The present invention relates to a protection mechanism for a switch device and includes a push member which is pivotable so as not to interrupt the deformation of the bimetallic plate when there is electrical current overload.
The conventional circuit breaker uses a fuse between the switch and the circuit so that when there is electrical overload, the fuse will first melt before the overload causes damages. However, if the fuse is not properly installed or an improper fuse is used, the overload current cannot melt the fuse and may result in a disaster. U.S. Pat. Nos. 5,262,748, 4,167,720, 4,937,548, 5,223,813, 5,451,729, and 5,558,211 disclose different types of circuit breakers which commonly include a complicated mechanism to drive the bimetallic plate which is expected to be deformed and bent when there is current overload. Nevertheless, it is noted that the bimetallic plate may not be completely deformed as desired because it is not possible to be freely deformed, and the bimetallic plate is still in contact with the terminal so that sparks may be generated and therefore cause disaster.
Therefore, it is desired to have a protection mechanism for a switch device wherein a pivotable push member pushes the bimetallic plate downward to set the switch device in an “ON” status and the push member is pivoted away form the bimetallic plate to allow the bimetallic plato to be completely deformed when there is current overload.
In accordance with an aspect of the present invention, there is provided a switch device that comprises a case having an open top for a switch member pivotably engaged therewith. A first terminal and a second terminal respectively extend through a bottom of the case. A bimetallic plate has a first end fixed to the first terminal and a first contact point is connected to a second end of the bimetallic plate. A second contact point is connected to the second terminal and located beneath the first contact point. A protection mechanism includes a pull member which has an upper end thereof pivotably connected to the connection port of the switch member. A second end of the bimetallic plate is located above a lower hook end of the pull member so that the bimetallic plate can be lifted by the pull member. A push member is located above the bimetallic plate and pivotably connected to the pull member. The push member is in contact with the second end of the bimetallic plate at an angle when the switch member is pivoted to “ON” status.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
Referring to the drawings and in particular
A protection mechanism including a pull member 41, which has a first rod 412 on an upper end thereof and the first rod 412 is pivotably inserted in the hole 22 in the connection port 21 of the switch member 2. A lower hook end 411 is connected to the lower end of the pull member 41 and the second end of the bimetallic plate 3 is located above the lower hook end 411 of the pull member 41. A push member 42 has a ring 421 located at a top end thereof and the pull member 41 includes a second rod 413 located between the first rod 412 and the lower hook end 411, such that the second rod 413 is inserted through a hole 4210 of the ring 421 of the push member 42. The push member 42 is located above the bimetallic plate 3 and includes an extension portion 422 at a lower end thereof. The extension portion 422 is movably engaged with the inclined surface 131 of the block 13.
A torsion spring 23 has a circle portion at an intermediate portion thereof which is mounted to the first protrusion 14. A first end 231 of the torsion spring 23 biases against the underside of the switch member 2 and a second end 232 of the torsion spring 23 contacts the second protrusion 15 so that the first end 231 of the torsion spring 23 provides an upward force to the underside of the switch member 2 to keep the switch member 2 at its “OFF” status
A base is connected to an inside of the case 1 and an adjusting bolt 34 is threadedly connected to the base. A curve flexible plate 33 has a notch 332 defined in a first end thereof and the adjusting bolt 34 is engaged with the notch 332. A second end of the flexible plate 33 includes a tongue 331 that is engaged with a through hole 32 of the second end of the bimetallic plate 3. The flexible plate 33 provides a force to assist the deformation of the bimetallic plate 3.
When pressing the right end of the switch member 2 as shown in
As shown in
While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.
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5451729 | Onderka et al. | Sep 1995 | A |
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6822179 | Huang | Nov 2004 | B1 |
Number | Date | Country | |
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20060006979 A1 | Jan 2006 | US |