Patent Application
20090151897
1. Field of the Invention
The present invention relates to a heat dissipation device, more particularly to a heat dissipation device with bolts mounted thereon.
2. Description of Related Art
A conventional heat dissipation device, for dissipating heat generated by an electronic component on a printed circuit board, includes a base connecting with the electronic component, a plurality of fins formed on a top surface of the base and a plurality of bolts extending through the base for engaging with corresponding nuts to mounting the heat dissipation device to the printed circuit board. Each bolt includes a head and a thread end. A spring fits is encircling the bolt and is sandwiched between the head of the bolt and the base. Before the heat dissipation device mounted to the printed circuit board, the thread end of the bolt is screwed engaging in a corresponding screw thread hole defined in the base, and the springs loosely fit around the bolts. When transporting, the bolts drop from the base along the screw thread of the base because of vibration or other factors, which results in missing of the bolts from the heat dissipation device. This has adversely affected assembly quality of the heat dissipation device when the heat dissipation device is mounted to the printed circuit board.
What is needed, therefore, is a heat dissipation device which has bolts securely keeping with the heat dissipation device when transporting.
A heat dissipation device includes a base, a fin group mounted on a top surface of the base, and a plurality of fasteners secured on the base. Each fastener includes a bolt extending through the base, and an elastic sleeve engaging with the bolt under the base. The sleeve defines a hole and the hole has a configuration such that the sleeve securely clasp the bolt. The bolt extends through the base and engages in the hole of the sleeve.
Other advantages and novel features will become more apparent from the following detailed description of preferred embodiments when taken in conjunction with the accompanying drawings, in which:
Many aspects of the present embodiments can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Referring to
Referring to
Each heat pipe 30 is flattened and comprises a top surface (not shown) and a bottom surface (not shown) opposite to the top surface. Each heat pipe 30 has a straight evaporating portion 31 and two bent condensing portions 33 extending from opposite ends of the evaporating portion 31. When the heat pipes 30 are soldered in the base 10, the evaporating portions 31 are parallel and near to each other, and corresponding condensing portions 33 are spaced from each other. Thus, a distance between the corresponding condensing portions 33 is larger than that between the evaporating portions 33. The heat pipes 30 defines an X-shaped configuration in the base 10. [0015] The base 10 has a rectangular configuration and is made of metal such as aluminum or copper which has a high degree of heat conductivity. A length of the base 10 is larger than that of the fin group 20. The base 10 has a bottom surface (not labeled) and a top surface (not labeled) opposite to the bottom surface. The bottom surface of the base 10 intimately contacts with the electronic component. The bottom surface 217 of the fin group 20 thermally contacts with the top surface of the base 10. Two grooves 11 are defined at a top portion of the base 10 along a longitudinal direction of the base 10. The heat pipes 30 are received in the grooves 11. The top surface of the heat pipes 30 and the top surface of the base 10 are coplanar. Each groove 11 has a straight portion (not labeled) located at a centre of the base 10 and two bent portions (not labeled) extending from opposite ends of the straight portion and located at a front and rear portion of the base 10 respectively. The straight portions of the grooves 11 are adjoining to each other, and the bent portions at the front or rear portion of the base 10 are spaced from each other. Thus, the front and the rear portions of the base 10 form a substantially triangular protrusion portion 13 respectively. Two bulges 15 extend from the base 10 along a transverse direction of the base 10. The bulges 15 and the centre of the protrusion portions 13 define four counterbores 17, respectively. Each counterbore 17 defines a first through hole (not labeled) at a top portion of the base 10 and a smaller second through hole (not labeled) at a bottom portion of the base 10. Each fastener 40 is mounted in each counterbore 17.
Each fastener 40 comprises a bolt 41 received in the counterbore 17, a spring 43 encircling the bolt 41 and an elastic sleeve 45 engaged with the bolt 41. The bolt 41 has a circular head 411 and a shaft 413 extending downwardly from the head 411. The shaft 413 terminates with a screw end adapted for engaging in a nut (not shown) or a back plate (not shown) to mount the heat dissipation device on the printed circuit board. The spring 43 has an outer diameter smaller than a diameter of the head 411 and larger than a diameter of the shaft 413. Each sleeve 45 is made of elastic material such as rubber and comprises a cylindrical base 453 and a cylindrical mounting portion 451 with a through hole 457 extending through a centre of the base 453. The mounting portion 451 has a diameter larger than that of the second through hole of the counterbore 17. The through hole 457 has a diameter smaller than that of the shaft 413 of the bolt 41. In this embodiment, the mounting portion 451 has a circular cross section, and the through hole 457 is rectangular in the cross section. The shaft 413 of each bolt 41 extends the counterbore 17 and engages in the sleeve 45, thus, the bolt 41 is stably mounted on the base 10.
In assembly, the heat pipes 30 are soldered in the grooves 11 of the base 10, and the fin group 20 are soldered on the top surface of the base 10, and the fasteners 40 are secured on the base 10. A rear edge of the fin group 20 is aligned with a rear edge of the base 10. The fastener 40 located at the rear end of the base 10 is positioned in the cutout of the fin group 20. A front end of the fin group 20 is spaced from a front end of the base 10 and not covers the fastener 40 located at the front end of the base 10.
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments of the invention.
