Structure for preventing stacking connectors on boards from coming apart and electronic device

A structure is disclosed for preventing stacking connectors on a first and a second boards from coming apart that are fitted to each other. The first and second boards connected by said stacking connectors being fitted to each other are clamped by a clamping member. The clamping member is connected to surfaces on the first and second boards that connect to ground.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a structure for preventing stacking connectors on boards from coming apart, and to an electronic device having this structure.

2. Description of the Related Art

Heretofore, for preventing stacking connectors on boards from coming apart due to shocks, vibrations and the like, structures have been known in the art wherein stacking connectors are retained by device housing or by cushion members that are disposed at required locations inside the housing. Also, JP-A-2001-126810 discloses stacking connectors comprising a locking mechanism which prevents the stacking connectors that are fitted together from moving in a direction in which one comes off from the other, as a means to prevent dislodgement.

However, the former approach involves wasted space that is not used to mount parts therein owing to the structure that retains the stacking connectors. For example, when cushion members are used, space between the stacking connectors will be filled up only with the cushions. The latter approach, on the other hand, has the drawback that it is necessary to provide special stacking connectors and to make an extra connection to ground, as will be later described.

A foldable radio communications device such as a portable telephone can be constructed using stacking connectors with a flexible printed circuit board interposed between a board for a liquid crystal display and a board for a keyboard. In this case, a connection is also made to ground in order to prevent the flexible printed circuit board from acting as a floating metal substance to adversely affect the antenna characteristics. This connection to ground is typically made by soldering of the flexible printed circuit board, a conductive tape or the like. But these are not desirable from the standpoint of working costs and workability. The conductive tape also has the problem that it cannot be reused.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a structure which is capable of preventing stacking connectors on boards from coming apart, and also capable of making a connection to ground.

It is another object of the present invention to provide an electronic device having such a structure.

To this end, in accordance with the present invention, there is provided a structure for preventing stacking connectors on a first and a second boards from coming apart that are fitted to each other, wherein the first and second boards connected by the stacking connectors being fitted to each other are clamped by a clamping member, the clamping member being connected to surfaces on the first and second boards that connect to ground.

The present invention assures that the stacking connectors is prevented from coming apart with a simple structure, and also improves efficiency in mounting parts, workability, antenna characteristics, and resistance to electrostatic breakdown.

The clamping member may be a clip member made of a metal. The use of the clip member facilitates handling and enables its reuse.

The structure may further comprise a stop member for deterring the clamping member from dropping. In this case, the stop member may preferably be held by a stationary frame member.

A gap of a predetermined width may preferably be provided between the stop member, the frame member and the clamping member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will hereinafter be given of an embodiment in which the present invention is applied to a foldable portable telephone.

Referring first toFIG. 1, the general configuration of a foldable portable telephone that employs a fixing structure for stacking connectors according to the present invention is illustrated. The foldable portable telephone illustrated inFIG. 1mainly comprises a button manipulation section which includes front case12for accommodating board4for a keyboard and rear cover13, and a liquid crystal display section which includes front case14for accommodating board11for a liquid crystal display and rear cover15. Further, flexible printed circuit board1is arranged between board4for the keyboard and board11for the liquid crystal display. Flexible printed circuit board1is secured at one end to stacking connector2ato be fitted into stacking connector2bon board4for the keyboard, and at the other end to stacking connector2cto be fitted into stacking connector2don board11for the liquid crystal display. Stacking connectors2aand2care coupled together via a flexible strip member. Board4for the keyboard is electrically connected to sub-board7which is fixed to board4through frame8.

Next, referring toFIGS. 2 and 3, a structure will be described for preventing the stacking connectors that connect board1with board4, also shown inFIG. 1, from coming apart. After the terminals of a pair of stacking connectors2a,2bhave been fitted to each other, clip10is mounted to clamp both board4for the keyboard and flexible printed circuit board1(seeFIG. 4). Clip10is a conductive, resilient metal member and is generally U-shaped with upper and lower clamping portions each having a predetermined width, and a connecting portion which connects the clamping portions.

Frame8serves to fix sub-board7and is provided with stop member9in the form of a claw-like protrusion to prevent clip10from popping out or dropping therefrom. The stop member is configured such that when clip10slides toward stop member wall, a side end (closed end) of clip10is caused to abut against the stop member to prevent clip10from dropping. Provided between frame8and stop member9and clip10is gap16of a predetermined width which ensures that shocks and vibrations will not be transmitted to stacking connectors2a,2b, when an external force is exerted to the portable telephone or when the portable telephone is dropped. Thus, clip10will not slide or come off due to external forces, shocks, vibrations or the like.

Flexible printed circuit board1is further provided with surface3that connect to ground plane, in a region of the top surface thereof with which clip10comes into contact, and board4for the keyboard is likewise provided with surface6that connects to ground, in a region of the bottom surface thereof with which clip10comes into contact, thereby also making a connection to ground through mounting clip10.

Next, referring toFIG. 4, in conjunction withFIGS. 1 to 3, a procedure will be described for assembling the structure to prevent the stacking connectors from coming apart. First, stacking connector2aon flexible printed circuit board1is fitted into stacking connector2bon board4for the keyboard.FIG. 4represents a state in which stacking connectors2a,2bare fitted to each other. Then, clip10is attached to clamp both flexible printed circuit board1and board4for the keyboard, by using cutout5for positioning, cutout5being provided on board4.

Subsequently, after sub-board7, which is electrically connected to board4for the keyboard, is fixed to frame8, as illustrated inFIG. 1, frame8is brought into engagement with the top surface of stacking connector2aon board4for the keyboard. Thereafter, the other stacking connector2con flexible printed circuit board1is fitted into stacking connector2don board11for the liquid crystal display. These electrically connected boards are assembled into front cases12,14, and rear covers13,15are fitted on front cases12,14, respectively, thereby completing the assembling procedure.

As is apparent from the foregoing description, stacking connectors2a,2bcan be prevented from coming apart by clamping flexible printed circuit board1and board4for the keyboard with clip10. It is also possible to deter the stacking connectors from dropping and to improve the antenna characteristics and resistance to electrostatic breakdown by positively connecting surfaces3and6of flexible printed circuit board1and board4for the keyboard with conductive clip10.

Also, in addition to the ability to improve the workability, the configuration illustrated in the foregoing embodiment solves the problem of reusability, as compared with a conventional connection to ground which is made by soldering, conductive tape or the like. Furthermore, the configuration illustrated in the foregoing embodiment also makes it possible to improve efficiency in mounting parts because space for mounting parts is secured on the stacking connector by utilizing the frame.

Also, in the foregoing embodiment, a configuration is employed wherein cutout5is provided on one end of board4for the keyboard, in order to improve workability. However, board4for the keyboard may be provided with a recess into which clip10fits, or flexible printed circuit board1may be provided with a similar cutout, groove, or printed pattern. These may be omitted if it is recognized that the workability is not much affected, as a matter of course. In addition, the tip of the clip may be configured to fit into such a recess, groove or the like, to prevent drop or slide of the clip.

While the foregoing embodiment has been described by way of example in which a gap is provided between frame8and clip10, the width of the gap may be set depending on the device which employs a structure for preventing the stacking connectors from coming apart, and may be zero as required. Alternatively, a deformable spacer member, preferably made of a cushioning material, may be arranged between frame8and clip10.

While the foregoing description has been given of an embodiment in which the present invention is applied to a portable telephone, the present invention can be equally applied to electronic devices, including personal computers and PDA's (Personal Digital Assistant), which include a structure for connecting a plurality of boards (irrespective of the type of board) using stacking connectors. Also, in view of the features of the present invention, it can be said that the present invention is more preferably applicable to a fixing structure using stacking connectors to connect a flexible printed circuit board to other boards (irrespective of whether the boards are rigid or flexible).