Narrow profile circuit breaker with arc interruption

Abstract

A circuit breaker design allows for the circuit breaker to have an overall width (i.e., measured along the circuit breaker's exposed outwardly-facing surface of its housing) that is narrower than achievable with known typical configurations, while at the same time still providing robust arc interruption capabilities. This is achieved in large part by providing a specific orientation of a moveable contact arm assembly and/or by providing a specific configuration of a current path within the housing.

Claims

1. A circuit breaker comprising: a housing within which components of the circuit breaker are disposed, the housing having an outwardly facing exposed surface; a line terminal adapted to be electrically connected to a source of electrical power; a load terminal adapted to be electrically connected to at least one load; a stationary contact positioned within the housing; a moveable contact arm assembly having a generally longitudinal axis and a moveable contact positioned thereon, the moveable contact arm assembly being moveable between a closed position in which the moveable contact and the stationary contact are in physical contact and the line terminal and the load terminal are in electrical communication via at least the moveable contact, the stationary contact and a conductive strap, and an open position in which the moveable contact and the stationary contact are out of physical contact and the line terminal and the load terminal are out of electrical communication; an overcurrent tripping device operably coupled to the moveable contact arm assembly via a linkage assembly and adapted to move the moveable contact arm assembly to the open position upon detection of an overcurrent situation; a resetting mechanism, actuation of which is adapted to, when the moveable contact arm assembly is in the open position, move the moveable contact arm assembly to the closed position, the resetting mechanism extending from, or being accessible through, the outwardly facing exposed surface of the housing; and an arc splitter adapted to quench an arc created between the stationary contact and the moveable contact as the stationary contact and the moveable contact are moveable into and/or out of contact with one another; wherein the outwardly facing exposed surface of the housing generally defines an exposed surface plane, and wherein the longitudinal axis of the moveable contact arm assembly is generally orthogonal with respect to the exposed surface plane when the moveable contact arm assembly is in the closed position; and wherein the conductive strap lies in a conductive strap plane, wherein the moveable contact arm assembly moves in a contact arm plane as it moves between the open and the closed position, and wherein the conductive strap plane and the contact arm plane are parallel to, but spaced apart from, one another.

2. The circuit breaker of claim 1 wherein the conductive strap plane and the contact arm plane are both generally orthogonal with respect to the exposed surface plane.

3. The circuit breaker of claim 1 wherein an imaginary plane exists that is parallel to the exposed surface plane and that passes through the moveable contact arm assembly and the conductive strap.

4. The circuit breaker of claim 3 wherein the imaginary plane also passes through the moveable contact and the stationary contact.

5. The circuit breaker of claim 1 wherein surfaces of the stationary contact and the moveable contact that physically contact each other both face in directions generally parallel to the exposed surface plane.

6. The circuit breaker of claim 1 wherein a width of the outwardly facing exposed surface taken parallel to the contact arm plane is less than 2 inches.

7. The circuit breaker of claim 6 wherein the width of the outwardly facing exposed surface taken parallel to the contact arm plane is less than 1.75 inches.

8. The circuit breaker of claim 7 wherein the width of the outwardly facing exposed surface taken parallel to the contact arm plane is less than 1.575 inches.

9. The circuit breaker of claim 1 wherein actuation of the resetting mechanism is further adapted to manually move the moveable contact arm assembly between the open position and the closed position.

10. The circuit breaker of claim 9, wherein the resetting mechanism comprises a handle having a portion thereof extending from the housing adapted to be actuated by a user.

11. The circuit breaker of claim 9, wherein the resetting mechanism comprises a rocker mechanism having a portion thereof extending from the housing adapted to be actuated by a user.

12. The circuit breaker of claim 1 wherein the arc splitter comprises a plurality of spaced apart conductive plates disposed within the housing.

13. The circuit breaker of claim 1 wherein the line terminal and the load terminal are disposed on a surface of the housing that is generally parallel to, and spaced apart from, the outwardly facing exposed surface.

14. A circuit breaker comprising: a housing within which components of the circuit breaker are disposed, the housing having an outwardly facing exposed surface; a line terminal adapted to be electrically connected to a source of electrical power; a load terminal adapted to be electrically connected to at least one load; a stationary contact positioned within the housing; a moveable contact arm assembly having a generally longitudinal axis and a moveable contact positioned thereon, the moveable contact arm assembly being moveable between a closed position in which the moveable contact and the stationary contact are in physical contact and the line terminal and the load terminal are in electrical communication, and an open position in which the moveable contact and the stationary contact are out of physical contact and the line terminal and the load terminal are out of electrical communication; an overcurrent tripping device operably coupled to the moveable contact arm assembly via a linkage assembly and adapted to move the moveable contact arm assembly to the open position upon detection of an overcurrent situation; a resetting mechanism, actuation of which is adapted to, when the moveable contact arm assembly is in the open position, move the moveable contact arm assembly to the closed position, the resetting mechanism extending from, or being accessible through, the outwardly facing exposed surface of the housing; and an arc splitter adapted to quench an arc created between the stationary contact and the moveable contact as the stationary contact and the moveable contact are moveable into and/or out of contact with one another; wherein the outwardly facing exposed surface of the housing generally defines an exposed surface plane, and wherein the longitudinal axis of the moveable contact arm assembly is generally orthogonal with respect to the exposed surface plane when the moveable contact arm assembly is in the closed position; and wherein surfaces of the stationary contact and the moveable contact that physically contact each other both face in directions generally parallel to the exposed surface plane.

15. The circuit breaker of claim 14 wherein: when the moveable contact arm assembly is in the closed position and the moveable contact and the stationary contact are in physical contact, the line terminal and the load terminal are in electrical communication via at least the moveable contact, the stationary contact and a conductive strap; and wherein the conductive strap lies in a conductive strap plane, wherein the moveable contact arm assembly moves in a contact arm plane as it moves between the open and the closed position, and wherein the conductive strap plane and the contact arm plane are parallel to, but spaced apart from, one another.

16. The circuit breaker of claim 15 wherein the conductive strap plane and the contact arm plane are both generally orthogonal with respect to the exposed surface plane.

17. The circuit breaker of claim 16 wherein an imaginary plane exists that is parallel to the exposed surface plane and that passes through the moveable contact arm assembly and the conductive strap.

18. The circuit breaker of claim 17 wherein the imaginary plane also passes through the moveable contact and the stationary contact.

19. A circuit breaker comprising: a housing within which components of the circuit breaker are disposed, the housing having an outwardly facing exposed surface; a line terminal adapted to be electrically connected to a source of electrical power; a load terminal adapted to be electrically connected to at least one load; a stationary contact positioned within the housing; a moveable contact arm assembly having a moveable contact positioned thereon, the moveable contact arm assembly being moveable between a closed position in which the moveable contact and the stationary contact are in physical contact and the line terminal and the load terminal are in electrical communication via at least the moveable contact, the stationary contact and a conductive strap, and an open position in which the moveable contact and the stationary contact are out of physical contact and the line terminal and the load terminal are out of electrical communication; an overcurrent tripping device operably coupled to the moveable contact arm assembly via a linkage assembly and adapted to move the moveable contact arm assembly to the open position upon detection of an overcurrent situation; a resetting mechanism, actuation of which is adapted to, when the moveable contact arm assembly is in the open position, move the moveable contact arm assembly to the closed position, the resetting mechanism extending from, or being accessible through, the outwardly facing exposed surface of the housing; and an arc splitter adapted to quench an arc created between the stationary contact and the moveable contact as the stationary contact and the moveable contact are moveable into and/or out of contact with one another; wherein the conductive strap lies in a conductive strap plane, wherein the moveable contact arm assembly moves in a contact arm plane as it moves between the open and the closed position, and wherein the conductive strap plane and the contact arm plane are parallel to, but spaced apart from, one another; wherein the outwardly facing exposed surface of the housing generally defines an exposed surface plane; wherein the conductive strap plane and the contact arm plane are both generally orthogonal with respect to the exposed surface plane; and wherein an imaginary plane exists that is parallel to the exposed surface plane and that passes through the moveable contact arm assembly and the conductive strap.

20. The circuit breaker of claim 19 wherein the imaginary plane also passes through the moveable contact and the stationary contact.

21. The circuit breaker of claim 20 wherein surfaces of the stationary contact and the moveable contact that physically contact each other both face in directions generally parallel to the exposed surface plane.

22. The circuit breaker of claim 19 wherein the moveable contact arm assembly has a generally longitudinal axis that is generally orthogonal with respect to the exposed surface plane when the moveable contact arm assembly is in the closed position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a side elevational view, partially broken away, illustrating an exemplary circuit breaker constructed in accordance with the present invention.

(2) FIG. 2 is a top plan view illustrating a portion of the exemplary circuit breaker constructed in accordance with the present invention as shown in FIG. 1.

(3) FIG. 3 is a side elevational view, partially broken away, illustrating a portion of the exemplary circuit breaker constructed in accordance with the present invention as shown in FIG. 1, but where the rocker-type actuator has been replaced with a handle-type actuator.

(4) FIG. 4 is a side elevational view, partially broken away, illustrating another exemplary circuit breaker constructed in accordance with the present invention.

(5) FIG. 5 is a top plan view illustrating a portion of the exemplary circuit breaker constructed in accordance with the present invention as shown in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

(6) Referring now to the drawings, wherein like reference numerals designate corresponding structure throughout the views.

(7) FIG. 1 illustrates components of an example circuit breaker (100) having an improved design that allows for the circuit breaker (100) to have an overall width (i.e., measured along the circuit breaker's exposed outwardly facing surface) that is narrower than permitted with known typical configurations, while at the same time still providing robust arc interruption capabilities.

(8) Circuit breaker (100) is provided with a housing (102) that contains the working elements of the device. The circuit breaker (100) is further provided with a set of contacts including a stationary contact (104) and movable contact (106). The moveable contact (106) is positioned on a moveable contact arm assembly (108), and the moveable contact (106) is configured to move between an open and closed position relative to the stationary contact (104). FIG. 1 shows the contacts (104, 106) in the closed position where electrical current flows therebetween, whereas FIG. 4 shows the contacts (104, 106) both in the closed position (represented by solid lines) where electrical current flows therebetween and an open position (represented by dashed lines) where no electrical current flows therebetween.

(9) Also shown in FIG. 1 is a line terminal (110), which is designed to be connected to a source of electrical power (not shown), such as a bus bar in a panel board or load center. Stationary contact (104) is mounted onto a first conductive element (112), which in turn is electrically connected to line terminal (110).

(10) Also provided is a load terminal (116), which is designed to be connected to the electrical components (not shown) being fed from the circuit breaker, such as an individual component connected directly to a circuit breaker (e.g., an air conditioner unit), or multiple components through a power wire which terminates at electrical outlets.

(11) Moveable contact (106) mounted on moveable contact arm assembly (108) is in indirect electrical communication with the load terminal (116). More specifically, the moveable contact arm assembly (108), which is electrically conductive, is in electrical communication with an input side of an overcurrent tripping device (114) through a conductive connector (115). An output side of the overcurrent tripping device (114) is in electrical communication with a conductive strap (118) through a conductive connector (117), with the conductive strap (118) being in electrical communication, via another conductive connector (120) with a second conductive element (119), on which the load terminal (116) is mounted.

(12) In operation, and when the circuit breaker is in the on state (i.e., when the stationary contact (104) and the moveable contact (106) are closed and thereby in electrical communication), electrical power is input into circuit breaker (100) via line terminal (110) and exits the circuit breaker (100) vis the load terminal (116). The flow of electricity through the circuit breaker (indicated by arrows in FIG. 1) will now be discussed.

(13) As indicated, electrical power flows into the circuit breaker (100) through line terminal (110), and then passes through first conductive element (112) to stationary contact (104). The contacts being closed, the electrical power flows through moveable contact (106), through conductive contact arm assembly (108), through conductive connector (115) and to the input side of an overcurrent tripping device (114). The electrical power then flows out the output side of the overcurrent tripping device (114) through conductive connector (117), through conductive strap (118) and then through conductive connector (120) and conductive element (119), exiting the circuit breaker through load terminal (116).

(14) If the electrical current exceeds a threshold level, overcurrent tripping device (114) will function to trip the circuit breaker (100) by opening the circuit (opening the contacts relative to each other by means of a trip mechanism (121) and linkage assembly (122) such that the flow of electrical current through the contacts (104,106) ceases. In the event that the electrical current does not exceed the threshold level set by overcurrent tripping device (114), the electrical power is allowed to pass through load terminal (116), which in turn, provides electrical power to the connected circuit and/or equipment.

(15) The circuit breaker (100) also includes a resetting mechanism (124) adapted to reset the circuit breaker (100) and move the moveable contact (106) into physical contact with the stationary contact (104) by movement of the moveable contact arm assembly (108). The resetting mechanism (124) is connected to the linkage assembly (122), which in turn, is connected to the moveable contact arm assembly (108) for this purpose. The resetting mechanism (124) may also be used to manually open and close the contacts (104,106), i.e., to turn the circuit breaker (100) on and off, as is known in the art.

(16) In the exemplary embodiment shown in FIG. 1 the resetting mechanism (124) takes the form of a low profile rocker-type actuator, and the linkage assembly (122) is particularly adapted to work in conjunction with this type of low profile rocker-type actuator resetting mechanism (124). The particular configuration of this type of resetting mechanism (124) and linkage assembly (122) forms a large part of the subject matter to which is directed U.S. Pat. No. 9,947,499, which is assigned to the assignee of the present application. As such, a detailed description thereof is not repeated herein. Instead, the entire contents of U.S. Pat. No. 9,947,499 are hereby incorporated herein in their entirety.

(17) It should be noted, however, that the resetting mechanism and/or the linkage assembly may take other forms. For example, referring now to FIG. 3, the resetting mechanism (124) of the shown exemplary circuit breaker (100) takes the form of a traditional handle-type actuator, and the linkage assembly (122) is particularly adapted to work in conjunction with this type of handle-type actuator resetting mechanism (124). As such handle-type resetting mechanisms (124) and corresponding linkage assemblies (122) are well known in the art, further details thereof are not provided herein.

(18) Referring again specifically to FIG. 1, the circuit breaker (100) is shown in the on position, where the contacts (104,106) are closed. As is known, when the circuit breaker (100) is manually turned off or when an overcurrent situation is sensed, the contacts (104,106) are caused to open, to thereby cease the flow of electrical power through the circuit breaker (100). However, also as is known, although moveable contact (106) has separated from stationary contact (104), electricity, in the form of an arc (not shown) may still flow from electrical contact (104) to electrical contact (106). The arc may be capable of jumping between electrical contacts, through air, and can cause severe damage to both contacts (104,106). In a worst case scenario, a single arc can damage the contacts so severely as to render them inoperable during normal operation. To protect electrical contacts (104,106), and circuit breaker (100) overall, any created arc must be extinguished as quickly as possible. This is done by pushing the arc into an arc splitter disposed within an arc chamber (128).

(19) The arc splitter may take the form of a plurality of spaced apart, generally metallic, plates (130) which draw the arc in, and cool and quench the arc. Each plate (130) may be spaced apart at the same distance, or the distance between each plate (130) may vary depending on the application of circuit breaker. For example, each plate (130) may be spaced apart approximately 0.8 inches from the next plate, or the distance between each plate (130) may be varied. For example, the plates toward one side of the housing may be closer together than the plates towards the other side of the housing, or vice versa.

(20) Additionally, one or more arc straps (132,134) may be provided in order to provide a safe place for the arc to jump prior to the arc being fully extinguished. In the shown example, a first arc strap (132) is in electrical communication with the line terminal (110), while a second arc strap (134) is in electrical communication with the load terminal (116).

(21) The housing (102) of the circuit breaker (100) includes an outwardly facing exposed surface (126) through which the resetting mechanism (124) extends and/or is accessible by a user. As will be understood by those skilled in the art, circuit breakers of the type discussed herein are configured to be inserted into panels with a plurality of other circuit breaker (at least some of which are typically identical to others). A typical home, for example, has at least one, and perhaps two, three or even more, such panels, each of which may include 10, 20 or even more circuit breakers. Also as is understood by those skilled in the art, generally only one surface of each of the circuit breakers (i.e., the one carrying the resetting mechanism) is exposed. This outwardly facing exposed surface (shown as 126 in FIG. 1) generally defines a plane (shown as A in FIG. 1). Typically, all of the circuit breakers disposed in each panel their outwardly facing exposed surface lying in the same plane (A).

(22) As discussed, one of the objects of the present invention is to provide a circuit breaker design having a width (B), which is narrower than is typically achievable in circuit breakers of the type disclosed. By width (B), what is meant is the dimension of the outwardly facing exposed surface (126) taken parallel to a plane in which the moveable contact arm assembly (108) moves as it opens and closes. This is as opposed to the height (C) of the circuit breaker (shown in FIG. 2), which corresponds to the dimension of the outwardly facing exposed surface (126) taken perpendicular to a plane in which the moveable contact arm assembly (108) moves as it opens and closes. While the height (C) may be of particular concern in the context of some circuit breakers, it is the width (B) of the circuit breaker (100) that is of particular concern here.

(23) Incidentally, the reason that the terms width and height are used herein is because the circuit breakers are typically disposed in panels such that the line terminal (110) and the load terminal (116) are disposed generally horizontally, with multiple circuit breakers being stacked one on top of another such that the line terminals (110) of the stacked circuit breakers are generally vertically aligned and the load terminals (116) of the stacked circuit breakers are generally vertically aligned. With respect to the embodiment shown in FIG. 3, this would mean that the handle-type actuator resetting mechanism (124) would be moveable horizontally left-to-right and right-to-left when facing the panel of circuit breakers. Typically, a panel for residential use includes two stacks of circuit breakers.

(24) Preferably, the width (B) of the outwardly facing exposed surface (126) is less than 2 inches, and more preferably less than 1.75 inches. As but an illustrative example, the width (B) of the outwardly facing exposed surface (126) of circuit breaker (100) may be about 1.570 inches, while the height (C) (shown in FIG. 2), may be about 0.75 inches. In this embodiment, the depth of the circuit breaker (100)i.e., the dimension between the outwardly facing exposed surface (126) and the terminals (110,116)may be about 3.0 inches. It should be noted that while this depth may be greater than typical circuit breakers (and is certainly greater than low profile circuit breakers particularly configured to reduce depth), the circuit breaker (100) of the present invention is particularly concerned with providing reduced width (B), not necessarily depth.

(25) Ways in which the reduced width (B) of circuit breaker (100) can be achieved in accordance with the present invention will now be discussed.

(26) Again referring to FIG. 1, it will be noted that when the circuit breaker (100) is in the on position, such that the contacts (104,106) are closed, a longitudinal axis (D) of the moveable contact arm assembly (108) is generally orthogonal with respect to the plane (A) defined by the outwardly facing exposed surface (126). Stated another way, the faces of the contacts (104,106) that make contact with each other both face in directions generally parallel to the plane (A) defined by the outwardly facing exposed surface (126).

(27) This is in contrast with typical circuit breaker designs where the moveable contact arm assembly is generally parallel with respect to the plane defined by the outwardly facing exposed surface (i.e., where the faces of the contacts that make contact with each other both face in directions generally orthogonal to the plane defined by the outwardly facing exposed surface), as can be seen, for example, in U.S. Pat. No. 9,947,499, or where the moveable contact arm assembly is disposed at an acute or obtuse angle with respect to the plane defined by the outwardly facing exposed surface (i.e., where the faces of the contacts that make contact with each other both face in directions generally defining acute or obtuse angles with respect to the plane defined by the outwardly facing exposed surface), as may be the case with other low profile circuit breaker designs.

(28) Still referring to FIG. 1, the particular configuration of the conductive strap (118), and particularly its relationship with the moveable contact arm assembly (108) and contacts (104,106) is also important in connection with allowing for the reduced width (B) of circuit breaker (100) to be achieved.

(29) More specifically, as can be clearly seen with respect to the orientation illustrated in FIG. 1, the conductive strap (118) passes behind, and if offset from, the moveable contact arm assembly (108) and contacts (104,106). More generally speaking, the conductive strap (118) can be considered to lie in a plane, while the moveable contact arm assembly (108) can be considered to open/close in a different plane, with these two planes being parallel to, but spaced apart from one another by a distance. It should further be noted that both of these planes are generally orthogonal with respect to the plane (A) defined by the outwardly facing exposed surface (126).

(30) In the specific example shown in FIG. 1, it can further be the that an imaginary plane exists that is parallel to the plane (A) defined by the outwardly facing exposed surface (126), and that passes through all four of the conductive strap (118), the moveable contact arm assembly (108), the moveable contact (106) and the stationary contact (104).

(31) However, this particular relationship need not be true in all embodiments. For example, referring to the circuit breaker (100) embodiment shown in FIGS. 4 and 5, in this embodiment, it can indeed be the that the conductive strap (118) can be considered to lie in a plane, while the moveable contact arm assembly (108) can be considered to open/close in a different plane, with these two planes being parallel to, but spaced apart from one another by a distance. It can indeed further be the that both of these planes are generally orthogonal with respect to the plane (A) defined by the outwardly facing exposed surface (126). However, in this particular embodiment there is no imaginary plane that is parallel to the plane (A) defined by the outwardly facing exposed surface (126), and that passes through all four of the conductive strap (118), the moveable contact arm assembly (108), the moveable contact (106) and the stationary contact (104). Although, there is, even in this embodiment, an imaginary plane that is parallel to the plane (A) defined by the outwardly facing exposed surface (126), and that passes through both of the conductive strap (118) and the moveable contact arm assembly (108).

(32) In other respects, the embodiment of FIGS. 4 and 5 is similar to those previously discussed, though various minor differences will be noted in various components, such as housing (102), first conductive element (112), conductive element (119), arc chamber (128), arc plates (130), and arc straps (132,134). While these differences do not materially affect operation of the circuit breaker (100), they may result in slightly different dimensions, with circuit breaker (100), for example, having a width (B) of about 1.575 inches, a height (C) of about 0.75 inches and a depth (i.e., the dimension between the outwardly facing exposed surface (126) and the terminals (110,116)) of about 2.625 inches.

(33) Although the invention has been described with reference to a particular arrangement of parts, features and the like, these are not intended to exhaust all possible arrangements or features, and indeed many other modifications and variations will be ascertainable to those of skill in the art.