U.S. patent application number 09/891801 was filed with the patent office on 2002-01-10 for socket for removably mounting an electronic part.
Invention is credited to Ikeya, Kiyokazu.
Application Number | 20020004329 09/891801 |
Document ID | / |
Family ID | 18703175 |
Filed Date | 2002-01-10 |
United States Patent
Application |
20020004329 |
Kind Code |
A1 |
Ikeya, Kiyokazu |
January 10, 2002 |
Socket for removably mounting an electronic part
Abstract
A socket (2) for removably mounting a BGA package. A plurality
of contacts (7) are mounted in a base (4), the contacts each having
a pair of arms (7a and 7b) for effecting compressive electrical
contact of the solder balls of the BGA package being held. A slider
(5) is slidably mounted on the base (4) for opening and closing of
the arms. An external force is applied in a prescribed direction at
a cam follower portion (52) of the slider by a cam member (20)
provided on a diagonal line of a generally square base (4). The cam
engages the cam follower portion (52) of the slider at a selected
angle of inclination and is movable in a direction which crosses,
at a right angle, the moving direction of the slider.
Inventors: |
Ikeya, Kiyokazu; (Sunto-gun,
JP) |
Correspondence
Address: |
Russell E. Baumann
Texas Instruments Incorporated
MS 20-21
34 Forest St.
Attleboro
MA
02703
US
|
Family ID: |
18703175 |
Appl. No.: |
09/891801 |
Filed: |
June 26, 2001 |
Current U.S.
Class: |
439/259 |
Current CPC
Class: |
H05K 7/1007 20130101;
H01R 13/193 20130101 |
Class at
Publication: |
439/259 |
International
Class: |
H01R 013/15 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 7, 2000 |
JP |
2000-206219 |
Claims
What is claimed:
1. Socket apparatus comprising a base having a top surface and
having an outer peripheral wall portion formed with a bore through
the top surface and extending generally vertically relative to the
top surface, a plurality of contact members mounted in the base in
a selected arrangement, the contact members each having a pair of
contact arms which are relatively movable between open and closed
positions, a slider having an electronic part seating surface and
having an engagement portion for engaging the contact members for
moving the contact arms, the slider being slidably disposed on the
top surface of the base and having an outer peripheral wall portion
formed with a cam follower surface, a cam member having an
elongated body of a selected length with a longitudinal axis and
having an outer end, the body slidingly received in the bore of the
base for generally vertical movement relative to the top surface of
the base, a first spring member mounted in the base for urging the
slider in a first contact closing direction, a second spring member
mounted in the base for urging the cam member in a direction
upwardly out of the bore, the cam member having a cam surface
extending longitudinally along at least a portion of the length of
the body, the cam follower surface being biased into engagement
with the cam surface by the first spring member, the cam member
having a force receiving surface at the outer end of the cam member
whereby a force applied to the force receiving surface which
depresses the cam member causes the cam surface to slide against
the cam follower surface and move the slider and engagement portion
in a second contact opening direction opposite to the first contact
closing direction.
2. Socket apparatus according claim 1 in which the cam surface is
curved relative to the longitudinal axis.
3. Socket apparatus according to claim 1 in which the bore has a
longitudinal axis and the cam follower surface is curved relative
to the longitudinal axis of the bore.
4. Socket apparatus according to claim 2 in which the bore has a
longitudinal axis and the cam follower surface is curved relative
to the longitudinal axis of the bore when the slider is mounted on
the base.
5. Socket apparatus according claim 4 in which the cam follower
surface has a greater degree of curvature than degree of curvature
of the cam surface.
6. Socket apparatus according to claim 1 in which the body of the
cam member is formed with a plurality of depressions in the cam
surface to mitigate frictional resistance.
7. Socket apparatus according to claim 1 in which the bore in the
base has a closed end and the length of the body of the cam member
is selected so that the closed end serves as a stop for the cam
member to provide a fixed position of the slider when the cam
member engages the stop.
8. Socket apparatus according to claim 1 in which the cam member is
formed with a head having a flat force receiving surface which
extends laterally beyond the body of the cam.
9. Socket apparatus according to claim 8 in which the area of the
force receiving surface of the head is between approximately
{fraction (1/10)} to {fraction (1/20)} of the area of the top
surface of the base.
10. Socket apparatus according to claim 1 in which the base and the
slider are generally square in top plan view having an imaginary
diagonal line and the first spring member applies a force to the
slider which is in a direction in parallel with the diagonal line
and the first contact closing direction and the second contact
closing direction are in parallel with the diagonal line.
11. Socket apparatus according to claim 1 in which the base and the
slider are generally rectangular in top plan view having an
imaginary diagonal line and the contact arms are relatively movable
in a direction parallel with the diagonal line and the first spring
member and the cam member are located along the diagonal line.
12. Socket apparatus according to claim 1 further comprising an
electronic part holding mechanism movable toward and away from the
base to load an electronic part on the seating surface, the
electronic part holding mechanism having a force applying member
aligned with and movable into engagement with the force receiving
surface of the cam member.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to electrical property and
burn-in tests for electronic parts, such as integrated circuits,
and more particularly to a socket for providing an electrical
connection between each terminal of an electronic part and an
external device for removably loading the electronic part in the
socket so that the leads of the socket are electrically connected
to the respective terminals of the electronic part.
BACKGROUND OF THE INVENTION
[0002] Generally, electronic parts such as IC packages, in which IC
chips have been sealed with plastic, are subjected to a reliability
test called an electric property test or a burn-in test prior to
their shipment in order to distinguish between acceptable and
unacceptable products.
[0003] In electric property tests, input and output characteristics
of the IC chips, pulse properties, noise leeway, and the like are
tested. In burn-in tests, on the other hand, IC packages that have
passed the electric property test are arranged in an oven and are
made to function at an elevated temperature, 125.degree.
centigrade, for instance, and under a source voltage which is
approximately 20% higher than the rated value. Those IC packages
which fail in the burn-in test are removed as being unacceptable
and only those others which continue functioning properly are
shipped out as acceptable products.
[0004] In recent years, BGA (Ball Grid Array) packages having
terminals made of solder balls positioned on the lower side of the
package in a selected matrix, e.g., a zigzag fashion, have become
popular as a desirable surface-loading type IC package. A BGA
package provides advantages including features in which the
terminals can be widely set while maintaining small outer
dimensions and that the terminals are sturdy and resistant to
deformation when they are brought into contact with other
parts.
BACKGROUND OF THE INVENTION
[0005] FIGS. 6(a) and 6(b) show a conventional socket for loading a
BGA package for a burn-in test. Socket 101 has a square-shaped base
102 and a slider 103 for loading BGA package 100 is arranged for
movement in a horizontal direction on the base. A cover 104, having
an opening 104a therein, is received at the top of base 102. Cover
104 is vertically movable relative to base 102 by means of
compression coil springs 105. A through hole is formed in slider
103 and base 102 corresponding to each solder ball 100a of the BGA
package. A respective contact 106 for electrical connection with
each solder ball 100a of the BGA package is arranged to extend
through the through holes of base 102 and slider 103. Each contact
106 is made of an elongated metallic member with a pair of arms
106a and 106b facing upward. A protuberant part, not shown in the
drawing, is provided on one arm of arms 106a and 106b (e.g., arm
106a) and, as this protuberant part engages the partition wall of
slider 103, arms 106a and 106b are adapted to open and close upon
sliding motion of the slider. A sliding mechanism for moving slider
103 in a direction which is in parallel with the bottom wall of
base 102 is provided on opposite sides of the slider. The sliding
mechanism includes a generally L-shaped lever member 108 rotatably
mounted on each end of a shaft 107 provided at one side of base 102
(the right side in the drawings) and the short arm 108a of lever
member 108 is rotatably linked to shaft 109 disposed in a
vertically extending slot in slider 103 and which extends in
parallel relation with shaft 107. A lever member 111 is rotatably
mounted on each end of shaft 110 provided at the opposite side of
base 102 and the tip of lever member 108 is slidingly attached by a
pin 112 in a slot formed in each respective lever member 111
intermediate to its opposite ends. When cover 104 is not pressed,
tip 111 a of each lever member 111 is adapted to touch the
protuberant part 104b of cover 104. Compression coil springs 113
are located in the vicinity of shaft 110 for biasing the slider
toward the right as seen in the drawings.
[0006] In a socket made as described above, when cover 104 is
pressed down from the state shown in FIG. 6(a) to the state shown
in FIG. 6(b), lever members 108 and 111 rotate toward base 102 and
shaft 109 transfers motion to slider 103 in conformity with the
movement of lever member 108, thereby causing the slider to shift
in the X-direction. As a result, arm 106a of the arms of each
contact 106 starts opening due to engagement with the partition
wall of slider 103. If, in this state, BGA package 100 is inserted
through the central opening 104a of cover 104, BGA package 100 is
positioned by guide 103c so that each solder ball 100a enters
between arms 106a and 106b of a respective contact 106.
[0007] When the downward force on cover 104 is removed, lever
members 108 and 111 rise and slider 103 is returned in the X+
direction by the force of coil springs 113 and the stored force of
the contact arms, with a result that arms 106a and 106b of each
contact 106 are closed and each solder ball 100a of BGA package 100
is held by arms 106a and 106b of a respective contact 106. Thus,
each solder ball 100a of BGA package 100 is electrically connected
to a respective contact 106.
[0008] With respect to a conventional socket 101 as described
above, the linkage mechanism comprising the lever members 108 and
111, pin 112 and shafts 107, 109 and 110 is used to move slider
103. However, the number of parts involved is considerable and the
construction becomes complicated, thereby requiring a number of
assembly steps with concomitant assembly time before completion.
Further, the use of the linkage mechanism adds to the size and
weight of socket 101 making it larger and heavier than desired.
[0009] In copending applications, U.S. Ser. Nos. 09/694,636 and
09/850,622 filed respectively on Oct. 23, 2000 and May 7, 2001 and
assigned to the assignee of the present invention, prior art
linkage mechanisms of the type described are obviated by directly
pressing the slider of the main socket body by means of a force
applying member provided on a jig for loading the electronic part
to be tested. The force applying member has a surface inclined at a
selected angle and the force applying member of the jig is moved
vertically toward and away from the socket, thereby making it
possible for the slider of the main socket body to move in a
direction normal to the movement of the force applying member,
i.e., horizontal versus vertical directions.
[0010] In view of the fact that the amount of movement of the
slider is therefore dependent upon the inclined angle of the force
applying member of the jig that employs such a mechanism, there is
a problem in that the degree of opening of the arms of the contact
varies from one jig to another. Much of this depends on the
precision with which the parts of the jig are made, with a result
that the amount of opening of the contact arms cannot be controlled
by the structure of the socket body alone.
SUMMARY OF THE INVENTION
[0011] An object of the present invention is to provide an
apparatus which overcomes the above noted limitations of the prior
art. Another object of the invention is the provision of a socket
in which the amount of opening of the arm-like contact part of the
contact member can be predetermined at a certain value by means of
the socket itself without depending upon the accuracy of the
various parts of the jig.
[0012] A socket made in accordance with the invention comprises a
main socket body for removably receiving an electronic part in
which the terminals of the electronic part are arranged according
to a selected pattern. A plurality of contact members are arranged
in the main socket body in conformity with the terminal pattern of
the electronic part. Each contact member has a pair of contact
arms, capable of elastically opening and closing to effect
compressive electrical engagement with a respective connective
terminal of the electronic part. A contact opening and closing
member has an engagement part adapted for engagement with the
contact members to move the contact arms in the opening and closing
direction by receiving an external force that is approximately in
parallel with the opening and closing direction of the contact arms
applied at a cam follower portion of the contact opening and
closing member. A force transfer cam member, provided at a selected
location on the edge portion of the main socket body, has a cam
surface that engages the cam follower portion of the contact
opening and closing member at a selected angle and which is movable
in a direction which crosses, at approximately a right angle, the
moving direction of the contact opening and closing member so as to
cam the cam follower portion, while sliding there against.
According to a feature of the invention, the cam member is mounted
on the main socket body, with the contact arms of each contact
member being opened by the action of the cam member. This
arrangement provides the ability to control the accuracy of the cam
follower portion of the contact opening and closing member and the
position of the cam member within the socket without depending upon
the accuracy of the parts of the separately provided jig so that
the amount of the opening of the contact arms of each contact
member can be determined more consistently. According to another
feature of the invention, the cam member is formed as a button type
member having a head of a size suitable to enable one to press the
cam member with a finger, for example, so that one can press down
the cam member with one hand in connection with unloading the
electronic part from the socket. Thus, the operability of a manual
unloading operation can be improved by locating the cam member on
the edge portion of the main socket body so that the seating area
for the electronic part can be more fully exposed to further
improve the operability of the unloading operation. According to
yet another feature of the invention, the main socket body can be
formed in a rectangular configuration, such as in the shape of a
square, with the contact opening and closing member being arranged
so that the engagement of the contact opening and closing member
moves the arms of the contact members in a direction which is in
parallel with the imaginary diagonal line of the main socket body.
The contact opening and closing member itself can be guided in the
diagonal direction and in the preferred embodiment, the cam member
is arranged at one corner on the diagonal line of the main socket
body.
[0013] Accordingly, a single cam member is sufficient to move the
contact opening and closing member. As a consequence of this, the
number of parts whose accuracy has to be controlled is reduced,
thereby making it possible to better control the amount of opening
of the contact arms of each contact member.
[0014] According to a feature of the invention, a plurality of
depressions or longitudinal grooves of a selected size can be
formed in the cam surface of the cam member to reduce the surface
area of the cam member which engages the cam follower portion of
the contact opening and closing member. Accordingly, it becomes
possible to reduce the frictional resistance when the cam member
slides over the cam follower portion of the contact opening and
closing member.
[0015] According to another feature, an electronic part holding
mechanism is provided which is movable while maintaining a state
facing the main socket body of the socket in order to load an
electronic part. The holding mechanism is part of a contact opening
and closing jig that has a force applying part that is engageable
with the cam member of the socket. Thus, it is only necessary to
provide one force applying location on the contact opening and
closing jig for effecting movement of the contact opening and
closing member by means of the cam member. Accordingly, it becomes
possible to reduce the size of the contact opening and closing jig
itself and the number of parts of the contact opening and closing
jig.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Other objects, advantages and details of the novel and
improved socket of the invention appear in the following detailed
description of preferred embodiments of the invention, the detailed
description referring to the drawings in which:
[0017] FIG. 1 is a side elevational view showing a simplified
structure of an electronic part loading system 1 comprising a
contact opening and closing jig 3 and a socket 2 made according to
a preferred embodiment of the invention along with an electronic
part 10;
[0018] FIG. 2(a) is a top plan view showing a simplified structure
of the socket according to the FIG. 1 embodiment;
[0019] FIG. 2(b) is an enlarged portion of FIG. 2(a) designated by
a dashed line P in FIG. 2(a);
[0020] FIG. 3 is a cross sectional view taken on the diagonal line
L in FIG. 2(a);
[0021] FIG. 4(a) is an enlarged, broken away portion of FIG. 3;
[0022] FIG. 4(b) is a further enlarged portion of FIG. 4(a)
designated by a dashed line Q in FIG. 4(a);
[0023] FIG. 5 is an enlarged cross sectional view of the force
receiving cam follower portion of the slide member and a modified
cam member; and
[0024] FIGS. 6(a) and 6(b) are cross sectional views showing a
socket for burn-in tests made according to the prior art.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0025] As shown in FIG. 1, electronic part loading system 1 made
according to a preferred embodiment of the invention is for loading
a BGA package (electronic part) 10 on which solder balls
(connective terminals) 10a are arranged according to a selected
pattern. Loading system 1 comprises a socket 2 for removably
mounting the BGA package and a combination electronic part delivery
mechanism and contact opening and closing jig (contact opening and
closing jig) 3 which is arranged facing the socket.
[0026] With particular reference to FIG. 2(a), socket 2 comprises a
base (main socket body) 4 and a slider (contact opening and closing
member) 5 received on the base. The socket and slider are made
using suitable resinous material such as polyether imide, etc. Base
4 is adapted for mounting on a wired substrate such as a printed
substrate not shown in the drawing. The base is preferably formed
in a rectangular configuration, such as a square, for example. As
shown in FIG. 3, a stopper 6 is provided at the bottom of the base
at the center thereof. A large number of spaced apart
longitudinally extending members 7 are arranged at a prescribed
height in a direction which is perpendicular to the top and bottom
surfaces of base 4 and are fixed by stopper 6 in order to prevent
the contact members from slipping toward the bottom side of the
base. Contact members 7 are arranged in conformity with the pattern
of solder balls 10a of the BGA package 10 to be tested.
[0027] As shown in FIG. 2(b) or FIG. 4, a pair of elastically
movable arms (contact arms) 7a and 7b are provided at the upper
portion or tip of each contact member 7. According to this
embodiment, arms 7a and 7b of each contact member are arranged
facing each other in a direction which is in parallel with the
diagonal line L of base 4. As shown in FIG. 2(a), slider 5 is
formed generally in the shape of but smaller in size than the base.
Slider 5 is arranged for movement on base 4 in a direction
(indicated either by arrow head A or B) which also is in parallel
with diagonal line L of base 4.
[0028] A seating portion 50 is provided on the upper surface of
slider 5 for receiving BGA package 10. A positioning guiding part
51 is located around seating portion 50 for guiding and positioning
the BGA package on the seating portion. A large number of IC ball
accommodating holes 5b are arranged on seating portion 50 on the
upper surface of slider 5 in conformity with the pattern of contact
members 7. As shown in FIGS. 4(a) and 4(b), an engagement part 5a
of the slider is respectively provided in each IC ball
accommodating hole 5b. These engagement parts 5a have a guiding
surface 5a1 formed in such a way as to incline toward its opposite
side as one moves in a downward direction as shown in the drawing.
Each of the aforesaid contact members 7 is arranged in a respective
IC ball accommodating hole 5b with arms 7a, 7b received on opposite
sides of engagement part 5a in hole portions 5b1 and 5b2,
respectively. One arm 7b of the pair of arms 7a and 7b of each
contact member is arranged to move in a direction (indicated by an
arrow head A) which is away from arm 7a by the camming action of
guide surface 5a1 of engagement part 5a of slider 5 in conformity
with the movement of slider 5 in the direction indicated by the
arrow head, thereby making it possible for the pair of arms 7a and
7b of each contact member 7 to open at a distance which is somewhat
larger than the outer shape of the solder balls 10a of BGA package
10.
[0029] A first compression coil spring 8 is mounted at one corner
of base 4 on diagonal line L providing a spring bias on slider 5
toward the side of the other corner on diagonal line L as shown in
FIGS. 2 or 3.
[0030] A cam member 20 in the shape of a button is provided at the
corner of base 4 diametrically opposite to spring 8. As shown in
FIG. 4(a), cam member 20 has a head 20a at one end of an elongated
body 20b having a longitudinal axis F. The upper surface of head
20a is flat while body 20b has a selected length extending in a
direction that crosses the upper surface, at a right angle. Cam
member 20 may be conveniently formed with resin similar to the
resin used for slider 5, for instance. Preferably, resin for the
cam contains glass fiber as a reinforcing agent and further
contains a component for reducing friction such as
polytetrafluorethylene. The area of the top surface of head portion
20a of cam member 20 is selected to be in the range of
approximately {fraction (1/10)} through {fraction (1/20)} of the
area of base 4. A guide hole 41 having a longitudinal axis E is
formed in base 4 for slidably receiving body 20b of cam member 20.
Guide hole 41 is formed to a depth which is somewhat less than the
length of body 20b of cam member 20 in a direction (indicated
either by arrow head C or arrow head D) which crosses, at a right
angle, the moving direction of slider 5. Cam member 20 is
preferably arranged so that the cam member can bottom out to ensure
a predictable position of body 20b when the cam member is actuated.
That is, bottom 41a of bore 40 serves as a stop surface for cam 20.
The cam member is biased upwardly by the spring force of a second
compression coil spring 21 received inside an open ended bore
through bottom 20b1 of body 20b and seated in the bottom 41a of
guide hole 41.
[0031] Slider 5 is formed with a force receiving or cam follower
portion 52 at the corner and on the outer periphery of the side of
the slider that faces cam member 20 for receiving the external
force from cam member 20 in connection with opening and closing of
arms 7a and 7b of contact member 7 as shown in FIG. 4(a). This cam
follower portion 52 is formed having a curved surface facing the
cam member in the shape of a convex configuration with a selected
curvature, as shown in FIG. 4(a). Cam surface 20b2 is formed on the
side surface of body 20b extending along the longitudinal axis of
body 20b over at least a portion of its length and facing cam
follower portion 52 of slider 5. Cam surface 20b2 is also formed
having a curved surface in the shape of a convex configuration with
a more gradual curvature (i.e., larger radius) than the curvature
of cam follower portion 52 of slider 5 forming an angle
therebetween which is suitable for slider 5 to move as a cam
mechanism. Cam follower portion 52 of slider 5 maintains a state of
being in linear engagement with cam surface 20b2 of the cam member
20 by means of the spring force of first compression coil spring 8
described above.
[0032] As shown in FIG. 1, contact opening and closing jig 3 has a
head 31 moveable in the vertical direction shown by arrow head C or
D, while maintaining a state facing base 4 of socket 2. An
electronic part holding mechanism 32, mounted on head 31, is
capable of adhering and holding BGA package 10 by air suction. At a
selected location on head 31, further, a force applying member 33,
which is adapted to engage head 20a of cam member 20 on the socket,
extends downwardly from that part which applies suction to BGA
package 10. An engagement surface 33a, which may be flat as shown,
is formed on lower surface of force applying member 33.
[0033] In the embodiment described above, if contact opening and
closing jig 3 is lowered in the direction indicated by arrow head
D, the force applying member 33 of contact opening and closing jig
3 engages and depresses head 20a of cam member 20 until cam member
20 bottoms out against the surface 41a of guide hole or bore 41 of
base 4. Guide bore 41 is preferably formed so that its longitudinal
axis E extends in a direction generally normal to the top surface
of the base on which the slider moves. The cam follower portion 52
of slider 5 receives the external force from force applying member
33 through cam member 20 which includes a component in the
direction which is indicated by arrow head A as the cam surface
20b2 of cam member 20 slides along the curved surface of cam
follower portion 52 of slider 5, as shown in FIG. 3. In this
connection, wearing of cam follower portion 52 of slider 5 and cam
member 20 is minimized due to the linear engagement between the two
parts. Thus, slider 5 moves in the direction indicated by arrow
head A for a fixed distance in response to the fixed stroke of cam
member 20 and the engagement part 5a engages with arm 7b of each
contact member, thereby opening up contact arms 7a and 7b.
[0034] BGA package 10 is placed on seating part 50 of slider 5 in
the open contact arms state. The contact opening and closing jig 3
is then raised by the force of spring 21 in the direction indicated
by arrow head C allowing cam member 20 to slide upwardly, thereby
causing an action to take place which is opposite to that which has
been described above. As a result, contact arms 7a and 7b of each
contact member 7 are closed. Because of this, each solder ball 10a
of the BGA package is compressively contacted by respective arms 7a
and 7b of a contact member.
[0035] In the present embodiment as described, cam member 20 for
moving slider 5 is provided on socket 2 and contact arms 7a and 7b
of each contact member 7 are caused to open up by the action of the
cam member. As a result, it becomes easier to control the
positional accuracy of force receiving part 52 of slider 5 and cam
member 20 within socket 2 without being dependent upon the accuracy
of the parts of contact opening and closing jig 3. Accordingly, it
becomes possible to set the amount of opening of contact arms 7a
and 7b of each contact member 7 at a selected fixed distance.
According to the above described embodiment, contact arms 7a and 7b
are caused to open in a direction which is in parallel with
diagonal line L along with the movement of slider 5 in a direction
of the diagonal line L of base 4 and the cam member 20 is arranged
at one corner on the diagonal line, thereby making it possible to
provide only one cam member 20 for moving slider 5. Due to a
decreased number of parts whose accuracy has to be controlled, it
becomes possible to better control the amount of opening of the
contact arms 7a and 7b of each contact member 7. By forming cam
member 20 in the shape of a button, it becomes possible to employ
one hand to press down cam member 20 in connection with unloading
BGA package 10 from socket 2. As a result, there is an advantage in
that the operability of such an unloading operation is improved.
Moreover, the operability of the above-described unloading
operation can be further improved as the exposure of seating
portion 50 is optimized due to the location of cam member 20.
Further, it is only necessary to provide force transfer member 33
for actuation of cam member 20 at one location on contact opening
and closing jig 3 when using a single cam member 20 on socket 2. As
a result, it becomes possible to reduce the weight and size of
contact opening and closing jig 3 itself and further reduce the
number of the parts thereof.
[0036] This invention is not to be restricted to the embodiment
described above but can be modified in various ways, For example,
the receiving part 52 of slider 5 and the cam follower portion 52
of slider 5 and the cam surface 20b of cam member 20 have curved
surfaces for the purpose of reducing wear due to frictional
resistance. If desired, as shown in FIG. 5, for instance, a
plurality of depressions 20b3 of a selected size may be provided on
cam surface 20b of cam member 20 so that the area of cam surface
20b2 that contacts cam follower portion 52 of slider 5 can be
further reduced, thereby making it possible to further reduce the
frictional resistance and wear of cam surface 20b2 of cam member 20
and cam follower portion 52 of slider 5.
[0037] In the above-described preferred embodiment, a resin
containing glass fiber is used as the material of cam member 20. It
is within the purview of the invention, however, to use a metal,
for instance, in these materials. In such a case, if a lubricating
layer (not shown in the drawing) is formed on cam surface 20b2 of
cam member 20 to a selected thickness by using molybdenum disulfide
or graphite, or the like, a greater effect can be achieved from the
standpoint of reducing the friction resistance or wearing.
[0038] In the above-described embodiment, a cam mechanism is
employed as a mechanism for converting vertical movement of cam
member 20 to horizontal movement of slider 5. However, the
invention is not restricted to this; for example, a linkage
mechanism, etc., can also be used. From the standpoint of reducing
the number of parts involved, however, it can be said that the cam
mechanism shown and described is more advantageous.
[0039] It will be understood that the invention can be used not
only for sockets for a burn-in test but also for sockets for an
electrical property test. It can further be used not only for BGA
packages but also for other packages such as PGA packages, and the
like.
[0040] In the above-described embodiment, cam member 20 is arranged
at a corner on the diagonal line L of base 4 in conformity with the
movement of slider 5 in parallel with diagonal line L of base 4.
However, it will be understood that slider 5 can be moved in
parallel with one side of base 4 and a single cam member or a
plurality of cam members can be arranged on the side which crosses,
at a right angle, said one side of base 4.
[0041] Further, in the above-described embodiment, force applying
member 33 is fixed to head 31 of contact opening and closing jig 3
and so that cam member 20 of socket 2 can be depressed along with
movement of contact opening and closing jig 3. However, it is also
possible to provide the force applying member so that it is
separately moveable up and down on head 31 of the jig.
[0042] According to the invention which has been described above, a
socket capable of bringing the amount of the opening of the contact
arms to a preselected value can be obtained by using the socket
side alone without depending upon the accuracy of the parts of the
jig.
[0043] In view of the above, it will be seen that the several
objects of the invention are achieved and other advantageous
results are obtained.
[0044] As various other changes could be made in the above
constructions without departing from the scope of the invention, it
is intended that all matter included in the above description or
shown in the accompanying drawings be interpreted as illustrative
and not in a limiting sense.
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