Electricity: electrothermally or thermally actuated switches – Electrothermally actuated switches – With bimetallic elements
Reexamination Certificate
1999-11-10
2001-06-26
Picard, Leo P. (Department: 2835)
Electricity: electrothermally or thermally actuated switches
Electrothermally actuated switches
With bimetallic elements
C337S039000, C337S059000, C337S085000, C337S112000, C337S113000, C337S066000, C337S074000
Reexamination Certificate
active
06252489
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a switch structure, and more specifically, to a power switch with a simpler structure which is capable of switching off the power source when the current is overloaded.
BACKGROUND OF THE INVENTION
Power switches with only two states of ON/OFF function controlled manually have been widely used in many appliances. However, it is risky to use the above power switches when the power source is unstable because overheating may occur due to overloading of the appliance and the wire easily catches fire. The user can not be aware of such latent danger since overloading and overheating are invisible. Therefore, improved power switches have been greatly needed to overcome the danger.
Some improved power switches in the prior arts includes an alloy element composed of more than one metal to automatically shut off the power source when the alloy element is thermally deformed because of overheating.
For example, a conventional power switch comprises an alloy piece, a lever, and a cam actuator. The lever is actuated by the alloy piece, and the cam actuator is used to coordinate with a seesaw actuator. Thermal deformation of the alloy piece causes the lever to move, and then the cam actuator loses support, escapes and further shuts off the power source. Overheating may occur on he alloy piece. The above power switch uses the lever, the cam actuator, and the seesaw actuator to indirectly control the conductive plate, which is used to contact with the power source. The response of the power off operation in the above power switch when overheating occurs is so slow that the overloaded current may flow into the operating appliance in a short time to damage the appliance. Additionally, the conductive plate and the alloy piece need the wire to connect to each other, and the whole structure is complicated to cause the manufacturing difficult. The alloy piece has to actuate the seesaw actuator and the lever to escape. The function of automatic power off may incorrectly operate.
Furthermore, another conventional power switch uses the thermal deformation of the alloy piece to push a limited position base such that a button can automatically escape and return back. The button is used to directly contact with the contact point of the power source so that the button may conduct the overloaded current when overheating occurs. The whole structure is still complicated. In summary, those improved power switches in the prior arts can partly overcome the danger of overheating for the appliance but the response is slow and the whole structure is complicated. An advanced power switch with simpler structure and a short response time is greatly desired.
SUMMARY OF THF INVENTION
An object of the present invention is to provide a power switch, which consists of an alloy piece, a contact control device, and a push device. The contact control device includes an elastic part and connects to an end part so that the end part may reciprocally move with respect to the contact control device in a horizontal direction. The end part normally contacts with the upper side of the stopper placed in the switch body and is used to push the push device towards the end part when the alloy piece is overheated and strain is generated due to the current flowing through the alloy piece. The end part then elastically contracts and escapes from the stopper to fall down so that another end of the contact control device projects upwards and does not press the elastic contact plate. Therefore, the elastic contact plate may escape from the two contact points to shut off the power source rapidly by the elastic force to achieve the purpose of safety.
Other features and advantages of the invention will become apparent from the following description of the invention which refers to the accompanying drawings.
REFERENCES:
patent: 3358099 (1967-12-01), Bellomayre
patent: 4258349 (1981-03-01), Flory
patent: 4345233 (1982-08-01), Matthies
patent: 4528538 (1985-07-01), Anderson
patent: 4931762 (1990-06-01), Fierro
patent: 5012495 (1991-04-01), Munroe et al.
patent: 5262748 (1993-11-01), Tsung-Mou
patent: 5451729 (1995-09-01), Onderka et al.
patent: 5541569 (1996-07-01), Jang
patent: 5760672 (1998-06-01), Wang
patent: 5828284 (1998-10-01), Huang
patent: 5847638 (1998-12-01), Sorenson
patent: 5889457 (1999-03-01), Hsu et al.
patent: 5892426 (1999-04-01), Huang
patent: 5898355 (1999-04-01), Yu
patent: 6072381 (2000-06-01), Yu
patent: 6094126 (2000-07-01), Sorenson
patent: 6121868 (2000-09-01), Chiang
patent: 6154116 (2000-11-01), Sorenson
patent: 647094-A5 (1984-12-01), None
patent: 19534611-A1 (1996-03-01), None
patent: 0694947-A1 (1996-01-01), None
Picard Leo P.
Tsung-Mou Yu
Vortman Anatoly
LandOfFree
Switch structure does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Switch structure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Switch structure will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2494238