Surface mount electrical connector

Abstract: A low profile surface mount electrical connector is adapted for connecting an electronic component such as an IC card on a planar surface of a printed circuit board which includes circuit traces thereon. The connector has a generally flat dielectric housing overmolded about a plurality of electrical terminals. The housing has a bottom surface for mounting on the printed circuit board, an opening for receiving the IC card, and a mounting bar along one side of the opening. Each terminal includes a base overmolded in the mounting bar of the housing. A beam extends from the base and includes a surface mount section for electrical connection to a circuit trace on the printed circuit board. A contact arm is joined to the beam at a U-shaped joint and extends back over the beam. The contact arm terminates in a contact portion at the opening in the housing for electrical connection to the IC card.

Description: Field of the Invention This invention generally relates to the art of electrical connectors and, particularly, to a surface mount electrical connector which has terminals for such uses as in IC card reader systems. Background of the Invention Chip (IC) cards come in a variety of shapes and sizes but typically comprise a card of approximately the same size as a standard credit card. The IC card itself contains intelligence in the form of a memory circuit or other electronic program. A card reader reads the information or memory stored on the card. IC cards are used in countless applications in today's electronic society, including ATMs, cable television decoders, cellular telephones, PC card adapters and other electronic applications. One such chip card is identified as a "Multi Media Card", or "MMC" which is an IC card for use in PC's for media applications such as adapters, music players, toys, games, cellular phones and digital cameras. The MMC card reader readily accommodates insertion and removal of the card to provide quick access to the information and programs on these cards. From EP-A-0 274 534, which is considered as the closest prior art, a connector for electrically connecting a ROM card or an IC card to a main printed wiring board is known. The connector includes a slider which causes a contact when the card is inserted. This, however is a rather complicated mechanism and is increasing the size of the connector. However, low profile electrical connectors are particularly important for the card reader connectors used in the applications described above. It has become increasingly important to limit or even reduce weight and space in electronic apparatus such as PC's where these connectors can be found. Typically, the low profile electrical connectors connect the IC card to circuit traces on a planar surface of a printed circuit board. In fact, the outer dimensions of the contacting connector in such systems often is not significantly larger than the IC card itself. Some connector manufacturers simply scale down the dimensions of a conventional connector design to achieve smaller and more dense connectors. However, simply miniaturizing the connectors compromises connector performance and reliability since smaller dimensions do not always equal the same performance and reliability of larger components. A more viable approach is to design a true surface mount electrical connector specifically applicable for such uses as IC card applications. Design parameters include minimizing size, minimizing weight, maintaining coplanarity of the connector terminals with the circuit traces on the board, resiliency of the contact beams, orienting the beams toward the IC card which, in turn, typically is toward the printed circuit board and maintaining a very low profile for the entire connector assembly. The present invention is directed to solving these design problems in a low profile electrical connector which has specific application in IC card reader systems. Summary of the Invention An object, therefore, of the invention is to provide a new and improved surface mount electrical connector. Another object of the invention is to provide a new and improved low profile surface mount electrical connector for connecting an electronic component such as an IC card on a planar surface of a printed circuit board which includes circuit traces thereon These objects are achieved with a connector according to claim 1. In the exemplary embodiment of the invention, the connector includes a generally flat dielectric housing overmolded about a plurality of stamped and formed electrical terminals. The housing has a bottom surface for mounting on the printed circuit board. An opening in the housing is provided for receiving the IC card. A mounting bar of the housing extends along one side of the opening. Each terminal includes a base overmolded in the mounting bar of the housing. A beam extends from the base and includes a generally planar surface mount section for electrical connection to a circuit trace on the planar surface of the printed circuit board. A contact arm is joined to the beam at a U-shaped joint and extends back over the beam and terminates in a contact portion at the opening in the housing for electrical connection to the IC card. As disclosed herein, the generally planar surface mount section of each terminal is wider than the beam thereof. The base of each terminal is generally planar and includes flange portions formed out of the plane of the base to anchor the base in the mounting bar of the housing. The base of each terminal is generally coplanar with the bottom surface of the housing. The beam and the surface mount section of each terminal are coplanar with the base thereof and the bottom surface of the housing. The contact arm of each terminal is narrower than the U-shaped joint thereof. The contact portion of each terminal is bowed toward the opening to present a rounded surface for engaging the IC card. The mounting bar of the housing has an outer side defining an outside edge of the housing and an inner side defining an inside edge of the opening in the housing. The beam, surface mount section and U-shaped joint of each terminal are located outside the outer side of the mounting bar. The contact arm extends over the mounted bar. The contact portion of the contact arm is located inside the inner side of the mounting bar. A top surface of the mounting bar is provided with a plurality of grooves to accommodate the contact arms of the terminals. Finally, a feature of the invention is the provision of at least one securing tab overmolded in the housing remote from the terminal. The securing tab includes a securing portion for connection to the printed circuit board. Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. Brief Description of the Drawings The features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: FIGURE 1 is a perspective view of a low profile electrical connector surface mounted on a printed circuit board, according to the invention; FIGURE 2 is an enlarged perspective view of one of the terminals of the connector; FIGURE 3,3a is a vertical section taken generally along line 3-3 of Figure 1; FIGURE 4,4a is a vertical section taken generally along line 4-4 of Figure 1; FIGURE 5 is a perspective view of an IC card about to be inserted into the connector; and FIGURE 6 is a perspective view of the IC card inserted into the connector. Detailed Description of the Preferred Embodiment Referring to the drawings in greater detail, and first to Figure 1, the invention is embodied in a low profile surface mount electrical connector, generally designated 10, for connecting an electronic component such as an IC card 12 (Figs. 5 and 6) on a planar surface 14 of a printed circuit board 16 which includes circuit traces 18 (Fig. 4) on planar surface 14. Connector 10 includes a flat dielectric housing, generally designated 20. The housing is overmolded about a plurality of stamped and formed sheet metal electrical terminals, generally designated 22. More particularly, housing 20 is a one-piece structure unitarily molded of dielectric material such as plastic or the like. The housing has a bottom surface 24 for mounting on printed circuit board 16 and an opening 26 for receiving the IC card. A window 28 in a top wall 30 of the housing exposes opening 26 as is clearly seen in Figure 1. Finally, the housing includes a mounting bar 32 on and within which terminals 22 are mounted. The mounting bar has an outer side 32a which defines an outside (rear) edge of the housing and an inner side 32b which defines an inside (rear) edge of opening 26 in the housing. A plurality of grooves 34 are formed in the top of mounting bar 32 for accommodating contact arms of terminals 22 as will be seen hereinafter. Figure 2 shows an enlarged depiction of one of the terminals 22 to show in detail the specific components or portions of the terminal. Specifically, each terminal is generally U-shaped and includes a lower leg, generally designated 36, and an upper leg, generally designated 38, with the legs being joined by a U-shaped joint 40. Lower leg 36 includes a planar base 42 which is overmolded within mounting bar 22 of housing 20. The base includes a pair of angled flanges 42a which are formed out of planar base 42 to facilitate anchoring the base in the mounting bar of the housing. A beam 44 extends rearwardly from base 42 and includes a generally planar surface mount section 46 for electrical connection, as by soldering, to a circuit trace on planar surface 14 of printed circuit board 16. It can be seen that surface mount section 46 is wider than beam 44 and includes a centrally located hole 48. The hole improves the solder joint with the circuit trace on the printed circuit board and also limits solder spreading. Upper leg 38 of the U-shaped terminal 22 includes a contact arm 50 joined to beam 44 by U-shaped joint 40. The contact arm terminates in a contact portion 52 which is bowed downwardly through window 28 (Fig. 1) into opening 26 to present a rounded surface for engaging IC card 12. Contact arm 50 is narrower than U-shaped joint 40 whereby the U-shaped joint provides a measure of sturdiness and reliability for the terminal, while narrower contact arm 50 provides more flexibility or resiliency for the arm. Figure 3 shows how flanges 42a of base 42 of each terminal 22 are anchored within the overmolded plastic material of mounting bar 32 of housing 20. Contact arm 50 of the terminal also can be seen disposed within one of the grooves 34 in the top of the mounting bar. Finally, Figure 3 also shows that housing 20 has at least one mounting post 54 for insertion into a mounting hole 56 in printed circuit board 16. Figure 4 shows how contact 50 of one of the terminals 22 projects back over base 42 of the terminal and over mounting bar 32 of the housing within one of the grooves 34 in the top of the mounting bar. This locates the downwardly bowed contact portion 52 of the terminal above a respective one of the circuit traces 18 on the printed circuit board. Figure 5 shows IC card 12 about to be inserted into opening 26 in housing 20 of connector 10, in the direction of arrow "A". A mouth 58 of the opening is provided at the front edge of housing 20 for receiving the IC card. A plurality of circuit pads 60 are provided on the top surface of the card along a leading edge 62 thereof for engaging downwardly bowed contact portions 52 of terminals 22. Therefore, the terminals are effective to electrically connect circuit pads 60 on the IC card with circuit traces 18 (Fig. 4) on top planar surface 14 of printed circuit board 16. Figure 6 shows IC card 12 fully inserted in the direction of arrow "A" into opening 26 of housing 20 of connector 10. Contact pads 60 now can be seen in engagement with contact portions 52 of terminals 22. Finally, another feature of the invention is the provision of one or more securing tabs 64 (Fig. 1) which project outwardly from the sides of housing 20 for securement, as by soldering, to metal securing pads 66 on top planar surface 14 of printed circuit board 16. Figure 3 shows that securing tabs 64 are planar and include upwardly turned flanges 64a which are overmolded within housing 20 to anchor the securing tabs to the housing. These securing tabs can be soldered to securing pads 66 at the same time or during the same soldering process when surface mount sections 46 of terminals 22 are soldering to circuit traces 18 of the printed circuit board. It will be understood that the invention may be embodied in other specific forms without departing from the central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.

Claims: A surface mount electrical connector (10) for connecting an electronic component such as an IC card (12) on a planar surface of a printed circuit board (16) which includes circuit traces thereon, comprising: a dielectric housing (20) mounting a plurality of electrical terminals (22); wherein said housing (20) has a bottom surface (24) for mounting on the printed circuit board (16), an opening (26) for receiving the IC card (12), and a mounting bar (32) along one side of the opening (26); and wherein each terminal (22) includes a base (42) mounted on the mounting bar (32) of the housing (20), a beam (44) extending from the base (42) , and a contact arm (50) joined to the beam (44) at a U-shaped joint (40) and extending back over the beam (44) and terminating in a contact portion (52) at said opening (26) in the housing for electrical connection to the IC card (12), characterized in that the beam (44) includes a surface mount section (46) for electrical connection to a circuit trace on the printed circuit board (16). The surface mount electrical connector (10) of claim 1 wherein a window (28) in a top wall (30) of the housing (20) exposes the opening (26). The surface mount electrical connector (10) of claim 2 wherein the contact portion (52) is bowed downwardly through said window (28). The surface mount electrical connector (10) of one of claims 1 to 3, being a low profile surface mount electrical connector. The surface mount electrical connector (10) of one of claims 1 to 4 wherein the dielectric housing (20) is generally flat. The surface mount electrical connector (10) of one of claims 1 to 5 wherein the dielectric housing (20) is overmolded about the plurality of electrical terminals (22). The surface mount electrical connector (10) of one of claims 1 to 6 wherein the base (42) of each terminal (22) is overmolded in the mounting bar (32) of the housing (20). The surface mount electrical connector (10) of one of claims 1 to 7 wherein the electrical terminals (22) are stamped and formed. The surface mount electrical connector (10) of one of claims 1 to 8 wherein the surface mount section (46) is generally planar for electrical connection to a circuit trace on the planar surface (14) of the printed circuit board (16). The surface mount electrical connector (10) of one of claims 1 to 9 wherein said surface mount section (46) of each terminal (22) is wider than the beam (44) thereof. The surface mount electrical connector (10) of one of claims 1 to 10 wherein said base (42) of each terminal (22) is generally planar and includes flange portions (42a) formed out of the plane of the base (42) to anchor the base in the mounting bar (32) of the housing (20). The surface mount electrical connector (10) of one of claims 1 to 11 wherein said base (42) of each terminal (22) is generally coplanar with the bottom surface (24) of the housing (20). The surface mount electrical connector (10) of one of claims 1 to 12 wherein said beam (44) and surface mount section (46) of each terminal (22) are coplanar with the base (42) thereof and the bottom surface (24) of the housing (20). The surface mount electrical connector (10) of one of claims 1 to 13 wherein said mounting bar (32) of the housing (20) has an outer side (32a) defining an outside edge of the housing and an inner side (32b) defining an inside edge of the opening (26) in the housing (20). The surface mount electrical connector (10) of one of claims 1 to 14 wherein said beam (44), surface mount section (46) and U-shaped joint (40) of each terminal (22) are located outside the outer side (32a) of the mounting bar; the contact arm (50) extends over the mounting bar (32); and the contact portion (52) is located inside the inner side (32b) of the mounting bar (32). The surface mount electrical connector (10) of one of claims 1 to 15 wherein said mounting bar (32) of the housing (20) includes a top surface with a plurality of grooves (34) to accommodate the contact arms (50) of the terminals (22). The surface mount electrical connector (10) of one of claims 1 to 16 wherein said contact arm (50) of each terminal (22) is narrower than the U-shaped joint (40) thereof. The surface mount electrical connector (10) of one of claims 1 to 17 wherein said contact portion (52) of each terminal (22) is bowed toward the opening (26) to present a rounded surface for engaging the IC card (12). The surface mount electrical connector (10) of one of claims 1 to 18, including at least one securing tab (64) overmolded in the housing (20) remote from the terminals (22) and including a securing portion for connection to the printed circuit board (16).

Inventors: ZUIN GIANNI, ZUIN, GIANNI
Applicants: MOLEX INC, MOLEX INCORPORATED
Application year: 1999
Main classification: H01R12
IPC codes: H01R24, H01R12, H01R27