Memory Card Assembly Having Improved Means for Grounding Printed Wiring Board and Method of Use

1. Field of the Invention

The present invention relates to electrical connectors and more particularly to memory card assemblies.

2. Brief Description of Prior Developments

In printed wiring board and memory card assemblies, a printed wiring board is conventionally fixed at its rear edge to an elongated receptacle which is pivotally connected to a frame in which the printed wiring board rests. Above and below the frame there are metallic cover plates. It is necessary that the printed wiring board be grounded to each of these plates. To accomplish this grounding, a pair of small springs are conventionally soldered to the printed wiring board. Because of the small size of these springs and the difficulty in handling them, this spring soldering process is expensive and time consuming. A need, therefore, exists for an improved means of grounding the printed wiring board in memory card assemblies.

In the present invention, a printed wiring board is interposed between upper and lower opposed cover plates. An electrical battery is also positioned between these cover plates in a recess in the printed wiring board. The battery is disc-shaped and has a negative contact area on one of its planar surfaces and a positive contact area on its curved peripheral surface. A positive terminal extends from the printed wiring board to contact the peripheral positive electrode on the battery. A negative terminal is attached adjacent the front edge of the printed wiring board. This negative terminal has an upper section which extends to contact the top cover plate. The negative electrode also has a lower end which extends downwardly to contact the lower cover plate and then extends horizontally to contact the negative planar contact area on the battery.

The printed wiring board and memory card assembly of the present invention is further described with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of the printed wiring board and memory card assembly of the present invention.

FIG. 2 is an exploded view of the assembly shown in FIG. 1.

FIG. 3 is a perspective view similar to FIG. 1 in which the cover plates have been removed.

FIG. 4 is a top plan view of the assembly shown in FIG. 3 in which the cover plates have been removed.

FIG. 5 is a cross sectional view through line V--V in FIG. 1 and FIG. 6 is a detailed view of the area within circle 6 in FIG. 1.

FIG. 6 is a cross sectional view similar to FIG. 5 except the position of a battery is shown;

FIG. 7 is an enlarged view of the area in circle VII in FIG. 2; and

FIG. 8 is an enlarged view of the area in circle VII in FIG. 2 in which the position of a battery is shown.

Referring to the drawings, the printed wiring board and memory card assembly of the present invention includes a metallic upper cover plate 10, a metallic lower cover plate 12 between which there is positioned a printed wiring board shown generally at numeral 14. This printed wiring board has lateral edges 16 and 18, a front edge 20 and a rear edge 22 which is fixed to an elongated receptacle 24 by means of solder tails as at 26. As is conventional, on its reverse side the receptacle engages a header (not shown). The printed wiring board includes a first major recess 28 which has a transverse side 30 and a longitudinal side 32. It also includes a second minor recess 34 adjacent the major recess which has a transverse side 36 and a longitudinal side 38. A positive terminal 39 is fixed at its one end to the transverse edge of the major recess and extends into the recess to contact a battery when one is positioned there. A metallic negative terminal is shown generally at numeral 40 and includes an upper first section 42, a lower second section 44 and a medial attachment area 46 at which it is fixed by soldering to a grounding pad on the printed wiring board adjacent the front edge of the printed wiring board, generally, and more particularly adjacent the transverse side of the minor recess. The lower section of the negative terminal in particular includes a vertical section 48 which extends downwardly to a terminal edge 50 which then extends laterally in horizontal section 52 to a terminal edge 54. The structure continues in upwardly angled section 56 to apex 58 to a downwardly angled section 60. These upwardly and downwardly angled sections are divided in two prongs 62 and 64 which terminate in horizontal sections respectively at 66 and 68.

Referring particularly to FIG. 6, the battery 70 has a planar upper side 71, a planar lower side 72 having a negative electrode, a peripheral edge 74 having a positive electrode 74. As is conventional, there is an insulative layer 75 on the lower side of the upper cover above the battery. When the battery is inserted into the assembly, the apex 58 on the negative terminal is in contact with the planar side negative electrode and the positive terminal is in contact with the peripheral positive electrode. A preferred battery for use in this assembly would be a PANASONIC CR 2025 3 volt lithium battery. It will be understood that for this type of battery the negative terminal will be positioned on the bottom planar side of the battery while the positive terminal will be positioned on the curved peripheral edge of the battery as well as on the planar top side.

The plastic frame is shown generally at numeral 76 and includes lateral bars 78 and 80 and a transverse front bar 82. Projections 84 and 86 on opposite ends of the receptacle engage recesses as at 88 in the lateral bars of the frame to allow for engagement between the receptacle and printed wiring board and the frame. The battery may be retained in battery retaining member 90 which includes a front section 92. The battery retaining member is engageable with a battery receiving structure 94 which includes a transverse bar 96 and a longitudinal bar 98. When the battery retaining member is engaged in this manner, its front section 92 is an integral section of the transverse front bar 82 of the frame. Referring again particularly to FIGS. 2 and 8, it will be seen that a slide lock 100 fits into groove 102 in the battery retaining member and adjacent clip 104 to lock the battery retaining member in position in the battery receiving structure. Another clip 105 locks the battery retaining member into lateral bar 78.

Again, it will seen referring to the drawings generally, that the frame also includes reinforcing bar 106 and that the lateral and front bars include a top face 108 and an outer peripheral ridge 110. In its assembled configuration, the printed wiring board is spaced vertically above the top face inwardly from this peripheral ridge. On the top cover plate there are a number of clips as at 112 and 114 which engage recesses as at 116 and 118 on the peripheral ridge to attach the top cover plate to the frame. Similarly, there are clips as at 120 and 122 on the lower cover plate which engage other recesses (not shown) to attach the lower cover plate to the frame.

It will be appreciated that since it uses a single grounding element which also services as a battery terminal, the printed wiring board in a memory card assembly of the present invention may be efficiently and cost effectively produced.

While the present invention has been described in connection with the preferred embodiments of the various figures, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiment for performing the same function of the present invention without deviating therefrom. Therefore, the present invention should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims.