Patent Publication Number: US-6911613-B1

Title: Key switch and keyboard equipped with such key switch

Description:
FIELD OF THE INVENTION 
   The present invention relates to a key switch, particularly to a type of key switch that has integrated and sturdy construction to resist compressive and destructive impact from the outside. 
   BACKGROUND OF THE INVENTION 
   As shown in  FIG. 1 , U.S. Pat. No. 5,504,283 has disclosed a key switch  10  comprising a first link member  7  and a second link member  8  that are interlinked to each other and connected with a key top  5 , and a substrate  1 . However, the first link member  7  and the second link member  8  in the disclosure have one of their ends constructed in the shape of the letter “H”, which appears to be of a frail structure. Meanwhile, the structure adopted in the assembly of the first link member  7 , the second link member  8 , the key top  5  and the substrate  1  also appears to be weak, and may easily be broken or damaged by the compression of an outside force applied to the key switch  10 . 
   In view of the foregoing weakness in the prior art, the present inventor has come up with an innovative key switch to resist compressive and destructive force coming from outside. 
   SUMMARY OF THE INVENTION 
   It is the objective of this invention to provide a key switch of integrated and sturdy construction to resist compressive and destructive force from the outside. It is another objective of this invention to provide a key switch to prevent destruction of all components already assembled inside the key switch when the key top is pulled upwardly by an outside force. 
   It is yet another objective of this invention to provide a keyboard that adopts the present invention of the key switch in its application, that is connected to a desktop computer, or is built inside a notebook computer. 
   To achieve the above objectives, the present invention provides a key switch comprising: an outside frame in the shape of a hollow square, the frame having a protruded post at each of two ends of a first side thereof, the protruded post being capable of sliding in a slide slot on a key top, and a square-shaped hinge part at each of the two ends of a second side, the hinge part being hinged to a fixing slot on a bottom plate; an the inside frame is inter-hinged to the outside frame, forming a square shape, having a hinge rod at a middle section of the first side, the hinge rod being capable of sliding inside the slide slot on the bottom plate, and a square-shaped snap part at each of the two ends of the second side, the snap part being snapped and fastened in a snap slot on the key top; the key top has at least a slide slot and a snap slot; the bottom plate has at least a fixing slot and a slide slot. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above objects and advantages of the present invention will become more apparent with reference to the appended drawings wherein: 
       FIG. 1  is a schematic view of the prior art of the key switch; 
       FIG. 2  is an exploded view of the present invention of the key switch; 
       FIG. 3  is a lateral plan view of the present invention of key switch; 
       FIG. 4A  is a schematic view of the outside frame; 
       FIG. 4B  is a schematic view of the inside frame; 
       FIG. 5  is a schematic view of the bottom of the key top; 
       FIG. 6  is a schematic view of the bottom plate; 
       FIG. 7  is a first embodiment view of the keyboard equipped with the invention of key switch; and 
       FIG. 8  is a second embodiment view of the keyboard equipped with the invention of key switch. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 2  shows an exploded view of the present invention of key switch.  FIG. 3  shows a lateral plan view of the present invention of key switch. The invention of key switch  20  comprises, in order from top to bottom, a key top  201 , an outside frame  203 , an inside frame  205 , a flexible member  207 , a flexible circuit board  209  and a bottom plate  211 ; wherein the outside frame  203  and the inside frame  205  are inter-hinged to each other. The bottom plate  211  and the key top  201  respectively have slide slots  2111  and slide slots  2011  to hold the assembly of the outside frame  203  and the inside frame  205 , so that when the key top  201  is depressed or restored to its original position, the outside frame  203  and the inside frame  205  are capable of sliding inside the slide slots  2111  and the slide slots  2011 . The bottom plate  211  and the key top  201  respectively have fixing slots  2113  and snap slots  2013 , to respectively hold the outside frame  203  and the inside frame  205 . The key top  201  penetrates the inter-hinged outside frame  203  and inside frame  205  and reaches to the bottom of the key top  201 . 
   When the key top  201  is depressed, the flexible member  207  is driven by the downward force to come into contact with the flexible circuit board  209 . Since the flexible circuit board  209  is installed with a circuit contact point  2091 , the pressure and contact of the flexible member  207  cause electrical connection to the circuit contact point  2091 , thereby creating key-pressing signals. 
     FIG. 4A  shows a schematic view of the outside frame  203 , and  FIG. 4B  shows a schematic view of the inside frame  205 . The outside frame  203  and the inside frame  205  of the invention have the shape of roughly a square frame. Since the fours sides of the outside frame  203  and the inside frame  205  are joined together, forming an enclosed square frame, such an enclosed square structure is capable of withstanding a larger pressure without breaking or destroying the outside frame  203  and the inside frame  205 . The outside frame  203  has a first side  203 A, and a protruded post  2031  at each of two ends of the first side  203 A, the protruded post  2031  reaching into and capable of sliding within the interior of the slide slot  2011  of the key top  201 . The outside frame  203  has a second side  203 B, and a square-shaped hinge part  2033  at each of two ends of the second side  203 B, the hinge parts  2033  serving to be connected with fixing slots  2113  on the bottom plate  211 . Since the four sides of the hinge parts  2033  are joined to form a sturdy construction and resist unwanted outside force that may cause damage to the hinge parts  2033  and result in disengagement of the hinge parts  2033  from the fixing slots  2113  on the bottom plate  211 . 
   The inside frame  205  and the outside frame  203  are inter-hinged to each other. The inside frame  205  has a hinge rod  2051  installed at a middle section of the first side  205 A. The hinge rod  2051  is linked to the slide slot  2111  on the bottom plate  211 , capable of sliding inside the slide slot  2111 . The inside frame  205  has a second side  205 B, and a snap part  2053  installed at each of two ends of the second side  205 B. The snap part  2053  is shaped as a hollow square, and the snap part  2053  has a snap rod  2053   a  fastened to the snap slot  2013  on the key top  201 . 
   Furthermore, the outside frame  203  is hinged to the key top  201  on the protruded post  2031 , the inside frame  205  is hinged to the bottom plate  211  on the hinge rod  2051 , and the hinge part  2033  of the outside frame  203  is in contact with the bottom plate  211  on the cross rod  2033   a ; the present invention further makes an arched face of contact between the slide slot  2011  and the protruded post  2031 , an arched face of contact between the slide slot  2111  and the hinge rod  2051 , and an arched face of contact between the fixing slot  2113  and the cross rod  2033   a ; but there is no limitation on the shape of other faces not in contact. 
   Furthermore, the inside frame  205  is inter-hinged to the interior of the outside frame  203 , and the height of the inside frame  205  after they are hinged shall not be higher than the height of the outside frame  203 . 
     FIG. 5  shows a schematic view of the bottom of the key top  201 . On two sides of the bottom of the key top  201  are respectively installed with slide slots  2011  and snap slots  2013 . As described above, the slide slot  2011  is hinged to the protruded post  2031  of the outside frame  203 , and the snap slot  2013  used to fasten the snap rod  2053   a  of the inside frame  205 . The present invention places an emphasis on the key top  201  where an open slot  2011   a  is provided on the slide slot  2011 , the open slot  2011   a  forming a side wall for the slide slot  2011 . The open slot  2011   a  is designed to serve the following function. When the key top  201  is pulled up by an outside force, such as for the purpose of replacing a new key top, accidentally pulling on the key top  201  will result in destruction to the structure of the inside frame  205  and the outside frame  203 , since the key top  201  is structurally linked to move along with the outside frame  203  and the inside frame  205 , resulting in disintegration of the inside frame  205  and the outside frame  203 . The open slot  2011   a  provided on the slide slot  2011  is designed to avoid such disintegration, so that, when the key top  201  is pulled up by an outside force accidentally, the protruded post  2031  on the outside frame  203  is capable of escaping through the open slot  2011   a  and out of the slide slot  2011 , thereby avoiding destruction to the inter-hinged inside frame  205  and outside frame  203 . 
     FIG. 6  shows a schematic view of the bottom plate. The bottom plate  211  has a slide slot  2111  and fixing slots  2113 . As described above, the slide slot  2111  is hinged to the hinge rod  2051  of the inside frame  205 , and the fixing slots  2113  are hinged to the hinge parts  2033  of the outside frame  203 . An important characteristic of the present invention lies in openings  2115  on the bottom plate  211 , and two recesses  2035  provided at a middle section of the second side  203 B of the outside frame  203 . To assemble, the recesses  2035  are respectively pressed into the openings  2115 . The main function of the recesses  2035  and the openings  2115  after the assembly lies in that, the protruded post  2031  on the outside frame  203  is capable of moving simultaneously when the outside frame  203  is moving up and down, because of the positioning function of the recesses  2035  and the openings  2115 , the outside frame is capable of steadily moving up and down without wobbling left and right. The material of the bottom plate  211  is a flexible thin plate, or a thin metal plate. 
     FIG. 7  shows a keyboard including the first embodiment of the present invention of the key switch.  FIG. 8  shows a keyboard including the second embodiment of the present invention of the key switch. The keyboard  30  has at least one key switch  20 ; the keyboard  30  serves mainly as an input device for a desktop computer. The keyboard  40  has at least one key switch  20 ; the keyboard  40  serves mainly as an input device for a notebook computer. 
   It is to be understood that the foregoing description of the present invention should not be based to restrict the invention, and that all equivalent modifications and variations made without departing from the intent and import of the foregoing description should be included in the following claim.