Electrical connector for printed circuit boards

Abstract: The object of the present invention is to provide an electrical connector which makes it possible to achieve simple ground interconnection between two printed circuit boards. Contacts (134, 136, 154, 156) for ground and signal which electrically contact each other are respectively secured in housings of a plug connector (150) and a cap connector (130), with the contacts being positioned in two rows in each connector. The cap connector (130) includes shield plates (170) attached to the side surfaces of the housing (152) of the cap connector. Said shield plates (170) being connected to the ground contact (154) of the plug connector and the ground contacts (134) are of the plug connector (130).

Description: The present invention concerns an electrical connector equipped with two connector halves which are respectively mounted on different boards, and which connect these boards to each other. In the past, electrical connectors have been widely used in order to connect printed circuit boards, hereafter referred to as "PCB's", to each other. Such electrical connectors as disclosed in U.S. Patent No. 5,224,866 are equipped with a plug connector and a cap connector which are mounted on different boards, and which are connected to each other. The PCB's are connected to each other by connecting the plug connector and cap connector. The plug connector and cap connector each have a plurality of contacts, and a housing in which these contacts are lined up at a given pitch. Ordinarily, the contacts lined up in the housing of the plug connector possess spring forces, so that when the plug connector and cap connector are connected, the contacts lined up in the respective housings are caused to contact each other with a given force as a result of these spring forces, thus establishing an electrical connection. In many applications, there exists a need for ground interconnection between the boards. In another type of a connector assembly, this interconnection is established through ground contacts on a first connector and shielding plates in moulded in a second connector; see EP-A-0 627 788. As a result of the miniaturization of electrical connectors in recent years, there has been a tendency for the contacts to become smaller, and for the pitch at which the contacts are lined up to become narrower. Furthermore, there has also been a tendency for the contacts to become shorter, in order to reduce the distance between the connected boards when the boards are connected face-to-face by such an electrical connector. In cases where the contacts are thus made smaller and shorter, the spring forces of the contacts drops so that there is a drop in the contact pressure between the contacts, thus leading to the danger of an inadequate electrical connection. The object of the present invention is to provide an electrical connector which makes it possible to provide simple and reliable ground interconnection. The object is achieved with an electrical connector with the features of claim 1. It is advantageous that, when the plug and cap connectors are connected to each other in the electrical connector, the first contacts are clamped between the wall surfaces of the housing of the plug connector and the second contacts. In other words, when the plug and cap connectors are connected to each other, the first contacts are clamped between the wall surfaces and the second contacts, and are strongly pressed against both of these parts. As a result, even if the contacts are made smaller and shorter in order to reduce the pitch of the contacts, the first contacts and second contacts can be caused to wipingly contact each other with a high contact pressure. Furthermore, the first contacts are lined up in two rows so that the first and second spring members are mutually symmetrical in the opposing rows. As a result, the respective forces from the wall surfaces and the second contacts are balanced between the two rows, so that the first contacts and second contacts can be caused to contact each other with a high well-balanced contact pressure. Thus, an electrical connector which provides a secure electrical connection can be obtained. Embodiments of an electrical connector and of the present invention will now be described by way of example with reference to the accompanying drawings in which: Figures 1 - 4 illustrate a plug connector a of an electrical connector. Figure 1 is a plan view, Figure 2 is a side view, Figure 3 is an end view, and Figure 4 is a schematic plan view of a board on which the plug connector is mounted. Figure 5 is a cross-sectional view of the plug connector shown in Figures 1 - 4. Figures 6 - 9 illustrate a cap connector of the electrical connector. Figure 6 is a plan view, Figure 7 is a side view, Figure 8 is an end view, and Figure 9 is a schematic plan view of a board on which the cap connector is mounted. Figure 10 is a cross-sectional view of the cap connector shown in Figures 6-9. Figure 11 is a cross-sectional view which illustrates the connected state of the plug connector shown in Figures 1-4 and the cap connector shown in Figures 6-9. Figures 12-14 illustrate another embodiment of a cap connector of the electrical connector. Figure 12 is a plan view, Figure 13 is a side view, and Figure 14 is an end view. Figure 15 is a cross-sectional view of the cap connector shown in Figures 12-14. Figure 16 is a side view which illustrates a cap connector in a first embodiment of the electrical connector of the present invention. Figure 17 is a cross-sectional view which shows the cap connector in Figure 16 connected with a plug connector, illustrating the electrical contact between the ground contacts of the cap connector and the ground contacts of the plug connector. Figure 18 is a cross-sectional view which shows the cap connector in Figure 16 connected with a plug connector, illustrating the electrical contact between the signal contacts of the cap connector and the signal contacts of the plug connector. Figure 19 is a side view which illustrates the cap connector in a second embodiment of the electrical connector of the present invention. The general layout of the electrical connector and the special features of the contacts of the connector will be described with reference to Figures 1 through 11. Figures 1 - 5 illustrate the plug connector of the electrical connector. Figure 11 shows the plug connector and cap connector connected to each other. The electrical connector 10 (Figure 11) has a plug connector 20 and a cap connector 60 which are connected to each other. The plug connector 20 is mounted on a board 12, and the cap connector 60 is mounted on a board 14. When the plug connector 20 and cap connector 60 are connected to each other, the boards 12 and 14 are connected to each other face-to-face as shown in Figure 11. The plug connector 20 (Figs. 1-5) is equipped with a housing 30 and contacts 40. The contacts 40 have projections, for press fitting into contact-receiving cavities of the housing 30 so as to be fastened to the housing 30, and they are aligned in two rows in the direction of the length of the housing 30. The housing 30 has posts 32 and 34 which are respectively inserted into post holes 12a, 12b formed in the board 12, and a metal-fastening fitting 36 which is soldered to a fastening pad 12c on the board 12. Furthermore, a central wall 38 which extends in the direction of the length of the housing 30 is formed in the central part of the housing 30. This central wall 38 has two wall surfaces 38a and 38b. Contacts 40 are comprised of contact sections 41 including S-shaped first spring members 42 which have two bent portions 42a and 42b, second spring members 44 which have contact projections 44a that electrically contact the contact sections 82 of contacts 80 described later, and termination sections 46 which are soldered to conductive pads 12d on the board 12. The contact legs 42c of the first spring members 42 substantially contact the wall surfaces 38a and 38b, while the second spring members 44 via contact projections 44a contact the contact sections 82 of the contacts 80. The contacts 40 are formed by stamping from single metal plates, which are superior in terms of conductivity and spring characteristics. The contacts 40 are installed at a pitch of 0.6 mm, and the height of the contacts 40 from the board 12 is approximately 3.00 mm. The cap connector 60 is equipped with a housing 70 and contacts 80. The contacts 80 are lined up in two rows along the length of the housing 70. The housing 70 is equipped with posts 72 and 74 as shown in Figure 7 which are respectively inserted into post holes 14a and 14b formed in the board 14, and a metal-fastening fitting 76 which is soldered to a fastening pad 14c on the board 14. Furthermore, side walls 78 which extend in the direction of length of the housing 70 are formed on both side portions of the housing 70. Contacts 80 are comprised of contact sections 82 which electrically contact the contact projections 44a of the second spring members 44 of the contacts 40, and termination sections 84 which are soldered to conductive pads 14d on the board 14. The contacts 80 are formed by stamping and bending single metal plates which are superior in terms of conductivity and spring characteristics. The contacts 80 are installed at a pitch of 0.6 mm, and the height of the contacts 80 from the board 14 is approximately 3.0 mm. When the plug connector 20 and cap connector 60 are connected, as shown in Figure 11, the first and second spring members 42 and 44 of the contacts 40 are clamped between the wall surfaces 38a and 38b and the contact sections 82 of the contacts 80. Furthermore, when the contact projections 44a of the second spring members 44 are pressed against the contact sections 82 of the contacts 80, the first and second spring members 42 and 44 apply a force on the contacts 80. Thus, when the plug connector 20 and cap connector 60 are connected, the contacts 40 are clamped between the wall surfaces 38a and 38b and the contacts 80, and are strongly pressed against both the wall surfaces 38a and 38b and contacts 80. Accordingly, even if the contacts 40 are made smaller and shorter in order to reduce the pitch of the contacts 40, the contacts 40 and contacts 80 electrically and wipingly contact each other with a high contact pressure. Furthermore, since the contacts 40 are arranged in two rows so that the first and second spring members 42 and 44 of the contacts 40 are mutually symmetrical in the opposing rows, the respective forces between contacts 40 and 80 are balanced between the rows of contacts 40, so that the contacts 40 and contacts 80 contact each other with a high well-balanced contact pressure, thus making it possible to obtain an electrical connector which provides secure electrical connections. A second embodiment of the electrical connector will be described with reference to Figures 12-15: The electrical connector of the second embodiment has a different cap connector. The plug connector has the same shape as the plug connector in the first embodiment. Accordingly, the cap connector will be described here. The cap connector 90 is equipped with a housing 100 and contacts 120. The contacts 120 are lined up in two rows along the length of the housing 100. Compared to the contacts 80 of the cap connector 60 shown in Figures 6-9, the contacts 120 are longer, with a length of approximately 9.00 mm. The housing 100 is equipped with posts 102 and 104 which are respectively inserted into post holes 14a and 14b formed in the board 14, and a metal-fastening fitting 106 which is soldered to a fastening pad 14c on the board 14. Furthermore, side walls 108 extend in the direction of the length of the housing 100 and are formed with openings 108a. These openings are a characteristic feature of the cap connector 90. The reason for forming the openings 108a will be described below. The housing 100 is ordinarily made of a synthetic resin, and is formed by injection molding using a mold which corresponds to the shape of the housing 100. The contacts 120 are inserted into the housing 100 after the housing 100 has been molded. The spaces into which the contacts 120 are inserted are formed in the injection-molded walls of the housing 100 using long, slender pins known as core pins. After the housing 100 has been injection-molded, these core pins are removed from the housing 100. In cases where the contacts 120 are long, the core pins are also naturally long, so that there is a danger that bending will occur when the core pins are pulled out of the housing 100. Accordingly, the openings 108a are formed in the side walls 108 of the housing 100 in order to allow shortening of the core pins even in cases where the contacts 120 are long. By thus forming the openings 108a, it is possible to use a metal mold in the areas corresponding to the openings 108a during injection molding. Furthermore, two short core pins which are respectively inserted from above and below are used in each area corresponding to a space into which one of the contacts 120 is to be inserted. By thus using two short core pins to form spaces for the insertion of long contacts, it is possible to prevent bending of the core pins when they are pulled out of the housing 100 following injection molding. An embodiment of the electrical connector of the present invention will be described with reference to Figures 16-18. The electrical connector 128 of this embodiment is characterized by shield plates 170 which are attached to the side surfaces of walls 158 of the housing 152 of the cap connector 150, and by the shape of the ground contacts among the contacts of the plug connector. The electrical connector 128 of this embodiment is equipped with a plug connector 130 and a cap connector 150 which are substantially similar in shape to the plug connector 20 and cap connector 60 of the electrical connector 10 of the first embodiment illustrated in Figures 1 through 11. Ground contacts 134 and signal contacts 136 are arranged in the housing 132 of the plug connector 130. Furthermore, ground contacts 154 and signal contacts 156 are also arranged in the housing 152 of the cap connector 150. Moreover, shield plates 170 are respectively attached to both side surfaces of walls 158 of the housing 152 of the cap connector 150. This attachment is accomplished by causing the shield plates 170 to slide relative to the housing 152 so that respective projections 158a formed on the side surfaces of walls 158 enter the narrow portions 172a of slots 172 formed in the shield plates 170. Bridge contact sections S1 (supported at both ends) on which dimples 174 are formed, and tongue members S2 which are used to make spring contact with the ground contacts 154 of the cap connector 150, are formed on the shield plates 170. When the plug connector 130 and cap connector 150 are connected, the bridge contact sections S1 of the shield plates 170 contact the extensions 134a of the ground contacts 134, and the tongue members S2 springably contact the termination sections 154a of the ground contacts 154. If necessary, the tongue members S2 and the termination sections 154a of the ground contacts 154 may be soldered. Furthermore, in the assembly process, the termination sections 154a of the ground contacts 154 are soldered to the conductive pads 14d on board 14. Accordingly, the heat generated when the cap connector 150 is mounted on the board 14 may be utilized in order to solder the tongue members S2 and the termination sections 154a of the ground contacts 154. As is shown in Figure 18, the signal contacts 136 and 156 do not contact the shield plates 170. Furthermore, the housing 152 of the cap connector 150 has projecting portions 159, and grooves 160 which accommodate the projecting portions 138 of housing 132 at which the contact sections S1 and extensions 134a are located. The assembly process is as follows: The shield plates 170 are first attached to the housing 152 of the cap connector 150, after which the contacts 154 and 156 are positioned into the housing 152. Soldering is performed only when the cap connector 150 is attached to the board. Dimples 174 are formed in the shield plate 170, and these dimples 174 electrically contact the extensions 134a of the ground contacts 134. However, it would also be possible to omit the dimples 174. In the electrical connector of this first embodiment of the invention, the respective ground contacts 134 and 154 can easily be connected by attaching a single shield plate 170 to the housing 152 of the cap connector 150. Figure 19 illustrates a second embodiment of the electrical connector of the present invention. The difference between this electrical connector and the electrical connector of the first embodiment lies in the shape of the shield plates. In the shield plates 180 of the electrical connector of this second embodiment, no projections are formed in the tongue members in order to prevent sagging of the slots 182. An effect similar to that obtained using the shield plates 170 shown in Figure 16 can also be obtained using these shield plates 180.

Claims: An electrical connector assembly for electrical connection to conductive pads on board members (12, 14) comprising a plug connector (130) including at least one row of electrical contacts (134, 136) with ground contacts (134) and signal contacts (136) arranged in the same row, the row extending along the plug housing (132), said electrical contacts including resilient contact sections extending in the mating direction from a base of the housing and termination sections for electrical connection to the conductive pads on one of the board members and a cap connector (150) including at least one row of electrical contacts (154, 156) with complementary ground contacts (154) and signal contacts (156) arranged in the same row, the row extending along an inner side of a cap housing (152), the electrical contacts (154, 156) including contact sections electrically connecting with the resilient contact sections of the plug connector when the plug connector and cap connector are mated together and termination sections (154 a) for electrical connection with the conductive pads of the other of the board members, characterised in that : said cap connector (150) includes shield plates (170) attached to side surfaces of said housing (152), said shield plates (170) being connected to said ground contacts (154) and establishing ground interconnection to the other board member through said ground contacts (154) and to the ground contacts (134) of the plug connector (130) when the plug and cap connectors (130, 150) are mated together. The electrical connector assembly of claim 1, characterised in that , said shield plates (170) have a plurality of tongue members (52) to make contact to the termination sections (154 a) of said ground contacts (154) whereby ground interconnection between said shield plates (170) and said other board member is achieved through said ground contacts (154). The electrical connector assembly of anyone of claims 1 or 2, characterised in that , said shield plates (170) have a plurality of bridge contact sections (S1) for contacting the ground contacts (134) of the plug connector (130) when the cap and plug connectors (150, 130) are mated together. The electrical connector assembly of anyone of claims 1, 2 or 3, characterised in that , said ground contacts (134) of the plug connector (130) have extensions (134 a) for contacting with said shield plates (170). The electrical connector assembly of claim 3, characterised in that , dimples (174) are formed on said bridge contact sections (S1), said dimples electrically contacting the ground contacts (134) when the cap and plug connectors (150, 130) are mated together. The electrical connector assembly of anyone of claim 1 to 5, characterised in that , the termination sections of both said ground and signal contacts (154, 156) of the cap connector (150) have a common shape. The electrical connector assembly of claims 1 to 6, characterised in that , the tongue members (S2) of the shield plates (170) are used to make spring contact with said ground contacts (154) of the cap connector (150). The electrical connector assembly of anyone of claims 1 to 7, characterised in that , the tongue members (S2) of the shield plates (170) are soldered to said ground contacts (154) of the cap connector (150). The electrical connector assembly of anyone of claims 1 to 8, characterised in that , the housing (152) of the cap connector (150) has projecting portions (159) and grooves (160) which accommodate projecting portions (138) of housing of housing (132) of the plug connector (130) at which the bridge contact sections (S1) are located. The electrical connector assembly of anyone of claims 1 to 9, characterised in that , each contact (134, 136) of the plug connector (130) includes a base portion having a beam extending upwardly therefrom, the beam including a contact section thereon for mating with a corresponding linear contact (154, 156) of the cap connector (150), the beam further including an S-shaped spring portion extending from the end thereof, the spring portion extending to an end portion that is substantially at the same height as the contact section on the upstanding beam. The electrical connector assembly of claim 10, characterised in that , upon mating the plug and cap connectors (130, 150) the spring end portion presses against a central wall of the plug connector (130) such that the S-shape contact sections of the plug connector are springably clamped between the linear contact sections of the cap connector (150) and the wall of the plug housing (132).

Inventors: KUSHUHARA TOSHITAKA, KUSHUHARA, TOSHITAKA
Applicants: WHITAKER CORP, THE WHITAKER CORPORATION
Application year: 1995
Main classification: H01R12
IPC codes: H01R12