Abstract: A watertight switch comprises a cover and a base assembled together to form an accommodating space for mounting a switching module therein. The cover and the base, at the combination interface therebetween, respectively have a first junction interface and a second junction interface, which are inwardly shrunk to form a binding gap, the binding gap is gummed by an adhesive for fixedly combining and positioning the first and the second junction interfaces, and the adhesive will fill the binding gap without flowing over the first and the second junction interfaces.

Abstract: According to one embodiment, a keyboard unit that includes a keyboard body having a key top and a detecting unit detecting water. The detecting unit is positioned on the keyboard body so as to facing to an under side of the key top.

Abstract: A waterproof rotary switch includes a holder base that has hooks extending from the periphery, a switching component set that is mounted on the holder base and has a fixed metal terminal with a fixed contact, a movable metal terminal with a movable contact, and two conductors respectively connected to the fixed metal terminal and the movable metal terminal, an actuator that is mounted in the holder base and has an actuating portion rotatable with the actuator to move the movable contact of the movable metal terminal into contact the fixed contact of the fixed metal terminal to close the circuit or away from the fixed contact of the fixed metal terminal to open the circuit, and a top cover that covers the holder base to hold the switching component set and the actuator on the holder base and has a plurality of hook holes that receive the hooks of the holder base respectively and a plurality of wire slots for the passing of the conductors and a top wall sloping downwardly outwards to the periphery of the top co

Abstract: An electrical appliance housing including a hard plastic housing body defining a switch-actuating aperture. The aperture is sealed with a soft plastic membrane. An actuating button is fastened to a hard plastic base that is bonded to the membrane.

Abstract: A technique of preventing permeation of liquid and dust to electronic parts within a housing of an input device for an in-vehicle device. An input device of an in-vehicle device comprises a housing and a substrate stored in the housing. The housing comprises a button, a rod hole for guiding vertically a rod positioned under the button, taking the top of the button as an upper side, and the rod inserted in the rod hole. The substrate comprises an input element positioned under the rod. The rod is fitted with a covering member that covers the rod hole from above.

Abstract: Disclosed is a switch unit for use with a face plate. The switch unit has a seal connected thereto to facilitate the installation of the switch unit, as well as subsequent reorientation of the switch unit with respect to the face plate. In one form, the seal is connected to a top surface of a dolly housing of the switch unit. Also disclosed is a frame for removably retaining the switch unit to the face plate.

Abstract: According to one embodiment, an electronic apparatus has a housing. The housing has a first chamber to house circuit components, a second chamber parted from the first chamber, and a keyboard mounting portion to mount a keyboard. The keyboard mounting portion and second chamber are communicatively connected through a liquid inlet. A liquid outlet opening from the second chamber to the housing is formed below the liquid inlet. The liquid outlet has an opening area larger than the liquid inlet.

Abstract: A modular keyboard includes an upper casing, a lower casing corresponding to the upper casing, an electric conduction element and a circuit board. The upper casing includes a first side and a second side opposite to each other, and a plurality of press keys disposed on the first side. The lower casing is set for sealing the second side, and an enclosure space is formed between the upper casing and the lower casing. The electric conduction element is installed on the second side in the enclosure space, and the circuit board is installed between the electric conduction element and the lower casing. With a supersonic welding technique, the upper casing and the lower casing are engaged with each other to seal the enclosure space and isolate the electric conduction element in the enclosure space and the circuit board from the exterior.

Abstract: According to one embodiment, an information processing apparatus includes a key matrix unit having a plurality of switches, a plurality of operation keys which are provided in association with a part of the plurality of switches, and a first detection unit which executes a scan process for the key matrix unit, thereby detecting on/off states of the plurality of switches, the first detection unit executes a predetermined process in a case where the first detection unit detects that the switches, which are not associated with the operation keys, are in an ON state.

Abstract: The invention relates to an actuating device for closing and/or opening a movable part (2) of a motor vehicle, in particular a door, a rear flap or the like, with a housing (3), and a rotatably mounted touch element (4) which, upon actuation, acts on a switch (6) arranged behind the touch element (4) in a shielded interior space (5). According to the invention, it is provided that the touch element (4) is mounted pivotably in such a manner that the volume of the interior space (5) is essentially the same in every position of the touch element (4).

Abstract: Methods and apparatus are provided for an electrical assembly. The apparatus comprises a base member comprising a recessed portion and a circumferential flange, the recessed portion adapted to receive an electrical device and the flange having a channel on a first side and a sealing member comprising a retention portion and a protruding portion disposed on the retention portion, the retention portion adapted to at least partially enclose the circumferential flange with at least part of the sealing member disposed at least partially across the channel, and the protruding portion extending away from the channel.

Abstract: A connector structure of waterproof and explosion-proof button is provided. A waterproof element completely covers the connecting part of the connecting element. By pressing a first button bar of the waterproof element, a second button bar is driven to depress the button therein. A companion part inside the connecting element is connected and fixed with an explosion-proof element. The connector structure thus achieves the waterproof and explosion-proof effects and has the button function at the same time. The structure solves the problem of having too many elements and too complicated assembly process for achieving the waterproof effect in the prior art. According to the structure, the assembly of the connector structure is simple and both waterproof and explosion-proof effects are simultaneously achieved.

Abstract: A moisture-proof push-type switch module includes a first casing unit, a second casing unit, a first movable structure, and a push structure. The first casing unit has a first outer moisture-proof structure disposed around its outer side. The first casing unit has a first receiving room, a second receiving room, and an opening communicating between the second receiving room and the external environment. The second casing unit is mated with the first casing unit. The second casing unit has a second outer moisture-proof structure and a first movable element moisture-proof structure, and the first outer moisture-proof structure and the second outer moisture-proof structure are mated with each other. The first movable structure has a first movable element mated with the first movable element moisture-proof structure. The push structure passes through the opening in order to selectably push the first movable element.

Abstract: According to one embodiment, an electronic apparatus comprises: a casing comprising a circuit module; a keyboard mounting portion on which a keyboard is detachably mounted, and a cover detachably covering the opening. The key board mounting portion comprises an opening which allows a wiring electrically connecting the keyboard and the circuit module to be passed therethrough. An area of the opening is equal to or less than half of an area of the keyboard mounting portion.

Abstract: An electronic apparatus is provided with a housing including a top wall and a side portion extending from an edge of the top wall, a keyboard, and a keyboard placing portion on which the keyboard is placed, the keyboard placing portion including a bottom surface provided in the top wall. At least part of the bottom surface extends to the side portion of the housing.

Abstract: A switch assembly may include a housing having a body and an over-molded feature. The over-molded feature may include a flexible membrane sealingly engaged with the body and defining an actuation portion. The housing may be configured to sealingly engage a finish panel. A back cover may sealingly engage the housing, and a rocker may be included between the actuation portion and the back cover to transmit a force applied to the actuation portion to actuate a switch.

Abstract: A housing for a scale or load cell controller suitable for use in harsh environments. The housing includes a moisture-resistant front display unit coupled to a rear interface and mounting unit. The front display unit includes a front housing, a back housing, and a frame overlying a boundary or seal region between the front and back housings to provide a double moisture-resistant seal between the front and back housings. The front display unit defines an interior region including a display and a plurality of user input keys and controller circuitry. The front display unit is removably attachable to the rear interface unit. A moisture-resistant seal is also provided between the front display unit and the rear interface and mounting unit. The rear interface and mounting unit defines a recessed area supporting a battery pack, a power supply and an interface circuit board.

Abstract: The aim of the invention is to provide a simple and economical embodiment of an electronic key comprising dimensionally stable push buttons (31). To this end, a membrane (21) and a frame (22) are used is a 2K element (20) of a dual-component technology. The soft component of the 2K element (20) consists of a membrane (21), while the hard component is a frame (22) containing a free membrane field between the frame sections thereof. The housing (11) of the key has an opening (13) which is large enough to fit the entire push button actuation surface (34). The push buttons (31) are freely inserted from the inner side (16) of the housing (11) into the housing opening (13). The 2K element (20) thus secures the push button position in the housing (11). The push buttons (31) are limited at the top and at the bottom. The frame of the 2K element (20) provides the inner abutment (28) for the push buttons (31).

Abstract: An electrical device includes a housing, a circuit unit disposed in the housing, a waterproof keypad disposed in the housing at a position above the circuit unit, and a press member. The waterproof keypad includes a rigid layer, a resilient pad body, a waterproofing ring, and a plurality of keys. The press member is connected to the housing and presses against the rigid layer. The waterproofing ring is connected to a bottom face of the resilient pad body, abuts against the housing, and surrounds the circuit unit. A portion of a top face of the resilient pad body is connected immovably to a bottom face of the rigid layer. Another portion of the top face of the resilient pad body is exposed from the rigid layer. The keys are connected to the exposed portion of the top face of the resilient pad body and are exposed from the rigid layer.

Abstract: An electronic switch includes a housing having a base with opposite inner and outer sides, and a cover body having a main portion that cooperates with the inner side of the base to define a chamber, and an end portion cooperating with the outer side of the base to define a sealing space. A terminal has a connecting part extending through the base and the sealing space and adapted to be connected to the circuit board. A hollow portion projects outwardly from the outer side of the base into the sealing space, and confines an air-discharge hole communicating fluidly with the chamber. A first adhesive layer is disposed in the sealing space without covering the air-discharge hole. A sealing unit is attached to the base, and seals the air-discharge hole.

Abstract: A sealed electrical enclosure used in hazardous locations for enclosing circuit breakers having a bottom housing and a top housing with a labyrinth seal or joint formed therebetween, the bottom housing adapted to receive one or more circuit breakers, a first metal bus extending from a point internal to the bottom housing through a first end wall to a point external thereto, and a second metal bus extending from a point internal to the bottom housing through a second end wall to a point external to thereto, where the first and second metal buses are adapted to contact first and second electrical terminals of a circuit breaker when placed within the bottom housing, and a first vent positioned on the top housing for dissipating pressure buildup, wherein the top housing is removably secured to the bottom housing to allow for removal and replacement of a circuit breakers within the housing.

Abstract: A waterproof electronic device includes an upper shell and a lower shell configured for detachably and hermetically assembling with the upper shell. At least one of the upper shell and lower shell comprising a rubber layer disposed thereon to hermetically assemble with each other. The invention further provides a method for making the waterproof electronic device.

Abstract: A push-button arrangement and a push-button. The push-button comprises a fastening sleeve portion having a press portion at a first end thereof and a fastening member at a second end thereof for connecting the push-button to a fastening hole in a fastening plate. The outer surface of the fastening sleeve portion is provided with at least one conical sealing surface and the fastening hole, correspondingly, with a conical counter surface.

Abstract: A switch mechanism usable underwater including a cover serving as an exterior member, a shaft member displaceable in a longitudinal direction and fitted into a shaft hole having substantially the same cross-sectional area provided in the cover, an O-ring maintaining a water-tight sliding seal between the shaft member and the shaft hole, and a lever member movable about an axis for moving the shaft member by application of a pressing force applied to the lever member in a first direction against a force of a bias member, the pressing force being applied at a first point which is a first distance from said axis, the lever member engaging the shaft at a second point a second distance from said axis which is less than said first distance to move the lever member in a second direction opposite said first direction when the pressing force is removed.

Abstract: The present invention provides a switch mechanism usable underwater including a rear cover serving as an exterior member, two shaft members being displaceable in a shaft direction and fitting into two shaft holes having the same cross-sectional area provided in the rear cover, an O-ring watertightly maintaining the shaft member and the shaft hole, and a lever member being engaged with the two shaft members in a manner to be capable of pressing-down or pulling-up the shaft member, and being configured to balance water pressure applied to one shaft member with that applied to the other shaft member.

Abstract: An enclosure has an edge for defining a window opening. A keyboard is set in the window opening. A support member attached to the enclosure from the inside of the enclosure to receive the edge of the enclosure and the keyboard. A wall stands upright from the surface of the support member at a position outside the window opening. When coffee is spilled on the keyboard, the liquid flows into a space between the keyboard and the window opening. The surface tension of the liquid serves to prevent the liquid from immediately leaking outside the window opening through the gap between the edge and the support member. The liquid then starts leaking outside the window opening through the gap. The wall of the support member blocks the liquid. It thus takes a while before the liquid flows over the wall.

Abstract: A faceplate structure for a load control device comprises a bezel, an operating knob extending through an elongated rectangular opening of the bezel, and a sliding cover plate disposed behind the bezel. The bezel defines side walls and is adapted to be fixed to the load control device. The elongated rectangular opening extends along a vertical axis of the bezel. The operating knob is operable to vertically move along the length of the elongated opening. The cover plate is slidably coupled to the side walls of the bezel. The shaft of the operating knob is coupled to the cover plate, such that the cover plate is vertically movable with respect to the bezel. The cover plate covers the rear of the opening in all positions to which the cover plate can be moved by the operating knob.

Abstract: A dustproof cover is used in conjunction with a casing, which at least has a first opening, a second opening, a first engaging part and a first connecting part. The dustproof cover includes a first dustproof part, a second dustproof part, a second engaging part and a second connecting part. The first dustproof part corresponds to the first opening of the casing. The second dustproof part corresponds to the second opening of the casing. The second engaging part corresponds to the first engaging part of the casing. The second engaging part is located between the first dustproof part and the second dustproof part. The second connecting part is connected with the first connecting part of the casing. The first dustproof part is located between the second engaging part and the second connecting part. In addition, an electronic apparatus including the dustproof cover is also provided.

Abstract: In an improved pressure switch structure, a metal casing is provided for sealing and covering the exterior of the pressure switch, such that a wire contact point at an end of the pressure switch is sealed and protected from moisture, and a plug cap in a wire through hole of the metal casing is provided for wrapping and binding a power supply wire to achieve a fixed positioning effect, so that the power supply wire will not be pulled or loosened easily and is sealed and protected from moisture and dust.

Abstract: An improved electrical switch nut and boot seal assembly is provided having a stainless steel or aluminum nut and flexible boot to provide an exemplary fluid seal between an electrical switch and the electrical switch nut and boot seal device. The electrical switch may be a toggle switch or push button type circuit breaker or any other type electrical switch device where the advantages of the present invention make themselves useful such as may exist on any control panel of a recreational vehicle (i.e., boat, snowmobile, or other type land or water craft). A key feature of the invention is that the nut and flexible boot are separate pieces that can be mixed and matched to change the outer shape and/or colors of the various nuts and/or flexible boots. The fluid and moisture seal is provided by capturing a flange of the flexible boot between various inner surfaces of the nut and electrical switch.

Abstract: A metallic panel assembly having multilayer arrays of micropores includes a backlight module and a panel body. The backlight module is constituted of a first and a second light-guiding plate. First and second light-guiding microstructures are provided on the first and second light-guiding plates. A first and a second set of light-emitting units are disposed on one end of the first and second light-guiding plates, respectively. A first and a second shielding unit are disposed on the first and second light-guiding plates and the first and second sets of light-emitting units respectively. The panel body is disposed on one side surface of the first light-guiding plate. The panel body has thereon a plurality of hollowed portions with the hollowed portions encircling a key body. The key body has thereon a plurality of micropores. The plurality of micropores is arranged to form a pattern of each key body.

Abstract: According to one embodiment, an electronic apparatus with a keyboard coupled to a cable, comprises a housing including a wall on which the keyboard is mounted, the wall including an opening, a circuit board which is accommodated inside the housing, and to which the cable is coupled through the opening, a sheet which is arranged between the wall and the keyboard, and which covers the opening, the sheet including a cable insertion portion through which the cable is inserted.

Abstract: According to one embodiment, an electronic apparatus includes a housing, a unit supported on the housing, and a mounting section which is provided on the housing and on which the unit is placed. The mounting section includes an opening, a support wall which surrounds the opening and supports the unit, a cut portion which is provided in the support wall, and a lid which is fitted in the cut portion and is a part of the support wall.

Abstract: A washable switch that may be used in a keyboard is disclosed. In an embodiment, a housing of the keyboard may include a key opening and a support layer may be mounted in the housing. Key silos may be mounted on the support layer and input keys with support legs may be mounted in the key silos. In an embodiment the key silos may comprise an internally lubricated resin. An actuation unit and a keyboard circuitry may be in communication and encapsulated in a first and second barrier layer so as to provide a keyboard that may be safely placed in a dishwasher. If the keyboard is configured for wireless use, a sealable power source compartment sealably coupled to the keyboard circuitry may be provided with a removable door so as to allow the user, in operation, to access and replace a power source. The keyboard may include an externally exposed connector that may be sealed with a plug that may be attached to the housing by a tether.

Abstract: A waterproof keyboard comprises: keys, an elastic rubber layer, a circuit board layer, a bottom board, and a sealing layer. The keys are mounted on the bottom board on which a plurality of apertures are disposed, and the sealing layer is disposed under the bottom surface of the bottom board. Corresponding to the apertures on the bottom board, respective adhesives are formed on the sealing layer so as to firmly adhere the sealing layer to the bottom surface of the bottom board.

Abstract: A safety switch apparatus includes one or more switching elements in association with an operating head. A housing and a cover are provided for maintaining the switching element(s) therein. A switch cavity is formed between the housing and the cover to maintain the switching element(s) in the switch cavity between the housing and the cover. A plurality of cover-housing threads are provided by the housing and the cover in association with a plunger extending between the switch cavity and the operating head, thereby providing a weather-sealed and explosion-proof barrier for protecting the switching element(s).

Abstract: A device includes a printed circuit board having a first surface and a second surface. The printed circuit board defines an opening therethrough from the first surface to the second surface and a circuit formed on the first surface of the printed circuit board with no portion of the circuit intersecting the opening. The second surface of the printed circuit board at least partially bounds a first channel in fluid communication with the opening. A method of venting includes displacing air within a cavity of a switch by moving the air through one or more channels formed in a layer defining cut-outs in fluid communication with the cavity. The air is moved through an opening formed in a printed circuit board. The layer is positioned at a first side of the printed circuit board. In addition, the method includes moving the air through a venting channel positioned at a second, opposite side of the printed circuit board and into the surrounding environment.

Abstract: An enclosure has an edge for defining a window opening. A keyboard is set in the window opening. A support member attached to the enclosure from the inside of the enclosure to receive the edge of the enclosure and the keyboard. A wall stands upright from the surface of the support member at a position outside the window opening. When coffee is spilled on the keyboard, the liquid flows into a space between the keyboard and the window opening. The surface tension of the liquid serves to prevent the liquid from immediately leaking outside the window opening through the gap between the edge and the support member. The liquid then starts leaking outside the window opening through the gap. The wall of the support member blocks the liquid. It thus takes a while before the liquid flows over the wall.

Abstract: Enhancing efficiency in assembling a waterproof switch, and enhance flexibility of seal design. The waterproof switch 7 includes a plunger 11 accommodated in a cylindrical case 10 capable of moving in the longitudinal direction, and to which a spring 17 applies a force in a direction. One end of the plunger 11 is provided with a common contact point 16 which contacts with contact point terminals 18 and 19 when predetermined amount of displacement to the spring 17 which applies the force to the plunder 11 is provided. A concave portion 10a is that to which a seal 13 for a sliding part of the plunger 11 is attached, and this concave portion 10a is provided to an end portion of the case 10. Assembling is proceeded while recognizing how the seal 13 is attached thereto from the appearance in the assembling process.

Abstract: A switch assembly includes a circuit board having at least one circuit and a switch mechanism supported by the circuit board. The switch mechanism is operated to close the circuit. A housing sealingly surrounds the circuit board and the switch mechanism. Optionally, the housing may be overmolded around the circuit board and the switch mechanism. The housing may be configured to be mounted to an exterior portion of a vehicle such that the switch mechanism may be operated by an operated from the exterior of the vehicle.

Abstract: A dust-proof switch includes a housing inlayed with a plurality of terminals, an inner lid, an outer lid, a dust-proof cover and a shielding. The housing has a body; an accommodating recess is defined in the body. The accommodating recess includes a first cavity and a second cavity. The inner lid and the outer lid are respectively disposed in the first cavity and the second cavity. The inner lid has a dome and two U shaped ears defined at two symmetrical ends of the dome. The dust-proof cover is disposed on the housing and wedged in the U shaped ears of the inner lid to fix the domes.

Abstract: The present invention relates to an improved thin touch switch that includes a penetrating hole disposed on a plastic body and proximate to an exposed end of a metal component of a terminal and a high heat resisting and waterproof plastic material filled and sealed at the penetrating hole, such that when pins of the metal components of the touch switch are soldered to a printed circuit board, the plastic material used for sealing and combining the metal components and the plastic body can totally block the cleaning solution from entering from the joint that connects the metal components and the plastic body during the soldering process and can prevent possible short circuits to the metal components of the terminal, so as to effectively improve the life expectancy and safety of the touch switch.

Abstract: A bendable, washable, watertight key switch assembly is disclosed to include a polymeric flexible top layer made, which has key caps and a conducting member respectively bonded to the inside wall of each key cap, a polymeric flexible bottom layer defining with the flexible top layer an accommodation space, and a thin film circuit board set in the accommodation space and sealed to the flexible top layer and the flexible bottom layer with an adhesive, the thin film circuit board having printed switch contacts corresponding to the conducting members in the key caps for the contact of the associating conducting members to output a corresponding electric signal and a cable electrically connected to the printed switch contacts and extended out of the flexible top layer and the flexible bottom layer at one side for connection to an external electronic device.

Abstract: Provided is a waterproof/drainage structure for a lower casing (11) having a plurality of pushbuttons (16) on a surface thereof. The waterproof/drainage structure has a cover member (14) forming the surface and provided with a plurality of button holes (14a) the plurality of pushbuttons (16), and a sheet portion (17) retaining the plurality of pushbuttons (16) at predetermined positions. The waterproof/drainage structure includes a button unit (15), in which the sheet portion (17) is arranged along a back surface (14b) of the cover member (14) and in which an outer peripheral portion of the sheet portion (17) is held in close contact with the cover member (14), with the pushbuttons (16) being inserted in button holes (14c) of the cover member (14). The sheet portion (17) is provided with a groove-like drainage channel (22) having a channel portion that is opposed to each of the pushbuttons (16) and is larger than a surface area within a maximum outer periphery of the pushbuttons (16).

Abstract: On a switch cover attached to a switch body incorporating a switching mechanism and a regulating mechanism from above, an opening is provided to expose a part of an operation knob and to allow the operation knob to be swung. A through hole is provided on the switch body so as to vertically penetrate through the same in a position of the switch body in communication with the opening. Thus, fine sand that has entered through the opening can be discharged to the outside.

Abstract: A waterproof structure with a simple structure and a good assemble workability is provided. A recess portion is formed on a side of an inner casing, and a through hole is formed at the bottom of the recess portion. The through hole runs to a housing recess portion, and a dome switch opposes to the through hole in the inner casing. A protrusion of a cup member is inserted into the through hole from the outside of the inner casing. A protrusive portion protruding from the bottom surface of a push button is inserted into the opening of the cup member. A rubber sheet which couples the push button is sandwiched between the inner casing and a top cover and a back cover.

Abstract: A key input device includes a key input unit and an illuminating unit. The key input unit has a key cap, movable mechanism, pressure sensing part, and a frame housing these components. The illuminating unit illuminates the key cap from the bottom of this key input unit through the movable mechanism and the pressure sensing part. The key input unit and the illuminating unit are configured in such a way that they are independently waterproofed.

Abstract: A tactile feedback switching mechanism having a plurality of switching states. The tactile feedback switching mechanism includes a plunger switch having a plunger. When the plunger is displaced a given distance the switch changes state. A covering lies at least over the plunger switch and includes a border section and a deformation section. The covering may be formed from an elastic material such as an elastomer. When a user depresses the plunger, confirmation of a change in the state of the switch can be tacitly sensed by a change in resistance provided by the covering. The resistance of the covering changes by deformation of the deformation portion of the covering while the plunger is depressed.

Abstract: A simple, inexpensive waterproof/dustproof structure for a movable mechanism such as a machine tool apparatus or the like, providing a liquid reservoir formed between the inner wall of a stationary member and the outer wall of a movable member at a portion equivalent to the entrance of a gap between the stationary member and the movable member. The leading edge of the movable member moves through a liquid LQ that fills the liquid reservoir. The liquid LQ seals off the interior of the apparatus from the exterior to prevent the entry of mist, dust and other foreign matter. The gap may be made comparatively broad without affecting the ability to prevent the entry of foreign matter. The direction of movement of the movable member may be longitudinal, lateral, reciprocal, rotary, or a combination thereof, depending on the type of movable mechanism to which the waterproof/dustproof structure is applied. The liquid LQ may be a working fluid used by a hydraulic bearing or a machining fluid used by a machine tool.

Abstract: A switching arrangement capable of preventing water from passing through an opening of a cylinder from outside to enter into a casing is disclosed. A switching arrangement includes a switch, a casing in which the switch is accommodated, a cylinder provided on the casing to be opened up and down to be communicated to an interior of the casing, and an operation knob provided to cover the opening of the cylinder, the operation knob being operated to switch the switch on and off, and wherein a step rising toward the cylinder is provided in a position closer to the cylinder than an outer peripheral surface of the operation knob around the cylinder on the casing.