitted and inserted so as to reciprocate in the axial direction in the probe main body, and housed in the probe main body. An in-circuit test probe consisting of a compression spring that elastically pushes the plunger out of the probe body and presses the contact head into the test point of the mounting printed circuit board. Since a vent hole was drilled in the contact head to open the air outlet on the contact surface of the contact head, the paste, dust, etc. adhering to it can be forcibly removed without wearing or deforming the contact head. Therefore, it is possible to eliminate poor contact with the test point.

[Brief description of drawings]

FIG. 1 is a sectional view (A) showing an embodiment of a probe of the present invention, and a sectional view (B) showing a state where a plunger is pushed in.

FIG. 2 is a perspective view showing an example of a contact head.

FIG. 3 is a main part explanatory view showing an inspection state by a probe.

FIG. 4 is a partial cross-sectional view showing a conventional probe.

[Explanation of symbols]

 1 probe body 1a constricted part 1b bottom part 2 plunger 2a contact head 2b inside details 2c locking part 2d vent hole 2d 'air outlet B matrix board h contact head K mounted printed circuit board P plunger R receptacle t test point w wire

Claims (1)

[Scope of utility model registration request] 1. A cylindrical probe main body having a closed bottom, a plunger having a contact head at its tip, which is fitted and inserted so as to reciprocate in the axial direction in the probe main body, and housed in the probe main body. In the in-circuit test probe including a compression spring that elastically pushes the plunger out of the probe body and presses the contact head into a test point of the mounting printed circuit board, the probe is axially passed through the plunger. An in-circuit test probe, characterized in that pores are formed to open an air outlet on the contact surface of the contact head.