Contact structure
The present invention provides a means in which contact between contacts in a “double-break (or double-make) contact structure” occurs in two places in the same state as much as possible. A contact structure includes two fixed members ( 110,112 ) each of which has a fixed contact ( 116,118 ) and a movable member ( 102 ) containing a movable contact ( 106 ) which contacts or separates from the fixed contact of each of the fixed members. The movable member is in the form of a strip as a whole, its one end is supported so as to allow the above mentioned contact and separation of the movable member, and the other end of the movable member has the movable contact, and the movable member has a narrowed section between its two ends.
1. A circuit protection device which comprises a contact structure, said contact structure comprising two fixed members each of which has a fixed contact, and a movable member comprising a movable contact which contacts or separates from the fixed contact each fixed member, which structure is characterized in that:
the movable member is in the form of a strip as a whole having edges along a length and a width between the edges, its one end is supported so as to allow said contacting and separating of the movable member, and the other end of the movable member has the movable contact,
the movable member has a narrowed section between its two ends, said narrowed section having a width that is 0.3 to 0.6 times a width of the movable member and is formed such that the width of the movable member recedes by the same distance from the edges, and
the circuit protection device comprises a circuit switching member comprising a bimetal component as a circuit switching element and a movable terminal having the movable contact, and a PTC component.
2. The circuit protection device according to claim 1 characterized in that
(1) the PTC component and the movable terminal are electrically connected in parallel;
(2) the circuit switching member is able to interrupt a current flowing through the circuit switching member by moving the movable terminal which is disposed to pass the current so as to separate the movable contact from the fixed contacts by means of actuation of the bimetal component at its actuating temperature (Top), and is also able to pass the current through the circuit switching member by contacting the movable contact with the fixed contacts through moving the movable terminal which is disposed to interrupt the current by means of resetting of the bimetal component at its reset temperature (Tcl), and
(3) the bimetal component is disposed between the PTC component and the movable terminal.
3. An electrical apparatus which comprises a circuit protection device, said circuit protection device comprising a contact structure, said contact structure comprising two fixed members each of which has a fixed contact, and a movable member comprising a movable contact which contacts or separates from the fixed contact each fixed member, which structure is characterized in that
the movable member is in the form of a strip as a whole having edges along a length and a width between the edges, its one end is supported so as to allow said contacting and separating of the movable member, and the other end of the movable member has the movable contact, and
the movable member has a narrowed section between its two ends, said narrowed section having a width that is 0.3 to 0.6 times a width of the movable member and is formed such that the width of the movable member recedes by the same distance from the edges,
wherein the circuit protection device comprises a circuit switching member comprising a bimetal component as a circuit switching element and a movable terminal having the movable contact, and a PTC component.
4. The circuit protection device of claim 1 wherein the contact structure is a double-break or double-make contact structure.
5. The electrical apparatus of claim 3 wherein
(1) the PTC component and the movable terminal are electrically connected in parallel;
(2) the circuit switching member is able to interrupt a current flowing through the circuit switching member by moving the movable terminal which is disposed to pass the current so as to separate the movable contact from the fixed contacts by means of actuation of the bimetal component at its actuating temperature (Top), and is also able to pass the current through the circuit switching member by contacting the movable contact with the fixed contacts through moving the movable terminal which is disposed to interrupt the current by means of resetting of the bimetal component at its reset temperature (Tcl), and
(3) the bimetal component is disposed between the PTC component and the movable terminal.
6. The electrical apparatus of claim 3 wherein the contact structure is a double-break or double-make contact structure.