Electricity: electrothermally or thermally actuated switches – Electrothermally actuated switches – With bimetallic elements
Reexamination Certificate
2000-01-05
2001-10-23
Picard, Leo P. (Department: 2835)
Electricity: electrothermally or thermally actuated switches
Electrothermally actuated switches
With bimetallic elements
C337S039000, C337S059000, C337S008000, C337S112000, C337S113000, C337S066000, C337S074000
Reexamination Certificate
active
06307459
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a switch structure, and more specifically, to a power switch with a simpler structure that 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 and OFF functions 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 users can not be aware of such latent danger since overloading and overheating are invisible. Therefore, such improved power switches have been greatly needed to overcome the danger.
Some improved power switch of 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, the power switch disclosed in in the prior art includes 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 cuts 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, the power switch disclosed in U.S. Pat. No. 5,786,742 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 THE INVENTION
An object of the present invention is to provide a switch structure comprising a control element, which consists of an alloy piece and a swing contact device. The alloy piece includes an actuating piece with a convex part, which has a upper side normally pushing the lower surface of the end part in the swing contact device so that the actuating piece ejects outwards and escapes from the end part when the alloy piece is overheated because the current flowing through the alloy piece is overloaded. Therefore, the end part falls down due to no support force and the head part of the swing contact device deforms upwards and does not press on the elastic contact piece. The elastic contact piece is released from the pressing of the swing contact device to eject upwards. Two joints connected in an electric loop are tripped. The object of rapid response, cutting power source, and safety is therefore achieved.
Other features and advantages of the invention will become apparent from the following description of the invention that 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), Andersen
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.
Vortman Anatoly
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