High-amp circuit breaker and a bistable element therefor

• US 5,021,761 A
• Filed: 09/28/1989
• Issued: 06/04/1991
• Est. Priority Date: 09/28/1989
• Status: Expired due to Term

• Current Assignee: Cooper Bussmann Incorporated (Eaton Corporation PLC.)
• Original Assignee: Cooper Industries, Inc. (Eaton Corporation PLC.)
• Inventors: Korczynski, Jacek M., Stack, Thomas J.
• Primary Examiner(s): BROOME, HAROLD
• Application Number:
  US07/414,095
• Time in Patent Office: 614 Days
• Field of Search: 337/68, 337/91, 337/111, 337/379, 337/365, 337/89
• US Class Current: 337/68
• CPC Class Codes: H01H 73/24 reset by lever
• CPC Class Codes: H01H 73/303 with an insulating body insertable between the contacts when released by a bimetal element

Abstract

A low voltage high-amp circuit breaker having a substantially rectangular bimetallic bistable element and a pair of terminals extending from the side thereof. The bistable element is attached to have one end move from a first normal electrically conductive position to a second non-electrically conductive position. The manual reset circuit breaker includes a manual reset lever and a non-conductive heat resistant extension blade connected to the reset lever via a rotatable shaft. The extension blade being positioned adjacent the moveable end of the bistable element and when the element is moved to its second position, the blade is moved to prevent the element from returning to its first conductive position until the circuit breaker is manually reset.

Claims

1. A high amperage circuit breaker comprising

a pair of spaced terminals being placed in series with the circuit to be protected;

a heat resistant electrical insulating plastic housing defining a body cavity, said body cavity having a base, a front wall, a rear wall and two side walls,

a cover to close said housing;

a rectangular thermally activated bistable mechanical element mounted in said cavity, at least one dimple formed on said bistable element;

a first contact being connected to one of said terminals, said first contact also connected to one end of said bistable element by means wherein the one end of said bistable element always remains stationary with respect to the first contact and in electrical contact with the first contact;

a second electrical contact attached to the other end of said bistable element;

said other end of said bistable element being free to move in a relatively vertical direction;

a third contact electrically connected to said other terminal and being positioned relative to said second contact wherein said second and third contact are normally in electrical contact with each other when the bistable element is in a first position, and said first position being to close the circuit of the circuit breaker;

said bistable element having a predetermined current response to quickly default when there is a predetermined over current, said deflection causing said other end of said bistable element to move from said first position to a second position and to cause said second contact to separate from said third contact by a predetermined distance to open the circuit of the circuit breaker, said circuit breaker being a manual-reset and further comprising

a plastic rotatable shaft having one end rotatably mounted in the said cavity base and the other end extending out of said housing for a predetermined distance,

said shaft other end extending out of said cover for a predetermined distance;

a pair of longitudinally spaced first and second integral bars extending from said rotatable shaft,

said second bar extending a predetermined distance from said first bar and being sized to provide predetermined electrical insulation, said second bar being in contact with the outer surface of said second contact when the electrical circuit is closed;

a spring attached to said first bar and said housing, said spring exerting a rotational force on said plastic shaft to urge the second bar in contact with and toward said second contact;

wherein when said second and third contacts are separated said spring rotates to position said second bar between said second and third contacts and electrically separates said second and third contacts from each other.

3. The circuit breaker of claim 1 wherein,

a blind hole is defined by said cavity adjacent said rear wall,

said rotatable shaft having said one end rotatably mounted in said blind hole

said first bar being adjacent the top of said housing,

said second bar being paddle shaped;

said dimples on said bistable element having a diameter of 5/16 to 3/8 inch and a central depth of 0.050 to 0.080 inches;

said first contact being connected to said one end of said bistable element by mechanical stake joint;

said second electrical contact attached to and extending from the underside of the other end of said bistable element; and

said bistable element having a length and width that is at least 75% of the length and width of said cavity.

5. The circuit breaker of claim 3 wherein the circuit breaker is a manual reset low voltage DC high-amp firewall mount circuit breaker wherein both terminals extend from a same side of the circuit breaker on the same side as said reset lever.

2. A high amperage circuit breaker comprising

a pair of spaced terminals being placed in series with the circuit to be protected;

a heat resistant electrical insulating plastic housing defining a body cavity, said body cavity having a base, a front wall, a rear wall and two side walls,

a cover to close said housing;

a rectangular thermally activated bistable mechanical element mounted in said cavity, at least one dimple formed on said bistable element;

a first contact being connected to one of said terminals, said first contact also connected to one end of said bistable element by means wherein the one end of said bistable element always remains stationary with respect to the first contact and in electrical contact with the first contact;

a second electrical contact attached to the other end of said bistable element;

said other end of said bistable element being free to move in a relatively vertical direction;

a third contact electrically connected to said other terminal and being positioned relative to said second contact wherein said second and third contact are normally in electrical contact with each other when the bistable element is in a first position, and said first position being to close the circuit of the circuit breaker;

said bistable element having a predetermined current response to quickly default when there is a predetermined over current, said deflection causing said other end of said bistable element to move from said first position to a second position and to cause said second contact to separate from said third contact by a predetermined distance to open the circuit of the circuit breaker, said bistable element further comprising at least two dimples formed on the upper face and adjacent opposite sides of said bistable element, and said bistable element having a length greater than a width with said length being greater than 1/2 the width, said circuit breaker being a manual-reset and further comprising

a plastic rotatable shaft having one end rotatably mounted in said cavity base and the other end extending out of said housing for a predetermined distance,

said other end of said shaft extending out of said cover for a predetermined distance;

a pair of longitudinally spaced first and second integral bars extending from said rotatable shaft,

said second bar extending a predetermined distance from said first bar and being sized to provide predetermined electrical insulation, said second bar being in contact with the outer surface of said second contact when the electrical circuit is closed;

a spring attached to said first bar and said housing, said spring exerting a rotational force on said plastic shaft to urge the second bar in contact with and toward said second contact;

wherein when said second and third contacts are separated said spring rotates to position said second bar between said second and third contacts and electrically separates said second and third contacts from each other.

4. The circuit breaker of claim 2 wherein the circuit breaker is a manual reset low voltage DC high-amp panel mount circuit breaker wherein both terminals extend from a same side of the circuit breaker opposite said reset lever side.

6. A high amperage manual reset D.C. circuit breaker comprising

a heat resistant electrical insulating plastic housing defining a rectangular central body cavity, with a base, front wall, a rear wall and two side walls;

a blind hole defined by said cavity base adjacent said rear wall;

a pair of spaced terminal bolts extending through said base with a pair of contact nuts being external of said housing, said spaced terminals being placed in series with the circuit to be protected;

an insulating plastic rotatable shaft having one end rotatably mounted in said blind hole and the other end extending out of said housing for a predetermined distance;

a cover to close said housing;

a seal placed between said housing and said cover to seal said cover to said housing;

means to permanently attach said cover to said housing;

said shaft other end extending out of said cover for a predetermined distance;

a seal ring attached to said cover and said shaft;

a pair of longitudinally spaced first and second integral bars extending from said rotatable shaft;

said first bar being adjacent the top of said housing;

a paddle shaped bar extending a predetermined distance from said first bar, said second bar having a relatively straight side, said second bar being sized to provide predetermined electrical insulation;

a generally rectangular thermally activated bistable mechanical element, a pair of dimples formed on an upper surface of and adjacent opposite sides of said bistable element, said dimples having a diameter of approximately 5/16 to 3/8 inch and a central depth of approximately 0.050 to 0.080 inches;

a first contact being connected to one of said terminals, said first contact also connected to end of said bistable element by a washer and a mechanical stake joint wherein the one end of said bistable element always remains stationary with respect to the first contact and in electrical contact with the first contact;

a second electrical contact attached to and extending from the underside of the other end of said second electrical contact;

said other end of said bistable element being free to move in a relatively vertical direction;

a vertical plane passing through a center of said first contact and a center of said second contact being perpendicular to a vertical plane passing through centers of said pair of dimples;

a third contact electrically connected to said other terminal and being positioned below said second contact, said second and third contact normally being in electrical contact with each other to close the circuit of the circuit breaker;

said second bar having its side in contact with the outer surface of said second contact when the electrical circuit is closed;

a spring attached to said first bar and said housing, said spring exerting a rotational force on said plastic shaft to urge the second bar in contact with said second contact and toward said second contact;

said bistable element having a predetermined current response to quickly deform when there is a predetermined over current, said deformation causes said other end to vertically rise and to cause said second contact to separate from said third contact by a predetermined distance; and

wherein said second and third contacts are separated said spring rotates to position said second bar between said second and third contacts and electrically separate said second and third contacts from each other.