Patent Publication Number: US-2023152570-A1

Title: Switch button for an endoscope

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from and the benefit of European Patent Application No. EP21207467, filed Nov. 10, 2021, which is incorporated by reference herein in its entirety. 
     TECHNICAL FIELD 
     The invention relates to an endoscope with an electrical switch located on a handle of the endoscope and to a method of manufacturing the endoscope with the electrical switch. 
     BACKGROUND 
     Endoscopes, in particular insertion endoscopes, normally comprise a proximal handle from which an insertion cord extends towards the distal end of the endoscope. The insertion cord is adapted to be inserted into a body cavity. At the distal end the insertion cord comprises an articulated bending section the bending of which can be controlled by an operator using wheels and/or levers or the like at the handle. A tip part accommodates illumination and imaging electronics to generate images and video of a distal or lateral scene. An attached video processing apparatus, such as a monitor with a display screen, is used to present the images and video so that the operator of the endoscope is able to track movement during and after said insertion and possibly save the images and video. 
     Electrical switches may be needed to save such images and video and for other purposes involving electrical control or supply signals. For example, an electrical signal generated by an electrical switch may be used to engage a source of vacuum to suction fluids through a working channel or to engage a pump to irrigate a scene by pumping a liquid through a working channel of the endoscope. In this respect, it is well known to place such switches on the handle so that their operating members, i.e. switch buttons, are in positions that are easily accessible by the operator’s fingers during use of the endoscope. 
     It is known to provide endoscope handles, where the switches and switch buttons are attached to an exterior surface of the handle, e.g. as adhesive foil switches. This minimizes the risk of undesired fluids and other pollutants entering into the handle, because the handle integrity needs only be broken in one place for the passage of electrical wires, and this place may be covered by the foil of the foil switches themselves. 
     U.S. Publication No. 2021/0169307A1 discloses an endoscope with an operating switch located inside the handle and a switch button arranged in the handle housing wall. The switch button is adapted for a multiple use endoscope, thus requiring a series of elements to securely attach the operating switch to protect electronics and other delicate parts within the handle during cleaning procedures involving aggressive cleaning fluids and high temperature and pressure from autoclaving. To achieve this, the electronics, including a switch unit, are sealed and fixated by a series of assembling elements, namely an elastic portion, a pressing member and a switch member. This renders the switch assembly more complex than needed for single use, i.e. disposable endoscopes, and, in consequence, has the drawback of being time consuming and costly to assemble. 
     U.S. Pat. No. 5,618,212 discloses a foot-operated pedal with switches for a water vehicle. Similar to what is described for endoscopes above this pedal uses a switch foil on the exterior of a housing. The switch buttons are provided on one large cover with legs that snap into engagement with the interior wall of the housing. The cover seals the interior from wet or moist surroundings when used in a motorized water vehicle. 
     BRIEF DESCRIPTION OF THE DISCLOSURE 
     It is a first object of the disclosure to provide a switch button which is easily manufactured and facilitates the assembly of an endoscope, in particular so as to reduce assembly time of the endoscope and reduce manufacturing costs. Furthermore, the switch button should provide good sealing properties and attachment of relevant parts of the endoscope handle while being elastically deformable under the pressure from a finger. 
     According to a first aspect of the disclosure this object is achieved by a switch button for an endoscope handle with a housing wall defining an outer handle surface and an interior compartment and at least one electrical switch located on a carrier within said interior compartment, wherein said housing wall and said carrier comprises a number of through holes adapted for the switch button, the switch button comprising: an operating part elastically deformable under the pressure from a finger of an operator, a number of legs, each leg comprising a spacer section, a barb section and an auxiliary section. 
     In this way, a switch button is adapted to fully penetrate the housing wall and the electronic switch board, thereby providing a simpler and effective assembling solution. During assembly, the auxiliary section of the legs functions as an assembly aid to allow a secure grab of the legs of the switch button in order to easily pull the legs through the through holes of the housing wall and the switch board to complete the assembly. 
     According to a second aspect of the disclosure the object is achieved by a method for manufacturing a switch button according to the first aspect of the disclosure wherein the switch button is manufactured by injection moulding. 
     According to a third aspect of the disclosure the object is achieved by a method for mounting a switch button in an endoscope comprising: providing an endoscope having a handle with a housing wall having a number of through holes and defining an outer handle surface and an interior compartment, providing a switch button according to the first aspect of the disclosure, inserting the legs of the switch button through the through holes of the handle housing from the outer handle surface, inserting the legs of the switch button into the through holes of the carrier for the electrical switch button, and passing the barb section completely through the through holes of the carrier by pulling the auxiliary section. In this way a simple assembly method is provided in which the switch button functions as a sealing mechanism. The switch button further functions as an assembly element to fixate the switch button in the interior compartment of the endoscope handle. 
     According to a fourth aspect of the disclosure the object is achieved by an endoscope comprising a switch button manufactured according to the second aspect of the disclosure. 
     According to a fifth aspect of the disclosure, the object is achieved by a system comprising a video processing apparatus and an endoscope according to the fourth aspect of the disclosure connectable to the video processing apparatus. 
     In an embodiment of the first aspect of the disclosure the auxiliary section has a smaller diameter than the spacer section. This facilitates the insertion of the legs into the through holes of the handle housing and the carrier. 
     In an embodiment the barb section completely encircles the leg. This ensures the best possible retention of the carrier. 
     In an embodiment the switch button further comprises a plunger adapted to operate the electric switch. This facilities assured and consistent activation of the electrical switch. 
     In an embodiment the plunger comprises a contact. This allows the switch to be constituted directly by conductors on the carrier, thus saving a separate electrical switch unit. 
     In an embodiment, the switch button is adapted to seal the through holes of the endoscope handle housing wall when mounted on the endoscope handle. This further protects the endoscope handle from undesired ingress of fluids and pollutants. 
     In an embodiment, the switch button is of an elastomeric material with a shore A hardness in the range 40 to 70, preferably in the range of 50 to 60. This ensures good sealing and good activation of the electric switch. 
     In an embodiment, the auxiliary section comprises a break zone. This may avoid a separate step of cutting away any disturbing excess length of the auxiliary section after assembly of the switch. 
     In an embodiment, the break zone has a cross sectional area smaller than the auxiliary section. This will weaken the auxiliary section in a desired location and ensure that after assembly the remaining length of the auxiliary section, has a suitable length. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the following, the disclosure will be described in greater detail with reference to non-limiting exemplary embodiments and the enclosed schematic drawings, on which: 
         FIG.  1    shows a visualization system comprising an endoscope and a video processing apparatus according to one embodiment of the present disclosure; 
         FIG.  2    shows one part of a handle housing forming an interior compartment of the handle; 
         FIG.  3    shows a switch harness with three switch assemblies attached to a carrier circuit according to an embodiment of the present disclosure; 
         FIG.  4    shows a cross-section of an embodiment of an operating part according to the disclosure of the switch assemblies of  FIG.  3   ; 
         FIGS.  5  and  6    illustrate two states of the operating part of  FIG.  4   ; 
         FIG.  7    shows an enlarged view of the proximal end of the part of the handle housing of  FIG.  2   ; 
         FIGS.  8  to  11    show elevation, perspective and plan views of components of the switch assemblies of  FIG.  3   ; 
         FIG.  12    shows a variation of the operating member of  FIG.  4   ; 
         FIGS.  13  to  15    show elevation and cross-sectional views of components of switch assemblies according to another embodiment of the disclosure; and 
         FIG.  16    shows an elevation view of components of a switch assembly according to a further embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Turning first to  FIG.  1   , a visualization system 1 comprising an endoscope  2  and a video processing apparatus (VPA)  30  according to the present disclosure are shown. The endoscope  2  has a proximal end with a handle  4  from which an insertion cord  20  extends. The handle  4  may be ergonomically designed to be comfortably held and operated with a single hand during use by the operator and may comprise a housing  6  having two halves, or parts, designated as  6   a  and  6   b . The distal end of the insertion cord  20  may constitute an insertion tube  22 , a bending section  24 , and a tip part  26  at the distal end of the endoscope  2 . The bending section is articulated by a designated button  10  on the handle. The tip part  26  comprises a camera. One or more switch buttons  8  on the handle  4  may cooperate with the VPA  30  and the camera to save images and/or video. The switch buttons  8  and additional switch buttons may be used for other purposes, including actuation of irrigation and vacuum systems coupled with the endoscope  2 . A cable  12  having a connector  14  is provided to electrically connect the endoscope  2  with the VPA  30  to display content, e.g. images and video, obtained with the camera. 
     In the present embodiment, the VPA  30  comprises a housing  32  and a display screen  34 . In other embodiments the display screen  34  is omitted. In both embodiments the VPA  30  may communicatively connect with a remote display screen via wireless, HDMI, internet, or other known wired communication configurations, protocols, networks and systems. 
       FIG.  2    shows another embodiment of a housing part  6   b  of the handle  4  revealing an interior compartment  40  defined by a handle housing wall  42  of the handle  4  together with a complementary handle housing wall (not shown) of the housing part  6   a . The handle depicted in  FIG.  2    differs slightly in layout from that of  FIG.  1   , thus illustrating that the present disclosure relates to a multitude of different layouts of handles for endoscopes. The endoscope  2  comprises an inner handle surface  44  directed towards the interior compartment  40  and an outer handle surface  46  opposite the inner handle surface  44 . A dashed perimeter  50  encloses a proximal portion of the handle  4  which is enlarged and described in more detail with reference to  FIG.  7   . The proximal portion of the handle  4  includes a switch assembly  52 . In some embodiments, some components of the switch assembly  52  may, optionally, be provided in a switch harness  54 . For example, the switch harness may comprise a flexible circuit board connecting two electrical switches. 
       FIG.  3    shows an embodiment of the switch harness  54 . In the present embodiment the switch harness  54  comprises three switch assemblies  52 , a carrier circuit  56 , and an electrical connector  58 . The electrical connector  58  comprises connectors or pads electrically connected by the carrier circuit  56  to the three switch assemblies  52 . When a switch of a switch assembly  52  is actuated, a corresponding signal is communicated via the carrier circuit  56  to the electrical connector  58  and through the electrical connector  58  to a processor located in the handle  4  or in the VPA  30 . 
     The switch assembly  52  will now be described with reference to  FIGS.  3  to  6  and  8  to  11   . The switch assembly  52  includes an electrical switch  60  positioned in the interior compartment  40  and having a switch body  62  with an actuation surface  64  and a carrier board  66  opposite the actuation surface  64 , the carrier board  66  (best seen in  FIG.  11   ) has two or more apertures  68  corresponding to two or more apertures  48  (shown in  FIGS.  2  and  7   ) in the housing  6 . The actuation surface  64  is aligned with an actuator aperture  49  (shown in  FIGS.  2  and  7   ) in the housing. The switch body includes electrical components linked with the actuation surface  64 . The electrical switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of switch is an electromechanical device consisting of one or more sets of movable electrical contacts connected to external circuits. When a pair of contacts is touching current can pass between them, while when the contacts are separated no current can flow. Switches are made in many different configurations; they may have multiple sets of contacts controlled by the same knob or actuator, and the contacts may operate simultaneously, sequentially, or alternately. Other switches include integrated circuits in which a transistor or other electronic component can be operated to switch current flow. The transistor includes three contacts, two for passing current and one, referred to as the base contact, for allowing or ceasing current flow between the two contacts. A pair of contacts can be provided to allow a voltage to reach the base contact, as is known in the art. Electrical switches may retain a given state until actuated again or may only hold a state while being actuated. Any known or future developed switch actuated by pressing or releasing a contact surface may be used. 
     In some embodiments, a plunger of the operating part, e.g. the plunger  88  described below, includes an electrically conductive distal surface. The electrically conductive distal surface may be comprised by a metallic layer bonded to a distal surface of the plunger. The switch body may enclose two contacts on a printed circuit board, such as the carrier circuit  56  shown in  FIG.  3   . Thus, when the finger pad is pressed, the electrically conductive distal surface closes a gap between the two contacts, the electrically conductive distal surface and the two contacts forming the electrical switch. Alternatively, the two contacts overlap and a plunger without the electrically conductive distal surface presses one of the contacts into the other, the plunger and the two contacts forming the switch. A thin layer of material may separate the two contacts to ensure they do not connect inadvertently. Forming switches as described in this paragraph reduces manufacturing costs by forming the switch in the carrier circuit. The contacts may be formed in a copper layer of a flexible circuit board, for example. In one variation, a bridge of metallic material may be added instead overlapping contacts and/or an electrically conductive distal surface. The bridge of metallic material can be added via a thin adhesively bonded foam layer holding ends of the bridge, the middle of the bridge connecting two contacts of the carrier circuit. 
     The switch assembly  52  also comprises an operating part  70  comprising a finger pad  72  having a finger surface  74 , a ring  76  connected to and extending from the finger pad  72 , two or more legs  80  connected to and extending from the ring  76 , each of the legs comprising a peripheral surface  81  and an electrical switch retention protrusion  84  extending radially outwardly from the peripheral surface  80 . The ring has an optional actuator aperture  78  encircling a plunger  88  and an interior surface  79  opposite the finger pad  72 , the interior surface facing the exterior surface  42  of the housing. The actuator aperture  78  makes it easier to push the plunger  88  down when operating the finger pad and contributes to a more comfortable and less energy demanding operation. 
     The two or more legs  80  traverse the two or more apertures  48  of the housing and the two or more apertures  68  of the carrier board  66  to align the actuator aperture  49  of the housing with the actuation surface  64  of the electrical switch  60 . The electrical switch retention protrusions  84  extend through the two or more apertures  68  of the carrier board  66  and secure the electrical switch  60  to the housing  6  in a predetermined position defined by the apertures. The finger pad  72  comprises elastically deformable material configured to extend, from a rest position shown in  FIG.  5    to an engaged position shown in  FIG.  6    and exemplified by a depression distance D travelled by the finger surface  74  toward the electrical switch  60  when pressure is applied to the finger surface  74 . The finger pad  72  is biased by its composition to retract to the rest position when the pressure is released. The shape of the finger pad may aid to further bias it to the rest position (e.g. inverted cup shape). Extension and/or retraction of the finger pad  72  translates the plunger  88  to actuate the electrical switch  60 . The switch assembly  52 , and variations thereof, are further described below. 
     The handle  4  may, as indicated above, comprise two or more housing parts  6   a ,  6   b  fitted together during the assembly process to partly or fully enclose the interior compartment  40 . As can further be seen from  FIG.  2   , the at least one electrical switch  52  may be placed on the carrier circuit  56 . It should be noticed that the carrier circuit as shown in  FIG.  2    is not yet in its fully assembled state, as only one switch has been mounted. The carrier circuit  56  is in this embodiment a flexible sheet, in particular a flexible printed circuit board or a flat ribbon cable, that can adjust to curvatures of the inner handle surface  44 . An added advantage is that the switches do not have to be precisely mounted on the flexible carrier circuit since some slack in the carrier circuit is permissible between switches. In this respect it should be noticed that  FIGS.  2  and  7    show the carrier circuit  56  during assembly, i.e. with only one of three switches in place and securing the switch harness to the handle housing  6 . The carrier circuit  56  may, in another embodiment, be of a more rigid material such as an epoxy based printed circuit board. In either case the carrier circuit  56  may also incorporate the connector  58  for electrically connecting the switch harness to wires or cables of the endoscope  2 , e.g. leading to the VPA  30  via the cable  12 . The switches may also be directly connected to the wires or cables of the endoscope  2  without a switch harness. 
       FIG.  7    shows an enlarged version of the top part of the endoscope handle 6 from  FIG.  2    where the electrical switch  60  is embodied with the holes  68  configured to align with the holes  48  of the handle housing  6 .  FIG.  7    additionally shows that the electrical switch  60  is assembled with the handle housing  6  by using the legs  80  to secure the carrier board  66 . 
     Referring now to  FIGS.  8  to  11   , preferably the operating part  70  is made of an elastomeric material in a single-piece construction. The material can be a natural or synthetic rubber. In yet another embodiment it may be a silicone. The material from which the operating part  70  is made preferably has a shore A hardness in the range  40  to  70 , more preferred in the range of  50  to  60 . The legs  80  may be characterized as having sections  82 ,  84  and  86 . A material with such specifications results in an operating part  70  that conforms to the curvature of the outer handle surface  46  and thereby increases the sealing properties of the operating part  70 . 
     The section  82  is a spacer section, section  84  is the electrical switch retention protrusion, and section  86  is an auxiliary section. Section  82  extends from the interior surface  79  of the ring  76  to the section  84 . The length of the section  82  aids in setting a compression tension between the interior surface  79  and the section  84 . The compression tension can be sufficient to firmly secure the electrical switch  60  to the handle 6 and simultaneously seal the interior surface  79  with the exterior surface  46 . Thus, the composition and structure of the operating part  70  simultaneously secures the electrical switch  60  to the handle 6 and seals the holes  48 ,  49 . Other characteristics of the legs  80 , such as diameter, aid in setting the desired compression tension. 
     In a preferred embodiment the spacer section  82  has a length corresponding the combined thickness of the handle housing wall  42 , the switch body  62 , and the carrier board  66 . In another embodiment the length of the spacer section  82  may be shorter than the combined thickness of the handle housing wall  42 , the switch body  62 , and the carrier board  66 . Consequently, the operating part  70  will exert a larger pressure on the outer handle surface  46  and provide better sealing properties. To further enhance sealing the operating part  70  will, in its mounted position, completely cover the holes  48  intended for the legs  80 . The spacer section  82  may have a crosswise dimension, or in some embodiments diameter, preferably adapted to fit in a sealing manner in the holes  48  in the handle housing wall  42 . The crosswise dimension may be slightly larger than the crosswise dimension of the holes  48 , e.g. 1, 2, 3, 5, or up to 10% larger. 
     As shown in  FIG.  9   , the section  84  may comprise a conical shape with a longitudinal cut-out  85  provided to facilitate radial compression and thus insertion of the section  84  through the holes  86 . The shape of the section  84  may comprise a plurality of longitudinal protrusions instead of a single conically shaped protrusion. The section  84  presents a surface larger, closer to the ring, than the holes  68  such that the section  84  can only reasonably pass through the holes  68  in one direction. In some variations, the section  84  completely encircles the periphery of the leg. In a preferred variation the section  84  partly encircles the leg  82  to an extent in the range of 180°-360°. This encircling may be continuous or in a number of discrete barbs e.g. as circular sectors. The barbs are preferably conical to easily guide them through the apertures of the handle housing and the carrier circuit during assembly. Consequently, the sections  84  will not move reversely through the apertures once mounted and the switch assembly will be securely attached to the handle housing. 
     The section  86  facilitates insertion of the section  84 . A user can insert the section  86  through the hole  68  and then pull the section  86  to stretch the leg  80  while simultaneously pushing the electrical switch  60  toward the handle housing  6  until the section  84  passed through the hole  68 . After mounting of the electrical switch  60  the section  86  may be cut and removed. The auxiliary section  86  may have a crosswise dimension smaller than the crosswise dimension of the spacer section  82 . This will facilitate the insertion through the through holes  48  in the handle housing wall  42  and the corresponding holes  68  arranged in the carrier board  66 . The holes  48  and  68  correspond in the sense that their spacing and pattern are the same, so that the holes  68  in the carrier board  66  are arranged around the switch base  62  and the plunger hole  49 . Furthermore, the auxiliary section  86  may, in some embodiments, have a taper in the direction away from the switch base  62 . The endoscope of claim 10, wherein each of the legs includes a break section having a cross-section smaller than the auxiliary section, the break section being positioned between the electrical switch retention protrusion and the auxiliary section. In one embodiment the break zone may be a structural weakening in the form of a slit. 
     The finger pad, the ring, and the two or more legs in any of the disclosed embodiments may be comprised of the same elastically deformable material. Alternatively, the hardness or tackiness of the ring, the finger pad, and the legs may be varied to enhance the functionality of each part. The composition of elastic material can be varied in a multi-port injection molding process, for example, each port adding a different material. Alternatively, the finger pad, the ring, and the two or more legs may be bonded to form a single-piece part and not formed integrally as a single-piece part. 
     Referring to  FIG.  12   , the legs may comprise a break section  87  having a cross-section smaller than the auxiliary section, the break section being positioned between the electrical switch retention protrusion and the auxiliary section. The break section is configured to facilitate removal of the auxiliary sections after assembly. 
     In the embodiment shown in  FIGS.  4 ,  8  to  10 , and  12   , the operating part  70  includes the plunger  88 . The plunger  88  may extend in a direction that is parallel with the legs  80 . In this embodiment the finger pad  72  has a dome shape. In other embodiments, the finger pad  72  may have square, oval or other shapes. 
     In the embodiment shown in  FIGS.  4 ,  8  to  10 , and  12   , the operating part  70  includes legs with circular cross-sections. All sections of the leg may have circular cross-sectionals. In other embodiments the cross-section of the legs may be square or have more complex shapes. Round holes and legs may be easier to manufacture than holes with corners, such as square or rectangular shapes. 
       FIGS.  13  to  15    show another embodiment of a switch assembly, denoted by numeral  90 , having an operating member  92  with legs  100  having sections  102  and  104 , which are analogous to operating member  70  with legs  80  having sections  82  and  84 . The operating members differ in that only two legs are present in the operating member  92 , and these legs have rectangular cross-sections instead of round cross-sections. The legs may include auxiliary sections, and potentially break sections as well. 
     Either the operating part, the electrical switch, or both may comprise a plunger. An operating part plunger  88  is shown in  FIGS.  8  to  10   . In  FIG.  16    a switch assembly  102  is shown having an operating member  110  and an electrical switch  106 . The operating member  110  has a shorter plunger  104  than the plunger  88  and the electrical switch  106  has a switch plunger  108 . The plungers cooperate to activate the switch. 
     A layer of material may be interposed between the ring and the handle housing to increase sealing. The material may be sprayed, spread or added as a thin self-adhesive to the ring, for example. 
     During assembly, an assembler will take the operating part  70  and easily guide the auxiliary section  86  through the holes  48  of the handle housing wall  42 , due to the narrower and preferably tapered design of the auxiliary sections  86 . This will save time during the assembling process as the assembler will easily insert and continue to guide the auxiliary section  86  through the holes  68  of the carrier board  66 . Once the auxiliary section  86  has been successfully and effortlessly guided all the way through both sets of holes, the assembler will grab the auxiliary sections  68  now located in the interior compartment  40 . At this point the assembler will pull each auxiliary section  86 , thereby forcing the section  84  through both sets of holes. The spacer section  82  is now located in the holes  48  and  68  to ensure that the switch assembly  52  and the handle housing wall  42  are held tightly against each other with a suitable tension to allow the electrical switch  60  to be operated only when the operating part  70  is depressed. However, for the given ranges of hardness mentioned above the spacers will still ensure that the force is still sufficient to activate the electrical switch  60  rather than pushing the carrier board  66  with the switch body  62  away from the handle housing wall  42  without activation the electrical switch  60 . 
     After assembly the auxiliary sections  86  are no longer needed and may be removed e.g. by cutting away or otherwise removing any excess length thereof that could conflict with other internal parts of the endoscope  2 , e.g. pull wires and operating members thereof within the handle  4 . 
     The operating part may be integrally moulded as one unitary item and is preferably manufactured with injection moulding. This requires a moulding chamber that captures all the details of the operating part with as few moulding parts as possible. The operating part is preferably moulded with two moulding parts, a concave and a convex part. Due to the elasticity of the material with a Shore A hardness in the range of 40 to 70, it will be possible to retract the convex mould part from the concave mould part, even if the sections  84  are undercut. However, in order for the convex part to reach and form the plunger  88  and the plunger aperture  78 , it is preferred to form the section  84  with the cut-out  85  to allow room for the moulding part. 
     The embodiments shown in the figures and described herein are not to limit the scope of the invention, which is defined by the claims appended hereto. 
     Furthermore, the skilled person will appreciate that although described in the context of an endoscope the disclosed switch assembly may be used in a multitude of other devices where a simple way of securing a switch assembly inside a cavity is desired. Example other devices include laryngoscopes, endotracheal tubes, and other medical insertion devices. 
     The following items are examples of various embodiments and variations thereof disclosed above, and others: 
     1. A switch button for an endoscope handle with a housing wall defining an outer handle surface and an interior compartment and at least one electrical switch located on a carrier within said interior compartment, wherein said housing wall and said carrier comprises a number of through holes adapted for the switch button, the switch button comprising: an operating part elastically deformable under the pressure from a finger of an operator, a number of legs, each leg comprising a spacer section, a barb section and an auxiliary section. 
     2. A switch button according to item 1, wherein the auxiliary section has a smaller diameter than the spacer section. 
     3. A switch button according to any one of the preceding items, wherein the barb section completely encircles the leg. 
     4. A switch button according to any one of the preceding items, wherein the switch button further comprises a plunger adapted to operate the electric switch. 
     5. A switch button according to item 4, wherein the plunger comprises a contact. 
     6. A switch button according to any one of the preceding items, wherein the switch button is adapted to seal the through holes of the endoscope handle housing wall when mounted on the endoscope handle. 
     7. A switch button according to any one of the preceding items, wherein the switch button is of an elastomeric material with a shore A hardness in the range 40 to 70, preferably in the range of 50 to 60. 
     8. A switch button according to any of one of the preceding items, wherein the auxiliary section comprises a break zone. 
     9. A switch button according to item 8, wherein the break zone has a cross sectional area smaller than the auxiliary section. 
     10. A method for manufacturing a switch button according to any one of the preceding items, wherein the switch button is manufactured by injection moulding. 
     11. A switch button according to item 10, wherein the switch button is integrally moulded as one unitary item. 
     12. A method for mounting a switch button according to any of the preceding items comprising: providing an endoscope having a handle with a housing wall having a number of through holes and defining an outer handle surface and an interior compartment, providing a switch button according to any one of items 1 to 9, inserting the legs of the switch button through the through holes of the handle housing from the outer handle surface, inserting the legs of the switch button into the through holes of the carrier for the electrical switch button, and passing the barb section completely through the through holes of the carrier by pulling the auxiliary section. 
     13. An endoscope comprising a switch button manufactured according to the method of item 10. 
     14. A system comprising a monitoring device and an endoscope according to item 13 connectable to said monitoring device.