Grounding a heat sink in thermal contact with an electronic component using a grounding spring having multiple-jointed spring fingers
First Claim
1. A heat sink grounding spring, comprising:
- a base comprising a conductive material having a generally planar portion, wherein an opening is formed in the generally planar portion of the base through which a heat sink and a module are to be placed in thermal contact with each other, wherein the opening has four sides defining a generally rectangular shape, wherein the generally planar portion of the base is configured to contact at least a portion of a peripheral surface of the heat sink;
a multiple-jointed spring finger comprising a conductive material extending from the generally planar portion of the base to form a generally Z-shaped spring element, wherein the multiple-jointed spring finger is repeated as two or more multiple-jointed spring fingers disposed along each of the opening'"'"'s four sides so that eight or more of the multiple-jointed spring fingers extend from the generally planar portion of the base, wherein the multiple-jointed spring finger is configured so that movement of a concave tip thereof is substantially limited to a direction perpendicular to the generally planar portion of the base as the multiple-jointed spring finger is compressed toward the generally planar portion of the base, and wherein the concave tip is to receive in ball-in-socket fashion at least a portion of a solder pad on the surface of a printed circuit board on which the module is mounted.
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Accused Products
Abstract
A grounding spring for electromagnetic interference (EMI) suppression is interposed between a heat sink and a printed circuit board (PCB). The grounding spring comprises a conductive material having an opening formed at its base through which the heat sink makes thermal contact with an electronic module mounted on the PCB. The base makes electrical contact with a peripheral surface of the heat sink, and multiple-jointed spring fingers extend from the base to make electrical contact with conductive pads on the PCB. During compression, the movement of each spring finger'"'"'s tip is substantially limited to the z-axis. Accordingly, the final installed location of the tip can be precisely controlled even when the grounding spring must accommodate a wide variety of installed heights of the heat sink relative to the PCB. Preferably, the spring fingers terminate with a concave tip that is less susceptible to sliding off the conductive pads.
39 Citations
15 Claims
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1. A heat sink grounding spring, comprising:
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a base comprising a conductive material having a generally planar portion, wherein an opening is formed in the generally planar portion of the base through which a heat sink and a module are to be placed in thermal contact with each other, wherein the opening has four sides defining a generally rectangular shape, wherein the generally planar portion of the base is configured to contact at least a portion of a peripheral surface of the heat sink; a multiple-jointed spring finger comprising a conductive material extending from the generally planar portion of the base to form a generally Z-shaped spring element, wherein the multiple-jointed spring finger is repeated as two or more multiple-jointed spring fingers disposed along each of the opening'"'"'s four sides so that eight or more of the multiple-jointed spring fingers extend from the generally planar portion of the base, wherein the multiple-jointed spring finger is configured so that movement of a concave tip thereof is substantially limited to a direction perpendicular to the generally planar portion of the base as the multiple-jointed spring finger is compressed toward the generally planar portion of the base, and wherein the concave tip is to receive in ball-in-socket fashion at least a portion of a solder pad on the surface of a printed circuit board on which the module is mounted. - View Dependent Claims (2, 3, 4)
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5. A circuit card assembly, comprising:
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a printed circuit board having an electronic module mounted on a surface thereof; a heat sink disposed over the surface of the printed circuit board and in thermal contact with the module; a grounding spring comprising a conductive material having an opening formed in a generally planar base portion thereof through which the heat sink and the module are in thermal contact with each other, wherein the base portion makes electrical contact with at least a portion of a peripheral surface of the heat sink, and wherein a plurality of multiple-jointed spring fingers extend from the base portion to form a plurality of generally Z-shaped spring elements that make electrical contact with conductive pads on the surface of the printed circuit board, wherein each of the multiple-jointed spring fingers in configured so that movement of a concave tip thereof is substantially limited to a z-axis as the multiple-jointed spring finger is compressed toward the base portion of the grounding spring, and wherein the concave tip makes electrical contact with one of the conductive pads by receiving in ball-in-socket fashion at least a portion of a conductive pad on the surface of the printed circuit board. - View Dependent Claims (6, 7, 8, 9, 10, 11)
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12. A heat sink grounding spring, comprising:
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a base comprising a conductive material having a generally planar portion, wherein an opening is formed in the generally planar portion of the base through which a heat sink and a module are to be placed in thermal contact with each other, wherein the opening has four sides defining a generally rectangular shape, wherein the generally planar portion of the base is configured to contact at least a portion of a peripheral surface of the heat sink; a multiple-jointed spring finger comprising a conductive material extending from the generally planar portion of the base to form a generally Z-shaped spring element, wherein the multiple-jointed spring finger is configured so that movement of a concave tip thereof is substantially limited to a direction perpendicular to the generally planar portion of the base as the multiple-jointed spring finger is compressed toward the generally planar portion of the base, and wherein the concave tip is to receive in ball-in-socket fashion at least a portion of a solder pad on the surface of a printed circuit board on which the module is mounted. - View Dependent Claims (13, 14, 15)
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Specification