EP2760036A1 - Waterproof and dust protected switch - Google Patents

Abstract

[Problem] To provide a waterproof and dust protected switch having superior shape retention characteristics, durability, and operating stability. [Solution] This waterproof and dust protected switch (SW) is provided with a switch mechanism unit (1) that switches contacts by the operation of an outside force and a switch case (2) that protects the switch mechanism unit (1). The switch case (2) is constituted of a case main body (7) formed from a hard material that accommodates the switch mechanism unit (1) and a cover (9) that covers the case main body (7) and is formed from a soft material. The case main body (7) and cover (9) are integrated by two-color molding, and also a reinforcing rib (8) is provided integrated with the case main body (7) or separately on a part where the outside force operates on the cover (9).

Description

Technical Field
• The present invention relates to a waterproof and dust protected switch used as a power supply switch in electronic devices such as, for example, electronic book terminals, mobile phone devices, etc., capable of preventing the intrusion of water drops, dust, etc. particularly into a switch mechanism unit or the inside of electronic devices.
Background of the Invention
• Heretofore, a waterproof switch applied by the present applicant in the past is known as a switch comprising characteristics such as those described above (refer to following Patent Document 1). In this waterproof switch, the switch main body part is accommodated within a switch case with a two-layer structure comprising a waterproof cover and a case body, molded with two colors on the outer surface thereof. Furthermore, regarding the switch case, part of the waterproof cover is projected from the outer surface of the case body in a dome shape, with a knob of the switch main body part arranged inside the dome. Therefore, because the knob of the switch main body is completely covered by the dome which is a part of the waterproof cover, this waterproof switch is capable of preventing water from entering the switch case from the periphery of the knob.
Prior Art DocumentPatent Documents
• Patent Document 1: Japanese Unexamined Patent Application Publication2005-209527
Summary of the InventionProblems to be solved by the Invention
• Incidentally, in the waterproof switch ofPatent Document 1, when the knob is pressed, the dome making up part of the waterproof cover is supposed to stretch integrally with the knob. For this reason, in order to maintain the stretching properties of the dome, the thickness of the resin constituting the dome has to be molded thinner than other portions of the waterproof cover (refer toFig. 1 orFig. 7 of Patent Document 1). Therefore, there has been a problem in that after repetitive pressing operations of the knob, wear and tear, etc. is generated in the resin of the thin portion of the dome, rendering the switch operation no longer stable.
• The present invention is designed to solve such problems with the purpose of providing a waterproof and dust protected switch capable of preventing the intrusion of water drops or dust, etc. into the switch case without fail and maintaining stable switch operations for a long period of time by enhancing durability.
Means for Solving the Problems
• In order to achieve said purpose, the waterproof and dust protected switch in the present invention is provided with a switch mechanism unit that switches contacts by the operation of outside force along with a switch case that protects said switch mechanism unit. Said switch case is constituted of a case main body formed from a hard material that accommodates said switch mechanism unit and a cover that covers said case main body and is formed from a soft material. Said case main body and said cover are integrated by two-color molding, and a reinforcing rib is also provided integrally with said case main body or separately on the part where outside force operates on said cover.
• In the waterproof and dust protected switch in the present invention, it is possible for said switch case to adopt a configuration in which a plate spring is formed by the top plate of said case main body and said reinforcing rib inclining with respect to the top plate.
• Furthermore, in the waterproof and dust protected switch in the present invention, regarding said switch case, when outside force acts on said cover, said reinforcing rib is preferably arranged at a position to press the operation body of said switch mechanism unit.
• Moreover, in the waterproof and dust protected switch in the present invention, it is possible to adopt a configuration for said switch case such that said case main body is formed from polyamide resin and said cover is formed from silicon rubber.
• Furthermore, in the waterproof and dust protected switch in the present invention, a configuration of a lever switch that switches contacts by an inclining movement of the lever may also be adopted for said switch mechanism unit.
Effects of the Invention
• According to the waterproof and dust protected switch in the present invention, the switch is configured such that the case main body and the cover are integrated by two-color molding and the cover is tightly attached to the case main body so as to completely close the switch mechanism unit, providing an effect of preventing the intrusion of water drops or dust from outside so as to protect the switch mechanism unit without fail. Furthermore, a reinforcing rib is provided integrally or separately with respect to the case main body at the location in which outside force acts on the cover, further providing an effect such that the shape retention characteristics may favourably be maintained without causing wear and tear, etc. on the cover as a result of repetitive use and smooth and stable operations may be realized for a long period of time with excellent durability.
Brief Description of the Drawings
• [Fig. 1] depicts the outer appearance of the waterproof and dust protected switch inEmbodiment 1, in which (a) is a plane drawing and (b) is the front view.
• [Fig. 2] is an exploded cross-section drawing of the waterproof and dust protected switch inFig. 1.
• [Fig. 3] depicts a base consisting of the waterproof and dust protected switch inFig. 1, in which (a) is a plane drawing before being cut, (b) is the front view, (c) is a cross-section drawing along A-A, (d) is a right side section drawing, (e) is a cross-section drawing along B-B, and (f) is a plane drawing after being cut.
• [Fig. 4] depicts a contact pattern consisting of the waterproof and dust protected switch inFig. 1, in which (a) is a plane drawing, (b) is the front view, and (c) is a cross-section drawing along A-A.
• [Fig. 5] depicts a lever consisting of the waterproof and dust protected switch inFig. 1, in which (a) is a plane drawing, (b) is a right side section drawing, (c) is the front view, (d) is a cross-section drawing along A-A, and (e) is the front view of a state in which a contact spring piece has been fit in.
• [Fig. 6] depicts the state at the time of primary molding of a switch case consisting of the waterproof and dust protected switch inFig. 1, in which (a) is a plane drawing, (b) is the front view, (c) is a cross-section drawing along A-A, (d) is a right side section drawing, (e) is a cross-section drawing along B-B, and (f) is a cross-section drawing along C-C.
• [Fig. 7] depicts the state at the time of secondary molding of the switch case consisting of the waterproof and dust protected switch inFig. 1, in which (a) is a plane drawing, (b) is the front view, (c) is a cross-section drawing along A-A, (d) is a right side section drawing, and (e) is a cross-section drawing along B-B.
• [Fig. 8] depicts a still state of the waterproof and dust protected switch inFig. 1, in which
  1. (a) is the outer appearance and (b) is a cross-section drawing.
• [Fig. 9] depicts the operation state of the waterproof and dust protected switch inFig. 1, in which (a) is the outer appearance and (b) is a cross-section drawing.
• [Fig. 10] depicts the outer appearance of a waterproof and dust protected switch according toEmbodiment 2, in which (a) is a plane drawing and (b) is the front view.
• [Fig. 11] depicts the state at the time of primary molding of the switch case consisting of the waterproof and dust protected switch ofFig. 10, in which (a) is a plane drawing, (b) is the front view, (c) is a cross-section drawing along A-A, (d) is a right side section drawing, (e) is a cross-section drawing along B-B, and (f) is a cross-section drawing along C-C.
• [Fig. 12] depicts the state at the time of secondary molding of the switch case consisting of the waterproof and dust protected switch ofFig. 10, in which (a) is a plane drawing, (b) is the front view, (c) is a cross-section along A-A, (d) is a right side section drawing, and (e) is a cross-section drawing along B-B.
Detailed Description of the Invention
• Hereinafter, embodiments for implementing the present invention are described with reference to the drawings.
• As depicted inFig. 1, waterproof and dust protected switch SW in the present embodiment is a small size switch that can be used as a power supply switch for electronic devices such as, for example, electronic book terminals, mobile phones, etc. This switch is characterized in that a waterproof and dust protected structure is adopted forswitch case 2 in order to prevent the intrusion of water drops, dust, etc. into internalswitch mechanism unit 1 or an electronic device main body at the time of usage. It should be noted that the power supply switch that is shown as an example is merely one example and the present invention is applicable in other switches used for environments in which waterproof properties or dust protective properties are required.
• As exploded and depicted inFig. 2, waterproof and dust protected switch SW comprisesswitch mechanism unit 1 andswitch case 2.Switch mechanism unit 1 switches contacts by operating an outside force (for example, by pressing with a finger) and a lever switch that switches contacts via an inclining operation oflever 5 which makes up an operation body is adopted in the present embodiment.Switch case 2 protectsswitch mechanism unit 1 and is structured so as to completely encapsulate the internalswitch mechanism unit 1 by a double structure comprising casemain body 7 andcover 9 in the present embodiment.
• Herein, the structure ofswitch mechanism unit 1 is described.Fig. 3 depictsbase 3 constitutingswitch mechanism unit 1.Base 3 is molded from a resin material that has insulating properties (polyamide resin in the present embodiment), whilespace 31 for internally accommodating parts in a flat box-shaped main body is provided mounted on a substrate.Concave part 32 for installinglever 5 to be described later is formed on the front and back surfaces of the main body, whileseat 33, which is one step higher, is formed on the inner bottom surface of the main body. Furthermore, lockingpawls 34 for attachingswitch case 2 to be described later are provided on the external wall surface of the main body.
• Fig. 4 depicts acontact pattern 4 constitutingswitch mechanism unit 1.Contact pattern 4 is formed by punching out a metal sheet (phosphor bronze plate in the present embodiment) having conductive properties and comprises two rows offixed contacts 41, 42 arranged in the center thereof with a predetermined interval in between. Furthermore, each offixed contacts 41, 42 is provided with fourconnection terminals 43, 43, bent like a stair so as to be one step lower.
• Regarding thiscontact pattern 4, by insertion molding at the time ofmolding base 3 as depicted inFig. 3, two rows offixed contacts 41, 42 are fixed onto the inner bottom surface ofbase 3, while fourconnection terminals 43, 43, connected tofixed contacts 41, 42, are formed outsidebase 3 in a projected manner. It should be noted that after insertion molding, the two rows offixed contacts 41, 42 are brought into a state such that they are separated from each other as depicted inFig. 3 (f) by cut processing the dotted portion indicated inFig. 3 (a).
• Fig. 5 depictslever 5 that constitutesswitch mechanism unit 1.Lever 5 is molded from resin material (polyamide resin in this embodiment) that has insulating properties and comprisesoperation part 51 to receive an outside force,holder part 52 for holdingcontact spring piece 6, andcam part 53 for transmitting the outside force to contactspring piece 6. As depicted inFig. 5 (e), in thislever 5,contact spring piece 6 is fit intoholder part 52 such that it is fixed while being in an energy accumulated state. With regard tocontact spring piece 6, a metal piece is bent into a U-shape providing resilient power and the end part thereof is divided into two to form a pair of leg parts, with the tip ends thereof becoming independentmovable contacts 61, 62, respectively. As depicted inFig. 2, byinserting shaft part 54 provided on the outer wall surface intoconcave part 33 ofbase 3,lever 5, onto which thiscontact spring piece 6 has been fixed, is rotatably supported byshaft part 54 which is a fulcrum point.
• Next, the structure ofswitch case 2 is described.Fig. 6 andFig. 7 depictswitch case 2 following molding steps.Switch case 2 has a double structure consisting of casemain body 7 that is molded in the primary molding as depicted inFig. 6 andcover 9 that is molded in the secondary molding as depicted inFig. 7.
• As depicted inFig. 6, casemain body 7 is formed from a hard material that has insulating properties (polyamide resin in the present embodiment) and is molded into a flat box shape as depicted in the figure by heating, melting, and injection molding the hard material. This casemain body 7 is for protectingswitch mechanism part 1 by coveringbase 3, for whichspace 71 for accommodatinglever 5 inside the main body is provided and openingpart 73 for insertinglever 5 therein is formed intop plate 72 on the upper surface of the main body. Attachingpiece 74 for securing purposes is provided onbase 3 on the front and back surfaces of the main body, while lockinghole 75 to be fitted with lockingpawl 34 ofbase 3 is formed in attachingpiece 74.
• Furthermore, reinforcingrib 8 made from the same hard material as casemain body 7 is provided as frame ofcover 9. As depicted inFig. 6 (b) (c), reinforcingrib 8 is arranged in an inclining state with respect totop plate 72 of casemain body 7, while reinforcingrib 8 andtop plate 72 constituteplate spring part 81 that has resilient force. Moreover, as depicted inFig. 6 (d) (e) (f), two rows ofprojection parts 82, 82 molded in the same mountain shape aslever 5 are provided at one end of reinforcingrib 8. Furthermore,round hole 83 for securing a contact area withcover 9 is provided at the other end of reinforcingrib 8 as depicted inFig. 6 (a) (c). It should be noted that reinforcingrib 8 is provided as a separate body from casemain body 7 in the present embodiment; however, alternatively, reinforcingrib 8 may also be provided integrally by connecting totop plate 72 of casemain body 7.
• As depicted inFig. 7,cover 9 is made from a soft material (silicon rubber in the present embodiment) that has insulating properties such as elastomar resin, etc. and is molded into a dome shape withcavity 91 inside thereof as illustrated, by heating, melting and injection molding the soft material. During the molding step, first, a die is opened after molding casemain body 7 and only the top mold is replaced with a top mold for cover molding (reinforcingrib 8 has been set within the mold) subsequently followed by clamping the mold. Thereafter, liquid silicon rubber is injected into the die and finally cooled to harden. As described, by two-color molding with a hard material (polyamide resin) and a soft material (silicon rubber), switchcase 2 is molded with casemain body 7 andcover 9 integrated.
• As depicted inFig. 8, two-color moldedswitch case 2 is mounted onbase 3 wherelever 5 has been installed.Switch case 2 covers overbase 3, andbase 3 as well asswitch case 2 are secured by hooking lockingpawl 34 ofbase 3 into lockinghole 75 of casemain body 7 as in the drawing.
• Becausecover 9 covering over casemain body 7 is integrated by two-color molding,cover 9 is closely attached to casemain body 7 and saidswitch case 2 is capable of completely blocking the intrusion of water drops or dust from outside. Furthermore, regarding the locations at which an outside force acts, reinforcingrib 8 made from a hard material is bonded to cover 9 that is made from a soft material, significantly enhancing the performance of shape retention characteristics, durability, operating stability, etc. ofcover 9. Furthermore, as inFig. 7 (c), siliconrubber composing cover 9 is inserted intoround hole 83 of reinforcingrib 8 and, as inFig. 7 (d) (e),projection part 92 formed from silicon rubber that constitutescover 9 is also inserted between two rows ofprojection parts 82 and 82 at the tip end of the reinforcing rib so as to be bonded. Thereby, the contact area of casemain body 7 andcover 9 is largely ensured, further enhancing the bonding properties of both.
• Finally, the operations of waterproof and dust protected switch SW in the present embodiment will be described. In the still state depicted inFig. 8,shaft part 54 oflever 5 is sandwiched betweenconcave part 32 ofbase 3 andtop plate 72 of casemain body 7 to prevent it from coming off, whileoperation part 51 oflever 5 is projected from openingpart 73 of casemain body 7. Furthermore, projectedoperation part 51 is accommodated withinspace 71 of casemain body 7 and arranged at the opposite position facing reinforcingrib 8 that comprisesplate spring part 81. At this time, onemovable contact 61 ofcontact spring piece 6 is in contact withfixed contact 41, but the othermovable contact 62 is not in contact withfixed contact 42. For this reason, fixedcontacts 41 and 42 are not conductive to each other and the switch is in an OFF state.
• On the other hand, in the operation state depicted inFig. 9, whenprojection part 92 ofcover 9 is pressed with a finger, etc. theentire cover 9 made from silicon rubber sinks resulting in deformation, compressingplate spring part 81 of reinforcingrib 8 that has been integrated intocover 9. Herein, when the compressedplate spring part 81presses operation part 51 oflever 5 andlever 5 rotates withshaft 54 as a fulcrum and falls,operation part 51, upon which an outside force is received, thereby functions as the stress point andcam part 53 abuttingcontact spring piece 6 as the operating point. At this time,contact piece 6 is pressed bycam part 53 and compressed, while the othermovable contact 62 comes into contact withfixed contact 42. Consequently, fixedcontacts 41 and 42 become conductive to each other viacontact spring piece 6, switching the state of the switch to ON.
• It should be noted that when the pushing power is released by removing the finger,lever 5 that has fallen is lifted up by the resilient returning force ofcontact spring piece 6. Furthermore, accompanying this,cover 9 that has been sunk is also lifted up to the original position by the resilient returning force ofplate spring part 81. Thereby, the othermovable contact 62 ofcontact spring piece 6 moves away from fixedcontact 42 and the conductivity between fixedcontacts 41 and 42 is cut off, switching the state of the switch to OFF.
• As described, according to waterproof and dust protected switch SW of the present embodiment, not only is the intrusion of water drops or dust from outside prevented, but the shape retention characteristics ofcover 9 may also be favourably maintained without generating wear and tear after repetitive use by bonding and integrating reinforcingrib 8 that is made from a hard material andcover 9 that is made from silicon rubber. Furthermore,projection part 92, upon which an outside force acts, is protected by being sandwiched bythick projection part 82 made from a hard material, providing excellent durability. It should be noted thatcover 9 made from silicon rubber is provided with a stair-like step 93 which acts as a trigger point of the cavity when pressed with a finger and is easily deformed while giving strength thereto, allowing smooth and stable operations to be realized for a long period of time.
• It should be noted that in said embodiment, casemain body 7 and reinforcingrib 8constituting switch case 2 are separate bodies; however, alternatively, casemain body 7 and reinforcingrib 8 may also be provided as one body. In the waterproof and dust protected switch SW depicted inFig. 10,switch case 2 is configured as a double structure consisting of casemain body 7 that is molded in the primary molding depicted inFig. 11 andcover 9 that is molded in the secondary molding depicted inFig. 12.
• As depicted inFig. 11, in the present embodiment, reinforcingrib 8 is connected totop plate 72 of casemain body 7 that is made of a hard material (polyamide resin in the present embodiment) and the connected portion thereof constitutesplate spring part 81 that has resilient force. As described inFig. 12, dome-shapedcover 9 comprisingcavity part 91 therein is molded by heating, melting, and injection molding a soft material such as elastomer resin, etc. (silicon rubber in the present embodiment). As described, switchcase 2 with integrated casemain body 7 andcover 9 is configured by two-color molding of a hard material (polyamide resin) and a soft material (silicon rubber).
• Also in the waterproof and dust protected switch SW in the present embodiment,cover 9 is closely attached to casemain body 7 that constitutes switchcase 2, enabling the protection ofswitch mechanism unit 1 without fail by completely blocking the intrusion of water drops or dust, etc. from outside. Furthermore, particularly in the present embodiment, because casemain body 7 and reinforcingrib 8 are connected and the connected portion constitutesplate spring 81, the compressing and resilient returning operations ofplate spring 81 are conducted smoothly, making it possible to realize favourably responsive and stable switch operations as an advantageous point.
• In the embodiments described thus far, although a lever switch is adopted asswitch mechanism unit 1 constituting waterproof and dust protected switch SW, switches in other structures such as a push switch or a sliding switch, etc. may also be adopted without being limited to this. Furthermore, also with regard to casemain body 7 andcover 9constituting switch case 2, the shape and the material are not necessarily limited to the above embodiment, with appropriate modifications possible within the normal creative capability of those in the industry within the scope of of the present invention.
Explanation of the Symbols
• SW...waterproof and dust protected switch
  • 1... switch mechanism unit
  • 2... switch case
  • 3...base
    • 31...space
    • 32... concave part
    • 33...seat
    • 34...locking pawl
  • 4...contact pattern
    • 41... fixed contact
    • 42... fixed contact
    • 43...connection terminal
  • 5...lever
    • 51...operation part
    • 52...holder part
    • 53...cam part
    • 54...shaft part
  • 6... contact spring piece
    • 61...movable contact
    • 62...movable contact
  • 7...case main body
    • 71... space
    • 72...top plate
    • 73... opening part
    • 74...attaching piece
    • 75...locking hole
  • 8...reinforcing rib
    • 81...plate spring part
    • 82...projection part
    • 83...round hole
  • 9... cover
    • 91... cavity
    • 92...projection part
    • 93...step

Claims (5)

1. A waterproof and dust protected switch, comprising a switch mechanism unit that switches contacts by the operation of an outside force, and
   a switch case that protects said switch mechanism unit, wherein
   said switch case comprises:

   a case main body formed from a hard material for accommodating said switch mechanism unit; and

   a cover formed from a soft material covering said case main body, and

   said case main body and said cover are integrated by two-color molding and a reinforcing rib is provided integrally or separately with respect to said case main body for a portion of said cover upon which outside force acts.
2. The waterproof and dust protected switch according to claim 1, wherein said switch case has a plate spring formed by the top plate of said case main body and said reinforcing rib inclining with respect to the top plate.
3. The waterproof and dust protected switch according to claim 1 or 2, wherein, in said switch case, when an outside force acts on said cover, said reinforcing rib is arranged at a location to press the operation body of said switch mechanism.
4. The waterproof and dust protected switch according to any one of claims 1 through 3, wherein, in said switch case, said case main body is formed from polyamide resin and said cover is made from silicon rubber.
5. The waterproof and dust protected switch according to any one of claims 1 through 4, wherein said switch mechanism unit is a lever switch that switches contacts via the inclining operation of the lever.

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