Patent Application
20160049263
The present invention relates to circuit breakers.
Circuit breakers are one of a variety of overcurrent protection devices used for circuit protection and isolation. The circuit breaker provides electrical protection whenever an electric abnormality occurs. In a typical circuit breaker, current enters the system from a power line and passes through a line conductor to a stationary contact fixed on the line conductor, then to a movable contact. The movable contact is fixedly attached to a pivoting arm. As long as the stationary and movable contacts are in physical contact, current passes from the stationary contact to the movable contact and out of the circuit breaker to down-stream electrical devices.
In the event of an overcurrent condition (e.g., a short circuit), extremely high electromagnetic forces can be generated. The electromagnetic forces repel the movable contact away from the stationary contact. Because the movable contact is fixedly attached to the rotating arm, the arm pivots and physically separates the stationary and movable contacts, thus tripping the circuit. Upon separation of the contacts and blowing open the circuit, an arcing condition occurs. The breaker's trip unit will trip the breaker which will cause the contacts to separate.
In the past, as shown in
Embodiments of the present invention are directed to circuit breakers with new and inventive handle bearing configurations.
Embodiments of the invention are directed to circuit breakers. The circuit breakers include a housing, a pivotable handle held by the housing, and an arm held in the housing in communication with the handle. The circuit breaker includes at least one pin held by the handle such that a longitudinal axis of the at least one pin is parallel to and offset from a pivot axis of the pivotable handle and a moveable contact arm comprising a first end portion engaging the at least one pin and configured to move responsive to a force applied to the first end portion of the arm by the pivotable handle through the at least one pin.
The first end portion can be held in an arm receiving channel in the handle and an opposing second end portion can have an electrical movable contact. The circuit breaker can also has a stationary electrical contact held in the housing and at least one pin held by the pivotable handle and residing in the housing so that the first end portion of the arm moves against the at least one pin as the arm and handle move between ON and OFF positions in the housing.
The circuit breaker can also have a TRIP operative position. The first end portion of the arm can move against the at least one pin as the arm and handle move between the ON and OFF positions and the TRIP position.
The at least one pin can provide the only contact between the arm and the handle.
The at least one pin can be a single pin, and the first end portion of the arm can move back and forth under the pin while in continuous abutting contact with the pin.
The at least one pin can be a single pin. The pivotable handle can have a pivot attachment with an axially extending centerline (pivot axis). The pin can have an axially extending centerline. The pin centerline can be offset from the pivot axis (attachment centerline of the handle).
The pin centerline can be below and laterally offset from the pivot axis of the handle.
The first end portion of the arm can have a curvilinear pin channel that slidably holds the at least one pin.
The at least one pin can be a single pin. The first end portion of the arm can have an arcuate pin channel that holds the pin.
The pin can be non-rotatably mounted to the handle.
The at least one pin can be metallic.
The upper end portion of the arm has a width and wherein the arm receiving channel of the handle can have a width that is about the same as the arm width (e.g., a bit oversize such as 0.01 inches to about 0.1 inches to receive the arm but not allow substantial side to side movement to provide alignment with other cooperating components).
The pin can have a length that is between about 0.115 inches and about 0.328 inches, in some embodiments.
The at least one pin can be a single pin that is held in a pin aperture in the handle to span across the arm receiving channel.
The pin aperture can have a first shoulder on one side of the arm receiving channel and a blind channel residing across from the shoulder on an opposing side of the arm receiving channel. The pin extends through the shoulder, across the arm receiving channel and into the blind channel.
The circuit breaker can be configured so the arm has an elongate concave shape with the upper end portion having a tip end. The arm receiving channel can extend across an entire bottom portion of the handle and can have a tip end that allows the tip end of the arm to retract and extend therefrom. The pin can be held closer to the tip end of the arm receiving channel.
Other embodiments are directed to handle bearing assemblies for a circuit breaker.
The assemblies can include a pivotable handle for a circuit breaker configured to rotate between ON and OFF positions, the handle having an inner portion comprising an arm receiving channel and at least one pin extending across the arm receiving channel, the at least one pin configured to cooperate with an arm providing a movable contact for the circuit breaker.
The arm receiving channel can extend across an entire bottom portion of the handle and have a tip end that allows a tip end of an arm to slidably retract and extend therefrom. The at least one pin can be held closer to the tip end of the arm receiving channel. The at least one pin can provide the only contact between the arm and the handle.
The at least one pin can be a single pin. The pivotable handle can have a pivot attachment joint with an axially extending centerline (pivot axis). The pin can have an axially extending centerline and the pin centerline can be offset from the pivot axis of the handle.
The pin centerline can be laterally and longitudinally offset from the pivot axis of the handle.
The at least one pin can be a single pin. The first end portion of the arm can have an arcuate pin channel that holds the pin and the pin can be non-rotatably mounted to the handle.
The at least one pin can be a single pin that is held in a pin aperture in the handle to span across the arm receiving channel. The pin aperture can extend through a first shoulder on one side of the arm receiving channel and a blind channel residing across from the shoulder on an opposing side of the arm receiving channel. The pin can extend through the shoulder, across the arm receiving channel and into the blind channel.
The handle bearing configurations can be configured to withstand the UL 489 (standard BR2125) endurance test requirements, e.g., 10,000 repetitions of handle movement through the operative positions, without failure and/or undue degradation.
Further features, advantages and details of the present invention will be appreciated by those of ordinary skill in the art from a reading of the figures and the detailed description of the preferred embodiments that follow, such description being merely illustrative of the present invention.
It is noted that aspects of the invention described with respect to one embodiment, may be incorporated in a different embodiment although not specifically described relative thereto. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination. Applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to be able to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner. These and other objects and/or aspects of the present invention are explained in detail in the specification set forth below.
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. Like numbers refer to like elements and different embodiments of like elements can be designated using a different number of superscript indicator apostrophes (e.g., 40, 40′, 40″, 40′″).
In the drawings, the relative sizes of regions or features may be exaggerated for clarity. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
Spatially relative terms, such as “beneath”, “below”, “bottom”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass orientations of above, below and behind. The device may be otherwise oriented (rotated 90° or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The term “about” refers to numbers in a range of +/−20% of the noted value.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes,” “comprises,” “including” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
The term “non-ferromagnetic” means that the noted component is substantially free of ferromagnetic materials so as to be suitable for use in the arc chamber (non-disruptive to the magnetic circuit) as will be known to those of skill in the art.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The term “self-retaining” with respect to a handle bearing pin means that the pin engages a handle to lock into an axial and non-rotatable position and requires no other retention component.
The handle can be associated with a disconnect operator (e.g., an operating handle) connected to an assembly for opening and closing separable main contacts in a circuit breaker or for turning power ON and OFF using a switch associated with a fuse. The circuit breaker can be for a motor starter unit or feeder unit, for example.
Turning now to the figures,
The pin 18 can be held by and/or in the handle 15 so that a longitudinal axis of the pin 18 is parallel to and offset from a pivot axis of the pivotable handle 15, which can provide a suitable torque lever arm.
It is noted that not all circuit breakers 10 require a TRIP position (e.g., fused switches), so in some embodiments, the arm 25 and handle 15 can include only two operative positions, ON, OFF, rather than the noted ON, OFF and TRIP positions.
As is well known, in the housing 10h, the circuit breaker 10 includes at least one arc chamber 20 having at least one arc chute 30 with arc plates 31 (
As shown in
The handle 15 can have an internal portion 15i with an arm receiving channel 17 that remains inside the housing 10h (
The pin 18 can provide the only direct moving contact between the handle 15 and arm 25.
Still referring to
Referring again to
A respective circuit breaker 10 can have a plurality of respective pairs of handles 15 and arms 25 as is also well known in the art.
As discussed above, the handle 15 can have an internal portion 15i with channel 17 (
The handle 15 with the pin 18 can be provided as a handle bearing assembly/subassembly.
With the circuit breaker oriented with the handle 15 extending upward as shown, the arm 25 can be configured to have an elongate concave shape with the upper end portion 25e having a tip end 25t. The arm receiving channel 17 can extend across an entire bottom portion of the handle 15l and can have an open tip end 17t (
The circuit breaker 10 can be configured to provide a stop 10s proximate the window 10w and extending inwardly to contact a handle ledge 19 that extends above the arm channel 17 when the handle 15 is in the ON position (
The handle arm channel 17 can have sidewalls 17w on both sides, one of which can be longer than the other, 17wl. The longer channel 17wl can extend down a distance that is between about 1.5× to about 10 times the length of the shorter sidewall, typically between about 2× to about 5×, such as about 3×.
The arm receiving channel 17 can extend across an entire diameter of a bottom portion of the handle as shown in
As shown in
In some embodiments, the line L can be drawn through the axially extending centerline of the pin 18, 18′, 18″ and the center of the pivot axis 15p with the angles of the line L being a as described above for the pin slot 16s in FIGS. 8A/8B, whether the pin slot configuration is used or not. Thus, in some embodiments, the line L can be offset from vertical by the angle α that is typically between about 10-60 degrees, more typically between about 10-30 degrees, such as about 10 degrees, about 11 degrees, about 12 degrees, about 13 degrees, about 14 degrees, about 15 degrees, about 16 degrees, about 17 degrees, about 17.5 degrees, about 18 degrees, about 19 degrees, about 20 degrees, about 21 degrees, about 22 degrees, about 23 degrees, about 24 degrees, about 25 degrees and about 30 degrees.
The pin 18, 18′, 18″ can be configured as a free floating or loose pin and is not required to be non-rotatable, in some embodiments.
Combinations of the pin configurations or other surface features may also be used, alone or with adhesives or other securing or locking configurations.
The at least one pin 18, 18′, 18″ may be electrically conductive or electrically non-conductive. The at least one pin 18, 18′, 18″ may comprise a metallic material or other suitable wear-resistant, sufficiently durable material. The at least one pin 18, 18′, 18″ may comprise a ceramic or fiber and/or glass reinforced resin. The at least one pin 18, 18′, 18″ may comprise a sufficiently rigid polymeric material. The at least one pin 18, 18′, 18″ may be a monolithic unitary member or comprise matable members or more than one material or a primary substrate with a coating, for example. The at least one pin 18, 18′, 18″ can be non-ferromagnetic.
The pin 18, 18′, 18″ can have a length L that is between about 0.115 inches and about 0.328 inches, in some embodiments. The channel 17 can have a width W that is greater than the length of the pin 18, 18′, 18″, typically between about 1.1× to about 1.25×, a width W that is about the same length of the pin 18, 18′, 18″ or a width W that is less than a length of the pin 18, 18′, 18″. If the pin 18, 18′, 18″ has a length that is less than a width of the channel 17, the length L is sufficient to extend across the channel 17 to engage a sidewall 17w on each side.
The pin 18, 18′ may be held by the handle 15 in other configurations, e.g., without requiring or outside of a channel 17.
The handle 15 can be a monolithic molded polymeric member. The at least one pin 18, 18′, 18″, typically a single pin, can be any suitable material and can be selected to provide the durability and performance criteria associated with UL 489 endurance testing. The pin 18, 18′, 18″ can be attached to the handle 15 in any suitable manner. The pin 18, 18′, 18″ can be inserted into a pre-formed pin aperture 16. The pin 18, 18′, 18″ may be overmolded into the handle 15 without requiring a pre-formed pin aperture 16. The pin 18, 18′, 18″ may be ultrasonically welded and/or inserted into the handle 15. The pin 18, 18′, 18″ may be punched, pressed or otherwise physically inserted into the aperture 16.
In some embodiments, the circuit breakers 10 can be DC circuit breakers, AC circuit breakers, or both AC and DC circuit breakers.
The circuit breakers 10 can be rated for voltages between about 1 V to about 5000 volts (V) DC and/or may have current ratings from about 15 to about 2,500 Amperes (A). The circuit breakers 10 may be high-rated miniature circuit breakers, e.g., above about 70 A in a compact package. However, it is contemplated that the circuit breakers 10 and components thereof can be used for any voltage, current ranges and are not limited to any particular application as the circuit breakers can be used for a broad range of different uses.
The circuit breakers 10 can be a bi-directional direct current (DC) molded case circuit breaker (MCCB). See, e.g., U.S. Pat. Nos. 5,131,504 and 8,222,983, the contents of which are hereby incorporated by reference as if recited in full herein. The DC MCCBs can be suitable for many uses such as data center, photovoltaic, and electric vehicles applications.
As is known to those of skill in the art, Eaton Corporation has introduced a line of molded case circuit breakers (MCCBs) designed for commercial and utility scale photovoltaic (PV) systems. Used in solar combiner and inverter applications, Eaton PVGard™ circuit breakers are rated up to 600 amp at 1000 Vdc and can meet or exceed industry standards such as UL 489B, which requires rigorous testing to verify circuit protection that meets the specific requirements of PV systems. However, it is contemplated that the circuit breakers 10 can be used for various applications with corresponding voltage capacity/rating. In some particular embodiments, the circuit breaker 10 can be a high-rating miniature circuit breaker.
The circuit breaker 10 may be particularly suitable for the BR circuit breakers with a thermal-magnetic trip curve that avoids nuisance tripping on mild overloads while reacting almost instantaneously to severe short-circuit conditions, such as the BRX circuit breaker from Eaton Corporation, Cleveland, Ohio.
The handle bearing configuration provided by the pin 18, 18′, 18″ can remove a plastic wear point of the prior art configuration and reduce wear, eliminate or reduce wear and heat (friction induced) relative to the design shown in
The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the invention.
