Electricity: electrothermally or thermally actuated switches – Thermally actuated switches – With longitudinally expansible solid element
Reexamination Certificate
2001-11-08
2003-06-24
Vortman, Anatoly (Department: 2835)
Electricity: electrothermally or thermally actuated switches
Thermally actuated switches
With longitudinally expansible solid element
C337S393000, C337S382000, C337S123000, C337S004000
Reexamination Certificate
active
06583711
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a circuit breaker, and more particularly to a temperature sensitive circuit breaker that opens the circuit when a high temperature condition or a current overload exists.
2. Description of Related Art
With reference to
FIG. 6
, a conventional circuit breaker in accordance with the prior art comprises a base (
50
), a core (
53
), two U-shaped rails (
54
), two prongs (
55
), a connector (
60
), a first spring (
64
) and a second spring (
65
). A cavity (
51
) centrally defined in the base (
50
) and extending to the top of the base (
50
). A chamber (
52
) is defined in the base (
50
) and communicates with the cavity (
51
). The core (
53
) is secured in the cavity (
51
) and made of meltable material so that the core (
53
) will melt and the melted material will flow into the chamber (
52
) due to a high temperature caused by a current overload. The U-shaped rails (
54
) are attached perpendicularly to the top of the base (
50
) on diametrically opposite sides of the cavity (
51
). Each rail (
54
) has a slot (not shown) defined in the bottom of the rail (
54
) aligning with and facing the slot in the other rail (
54
). The prongs (
55
) extend through the base (
50
), and part of each prong (
55
) is embedded in tile base (
50
). A convex contact (
551
) is formed on a first end of each prong (
55
) and aligns with the slot in the rail (
54
). A second end of each prong (
55
) is electrically connected to the circuit.
The connector (
60
) is electrically connected between the two prongs (
55
) and comprises two slides (
61
), a bridge (
62
) and a rod (
63
). The slides (
61
) are respectively slidably mounted in the U-shaped rails (
54
). Each slide (
61
) has a first side (not numbered) abutting the contract (
551
) on the prong (
55
) and a second side (not numbered) electrically connected to a bridge (
62
) so that the two prongs (
55
) are electrically connected to each other. The rod (
63
) has a first end attached to the bottom of the bridge (
62
) and a second end securely inserted into the core (
53
). The first spring (
64
) mounted around the rod (
63
) and is compressed between the top of the base (
50
) and the bottom of the bridge (
62
). A second spring (
65
) has first end attached to the top of the bridge (
62
) and a second end attached to the casing (
70
) so the second spring (
65
) is stretched between the bridge (
62
) and the casing (
70
).
With reference to
FIG. 7
, when the circuit (not shown) to which the breaker is attached has a current overload and a resultant high temperature, the core (
53
) melts and flows into the chamber (
52
). This frees the rod (
53
) from the core (
53
), and restitution force in the first and second springs (
64
,
65
) detach the bridge (
62
) from the rail (
54
). Then the circuit to which the breaker is attached is broken because the two prongs (
55
) are disconnected from each other.
The conventional circuit breaker breaks the circuit only when the circuit has a high temperature that is caused by an overload current. However, a current overload does not necessarily cause a high temperature so that the current overload may damage the circuit. Furthermore, the conventional circuit breaker comprises many small elements, such as the rod (
63
) and the two springs (
64
,
65
) that are hard to assemble in the casing (
70
), and conventional circuit breaker can only be used one time because the core (
53
) can not be restored to its original configuration after being melted.
The present invention has arisen to mitigate and/or obviate the disadvantages of the conventional circuit breaker.
SUMMARY OF THE INVENTION
The main objective of the present invention is to provide a simpler circuit breaker that opens the circuit to which it is attached whatever a high temperature or a current overload in the circuit.
To achieve tile objective, the circuit breaker in accordance with the present invention comprises two contacts electrically mounted on a circuit board and an insulating pivot seat attached to the circuit board between the two contacts. A lever has a first end pivotally connected to the pivot seat and connected to one of the contact and a second end electrically connected to the other contact. A non-metallic expansive rod is mounted on the circuit board below the lever to push the lever upwardly to make the second end of lever disconnect from the contact when a high temperature in the circuit is transferred to the expansive rod. A breaking member is connected between a second end of the lever and the other contact on the circuit board. A high temperature associated with a current overload causes the breaking member to melt and open a circuit to which the breaker is attached.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.
REFERENCES:
patent: 661555 (1900-11-01), Ross
patent: 2809523 (1957-10-01), Burling et al.
patent: 3594674 (1971-07-01), Willson
patent: 3634803 (1972-01-01), Willson et al.
patent: 4642599 (1987-02-01), Saur
patent: 5014036 (1991-05-01), Komoto
patent: 5159309 (1992-10-01), Bayer
patent: 5831507 (1998-11-01), Kasamatsu et al.
patent: 2071913 (1981-09-01), None
Dellett and Walters
Vortman Anatoly
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