Checker head

Details Checker head Checker head

2000-05-09

2003-05-13

Cuneo, Kamand (Department: 2829)

Electricity: measuring and testing

Fault detecting in electric circuits and of electric components

Of individual circuit component or element

C324S754090

Reexamination Certificate

active

06563332

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a checker head with a pin to be brought into electrical contact with an inspected object such as a printed circuit in order to inspect the characteristics. More in detail, the present invention relates to a checker head used with connecting to a circuit tester in order to conduct electricity between a circuit tester such as the DC circuit tester and a test pad established in an inspected object.
BACKGROUND ART
An example of conventional checker head is shown in FIG.
5
. The checker head
70
shown in
FIG. 5
is made of the large number of set of a first contact pin
81
, a second contact pin
82
, a spring
83
and a wired socket
84
being disposed linearly and inserted through six laminated Bakelite board
71
-
76
. Still, the first contact pin
81
has the nail shape, and its tip protrudes from the Bakelite board
71
of the front.
Of course, through holes for the first contact pin
81
and the like to pass through each Bakelite board
71
-
76
are established. And, the through hole of the Bakelite board
71
has a small diameter in comparison with the through hole of the Bakelite board
72
, so the projection of the first contact pin
81
would be controlled by the contact of the ring division of the first contact pin
81
at this level difference.
The spring
83
is disposed in compressed condition, and pushes the second contact pin
82
toward an upward direction in FIG.
5
and pushes the wired socket
84
toward a downward direction in FIG.
5
. This push pressure makes electrical connection between the wired socket
84
and the first contact pin
81
. Especially, when the tip of the first contact pin
81
is pressed to a test pad
98
of a printed circuit
96
which is an inspected object, the spring
83
is further compressed. The push pressure increases as the compression of the spring
83
increases, and thus the electrical connection becomes more certain.
Still, the wired socket
84
has a structure in which a wire division
84
b
is tightened in a cylindric socket division
84
a
and connected to a circuit tester.
However, this conventional checker head
70
is not applicable to the recent printed circuit whose size has been reduced. Since the sizes of the recent printed circuits have been reduced, there have been demands that sizes and intervals of test pads
98
are smaller. In order to respond to theses demands, the pitch (it is shown by “p” in
FIG. 5
) of the first contact pin of the checker head must be decreased.
However, the limitation to reduce the pitch p was 0.6 mm in the checker head
70
shown in
FIG. 5
, since the wired socket
84
is used. The wired socket
84
has the above-mentioned structure in which a wire
84
b
is tightened in the cylindric socket
84
a
. In order to reduce the pitch p, it is necessary to decrease the diameter of the socket. But, it becomes more difficult to introduce and fix the wire
84
b
in the cylindric socket
84
a
as the socket diameter decreases. After all, the socket with a large diameter has been used because it is easy to introduce and fix the wire
84
b
in the cylindric socket
84
a.
One means for solving the problems has been disclosed by Unexamined Japanese Patent Application Publication No. Hei. 6-148236 (corresponding to U.S. Pat. No. 5,410,260). In this publication, an invention in which elimination of a wired socket may reduce the pitch of pins has been disclosed. The composition of the invention is a checker head comprising a middle insulator having a support hole that supports a large diameter division of a pin in the shaft line direction and receives a coiled spring, and being united in a
DISCLOSURE OF THE INVENTION
To solve the problems, the first invention is a checker head comprising a pin to be brought into contact with a test pad of an inspected object, a leading wire being connected to a circuit tester, a spring being linearly provided between the pin and leading wire to contact both of the pin and leading wire, and a laminated body through which the pin, leading wire, and spring pass. And, the composition that the spring is always compressed can be added in this checker head.
This first invention's specific example will be able to express as following. In a checker head comprising a front board having a hole, an electroconductive pin in which the tip division protrudes from the hole of the front board and is in contact with an inspected object, a checker head comprising a large diameter division which is disposed at the position in the rear from the front board and in contact with the marginal of the hole of the front board from the back surface side, a rear board which locates in the rear from the large diameter division and through which a leading wire passes, an electroconductive spring which is located between the large diameter division and the rear board, and the pin and the leading wire being electrically conducted through the spring in at least the condition that the pin is pushed to the rear board.
In this checker head, the large diameter division of the pin is located between the front board and the rear board. Moreover, the preceding end of the large diameter division is in contact with the marginal of the hole of the front board from the back surface side. Therefore, it is prevented that the pin is pulled out to front side of the front board. And, the spring is disposed between the large diameter division of the pin and the rear board, so the pin is pushed back by the elastic force when the pin is in contact with an inspected object and is pushed in. By this, the tip division of the pin and the inspected object surely contact and electrically conduct. And, the pin and the leading wire also contact through a spring each other and are electrically connected. In this case, the spring and the leading wire may be integratedly molded or may be united by joining different member together by welding or soldering, etc.
In addition, the specific example of the first invention can be added the structures in which a middle board is established between the front board and the rear board and has a large hole in comparison with the diameter of the large diameter division and the spring, and the large diameter division and the spring are located in the hole of the middle board. In this checker head, the spring and the large diameter division of the pin are together located in the hole of the middle board, so the hole positions the direction of the spring and the large diameter division in the plate surface of the front board and the like and their actuations are sure.
To solve the problems, the second invention is a checker head comprising a pin to be brought into contact with a test pad of an inspected object, a middle pin being in contact with the pin, a leading wire being in contact with the middle pin and being connected to a circuit tester, and the pin, middle pin, and leading wire being linearly disposed and passing through a laminated body including an elastic layer, and the elastic layer restricting their positions.
In addition, to solve the problems, the third invention is a checker head comprising a pin to be brought into contact with a test pad of an inspected object, a leading wire being in contact with the pin and connected to a circuit tester, and the pin and leading wire being linearly disposed and passing through a laminated body including an elastic layer, the elastic layer restricting their positions.
These second and the third invention's specific example can be expressed as in a checker head comprising a front board having a hole, an electroconductive pin of which a tip division protrudes from the hole of the front board and is in contact with an inspected object, a checker head comprising a large diameter division being disposed in the rear position from the front board in the pin and being in contact with the marginal of the hole of the front board from the back surface side, and an elastic layer retaining the pin with adherence to the position in the rear from front edge of the large diameter division of the pin.
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