Electrical connector with socket contacts of different sizes having means for preventing erroneous connection

Abstract: An electrical connector comprising a plurality of socket contacts of different cross sectional sizes and an insulator housing having a plurality of conduits accommodating the socket contacts. In order to insure accommodation of the socket contacts in the corresponding conduits, each socket contact has one or more lateral projection and the corresponding conduit accompanies a lateral groove for receiving the lateral projection so that the socket contact is inserted in the corresponding conduit with a predetermined attitude. Further, in order to prevent a small sized socket contact from being erroneously inserted in one of conduits for accommodating a large sized socket contact, the lateral projections of the small socket contact are formed so that one of the lateral projections exceeds the lateral groove of the conduit for the large socket contact and cannot be inserted into both of the large conduit and its groove.

Description: The present invention relates to an electrical connector. A series of conventional electrical connectors for use in connection with wires is shown in the US Patent 4,764,129. Such a known series of electrical connectors comprises a plurality of sockets having hollow active portions which are different from one another in a cross-sectional size for receiving plugs of different cross-sectional sizes. In such conventional electrical connectors a large size plug can not be accommodated in a small socket because of its large cross-sectional size. Further, an erroneous connection wherein a small-size plug is accommodated in a large socket is prevented by a large key formed on the top side of the small plug, whereas the large socket has a small keyway fitting only the narrow key on the larger plug. The EP-A-0,223,586 discloses an electrical connector wherein an erroneous orientation of the socket contact is prevented by a projection 82 engaging a mating keyway at the connector body. According to the present invention, an electrical connector is provided as defined in Claim 1. Fig. 1 is a perspective view of an electrical connector according to one embodiment of the present invention with socket contacts being disassembled from an insulator housing; Fig. 2 is a cross-sectional view of a small socket contact of the electrical connector of Fig. 1; Fig. 3 is a cross-sectional view of a large socket contact of the electrical connector of Fig. 1; Fig. 4 is a partial cross-sectional view of the connector with the small socket contact of Fig. 2 being accommodated in a corresponding conduit of the housing; and Fig. 5 is a partial cross-sectional view of the connector with the large socket contact of Fig. 3 being accommodated in a corresponding conduit of the housing. Referring to Fig. 1, the electrical connector shown therein comprises two types of socket contacts 10 and 20 of different sizes and an insulator housing 30 having conduits 31-35 for receiving the socket contacts 10 and 20 therein. The socket contact 10 of one type has a can-type hollow active portion 11 of a small cross-sectional size. Accordingly, the socket contact 10 is called a small socket contact. On the other hand, the socket contact 20 of the other type has a can-type hollow active portion 21 of a large cross-sectional size. Accordingly, the socket contact 20 is called a large socket contact. The conduits 31-33 and 34-35 are different in cross-sectional size and are capable of accommodating the socket contacts 10 and 20, respectively. The term "cross-sectional size" with respect to each of socket contacts 10 and 20 and conduits 31-35 means a sectional size sectioned in a direction perpendicular to a longitudinal direction thereof. The small socket contact 10 is made by bending a metal plate and is further provided with a wire-connecting portion 12 to which a wire is connected and a pair of lateral projections 13a and 13b which laterally extend from a connecting portion between the active portion 11 and the wire-connecting terminal 12. The lateral projections 13a and 13b extend in a direction perpendicular to the longitudinal direction of the socket contact 10, that is, in the vertical direction in the figure. Referring to Fig. 2, the active portion 11 of the small socket contact 10 has a height H A and a width W A . I A represents a vertical size or a height of the socket contact 10 including the projections 13a and 13b. Returning to Fig. 1, the large socket contact 20 is made of the same material as that of the small socket contact 10 and is provided with a wire-connecting terminal 22 and a lateral projection 23a which laterally extends from a connecting portion between the active portion 21 and the wire-connecting terminal 22. The lateral projection 23a extends in a lateral direction or upward as shown in Fig. 1. Referring to Fig. 3 illustrating the dimensions of the cross-section of the large socket contact 20, the active portion 21 has a height H B and a width W B , the height of the large socket contact 20 including the lateral projection 23a is I B . Referring to Fig. 1 again, each of conduits 31-33 in the housing 30 is for receiving the small socket contact 10 and has a cross-sectional size which is slightly larger than the contour of the active portion of the small socket contact 10. Therefore, each of the conduits 31-33 is called a small conduit. The small conduit 31 is accompanied with two grooves 31a and 31b for receiving the lateral projections 13a and 13b of the small socket contact 10. That is, the insulator housing 30 is formed with each of the grooves 31a and 31b laterally extending from the small conduit 31 and also extends along the small conduit 31. Each of the other small conduits 32 and 33 also has a pair of grooves 32a-32b and 33a-33b for receiving the lateral projections 13a and 13b. The lateral projections 13a and 13b of the small socket contact 10 are formed at predetermined angular positions on the small socket contact 10. While, the lateral grooves 31a and 31b, 32a and 32b and 33a and 33b are also formed at predetermined angular positions of the small conduit 31-33. Therefore, the small socket contact 10 is inserted into the small conduit 31-33 with a correct orientation, as shown in Fig. 4. In the figure, 40 represents an insulated wire connected to the wire-connecting portion of the socket contact 10. If the small socket contact 10 is intended to be inserted into the small conduit 31-33 without the correct orientation, the small socket contact 10 cannot be inserted in the small conduit 31-33. Therefore, the lateral projections 13a and 13b serve as a stopper for preventing the small socket contact 10 to be inserted into the small conduit 31, 32 or 33 with an erroneous orientation. The large conduit 35 is also accompanied with a groove 35a for receiving the lateral projection 23a of the large socket contact 20. That is, the insulator housing 30 is formed with the groove 35a laterally extending from the large conduit 35 and also extends along the large conduit 35. The other large conduit 34 also has a groove 34a for receiving the lateral projection 23a. The lateral projection 23a of the large socket contact 20 are formed at a predetermined angular position on the large socket contact 20. While, the lateral groove 34a and 35a are also formed at a predetermined angular positions of the large conduit 34-35. Therefore, the large socket contact 20 is inserted into the large conduit 34-35 with a correct orientation, as shown in Fig. 5. If the large socket contact 20 is intended to be inserted into the large conduit 34-35 without the correct orientation, the large socket contact 20 cannot be inserted in the large conduit 34-35. Therefore, the lateral projection 23a serves as a stopper for preventing the large socket contact 20 to be inserted into the large conduit 34 or 35 with an erroneous orientation. The large socket contact 20 cannot be inserted into any one of the small conduits 31-33 because the large active portion 21 has a cross sectional size larger than that of the cross-sectional size of the small conduit 31-33. On the other hand, the lateral projections 13a and 13b of the small socket contact 10 are made with sufficient dimensions so that the lateral projections 13a and 13b bars insertion of the small socket contact into the large conduit 34 or 35 in any orientation or attitude. In order to prevent the small socket contact 10 from being inserted in the large conduit 34 and 35, the following conditions are met with respect the dimensions of each part of the electrical connector: For socket contacts 10 and 20; H B > H A , W B > W A , I A > I B For conduits 31-35; H D > H C , W D > W C , I C > I D For socket contacts and conduits; H D > H B > H C > H A , W D > W B > W C > W A , I B > W D , I B > H D , > I A > H C , I C > I A > I D > I B . H D , H C , W D , W C , I C and I D represent dimensions of the small and large conduits 31 and 35, as shown in Fig. 1. Under the above-described conditions, the small socket contacts 10 cannot be inserted into the large conduits 34 and 35 in any attitude, because one of the lateral projections 13a and 13b exceeds the groove 35a and is inserted in neither conduit 35 nor lateral groove 35a. In the above embodiment, the "erroneous connection" in connection with the socket contacts has been treated as such cases: (1) a wrong orientation of the socket contact in the conduit; (2) accommodation of the large socket contact in the small conduit; and (3) accommodation of the small socket contact in the large conduit. A case of the same size connection such as accommodation of the small socket contact 10 in the small conduit 31, 32 or 33 is treated as non-erroneous connection. However, if small socket contacts having the active portions of the same cross-sectional size are made to have different lateral projections in shape, angular position and/or number, and if the corresponding small conduits are made to have grooves for receiving those lateral projections, each of the small socket contacts, even if they have active portions of the same size, can be inserted only in the corresponding small conduit but not inserted in the other small conduits. For example, one of two small socket contacts 10 is made to have two lateral projections 13a and 13b while the other small socket contact 10 is made to have a single lateral projection similar to the lateral projection 23a in Fig. 1, and if the small conduit 31 has the grooves 31a and 31b as shown in Fig. 1 while another small conduit 32 has a single groove similar to 35a in Fig. 1, the former small socket contact 10 having two lateral projections and the latter small socket contact having a single lateral projection can be inserted in small conduit 31 having two grooves and the other small conduit 32 having one groove, respectively, but the former socket contact having two lateral projections and the latter socket contact having a single lateral projection cannot be inserted in the conduit 32 having a single groove and the other conduit 31 having two grooves, respectively. In the above-mentioned embodiment, although the present invention has been described in an electrical connector having socket contacts having active portions of two different cross-sectional sizes, it is not limited thereto but is applicable to an electrical connector having socket contacts having active portions of three or more different sizes. In practice, a securing member is provided for fixing or securing each of the socket contacts 10 and 20 in the corresponding one of the conduits 31-35 in the housing 30 to prevent disengagement of the socket contact with the housing after the socket contact is inserted in the corresponding conduit. However, the securing member is conventionally known and is not related to the present invention, it is not shown in the figures. The present invention has been described in connection with the embodiment using two types of socket contacts having can-type hollow active portions, the present invention can be applied to electrical connectors using more than two types of socket contacts. The shape of the active portion of the socket contacts is not restricted to the can-type but may be any other shape.

Claims: An electrical connector comprising: a first socket contact (20) having a hollow active portion for receiving a plug contact; the first socket contact (20) having a large cross-sectional size of said hollow active portion; a second socket contact (10) having a hollow active portion for receiving a plug contact; the second socket contact (10) having a small cross-sectional size of said hollow active portion; and an insulator housing (30) having a first and a second conduit (31-35), the first conduit (34,35) having a large size and the second conduit (31,32,33) having a small size, which are for fixedly accommodating said first and said second socket contacts (10, 20), resp.; wherein each said first and said second socket contacts (10, 20) has a first and second opposite side surfaces extending along opposite planes, resp., which are spaced parallel to each other; said first socket contact (20) has a single first projection (23a) laterally extending from said first side surface along one of said opposite planes said second socket contact (10) has two second projections (13a, 13b) laterally extending from said second side surface along the other one of said opposite planes in opposite directions for serving as a stopper to prevent said second socket contact (10) from being accommodated in said first conduit (34-35), said first conduit (34-35) has a single first groove (35a) being formed in said insulator housing (30) to extend from said first conduit (34-35) in a lateral direction for receiving said first projection (23a), said second conduit (31-33) has two second grooves (31a, 31b) being formed in said insulator housing (30) to extend from said second conduit (31-33) in opposite lateral directions for receiving said second projections (13a, 13b).

Inventors: ENDO HIROSHI C O JAPAN AVIATON, ENDO, HIROSHI, C/O JAPAN AVIATON ELEC.IND.LTD.
Applicants: JAPAN AVIATION ELECTRON, JAPAN AVIATION ELECTRONICS INDUSTRY, LIMITED
Application year: 1990
Main classification: H01R13
IPC codes: H01R13, G01B3