JPH0635185Y2 - Through-hole resistance measuring device probe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a probe of a resistance measuring device for a through hole for measuring the resistance of a through hole portion of a wiring board coated with plating.

<Prior Art> As an easy and simple method for knowing the plating thickness of the through-hole plated portion and the plating quality, there is a resistance measuring method for measuring the voltage drop of the through-hole portion and detecting the resistance thereof.

In this resistance measuring method, since the voltage drop is very small, an optimal method for precisely measuring this is to arrange a probe having a detection end having a current supply contact and a voltage detection contact up and down. The four-terminal method is used in which the contact points of (1) are brought into contact with the upper and lower peripheral edges of the through hole portion.

As a resistance measuring device for carrying out such a method, there is one disclosed in JP-A-59-222771 or JP-A-60-154168.

This one has a basic structure in which probes are arranged above and below a through hole portion of a printed wiring board so that their detecting ends face each other so that they can come into contact with each other. , The detection ends of the lower probe are brought into contact with the lower peripheral edge, respectively, current is passed from the current supply contacts of the upper and lower detection ends, and the voltage between the voltage detection contacts is measured to calculate the resistance of the through-hole plating, The plating thickness is detected.

<Problems to be Solved by the Invention> By the way, a conventional probe is configured by integrating a probe head having a detection end and a head holder thereof. For this reason, the detection end of the probe head comes into contact with the peripheral edge of the through-hole portion, and a current is passed through the probe head, so that the wear is severe. It was

It is an object of the present invention to provide a probe having a structure in which a head holder and a probe head can be separated from each other, and further, a required electric connection can be surely made in a connected state.

<Means for Solving Problems> The present invention relates to a conductive rod which is connected to a rear part of a detection end having a current supply contact and a voltage detection contact, and which is electrically connected to the voltage detection contact on the rear surface. A probe head having an end formed therein, a holding hole into which a mounting rod portion of the probe head is inserted,
An insulating pipe is inserted vertically into the insertion hole, and a spring receiving surface for receiving a ridge in the guide cylinder is externally provided, and is electrically connected to a current supply contact of the probe head. A head holder and a contact rod that is inserted into the insertion hole of the head holder through an insulating pipe and has its tip elastically contacted with the conductive end of the probe head by a ridge and the rear part protruding outward of the head holder. It is characterized by being configured.

<Operation> To connect the head holder and the probe head,
In advance, insert an insulating pipe into the insertion hole in the head holder, and further attach the spring and the contact rod,
The mounting rod portion of the probe head is inserted into the holding hole of the head holder while pressing the contact rod at the end of the mounting rod portion against the spring, and is fixed by appropriate means such as bolting.
By such fixing, the head holder contacts the probe head at the periphery of the holding hole or its fixing portion and is electrically connected to the current supply contact, and the contact rod is elastically connected to the detection end of the probe head by the biasing force of the spring. In contact, electrical connection with the voltage detection contact is secured.

<Embodiment> An embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a resistance measuring device to which the probes 28a and 28b of the present invention are applied.

Here, at the rear portion of the case-shaped lower frame 1, an upper frame 2 which is arranged substantially parallel to the lower frame 1 and forms a mounting gap 3 with the lower frame 1 is held.

Further, on the lower frame 1, a loading table 4 having an operation hole 5 formed in a front portion is fixedly arranged.

Further, in the mounting gap 3, a mounting plate 6 having a leaf spring 6a attached to the base end is arranged on the lower surface of the upper frame 2, and the base end thereof is fixed to a bolt 7
Is supported by. A tension spring 9 is hooked on the mounting plate 6 and a spring hooking piece 8 in the upper frame 2, and the mounting plate 6 is suspended around a bolt 7 at an upper inclined position. At the front end of the mounting plate 6 on the operation hole 5, the upper probe 28a
A guide tube body 29a for holding the probe is held, and the detection end 53 of the probe 28a is projected downward.

Further, on the upper surface of the upper frame 2, an elevating handle 10 for inserting the elevating rod 12 is held by a guide holding member 13 fixed on the upper frame 2.

The upper end of the lifting rod 12 is connected to the movable end of a power switch 11 for current supply fixed to the base frame of the lifting handle 10.
By contracting and moving with respect to the switch 11, the switch 11 is closed and a spring attached to the inside of the switch 11 holds the elevating rod 12 at the protruding position.

A detection switch 14 is mounted on the mounting plate 6 at a position directly below the lifting rod 12, and the detection roll 14 is mounted on the mounting plate 6.
The lower end of the lifting rod 12 is received by 15 and supports the load of the lifting handle 10. The contact 16 opened and closed by the detection roll 15 is urged to project by an internal spring, and the urging force can support the load of the elevating handle 10, and the descent of the elevating handle 10 described later It can also oppose the restoring elasticity of the mounting plate 6. On the other hand, this spring is made weaker than the spring incorporated in the power switch 11 described above, and as a result, the lifting handle to be described later is provided.
When the lowering operation of 10 causes the power switch 11 to be closed at the end, the probe head 35 of the probes 28a and 28b is closed.
When the current is supplied after the detection end 53 of the contact hole is surely contacted with the peripheral edge of the through hole portion and the pressing of the lifting handle is released, the open / close switch is first opened to detect the probe from the upper and lower peripheral edges z, z of the through hole portion y Before dissociation of 28a, 28b,
The current supply is stopped so that the detection end 53 is prevented from being damaged by the spark.

The lower surface of the mounting plate 6 is brought into contact with the upper surface of a wiring board x, which will be described later, to make the mounting plate 6 incapable of tilting downward, and a lifting handle.
A stopper 17 is provided which applies a downward pressing force of 10 to the detection roll 15.

At the lower part of the loading table 4, a mounting plate 20 provided with a leaf spring 20a along the loading table 4 is provided, and a rear end of the mounting plate 20 is provided with a bolt 21
And is swingably disposed. The leaf spring 20a is attached to the mounting plate 20 for the same reason as the mounting plate 6 described above. At the tip of the mounting plate 20, a guide cylinder 29b containing a lower probe 28b is held at a position directly below the guide cylinder 29a via the operation hole 5, and the detection end 53 of the probe 28b is projected upward. ing.

Further, an actuator 22 composed of a solenoid is arranged below the mounting plate 20, and its rod end is brought into contact with the lower surface of the mounting plate 20. The actuator 22 is driven by closing the detection switch 14, raises the rod, and tilts the mounting plate 20 upward about the bolt 21.

In addition, a display device 25 is provided at the front end of the upper frame 2.

The probe 28a, 28b and the guide cylinders 29a, 29b have a second configuration.
4 will be described.

The guide cylinders 29a, 29b are covered with a cover cylinder 31 on a base ring 30 fixed to the mounting plate 6 or the mounting plate 20 to generate guide paths for the probes 28a, 28b therein. Also,
At the inner lower end of the base ring 30, a reduced diameter hole 32 is formed for allowing the probe head 35 to project outward.

The probes 28a and 28b are formed by connecting a head holder 34 and a probe head 35.

As shown in FIGS. 2 and 3, the head holder 34 includes a collar piece 36 that is in contact with the inner surface of the peripheral wall of the mouth hole 32 and has an upper surface thereof as a spring receiving surface, and the mouth that is continuous to the contact side. A fitting insertion portion 37 having substantially the same diameter as the hole 32, a taper portion that further reduces the diameter from the fitting insertion portion 37 to the tip side, and a screw hole 38a extending from the reduced diameter end and extending in the radial direction are formed. The fixing part 38 is connected to the outer peripheral part, and the mounting rod part 48 of the probe head 35 is provided inside thereof.
A large-diameter holding hole 39 into which is inserted and an insertion hole 40 into which the insulating pipe 41 is inserted are slightly eccentric and are connected in the vertical direction.

The insulating pipe 41 inserted into the insertion hole 40 has a spring receiving portion 42 formed in the upper part of the mounting hole therein, and the contact rod 43 is inserted into the insulating pipe 41. The contact rod
43 is provided with an arcuate contact end in the lower part, and the central part is reduced in diameter to form a spring receiving edge at the lower reduced end, and the spring receiving edge and the spring receiving part of the insulating pipe 41 described above. A spring 45 is attached between 42 to urge the contact rod 43 downward and to project the upper portion from the insulating pipe 41 to enable the electrical connection.

Next, the configuration of the probe head 35 will be described with reference to FIGS.

Reference numeral 47 is a root material of an arrow made of a conductive material, the rear portion of which is a small-diameter mounting rod portion 48, one side surface of the mounting rod portion 48 is shaved to form a flat surface portion 49, which is screwed from the screw hole 38a. The tip of the tightening screw 61 is adapted to be in pressure contact.

As shown in FIG. 5, the arrow root base material 47 is formed with a through hole at a position that is eccentric so that the circumference of the arrow root base material 47 does not overlap with the center of the base material 47. Is coated in an insulative coating on the periphery and is inserted in a close-fitting manner, and the rear end of the conductive rod 50 is projected from the rear end of the base material 47 to make it a conductive end.

Further, the front end portion of the base material 47 is positioned so that the tip of the cone is located at the center, and the two smooth cone surfaces 51, 51 and one partial cone surface 52 are equiangularly spaced, and the inclination angle is different. It is ground to about 45 degrees, and the ridgeline between the smooth conical surfaces 51, 51 is the conductive rod 50.
It crosses the front edge of. At this time, the conductive rod 50 is
Since it is in the eccentric position as described above, the apex tip is not located in the conductive rod 50.

With this configuration, the conductive rod 5 between the smooth conical surfaces 51, 51
A ridgeline of 0 serves as a voltage detection contact 54, and a detection end 53 having the partial conical surface 52 as a current supply contact 55 is formed. The voltage detection contact 54 of the probe head 35 and the current supply contact 55 are electrically insulated by an insulating coating applied around the conductive rod 50, and in the circumferential direction by the smooth conical surfaces 51, 51. It is physically discontinuous.

The detection end 53 has a narrow width surface portion along the conical direction from the tip of a conical electrode as disclosed in JP-A-59-97397 as a voltage detection contact, and the other surface portion as a current supply contact to insulate each other. There are various other types such as a conical electrode formed by the above, and any of them may be used.

In this probe head 35, the attachment rod portion 48 is inserted into the holding hole 39, and the tip of the tightening screw 57 screwed from the screw hole 38a is attached to the flat surface portion 4.
The head holder 34 is brought into contact with the head holder 34 and is connected to the head holder 34. In this connected state, the arrow-shaped base material 47 that constitutes the voltage detection contact 54
The mounting rod portion 48 of is electrically connected to the head holder 34. In addition, a conductive rod protruding from the rear end of the probe head 35
The conducting end of 50 abuts on the tip of the contact rod 43 and elastically contacts the tip of the contact rod 43 by the urging force of the spring 45. Therefore, the contact rod 43 is connected to the voltage detection contact 54 at the tip of the conductive rod 50.

In the configuration of the probes 28a and 28b, the head holder 3
4. The probe head 35 can be easily separated and connected by advancing and retracting the tightening screw 57, and in the connected state, the voltage detection contact is made by the spring 45.
The connection between 54 and the contact rod 43 can be reliably achieved. Therefore, when the detection end 53 of the probe head 35 is worn out, only the probe head 35 needs to be replaced.

The probes 28a and 28b having such a configuration are guide cylinders 29a and 29b.
In the inside, by the spring 56 attached between the spring receiving piece fixed to the cover tube 31 and the flange piece 36 of the head holder 34, the flange piece is provided.
The probe head 35 is projected from the mouth 32 by holding the mouth 36 at a position where it abuts the peripheral wall of the mouth 32.

It should be noted that the head holder 34 is restrained in a non-rotatable manner with respect to the mouth hole 32 while being movable in the vertical direction.

Such rotation restraint is, for example, that the mouth hole 32 has a rectangular shape, the fitting insertion portion 37 has a rectangular shape following this, or a vertical groove is formed on the flange piece 36, and the groove is formed on the inner surface of the base ring 30. Various configurations may be proposed for forming the guide protrusion for insertion into the.

The voltage detection contacts 5 of the detection ends 53, 53 of the probes 28a, 28b.
A resistance detector 58 is connected to 4,54 from the protruding end of the contact rod 43 as shown in FIG. 6, and a DC constant current source 59 is connected to the current supply contacts 55, 55 from the rear surface of the head holder 34. It is connected via a power switch 11.

The operation of the above embodiment will be described.

The wiring board x is inserted onto the table 4 from the front, and the through hole portion y is visually positioned directly below the detection end 53 of the upper surface probe 28a. At this time, since the detection end 53 of the lower surface probe head 35b is located below the upper surface of the mounting table 4, the mounting table 4 of the wiring board x is mounted.
Can be mounted on the lower surface probe head 35b without damaging the detection end 53.

After roughly positioning the through-hole portion y as described above, the elevating handle 10 is pushed down, the mounting plate 6 is tilted downward against the tension spring 9, and the probe 28a and the stopper 17 are lightly attached to the upper surface of the wiring board x. It descends to the contact position.

In this state, the probe is attached to the through hole portion y of the wiring board x.
Since the detection end 53 of 28a is in slight contact, the wiring board x is slightly moved to the optimum position.

Then, the lifting handle 10 is further pressed. By this pressing operation, the mounting plate 6 cannot be lowered because the stopper 17 abuts on the upper surface of the wiring board x, so that the lifting rod 12 of the lifting handle 10 lowers the detection roll 15 and the detection switch 14 Causes closure. Therefore, the actuator 22 is driven, and the rod is extended to cause the mounting plate to move.
20 tilts upward, the lower probe 28b at the front end thereof rises, and the detection end 53 of the probe head 35b comes into contact with the peripheral edge z of the through hole portion y from the operation hole 5.

When the elevating handle 10 is pressed from this contact position, the power switch 11 in the elevating hole handle 10 is closed as described above, and a current flows between the current supply contacts 55, 55. Then, in this way, by passing an electric current after the contact,
53 Spark damage is prevented.

When the probes 28a, 28b are in contact with the upper and lower peripheral edges z of the through hole portion y, the probes 28a, 28b are
It floats up against 656, and the fitting insertion part 37 escapes from the mouth hole 32. Therefore, the inclined surface of the tapered portion 38a enables the probes 28a and 28b to be slightly inclined, and the detection end 5
It becomes possible for 3,53 to follow the upper and lower peripheral edges z, z of the through hole portion y in a uniform manner.

Thus, as described above, the current of the DC constant current source 59 flows from the current supply contacts 55, 55, the voltage drop is detected by the voltage detection contacts 54, 54, and the value is read by the resistance detector 58 to be calculated. Then, the resistance value is calculated and displayed on the display device 25.

<Effect of Device> As described above, the device of the present invention comprises the probes 28a and 28b which are composed of the separable head holder 34 and the probe head 35, and the contact rod 43 protruding outward is connected to the voltage detecting contact in the connected state. Since the conductive end connected to 54 is elastically contacted by the spring 45 to secure the electrical connection, the wear of the detection end 53 does not occur without disturbing the electrical connection of the probes 28a and 28b. Therefore, only the probe head 35 can be exchanged, which is extremely economical.

[Brief description of drawings]

The attached drawings show an embodiment of the present invention. Fig. 1 is a vertical sectional side view of a measuring device, Fig. 2 is an enlarged vertical sectional side view of a main part, and Fig. 3 is a mounting of a probe head 35 to a head holder 34. FIG. 4 is a vertical sectional side view, and FIG. 4 is a side view of the probe head 35.
FIG. 5 is a front view of the detection end 53 of the probe head 35, and FIG. 6 is a circuit diagram showing current control of the probes 28a and 28b. 28a, 28b; probe, 34; head holder, 35; probe head, 36; flange piece, 39; holding hole, 40; insertion hole, 41; insulating pipe, 42; spring receiving portion, 43; contact rod, 45; Bar, 47; arrow-shaped base material, 48; mounting rod part, 50; conductive rod, 53; detection end, 54; voltage detection contact, 55; current supply contact, x; wiring board, y; through hole part, z; peripheral edge

Claims (1)

[Scope of utility model registration request] 1. A probe head comprising a detection rod having a current supply contact and a voltage detection contact, and a mounting rod portion connected to a rear portion of the detection end, and a conductive end electrically connected to the voltage detection contact formed on a rear surface thereof. A holding hole into which the attachment rod of the probe head is inserted,
An insulating pipe is inserted vertically into the insertion hole, and a spring receiving surface for receiving a ridge in the guide cylinder is externally provided, and is electrically connected to a current supply contact of the probe head. A head holder and a contact rod that is inserted into the insertion hole of the head holder through an insulating pipe and has its tip elastically contacted with the conductive end of the probe head by a ridge and the rear part protruding outward of the head holder. A probe of a resistance measuring device for a through hole, which is configured.