1. Field of the Invention
The present invention generally relates to sliding mechanisms, and more particularly, to a sliding mechanism used for a portable electronic device with two or more housings.
2. Discussion of the Related Art
Sliding mechanisms are widely used in portable electronic devices, such as mobile phones and personal digital assistants (PDAs). Referring to FIG. 8, a typical sliding mechanism generally includes a first plate 50, a second plate 60, and a linkage module (not labeled) configured for linking the first plate 50 and the second plate 60. The first plate 50 and the second plate 60 are substantially rectangular in shape. The linkage module includes two fixing members 52, two shafts 62, two rails 65, and two springs 67. The fixing members 52 are fixed to the center portion of the second plate 60 and aligned along a same line. Each fixing member 52 defines a through hole (not labeled) therein. The shafts 62 are fixed adjacent to opposite sides of the first plate 50 respectively. An end of each rail 65 is slidably inserted through the through hole of the fixing members 52, and an opposite end of each rail 65 is rotatably connected to the shafts 62. The rails 65 are rotatable about an axis of the corresponding shafts 62. Each spring 67 is sleeved on the corresponding rails 65 between the fixing members 52 and the shafts 62.
In use, in a starting position, the second plate 60 is at an end of the second plate 60, and the second plate 60 is open or closed relative to the first plate 50. When the second plate 60 of sliding mechanism 100 is pushed by an external force, the second plate 60 is moved relative to the first plate 50. As such, the fixing members 52 are moved together with the second plate 60. At this time, the rails 65 slide relative to the through hole of the fixing members 52, and rotate about the axes of the shafts 62. A distance between the fixing members 52 and the shafts 62 is decreased. Thus, the spring 67 becomes compressed and accumulates potential energy until the second plate 60 reaches the middle of the first plate 50. When the second plate 60 is pushed across the middle of the first plate 50, the external force is removed. The potential energy of the springs 67 is released and pushes the second plate 60 to slide further, until the second plate 60 is closed or open relative to the first plate 50.
However, the sliding mechanism causes several problems. Firstly, since the springs 67 are disposed above the first plate 50 and the second plate 60, when the sliding mechanism is employed in an electronic device and the second plate 60 slides relative to the first plate 50, the springs 67 may be blocked by other components of the electronic device. Thus, the sliding mechanism cannot be normally operated, and the springs 67 may be damaged. Secondly, two rails 65 require a relatively large space for movement. Thirdly, the first plate 50 and the second plate 60 are disposed on a same side of the rails 65 and the spring 67. A width of the first plate 50 should be larger than that of the second plate 60 so that the shafts 62 can be fixed to the first plate 50. Therefore, the sliding mechanism occupies a relatively large volume. Fourthly, the linkage module of the sliding mechanism includes so many components, causing high production costs.
What is needed, therefore, is a sliding mechanism which overcomes the above-described shortcomings.