Abstract:
A multiple key assembly ( 100 ) includes a multiple key including a central key ( 1 ) and four key segments ( 2 ) separated from each other, a base member ( 4 ) having a base ( 42 ), a circular platform ( 44 ), a plurality of connecting parts ( 46 ) flexibly connecting the circular platform with the base and a PCB ( 6 ). A plurality of contacts ( 49 ) is provided on bottoms of the circular platform and the connecting parts, and the PCB provides a plurality of contact pads ( 62 ) corresponding in position to the contacts on the base member. During assembly, the multiple key is first mounted on the base member and then both are secured to the PCB with the plurality of contacts of the base member suspended above the corresponding contact pads on the printed circuit board. If desired, an elastic spacer ( 3 ) and/or a key sheath ( 5 ) can be included.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to data input devices for electronic devices and, more particularly, to multiple key assemblies for electronic devices.  
         BACKGROUND OF THE INVENTION  
         [0002]    Nowadays, there is a considerable consumer demand for electronic devices having a small form factor, and there is also a competing consumer demand for such electronic devices that include more and more features. This competing demand generally translates into greater data processing and display capabilities, which typically requires greater real estate in the electronic device. With regard to display capabilities, it is considered desirable to provide an electronic device with as large a display screen as practical. However, increasing the size or viewable area of a display screen associated with a small form factor electronic device leaves little room for data entry from a conventional keypad matrix, such as a keypad matrix shown in U.S. Pat. No. D 416,024. It is not practical to continue reducing the size and/or the spacing of the buttons that form a conventional keypad matrix arrangement.  
           [0003]    To overcome the foregoing difficulties, U.S. Pat. No. 6,157,323 discloses a multiple key assembly to integrate a plurality of key segments together, resulting in a keypad matrix occupying less room. A similar multiple key assembly is also described in U.S. Pat. No. 6,441,753. Both the multiple key assemblies can rotate around a pivot so that a user can select and depress a specific key segment to electrically connect with a printed circuit board (PCB) while the other key segments remain disconnected. However, because the key segments of the above multiple assemblies are integral, when a key segment is depressed, the other key segments maybe also be depressed or influenced and thus an incorrect manipulation frequently occurs. In addition, the sense of depressing the key segment is not satisfactory due to the bad elasticity of the multiple key assemblies.  
           [0004]    Therefore, an improved multiple key assembly of an electronic device is desired to overcome the disadvantages of the prior art.  
         SUMMARY OF THE INVENTION  
         [0005]    A main object of the present invention is to provide a multiple key assembly for an electronic device which can avoid incorrect manipulation thereof.  
           [0006]    Another object of the present invention is to provide a multiple key assembly for an electronic device which provides a good sense of manipulation.  
           [0007]    To achieve the above objects, a multiple key assembly of an electronic device comprises a central key, four key segments for surrounding the central key, a base member and a printed circuit board. The central key and the four key segments are separated from each other. The base member has an outer portion called a base, a central portion called a circular platform, and a plurality of connecting parts flexibly connecting the circular platform with the base. A plurality of contacts is provided on bottoms of the circular platform and the connecting parts. The printed circuit board provides a plurality of contact pads corresponding in position to the contacts on the base member. During assembly, the central key and the four key segments are first mounted on the base member and then the base member with the keys is secured to the printed circuit board with the plurality of contacts of the base member suspended above the corresponding contact pads on the printed circuit board. When manipulating the keys, one of the keys is pressed to make the circular platform or the corresponding connecting part move downwardly until the contact corresponding in position to the key contacts with the corresponding contact pad on the printed circuit board and a circuit is closed. When the key is released, the depressed key will recover to its original position under the elastic force exerted by the circular platform of the base member. If desired, an elastic spacer can be mounted on the base member to increase the elastic force exerted against the four key segments. Of course, a key sheath also can be included to cover the multiple key assembly.  
           [0008]    Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of a preferred embodiment thereof when taken in conjunction with the accompanying drawings, wherein: 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is an exploded, perspective view of a multiple key assembly of an electronic device in accordance with a first embodiment of the present invention viewed from a top aspect;  
         [0010]    [0010]FIG. 2 is an exploded, perspective view of the multiple key assembly of FIG. 1, viewed from a bottom aspect;  
         [0011]    [0011]FIG. 3 is a perspective view of the assembled multiple key assembly of FIG. 1 viewed from a top aspect;  
         [0012]    [0012]FIG. 4 is a perspective view of the assembled multiple key assembly of FIG. 3 viewed from a top aspect; and  
         [0013]    [0013]FIG. 5 is an exploded, perspective view of a multiple key assembly of an electronic device in accordance with a second embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0014]    With reference now to the drawings in detail, FIGS. 1 and 2 show a multiple key assembly  100  for an electronic device in accordance with a first embodiment of the present invention. The multiple key assembly  100  comprises a central key  1 , a plurality of key segments  2 , an elastic spacer  3 , a base member  4 , a key sheath  5 , a printed circuit board (PCB)  6  and a plurality of bolts  7 .  
         [0015]    The central key  1  has the shape of a flat cylinder and define a blind hole  12  in its bottom. The key segments  2  are separated from each other and constitute a ring-shaped configuration. Each key segment  2  is substantially a hollow cover with a cavity defined in its bottom; said cavity is divided into two engaging holes  24  by a central wall  22  thereof. Two gaps  26  are formed in the bottom of each key segment  2  adjacent to two ends thereof and respectively communicate with the two engaging holes  24 . The central key  1  and the key segments  2  constitute a multiple key (not labeled). The elastic spacer  3  has a ring  32  and a plurality of pairs of elastic legs  34  extending therefrom. Each pair of elastic legs  34  comprises a first leg  36  and a second leg  38 , which are positioned and shaped to engage with the gaps  26  of a single key segment  2 .  
         [0016]    The base member  4  has an outer portion, called a base  42 , a central portion, called a circular platform  44 , which is formed in a middle of the base  42  and a plurality of connecting parts  46  connecting the base  42  with the circular platform  44 . A protrusion  442  extends upwardly from the circular platform  44 . A bottom surface (not labeled) of the circular platform  44  is coplanar with bottom surfaces (not labeled) of the connecting parts  46  and is spaced above a bottom surface (not labeled) of the base  42 , thus a shallow concavity  41  is formed beneath the circular platform  44  and the connecting parts  46 . Also, a plurality of spaces  48  is defined between the connecting parts  46 . Each connecting part  46  has a stepped configuration and forms three steps having different heights, i.e., a lowest seat  466 , an interior step  468 , and a highest step  467  between the seat  466  and the interior step  468 . A slot  462  is formed in a middle of the step  467  of the connecting part  46  to divide the step  467  into two engaging tabs  464 . A plurality of contacts  49  respectively extends from the bottom surfaces of the circular platform  44  and the connecting parts  46 . In the present invention, said contacts  49  are preferably positioned at a middle of said bottom surfaces. A plurality of tab holes  426  and pin holes  424  are provided in the base  42 .  
         [0017]    The key sheath  5  has a round opening  52  to receive the central key  1  and the key segments  2  therein. A plurality of pins  58  and locating tabs  562  extend from a bottom surface of the key sheath  5 . Said locating tabs  562  each having a receiving hole  56  in a middle thereof and a height thereof is substantially identical with a thickness of the base  42 . On a top surface of the key sheath  5  corresponding in position to the receiving holes  56  there are a plurality of glue-receiving openings  59  which communicate with the receiving holes  56 , respectively. The PCB  6  also has a plurality of bolt holes  64  and pin holes  66  defined therein. A plurality of contact pads  62  is provided on the PCB  6  corresponding in position to the contacts  49  of the base member  4 .  
         [0018]    During assembly, first, the elastic spacer  3  is placed on the base member  4  so that the ring  32  is positioned on the seats  466  of the connecting parts  46  and the plurality of pairs of elastic legs  34  are respectively received in the corresponding gaps  26 . A top surface of the ring  32  on the seats  466  now is coplanar with a top surface of the interior steps  468 , thus ensuring the key segments  2  can be stably mounted thereon. Then, the key segments  2  are respectively assembled on the corresponding connecting parts  46  of the base member  4 . Accordingly, the engaging tabs  464  are received in the corresponding engaging holes  24  and the central walls  22  are inserted into the corresponding slots  462 . Also, each pair of the elastic legs  34  are engaged with the two gaps  26  of the corresponding key segment  2 . In a third step, the central key  1  is assembled on the circular platform  44  with the protrusion  442  engaging with the blind hole  12  and all the key segments  2  being arranged around the central key  1 . Thus, assembly of a multiple key subassembly  200  is finished.  
         [0019]    To assemble the multiple key subassembly  200  to an electronic device, the locating tabs  562  and the pins  58  of the key sheath  5  are passed through the corresponding tab holes  426  and pin holes  424  of the base member  4 , while the central key  1  and the key segments  2  extend through the round opening  52  of the key sheath  5 . Bottom surfaces of the locating tabs  562  are then abutted against a top surface of the PCB  6  at positions corresponding bolt holes  64  of the PCB  6 , and the exposed portions of the pins  58  threaded through the pin holes  424  are further extended through the pin holes  66  of the PCB  6 , while the axes of the corresponding receiving holes  56 , tab holes  426  and bolt holes  64  coincide with each other. At this point, the contacts  49  of the base member  4  are suspended above the corresponding contact pads  62  of the PCB  6 . Then the plurality of bolts  7  is extended through the corresponding bolt holes  64  and into the corresponding receiving holes  56 . The bolts  7  are fixedly engaged in the receiving holes  56  by a glue dripping through the glue-receiving openings  59  of the key sheath  5  into the receiving holes  56 . Thus a whole assembly of the multiple key assembly  100  is attained, as shown in FIGS. 3 and 4. It is easily understood that the pins  58  can also be fixed in the pin holes  424  and  66  by glue. Further, the central key  1  and the key segments  2  can be fixed to the base member  4  using the glue.  
         [0020]    When manipulating the multiple key of the multiple key assembly  100 , a key segment  2  or a central key  1  is pressed downwardly. If a key segment  2  is pressed, the corresponding elastic legs  34  and the corresponding connecting part  46  downwardly move until the contact  49  on the connecting part  46  contacts with the corresponding contact pad  62  and a circuit is closed. When the key segment  2  is released, it recovers to its original position under the elastic force exerted by the base member  4  and the elastic spacer  3 . If a central key  1  is pressed downwardly, the circular platform  44  downwardly moves until the contact  49  on the underside of the circular platform  44  contacts the corresponding contact pad  62  on the PCB  6  and the circuit is closed. When the central key  1  is released, it recovers to its original position under the elastic force exerted by the base member  4 .  
         [0021]    According to another embodiment of the present invention, the elastic spacer member  3  can be omitted from the multiple key assembly  100  to form a multiple key assembly  101 , as shown in FIG. 5. In this embodiment, the base member  4 ′ is modified to make the seats  466 ′ of the connecting parts  46 ′ coplanar with the interior steps  48  so as to stably mount the key segments  2  directly thereon without the help of the ring  32  of the elastic spacer  3 . Obviously, the multiple key subassembly  200  can be directly assembled on the PCB  6  by other convention connection methods, and thus the key sheath  5  can also be omitted.  
         [0022]    The central key  1  and the key segments  2  are separated from each other, so it is easy to distinguish them from each other when manipulating the multiple key assembly  100  or  101 , and to thus avoid wrongly depressing the key segments  2  or the central key  1 . In addition, because there is an enough space  48  between every two key segments  2  so that a depressed key segment  2  will not overly influence the adjacent key segments  2 , unwanted electrical connections between other key segments  2  and the PCB  6  are avoided. Furthermore, because of the elastic connection between the circular platform  44  and the base  42  through the plurality of connecting parts  46 , the sense of manipulating the multiple key assembly  100  or  101  becomes more comfortable and a depressed key segment  2  or depressed central key  1  recovers more quickly. Of course, using the elastic spacer  3  can strengthen the above effects.  
         [0023]    It will be apparent that many changes and modifications of the several features described herein may be made with departing from the spirit and scope of the invention. It is therefore apparent that the foregoing description is by way of illustration of the invention rather than limitation of the invention.