Thanks to the progress in various technological fields, 3C products (Communication, Consumer electronics, and Computer products) have been constantly improved. For instance, the currently available computer systems now have quicker and quicker computing speed, and the central processing unit (CPU) or the microprocessor of a computer system performing the major computing function thereof has more powerful processing capability. However, the size of the CPU or microprocessor for the computer system does not increase along with the enhanced ability thereof, but is even reduced in some cases. That is, the density of the integrated circuits provided on the CPU or the microprocessor is obviously increased. Thus, heat produced by the CPU or the microprocessor during operation thereof also largely increases to adversely raise the surface temperature of the CPU or the microprocessor even to a level higher than 100° C.
To prevent the CPU or the microprocessor from being damaged or causing burnout of nearby elements due to the high temperature thereof, it is necessary to have some mechanism for timely removing the produced heat from the CPU or the microprocessor. Generally, such heat removing mechanism includes a thermal module having a base attached to a surface of a heat-producing element, such as the CPU, the microprocessor, a graphics chip, or a south and a north bridge chip, for absorbing the produced heat; and a heat pipe transferring the heat from the base to a plurality of radiating fins, which is extended through by the heat pipe, so that the produced heat is finally radiated from the radiating fins into ambient air. For the thermal module to stably mount to a mainboard of the computer system, a fastening device is usually needed to connect to the radiating fins extended through by the heat pipe, and a fastening element, such as a screw, is then downward extended through the fastening device to screw into the mainboard.
FIGS. 1A and 1B as well as FIGS. 1C and 1D showing a first and a second conventional manner, respectively, for fastening a thermal module to a mainboard. The thermal module includes a base 10, a heat pipe 11, a plurality of radiating fins 12, and a fastening device. The heat pipe 11 has an end attached to one side of the base 10, and another side of the base 10 is in contact with a heat-producing element, such as a CPU, a microprocessor, a graphics chip, a south bridge chip or a north bridge chip (not shown). Another end of the heat pipe 11 is extended through the radiating fins 12. The radiating fins 12 has a recess 121 formed on one side facing toward the fastening device 13 for receiving the fastening device 13 therein.
The fastening device 13 is made of a metal material, such as iron or copper, and has an end welded to a predetermined position on the radiating fins 12, so that a weld layer 15 is formed between one end of the fastening device 13 and the radiating fins 12 to permanently connect the fastening device 13 to the radiating fins 12. Another opposite end of the fastening device 13 is provided with a fastening hole 131, via which a fastening element 17 is downward extended to screw into a mainboard (not shown), so that the radiating fins 12 are firmly attached to the mainboard via the fastening device 13.
While the fastening device 13 enables fixed connection of the radiating fins 12 to the mainboard, the radiating fins 12 and the fastening device 13 welded thereto could not be separated from one another for reworking unless the weld layer 15 is completely removed from between the radiating fins 12 and the fastening device 13. However, when trying to remove the weld layer 15, it is almost inevitable to cause damages to the fastening device 13 and/or the radiating fins 12.
Further, when using the fastening device 13 to fasten the radiating fins 12 to the mainboard, the fastening device 13 is fixedly connected to the radiating fins 12 via the weld layer 15 and could not be freely adjusted to different positions to adapt to different designs. As a result, the conventional fastening device 13 has low applicability and is inconvenient for use and must be produced in different dimensions to match different design requirements, which inevitably increases the overall cost for mounting the thermal module to the mainboard.
In brief, the conventional fastening device for thermal module has the following disadvantages: (1) not allowing easy reworking; (2) increasing the cost for mounting the thermal module; and (3) not convenient for use.
It is therefore tried by the inventor to develop an improved fastening structure for thermal module, so as to eliminate the above drawbacks.