Patent Publication Number: US-11024475-B2

Title: Waterproof switch

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. National Stage of International Patent Application No. PCT/EP2017/057213 filed on Mar. 27, 2017, which is hereby incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     The disclosure relates to a switch provided with sealing means and a button structure comprising such a switch. 
     BACKGROUND 
     Waterproof electronic devices are becoming increasingly popular. The interior of such a device has to be protected against ingress of water in order to avoid damaging the electronic components of the device. By adding waterproofing elements to every aperture or gap in an electronic device, the assembly becomes more complex and more space consuming. 
     An existing waterproof switch apparatus comprises a push button, a switch, and an elastic sheet arranged between the push button and the switch in order to protect the interior of an electronic device from ingress of water. The elastic sheet is provided with at least one an aperture such that the sheet can be press-fitted onto a shaft portion of the push-button. This solution allows the waterproofing element, i.e. the elastic sheet, to be arranged partially around the push-button such that the space consumption and the thickness of the switch apparatus is reduced. 
     However, an increased number of components and assembly steps results in large tolerance stack up between a push-button and its corresponding switch, impairing the tactile qualities of the push-button. The tactile qualities of the push-button are also impaired when placing the waterproofing element between push-button and switch. Also, the added friction caused by the waterproofing element increases the risk of the push-button jamming. 
     Accordingly, it would be desirable to be able to provide a waterproof switch apparatus that addresses at least some of the problems identified above. 
     SUMMARY 
     It is an object to provide an improved switch which is waterproof, and which has reduced components. 
     It is another object to provide a button structure including the improved switch. 
     The foregoing and other objects are achieved by the features of the independent claims. Further implementation forms are apparent from the dependent claims, the description, and the figures. 
     According to a first aspect, there is provided a switch comprising a switch body, having a first switch body section and a second switch body section, a switch contact configured to be arranged in a slot in the first switch body section, a switch contact cover configured to cover the slot, and a sealing means configured to cover a circumference of the second switch body section. Thus switch manufacture, as well as subsequent mounting into an electronic device, is facilitated due to a reduction in components. Further the tactile qualities of the push button which is corresponding to the switch is improved. 
     In a first possible implementation form of the first aspect, the first switch body section has a larger cross-section than the second switch body section. This facilitates fitting the sealing means onto only a section of the switch body, since the sealing means is naturally delimited by a step caused by the change in cross-section. 
     In a second possible implementation form of the first aspect, the switch contact comprises a dome. 
     In a third possible implementation form of the first aspect, the sealing means comprises a gasket. 
     In a fourth possible implementation form of the first aspect, the sealing means comprises a circumferentially extending ridge. 
     In a fifth possible implementation form of the first aspect, the sealing means is molded onto the switch body by means of injection molding. 
     According to a second aspect, there is provided a button structure for an electronic device, the electronic device comprising a housing having an external surface and an internal surface, the surfaces being connected by a through-going opening, wherein the button structure comprises a push-button, a switch according to the above, and a flex assembly, the switch being configured to extend at least partially through the opening between the push-button and the flex assembly. Thus tactility is increased and the risk of button jamming is reduced in comparison with prior art solutions wherein the sealing means is arranged between the push button and the switch. Further, the waterproofing surfaces in the housing may be machined at the same time as the through-going opening, which results in short tolerance stack up between the push-button and the switch. 
     In a first possible implementation form of the second aspect, the switch is electrically connected to the flex assembly. 
     In a second possible implementation form of the second aspect, the switch is connected to the flex assembly by means of soldering. 
     In a third possible implementation form of the second aspect, the sealing means is configured to seal the opening from ingress of fluid into the electronic device in a direction from the external surface to the internal surface. 
     In a fourth possible implementation form of the second aspect, the switch is configured to be inserted into the opening in a direction from the internal surface, and the flex assembly is configured to abut the internal surface. This solution keeps the switch in place within the through-going opening, hindering the switch from moving in a direction towards the external surface. 
     In a fifth possible implementation form of the second aspect, the button structure further comprises a support plate configured to lock the flex assembly to the housing. This solution hinders the switch from moving in a direction towards the internal surface. 
     According to a third aspect, there is provided an electronic device configured to receive a button structure according to the above, the electronic device comprising a housing having a first external surface, a second external surface, a third external surface, and an internal surface, the first external surface and the internal surface being connected by a through-going opening, the button structure being configured to extend at least partially through the opening. 
     Such an electronic device will not only be waterproof, but also maintain push-button tactility and hence user satisfaction. 
     In a first possible implementation form of the third aspect, the second external surface extends perpendicular to the first external surface and a first groove extends from the second external surface to the opening, the first groove being configured to receive a button lock plate adapted for interlocking a push-button of the button structure with the button lock plate such that the push-button cannot be removed from the opening without removing the button lock plate from the first groove. This solution keeps the push-button from moving in a direction towards the external surface of the housing. 
     In a second possible implementation form of the third aspect, the third external surface extends in parallel with the second external surface and a second groove extends from the third external surface to the opening, the second groove being configured to receive a support plate adapted for interlocking housing with the support plate such that the button structure cannot be removed from the opening without removing the support plate from the second groove. 
     According to a fourth aspect, there is provided a method of providing an electronic device with a button structure according to the above, the electronic device comprising a housing having a first external surface and an internal surface, the surfaces being connected by a through-going opening, the method comprising the steps of inserting the push-button partially into the opening, attaching the push-button to the housing, inserting the switch at least partially into the opening, in a direction from the internal surface towards the first external surface, such that the flex assembly, connected to the switch, abuts the internal surface, attaching the switch and the flex assembly to the housing. This method increases the tactility of the push-button and reduces the risk of button jamming in comparison with prior art solutions wherein the sealing means is arranged between the push button and the switch. Further, the waterproofing surfaces in the housing may be machined at the same time as the through-going opening, which results in short tolerance stack up between the push-button and the switch. 
     In a first possible implementation form of the fourth aspect, the method comprises inserting the push-button into the opening in a direction from the first external surface towards the internal surface. Such a solution allows for simple and quick mounting of the different components. 
     In a second possible implementation form of the fourth aspect, the housing further comprises a second external surface extending perpendicular to the first external surface, a first groove extending from the second external surface to the opening, and the method comprises inserting a button lock plate into the first groove, the push-button interlocking with the button lock plate such that the push-button cannot be removed from the opening without removing the button lock plate from the first groove. 
     In a third possible implementation form of the fourth aspect, the housing further comprises a third external surface extending in parallel with the second external surface, a second groove extending from the third external surface to the opening, and the method comprises inserting a support plate into the second groove, the support plate interlocking with the housing such that the button structure cannot be removed from the opening without removing the support plate from the second groove. 
     These and other aspects will be apparent from the embodiments described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the following detailed portion of the present disclosure, the aspects, embodiments and implementations will be explained in more detail with reference to the example embodiments shown in the drawings, in which: 
         FIG. 1  shows an elevated view of a switch and a flex assembly in accordance with one embodiment of the present invention; 
         FIG. 2  shows an exploded and elevated view of the switch in the embodiment shown in  FIG. 1 ; 
         FIG. 3 a    shows an elevated front view of a button structure and a partial housing in accordance with another embodiment of the present invention; 
         FIG. 3 b    shows an elevated rear view of the embodiment shown in  FIG. 3 a   , with switch and flex assembly separated from the housing; 
         FIG. 3 c    shows an elevated rear view of the embodiments shown in  FIGS. 3 a  and 3 b   , with switch and flex assembly removably inserted into an opening in the housing; 
         FIG. 3 d    shows an elevated rear view of the embodiments shown in  FIGS. 3 a  to 3 c   , with switch and flex assembly inserted and locked into an opening in the housing; 
         FIG. 4 a    shows a cross-sectional view of the button structure and housing shown in  FIG. 3   b;    
         FIG. 4 b    shows a cross-sectional view of the button structure and housing shown in  FIG. 3   d;    
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an embodiment comprising a switch  1  and a flex assembly  14 . The switch  1  is electrically connected to the flex assembly  14 , for example by means of reflow soldering. The flex assembly  14  comprises an L-shaped flex  14   a  and a flex stiffener  14   b  which not only stiffens the flex  14   a  but also guides a support plate  15  arranged behind the stiffener  14   b  when the switch  1  is mounted in an electronic device. The switch comprises a switch body  2 , a switch contact  3 , a switch contact cover  5 , and sealing means  6 . 
     The switch body  2  comprises plastic material and is preferably manufactured by means of insert molding. Further, the switch body  2  is provided with stamped metal inserts used together with signal lines which are soldered onto the flex  14   a . As shown in  FIG. 2 , the switch body comprises of two sections, a first switch body section  2   a  and a second switch body section  2   b , arranged along the center axis of the switch body  2 . The metal inserts are mainly located in the second switch body section  2   b.    
     In one embodiment, the first switch body section  2   a  has cross-section which is larger than that of the second switch body section  2   b . The area of both sections is rectelliptical when seen in the direction of the switch center axis. By rectelliptical is meant a rectangular shape having rounded corners. The cross-section could also have any other suitable shape such as an elliptical, oval, or rectangular area. I.e., a side cross-sectional view of the switch reveals an essentially T-shaped switch body, while a frontal or rear cross-sectional view reveals one or two rectellipses, depending on if the cut has been made through the first switch body section  2   a  or the second switch body section  2   b.    
     The switch contact  3 , in one embodiment comprising a dome, is configured to be arranged in a slot  4  arranged at the free end of the first switch body section  2   a . A switch contact cover  5  is provided to cover the switch contact/dome  3  and the slot  4 , e.g. by means of laser welding or adhering the switch contact cover  5  to the above mentioned free end. 
     A sealing means  6 , in one embodiment a gasket, covers the circumference of the second switch body section  2   b . The sealing means/gasket  6  comprises a circumferentially extending ridge  7 . The sealing means/gasket  6  can be a separate rubber component to be slid onto the switch body, or can be molded directly onto the switch body  2 , preferably the second switch body section  2   b , by means of liquid injection molding. 
       FIGS. 3 and 4  show embodiments of a button structure  8  arranged in an electronic device such as a mobile phone. The electronic device comprises a housing  9  which has a first external surface  10   a , facing the exterior, and an opposing internal surface  11 , facing the interior of the electronic device. The housing further comprises a second external surface  10   b  and a third external surface  10   c , extending in parallel with each other and perpendicular to the first external surface  10   a  and the internal surface  11 . The first external surface  10   a  and the internal surface  11  are connected by a through-going opening  12 , extending essentially perpendicular to both surfaces. The first external surface  10   a  may be a planar surface, but it may also be somewhat curved, i.e. at least partially convex, as seen in  FIGS. 4 a  and 4 b   . The internal surface  11  comprises at least one planar surface, i.e. it may comprise several parallel planar surfaces such that the internal surface  11  is a stepped surface. 
     The button structure  8  comprises the switch  1  and flex assembly  14  as described above, as well as a push-button  13  intended to protrude from the housing  9  of the electronic device. The switch  1  is configured to extend at least partially through the opening  12  between the push-button  13  and the flex assembly  14 . As previously mentioned, the switch  1  is electrically connected to the flex assembly  14 , e.g. by means of a soldering process such as reflow soldering. 
     The switch  1  comprises sealing means  6  configured to seal the opening  12  from ingress of fluid into the electronic device in a direction from the external surface  10   a  to the internal surface  11 . 
     When providing an electronic device with a button structure  8 , the push-button  13  is inserted into the opening  12  in a direction from the first external surface  10   a  towards the internal surface  11 . The push-button  13  is inserted only partially such that it protrudes somewhat from the opening  12  and housing  9 . The push-button  13  is thereafter attached to the housing  9  by means of a button lock plate  17 . 
     The button lock plate  17  is inserted into a first groove  16   a , which extends between the second external surface  10   b  and the opening  12 . This is shown schematically in  FIG. 4 a   . The second external surface  10   b  extends perpendicular to the first external surface  10   a . The push-button  13  is configured to interlock with the button lock plate  17  such that the push-button  13  cannot be removed from the opening  12  without first removing the button lock plate  17  from the first groove  16   a.    
     The switch  1  is inserted at least partially into the opening  12  in a direction from the internal surface  11  towards the first external surface  10   a , and the flex assembly  14  is configured to eventually abut the internal surface  11 , such that the flex assembly  14  stops the movement of the switch  1  through the opening  12 . See  FIGS. 3 b  and 3 c   . I.e., the switch  1  cannot extend past the external surface  10   a  due to the flex assembly  14  abutting the internal surface  11 . The flex assembly  14  further comprises a support plate  15  configured to lock the flex assembly  14 , and hence the switch  1 , to the housing  9 . 
     The support plate  15  is inserted into a second groove  16   b  which extends between the third external surface  10   c  and the opening  12 , as shown in  FIG. 3 d   . The third external surface  10   c  extends perpendicular to the first external surface  10   a  and parallel with the second external surface  10   b . The support plate  15  is configured to interlock with the housing  9  such that the button structure  8  cannot be removed from the opening  12  without first removing the support plate  15  from the second groove  16   b.    
     The various aspects and implementations has been described in conjunction with various embodiments herein. However, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed subject-matter, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. 
     The reference signs used in the claims shall not be construed as limiting the scope.