1. Field of the Invention
The present invention relates to a sliding opening and closing device and a portable terminal having the same. More specifically, it relates to a sliding opening and closing device, of which a slide plate is automatically opened from or closed into a main plate if it is applied with a force only initially, and relates to a portable terminal wherein the sliding opening and closing device is installed so that a sub body can be opened from and closed into a main body by a sliding operation.
2. Description of the Related Art
Generally, a sliding opening and closing device means a part that connects two items with each other and makes the items to be slidable for each other. The sliding opening and closing device is used in various fields, e.g., home electronics such as a refrigerator, office machines such as a duplicator, computer equipment such as a notebook computer monitor and an LCD monitor, and telecommunications equipment such as a cellular phone, a PCS phone and a PDA, etc.
Recently, as the use of portable wireless terminals becomes universalized, as well as the simple intrinsic function of the wireless communication, additional functions are also being required for the opening and closing operation in order to satisfy the taste of each user.
According to this request, portable terminals have been developed from general bar-type terminals to flip-type terminals, to flip-up-type terminals and to folder-type terminals, etc. Currently, the folder-type terminals are predominantly used.
That is because the folder-type terminals have sufficient special room enough to employ a wide LCD module as a display device and have a superior portability to other terminals since they are foldable in half.
Meanwhile, a sliding-type terminal has been known. It can be equipped with a display device having a wide LCD module with similar size of that of a folder-type terminal. Also, it can be conducive to minimization of a terminal.
In case of the sliding-type terminal, a sub body as a cover is opened and closed on a main body in a sliding operation. It has an additional advantage of being opened and closed in a new operation while maintaining the advantages of the existing folder-type terminal.
As a kind of such sliding-type terminal, a sliding-type portable wireless terminal has been filed by the applicant, Himac Corporation, under the Korean Utility Model Application No. 2003-0000136.
The terminal disclosed in the above application comprises a guide means for guiding a sub body onto a main body and at least one elastic means for changing direction of pressure in a direction of opening or in a direction of closing based on a certain sliding position of the sub body between the sub body and the main body. Also, when the sub body operates a complete opening or a complete closing by the elastic means, it can maintain the maximum opening position or the maximum closing position without a stopper. As the elastic means, a torsion spring is employed. One end of the torsion spring is fixed to the main body and the other end is fixed to the sub body.
In case of such terminal, as the sub body moves, the torsion spring rotates and supplies rotating force to the sub body. During the action, the torsion spring gets strained and relaxed widely. For this reason, torsion springs with wide motion but less elasticity power were used. In order to complement the insufficient elastic force, two torsion springs were arranged.
However, in case of the above terminal, although two torsion springs were arranged, the elasticity power was not sufficient because of the characteristic of the torsion spring. Furthermore, since the torsion springs loosened widely, they aged easily due to fatigue with repeated actions and lost their normal function early.