Patent Application
20170278660
The field of the disclosure relates generally to circuit breakers and, more particularly, to circuit breakers including end covers.
Circuit breakers are often used to protect, in a residential, industrial, utility, or commercial environment, against overcurrent conditions, ground fault conditions, or other system anomalies that are undesirable and require the circuit breaker to interrupt the flow of current through the circuit breaker. At least some known circuit breakers include lugs for coupling to a circuit. For example, in some circuit breakers, a load lug is positioned on an end of the circuit breaker and a line lug is positioned on an opposite end of the circuit breaker. Current flows through the circuit breaker from the line lug to the load lug. When the circuit breaker has a reverse feed, the current flows through the circuit breaker from the load lug to the line lug. Sometimes, operation of the circuit breaker generates arc gases and particulates which cause deterioration of components of the circuit breaker. Accordingly, some circuit breakers include shielding to inhibit the arc gases and particulates from contacting components such as the line lugs.
At least some known circuit breakers include an electrically insulative case and end covers coupled to the ends of the electrically insulative case. Typically, a different end cover is required for coupling to each end of the electrically insulative case. For example, the end cover adjacent the line lugs is differentiated from the end cover adjacent the load lug to accommodate shielding that inhibits arc gas and particulates from contacting the line lugs. Moreover, each end cover is assembled from multiple unique parts which increase the number of parts required to assemble the circuit breakers. Also, some circuit breakers are assembled without lugs on at least one end. Accordingly, a different end cover, e.g., a finishing cover, is coupled to the electrically insulative case adjacent the end without lugs. As a result, the cost to manufacture and assemble circuit breakers including end covers is increased.
In one aspect, a circuit breaker is provided. The circuit breaker includes an electrically insulative case including a first end and a second end opposite the first end. The circuit breaker further includes an end cover selectively installable on both the first and second ends of the electrically insulative case. The end cover includes a wall defining at least one opening for receiving a removable shield, a first end connectable to the electrically insulative case first end, and a second end connectable to the electrically insulative case second end.
In another aspect, an end cover for a circuit breaker having an electrically insulative case is provided. The end cover is selectively installable on both a first end and a second end of the electrically insulative case. The end cover includes a first end and a second end opposite the first end. The first end of the end cover is connectable to the first end of the electrically insulative case and the second end of the end cover is connectable to the second end of the electrically insulative case. The end cover further includes a wall defining an interior space sized to receive at least one lug extending from the electrically insulative case.
In yet another aspect, a method of manufacturing a circuit breaker is provided. The method includes positioning a lug adjacent to an end of an electrically insulative case and coupling an end cover to the end of the electrically insulative case adjacent the lug. The end cover includes a wall defining at least one opening sized to receive at least one removable shield.
These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of the disclosure. These features are believed to be applicable in a wide variety of systems including one or more embodiments of the disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.
In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings.
The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “substantially,” and “approximately,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
Exemplary embodiments of circuit breakers and methods of manufacturing circuit breakers are described herein. The circuit breakers generally include an electrically insulative case and end covers coupled to line and load ends of the case. The end covers are interchangeable to reduce the number of unique parts required to manufacture and assemble circuit breakers. A removable shield couples to the end cover coupled to the line end to shield line lugs from arc gas and particulates during operation of the circuit breakers. A plug couples to the end cover coupled to the load end to close an opening for receiving the removable shield. In some embodiments, a finishing end cover is coupled to an end of the case when lugs are omitted from the respective end of the circuit breaker.
In reference to
In the exemplary embodiment, circuit breaker 100 further includes first end cover 124 and second end cover 126. First end cover 124 is coupled to first end 120 adjacent line lugs 112. Second end cover 126 is coupled to second end 122 adjacent load lugs 114. First end cover 124 and second end cover 126 receive line lugs 112 and load lugs 114 and are configured to electrically insulate line lugs 112 and load lugs 114 and to inhibit objects from contacting line lugs 112 and load lugs 114. Moreover, first end cover 124 and second end cover 126 protect line lugs 112 and load lugs 114 from the environment to inhibit deterioration of line lugs 112 and load lugs 114. First end cover 124 and second end cover 126 are interchangeable. In other words, first end cover 124 is configured to couple to second end 122 and second end cover 126 is configured to couple to first end 120. In alternative embodiments, first end cover 124 and second end cover 126 have any configurations that enable circuit breaker 100 to operate as described herein.
In the exemplary embodiment, removable shield 136 inhibits arc gas 140 and particulates from contacting line lugs 112 during operation of circuit breaker 100. As will be described below, removable shield 136 engages top wall 128. To install removable shield 136, removable shield 136 is inserted in opening 138 until a snap fit is achieved. When removable shield 136 is fully inserted in opening 138, a top surface 137 of removable shield 136 is substantially flush with a top surface 139 of top wall 128. In alternative embodiments, removable shield 136 is coupled to first end cover 124 in any manner that enables circuit breaker 100 to operate as described herein.
Also, in the exemplary embodiment, first end cover 124 further includes an upper portion 142 and a lower portion 144. Upper portion 142 includes top wall 128 and portions of side walls 132. Lower portion 144 includes bottom wall 130 and portions of side walls 132. Upper portion 142 and lower portion 144 are removably coupled together and at least partially define interior space 134. A plurality of partitions 150 extend between top wall 128 and bottom wall 130 and divide interior space 134 into a plurality of slots 152 for receiving line lugs 112. Each slot 152 corresponds with one opening 138 in top wall 128. Accordingly, removable shields 136 extend in slots 152 adjacent line lugs 112 when coupled to upper portion 142. In the illustrated embodiment, interior space is divided into three slots 152. In alternative embodiments, interior space 134 is divided into any slots 152 that enable circuit breaker 100 to operate as described herein.
In reference to
First engagement components 154 and second engagement components 156 each include a keyed projection having a shape that corresponds to a channel 157 on first end 120 or second end 122. To couple first end cover 124 to case 102, first engagement components 154 or second engagement components 156 are inserted at partially in the corresponding channels 157 on first end 120 or second end 122. Upper portion 142 is removably coupled to lower portion 144 to secure first engagement component 154 or second engagement component 156 in the corresponding channel. First engagement components 154 and second engagement components 156 are omitted on lower portion 144 such that lower portion 144 couples to case 102 in either direction. In alternative embodiments, first end cover 124 has any engagement components 154, 156 that enable circuit breaker 100 to operate as described herein. In some embodiments, at least one of first engagement component 154 and second engagement component 156 is adjustable to facilitate coupling first end cover 12 to different circuit breakers 100. For example, in some embodiments, first engagement components 154 include knockouts configured to facilitate coupling first end cover 124 to draw-out units.
In reference to
In the exemplary embodiment, plugs 172 are positioned in openings 138 such that a top surface 174 of each plug 172 is substantially flush with top surface 139 of second end cover 126. Each plug 172 includes engagement components 176 that engage top wall 128 when plug 172 is inserted in opening 138. Engagement components 176 include a plurality of ridges 178 and a lip 180. Ridges 178 deform as plug 172 is inserted through opening 138 and return to shape after passing through opening 138. As a result, engagement components 176 facilitate a snap-fit engagement between plug 172 and top wall 128 to inhibit displacement of plug 172 from opening 138. Lip 180 facilitates alignment of removable shield 136 in opening 138. In addition, lip 180 includes a tab 182 to facilitate removal of plug 172 from second end cover 126. To remove plug 172 from second end cover 126, a user applies force to a portion of plug 172, such as tab 182, until ridges 178 deform and allow release of plug 172 from opening 138. In some embodiments, plugs 172 are positioned in at least one opening 138 of first end cover 124. In alternative embodiments, circuit breaker 100 includes any plugs 172 that enable circuit breaker 100 to operate as described herein.
In reference to
The circuit breakers described above generally include an electrically insulative case and end covers coupled to line and load ends of the case. The end covers are interchangeable to reduce the number of unique parts required to manufacture and assemble circuit breakers. A removable shield couples to the end cover coupled to the line end to shield line lugs from arc gas and particulates during operation of the circuit breakers. A plug couples to the end cover coupled to the load end to close an opening for receiving the removable shield. In some embodiments, a finishing end cover is coupled to an end of the case when lugs are omitted from the respective end of the circuit breaker.
An exemplary technical effect of the methods, systems, and apparatus described herein includes at least one of: (a) reducing cost to assemble circuit breakers; (b) providing interchangeable end covers for circuit breakers; (c) reducing the number of unique parts required for circuit breakers; and (d) increasing the lifecycle of lugs.
Exemplary embodiments of circuit breakers and methods of manufacturing circuit breakers are described above in detail. The circuit breakers and methods are not limited to the specific embodiments described herein but, rather, components of the circuit breakers and/or operations of the methods may be utilized independently and separately from other components and/or operations described herein. Further, the described components and/or operations may also be defined in, or used in combination with, other systems, methods, and/or devices, and are not limited to practice with only the circuit beakers and systems described herein.
The order of execution or performance of the operations in the embodiments of the disclosure illustrated and described herein is not essential, unless otherwise specified. That is, the operations may be performed in any order, unless otherwise specified, and embodiments of the disclosure may include additional or fewer operations than those disclosed herein. For example, it is contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of aspects of the disclosure.
Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
