Electronic Card With Sheet Metal and Overmolded Plastic Frame Parts

Electronic cards are inserted into slots of electronic devices such as computers to transfer information between them. One type of electronic card, sometimes referred to as a PC or IC card, includes a sheet metal cover. The cover includes top and bottom sheet metal cover halves which have overlapping sides that are welded together. These parts of the electronic card are sold to companies that make custom circuit boards and that assemble the card parts. Many companies do not have welding equipment. A newer approach is to form the cover halves with sheet metal plate parts for EMI (electromagnetic) shielding at the top and bottom of the card, and to overmold plastic around the edges of the sheet metal. In a sectional view, the plastic overmolding includes a top column at the top cover half and a bottom column at the bottom cover half, with the columns having abutting surfaces that can be sonically welded together. Sonic welding equipment is more readily available and is often preferred to welding equipment. The presence of plastic abutting surfaces that are to be sonically welded, can result in the absence of sheet metal at the sides of the card. Such sheet metal at the side has been useful to provide a grounding surface that can be engaged by a contact of the computer to discharge static electricity. Also, such sheet metal has been used to electrically connect the sheet metal plates at the top and bottom of the card. An electronic card of a type that includes sheet metal plate parts at the top and bottom for providing EMI protection thereat, but with plastic overmolding at the edge portions to enable sonic welding to join the cover halves, but which provided grounding regions at the opposite sides of the card for discharging static electricity from the top and bottom sheet metal plate parts, would be of value.

In accordance with one embodiment of the present invention, an electronic card is provided of the type that has sheet metal top and bottom plate parts but plastic edge portions that can be sonically welded together, which have grounding regions at the sides in a simple card construction. The bottom sheet metal plate part has an integral tab that projects outwardly through the plastic material to the outside of the card at its side grounding region and which extends upwardly therefrom, to provide a surface that can be brushed against to ground the card. The top sheet metal plate part has an integral top ear that extends through the plastic thereat to the outside of the card and which extends downwardly and lies in contact with the tab.

At the grounding region, the plastic of the lower cover half includes a chimney that extends upwardly and immediately outside the plastic of the top cover half. The tab which extends upwardly along the outside of the chimney, has a top tab portion that is bent around the top of the chimney and that extends downwardly, so contact between the tab and ear of the bottom and top cover halves, occurs in a protected area.

Where side shielding is required for the electronic card, a tab extends upwardly from the edge of the lower sheet metal plate part. The tab extends within a plastic column of the lower cover half to the top thereof. An ear of sheet metal extends down from the edge of the sheet metal at the upper cover part. The ear extends down along a plastic column of the upper cover part, with the top of the tab and bottom of the ear engaging each other.

Where connection of the top and bottom sheet metal plate parts is required, this can be accomplished by a spring that lies in a hole of the plastic columns in the lower and upper cover halves, where the holes extend through to the sheet metal plate parts.

The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.

FIG. 1 is a front and top isometric view of an electronic card constructed in accordance with one embodiment of the present invention, and showing, in phantom lines, an electronic device that receives the card.

FIG. 2 is a partial enlarged view of the card of FIG. 1, showing the grounding region thereof.

FIG. 3 is a sectional view taken on line 3--3 of FIG. 2.

FIG. 4 is a sectional view taken on line 4--4 of FIG. 2.

FIG. 5 is an exploded isometric view of a portion of the card of FIG. 1, showing the top and bottom cover halves and a portion of the circuit board and front connector thereof.

FIG. 6 is an exploded isometric view of only the sheet metal portions of the top and bottom cover halves of FIG. 5.

FIG. 7 is a sectional view of a portion of an electronic card constructed in accordance with another embodiment of the invention.

FIG. 1 illustrates an electronic card 10 of the present invention, which is designed to be inserted in a forward direction F into a slot 12 of a laptop computer or other electronic device 14. The electronic card includes a circuit board 20 that usually (but not always) carries electronic components (integrated circuits, resistors, etc.) and which has traces that connect to contact 22 of a front connector 24 of the card. The circuit board is protected from physical damage and EMI (electromagnetic interference) by a cover assembly 30 that includes top and bottom cover halves 32, 34. The card has front and rear ends 40, 42 and opposite sides 44, 46. A grounding region 50, 52 lies at each side, where a grounding contact 54 of the electronic device can engage the card to discharge any static electricity that is built up on the card and to ground the sheet metal of the cover. It is noted that the rear end 42 of the card may be closed, or may include an I/O (input-output connector) that enables connection of the electronic device to external equipment such as a modem, another computer, etc.

As shown in FIG. 2, the top and bottom cover halves 32, 34 include pieces of sheet metal or sheet metal portions 60, 62 that have plate-like parts 64, 66. The plate-like parts 64, 66 cover areas above and below the circuit board to protect it from EMI. The upper and lower cover halves also include plastic, or polymer frame parts 70, 72 that are overmolded around edge portions 74, 76 of the sheet metal plate-like parts 64, 66.

As shown in FIG. 4, the upper polymer frame part 70 forms a column 80 that extends downwardly from the sheet metal plate part edge portion 74. Similarly, the lower polymer frame part 72 forms an upwardly-extending column 82 that extends upwardly from the lower sheet metal edge portion 76. The columns form abutting plastic joint surface 84, 86 that can be easily joined by sonic welding. In sonic welding, a pair of sound passing members are pressed, one against the bottom of the lower cover half and the other against the top of the upper cover half, the member pressing against the plastic overmolding frame portions. Sonic energy is transmitted between the sound-passing members to sonically weld at the surfaces 84, 86. This joining technique is preferred in many cases, because of the low cost equipment and ease of use.

Static electricity sometimes builds up on the sheet metal plate parts 64, 66, and should be discharged when the card is inserted into a slot in the electronic device. FIG. 3 shows a cross section of the card cover at the grounding region 50 where static electricity can be discharged. At the grounding region 50, the sheet metal piece 62 of the lower cover half is provided with a tab 90 that is integral with the plate-like portion 66. The tab has a lower part 92 that extends through the plastic to the extreme outside of the cover, and the tab has an exposed tab part 94 that extends upwardly along the outside of the cover. The exposed tab part 94 wipes across a grounding contact of the electronic device into which the card is inserted to discharge static buildup. The tab includes a free end portion 96 that is bent and that has a downwardly-extending end 98 for engaging the sheet metal of the upper cover half.

The sheet metal piece 60 of the upper cover half includes an ear 100 with a top ear part 102 that extends through the plastic to the outside of the upper polymer frame part 70 and that extends downward therealong so the bottom 104 of the ear is positioned to engage the end 98 of the tab. This construction results in the top and bottom plate-like parts 64, 66 being electrically connected together, and with an exposed tab part 94 at the side of the frame which can be readily grounded by a contact of the electronic device that receives the card.

Applicant supports the exposed tab portion 94 and the free end portion 96 by providing the polymer bottom frame part 72 with a chimney 110. The chimney extends upwardly along the outer surface 112 of the polymer upper frame part 70. The free end portion 96 of the tab is bent around the top of the chimney and engages the top ear 100.

The chimney 110 lies only at the grounding region 50. As shown in FIG. 1, much of the length of the card from its front end, has a groove 120 for receiving a key of the electrical device 14 that assures that the card is not inserted upside down. FIG. 4 shows the cross section along this region. FIG. 1 shows that, rearward of the grounding regions 50, 52, there is no groove. FIG. 4 shows that where there is no groove 120, each of the columns 80, 82 of the cover halves include column parts 122, 124. The parts 122, 124 form additional areas of the junction surface 84, 86 where the cover halves are sonically welded together. The chimneys 110 of FIG. 3 (and at the other side) serve not only to support the exposed tab portions 94, but also can be used to align the top and bottom cover halves during assembly.

FIG. 6 shows the shape of the top and bottom sheet metal portions or pieces 60, 62 that each includes a plate-like sheet metal part 64, 66. It is noted that the edge portions 74, 76 include short fingers 140, 142 that project into the plastic to help anchor the plastic to the sheet metal. The shapes of the tabs 90 and ears 100 can also be seen.

FIG. 5 shows the cover separated, and shows a portion of the front connector 24 and of the circuit board 20 that lies between the cover halves. In some cases, where the top and bottom plate-like sheet metal parts 64, 66 are not reliably connected at grounding regions, a clip or spring can be used to connect the top and bottom sheet metal plate parts. FIG. 5 shows a tapered coil spring 150 which is used to connect the sheet metal parts 64, 66. The plastic frame parts 70, 72 of the cover halves are provided with holes 152, 154. When the spring is compressed, its lower end engages the sheet metal plate-like part 66 of the lower cover half and the sheet metal plate-like part 64 of the upper cover half. Although springs are known for electrically connecting upper and lower sheet metal parts, the placement of the spring 150 of the present invention, minimizes the space occupied by the spring and any guard around it, by placing the holes in the plastic frame parts. The upper portion 156 of the spring is tapered, so it can readily fit into the hole 154 when the cover halves are brought together.

In some applications, where high bit rates are transmitted so that the leading and trailing edges of pulses have high frequency components, shielding may be necessary around the sides of the card. FIG. 7 shows a construction wherein sheet metal pieces or portions 60A, 62A of the cover halves 32A 34A, are respectively provided with tabs 160 and ears 162 that form side shielding for the card. The tabs extend upwardly and the ears 162 extend downwardly, with at least one of them and preferably both of them projecting beyond the interface 164 where joined surface 84, 86 of the columns 80, 82 abut one another and can be sonically welded together. Preferably, an opening 170 is provided in at least one of the joined surfaces, so the top of the tab 160 can flex.

While terms such as "top", "bottom", etc. have been used to describe the relative positions of the parts, it should be understood that the card can be used in any orientation with respect to the Earth.

Thus, the invention provides an electronic card with a cover that has sheet metal plate parts at at least the top and bottom and plastic overmolded frame parts at the edges of the sheet metal to enable sonic welding, which provides improved grounding and shielding. At grounding regions at one and preferably both opposite sides of the card, a tab extending from one of the covers such as the lower one, extends to the outside of the card but is backed by a plastic frame part. The bottom plastic frame part can include an upstanding chimney that extends upward of and against a downwardly-extending plastic column of the upper frame part, with a tab of the lower sheet metal portion extending through the lower frame part and along the chimney, and with the top of the tab being bent around the chimney. The upper cover half includes a sheet metal ear that extends downwardly along the outside of the upper column and directly engages the bent-around upper portion of the tab. Where continuous sheet metal EMI protection is required at the sides of the card, this can be accomplished by upstanding sheet metal tabs in the bottom cover half and downwardly-extending sheet metal ears on the upper cover half, which extend within the columns of the plastic frame parts and which engage one another. Where the top and bottom sheet metal portions must be separately electrically connected, this can be accomplished by a spring that extends through holes in the plastic frame parts of the upper and lower cover halves to contact the sheet metal plate parts, to save space.

Athough particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.