Three-way nip contact type contactor

Abstract: A three-way nip contact type contactor has first, second and third contacting pieces connected together at their basic end portions and arranged side by side in rows toward their foremost end portions thereof. The first and second contacting pieces are arranged to form two sides of a triangle and the third contacting piece is arranged to form the remaining side. A male terminal is nipped by and among the first through third contacting pieces to obtain a contacting relation between the male terminal and each of the first and third contacting pieces. The third contacting piece is provided at its foremost end portion with a pressure bearing portion. The third contacting piece, when an external force is applied to the pressure bearing portion, is displaced in an opening direction against its elasticity to permit the male terminal to be inserted into among the first through third contacting pieces. When the third contacting piece is elastically restored in a closing direction and pressed against a side surface of the male terminal, the first and second contacting pieces are displaced in the opening direction against their elasticity by an pressing force of the third contacting piece, and slidingly moved on the side surface of the male terminal during their displacements in the opening direction.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a three-way nip contact type contactor designed to nip a male contact from three ways in order to obtain an electrical contact therewith. 2. Background of the invention Japanese Utility Model Early Laid-open Publication No. Hei 1-165578 discloses a contactor provided with first and second contacting pieces which form two sides of a triangle, and a third contacting piece which forms the remaining side. In this prior art, a male terminal of an IC, etc. is forcedly inserted into among the first, second and third contacting pieces, thereby dilating the respective contacting pieces in the opening direction against the elasticity thereof and obtaining a pressure contact between the male terminal and the first through third contacting pieces by the restoring force thereof. However, the above-mentioned contactor has such problems as that resistance is large when the male terminal is inserted into among the first, second and third contacting pieces, and in addition, insertion, and therefore, removal, becomes difficult where the number of poles of male terminals are increased as in the case of a pin grid array type IC. Because of the above-mentioned problems, this conventional contactor is practically impossible to be used for a multipolar IC such as pin grid array type IC. Therefore, it remains as a subject to be tackled with that while solving the above-mentioned problems, a high reliability of contacting relation is obtained by taking advantage of the three-way contact. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a three-way nip contact type contactor, in which a male terminal can be inserted into among first, second and third contacting pieces with no load and yet a high reliability of contacting relation can be obtained. The invention provides a three-way nip contact type contactor in accordance with Claim 1. With the above-mentioned construction of the three-way nip contact type contactor of the present invention, when an external force is applied to the pressure bearing portion formed on the foremost end of the third contacting piece, the third contacting piece is displaced in the opening direction against elasticity thereof in order to permit the male terminal to be inserted into among the first through third contacting pieces. Further, when the first contacting piece is elastically restored and pressed against the side surface of the male terminal, the first and second contacting pieces are displaced in the opening direction against elasticity thereof by the pressing force of the third contacting piece and slidingly moved on the side surface of the male terminal. Owing to the sliding movements of the first and second contacting pieces on the side surface of the male terminal, an active metallic surface is exposed and a wholesome and reliable electric contacting relation can be attained. The above and other objects, characteristic features and advantages of the present invention will become more apparent from the detailed description of the preferred embodiment set forth hereinbelow with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Figs. 1 through 8 show the preferred embodiment of a three-way nip contact type contactor according to the present invention, wherein: Fig. 1 is a plan view of a three-way nip contact type contactor illustrated for the purpose of explaining the sliding movements of first and second contacting pieces with respect to a male contact; Fig. 2 is a perspective view of the contactor; Fig. 3 is likewise a perspective view of the contactor but when viewed from a different direction; Fig. 4 is an expanded view (view showing a punched-out state of the contactor from a plate material) of the contactor; Fig. 5(A) is a sectional view of a socket in which the above-mentioned contactor is used and showing a state immediately before a male terminal is inserted, wherein a third contacting piece has been displaced in the closing direction; Fig. 5(B) is a plan view of the contactor in the above-mentioned state; Fig. 6(A) is a sectional view of the socket, in which the third contacting piece has been displaced in the opening direction by unidirectional lateral movement of a moving plate; Fig. 6(B) is a plan view of the contactor in the above-mentioned state; Fig. 7(A) is a sectional view of the socket, in which the male terminal has been inserted and the third contacting piece has been restored in the closing direction to realize a nippingly contacting state of the male terminal among the first through third contacting pieces; Fig. 7(B) is a plan view of the contactor in the above-mentioned state; and Fig. 8 is a vertical sectional view of the contactor showing a contacting state of the male terminal with the first through third contacting pieces in the state of Fig. 7(B). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT One preferred embodiment of a three-way nip contact type contactor according to the present invention will be described in detail with reference to Figs. 1 through 8. As previously described, a contactor 1 has first, second and third contacting pieces which are to be contacted, under pressure, with a male terminal of a generally circular configuration, etc. in section from three ways. The first through third contacting pieces are connected together at basic end portions thereof and uprighted side by side toward foremost end portions thereof. The first and second contacting pieces 3 and 4 are arranged in such a manner as to form two sides of a triangle, preferably two slant sides of an isosceles triangle, and the third contacting piece is arranged in such a manner as to form the remaining side, namely, a bottom side of an isosceles triangle. In the contactor having the first through third contacting pieces 3, 4 and 5, the third contacting piece 5 is provided at a foremost end portion thereof with a pressure bearing portion 6 to which an external force is to be applied. Upon application of an external force from its inner side, the pressure bearing portion 6 is displaced together with the first and second contacting pieces 3 and 4 in the separating direction from the first and second contacting pieces 3 and 4, namely, in the opening direction against elasticity thereof. As means for displacing the third contacting piece in the opening direction, as shown in Figs. 5 through 7, a socket substrate 7 is provided with a moving plate 8. The arrangement being such that when the moving plate 8 is laterally moved in a direction along an upper surface of the socket substrate 7, it presses the pressure bearing portion 6 of the third contacting piece 5 so as to be displaced in the opening direction. More specifically, the means for displacing the third contacting piece 5 in the opening direction is designed such that the contactor 1 is implanted in an inner bottom wall of a contactor holding hole 9 so that it is held therein, a leg portion 10 adapted to contact with a wiring board, etc. projects downwardly of the substrate 7, the pressure bearing portion 6 formed at the foremost end portion of the third contacting piece 3 projects upwardly from an opening plane of the contact holding hole 9, and this projecting portion of the foremost end portion of the third contacting piece 5 is retained at a step portion 8 formed on an inner wall of a male terminal insertion hole 11, so that when when the moving plate 8 is laterally moved in a direction as shown in Fig. 6(A), the third contacting piece 8 is pressed in the opening direction by this step portion 5. Therefore, the pressure bearing portion 6 of the third contacting piece 5 projects upwardly from foremost ends of the first and second contacting pieces 3 and 4 so as to be engaged with the moving plate 8. That is, the first and second contacting pieces 3 and 4 are of generally same height, and the foremost end portion of the third contacting piece 5 extends beyond those of the first and second contacting pieces to form the pressure bearing portion 6. As described above, the pressure bearing portion 6 is adapted to bear an external pressure applied thereto and also served as a press contacting portion for the circular male terminal 2. Further, as means for increasing an elastically restoring force of the third contacting piece 5, the pressure bearing portion 6 of the third contacting piece 5 expands back-wardly of the first and second contacting pieces 3 and 4 exceeding the upper portions thereof as shown in Fig. 5. The third contacting piece 5 is displaced backward in the opening direction into a position shown in Fig. 6 from a position shown in Fig. 5 to store an elastic force. With such stored elastic force, the pressure bearing portion 6 tends to restore the first and second contacting pieces 3 and 4, the third contacting piece 5 displaces the first and second contacting pieces 3 and 4 backward in the opening direction to attain the afore-mentioned sliding movements. As in the manner mentioned above, the first and second contacting pieces 3 and 4 are brought into contact, under pressure, with a lower part (foremost end side) of the circular male terminal 2, while the third contacting piece 3 is brought into contact, under pressure, with an upper part (basic portion side) of the male terminal 2 by the pressure bearing portion 6. Upon receipt of an external force to its pressure bearing portion 6 by the moving plate 8, etc., the third contacting piece 5, as shown in Fig. 6, is forcedly displaced in the separating direction from the first and second contacting pieces 3 and 4 to form a circular male terminal insertion entrance between the first and second contacting pieces 3 and 4, and the male terminal is inserted into this opening this no load. As is shown in Fig. 7, when elastically restored in the closing direction, the third contacting piece 5 is pressed against a side surface of the circular male terminal 2, and the second and third contacting pieces 3 and 4 are displaced in the opening direction by the pressing force of the third contacting piece 5 and contacted, under pressure, with another side surface of the male terminal 2 by elastically restoring force thereof. The first and second contacting pieces 3 and 4 are slidingly moved on the side surface of the male terminal 2 during displacement thereof. In Fig. 1, the dotted lines show the contacting positions of the first and second contacting pieces 3 and 4 with respect to the male terminal 2 at the time the third contacting piece 5 is in an initial contacted relation with the male terminal 5, while the solid lines show a state wherein the male terminal 2 is pressed and displaced by the third contacting piece 5, and the first and second contacting pieces 3 and 4 are displaced by the pressing force of the third contacting piece 5. Elastic force of the first through third contacting pieces 3, 4 and 5 is properly set so that the first and second contacting pieces 3 and 4 are in the above-mentioned relation with the third contacting piece 5. That is, the elastic force of the first and second contacting pieces 3 and 4 is set to be larger than that of the third contacting piece 5 and the pressing force of the third contacting piece 5 against the male terminal 2 is set as such that the first and second contacting pieces 3 and 4 are displaced in the dilating direction by it. The foremost end portion of the third contacting piece 5 is bent in a hook shape toward the side of the first and second contacting pieces to form the pressure bearing portion 6, and an end face of the pressure bearing portion 6 is pressed against the male terminal 2 to increase the press contacting force. The end face 13 of the pressure bearing portion 6 is a plane formed in the thickness of the plate (i.e., cutting surface) when the contactor is punched out of a plate material. Restoration of the third contacting piece 5 can be obtained by canceling the application of the external force to the pressure bearing portion 6. That is, when the unidirectional moving force of the moving plate 8 exemplified above is canceled, the third contacting piece 5 is elastically restored by its own force and the moving plate 8 is laterally moved in the other direction by its elastically restoring force. At the same time, the third contacting piece 5 is pressed against the side surface of the male terminal 2 and the first and second contacting pieces 3 and 4 are caused to be contacted, under pressure, with the side surface of the male terminal 2 and slidingly moved therealong as already described above. By such sliding movements of the first and second contacting pieces, an oxide film formed on the contacting surface is removed and an active metallic surface is exposed to attain a highly reliable contacting relation as already mentioned above. Fig. 4 shows an expanded view of the three-way nip contact type contactor when it is punched out of a plate material. As apparent from the Figure 4, the third contacting piece 5 as well as the first and second contacting pieces 3 and 4 are punched out of a plate material in such a manner as that the first and second contacting pieces 3 and 4 are located in opposite postures each other with the third contacting piece placed therebetween, and bent at the position indicated by the dotted lines in the Figure 4 to form the contactor 1. As described in the foregoing, a three-way nip contact type contactor according to the present invention includes first, second and third contacting pieces connected together at basic end portions thereof and arranged side by side in rows toward foremost end portions thereof, said first and second contacting pieces being arranged in such a manner as to form two sides of a triangle and said third contacting piece being arranged in such a manner as to form the remaining side thereof, a male terminal being nipped by and among said first through third contacting pieces to obtain a contacting relation between said male terminal and each of said first and third contacting pieces, said third contacting piece being provided at a foremost end portion thereof with a pressure bearing portion, said third contacting piece, when an external force is applied to said pressure bearing portion, being displaced in an opening direction against elasticity thereof in order to permit said male terminal to be inserted into among said first through third contacting pieces, said first through third contacting pieces being arranged such that when said third contacting piece is elastically restored in a closing direction and pressed against a side surface of said male terminal, said first and second contacting pieces are displaced in the opening direction against elasticity thereof by an pressing force of said third contacting piece, and slidingly moved on the side surface of said male terminal when they are displaced in the opening direction. Accordingly, by applying an external force to the pressure bearing portion formed on the third contacting piece, the third contacting piece is dilated so that a male terminal can be inserted into among the first through third contacting pieces with no load. Thus, the insertion of a multipole type IC, etc. into a socket is facilitated. Furthermore, when the third contacting piece is displaced in the closing direction as a result of cancellation of the external force exerted to its pressure bearing portion, it is pressed against the side surface of the male terminal, thereby displacing the first and second contacting pieces in the opening direction against elasticity thereof. The first and second contacting pieces are caused to slidingly moved along the side surface of the male terminal during their displacement. As a result, an active metallic surface is exposed to attain a wholesome contacting relation. Accordingly, there can be provided a three-way nip contact type contactor, in which the above-mentioned problems, namely, difficulty of insertion, and therefore of removal, of the group of male terminals in a three-way nip contact type contactor, can be solved and at the same time, a high reliable contacting relation can be obtained. Furthermore, in the three-way nip contact type contactor according to the present invention, by adding simple means such as proper setting of elastic force, formation of a pressure bearing portion, etc. as mentioned above, the above object can be achieved. For example, the present invention can be suitably practiced as a contactor of a socket used for the afore-mentioned pin grid array type having a plurality of circular male terminals projecting from the lower surface of an IC body. Although one preferred embodiment of the present invention has been described in detail, the present invention should not be limited to this embodiment. Various changes and modifications can, of course, be made within the scope of the claims.

Claims: A three-way nip contact type contactor (1) including first, second and third contacting pieces (3,4,5) connected together at base end portions thereof and arranged side by side in rows toward foremost end portions thereof, said first and second contacting pieces (3,4) being arranged in such a manner as to form two sides of a triangle and said third contacting piece (5) being arranged in such a manner as to form the remaining side thereof, whereby a male terminal can be nipped by and among said first through third contacting pieces to obtain a contacting relation between said male terminal and each of said first and third contacting pieces, characterized in that the foremost end portion of said third contacting piece (5) is bent in a hook-shape towards the first and second contacting pieces (6) to form a pressure bearing portion (6) which projects above the foremost ends of the first and second contacting pieces (4,5), said third contacting piece, when an external force is applied to said pressure bearing portion, being displaceable in an opening direction against the elasticity thereof in order to permit a male terminal to be inserted between said first through third contacting pieces (3,4,5), and, when said third contacting piece is elastically restored in a closing direction, said bearing portion being pressed against a side surface of said male terminal, with said first and second contacting pieces being displaced in the opening direction thereof against the elasticity thereof by a pressing force exerted by said bearing portion on said male terminal, and slidingly moved on the side surface of said male terminal when they are displaced in the opening direction as aforesaid. A three-way nip contact type contactor as claimed in Claim 1, wherein said first and second contacting pieces (3,4) lie on two equal sides of an isosceles triangle and said third contacting piece (5) lies on the base of the isosceles triangle. A three-way nip contact type contactor as claimed in Claim 1 or Claim 2, wherein the foremost end portions of said first and second contacting pieces (3,4) are of generally same height.

Inventors: URATSUJI KAZUMI, URATSUJI, KAZUMI
Applicants: YAMAICHI ELECTRONICS CO LTD, YAMAICHI ELECTRONICS CO., LTD.
Application year: 1991
Main classification: H01R23
IPC codes: H01R13, H05K7