IC socket

In an IC socket, a depressing portion of a cover is pressed against a pressure receiving portion of a pressure receiving lever by downwardly pressing the cover, and then a contact portion of a contact is displaced in the rearward direction by movement of the pressure receiving lever. The depressing portion is formed by an inclined cam surface having a downward gradient in the rearward direction. When the cover is moved in the downward direction, the pressure receiving portion is caused to slidably move from the upper end side to the lower end side of the downwardly inclined cam surface.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an IC socket adapted to release a contact 
from engagement with an IC package by displacing a contact portion of the 
contact in the rearward direction when a cover is actuated in the downward 
direction. 
2. Description of the Prior Art 
To facilitate understanding of the present invention, a conventional IC 
socket having the foregoing type disclosed in an official gazette of U.S. 
Pat. No. 5,009,609 will briefly be described below. As shown in FIG. 11 
and FIG. 12, a cover 4 disposed to be displaced in the upward/downward 
direction on a socket body 1 is provided as means for displacing a contact 
in the rearward direction. 
The cover 4 includes a downwardly projecting depressing portion 4a and an 
inclined cam surface 4a' having an upward gradient and extending rearward 
of a contact 3. When the cover 4 is actuated in the downward direction, 
the inclined cam surface 4a' serves to depress an end of a pressure 
receiving lever 6 extending rearward of the contact 3. As the end of the 
pressure receiving lever 6 is slidably displaced from the lower end side 
to the upper end side, a contact portion 3a of the contact 3 is displaced 
in the rearward direction. 
Thus, the contact 3 is released from the contacted state relative to a lead 
5a of an IC package 5 accommodated in an IC accommodating portion 2. At 
this time, the IC package 5 can be inserted in and removed from an IC 
socket. 
When the actuating force of the cover 4 is released, the contact 3 is 
restored to an original state by its own resilient force. At this time, 
the cover 4 is raised up by a pressure receiving portion 6a adapted to 
slidably move from the upper end side to the lower end side so that the 
contact portion 3a is brought in pressure contact on the upper surface of 
the lead 5a. 
Since the IC socket is constructed such that the contact portion 3a of the 
contact 3 is brought into pressure contact with the upper surface of the 
lead 5a, the lower surface of the lead to be soldered in practical use of 
the IC package will not be damaged. In addition, since a robot arm can be 
easily used for actuating the cover 4 and a group of contacts 3 can be 
displaced with a reduced magnitude of force in the rearward direction, the 
IC socket is often used as an IC package measuring socket or the like. 
In spite of the aforementioned advantages, since the IC socket is 
constructed such that an inclined cam surface 4a' is formed to have an 
upward and rearward gradient, and a pressure receiving portion 6a slidably 
moves in such a manner as to escape in the direction opposite to the 
direction of lowering of the cover 4 as well as the direction of 
depressing of the pressure receiving portion 6a, it is obvious that a 
quantity of depressing of the pressure receiving portion 6a is reduced 
compared with a quantity of lowering of the contact opening/closing cover 
4. Therefore, to assure that the contact portion 3a of the contact 3 is 
sufficiently displaced in the rearward direction to the position where it 
does not interfere with the IC package 5, it is necessary to lower cover 4 
to such a degree as to compensate for the aforementioned quantity of 
reduction. This leads to a problem that the quantity of lowering of the 
cover 4 is increased. 
When the quantity of lowering of the contact opening/closing cover 4 is 
increased in that way, there arises a problem that the IC socket must be 
constructed with an increased height. In addition, when a stroke of 
displacement of the cover 4 is elongated, there is a possibility that the 
cover 4 will be actuated less in the downward direction. Thus, there 
arises another problem that the quantity of displacement of the contact is 
hardly maintained. 
SUMMARY OF THE INVENTION 
The present invention has been made in consideration of the aforementioned 
problems. 
An object of the present invention is to provide an IC socket which reduces 
the quantity of lowering of a cover necessary to adequately displace a 
contact, and moreover, to ensure that a contact portion of the contact can 
be displaced by a required distance in the rearward direction. 
Another object of the present invention is to provide an IC socket which is 
dimensioned to have a reduced height. 
To accomplish the above objects, the present invention provides an IC 
socket including a plurality of contacts arranged in parallel to a socket 
body to come in contact with leads of an IC package, a cover disposed on 
the socket body so as to be displaced in the upward and downward 
directions, and a pressure receiving lever associated with downward 
displacement of the contact to cause rearward displacement of the contact 
wherein when the cover is actuated in the downward direction, a certain 
intensity of depressing force is imparted to a pressure receiving portion 
with a depressing portion disposed on the cover to induce rearward 
displacement of the cover, wherein a depressing portion for the cover is 
formed by an inclined cam surface having a downward gradient in the 
rearward direction. 
It is acceptable that the whole length or a part of the inclined cam 
surface is formed by a curved plane. 
In addition, it is also acceptable that the whole length or a part of the 
inclined cam surface is formed by a straight plane. 
Other objects, features and advantages of the present invention will 
readily become apparent from reading of the following description which 
has been made in conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will now be described in detail hereinafter with 
reference to the accompanying drawings which illustrate preferred 
embodiments thereof. 
FIG. 1 to FIG. 5 show an IC socket constructed in accordance with a first 
embodiment of the present invention, FIG. 6 and FIG. 7 show an IC socket 
constructed in accordance with a second embodiment of the present 
invention, FIG. 8 and FIG. 9 show an IC socket constructed in accordance 
with a hird embodiment of the present invention, and FIG. 10 is a view 
which shows the operational state of a pressure receiving portion in 
cooperation with a downward inclined cam surface in each of the first to 
third embodiments of the present invention. 
In each embodiment, a socket body 1 molded of insulative synthetic resin 
includes a substantially rectangular IC accommodating portion 2 at its 
central part which is kept open in the upward direction so as to 
accommodate an IC package 5. A plurality of contacts 3 (merely a single 
contact is shown in most of the drawing figures for the convenience of 
illustration) are arranged in parallel to each other along two opposing 
sides or four sides of the IC accommodating portion 2 corresponding to a 
plurality of leads 5a of the IC package 2, and a cover 4 for imparting a 
force to displace the contacts 3 to a position in which they do not come 
in contact with the IC lead 5a during removal or insertion of the IC 
package (FIG. 4), or to a position in which the contacts are released from 
the contacted state with the IC leads 5a (FIG. 3). 
The cover 4 includes a window 4b corresponding to the IC accommodating 
portion 2 so that IC packages 5 can be fitted in the IC accommodating 
portion 2 through the window 4b. 
The IC accommodating portion 2 includes a rib 12 which extends in parallel 
to a row of contacts 3 and is located inwardly of the row of contacts 3. 
As shown in FIG. 2 and others, the rib 12 restrictively defines the 
position of the side surface of an IC package body 5b from which leads 5a 
protrude. The lower surfaces of the base ends of crab foot-like leads 5a 
bent with two steps are placed on the upper surface of the rib 12, whereby 
an IC package body 5b is supported with its bottom surface spaced above 
the bottom surface of the IC accommodating portion 2. 
Each contact 3 includes a support plate portion 3b supported on an upper 
surface of a contact receiving portion 1a of the socket body 1, and a 
press fitting portion 3c projecting downward of the support plate portion 
3b. The press fitting portion 3c is press-fitted into a contact 
press-fitting hole 11 so as to allow the contact 3 to stand upright. 
Further, a terminal portion 3d is projected downward of the press fitting 
portion 3c. 
In addition, each contact 3 includes a curved spring portion 3e which 
extends from the upper part of the support plate portion 3b in a forward 
(i.e. inward) direction (i.e. toward the IC accommodating portion 2), and 
moreover, it includes contact portion 3a which projects slantwise 
forwardly (i.e. inwardly) toward a lead support surface 10. 
In the drawings, reference numeral 6 denotes a pressure receiving lever 
which causes the contact portion 3a of the contact 3 to be displaced in 
the rearward (i.e. outward direction upon downward displacement of the 
cover 4. Referring to FIG. 1 to FIG. 5, the pressure receiving lever 6 is 
prepared separately from the contact 3 and is molded of an insulative 
synthetic resin. 
Each of the pressure receiving levers 6 extends in parallel with its 
respective row of contacts and includes a number of through slits 6b 
through which a number of contacts 3 are respectively inserted. The 
contact portion 3a of each of the the contacts 3 is projected outwardly 
from its respective through slit 6b (FIGS. 2 and 3). 
Each through slit 6b opens in both the downward direction and the upward 
direction, and the side-to-side position of the contact 3 inserted through 
each the slit 6b is restrictively defined by the separated walls 6b' 
forming the slits 6b. The pressure receiving lever 6 also includes an 
abutment portion 6c which engages the contacts 3, and causes displacement 
of the contacts 3 in the forward or rearward direction as the lever 6 is 
turned. 
Namely, the upper end of the curved spring portion 3e of each contact 3 is 
inserted through the respective through slit 6a formed between the 
separated walls 6b', a contact portion 3a is projected forward of the 
upper opening of the through slit 6b, and an inverted L-shaped portion of 
the contact portion 3a located at the head portion of the latter 
resiliently rests on the lead 5a. 
Each of the pressure receiving levers 6 includes shaft portions 6d on the 
opposite side thereof, and the separated walls 6b' and slits 6b are 
arranged in parallel to each other in the direction perpendicular to the 
axis line of the shaft portions 6d. Thus, the pressure receiving lever 6 
is rotatably supported on the socket body 1 with the aid of the shaft 
portions 6d which are located below the cover 4. 
Each of the pressure receiving levers 6 includes a pressure receiving 
portion 6a by way of which the separated walls 6b' are connected to each 
other in the spaced relationship. The pressure receiving portion 6a faces 
a depressing portion 4a of the cover 4, such that the depressing portion 
4a is supported by the pressure receiving portion 6a. Thus, the cover 4 is 
supported by the pressure receiving levers 6. 
As shown in FIG. 2, an inclined cam surface 4a' is formed corresponding to 
the depressing surface of the depressing portion 4a and is inclined 
downwardly and rearwardly of the contact portion 3. 
A part or the whole downward inclined cam surface 4a' is composed of a 
curved plane. Otherwise, as shown in FIG. 1 to FIG. 4, the whole length of 
the downward inclined cam surface 4a' is composed of a curved plane. For 
example, the starting side (upper end side) of the curved plane may extend 
linearly with a small gradient and the tail end side (lower end side) of 
the same may extend linearly with a large gradient. For example, the 
curved plane portion having the small gradient may be a straight plane. 
While the downwardly inclined cam surface 4a' faces the pressure receiving 
portion 6a of the pressure receiving lever 6, the cover 4 is supported by 
the pressure receiving portion 6a. 
The cover 4 and the pressure receiving lever 6 are operatively associated 
with each other while they are brought in contact with each other. 
As shown in FIG. 2, the contact portion 3a of the contact 3 is normally 
biased in the forward direction by the resilient force of the spring 
portion 3e. When the IC package 5 is accommodated in the accommodating 
portion 2, the contact portion 3a comes in pressure contact with the upper 
surface of the IC lead 5a, but when no IC package 5 is present, the 
contact portion 3a comes in pressure contact with a lead supporting 
surface 10. The pressure receiving lever 6 is turned in the upward 
direction by allowing the spring portion 3e of the contact 2 to thrust 
against the abutment portion 6c, causing the cover 4 placed on the 
pressure receiving portion 6a to be raised up until the pressure receiving 
portion 6a comes in contact with the upper end portion of the downwardly 
inclined cam surface 4a'. 
When the cover 4 is lowered from the upper end waiting position as shown in 
FIG. 2, the pressure receiving portion 6a is slidably lowered by the 
downwardly inclined cam surface 4a', while the lever 6 is downwardly 
turned about the shafts 6d, as shown in FIG. 3. At this time, the abutment 
portion 6c trails the upper end of the spring portion 3e. As a result, the 
contact portion 3a starts to be slantwise upwardly displaced in the 
rearward direction against the spring portion 3e, causing the contact 
portion 3a to be released from contact with the IC lead 5a. 
When the cover 4 continues to be lowered, causing the pressure receiving 
lever 6 to be further turned in the downward direction, the pressure 
receiving portion 6a is slidably displaced to the lower end side (tail end 
side) of the downwardly inclined cam surface 4a' so that the contact 
portion 3a is displaced in the rearward direction while turning the 
pressure receiving lever 6 further in the downward direction as shown in 
FIG. 4. 
Consequently, while the contact portion 3a of the contact 3 is retracted 
outside of the range defined by the IC accommodating portion 2, the IC 
package 5 can be removed from or inserted into the IC accommodating 
portion 2. 
Next, the cover 4 is released from the lowering movement, and the 
associated components are displaced in the reverse direction from the 
state shown in FIG. 4 to the state shown in FIG. 2. Specifically, a 
depressing force is applied to the abutment portion 6c by the restorable 
force of the spring portion 3e of the contact 3, and the pressure 
receiving lever 6 is turned in the upward direction, causing the contact 
portion 3a of the contact 3 to be slantwise downwardly displaced in the 
forward direction. In this manner, the contact portion 3a is brought into 
pressure contact with the upper surface of the IC lead 5a. At this time, 
the pressure receiving portion 6a is slidably displaced along the surface 
of the downwardly inclined cam surface 4a' from the lower end side to the 
upper end side thereof, and the cover 4 is raised. 
In the embodiment as mentioned above, the total quantity of lowering of the 
cover is transmitted to the pressure receiving portion 6a, and moreover, 
the height difference between the upper end side of the downward inclined 
cam surface 4a' and the lower end side of the same is added to the 
foregoing quantity of lowering, resulting in the pressure receiving 
portion 6a being correspondingly thrusted. Therefore, the required 
quantity of lowering of the cover 4 can be minimized. 
According to the second embodiment of the present invention as shown in 
FIG. 6 and FIG. 7, a pressure receiving lever 16 molded of an insulative 
synthetic resin is prepared separately from a contact 13, and is turnably 
supported by a shaft 16d located behind the contact 13. On the other hand, 
a hook 13f is projected from an upper end portion of the contact 13 to the 
rear side so that the hook 13f is held in an engaged state in the vicinity 
of the pressure receiving lever 16. A pressure receiving portion 16a is 
formed at the rear end of the pressure receiving lever 16, and the 
pressure receiving portion 16a is brought into contact with a downwardly 
inclined cam surface 14a' of a depressing portion 14a of a cover 14, the 
cam surface 14a' being formed in opposing relationship to the pressure 
receiving portion 16a. Further, the pressure receiving portion 16a 
supports the cover 14. 
In the second embodiment, the downwardly inclined cam surface 14a' is 
formed with a straight surface. 
As shown in FIG. 6, when a contact portion 13a of the contact 13 is 
displaced in the forward direction in conformity with the resilient force 
of a spring portion 13e to move into pressure contact with a lead support 
surface 110 or into pressure contact with an upper surface of an IC lead 
5a, the hook 13f imparts a tensile force to the fore end of the pressure 
receiving lever 16, causing the pressure receiving portion 16a formed at 
the other end of the pressure receiving lever 16 to be turned in the 
upward direction with the shaft 16d as a center. 
As a result, the pressure receiving portion 16a raises the inclined cam 
surface 14a', and moreover, raises the cover 14. 
From the operative state as shown in FIG. 6, as the cover 14 is lowered 
from an upper limit waiting position, the pressure receiving portion 16a 
is lowered by the downwardly inclined cam surface 14a', causing the 
pressure receiving portion 16a to be slidably displaced from the upper end 
side to the lower end side. Subsequently, the pressure receiving lever 16 
is turned with the shaft 16d as a center so that the hook 13f is trailed 
by the pressure receiving lever 16. Consequently, the contact portion 13a 
is slantwise upwardly displaced in the rearward direction against the 
resilient force of the spring portion 13e, whereby the contact portion 13a 
is released from the contact state with the IC lead 5a. 
While the contact portion 13a of the contact 13 is retracted outside of the 
range defined by an IC accommodating portion 2, an IC package 5 can be 
removed from or inserted into the IC accommodating portion 2. 
Next, when the cover 14 is released from the lowered state, the associated 
components are displaced in reverse from the state shown in FIG. 7 to the 
state shown in FIG. 6. Specifically, a certain intensity of tensile force 
is imparted to the fore end of the lever 16 by the restorative force of 
the spring portion 13e of the contact 13, and the pressure receiving lever 
16 is turned in the upward direction. As the pressure receiving lever 16 
is turned in the upward direction, the contact portion 13a of the contact 
13 is slantwise downwardly displaced in the forward direction by the 
restoring force of the spring portion 13e of the contact 13, resulting in 
the contact portion 13a being brought into contact with the upper surface 
of the IC lead 5a. At this time, the pressure receiving portion 16a is 
slidably displaced from the lower end side to the upper end side of the 
downwardly inclined cam 14a', causing the cover 14 to be raised. 
In the second embodiment as described above, the whole quantity of lowering 
of the cover 14 is transmitted to the pressure receiving portion 16a, and 
the height difference between the upper end side of the downwardly 
inclined cam 14a' and the lower end side of the same is added to the 
foregoing quantity of lowering, resulting in the pressure receiving 
portion 16a being correspondingly depressed. Therefore, a quantity of 
lowering of the cover 14 can be minimized in the same manner as the first 
embodiment. 
In each of the first and second embodiments described above the pressure 
receiving lever 6 (or 16) and the contact 3 (or 13) are prepared as 
separate components. FIG. 8 and FIG. 9 show a third embodiment wherein a 
pressure receiving lever 26 and a contact 23 are integrally punched out. 
The contact 23 includes a cantilever extending in the rearward direction 
from a position located in the vicinity of the upper end, i.e, at a 
location at which the spring portion 23e and the contact portion 23a join, 
and the pressure receiving lever 26 is formed by the foregoing cantilever. 
The pressure receiving lever 26 includes a pressure receiving portion 26a 
which stands upright at a rear end thereof. This pressure receiving 
portion 26 comes in contact with a downwardly inclined cam surface 24a' of 
a depressing portion 24a of a cover 24, the cam surface 24a' being in an 
opposing relationship with the pressure receiving portion 26a, and the 
cover 24 is supported by the pressure receiving portion 26a. 
In this third embodiment, the downwardly inclined cam 24a' may be formed by 
a straight plane in the same manner as the second embodiment, or it may be 
formed by a curved plane in the same manner as the first embodiment, or it 
may be formed by a combination of a straight plane (i.e. a planar surface) 
and a curved plane (i.e. a curved surface). 
As shown in FIG. 8, a contact portion 23a of the contact 23 is displaced in 
the forward direction by the resilient force of the spring portion 23e of 
the contact 23 and comes in pressure contact with the upper surface of the 
IC lead 5a. However, when the contact portion 23a comes in pressure 
contact with the upper surface of the IC lead 5a, the pressure receiving 
lever 26 is turned in the upward direction. 
As a result, the pressure receiving portion 26a moves upwardly along a 
downwardly inclined cam surface 24a' and raises the cover 24. 
When the cover 24 is lowered from the upper limit waiting position from the 
operative state shown in FIG. 8, the pressure receiving portion 26a is 
pushed down by the downwardly inclined cam 24a' as shown in FIG. 9. Thus, 
the pressure receiving lever 26 is downwardly turned while the pressure 
receiving portion 26a is slidably displaced from the upper end side to the 
lower end side of the cam surface 24a'. Consequently, the contact portion 
23a is slantwise upwardly displaced in the rearward direction against the 
resilient force of the spring portion 23e whereby it is released from 
contact with the IC lead 5a. 
Thus, while the contact portion 23a of the contact 23 is located outside of 
the range of the IC accommodating portion 2, the IC package 5 is removed 
from or inserted into the IC accommodating portion 2. 
Next, when the lowering force imparted to the cover 24 is released, the 
associated components are displaced in reverse from the state shown in 
FIG. 9 to the state shown in FIG. 8. Specifically, the pressure receiving 
lever 26 is upwardly turned by the restoring force of the spring portion 
23e of the contact 23, and as the lever 26 is upwardly turned, the contact 
portion 23a of the contact 23 is slantwise downwardly displaced in the 
forward direction by the restoring force of the spring portion 23e, 
causing the contact portion 23a to be moved into pressure contact with the 
upper surface of the IC lead 5a. At this time, the pressure receiving 
portion 26a is slidably displaced along the downwardly inclined cam 
surface 24a' from the lower end side to the upper end side thereof so as 
to allow the cover 24 to be raised. 
According to the third embodiment as described above, the whole quantity of 
lowering of the cover 24 is transmitted to the pressure receiving portion 
26a, and the difference in height between the upper end side and the lower 
end side of the downwardly inclined cam surface 24a' is added to the 
quantity of lowering of the cover 24. Therefore, the quantity of lowering 
of the cover 24 can be minimized in the same manner as in each of the 
first embodiment and the second embodiment of the present invention. 
FIG. 10 shows the relationship between the quantity H2 of lowering of the 
pressure receiving portion 6a (or 16a or 26a) and the quantity H3 of 
displacement of the same in the rearward direction relative to the 
quantity H1 of lowering of the cover 4 (or 14 or 24) in each of the first 
to third embodiments of the present invention. 
As is apparent from FIG. 10, the quantity H2 of lowering of the pressure 
receiving member 6a can be increased relative to the quantity H1 of 
lowering of the cover 4 (i.e. the distance H2 is greater than the distance 
H1), and moreover, a quantity H3 of displacement of the pressure receiving 
portion 6a can be sufficiently maintained. 
This fact is directly reflected in the quantity of displacement of the 
contact portion 3a of the contact 3 in the rearward direction. 
As is apparent from the above description, a large quantity of displacement 
of the contact portion 3a in the rearward direction can be obtained with a 
small quantity of lowering of the cover 4 (i.e. the distance H3 is greater 
than the distance H1). 
While the present invention has been described above with respect to a few 
preferred embodiments thereof, it should of course be understood that the 
present invention should not be limited only to these embodiments but that 
various changes or modifications may be made without departure from the 
scope of the present invention as defined by the appended claims.