Patent Publication Number: US-2013233685-A1

Title: Press key

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a press key, more particularly to a press key including a magnetic restoring device. 
     2. Description of the Related Art 
     A press key can be used in a computer keyboard or a telephone keyboard. As shown in  FIGS. 1 and 2 , a conventional press key includes a keycap  1 , a bordering member  11 , a contact  2 , a restoring device  3 , and a base unit  4  that has a substrate  41  and a circuit module  411  formed on the substrate  41 . 
     The bordering member  11  is connected to the base unit  4 . The keycap  1  is spaced apart and extends outwardly from the bordering member  11 . The keycap  1  and the base unit  4  cooperatively define a space  10  therebetween. 
     The restoring device  3  is disposed in the space  10 , and includes an elastic member  31  and two levers  32  that are pivotally connected to each other. The elastic member  31  is connected to the keycap  1  and is made of rubber in a form of a bowl-shape. The elastic member  31  may be replaced by a restoring spring. The two levers  32  constitute a scissors-type linkage assembly and are connected between the base unit  4  and the keycap  1 . The contact  2  extends from the bowl-shaped elastic member  31 . When an external force is applied to press the keycap  1  toward the base unit  4 , the elastic member  31  is deformed so that the contact  2  is moved to contact the circuit module  411  to produce a signal (see  FIG. 2 ). When the external force is released, the deformed elastic member  31  returns to its original state due to its restoring force, thereby moving the two levers  32 , the contact  2  and the keycap  1  away from the base unit  4  (see  FIG. 1 ). 
     However, in order to achieve the state-restoring function of the restoring device  3 , the elastic member  31  should be formed to have a sufficient volume to provide enough restoring force to move the keycap  1 , the levers  32  and the contact  2  away from the base unit  4 . In order to meet the volume requirement of the elastic member  31 , the conventional press key usually cannot satisfy the trend toward miniaturization of electronic devices. Moreover, elastic fatigue problem of the elastic member  31  is likely to occur after a long period of service time. 
     SUMMARY OF THE INVENTION 
     Therefore, an object of the present invention is to provide a press key that can overcome the aforesaid drawbacks associated with the prior art. 
     Accordingly, a press key of this invention comprises: 
     a base unit; 
     a keycap movable with respect to the base unit; and 
     a magnetic restoring device including a first magnetic member connected to the keycap and disposed between the base unit and the keycap, and a second magnetic member disposed on the base unit, the first and second magnetic member producing a repulsive force therebetween to move the keycap away from the base unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the pre sent invention will become apparent in the following detailed description of the preferred embodiments of the invention, with reference to the accompanying drawings, in which: 
         FIG. 1  is a cross-sectional view of a conventional press key; 
         FIG. 2  is a cross-sectional view illustrating the press key of  FIG. 1  in a pressed state; 
         FIG. 3  is a cross-sectional view of the first preferred embodiment of a press key according to this invention; 
         FIG. 4  is a cross-sectional view illustrating the press key of  FIG. 3  in a pressed state; 
         FIG. 5  is a cross-sectional view of the second preferred embodiment of a press key according to this invention; and 
         FIG. 6  is a cross-sectional view illustrating the press key of  FIG. 5  in a pressed state. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Before the present invention is described in greater detail with reference to the accompanying preferred embodiments, it should be noted herein that like elements are denoted by the same reference numerals throughout the disclosure. 
     Referring to  FIGS. 3 and 4 , the first preferred embodiment of a press key according to this invention includes a keycap  5 , a bordering member  51 , a contact  6 , a magnetic restoring device  7  and a base unit  8 , and is adapted to be used in a computer keyboard or a telephone keyboard. The base unit  8  includes a substrate  81  and a circuit module  811  that is formed on the substrate  81  and that is capable of generating an electrical signal. 
     The bordering member  51  extends upwardly from the base unit  8 . The keycap  5  is movable with respect to the base unit  8 . In this embodiment, the keycap  5  is movably connected to the base unit  8 . For convenient and stable pressing operation, the keycap  5  is preferably cap-shaped and extends outwardly from the bordering member  51  in a normal state ( FIG. 3 ). 
     The contact  6  extends from the keycap  5  and is disposed in a space  50  between the keycap  50  and the base unit  8 . When the keycap  5  is pressed, the contact  6  is moved to contact the circuit module  811  of the base unit  8  to produce the electrical signal ( FIG. 4 ). In this embodiment, the circuit module  811  is a membrane circuit board, but is not limited thereto. For example, a printed circuit board having touch switches may also be used. In this embodiment, the contact  6  and the keycap  5  are formed in one-piece. 
     The magnetic restoring device  7  includes first and second magnetic members  71 ,  72 , and two levers  73 . The first magnetic member  71  is connected to the keycap  5  and is disposed in the space  50  between the base unit  8  and the keycap  5 . The second magnetic member  72  is disposed on a lower surface of the substrate  81  of the base unit  8  in a position corresponding to that of the first magnetic member  71 . The two levers  73  are pivotally connected to each other to constitute a scissors-type linkage assembly that is connected to the base unit  8  and the keycap  5 . Since the scissors type-linkage assembly is well-known in the relevant art, a detailed description thereof is omitted herein for the sake of brevity. 
     The first and second magnetic members  71 ,  72  have the same polarity, and thus, a repulsive force is formed between the first and second magnetic members  71 ,  72 , to move the keycap  5  along with the contact  6  away from the base unit  8 , thereby rendering the contact  6  to not contact the circuit module  811  (see  FIG. 3 ). As shown in  FIG. 4 , when an external force is applied to press the keycap  5  toward the base unit  8 , the contact  6  is also moved to contact the circuit module  811  to produce the electrical signal. After the external force is released, the keycap  5  and the contact  6  are moved to the original position ( FIG. 3 ) due to the repulsive force between the first and second magnetic members  71 ,  72 . 
     In the first preferred embodiment, the first magnetic member  71  is a permanent magnet, and the second magnetic member  72  is an electromagnet that is electrically connected to the base unit  8  and that has spiral coils  9 . By applying electricity to the second magnetic member  72  from the base unit  8 , the second magnetic member  72  can produce the same polarity as that of the first magnetic member  71 , thereby forming the repulsive force. When no power is supplied to the press key, no repulsive force is produced, and the keycap  5  moves toward the base unit  8  and stays at the position shown in  FIG. 4 . Therefore, the total thickness of the press key could be reduced, which is beneficial for storage of a product having the press key of this invention. 
     Alternatively, each of the first and second magnetic members  71 ,  72  may be the permanent magnet, the electromagnet, or any other article that can produce magnetism. 
     Because the magnetic members  71 ,  72  are used as the position restoring device, the volume requirement and the elastic fatigue problem for the conventional elastic member  31  could be eliminated in this invention. Thus, the sizes, thickness, and materials of the keycap  5  and the contact  6  are not limited, and can be adjusted to meet the requirement of cost reduction. In addition, when pressing the keycap  5 , it is only necessary to overcome the repulsive force between the first and second magnetic members  71 ,  72 , and thus, pressing of the keycap  5  is more effortless as compared to the prior art. 
       FIGS. 5 and 6  show the second preferred embodiment of a press key according to this invention. The second preferred embodiment differs from the first preferred embodiment in that: (1) the scissors-type linkage assembly (i.e., the two levers  73 ) are dispensed with; (2) the bordering member  51  extends from the base unit  8  to be disposed above the base unit  8  and has a bent end portion  511  that is bent toward the keycap  5 ; and (3) the keycap  5  has a cap body  521  and a flange portion  522 . The flange portion  522  extends outwardly and annularly from an end portion of the cap body  521 , and is movably disposed between the base unit  8  and the bent end portion  511 . With the bent end portion  511  and the flange portion  522 , the keycap  5  can be restricted in position between the base unit  8  and the bent end portion  511  of the bordering member  51  without the scissors-type linkage assembly, thereby simplifying the structure and reducing production costs of the press key. 
     While the present invention has been described in connection with what are considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.