Patent Publication Number: US-2022239075-A1

Title: Apparatus and method for drill motor racking of switchgear

Description:
PRIOR RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/142,372 entitled “Apparatus and Method for Drill Motor Racking of Switchgear,” filed on Jan. 27, 2021, which is incorporated by reference herein in its entirety. 
    
    
     FEDERALLY SPONSORED RESEARCH STATEMENT 
     Not Applicable (N/A) 
     REFERENCE TO MICROFICHE APPENDIX 
     N/A 
     FIELD OF INVENTION 
     The disclosure is related to the operation of a circuit breaker that have a racking screw or a racking shaft to facilitate removal of the breaker from its cubicle, and in particular, to a portable device that facilitates the remote racking of such circuit breaker. 
     BACKGROUND OF THE INVENTION 
     In larger circuit breaker systems, a typical circuit breaker may be disconnected from the buss and removed from its cubicle by a method described in the industry as “racking” the breaker. This may be accomplished by an operator who uses a temporary hand crank to physically rotate a racking screw located on the face of the circuit breaker. 
     In order to effect the operation described above, the operator must stand within arms-reach of the circuit breaker, which also means the operator is in close proximity to the circuit breaker. If the circuit breaker should happen to fail catastrophically, the operator is at risk of serious injury or death from the resulting arc-blast and flying debris. 
     Recognizing the potential hazard of personal injury associated with the local racking operation of an electrical circuit breaker, there is a need for a portable, easy-to-use apparatus that provides a means for remotely racking the circuit breaker from a safe distance. 
     The apparatus should be easy to use, relatively low weight and cost effective. 
     SUMMARY OF THE INVENTION 
     An object of the disclosure is to provide a portable apparatus that facilitates the remote racking of a circuit breaker by means of utilizing a commercially available drill motor. Another object of the disclosure is to provide a portable apparatus that is operated from a distance that allows an operator to be positioned a safe distance away from the circuit breaker that is being operated. Yet another object of this disclosure is to provide a portable actuating apparatus that is temporarily affixed to the circuit breaker, in order to facilitate portable use of the invention, without the need of permanently modifying or altering the circuit breaker or its racking system. Yet another object of this disclosure is to provide a means of remotely racking a circuit breaker without external power except for that mechanical rotational power provided by the commercially available drill motor. 
     In an embodiment, a drill motor racking apparatus for remote operation of a circuit breaker comprises a racking adapter, a gearbox, a flexible shaft cable, and a drill adapter. 
     In an embodiment, the racking adapter is adapted to be engaged by and secured in a racking mechanism of the circuit breaker. In an embodiment, the racking adapter comprises a socket. In an embodiment, the racking adapter comprises a shaft. 
     In an embodiment, the racking adapter is adapted to be secured to the racking mechanism of the circuit breaker by an engagement means. 
     In an embodiment, the engagement means is one or more of a bracket, a friction fit, a latch, and a magnet. In an embodiment, the engagement means is a friction fit. 
     In an embodiment, the gearbox has an input and an output. In an embodiment, the gearbox is incorporated between the flexible shaft cable and the racking adapter to provide a torque multiplication required to rack the circuit breaker. 
     In an embodiment, the flexible shaft cable has a first end and a second end. In an embodiment, the racking adapter is connected to the first end of the flexible shaft cable. In an embodiment, the flexible shaft cable is from about 10-feet to about 30-feet. In an embodiment, the flexible shaft cable is from about 15-feet to about 20-feet. In an embodiment, the flexible shaft cable is about 18-feet. 
     In an embodiment, the flexible shaft cable comprises a nonconductive linkage or a nonconductive section. In an embodiment, the nonconductive linkage or the nonconductive section is made of plastic or polymer resin. 
     In an embodiment, the drill adapter is adapted to be engaged by and secured in a drill. In an embodiment, the drill adapter is attached to the second end of the flexible shaft cable. 
     In an embodiment, the drill motor racking apparatus further comprises a housing. In an embodiment, the housing is disposed around the second end of the flexible shaft cable. 
     In an embodiment, the drill motor racking apparatus further comprises an ergonomic or mechanical torque limiter to limit torque to the circuit breaker. 
     In an embodiment, the drill motor racking apparatus further comprises an ergonomic torque limiter to limit torque to the circuit breaker. In an embodiment, the ergonomic torque limiter has a mechanical feedback in contact with an operator. 
     In an embodiment, the drill motor racking apparatus further comprises a mechanical torque limiter to limit torque to the circuit breaker. In an embodiment, the mechanical torque limiter is incorporated in the input to the gearbox. 
     In an embodiment, the drill motor racking apparatus further comprises one or more of an audible alarm, a notification and a visual alarm when the torque limiter reaches a limit. 
     In an embodiment, the drill motor racking apparatus further comprises one or more of an audible alarm, a notification, and a visual alarm when the torque limiter releases rotational motion to into the gearbox. 
     In an embodiment, the drill motor racking apparatus further comprises a drill. In an embodiment, the drill adapter is engaged by and secured in the drill. In an embodiment, the drill adapter is engaged by and secured in a chuck of the drill. In an embodiment, the drill is a cordless drill. In an embodiment, the drill is a corded drill. In an embodiment, the drill is hand operated. In an embodiment, the drill is machine operated. 
     In an embodiment, the drill motor racking apparatus further comprises a revolution counter capable of counting the revolutions of the drill. In an embodiment, the revolution counter counts the revolutions of the drill. 
     In an embodiment, the drill motor racking apparatus further comprises a housing or a sleeve. In an embodiment, the housing or the sleeve is disposed around the second end of the flexible shaft cable. 
     In an embodiment, the drill motor racking apparatus further comprises a nonconductive housing or a nonconductive sleeve. In an embodiment, the nonconductive housing or the nonconductive sleeve is disposed around the second end of the flexible shaft cable. In an embodiment, the nonconductive housing or the nonconductive sleeve is made of plastic or polymer resin. 
     In an embodiment, a method to rack-out a circuit breaker comprises (a) inserting a racking adapter of a drill motor racking apparatus into a racking mechanism of a circuit breaker, (b) inserting a drill adapter of the drill motor racking apparatus into a chuck of a drill, (c) operating the drill counterclockwise (or clockwise depending on the circuit breaker) to rack-out the circuit breaker, and (d) stopping operation of the drill when the circuit breaker reaches a test position or a remove position. 
     In an embodiment, step (b) further comprises tightening the chuck of the drill until the drill adapter of the drill motor racking apparatus is secure. 
     In an embodiment, step (c) further comprises securely grasping the drill in one hand of an operator and a housing or a sleeve of the drill motor racking apparatus securely in the other hand of the operator. 
     In an embodiment, a method to rack-in a circuit breaker comprises (a) inserting a racking adapter of a drill motor racking apparatus into a racking mechanism of a circuit breaker, (b) inserting a drill adapter of the drill motor racking apparatus into a chuck of a drill, (c) operating the drill clockwise (or counterclockwise depending on the circuit breaker) to rack-in the circuit breaker, and (d) stopping the operation of the drill when the circuit breaker reaches a connected position. 
     In an embodiment, step (c) further comprises securely grasping the drill in one hand of an operator and a housing or a sleeve of the drill motor racking apparatus securely in the other hand of the operator. 
     In an embodiment, the method further comprises (e) removing the racking adapter of the drill motor racking apparatus from the racking mechanism of the circuit breaker. 
     These and other objects, features and advantages will become apparent as reference is made to the following detailed description, preferred embodiments, and examples, given for the purpose of disclosure, and taken in conjunction with the accompanying drawings and appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a further understanding of the nature and objects of the present invention, reference should be made to the following detailed disclosure, taken in conjunction with the accompanying drawings, in which like parts are given like reference numerals, and wherein: 
         FIG. 1  illustrates a front, right perspective view of a typical draw-out circuit breaker; 
         FIG. 2  illustrates a rear, left perspective view of an exemplary drill motor racking apparatus, showing a first end capable of engaging the circuit breaker; 
         FIG. 3  illustrates a front, right perspective view of the drill motor racking apparatus of  FIG. 2 , showing the first end of the drill motor racking apparatus engaged to the circuit breaker; 
         FIG. 4  illustrates a left, front perspective view of the drill motor racking apparatus, showing the first end of the drill motor racking apparatus engaged to the circuit breaker and a second end of the drill motor racking apparatus being operated by an operator via a drill; 
         FIG. 5  illustrates a flow chart of a method to rack-out circuit breaker; and 
         FIG. 6 . Illustrates a flowchart of a method to rack-in a circuit breaker. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     The following detailed description of various embodiments of the present invention references the accompanying drawings, which illustrate specific embodiments in which the invention can be practiced. While the illustrative embodiments of the invention have been described with particularity, it will be understood that various other modifications will be apparent to and can be readily made by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is not intended that the scope of the claims appended hereto be limited to the examples and descriptions set forth herein but rather that the claims be construed as encompassing all the features of patentable novelty which reside in the present invention, including all features which would be treated as equivalents thereof by those skilled in the art to which the invention pertains. Therefore, the scope of the present invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled. 
     In the following detailed description and the attached drawings, specific details are set forth to provide a thorough understanding of the present disclosure. However, those skilled in the art will appreciate that the present disclosure may be practiced, in some instances, without such specific details. In other instances, well-known elements have been illustrated in schematic or block diagram form in order not to obscure the present disclosure in unnecessary detail. Additionally, for the most part, specific details, and the like, have been omitted inasmuch as such details are not considered necessary to obtain a complete understanding of the present disclosure, and are considered to be within the understanding of persons of ordinary skill in the relevant art. 
     Apparatus for Drill Motor Racking of Switchgear 
       FIG. 1  illustrates a front, right perspective view of a typical draw-out circuit breaker  100 ;  FIG. 2  illustrates a rear, left perspective view of an exemplary drill motor racking apparatus  200 , showing a first end capable of engaging the circuit breaker  100 ;  FIG. 3  illustrates a front, right perspective view of the drill motor racking apparatus  200  of  FIG. 2 , showing the first end of the drill motor racking apparatus  200  engaged to the circuit breaker  100 ; and  FIG. 4  illustrates a left, front perspective view of the drill motor racking apparatus  200 , showing the first end of the drill motor racking apparatus  200  engaged to the circuit breaker  100  and a second end of the drill motor racking apparatus  200  being operated by an operator. 
     As shown in  FIG. 1 , the circuit breaker  100  comprises a racking mechanism  101 . 
     In an embodiment, the circuit breaker  100  may be any suitable circuit breaker. For example, a suitable circuit breaker includes, but is not limited to, a draw-out circuit breaker. In an embodiment, the circuit breaker  100  may be a Cutler Hammer Westinghouse Low Voltage AC Power Circuit Breaker, or any equivalent thereof. 
     In an embodiment, the racking mechanism  101  may be any suitable mechanism to rack-in or rack-out the circuit breaker. For example, a suitable racking mechanism  101  includes, but is not limited to, a racking screw, a racking socket, or any variation thereof. In an embodiment, the racking mechanism  101  may be a racking screw. In an embodiment, the racking mechanism  101  may be a racking socket (not shown). 
     In an embodiment, the racking mechanism  101  may comprise one or more flats  101   a.  In an embodiment, the racking mechanism  101  may comprise one or more flats  101   a  on the racking screw. In an embodiment, the racking mechanism  101  may comprise one or more flats on the racking socket (not shown). 
     As shown in  FIGS. 2 and 4 , a drill motor racking apparatus  200  comprises a racking adapter/engagement head  203 , a gearbox  201 , a torque limiter  204 , a flexible shaft cable  205  and a drill adapter  207 . 
     In an embodiment, the drill motor racking apparatus  200  may be portable. In an embodiment, the drill motor racking apparatus  200  may be stationary. 
     In an embodiment, the drill motor racking apparatus  200  has a first end and a second end. In an embodiment, the first end of the drill motor racking apparatus  200  has a racking adapter/engagement head  203 . 
     In an embodiment, the racking adapter/engagement head  203  comprises a socket  202 . In an embodiment, the racking adapter/engagement head  203  may comprise one or more flats  202   a  on the socket  202 . 
     In an embodiment, the racking adapter/engagement head  203  comprises a shaft (not shown). In an embodiment, the racking adapter/engagement head  203  may comprise one or more flats on the shaft (not shown). 
     In an embodiment, the racking adapter/engagement head  203  and the socket  202  may be geometrically designed to engage a racking mechanism/racking screw  101  of the circuit breaker  100 . In an embodiment, the racking adapter/engagement head  203  in combination with the socket  202  may be designed to engage the racking mechanism/racking screw  101  of the circuit breaker  100  and to provide a mechanical method to counteract the anti-torque that is experienced by the racking adapter/engagement head  203  as the circuit breaker  100  is racked. 
     As shown in  FIG. 2 , the racking adapter/engagement head  203  may be installed by aligning the racking adapter/engagement head  203  and socket  202  to the racking screw  101  of the circuit breaker  100 . It may be necessary to rotate the inner core of the flexible shaft cable  205  a few turns so that the socket  202  will align with one or more flats  101   a  on the racking screw  101  of the circuit breaker  100 . The racking adapter/engagement head  203  is then fully inserted so that the socket  202  is fully engaged to the racking mechanism/racking screw  101  of the circuit breaker  100 . 
     In an embodiment, the racking adapter/engagement head  203  may be held engaged to the racking screw  101  of the circuit breaker  100  by any suitable engagement means. For example, a suitable engagement means includes, but not limited to, a bracket, a friction fit (e.g., between physical shape and/or openings of the racking adapter/engagement head  203  and physical shape and/or openings of racking screw  101 ), a latch, a magnet, and combinations thereof. In an embodiment, the racking adapter/engagement head  203  may be held engaged to the racking screw  101  of the circuit breaker  100  by a friction fit. 
     In an embodiment, the gearbox  201  has an input and an output. In an embodiment, the gearbox  201  may be incorporated between the flexible shaft cable  205  and the racking adapter/engagement head  203  to provide a torque multiplication required to rack the circuit breaker  100 . 
     In an embodiment, a mechanical torque limiter  204  may be incorporated into the input of the gearbox  201  and designed to limit torque to the racking screw  101  of the draw-out circuit breaker  100  so that the circuit breaker  100  is not damaged during the remote racking process. 
     As indicated in  FIG. 3 , the torque limiter  204  may be seen rotating during the breaker racking operation. When the circuit breaker  100  is fully racked-in or racked-out (depending which direction the circuit breaker  100  is being racked), the torque limiter  204  will release the rotational torque to the gearbox  201 , thus limiting the torque being applied to the racking screw  101  of the draw-out circuit breaker  100 . 
     In an embodiment, an ergonomic torque limiter may incorporated into the drill motor racking apparatus  200  and designed to limit torque to the racking screw  101  of the draw-out circuit breaker  100  so that the circuit breaker  100  is not damaged during the remote racking process. In an embodiment, the ergonomic torque limiter has a mechanical feedback in contact with an operator (e.g., arm, body, hand, shoulder of the operator). 
     In an embodiment, the drill motor racking apparatus  200  further comprises one or more of an audible alarm, a notification and a visual alarm when the torque limiter  204  reaches a limit. In an embodiment, the operator may be able to hear the audible alarm, read the notification or see the visual alarm from a distance to determine when the torque limiter  204  has reached the limit. 
     In an embodiment, the drill motor racking apparatus  200  further comprises clear or colorful labeling on the outer surface of the torque limiter  204 . In an embodiment, the operator may be able to see the clear or colorful labeling from a distance to determine when the torque limiter  204  releases the rotational motion to into the gearbox  201 . 
     In an embodiment, the flexible shaft cable  205  may be any suitable length as required by the application. For example, a suitable length may be from about 10-feet to about 30-feet, and any range or value there between. In an embodiment the flexible shaft cable  205  may be about 18-feet. 
     In an embodiment, the flexible shaft cable  205  comprises a nonconductive linkage or a nonconductive section to create a break in conductivity such that the operator may be insulated from an arc flash or an electrical discharge by the nonconductive linkage or section. 
     In an embodiment, the nonconductive linkage or the nonconductive section may be made of any suitable nonconductive material. For example, a suitable nonconductive material includes, but is not limited to, a nonmetallic material, and combinations thereof. In an embodiment, the nonconductive linkage or the nonconductive section may be made from a plastic or a polymer resin. 
     In an embodiment, the flexible shaft cable  205  has a first end and a second end. In an embodiment, a racking adapter/engagement head  203  may be connected to the first end of the flexible shaft cable. In an embodiment, the gearbox  201  is incorporated between the flexible shaft cable  205  and the racking adapter/engagement head  203  to provide a torque multiplication required to rack the circuit breaker. 
     In an embodiment, a drill adapter  207  may be attached to the second end of the flexible shaft cable  205 . 
     In an embodiment, the flexible shaft cable  205  comprises a housing or a sleeve  208 . In an embodiment, the housing or the sleeve  208  may be disposed around the second end of the flexible shaft cable  205 . 
     In an embodiment, the flexible shaft cable  205  comprises a nonconductive housing or a nonconductive sleeve  208 . In an embodiment, the nonconductive housing or the nonconductive sleeve  208  may be disposed around the second end of the flexible shaft cable  205 . 
     In an embodiment, the housing or the sleeve  208  may be made of any suitable non-conductive material. For example, a suitable nonconductive material includes, but are not limited to a nonmetallic material, and combinations thereof. In an embodiment, the housing or the sleeve  208  may be made from a plastic or a polymer resin. 
     In an embodiment, the drill motor racking apparatus  200  further comprises a drill  206 . 
     In an embodiment, the drill  206  may be any suitable commercially available drill or custom designed drill. For example, a suitable drill includes, but is not limited to, a corded drill (e.g., house powered at household current and voltage), a cordless drill (e.g., battery powered at battery current and voltage), a hand-held drill, a machine operated drill, and combinations thereof. In an embodiment, the drill  206  may be a Makita 18V ½-inch cordless drill. 
     In an embodiment, the drill  206  may be connected to the second end of the flexible shaft cable  205  and is used by the operator to effect the rotational motion on the flexible shaft cable  205  to remotely rack the circuit breaker  100 . 
     In an embodiment, the drill motor racking apparatus  200  further comprises a revolution counter (not shown) capable of counting the revolutions of the drill  206 . In an embodiment, the operator may be able to know the number of revolutions required to rack-out the circuit breaker  100 , and, therefore, the operator may be able to know the number of revolutions should be required to rack-in the circuit breaker  100 . 
     As shown in  FIG. 4 , the drill motor racking apparatus  200  may be installed on circuit breaker  100  and operated by an operator via the drill  206 , as discussed further below. 
     When the circuit breaker  100  is fully racked-in or racked-out (depending which direction the circuit breaker  100  is being racked), the operator may be able to detect reduction in torque being provided by the drill  206 . 
     Method of Using Apparatus for Drill Motor Racking of Switchgear 
     Method to Rack-Out Circuit Breaker 
     As shown in  FIGS. 4 and 5 , a method to rack-out a circuit breaker  500  comprises: (a) an operator inserts a racking adapter of a drill motor racking apparatus into a racking mechanism of a circuit breaker  505 , (b) the operator inserts a drill adapter of the drill motor racking apparatus into a chuck of a drill  510 , (c) the operator operates the drill counterclockwise (or clockwise depending on the circuit breaker) to rack-out the circuit breaker  515 , and (d) the operator stops operation of the drill when the circuit breaker reaches a test position or a remove position  520 . 
     In an embodiment, step (a)  505  comprises (a-1) an operator presses and holds a trip button on a circuit breaker to expose a racking mechanism. 
     In an embodiment, step (a)  505  comprises (a-2) the operator identifies a racking adapter of a drill motor racking apparatus. 
     In an embodiment, step (a)  505  comprises (a-3) the operator inserts the racking adapter of the drill motor racking apparatus into a racking mechanism of a circuit breaker. In an embodiment, step (a)  505  comprises (a-3) the operator inserts the racking adapter of the drill motor racking apparatus into a racking mechanism of a circuit breaker to fully engage the racking mechanism. In an embodiment, step (a)  505  comprises (a-3) the operator inserts the racking adapter of the drill motor racking apparatus into a racking mechanism of a circuit breaker to fully engage the racking mechanism by pushing the racking adapter straight in. 
     In an embodiment, step (b)  510  comprises (b-1) the operator identifies a drill adapter of a drill motor racking apparatus. 
     In an embodiment, step (b)  510  comprises (b-2) the operator inserts the drill adapter of the drill motor racking apparatus into a chuck of a drill. 
     In an embodiment, step (b)  510  comprises (b-3) the operator tightens the chuck of the drill until the drill adapter of the drill motor racking apparatus is secure in the chuck of the drill. 
     In an embodiment, step (c)  515  comprises (c-1) the operator securely grasps the drill in one hand and a housing or a sleeve of the drill motor racking apparatus securely in the other hand. 
     In an embodiment, step (c)  515  comprises (c-2) the operator operates the drill counterclockwise (or clockwise depending on the circuit breaker) to rack-out the circuit breaker. 
     In an embodiment, step (d)  520  comprises (d-1) the operator may stops operation of the drill when the circuit breaker reaches the test position. In an embodiment, step (d) comprises (d-2) the operator may stops operation of the drill when the circuit breaker reaches the remove position. 
     Method to Rack-In Circuit Breaker 
     As shown in  FIGS. 4 and 6 , a method to rack-in a circuit breaker  600  comprises: (a) an operator inserts a racking adapter of a drill motor racking apparatus into a racking mechanism of a circuit breaker  605 , (b) the operator inserts a drill adapter of the drill motor racking apparatus into a chuck of a drill  610 , (c) the operator operates the drill clockwise (or counterclockwise depending on the circuit breaker) to rack-in the circuit breaker  615 , (d) the operator stops the operation of the drill when the circuit breaker reaches a connected position  620 . 
     In an embodiment, step (a)  605  comprises (a-1) an operator presses and holds a trip button on a circuit breaker to expose a racking mechanism. 
     In an embodiment, step (a)  605  comprises (a-2) the operator identifies a racking adapter of a drill motor racking apparatus. 
     In an embodiment, step (a)  605  comprises (a-3) the operator inserts the racking adapter of the drill motor racking apparatus into a racking mechanism of a circuit breaker. In an embodiment, step (a)  605  comprises (a-3) the operator inserts the racking adapter of the drill motor racking apparatus into a racking mechanism of a circuit breaker to fully engage the racking mechanism. In an embodiment, step (a)  605  comprises (a-3) the operator inserts the racking adapter of the drill motor racking apparatus into a racking mechanism of a circuit breaker to fully engage the racking mechanism by pushing the racking adapter straight in. 
     In an embodiment, step (b)  610  comprises (b-1) the operator identifies a drill adapter of a drill motor racking apparatus. 
     In an embodiment, step (b)  610  comprises (b-2) the operator inserts the drill adapter of the drill motor racking apparatus into a chuck of a drill. 
     In an embodiment, step (b)  610  comprises (b-3) the operator tightens the chuck of the drill until the drill adapter of the drill motor racking apparatus is secure in the chuck of the drill. 
     In an embodiment, step (c)  615  comprises (c-1) the operator securely grasps the drill in one hand and a housing or a sleeve of the drill motor racking apparatus securely in the other hand. 
     In an embodiment, step (c)  615  comprises (c-2) the operator operates the drill clockwise (or counterclockwise depending on the circuit breaker) to rack-in the circuit breaker. 
     In an embodiment, step (d)  620  comprises (d-1) the operator stops operation of the drill when the circuit breaker reaches a connected position. 
     In an embodiment, the method further comprises (e) the operator removes the racking adapter of the drill motor racking apparatus from the racking mechanism of the circuit breaker  625 . 
     In an embodiment, step (e)  625  comprises (e-1) the operator loosens the chuck of the drill until the drill adapter of the drill motor racking apparatus is loose in the chuck of the drill. 
     In an embodiment, step (e)  625  comprises (e-2) the operator removes the drill adapter of the drill motor racking apparatus from the chuck of the drill. 
     In an embodiment, step (e)  625  comprises (e-3) the operator remove the racking adapter of the drill motor racking apparatus from the racking mechanism of the circuit breaker. In an embodiment, step (e)  625  comprises (e-3) the operator removes the racking adapter of the drill motor racking apparatus from the racking mechanism of the circuit breaker to fully disengage the racking mechanism. In an embodiment, step (e)  625  comprises (e-3) the operator removes the racking adapter of the drill motor racking apparatus from the racking mechanism of the circuit breaker to fully disengage the racking mechanism by pulling the racking adapter straight out. 
     Although the preceding description has been described herein with reference to particular circuits and embodiments, it is not intended to be limited to the particulars disclosed herein; rather, it extends to all functionally equivalent structures, methods, and uses, such as are within the scope of the appended claims. 
     The embodiments and examples set forth herein are presented to best explain the present invention and its practical application and to thereby enable those skilled in the art to make and utilize the invention. However, those skilled in the art will recognize that the foregoing description and examples have been presented for the purpose of illustration and example only. The description as set forth is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching without departing from the spirit and scope of the following claims. The invention is specifically intended to be as broad as the claims below and their equivalents. 
     Definitions 
     As used herein, the terms “a,” “an,” “the,” and “said” means one or more, unless the context dictates otherwise. 
     As used herein, the term “about” means the stated value plus or minus a margin of error, or plus or minus 10% if no method of measurement is indicated. 
     As used herein, the term “or” means “and/or” unless explicitly indicated to refer to alternatives only or if the alternatives are mutually exclusive. 
     As used herein, the terms “comprising,” “comprises,” and “comprise” are open-ended transition terms used to transition from a subject recited before the term to one or more elements recited after the term, where the element or elements listed after the transition term are not necessarily the only elements that make up the subject. 
     As used herein, the terms “containing,” “contains,” and “contain” have the same open-ended meaning as “comprising,” “comprises,” and “comprise,” provided above. 
     As used herein, the terms “having,” “has,” and “have” have the same open-ended meaning as “comprising,” “comprises,” and “comprise,” provided above. 
     As used herein, the terms “including,” “includes,” and “include” have the same open-ended meaning as “comprising,” “comprises,” and “comprise,” provided above. 
     As used herein, the phrase “consisting of” is a closed transition term used to transition from a subject recited before the term to one or more material elements recited after the term, where the material element or elements listed after the transition term are the only material elements that make up the subject. 
     As used herein, the term “simultaneously” means occurring at the same time or about the same time, including concurrently. 
     INCORPORATION BY REFERENCE 
     All patents and patent applications, articles, reports, and other documents cited herein are fully incorporated by reference to the extent they are not inconsistent with this invention.