IC socket

Abstract: An IC socket comprises a socket board having an IC mount table. Contacting portions of tips of a plurality of contacts arranged in parallel relation on the socket board are inserted into a plurality of positioning holes which are arranged in parallel relation on a marginal portion of the IC mount table in order to contact with corresponding contacting pieces of an IC which is placed on the IC mount table. Dividing ridges are formed by lower ends of the partition walls on the entrance side for the contacts, which are formed between the adjacent positioning holes arranged in parallel relation.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an IC socket comprising a socket board provided with an IC mount table. 2. Brief Description of the Prior Art Japanese Patent Early Laid-open Publication No. Sho 63-291375 discloses an IC socket comprising a socket board provided with an IC mount table, the socket board being provided with a plurality of contacts arranged in parallel relation, contacting portions of the tips of the contacts being inserted into a plurality of positioning holes arranged likewise in parallel relation on the marginal portion of the IC mount table to contact with contacting pieces of an IC. In the above IC socket, the contacts implanted in the socket board are positioned in the neighbourhood of contacting points closest to the IC contacting pieces by the IC mount table so as to be correctly corresponded to the IC contacting pieces which are placed on the IC mount table. However, while the above IC socket has such an advantage as that the contacts and the IC contact pieces can be correctly corresponded each other, it has such a shortcoming as that when the IC mount table 2 is assembled to the group of contacts 1 arranged in parallel relation and at micro pitches on the socket board as shown in Fig. 11, much difficulty is encountered to correctly correspond the group of positioning holes 3 arranged likewise in parallel relation and at micro pitches on the IC mount table 2 to the group of contacts 1 and insert the former into the latter as one group. Therefore, much labour and time are required for assembly. Moreover, if a part of the contacts in the group of contacts 1 are one sided as illustrated, in addition to the above-mentioned difficulty to properly correspond and insert the positioning holes as one group, there arises another problem. That is, if the operator unfortunately fails to notice the existence of the one sided contacts 1 and tried hard to press the same into the IC mount table 2, the contacting portions of the tips of the contacts are bent and deformed by partition walls formed between the adjacent positioning holes 3. As a result, the IC socket including the IC mount table 2 becomes an inferior product. US-A-4,713,022 discloses a socket for flat pack electronic device packages comprising a lower section having a plurality of contacts and an upper section having slots therein for receiving the contacts. The slots are each tapered inwardly in both a longitudinal and a lateral direction within the upper section towards the upper surface thereof. SUMMARY OF THE INVENTION It is therefore a general object of the present invention to solve the above-mentioned problems and, in particular, to prevent contacts from being deformed when an IC socket mount table is assembled on a socket board. The invention provides an IC socket in accordance with Claim 1. As means thereof, a lower end of the entrance side of the partition wall formed between the adjacent positioning holes arranged in parallel relation as mentioned above is formed into a dividing ridge between the adjacent positioning holes, the above-mentioned one sided contact being portioned out by the dividing ridge so as to be guided into the corresponding positioning hole. According to the present invention, when the IC mount table is assembled to the group of contacts, the positioning holes arranged in parallel relation at micro pitches on the IC mount table are dilated by the dividing ridge, so that the positioning holes are properly corresponded to and inserted into the group of contacts with ease, and a quick assembly can be attained. If a part of the contacts among the group of contacts is one sided, the contacting portions of the tips of the contacts are slidingly portioned out with the inclined surfaces formed by the dividing ridges so as to be guided to the corresponding positioning holes. The above and other objects, advantages and features of the present invention will become more apparent as the description proceeds upon making reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a plan view of an IC socket showing one embodiment of the present invention; Fig. 2 is a sectional view taken on line A-A of Fig. 1; Fig. 3 is a plan view showing an example of parallel arrangement of the positioning holes and dividing ridges; Fig. 4 is a plan view showing another example of parallel arrangement of the positioning holes and the dividing ridges; Fig. 5 is a sectional view of the positioning holes showing the configurations of the dividing ridges; Fig. 6 is a sectional view of the positioning holes showing another example of the configurations of the dividing ridges; Fig. 7 is a sectional view of a socket with an IC loaded therein, wherein contacting portions of the tips of the contacts are already inserted into the positioning holes; Fig. 8 is a sectional view of a socket with an IC loaded therein, wherein the contacting portions of the tips of the contacts project from the positioning holes; Fig. 9 is a sectional view of a socket, wherein an IC is pressed by a presser cover so as to be contacted with the contacts; Figs. 10(A), 10(B) and 10(C) are sectional views for explaining the function of the dividing ridges when the IC mount table is assembled to the contacts; and Fig. 11 is a sectional view for explaining a state when the conventional IC mount table is assembled to the contacts. DETAILED DESCRIPTION OF THE EMBODIMENT The embodiment of the present invention will be described hereunder with reference to Figs. 1 through 10. The numeral 4 denotes a socket board formed of a square insulating board. The socket board 4 is provided in a central portion of its upper surface with an IC mount table 2 which can be moved upward and downward. The socket board 4 has a plurality of contacts 1 arranged in parallel relation along the outer four sides or two sides of the IC mount table 2. The IC mount table 2 is resiliently supported by, for example, a spring 5 disposed between the socket board 4 and the IC mount table 2. The IC mount table 2 is moved downward against the spring 5 and upward in accordance with the spring 5, and held in a predetermined raised position. The IC mount table 2 is provided with a plurality of positioning holes 3 arranged in parallel relation on the outer four sides or two sides. The positioning holes 3 are adapted to receive contacting portions of the tips of the contacts 1 for positioning. A corresponding number of positioning holes 3 to that of contacts are arranged in parallel relation at contact pitches and thus at the same pitches as the IC contact pieces 9a as illustrated in order to catch the individual contacts 1. On the other hand, the contacts 1 are implanted in the socket board 4 portion at the outer peripheral portion of the IC mount table 2. The contacts 1 have a resilient contacting piece la extending toward the IC mount table 2 from the implanted portion respectively, and the contacting portions 1b of the tips of the resilient contacting pieces 1a are inserted into the positioning holes 3 in the manner as mentioned above. The resilient contacting pieces 1a of the contacts 1 are restricted sideward displacement at the contacting portion 1b in the positioning holes 3. As a result, a relative position of the IC mount table and the contacts is established. At the same time, when the IC mount table 2 is moved forwardly and backwardly or righwardly or leftwardly in the horizontal direction by a micro-amount, the resilient contacting pieces la of the contacts are also displaced to maintain the relative position with the IC mount table 2. Each of the positioning holes 3 arranged in parallel relation has a partition wall 6 formed at a space between the adjacent positioning holes 3 and adapted to partition the positioning holes 3 individually. A lower end of each of the partition walls 6 forms a dividing ridge 7 between the adjacent positioning holes 3. The adjacent positioning holes 3 are connected through each dividing ridge 7, respectively. The dividing ridge 7 has a pair of downwardly inclined surfaces 7a and 7b formed on both sides thereof and for portioning out the adjacent contacts which are adjacent to each other with reference to the ridge line 7c of the dividridge 7 and guiding the contacts into the corresponding positioning holes 3. The positioning holes 3 are dilated on the entrance side of the contacts by the inclined surfaces 7a and 7b. Also, the edge of the partition hole 3 on the side adjacent to the partition wall 6 is formed in an inclined surface 8 enlarging downwardly and continuously connected with the downwardly inclined surfaces 7a and 7b formed on both sides of the dividing ridge 7. That is, the positioning holes 3 are dilated rightwardly and leftwardly at spaces between the adjacent positioning holes 3, and further dilated in the forward and backward direction by the inclined surfaces 8. As is shown in Figs. 3 or 4, the positioning holes 3 are formed in a rectangular shape, respectively. Furthermore, the positioning holes 3 are arranged to have a same phase and in parallel relation through the dividing ridges as shown in Fig. 3, or otherwise the positioning holes 3 are arranged to have a different phase and in a zigzag fashion likewise through the dividing ridges as shown in Fig. 4. The dividing ridges 7 of Figs. 3 and 4 are formed on short sides between the adjacent positioning holes 3. Also, in a modified embodiment of the dividing ridge 7, the pair of downwardly inclined surfaces 7a and 7b forming the dividing ridge 7 are formed as far as a midway of each positioning hole as shown in Fig. 5, or formed as far as the exit of each positioning hole as shown in Fig. 6. In this way, as is shown in Figs. 10(A) through 10(C), when the IC mount table 2 is assembled to the group of contacts 1 arranged in parallel relation and at micro pitches on the socket board 4, the respectively contacts 1 are surely portioned out rightwardly and leftwardly by the dividing ridges 7 of the partition walls 6 for partitioning the adjacent positioning holes 3 arranged in parallel relation and at micro pitches on the IC mount table 2. As a result, the group of positioning holes 3 can be properly corresponded to and inserted into the group of contacts 1 as one group. That is, even when a part of the group of contacts 1 is one sided, the contacts 1 can be correctly guided into the corresponding positioning holes 3 by slidingly portioning out the contacting portions 1b of the tips of the contacts by the downwardly inclined surfaces 7a and 7b formed on the dividing ridges 7. In this case, as is shown in Fig. 7, the contacting portions of the tips of the contacts 1 are held in a state hidden into the positioning holes 3. Or as a modified embodiment shown in Fig. 8, the contacting portions of the tips of the contacts 1 are held in a state projecting outwardly from the exit side of the positioning holes 3. As is shown in Fig. 7, a flat IC 9 is placed on the IC mount table 2. By closing an IC presser cover 10 relative to the socket board 4 in the way as shown in Fig. 9, the IC 9 is pressed together with the IC mount table 2 downwardly against the spring 5, and as the reaction, the contacting portions 1b of the tips of the contacts 1 are abutted against IC contacting pieces 9a and bent to obtain a contacting pressure by a restoring force thereof. Furthermore, as is shown in Fig. 8, the flat IC 9 is contacted to the contacting portions 1b of the tips of the contacts 1 projecting from the positioning holes 3 and placed on the IC mount table 2. Then, as is shown in Fig. 9, the same contacting relation as mentioned above can be obtained by closing the IC presser cover 10 relative to the socket board 4. As is shown in Figs. 1, 2, and 7 through 9, the peripheral four sides or two sides of the IC mount table 2 are projected in a pillow shape to form an IC supporting pad 11, and the positioning holes 3 are opened up at the IC supporting pads 11. Furthermore, as is shown in Figs. 7 and 9, the IC presser cover 10 is provided with an IC pressing pad 12 corresponding to the IC supporting pad 11 and projecting from the inner surface of the IC presser cover 10. Angular edges 12a of the presser surface of the IC presser pad 12 and the angular edges 11a of the supporting surface of the IC supporting pad 11 are formed in an arcuate shape, respectively. The edge portion of the IC 9 is held between the IC presser pad 12 and the IC supporting pad 11 to realize the contacting relation with the contacts 1. At that time, the angular edges 12a of the presser surface and the angular edges 11a of the supporting surface are formed in an arcuate shape, respectively, in order to prevent the IC contacting pieces 9a and the outer surface of the body of the IC 9 from being damaged. As described in the foregoing, according to the present invention, when the IC mount table is assembled to the group of contacts arranged in parallel relation and at micro pitches on the socket board, the contacts can be accurately portioned out rightwardly and leftwardly by the dividing ridges of the partition walls for partitioning the adjacent positioning holes arranged in parallel relation and at micro pitches, and then the group of positioning holes can be properly corresponded to and inserted into the group of contacts as one group. As a result, the work for corresponding the group of positioning holes to the group of contacts for assembly can be performed easily and rapidly. Therefore, there can be effectively eliminated such inconvenience as to deform the contacts by mistake when the IC mount table is assembled. Furthermore, even when a part of the group of contacts is one sided, the contacts can be correctly guided into the corresponding positioning holes by slidingly portioning out the contacting portions of the tips of the contacts by the downwardly inclined surfaces forming the dividing ridges.

Claims: An IC socket, comprising: a socket board (4) including an IC socket mount table (2); a plurality of contact (1) arranged in parallel relation on said socket board, said contacts having tips which have contacting portions (1b) thereon; and a plurality of positioning holes (3) arranged in parallel relation on a marginal portion of said IC mount table for receipt of said contacting portions of said tips of said contacts for contacting contact portions (9a) of an IC (9) when placed on said IC mount table, adjacent pairs of said positioning holes having a common partition wall (6), and each said partition wall having tapered surfaces (7a, 7b) on opposite sides thereof tapering to a linear point intersection (7c) for smoothly guiding said contacting portions from between adjacent said positioning holes into a respective said positioning hole. The IC socket of Claim 1, wherein said positioning holes are rectangular in shape and arranged in said parallel relation in a linear pattern, said common partition wall forming one rectangular side for each said positioning hole of said adjacent pair of positioning holes. The IC socket of Claim 1, wherein said positioning holes are rectangular in shape and arranged in said parallel relation in a zig-zag pattern, said common partition wall forming one rectangular side for each said positioning hole of said adjacent pair of positioning holes. The IC socket of Claim 1, wherein said common partition wall has said tapered surfaces thereon only on a lower half thereof. The IC socket of Claim 1, wherein said common partition wall has said tapered surfaces thereon over their entire extent.

Inventors: MATSUOKA NORIYUKI, URATSUJI KAZUMI, MATSUOKA, NORIYUKI, URATSUJI, KAZUMI
Applicants: YAMAICHI ELECTRONICS CO LTD, YAMAICHI ELECTRONICS CO., LTD.
Application year: 1990
Main classification: H05K7
IPC codes: A45C3, H01R33, H01R13, H05K7