Patent Publication Number: US-2020281066-A1

Title: Connector in a Plasma Arc Torch System

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of and priority to U.S. Provisional Patent Application No. 62/729,540, filed Sep. 11, 2018, the entire contents of which are owned by the assignee of the instant application and incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present invention generally relates to a quick connect and disconnect connector assembly for a plasma arc torch system. 
     BACKGROUND 
     Thermal processing torches, such as plasma arc torches, are widely used in the heating, cutting, gouging and marking of materials. A plasma arc torch generally includes an electrode, a nozzle having a central exit orifice mounted within a torch body, electrical connections, passages for cooling, and passages for arc control fluids (e.g., plasma gas). Optionally, a swirl ring is employed to control fluid flow patterns in the plasma chamber formed between the electrode and the nozzle. In some torches, a retaining cap can be used to maintain the nozzle and/or swirl ring in the plasma arc torch. In operation, the torch produces a plasma arc, which is a constricted jet of an ionized gas with high temperature and sufficient momentum to assist with removal of molten metal. 
     A connector assembly is generally used to couple a thermal processing torch (e.g., a plasma arc torch) via one or more leads to an operating system (e.g., a power/gas supply of a plasma arc system), which is configured to provide fluids, signals and/or power to the torch to support a desired torch operation. Because plasma arc systems are usable in a variety of applications and processes across a variety of environments, different torches and/or leads may be needed to support the different applications and processes. Thus, torches and/or leads need to be quickly connected and disconnected from the plasma arc system for easy replacement while avoiding long periods of downtime and maintaining reliable leak free connections for power, fluids and signals. 
     Even though connections that enable quick torch connect and disconnect relative to power supplies exist in today&#39;s market, they present challenges in operation, including creating signal noise issues, unwanted pressure drops, improper torch-to-power-supply connections, and less than desirable creepage and clearance between power and signal wires. Further, the pin arrangements in the existing connection designs limit torch functionality and expansion opportunities because these designs do not have space to accommodate additional pins supporting, for example, radio-frequency identification (RFID) communication, additional pilot current flow, increased power supply, additional gas control functions, torch height control and lead length indexing between the power supply and the torch. Existing connection designs also do not have pins with increased diameters for larger and more varied power ranges and signals. 
     Thus, there is a need for connector assembly designs that remedy these deficiencies while supporting quick connect and disconnect of a plasma arc torch from a plasma arc system. Specifically, there is a need for a connector assembly design that accommodates more pins to convey additional communication signals between a plasma arc torch and a plasma arc system while maintaining signal insulation and signal integrity among the pins. 
     SUMMARY 
     The present invention provides various designs for a connector assembly that creates a quick disconnect system with signal and fluid ports. The connector assembly also offers more operational capabilities, meets stricter design requirements, and includes optimized spacing and orientation to accommodate additional and/or varied pins and signals without creating interference or comprising the integrity of the connection. For example, the connector assembly of the present invention prevents noise interference and improper installations and/or connections, reduces pressure drops, and improves robustness of the connections. In some embodiments, such a torch assembly includes a single retention mechanism for quick connect and disconnect. In some embodiments, the torch assembly divides the pins into zones of like pins that are circumferentially spaced relative to one another to maximize creepage distance, thus reducing current creepage in a confined space. In some embodiments, the torch assembly includes blades and other hindrance structures to provide further insulation among the zones. 
     The invention, in one aspect, features a lead connector for connecting a plasma torch lead of a plasma arc torch to a power supply of a plasma cutting system. The lead connector includes a base portion and a central conduit disposed in the base portion, where the central conduit is configured to carry a gas and a torch current to the plasma arc torch. The lead connector also includes a plurality of pins disposed radially about a center of the central conduit. The plurality of pins located at a radius of between about 0.4 inches and about 0.65 inches from the center of the central conduit on a radial plane of the base portion. The plurality of pins include one or more pilot carrying pins configured to carry a pilot current to the plasma arc torch. The one or more pilot carrying pins are located from about 27 degrees to about 64 degrees about the center of the central conduit on the radial plane. The plurality of pins also include one or more control signal pins radially disposed from about 120 degrees to about 170 degrees about the center of the central conduit on the radial plane. The one or more control signal pins include at least one of a start pin configured to generate a start signal for operating the torch or a consumable sensing pin configured to generate a detection signal for sensing installation of a consumable in the torch. An angular spacing between each of the pilot carrying pins and a closest of the control signal pins is about 66 degrees or greater such that a current creepage is reduced between the pilot carrying pins and the closest of the control signal pins. 
     In another aspect, the present invention features lead connector for connecting a plasma torch lead of a plasma arc torch to a power supply of a plasma cutting system, the lead connector includes a base portion and a central conduit disposed in the base portion, where the central conduit is configured to carry a gas and a torch current to the plasma arc torch. The lead connector also includes a plurality of pins disposed radially about a center of the central conduit. The plurality of pins are located at a radius of between about 0.4 inches and about 0.65 inches from the center of the central conduit on a radial plane of the base portion. The plurality of pins include one or more pilot carrying pins radially disposed at the radius about the center of the central conduit on the radial plane. The one or more pilot carrying pins are configured to carry a pilot current to the plasma arc torch. The plurality of pins also include one or more control signal pins radially disposed at the radius about the center of the central conduit on the radial plane. The one or more control signal pins include a start pin for generating a start signal to operate the torch. An angular spacing between a pilot carrying pin and a closest of the control signal pins is not more than about 103 degrees when measured with respect to the central conduit, while a creepage distance between the pilot carrying pin and the closest control signal pin is greater than or equal to about 12.6 mm. 
     In yet another aspect, the present invention features a connector for a plasma cutting system including a plasma power supply and a plasma arc torch. The connector includes a base portion and a central conduit disposed in the base portion, where the central conduit is configured to carry a gas and a torch current to the plasma arc torch of the plasma cutting system. The connector also includes a plurality of pins disposed radially about the central conduit on a radial plane of the base portion. The plurality of pins are divided into a set of distinct circumferential zones about the central conduit. The set of distinct circumferential zones include a first zone located in a first quadrant on the radial plane of the base portion. The first zone includes one or more pilot carrying pins configured to conduct a pilot current to the plasma arc torch. The set of distinct circumferential zones also include a second zone located in a second through a fourth quadrant on the radial plane of the base portion. The second zone includes a start pin configured to generate a start signal for operating the torch. A distance between a pair of the pins in the first zone is greater than a distance between a pair of the pins in the second zone. 
     In some embodiments, each of a first pin and a last pin of the second zone is spaced radially at least 0.3 inches in arc length from respective adjacent pins of the first zone. 
     In some embodiments, the connector further includes a means for insulating the one or more pins in the second zone from the one or more pilot carrying pins in the first zone to decrease a current creepage from the pilot carrying pins to the pins in the second zone. 
     In yet another aspect, the present invention features a method of manufacturing a connector for a plasma cutting system. The connector comprises a base portion and a central conduit disposed in the base portion for carrying a gas and a torch current to a plasma arc torch of the plasma cutting system. The method includes disposing one or more pilot carrying pins radially at about 0 degrees to about 90 degrees about a center of the central conduit on a radial plane of the base portion, where the pilot carrying pins are configured to carry a pilot current to the plasma arc torch. The method also includes disposing one or more remaining pins radially at about 90 degrees to about 360 degrees about the center of the central conduit on the radial plane of the base portion, where the remaining pins include a start pin configured to generate a start signal for operating the torch. The method further includes radially spacing the pilot carrying pins and the remaining pins such that a distance between a pair of the pilot carrying pins is greater than a distance between a pair of the remaining pins. 
     In some embodiments, the method further includes inserting one or more insulative blades between the one or more pilot carrying pins and the one or more remaining pins to reduce creepage of the pilot current from the pilot carrying pins to the remaining pins. 
     In some embodiments, the method further includes disposing each of the one or more pilot carrying pins and the one or more remaining pins at a radius of between about 0.4 inches and about 0.65 inches from the center of the central conduit on the radial plane of the base portion. 
     Any of the above aspects can include one or more of the following features. In some embodiments, a line of sight spacing between a pilot carry pin and the closest of the control signal pins is about 0.6 inches. In some embodiments, the closest control signal pin comprises the consumable sensing pin. In some embodiments, a smallest angular spacing between the one or more pilot carrying pins and the one or more control signal pins is about 60 degrees. In some embodiments, a largest angular spacing between the one or more pilot carrying pins and the one or more control signal pins is about 140 degrees. In some embodiments, the one or more control signal pins further includes a power pin configured to provide voltage to the one or more control signal pins and power to a control board of the plasm arc torch. 
     In some embodiments, the reduced current creepage is further achieved using at least one of a first insulative blade disposed at about 80 degrees or a second insulative blade disposed at about 95 degrees about the center of the central conduit on the radial plane. The first or second insulative blade can be located radially between a pilot carrying pin and a control signal pin. 
     In some embodiments, each of the pilot carrying pins maintains an arc length distance of about 0.05 inches (e.g., about 0.046 inches) from an adjacent pilot carrying pin. In some embodiments, each of the control signal pins maintains an arc length distance of about 0.03 inches from an adjacent control signal pin. In some embodiments, an arc length between a pair of the pilot carrying pins is greater than an arc length between a pair of the control signal pins. 
     In some embodiments, the lead connector further comprises a key feature disposed at about 0 degrees about the center of the central conduit on the radial plane. The key feature is configured to matingly engage a key feature of a corresponding connector of a plasma power supply. The key feature can comprise at least two axial steps of the base portion shaped to identify the corresponding connector of the power supply. 
     In some embodiments, the plurality of pins further includes a plurality of data communication pins disposed radially from about 180 degrees to about 214 degrees about the opening of the central conduit on the radial plane. The plurality of data communication pins are configured to communicate data between the plasma arc torch and the power supply. In some embodiments, the plurality of pins further includes an identification pin disposed radially at about 230 degrees about the opening of the central conduit on the radial plane. The identification pin is configured to signal whether the torch is a mechanized torch or a handheld torch. In some embodiments, the plurality of pins further includes a plurality of length identification pins disposed radially from about 240 to about 300 degrees about the opening of the central conduit on the radial plane. The plurality of length identification pins configured to signal to the power supply a length of the plasma torch lead. 
     In some embodiments, the start pin is located about 147 degrees about the center of the central conduit on the radial plane. The start pin can be located between about 80 degrees and about 120 degrees from a closest of the pilot carrying pins. In some embodiments, the consumable sensing pin is located about 130 degrees about the center of the central conduit on the radial plane. In some embodiments, the one or more pilot carrying pins is located about 0 degrees to about 90 degrees about the center of the central conduit on the radial plane. For example, the one or more pilot carrying pins are located from about 20 degrees to about 70 degrees about the center of the conduit on the radial plane. In some embodiments, the one or more control signal pins are located from about 120 degrees to about 170 degrees about the center of the conduit on the radial plane. 
     In some embodiments, the plasma cutting system comprises an air cooled plasma cutting system. In some embodiments, the plurality of pins are located at a radius of about 0.55 inches from the center of the central conduit on the radial plane. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages of the invention described above, together with further advantages, may be better understood by referring to the following description taken in conjunction with the accompanying drawings. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. 
         FIG. 1  shows a connector assembly of a plasma arc cutting system that includes a lead connector and a corresponding connector receptacle, according to some embodiments of the present invention. 
         FIGS. 2 a  and 2 b    show an end view and a perspective view, respectively, of the proximal end of the lead connector of the connector assembly of  FIG. 1 , according to some embodiments of the present invention. 
         FIG. 3  shows an exemplary spacing arrangement among different features of the lead connector  102  of the connector assembly  100  of  FIG. 1 , according to some embodiments of the present invention. 
         FIG. 4  shows a perspective view of the proximal end of an exemplary lead connector without insulative blades, according to some embodiments of the present invention. 
         FIG. 5  shows a perspective view of the connector receptacle of the connector assembly of  FIG. 1 , according to some embodiments of the present invention. 
         FIG. 6  shows a cross-sectional view of a portion of the connector assembly of  FIG. 1  including the lead connector engaged to the connector receptacle, according to some embodiments of the present invention. 
         FIG. 7  shows a perspective view of another exemplary connector receptacle configured to matingly engage the lead connector of  FIG. 4 , according to some embodiments of the present invention. 
         FIG. 8  shows an exemplary method for manufacturing the lead connector of the connector assembly of  FIG. 1 , according to some embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a connector assembly  100  for a plasma arc cutting system that includes a lead connector  102  and a corresponding connector receptacle  104 , according to some embodiments of the present invention. The lead connector  102  has a proximal end  106  and a distal end  108  defining a longitudinal axis A extending therethrough. The proximal end  106  of the lead connector  102  is configured to mate with the connector receptacle  104 . In some embodiments, the connector receptacle  104  is a socket disposed on a power and/or gas supply  110  of the plasma arc cutting system. The distal end  108  of the lead connector  102  is configured to couple to a plasma arc torch (not shown) via one or more leads (not shown). Thus, upon a mating engagement with the connector receptacle  104 , the lead connector  102  can connect a plasma torch lead of a plasma arc torch to a power supply of the plasma arc cutting system. The lead connector  102 , in conjunction with the connector receptacle  104 , convey fluids, signals and/or power to the plasma arc torch. The lead connector  102  can disengage from the connector receptacle  104  with a quick actuation movement, as described in detail below. In some embodiments, the plasma arc cutting system, which comprises the connector assembly  100 , the plasma arc torch and the power/gas supply  110 , is air cooled. 
       FIGS. 2 a  and 2 b    show an end view and a perspective view, respectively, of the proximal end  106  of the lead connector  102  of the connector assembly  100  of  FIG. 1 , according to some embodiments of the present invention. As shown, the lead connector  102  includes a base portion  200  disposed at the proximal end  106  of the lead connector  102 , where the base portion  200  defines a radial plane  202  that is substantially perpendicular to the longitudinal axis A of the lead connector  102 . In some embodiments, the radial plane  202  is substantially circular. The lead connector  102  also includes a central conduit disposed in the base portion  200  such that an opening  204  of the central conduit is located on the radial plane  202  and exposed at the proximal end  106 . The central conduit opening  204 , which is located at the center  206  of the radial plane  202 , is configured to direct a gas and/or carry an electrical current (e.g., main power current) from the power and/or gas supply  110  to the plasma arc torch. Further, the lead connector  102  includes multiple ports (collectively numbered  208 ), such as in the form of protruding pins, disposed radially around the central conduit opening  204  on the radial plane  202  to convey various types of signals between the torch and the power/gas supply  110 . Each of these pins  208  is generally located off-centered, non-concentric, and non-symmetrical relative to the center  206  of the radial plane  202 . The orientation and spacing of the various pins  208  are tailored to the corresponding signals or fluids conveyed. 
     In some embodiments, the multiple pins  208  include a zone  210  of one or more pilot carrying pins, such as three pilot carrying pins  208   a - c  illustrated in  FIGS. 2 a  and  b   , generally disposed in the first quadrant (i.e., 0 to about 90 degrees) of the radial plane  202  about the center  206 . In the context of the present application, angle measurements described herein are about the center  206  of the radial plane  202  and clockwise in relation to a reference point (i.e., 0 degree), which can be where one or more key features  240  are located. The pilot carrying pins  208   a - c  can be located from about 20 degrees to about 70 degrees about the center  206  (e.g., about 27 degrees to about 64 degrees), where the first pilot carrying pin  208   a  is at about 27 degrees, the second pilot carrying pin  208   b  is at about 46 degrees and the third pilot carrying pin  208   c  is at about 64 degrees. Even though three pilot carrying pins  208   a - c  are shown in  FIGS. 2 a  and  b   , there can be more or fewer pilot carrying pins, such as one pilot carrying pin or two pilot carrying pins with the second pin as a backup. Each of these pilot carrying pins  208   a - c  is configured to carry a pilot current from the power/gas supply  110  to the plasma arc torch. 
     In some embodiments, the remaining pins  208 , which are the pins located in the second through fourth quadrants of the radial plane  202 , include a zone  212  of one or more control signal pins. For example, the zone  212  can include three control signal pins  208   e - g , configured to convey various control signals from the power/gas supply  110  to the plasma arc torch to control different aspects of operating the torch. Specifically, the zone  212  of control signal pins can include a cap sense switch pin  208   e  adapted to convey to the power/gas supply  110  an electrical signal if installation of a consumable in the torch is sensed. The zone  212  of control signal pins can also include a start pin  208   f  configured to convey a start signal to the power/gas supply  110  for commencing operation of the torch if an operator activates a trigger on the torch. The zone  212  of control signal pins can further include a power pin  208   g  configured to provide voltage (e.g., 18V) from the power/gas supply  110  to the zone  212  of control signal pins and to a control board (not shown) of the plasm arc torch configured to provide communication between the attached plasma arc torch and a digital signal processing board of the power supply  110 , detect the presence of one or more consumables in the torch, provide plasma arc current adjustment, display the status of operating parameters (e.g., current level and torch operation status and warnings) and execute user controls (e.g., disable control). In some embodiments, the zone  212  of control signal pins are generally disposed in the second quadrant (i.e., 90 to 180 degrees) of the radial plane  202  about the center  206  of the radial plane  202 . For example, they can be radially located from about 120 degrees to about 170 degrees about the center  206 , where the cap sense switch pin  208   e  is at about 130 degrees, the start pin  208   f  is at about 147 degrees, and the power pin  208   g  is at about 164 degrees. In some embodiments, the start pin  208   f  is located between about 80 degrees and about 120 degrees from the radially closest pilot carrying pin (e.g., pilot carrying pin  208   c ). 
     In some embodiments, the remaining pins  208  include a torch height adjustment pin  208   d  located on the radial plane  202  radially between the zone  210  of pilot carrying pins and the zone  212  of control signal pins, but is not a part of the zone  210  of pilot carrying pins or the zone  212  of control signal pins. For example, the torch height adjustment pin  208   d  can be located at about 90 degrees on the radial plane  202 . This pin  208   d  is configured to perform CNC height control if the lead connector  102  connects a mechanized torch to the plasma arc cutting system. The torch height adjustment pin  208   d  can measure the arc voltage (or resistance) from the ohmic contact attached to the processing head of the attached torch to the workpiece and automatically send signals to the power supply  110  to adjust the height for optimal cutting performance regardless of the workpiece material variations. 
     In some embodiments, the remaining pins  208  include a zone  222  of one or more data communication pins  208   h - j , configured to communicate different types of data between the plasma arc torch and the power/gas supply  110 . The zone  222  of data communication pins radially span from about 180 degrees to about 214 degrees about the center  206  of the radial plane  202 . Specifically, the data communication pins can include two communication lines  208   i ,  208   j , located at about 198 degrees and about 214 degrees, respectively, configured to provide RS-485 serial communication, and a ground pin  208   h , located at about 180 degrees, configured to provide a reference ground for the communication pins  208   i  and  208   j.    
     In some embodiments, the remaining pins  208  include a torch identification pin  208   k  disposed radially at about 230 degrees about the center  206  of the radial plane  202  adjacent to the zone  222  of data communication pins. The torch identification pin  208   k  is configured to signal to the power and/or gas supply  110  whether the torch connected is a mechanized torch or a handheld torch. In some embodiments, the remaining pins  208  further include a zone  224  of one or more length identification pins disposed radially from about 240 degrees to about 300 degrees about the center  206  of the radial plane  202 . As shown in  FIG. 2 a   , the length identification pins can comprise three pins  208   l ,  208   m ,  208   n , each configured to signal to the power/gas supply  110  a length of the plasma torch lead. In some embodiments, multiple length identification pins are used for generating various combinations of numbers that correspond to various lead lengths. For example if two length identification pins are used, the binary codes 0-0, 0-1 and 1-1 generated by these two pins represent different lead lengths. Therefore, even more lead lengths can be identified with the usage of three pins. In some embodiments, the remaining pins  208  further include one or more spare pins for future communication expansion usage. For example, as shown in  FIG. 2 a   , three spare pins  208   o ,  208   p ,  208   q  are located adjacent to the zone  224  of length identification pins. These three spare pins  208   o ,  208   p ,  208   q  can be located at about 300 degrees, 316 degrees and 333 degrees, respectively, about the center  206  of the radian plane  202 . 
     In another aspect, the radial arrangement of the zone  210  of pilot carrying pins relative to the remaining pins  208  is optimized to reduce current creepage. In the context of the present invention, current creepage is defined as the leakage of an electrical current across the surface of an insulator (e.g., across the radial plane  202  of the base portion  200 ) between two conductive parts (e.g., between two pins). Such a leakage current can establish a short circuit across a gap between two pins. Thus, a creepage distance between the pins needs to be sufficiently large (e.g., in compliance with the pertinent industry standard, such as IEC 50974-1 ED5) to prevent short circuiting, thereby safeguarding operator safety. Specifically, because the pilot carrying pins of zone  210  are configured to conduct high current, measures need to be taken to minimize creepage of the pilot current to the surrounding pins (i.e., maximize creepage distance). However, this consideration needs to be balanced with the competing consideration to minimize spacing among the pins  208  such that more pins  208  can be located on the radial plane  202  to provide more complex control capabilities. 
     In some embodiments, to achieve reduced current creepage among the pins  208  in compliance with the industry standard, angular spacing between the zone  210  of pilot carrying pins and the zone  212  of control signal pins is defined. For instance, angular spacing between each of the pilot carrying pins (e.g., pins  208   a - c ) in the zone  210  and a closest of the control signal pins (e.g., the cap sense switch pin  208   e ) in the zone  212  is chosen to be about 60 degrees or greater. For example, the smallest angular spacing  260  between the two zones of pins, which is the between the pilot carrying pin  208   c  at about 64 degrees and the cap sense switch pin  208   e  at about 130 degrees, is about 66 degrees. In some embodiments, a line of sight spacing between a pilot carrying pin (e.g., one of pins  208   a - c ) and the closest of the control signal pins (e.g., the cap sense switch pin  208   e ), which represents a straight line distance across the radial plane  202  between the two pins, is about 0.6 inches or greater, such as 1.2 inches. 
     In some embodiments, to minimize current creepage among the pins  208  in compliance with the industry standard, a creepage distance of greater than or equal to 12.6 mm is maintained between a pilot carrying pin (i.e., pin  208   a, b , or  c ) and the closest of the remaining pins (e.g., control signal pin  208   e ). For example, at least one insulative blade can be radially disposed between the zone  210  of pilot carrying pins and the zone  212  of control signal pins about the center  206  of the radial plane  202  to increase the creepage distance without increasing the angular spacing between the two zones. The insulative blade can be constructed from an electrically insulating material that extends longitudinally (i.e., along longitudinal axis A) to form a barrier between the zones. As shown, a first insulative blade  214  is disposed at about 80 degrees about the center  206 , immediately between the zone  210  of pilot carrying pins and the torch height adjustment pin  208   d . A second insulative blade  216  can be disposed at about 95 degrees about the center  206 , immediately between the torch height adjustment pin  208   d  and the zone  212  of control signal pins. Each of these blades  214 ,  216  is adapted to increase the creepage distance between the adjacent pins without increasing the angular spacing and arc length distance between them, thus allowing more pins to be accommodated on the radial plane  202 . For example, as shown in  FIG. 2 b   , the creepage distance  218  (i.e., the shortest surface travel distance) between the pilot carrying pin  208   c  and the height control pin  208   d  without the first insulative blade  214  is shorter than the creepage distance  220  between the two pins  208   c ,  208   d  with the first insulative blade  214  in place because the current creepage needs to travel around insulative blade  214  instead of in a straight-lined path. The same principle applies to the function of the second insulative blade  216  in terms of reducing the current creepage and/or increasing the creepage distance between the height control pin  208   d  and the consumable sensing pin  208   e . In some embodiments, the creepage distance between pins  208   c  and  208   d  is about 6.3 mm or greater. In some embodiments, the creepage distance between pins  208   d  and  208   e  is about 12.6 mm or greater. Thus, the creepage distance between any of the pilot carrying pins  208   a - c  and the consumable sensing pin  208   e  is greater than 12.6 mm. In general, the blades  214 ,  216  serve to enhance insulation between the pilot carrying pins  208   a - c  in the zone  210 , the torch height adjustment pin  208   d , and the remaining pins from one other. Further, the insulative blades  214 ,  216  create three distinct groupings of the communications pins that are spatially and physically separated from one another. The three different groupings comprise the zone  210  of pilot carrying pins  208   a - c , the torch height adjustment pin  208   d , and the remaining pins  208   e - q  located in second through fourth quadrants on the radial plane  202  (hereinafter referred to as the “residual zone”). In some embodiments, substantially the same creepage distance can be achieved by strategically arranging the pins without the insulative blades  214 ,  216  or using only one of the blades  214 ,  216 . For example, substantially the same creepage distance can be achieved by increasing the arc length spacing among the communication pins  208   c - e  for increased insulation by distance. 
     In some embodiments, an upper bound on the angular spacing between the pilot carrying pins of zone  210  and the control signal pins of zone  212  is set to maximize the number of pins that can fit on the radial plane  202 . The angular spacing between a pilot carrying pin in zone  210  and a closest of the control signal pins in zone  212  can be no more than about 103 degrees when measured with respect to the center  206 . For example, the angular spacing  262  between the pilot carrying pin  208   a  at about 27 degrees and the cap sense switch pin  208   e  at about 130 degrees is about 103 degrees. In some embodiments, the largest angular spacing between the pilot carrying pins in zone  210  and the control signal pins in zone  212  is no more than about 140 degrees when measured with respect to the center  206 . For example, this angular spacing  264 , which is between the pilot carrying pin  208   a  at about 27 degrees and the power pin  208   g  at about 164 degrees, is about 137 degrees. 
       FIG. 3  shows an exemplary spacing arrangement among different features of the lead connector  102  of the connector assembly  100  of  FIG. 1 , according to some embodiments of the present invention. In general, the pins  208  can have non-uniform spacing. For instance, the pins in some zones are more tightly grouped relative to one another in comparison to the pins in other zones, which are more spaced relative to one another. Specifically, the arc length distance between a pair of adjacent pins in one zone can be different than the arc length distance between a pair of adjacent pins in another zone. Such varied distance separates pins of different functions (e.g., pilot arc and ohmic sense contact points, gas supplies and power supply connections) from one another dependent on signal uses and needs. 
     In some embodiments, an arc length distance between a pair of adjacent pilot carrying pins in the zone  210  can be greater than an arc length distance between a pair of adjacent pins located in the residual zone. For instance, each of the pilot carrying pins in the zone  210  can maintain an arc length distance  302  of about 0.05 inches (e.g., 0.046 inches) from an adjacent pilot carrying pin, while each of the pins in the residual zone maintains an arc length distance  304  of about 0.03 inches from an adjacent pin in the same zone. In some embodiments, a pin of the residual zone (e.g., pin  208   e ) is spaced at an arc length distance of at least about 0.3 inches from the closest adjacent pilot carrying pin in the zone  210  (e.g., pilot carrying pin  208   c ). For instance, the arc length distance  312  between the pilot carrying pin  208   c  and the torch height adjustment pin  208   d , which can be separated by the first insulative blade  214 , can be about 0.12 inches, and the arc length distance  314  between the torch height adjustment pin  208   d  and the control signal pin  208   e , which can be separated by the second insulative blade  216 , can be about 0.24 inches. Thus, the shortest arc length distance between the pilot carrying zones  210  and the residual zone is about 0.36 inches. These differential spacing schemes facilitate insulation between pins and signals. 
     In some embodiments, each of the pins  208  can be located at a radius  306  of between about 0.4 inches and about 0.65 inches from the center of  206  of the radial plane  202  of the base portion  200 , such as about 0.55 inches. The radius  306  is defined as the distance between the center  206  of the radial plane  202  and the center of a pin  208 . In some embodiments, each pin  208  is dimensioned to have a diameter of about 0.012 inches, such that an inner radius  308  between the center  206  of the radial plane  202  and the inner diameter of the pin  208  is about 0.49 inches, and an outer radius  310  between the center  206  of the radial plane  202  and the outer diameter of the pin  208  is about 0.61 inches. In some embodiments, wires attached to the pins  208  have different diameters, even though the pins  208  themselves have about the same diameter. For example, wires connected to the high current pilot carrying pins in zone  210  can have a larger diameter than that of wires connected to the low current control signal pins in zone  212 . 
       FIG. 4  shows a perspective view of the proximal end of an exemplary lead connector  702  without insulative blades, according to some embodiments of the present invention. As shown, the lead connector  702  have the same set of pins  708  as the pins  208  of the lead connector  102 , where the pins  708  are disposed in a the same order and at about the same angular locations about the center  706  of the central conduit opening  704 . Specifically, the pins  708  (listed in a clockwise order relative to the one or more key feature  740 ) comprise a zone of pilot carrying pins  708   a - c , a torch height adjustment pin  708   d , a zone of control signal pins  708   e - g , a zone of data communication pins  708   h - j , a torch identification pin  708   k , a zone of length identification pin  708   l - n , and a zone of spare communication signal pins  708   o - q . In some embodiments, the only difference between the lead connector  702  and the lead connector  102  is the absence of the insulative blades  214 ,  216  in the lead connector  702 . However, the lead connector  702  can still achieve reduced creepage distance among the pins  708  without the use of an insulative blade while maximizing the number of pins that can fit on its radial plane due to the non-uniform spacing of the pins  708  as explained above with respect to  FIGS. 2 a , 2 b    and  3 . 
     As described above, the lead connector  102  of the connector assembly  100  is configured to matingly engage with the corresponding connector receptacle  104  for connecting the torch to the power/gas supply  110 . Thus, the connector receptacle  104  has a set of orientation and insulation features complementary to the features of the lead connector  102 .  FIG. 5  shows a perspective view of the connector receptacle  104  of the connector assembly of  FIG. 1 , according to some embodiments of the present invention. As shown, the connector receptacle  104  includes multiple slots (collectively numbered  402 ) disposed on a radial plane  408  at its proximal end  410  for receiving the corresponding pins  208  of the lead connector  102 . Specifically, the slots  402  include (i) a set of pilot carrying slots  402   a - c  for receiving the corresponding pilot carrying pins  208   a - c , (ii) a torch height adjustment slot  402   d  for receiving the corresponding torch height adjustment pin  208   d , (iii) a set of control signal slots  402   e - g  for receiving the corresponding control signal pins  208   e - g , (iv) a set of data communication slots  402   h - j  for receiving the corresponding data communication pins  208   h - j , (v) a torch identification slot  402   k  for receiving the corresponding torch identification pin  208   k , (vi) a set of length identification slots  402   l - n  for receiving the corresponding length identification pins  208   l - n , and (vii) a set of spare slots  402   o - q  for receiving the corresponding spare pins  208   o - q . Further, the connector receptacle  104  includes a set of blade channels  404 ,  406  for receiving at least a portion of the insulative blades  214 ,  216 , respectively of the lead connector  102 . 
     In another aspect, the lead connector  102  and the connector receptacle  104  include one or more complementary key features to ensure that only acceptable torches can be connected to the power/gas supply  110 . In some embodiments, the key features include a set of one or more steps  240  disposed relative to the radial plane  202  of the leader connector  102 , as shown in  FIGS. 2 a  and 2 b   , and a set of one or more complementary steps  440  disposed at about the same radial location on the proximal end  410  of the connector receptacle  104 , as shown in  FIG. 5 . The key features  240 ,  440  can be disposed at about 0 degrees about the center of the respective radial planes. In general, the key features  440  on the connector receptacle have unique shapes and/or arrangements for a desired current rating (e.g.,  30 A,  45 A,  65 A,  85 A,  105 A or  125 A) for the associated power supply  110 , where the shapes and/or arrangements are different from those of a connector receptacle associated with a different current rating. Thus, a connector receptacle  104  can only engage with a particular lead connector  102  if the key features  240  of that lead connector  102  have complementary shapes and/or arrangements to indicate that the torch connected thereto is suitable for use under the desired current rating. As an example, a 30A torch is associated with key features  240  on its torch connector  102  that do not complement the key features  440  of a connector receptacle  440  associate with a  125 A power supply, and therefore would not be able to connect to the more powerful power supply. 
     In some embodiments, the key features  440  of the connector receptacle  104  comprise multiple axial steps with staggered depths along the longitudinal axis of the receptacle  104 , as shown in  FIG. 5 . The axial length of each step can be unique to a particular current rating. Further, the key features  440  can be labeled for user identification and reference during connection. For example, the “3-1” label for the two axial steps of  FIG. 5  represents an index indicating the current rating of the associated power supply  110 . In some embodiments, the label is unique to a particular current rating, e.g.,  105 A. Similarly, the key features  240  of the corresponding lead connector  102  also comprise multiple complementary axial steps with staggered depths of the same axial lengths along the longitudinal axis, as shown in  FIGS. 2 a  and 2 b   . Further, the axial steps  240  can have the same label as those of the connector receptacle  104  to visually indicate to an operator that the connector  102  and the receptacle  104  are keyed to each other. In some embodiments, the axial steps  240  of the lead connector  102  can have different labels than those of the axial steps  440  of the connector receptacle  104 , but can still mate with the axial steps of the connector receptacle  104 , as long as the labels of the lead connector  102  indicate a current rating that is higher than the current rating of the connector receptacle  104 . 
       FIG. 6  shows a cross-sectional view of a portion of the connector assembly of  FIG. 1  including the lead connector  102  engaged to the connector receptacle  104 , according to some embodiments of the present invention. As shown, the key feature  440  of the connector receptacle  104  comprises two steps axially protruding or recessed relative the radial plane  408  on which the openings of the slots  402  are located. These axial steps have three axial lengths  502 ,  504 ,  506  that are specific to a particular current rating of the power supply  110 . The suitable torch for the power supply  110  has a lead connector  102  with a key feature  240  that also comprises two complementary axial steps having the same three axial lengths  502 ,  504 ,  506 . An additional or alternative protection mechanism includes each of the key features  240 ,  440  being labeled to visually identify the suitable current rating. For example, the key feature  440  of the connector receptacle  104  can have a set of one or more numbers etched on the tabs  508 ,  510  of the axial steps, where the numbers correspond to a particular current rating. Similarly, the key feature  240  of the complementary lead connector  102  can have a second set of numbers etched on the tabs  512 ,  514  of its axial steps. In some embodiments, the second set of numbers of the lead connector  102  corresponds to a current rating that is the same as or higher than the current rating associated with the set of numbers for the connector receptacle  104 . This is to prevent a lower amperage torch from being connected into a higher amperage rated power supply to avoid over-heating of the torch leads or causing other damage due to such a faulty connection. For example, a “2-0” torch (e.g., a  3   1 - 45 A rated torch) can&#39;t be plugged into a “3-0” power supply (e.g., a  65 A or  85 A power supply system). However, a “3-0” torch can be plugged to a “2-0” power supply.  FIG. 6  also shows a table  520  of exemplary indices mapped to different current ratings. 
       FIG. 7  shows a perspective view of another exemplary connector receptacle  804  configured to matingly engage the lead connector  702  of  FIG. 4 , according to some embodiments of the present invention. As shown, the connector receptacle  804  includes multiple slots  802  for receiving the corresponding pins  708  of the lead connector  702 . Specifically, the slots  802  include (i) a set of pilot carrying slots  802   a - c  for receiving the corresponding pilot carrying pins  708   a - c , (ii) a torch height adjustment slot  802   d  for receiving the corresponding torch height adjustment pin  708   d , (iii) a set of control signal slots  802   e - g  for receiving the corresponding control signal pins  708   e - g , (iv) a set of data communication slots  802   h - j  for receiving the corresponding data communication pins  708   h - j , (v) a torch identification slot  802   k  for receiving the corresponding torch identification pin  708   k , (vi) a set of length identification slots  802   l - n  for receiving the corresponding length identification pins  708   l - n , and (vii) a set of spare slots  802   o - q  for receiving the corresponding spare pins  708   o - q . The connector receptacle  804 , however, does not include any blade channel due to the absence of insulative blades in the corresponding lead connector  702 . In some embodiments, the key features  740  of the lead connector  702  complement the key features  840  of the lead receptacle  804  in the same fashion as the key features  240 ,  440  of the lead connector  102  and lead receptacle  104  described above, for the purpose of ensuring that only acceptable torches can be connected to the power/gas supply  110 . In some embodiments, the only difference between the lead receptacle  804  and the lead receptacle  104  is the absence of the blade channels  404 ,  406  in the lead receptacle  804 . 
       FIG. 8  shows an exemplary method  600  for manufacturing the lead connector  102  of the connector assembly  100  of  FIG. 1 , according to some embodiments of the present invention. At step  602 , the method  600  involves disposing one or more current carrying pins  208   a - c  radially about 0 degrees to about 90 degrees around the center  206  of the central conduit opening  204  on the radial plane  202  at the base portion  200  of the lead connector  102 . The pilot carrying pins  208   a - c , which form the pilot carrying zone  210 , are configured to carry a pilot current from the power/gas supply  110  to the plasma arc torch attached to the lead connector  102 . At step  604 , one or more remaining pins are radially disposed at about 90 degrees to about 360 degrees about the center  206  of the central conduit opening  204  on the radial plane  202 . These remaining pins can include the torch height adjustment pin  208   d  and a residual zone of pins  208   e - q , which can be further divided into several zones including the control signal zone  212  encompassing pins  208   e - 208   g , the data communication zone  222  encompassing pins  208   h - j , and the length identification zone  224  encompassing pins  208   l - n . These pins include at least the start pin  208   f  configured to generate a start signal for operating the torch. At step  606 , the pins  208  are radially spaced in a non-uniform fashion such that the arc length distance among the pins of one zone is different from the arc length distance among the pins of another zone. For example, the arc length distance between a pair of the pilot carrying pins in the zone  210  is greater than the arc length distance between a pair of the pins in the residual zone. In some embodiments, one or more insulative blades are inserted between the pilot carrying pins  208   a - c  in the zone  210  and the torch height adjustment pin  208   d  and/or between the torch height adjustment pin  208   d  and the pins  208   e - q  in the residual zone to maximize creepage distance without increasing the arc length distance among the pins  208 . As understood by a person of ordinary skill in the art, a similar method can be adapted for manufacturing the lead connector  702  of  FIG. 4 , according to some embodiments of the present invention. 
     In general, the connection and disconnection between the lead connector  102  and the connector receptacle  104  is quick and only involves an actuating motion for inserting the pins  208  into or retracting the pins  208  from the slots  402  while maintaining alignment of the key features  240 ,  440 . The same advantage also applies to the lead connector  702  and the connector receptacle  804 . Other advantages associated with the connector designs of the present invention include maximization of creepage distance among the communication ports while minimizing the size of the connector assembly, reduced interference in the lead due to strategic grouping and non-uniform placement of the communication ports, and improved safety by preventing any connection between a mismatched torch and power supply. 
     Within the context of the present invention, the term “about” in relation to a particular degree value can be constructed as covering a range of ±four-degree deviation from the particular degree value. The term “about” in relation to a numerical value can be constructed as covering a range of ±2% deviation from the particular numerical value. It should be understood that various aspects and embodiments of the invention can be combined in various ways. Based on the teachings of this specification, a person of ordinary skill in the art can readily determine how to combine these various embodiments. Modifications may also occur to those skilled in the art upon reading the specification.