Heat dissipating device having improved fastening structure

A fastening structure provided by the present invention is used to fastening a heat dissipating device with a printed circuit board in which a plurality of holes is formed. The fastening structure has a back plate disposed underneath the printed circuit board and a plurality of fitting columns, wherein the back plate is perforated with a plurality of holes and each of the fitting columns has an elongate hollow tube and an insertion member projecting from a periphery of one end of the hollow tube. The hollow tube has a threaded internal sidewall and the insertion member has a shape conformal to the respective holes at which the fitting columns are fixed to the back plate.

BACKGROUND OF THE INVENTION

The present invention relates to a fastening structure of a heat sink, and more particular, to a structure to prevent loose or displacement of a heat sink.

The development of information technology has continuously improved the designs and devices in the computer related industry. The information processed by the related products such as interface cards and central process units (CPU) involved with logic operation becomes larger and larger. Consequently, the operation speeds are faster and faster. The increasing operation speeds results in the elevated temperature during operation. To reduce the heat generated by the high-power devices such as Intel P4 processor or AMD K8 processor, a heat dissipating device with a large volume has been commonly adapted in the industry. The large volume of the heat dissipating inevitably increases the overall weight of the products, such that a higher standard for fastening or mounting the heat dissipating device is demanded.

Taiwanese Patent Application No. 90211070 has disclosed an improvement of a fitting structure of a CPU heat sink. The CPU heat sink is sandwiched between the motherboard and the CPU by fastening screws to prevent the heat sink from loosening away from the CPU due to inadvertent impact. However, this type of heat dissipating device requires a supporting board and a threaded column with a specific design, such that the applicability is very limited.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a heat dissipating device with an improved fastening structure. The fastening structure includes a plurality of through holes such that the heat dissipating device can be attached to the heat dissipating device on various types and sizes of motherboards.

The present invention further provides a heat dissipating device that includes an improved fastening structure. The fastening structure uses fitting columns inserted through holes formed in a back plate and ensures that no relative rotation occurs between fitting plate and the fitting columns, such that the heat dissipating device is stably secured to the back plate.

The fastening structure provided by the present invention is used to fastening a heat dissipating device with a printed circuit board in which a plurality of holes is formed. The fastening structure comprises a back plate disposed underneath the printed circuit board and a plurality of fitting columns, wherein the back plate is perforated with a plurality of holes and each of the fitting columns includes an elongate hollow tube and an insertion member projecting from a periphery of one end of the hollow tube. The hollow tube has a threaded internal sidewall and the insertion member has a shape conformal to the respective holes at which the fitting columns are fixed to the back plate.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2show the exploded view and perspective view of a fastening structure used for fitting a heat sink to a heat generating device. The fastening structure includes a back plate10and a plurality of fitting columns20.

The back plate10is fabricated from metal, plastic or other materials. The back plate10is placed underneath a motherboard of a computer. In this embodiment, the back plate10is substantially rectangular. The back plate10includes two elongate slots13formed along two elongate sides thereof and two T-shape slots13form at two transverse sides between the elongate sides. Between the T-shape slots13and the transverse sides, the back plate10further includes a plurality of through holes12. The through holes12are hexagonal, rectangular, circular, triangular or other polygonal according to specific requirement.

Preferably, the fitting columns20are fabricated from metal materials. Each of the fitting columns20includes an elongate tube24which has a threaded internal surface and an insertion member21projecting from the periphery of a lower end of the elongate tube24. The elongate tube24is hollow and has two opening ends. The insertion member21includes a groove22recessed from a periphery thereof. The insertion member21is configured conformal to the through holes12formed in the back plate10.

Each of the fitting columns20further comprises an open washer23to be inserted into the groove22of the insertion member21. Therefore, when the insertion members21are disposed in the though holes12, the washers23hold the majority part of the fitting columns20over the back plate10, while the attachment between the fitting columns20and the back plate10can be reinforced by screw members threaded into the lower ends of the fitting columns20.

FIGS. 3to5shows the application of the fastening structure as described above to a heat dissipating device30which is to be mounted on a heat generating device41on a printed circuit board40. As shown, the printed circuit board40is sandwiched between the heat dissipating device30and the back plate10. The printed circuit board40is perforated with at least two holes42. The holes42are aligned with two through holes12formed along transverse sides of the back plate10allowing the fitting columns20fixed in the through holes12to penetrate through. The heat dissipating device30includes a frame31, a thermal conductive block32, a bracket33and a heat sink34. The frame31is perforated with a central aperture312for accommodating the heat generating device30therein while being placed on the printed circuit board40. Similar to the back plate10, the frame31is substantially rectangular and has two transverse sides perforated with a plurality of through holes311. The through holes311are aligned with the holes42formed in the printed circuit board40and the through holes12formed in the back plate10. Therefore, the elongate tubes24can extend through to secure the printed circuit board40between the frame31and the back plate10by screw members37threaded into the upper ends of the fitting columns20. Preferably, resilient members36such as springs are inserted between the heads of the screw members37and the printed circuit board40.

The thermal conductive block32is placed on top of the heat generating device41within the frame31. The thermal conductive block32is preferably formed of materials with good conductivity such as aluminum or copper, for example. As shown, the top surface of the thermal conductive block32is recessed to form a channel321extending across the top surface along an elongate direction of the thermal conductive block32. The bracket33includes a central elongate member and two T-shape bracket members331extending from two opposing ends of the central elongate member. The central elongate member can be inserted into the channel321and is sufficiently long such that when the central elongate member is inserted in the channel321, the T-shape bracket members331protrude from two longitudinal sides of the thermal conductive block32. By overlaying the transverse sides of the frame31on top of the T-shape bracket members331and fastening the frame31to the printed circuit board41and the back plate10, the thermal conductive block32is securely mounted to the heat generating device41.

As shown inFIG. 3, the fastening structure may further comprises a shock absorbing member35such as a layer of foam or sponge between the back plate10and the printed circuit board40. The cross section of the heat sink34is substantially rectangular. The lower surface of the heat sink34is recessed to form a channel conformal to the cross section of the thermal conductive block32, such that the heat sink34can be place across the thermal conductive block32. The lower corners of two lateral sides of the heat sink34are preferably removed, such that the lower portion of the heat sink34can be inserted into the frame31.

As shown inFIGS. 6-7, the fitting columns20may further comprise bottom lids25as shown in FIG.6. The outer diameter of the bottom lids25is larger than the diameter of the holes12formed in the back plate, such that a blocking effect can be achieved. Similarly, as shown inFIG. 7, a top lid may also be inserted on the insertion members21to achieve the holding effect similar to the washers23as shown in FIG.1.

The heat dissipating device and the fastening structure provided by the present invention has at least the following advantages.1. Various types of through holes are formed in the back plate, such that the fastening structure is operative to secure the heat dissipating device to printed circuit boards with various configuration and sizes.2. The fitting columns are fixed to the back plate to avoid a relative rotation between the fitting columns and the back plate. Therefore, the heat dissipating device is stably attached to the printed circuit board.3. The printed circuit board and the heat generating device is sandwiched between the heat dissipating device and the back plate, such that damage of the printed circuit board and the heat generating device caused by impact is minimized.

This disclosure provides exemplary embodiments of the present invention. The scope of this disclosure is not limited by these exemplary embodiments. Numerous variations, whether explicitly provided for by the specification or implied by the specification, such as variations in shape, structure, dimension, type of material or manufacturing process may be implemented by one of skill in the art in view of this disclosure.