Patent Publication Number: US-11387056-B2

Title: Key preloading structure and assembly method thereof

Description:
This application claims the benefit of People&#39;s Republic of China application Serial No. 201911315482.9, filed Dec. 19, 2019, the subject matter of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates in general to a key, and more particularly to a key preloading structure and an assembly method thereof. 
     Description of the Related Art 
     To assure the overall consistency, aesthetics and functional needs, the size of the keys is increased in some electronic products, such as mouse. Since the keys have a large size and are integrally formed in one piece with the housing, the pressed feel of the keys differs widely and is hard to assure, and problems such as dead zone and virtual press may easily arise when pressing the keys. 
     SUMMARY OF THE INVENTION 
     The invention is directed to a key preloading structure and an assembly method thereof. The set of keys preloads the set of switches with a force less than a triggering force for starting the set of switches. During the assembly process, the set of keys remains in contact with the set of switches and will not generate any extra clearance, hence resolving the virtual press problem which occurs when pressing the keys. 
     According to a first aspect of the present invention, a key preloading structure including a base, a set of switches and a set of keys is provided. The set of switches is arranged on the base. The set of keys has a rotating shaft and two actuators. The rotating shaft is assembled on the base. One end of each actuator is fixedly connected to the rotating shaft, and another end is disposed on the set of switches. Each of the actuators preloads the set of switches with a force less than a triggering force for starting the set of switches. 
     According to a second aspect of the present invention, a key assembly method used in a key preloading structure is provided. The key preloading structure includes a base, a set of switches and a set of keys. The set of keys has a rotating shaft and two actuators. The key assembly method includes the following steps. The rotating shaft is assembled on the base, wherein the rotation of the rotating shaft is restricted by a detachable component. One end of each actuator is temporarily connected to the rotating shaft, and another end is disposed on the set of switches, wherein each of the two actuators preloads the set of switches with a force less than a triggering force for starting the set of switches. One end of each actuator is fixedly connected to the rotating shaft, and the detachable component is detached. 
     The above and other aspects of the invention will become better understood with regard to the following detailed description of the preferred but non-limiting embodiment(s). The following description is made with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a mouse according to an embodiment of the present invention. 
         FIG. 2A  is an explosion diagram of a key preloading structure according to an embodiment of the present invention. 
         FIG. 2B  is a schematic 3D diagram of a key preloading structure according to an embodiment of the present invention. 
         FIG. 3  is a schematic diagram of a key assembly method according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Detailed descriptions of the invention are disclosed below with a number of embodiments. However, the disclosed embodiments are for explanatory and exemplary purposes only, not for limiting the scope of protection of the invention. Similar/identical designations are used to indicate similar/identical elements. Directional terms such as above, under, left, right, front or back are used in the following embodiments to indicate the directions of the accompanying drawings, not for limiting the present invention. 
     According to an embodiment of the present invention, a key preloading structure and an assembly method thereof used in a mouse are provided, for example. Refer to  FIG. 1, 2A and 2B .  FIG. 1  is a schematic diagram of a mouse  101  according to an embodiment of the present invention.  FIG. 2A  is an explosion diagram of a key preloading structure  100  according to an embodiment of the present invention.  FIG. 2B  is a schematic 3D diagram of a key preloading structure  100  according to an embodiment of the present invention. 
     The key preloading structure  100  includes a base  110 , a set of switches  112  and a set of keys  120 . The set of switches  112  is arranged on the base  110 . The set of keys  120  has a rotating shaft  121  and two actuators  122  (that is, the left key and the right key). The rotating shaft  121  is assembled on the base  110  (that is, the fixed frame  111  of the base  110 ). One end of each actuator  122  is fixedly connected to the rotating shaft  121 , and another end of each actuator  122  is disposed on the set of switches  112 . The two actuators  122  preload the set of switches  112  with a force W less than a triggering force for starting the set of switches  112 . The force W is mainly generated by the actuators  122  but can be changed to fit actual needs through the selection of material or the thickness of the actuators  122 . Besides, the key preloading structure  100  may further include a housing  102  (referring to  FIG. 1 ) disposed opposite to the base  110 . The housing  102  has an opening  104  in which the two actuators  122  are arranged. 
     Let the mouse  101  be used as an embodiment. A set of mechanical fretting switches  112  is disposed under the set of keys  120  of the mouse  101 . When a key (that is, an actuator  122 ) of the mouse  101  is pressed downwards, a metal reed  113  of the set of mechanical fretting switches  112  will trigger the contact underneath to complete a click operation. In an embodiment, the triggering force for moving the metal reed  113  of the set of switches  112  downwards is such as 50 g or above, but the invention is not limited thereto. 
     Moreover, the mouse  101  can be an optical mouse, and the housing  102  may further include a receiver (not illustrated) and a light source module (not illustrated) disposed therein. The light source module is arranged on the base  110 . When the receiver receives a light from the light source module, this indicates that the user operates the mouse to perform a click operation. In an embodiment, the force W preloaded on the metal reed  113  of the set of switches  112  by each actuator  122  is less than a triggering force (W&lt;50 g) and is such as in a range of 10 g-20 g, but the invention is not limited thereto. When the preloaded force W of each actuator  122  is less than the triggering force for moving the metal reed  113  of the set of switches  112  downwards, the metal reed  113  of the set of switches  112  will not contact the contact underneath, and the receiver will not receive the light from the light source module. This indicates that the user does not operate the mouse to perform a click operation. 
     In an embodiment, the set of switches  112  includes a set of force sensing elements or a set of thin-film switch elements, respectively configured for generating a pressing signal. The force sensing elements can be realized by mechanical, piezoelectric, capacitive or resistance inductive force sensors. The thin-film switch element includes an upper circuit board and a lower circuit board. When the user&#39;s finger presses the thin-film switch element, the contacts of the upper circuit board and the lower circuit board are pressed and become electrically connected. Conversely, when the user&#39;s finger is off the thin-film switch element, the contacts of the upper circuit board and the lower circuit board rebound and make the contacts of the upper circuit board and the lower circuit board break away. 
     Refer to  FIGS. 2A and 2B . One end of the two actuators  122  connected to the rotating shaft  121  has two shaft sleeves  125 , that is, the left shaft sleeve and the right shaft sleeve in which the rotating shaft  121  can be mounted. During the assembly process, firstly, the two ends of the rotating shaft  121  are temporarily mounted in the two shaft sleeves  125  of the actuators  122 ; then, a locking member  127 , such as a screw rod, passes through each of the shaft sleeves  125  to fix the shaft sleeves  125  on the rotating shaft  121 . In another embodiment, the shaft sleeves  125  can be fixed on the rotating shaft  121  using other method (engagement, adhering or clamping), such that the shaft sleeves  125  and the rotating shaft  121  are fixedly connected and can rotate synchronously. 
     Refer to  FIGS. 2A and 2B . The two actuators  122  have two protrusions  123  facing and correspondingly contacting the top surfaces of the set of switches  112  (or the metal reeds  113 ). That is, the two actuators  122  preload a force W on the set of switches  112  to provide a pressed feel and preloaded force. Therefore, the key preloading structure  100  of the present embodiment can resolve the conventional problems of the pressed feel of the keys differing widely and being hard to assure, and avoid dead zone and virtual press which may easily arise when pressing the keys. 
     Refer to  FIG. 2A and 2B . The rotating shaft  121  has a limiting piece  124  facing the base  110 . When the limiting piece  124  and a stopping plate  114  of the base  110  (that is, the fixed frame  111 ) contact each other, the two actuators  122  preload a force W on the set of switches  112 . Therefore, during the assembly process, the two actuators  122  can be positioned when the limiting piece  124  and the stopping plate  114  contact each other, such that the two actuators  122  and the set of switches  112  remain to be in contact with each other and will not generate extra clearance. 
     Refer to  FIG. 2B . When the two actuators  122  apply a force to start the set of switches  112 , the limiting piece  124  rotates relative to the rotating shaft  121  in a first direction S 1 . When the two actuators  122  removes the force W from the set of switches  112 , the limiting piece  124  contacts the stopping plate  114  and is restricted to rotate relative to the rotating shaft  121  in a second direction S 2  inverse to the first direction S 1 . 
     Refer to  FIGS. 2A and 2B . The key preloading structure  100  may further include a detachable component  115 , such as a screw or other component, configured to temporarily fix the limiting piece  124  on the stopping plate  114 , wherein the detachable component  115  is detached after the set of keys  120  is assembled on the base  110 . Therefore, during the assembly process, the limiting piece  124  is positioned and cannot rotate in the first direction  51  or the second direction S 2 , such that the two actuators  122  and the set of switches  112  remain to be in contact with each other and will not generate extra clearance. Then, the detachable component  115  is detached after the assembly of the set of keys  120  is completed. 
     In an embodiment, the detachable component  115  can pass through the bottom of the base  110  to enter the hole  116  to temporarily fix the limiting piece  124  on the stopping plate  114 . The detachable component  115  can be realized by a screw or an insertion piece. In the present embodiment, the detachable component  115  does not have to pass through the bottom of the base  110  to enter the hole  116 , that is, the detachable component  115  can enter the hole  116  from other angle or position. 
     Refer to  FIGS. 2A, 2B and 3 .  FIG. 3  is a schematic diagram of a key assembly method according to an embodiment of the present invention. The key assembly method for assembling the set of keys  120  on the base  110  includes steps S 110 -S 130 . In step S 110 , the rotating shaft  121  is assembled on the base  110 , and the rotation of the rotating shaft  121  is restricted by a detachable component  115 . In step S 120 , one end of each actuator  122  is temporarily connected to the rotating shaft  121 , and another end is disposed on the set of switches  112 , wherein each of the two extended actuators  122  preloads the set of switches  112  with a force W less than a triggering force for starting the set of switches  112 . That is, during the assembly process, the two actuators  122  can be positioned when the limiting piece  124  and the stopping plate  114  contact each other, such that the two actuators  122  and the set of switches  112  remain to be in contact with each other and will not generate extra clearance. 
     In step S 130 , one end of each actuator  122  is fixedly connected to the rotating shaft  121 , and the detachable component  115  is detached. That is, during the assembly process, firstly, the two ends of the rotating shaft  121  are mounted in the two shaft sleeves  125  of the actuator  122 ; then, a locking member  127 , such as a screw rod, passes through each of the shaft sleeves  125  to fix the shaft sleeves  125  on the rotating shaft  121 . 
     According to a key preloading structure and an assembly method thereof disclosed in above embodiments of the present invention, the set of keys preloads the set of switches with a force less than a triggering force, such that during the assembly process, the set of keys and the set of switches remain to be in contact with each other and will not generate extra clearance, hence resolving the problem of virtual press which may easily arise during the process when pressing the keys. Therefore, the key preloading structure and the assembly method thereof of the present invention can improve the user&#39;s pressed feel of the key, and further can easily start the key. That is, the pressing force for starting the key (the pressing force +the preloaded force the triggering force) is relatively decreased, and the user will be less burdened with key pressing over a long duration of use. 
     While the invention has been described by way of example and in terms of the preferred embodiment(s), it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.