1. Field of the Invention
The present invention relates to a sealed pushbutton switch, and particularly to a normally closed sealed pushbutton switch used in various electronic appliance.
2. Description of Related Art
A conventional sealed pushbutton switch is described in U.S. Pat. No. 6,459,057, which was issued on Oct. 1, 2002. The pushbutton switch is normally in a closed position, comprising a base, a plurality of fixed contacts assembled to the base, an insulative housing snapping onto the base, an actuator retained in the insulative housing and provided with a shaft and a head, a contact spring normally contactable of an inner edge of fixed contacts for establish an engagement between the contact spring and the fixed contacts, a wire compression spring abutting against a bottom of the head, and an O-ring mounted around the shaft. In operation, the actuator is pushed downwardly to thereby move the contact spring away from the fixed contacts for breaking the electrical connection between the fixed contacts. The pushbutton switch is then caused to be in an electrical opened position.
An electrical connection between the fixed contacts is established by an engagement between the contact spring and inner edges of the fixed contacts. However, the engagement between the contact spring and the fixed contacts is unreliable, not only because an out surface of the contact spring is discrete, but also because the inner edge of the fixed contact is narrow. Further more, the contact spring is moveably retained in the head of the actuator. As a result, the contact spring is hard to be availably driven by the actuator thus is hard to have a steady engagement with the fixed contacts.
Hence, an improved pushbutton switch is required to overcome the above-mentioned disadvantages of the related art.
A primary object of the present invention is to provide a sealed pushbutton switch having a moveable contact and a fixed contact, between which a reliable engagement is established.
Another object of the present invention is to provide a sealed pushbutton switch formed with a moveable contact having an agile movement during operation.
Another object of the present invention is to provide a sealed pushbutton switch provided with a moveable contact capable of being availably driven by the actuator.
To achieve the aforementioned objects, a sealed pushbutton switch comprises an insulative housing defining a cavity, a plurality of fixed contacts mounted on the insulative housing each formed with an engaging portion, an actuator moveably retained in the insulative housing, a moveable contact fastened to the actuator and comprising a pair of elastic beams each provided with a contact portion contactable to corresponding engaging portions of the fixed contacts, and a spring mounted below the actuator. When the actuator is pressed and moves together with the moveable contact from a first position to a second position relative to the insulative housing along a top-to-bottom direction, an electrical connection between the moveable contact and the fixed contacts comes to break.
The moveable contact comprising a pair of elastic beams each provided with a contact portion would not only get a reliable engagement between itself and the fixed contacts, but also have an agile movement of moving away from the fixed contacts when it is caused to be in electrical opened position.
Additionally, another advantage of the invention is to provide an engaging portion on each fixed contact for enlarging contacting area between the moveable contact and the fixed contact. The engagement between the moveable contact and the fixed contacts is enhanced.
Further more, the moveable contact fastened to the actuator would make itself unmovable relative to the actuator to have a reliable operation together with the actuator. The actuator would have an available manipulation to drive the moveable contact in operation.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of a preferred embodiment when taken in conjunction with the accompanying drawings.
Reference will now be made to the drawing figures to describe the present invention in detail. Referring to
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Thirdly, the pair of fixed contacts 7 are assembled to the base 8. The body portions 71 of the fixed contacts 7 are respectively partially retained in corresponding retaining channels 841, with engaging portions 711 thereof being exposed on the inner face 11, the connection portions 72 thereof inserted into the corresponding insertion channels 142, and the soldering portions 74 thereof extending outwardly through the insertion channels 142. Finally, the base 1 together with the fixed contacts 7 are attached to a rear portion of the insulative housing 2. Referring to
In operation, when the button 31 of the actuator 3 is downwardly pushed due to an external force exerted thereon, the moveable contact 6 is driven to move downwardly together with the actuator 3 to thereby make the contact portions 621 moving away from the engaging portions 711 and plunging into the indentations 73. The sealed pushbutton switch 1 is caused to be in an electrical opened position, when the electrical connection between the engaging portions 711 of the fixed contacts 7 is broken. At the same time, the spring 5 is compressed. When the external force is removed, the pushbutton switch 1 restores itself to a normally closed position, due to an elastic force provided by the compressed spring 5.
In another embodiment, the fixed contacts 7 could be assembled to the walls 21-24 of the insulative housing 2, with the engaging portions 711 thereof exposed to the cavity 25 for being contacted by the moveable contact 6.
However, the disclosure is illustrative only, changes may be made in detail, especially in matter of shape, size, and arrangement of parts within the principles of the invention.
Number | Date | Country | Kind |
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2005 2 00785308 | Sep 2005 | CN | national |
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Number | Date | Country | |
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20070051602 A1 | Mar 2007 | US |