Patent Publication Number: US-2022216642-A1

Title: Locking combination outlet module and power distribution unit incorporating the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a continuation of U.S. application Ser. No. 16/819,568, filed Mar. 16, 2020, titled “LOCKING COMBINATION OUTLET MODULE AND POWER DISTRIBUTION UNIT INCORPORATING THE SAME”, the entirety of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure is generally directed to outlet modules, and particularly modules that include locking features and those that can accommodate multiple plug types. More specifically the disclosure is directed to power distribution units incorporating one or more such modules. 
     BACKGROUND 
     A conventional power distribution unit (PDU) is an assembly of electrical outlets (also called receptacles) that receive electrical power from a source and distribute the electrical power to one or more separate electronic appliances. Each such PDU assembly has a power input that receives power from one or more power sources, and power outlets that may be used to provide power to one or more electronic appliances. PDUs are used in many applications and settings such as, for example, in or on electronic equipment racks. 
     A common use of PDUs is supplying operating power for electrical equipment in computing facilities, such as enterprise data centers, multi-tenant hosting environments like colocation facilities, cloud computing, and other data center types. Such computing facilities may include electronic equipment racks that comprise rectangular or box-shaped housings sometimes referred to as a cabinet or a rack and associated components for mounting equipment, associated communications cables, and associated power distribution cables. Electronic equipment may be mounted in such racks so that the various electronic devices (e.g., network switches, routers, servers and the like) are mounted vertically, one on top of the other, in the rack. One or more PDUs may be used to provide power to the electronic equipment. Multiple racks may be oriented side-by-side, with each containing numerous electronic components and having substantial quantities of associated component wiring located both within and outside of the area occupied by the racks. Such racks commonly support equipment that is used in a computing network for an enterprise, referred to as an enterprise network. 
     Various different equipment racks may have different configurations, including different locations of and different densities of equipment within the racks. Equipment in modern data center racks, most commonly servers, storage, and networking devices, typically have C14 or C20 plugs, requiring C13 or C19 outlets on a corresponding rack&#39;s PDU. There is often a mixture of how many and where on the PDU each C13 or C19 outlet is positioned in order to best match the equipment. PDU equipment suppliers commonly manufacture many variations of PDU&#39;s that have different mixes of C13 and C19 outlet configurations to meet the demands of the data center market. It is also common for the servers, storage, and network equipment to be changed every three to five years, which then may require a different outlet configuration on the PDU. 
     Enterprise data centers, multi-tenant hosting environments like colocation facilities, cloud computing, and other data center types are often critical for business operations. Therefore, it is important that the electrical connections between a PDU and its associated servers, storage, and network equipment is secure in order to maintain equipment up time to reliably support the enterprise users. 
     SUMMARY 
     Locking combination outlet modules and PDUs incorporating those modules are disclosed herein. The disclosed locking modules provide flexibility in connecting to various combinations of e.g., C13 and C19 outlets, as well as securing those connections against being inadvertently disconnected. In a representative embodiment, an outlet module can comprise a module housing having a base surface and a sidewall extending therefrom to at least partially surround an interior region. Multiple outlet cores can extend from the base surface and at least one latch lever is pivotably coupled to the sidewall and adjacent a corresponding one of the multiple outlet cores. The latch lever is movable between a first position, wherein the at least one latch lever is capable of engaging a mating plug and a second position, wherein the at least one latch lever is disengaged from the plug. 
     In another representative embodiment, an outlet module can comprise a module housing having a base surface and a sidewall extending therefrom to at least partially surround an interior region, wherein at least the base surface and the sidewall comprise an integrally molded unitary body. Multiple outlet cores can extend from the base surface with multiple latch levers pivotably coupled to the sidewall outside the interior region. Each latch lever can be positioned adjacent a corresponding one of the multiple outlet cores and movable between a latch position and an unlatch position. Multiple resilient members are each positioned between the sidewall and a corresponding one of the multiple latch levers to bias the corresponding latch lever toward the latch position. 
     In a further representative embodiment, a power distribution unit can comprise a housing, a power input coupled with the housing and connectable to an external power source, and at least one outlet module located at least partially within the housing and connected to the power input. The outlet module can include a module housing comprising a base surface and a sidewall extending therefrom to at least partially surround an interior region. Multiple outlet cores can extend from the base surface. Multiple latch levers can be pivotably coupled to the sidewall outside the interior region, wherein each latch lever is positioned adjacent a corresponding one of the multiple outlet cores and moveable between an unlatch position and a latch position. The latch levers are positioned to engage a mating plug when the latch lever is in the latch position. 
     In one aspect of the disclosed technology, each of the multiple latch levers pivots about a common pivot shaft. In some embodiments, each latch lever pivots about its own individual shaft. In another aspect of the disclosed technology, each of the multiple outlet cores can comprise a separate outlet core fastened to the base surface. In a further aspect of the disclosed technology, at least the base surface and the sidewall can comprise an integrally molded unitary body. In yet another aspect of the disclosed technology, the at least one latch lever can further comprise a tooth portion extending into the interior region and positioned to engage a mating plug when the at least one latch lever is in the latch position. In one aspect of the disclosed technology, the module can further comprise a resilient member, e.g., a compression spring, positioned between the sidewall and the at least one latch lever to bias the at least one latch lever toward the latch position. In another aspect of the disclosed technology, the at least one latch lever can comprise a release tab, a tooth portion, a pivot bore positioned therebetween, and wherein the resilient member is positioned between the release tab and the pivot bore. In one aspect of the disclosed technology, the multiple outlet cores can comprise at least one IEC C13 outlet core. 
     In one aspect of the disclosed technology, the multiple outlet cores can comprise at least one combination outlet core having a plurality of apertures configured to receive mating terminals corresponding to both an IEC C14 connector and an IEC C20 connector, the combination outlet core having an outer surface configured to mate with an IEC C14 connector, and a plurality of electrical terminals each positioned in a corresponding one of the apertures and configured to connect with the mating terminals corresponding to both an IEC C14 connector and an IEC C20 connector. In a further aspect of the disclosed technology, the plurality of apertures can each comprise at least two intersecting cross-wise slots. In yet another aspect of the disclosed technology, the plurality of apertures can each have a T-shaped configuration. 
     The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The concepts and specific examples disclosed herein may be readily used as a basis for modifying or designing other structures for carrying out the same or similar purposes of the present disclosure. Such equivalent constructions do not depart from the spirit and scope of the appended claims. Features which are believed to be characteristic of the concepts disclosed herein, both as to their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purpose of illustration and description only, and not as a definition of the limits of the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A further understanding of the nature and advantages of the present technology may be realized by reference to the following drawings. In the appended figures, similar components or features may have the same reference label. 
         FIG. 1  is an illustration of a power distribution unit incorporating locking combination outlet modules in accordance with an embodiment of the disclosed technology; 
         FIG. 2  is a partial isometric view of a locking combination outlet module according to a representative embodiment positioned in a PDU housing; 
         FIG. 3  is an isometric view of the outlet module shown in  FIG. 2 , as viewed from the lever side; 
         FIG. 4  is an isometric view of the outlet module shown in  FIGS. 2 and 3 , as viewed from the bottom and opposite the levers; 
         FIG. 5  is a partial isometric view of the outlet module shown in  FIGS. 2-4 , as viewed from the top; 
         FIG. 6A  is an isometric view of a combination outlet core according to a representative embodiment, as viewed from the top; 
         FIG. 6B  is an isometric view of the combination outlet core shown in  FIG. 6A  as viewed from the bottom; 
         FIG. 7  is a top plan view of the outlet module shown in  FIGS. 2-5 ; 
         FIG. 8  is a cross-sectional isometric view of the outlet module taken about line  8 - 8  in  FIG. 7 ; 
         FIG. 9  is an isometric view of a representative latch lever as shown in  FIGS. 7 and 8 ; 
         FIG. 10  is a side view of a locking combination outlet module with representative power cords connected thereto; 
         FIG. 11  is a cross-sectional view of the outlet module and cords taken about line  11 - 11  in  FIG. 10 ; 
         FIG. 12  is a cross-sectional view of the outlet module and cords taken about line  12 - 12  in  FIG. 10 ; 
         FIG. 13  is a cross-sectional view of a latch lever arrangement according to another representative embodiment; 
         FIG. 14  is an isometric view of a locking combination outlet module according to another representative embodiment; 
         FIG. 15  is a partial isometric view of the locking combination outlet module shown in  FIG. 14  as viewed from the top and opposite the levers; 
         FIG. 16  is a partial isometric view of the locking combination outlet module shown in  FIG. 14  as viewed from the lever side; 
         FIG. 17  is an isometric view of a lock lever assembly according to a representative embodiment; 
         FIG. 18  is an illustration of a power distribution unit incorporating locking combination outlets in accordance with another embodiment of the disclosed technology; and 
         FIG. 19  is a partial isometric view of the power distribution unit shown in  FIG. 18  as viewed from the top and opposite the levers. 
     
    
    
     DETAILED DESCRIPTION 
     This description provides examples, and is not intended to unnecessarily limit the scope, applicability or configuration of the invention. Rather, the ensuing description will provide those skilled in the art with an enabling description for implementing embodiments of the invention. Various changes may be made in the function and arrangement of elements. Thus, various embodiments may omit, substitute, and/or add various procedures or components as appropriate. For instance, aspects and elements described with respect to certain embodiments may be combined in various other embodiments. It should also be appreciated that the following systems, devices, and components may individually or collectively be components of a larger system, wherein other procedures may take precedence over or otherwise modify their application. 
       FIG. 1  is an illustration of a representative PDU  100  of an embodiment that includes various features of the present disclosure. The PDU  100  includes a PDU housing  102  configured to receive a power input which may be connected to an external power source. The PDU  100  according to this embodiment includes housing  102  that is vertically mountable in an equipment rack, although it will be understood that other form factors may be used, such as a horizontally mountable housing. A plurality of locking combination outlet modules  120  may be located at least partially within the housing  102  through openings  108  in a front face  110  of the housing  102 . The outlet modules  120  will be described in more detail below. The PDU  100  of  FIG. 1  can include a suitable number of circuit protection devices, such as circuit breakers  112 , that provide over-current protection for one or more associated outlet modules  120 . The PDU  100  can also include a communications module  114  that may be coupleable with one or more of a local computer, local computer network, and/or remote computer network. A display portion  116  may be used to provide a local display of information related to current operating parameters of the PDU  100 , such as the quantity of current being provided by the input and/or flowing through one or more of the outlets, or the power or energy consumed by one or more outlets of the PDU, to name a few. 
     As show in  FIG. 2 , each locking combination outlet module  120  can include a module housing  122  and multiple outlets  124  and  126  positioned in the housing  122 . The outlet module  120  may be inserted into a corresponding PDU housing opening  108  and retained therein by multiple retainers  128 . In some embodiments, there are two retainers  128  on each end of the housing  122 . The housing  122  can include a flange portion  123  extending at least partially around the perimeter of the housing  122  and positioned against the front face  110  of the PDU housing  102 . 
     In some embodiments, the module can include various combinations of C13, C19, combination outlets and/or other suitable outlet types. The modules can include any suitable number of outlets arranged in any suitable orientation, pattern, and/or array. For example, outlet module  120  can include three C13 outlets  124  and three combination outlets  126 , as shown. Combination outlets  126  are described more fully below with respect to  FIGS. 6A and 6B . A latch lever  130  is pivotably coupled to the housing  122  adjacent each one of the outlets  124  and  126 . Each latch lever  130  is moveable (e.g., pivotable) between a latch position (e.g., first position) (as shown in  FIG. 2 ) whereby a mating plug (not shown) can be inserted into the module  120  and subsequently retained therein, and an unlatch position (e.g., second position) whereby the mating plug can be removed from the module  120 . 
     In some embodiments, the outlets  124  and  126  can be electrically ganged together via circuit conductors  132  and  134 , for example. The PDU housing  102  can include a conductive ground tab  136  positioned to tie the ground circuit conductor  132  to chassis ground. Referring to  FIG. 3 , the outlets can each include a ground terminal  138 ( a ) ganged together via the ground circuit conductor  132 . The ground circuit conductor  132  may in turn be coupled to the ground tab  136  ( FIG. 2 ) with an angle bracket  144  and cooperating fasteners  146  (e.g., a nut and bolt). The outlets can each include a first power terminal  138 ( b ) ganged together via power circuit conductor  134 . In some embodiments, the ground terminals  138 ( a ) and the first power terminals  138 ( b ) can have a common construction including a connection aperture  140  through which the circuit conductors  132  and  134  extend. Each outlet can also include a second power terminal  142 . In some embodiments, only some of the terminals are electrically ganged together and in other embodiments all of the terminals may be left unganged. 
     The power circuit conductor  134  and each second power terminal  142  can be coupled to a controller (not shown) to individually control and monitor each outlet. The terminals  138  can be soldered to the conductors  132 / 134 , for example. In some embodiments, the conductors  132 / 134  and the electrical terminals  138  and  142  can be constructed from suitable electrically conductive materials such as tin, gold, silver, copper, phosphor bronze, and the like. Multiple materials can be used in combination. In one embodiment, the terminals can comprise copper alloy with a tin plating. Ganged outlet connection schemas are also described in commonly owned U.S. patent application Ser. No. 16/039,211, filed Jul. 18, 2018, the disclosure of which is hereby incorporated by reference in its entirety. 
     As shown in  FIG. 3 , each of the latch levers  130  can pivot about a common pivot shaft  148 . Thus, each latch lever  130  can be moved between a first position, wherein the latch lever  130  is capable of engaging a mating plug (not shown) and a second position, wherein the latch lever  130  is disengaged from the plug. In some embodiments, the pivot shaft  148  can be captured in the module housing  122  by the PDU housing  102 , as the pivot shaft  148  is aligned with the front face  110  (see  FIG. 2 ). In some embodiments, each latch lever  130  can have its own separate pivot shaft or pin. 
     Turning to  FIG. 4 , in some embodiments, the outlet module  120  can include light pipes  150  extending from a printed circuit board (not shown) and into a corresponding opening  152  in the module housing  122 . The light pipes  150  can comprise a light conducting plastic material to transfer light from a light emitting diode (not shown) on the printed circuit board to the top of the module adjacent each outlet ( FIG. 5 ). This arrangement can be used to indicate the status of the outlets (e.g., on or off). 
     In some embodiments, suitable fasteners, such as screws  154 , can extend through the bottom of the module housing  122  to secure the outlets  124  and  126  to the outlet module  120 . Referring to  FIG. 5 , each outlet  124  and  126  can comprise a separate outlet core  125  and  127 , respectively, fastened to a base surface  160  of the module housing  122 . Each outlet  124 / 126  also includes terminals  138  and  142  as shown. One of the outlet cores  127  is removed to illustrate the positions of the terminals  138  and  142  therein. An outlet core is understood to be as described in commonly owned U.S. Pat. Nos. 9,614,335 and 9,627,828, filed Apr. 9, 2015 and Nov. 13, 2014, respectively, the disclosures of which are incorporated herein by reference in their entireties. 
     In some embodiments, the module housing  122  includes the base surface  160  and a sidewall  162  extending therefrom to at least partially surround an interior region  164 . The base surface  160  and the sidewall  162  can comprise an integrally molded unitary body (e.g., injection molded plastic). In some embodiments, the outlet cores  125  and  127  can also be integrally molded with the base surface  160  and the sidewall  162 . 
     Each latch lever  130  is pivotably coupled to the sidewall  162  outside the interior region  164 , wherein each latch lever  130  is positioned adjacent a corresponding one of the outlet cores  125 / 127 . Each latch lever  130  includes a tooth portion  180  extending through a corresponding aperture  166  and into the interior region  164  to engage a mating plug (not shown) when the latch lever  130  is in the latch position as shown in  FIG. 5 . In some embodiments, the sidewall  162  can include ribs  165  positioned opposite the latch levers  130  to account for variability in the dimensions of a mating plug to help ensure that the latch lever tooth  180  remains engaged with the plug. 
     As shown in  FIGS. 6A and 6B , the combination outlet  126  incorporates slots  174  and electrical contacts  138 / 142  for a first connector type (e.g., standard C13/C14) as well as a second connector type (e.g., standard C19/C20). In other words, the outlet core  127  has the envelope of a C13 outlet, but can accept both C14 and C20 plugs. The standard connector types referred to herein (e.g., C13, C14, C19, and C20) all refer to industry standard connectors defined in International Electro technical Commission (IEC) standard publication IEC60320 as of the filing date of the present application. 
     Although the embodiments are shown and described with respect to C13/C14 and C19/C20 connectors, other connector combinations could be used. Other suitable connector types might include, for example and without limitation, industry standard connectors, such as IEC C2, C4, C6, C8, C10, C12, C16, C16A, C18, C22, C24 or NEMA 5-10R, 5-15R, 5-20R, 6-20R, 6-30R, 6-50R, L15-20R, L15-30R, L21-20R, L21-30R. In various embodiments, the connectors could include connectors defined in the IEC standard as of the filing date of the present application. 
     The combination outlet core  127  has an input side  170  and an output side  172  with three apertures  174  extending therebetween. The outlet core  127  has a core outer surface  176  configured to mate with a first connector type. For example, in the depicted embodiment the core outer surface  176  is configured as a C13 outlet to mate with a C14 plug. The apertures  174  are each configured to receive mating terminals corresponding to both the first connector type (e.g., C14) and the second connector type (e.g., C20). In this embodiment, the apertures  174  comprise intersecting cross-wise slots or T-shaped apertures, for example. Accordingly, the apertures  174  can accept the terminals of a C20 plug and the perpendicularly oriented terminals of a C14 plug. In some embodiments, the combination outlet core  127  can comprise injection molded plastic, for example. 
     The input side  170  of the combination outlet core  127  can include a pair of bosses  178  and corresponding mounting holes  179 . The bosses  178  can be used to locate the combination outlet core  127  on the base surface  160  ( FIG. 5 ). Screws  154  ( FIG. 5 ) can be threaded into the mounting holes  179  in order to attach the outlet core  127  to the base surface  160 . Other mounting arrangements are possible. For example, the outlet core  127  can be adhered to the base surface  160  with a suitable adhesive. In still other embodiments, the outlet core  127  can be captured on the base surface  160  by the electrical terminals  138 / 142 . In some embodiments, the core outer surface  176  can include a plurality of ribs  177  to help retain a mating plug on the outlet  126 . The ribs  177  can help account for variability in the dimensions of mating plugs and reduce side-to-side movement between a core and mating plug, which helps ensure that the latch lever tooth  180  remains engaged with the mating plug. Combination outlets are also described in commonly owned U.S. Pat. No. 10,249,998, filed Jul. 13, 2017, and U.S. Pat. No. 10,498,096, filed Apr. 1, 2019, the disclosures of which are hereby incorporated by reference in their entireties. In some embodiments, the C13 outlet  124  can have essentially the same construction as that described above with respect to the combination outlet  126 , with the exception that the C13 outlet core  125  does not have T-shaped apertures (see e.g.,  FIG. 5 ). 
     As shown in  FIG. 7 , the C13 outlets  124  can be spaced apart from each other a first distance D 1  and the combination outlets  126  can be spaced apart a second distance D 2 . The combination outlets  126  can also have more clearance between the sidewall  162  and the outlets than the C13 outlets  124  in order to accommodate a C20 plug, which is larger than a C14 plug. In some embodiments, D 1  is approximately 21.10 mm and D 2  is approximately 26.55 mm. The outlets  124  and  126  have an unobstructed space S between adjacent outlet cores, which is in contrast to conventional outlet arrangements. Conventional arrangements have a wall extending between each outlet. The present technology does not have a wall between adjacent outlets thereby allowing the outlets to be spaced closer together than they could be with a wall between them. High density outlet designs are further described in commonly owned U.S. Pat. Nos. 9,614,335 and 9,627,828, previously incorporated herein by reference. 
     As shown in  FIG. 8 , the outlet module  120  can include multiple resilient members, such as coil compression spring  182 , each positioned between the sidewall  162  and a corresponding one of the multiple latch levers  130 . Although a compression spring is described herein, other suitable resilient member arrangements can be used, such as coil tension springs, torsion springs, and rubber members, to name a few. The compression spring  182  is positioned with respect to the pivot shaft  148  to bias the corresponding latch lever tooth portion  180  toward the latch position (as shown in  FIG. 8 ). To temporarily move the latch lever  130  to an unlatch position, a user can push and hold the latch lever  130  toward, for example, the outlet  126 , as indicated by arrow P, thereby pivoting the tooth portion  180  away from the outlet  126 , such that the tooth portion  180  is retracted from a mating plug (not shown). 
     As shown in  FIG. 9 , the latch levers  130  can each comprise a release tab  184  located opposite the tooth portion  180 . A pivot bore  186  is positioned between the release tab  184  and the tooth portion  180 . A spring pocket  188 , is positioned between the release tab  184  and the pivot bore  186 , whereby the compression spring  182  ( FIG. 8 ) normally biases the tooth portion  180  toward a corresponding outlet. In some embodiments, the spring pocket  188  has an open side, as shown, to facilitate assembly, whereas in other embodiments, the spring pocket  188  can have closed sides. When a plug is inserted into the interior region  164  ( FIG. 5 ) and onto an outlet, the plug exerts a force F on the tooth portion  180  which in turn pivots the latch lever  130  as indicated by arrow R to allow the plug to move past the tooth portion  180 . Once the plug is fully inserted, the tooth portion  180  is urged by the spring  182  to engage a surface on the side of the plug, for example, thereby locking the plug in the outlet module  120 . In some embodiments, the tooth portion  180  has a sharp edge  181  configured to bite into the side of a plastic plug. In some embodiments the tooth portion  180  can engage an opening or recess (not shown) on the side of the plug. 
       FIG. 10  illustrates a locking combination outlet module  120  with representative power cords connected thereto. One of the power cords includes an IEC C20 plug  190  and the other cord includes an IEC C14 plug  192 . As shown in  FIGS. 11 and 12 , the latch levers  130  are arranged in the outlet module to retain both types of plugs (e.g., C14 and C20). In a representative embodiment as shown in  FIG. 11 , the center of pivot shaft  148  is positioned such that the tooth  180  can engage both types of plugs. In some embodiments, the center of the pivot shaft  148  can be located approximately 6.5 mm from the top of the module and approximately 6.3 mm from an inside surface of the module. Thus, when a C20 plug  190  is inserted into the module, the angle A between the top surface of the module and a line extending through the center of shaft  148  and the edge of tooth  180  is approximately 50.9 degrees. Referring to  FIG. 12 , when a C14 plug  192  is inserted into the module, the angle A between the top surface of the module and the line extending through the center of shaft  148  and the edge of tooth  180  is approximately 29.7 degrees. 
       FIG. 13  is a cross-sectional diagram of a latch lever arrangement according to another representative embodiment. In the depicted embodiment, the module housing  222  includes a base surface  260  and a sidewall  262  extending therefrom to at least partially surround an interior region  264 . The base surface  260  and the sidewall  262  can comprise an integrally molded unitary body (e.g., injection molded plastic). In some embodiments, an outlet core  225  can also be integrally molded with the base surface  260  and the sidewall  262 . In other embodiments, the outlet core  225  is a separate element suitably attached to the base surface  260 . 
     Each latch lever  230  is pivotably coupled to the sidewall  262  with a pivot shaft  248  outside the interior region  264 , wherein each latch lever  230  is positioned adjacent a corresponding outlet core  225 . Each latch lever  230  includes a tooth portion  280  extending into the interior region  264  to engage a mating plug, such as IEC C20 plug  290 , when the latch lever  230  is in a latch position as shown. The latch lever  230  includes a pawl  232  positioned to engage one of multiple latch positions each corresponding to a ratchet tooth. In this case, there are two ratchet teeth  234  and  236  formed in the housing  222 . Tooth  234  corresponds to a first latch position for engaging a C20 plug and tooth  236  corresponds to a second latch position for engaging a C14 plug. In some embodiments, the pawl  232  can comprise a resilient material, such as plastic, in order to allow the pawl  232  to deform as it moves over each tooth. 
       FIG. 14  illustrates a locking combination outlet module  320  according to another representative embodiment. The locking combination outlet module  320  can include a front panel  322  which can comprise part of a PDU housing in which the module  320  is housed. In some embodiments, the module can include various combinations of C13, C19, combination outlets and/or other suitable outlet types. The module can include any suitable number of outlets arranged in any suitable orientation, pattern, and/or array. As shown in the depicted embodiment, outlet module  320  can include 27 combination outlets  326 . The combination outlets  326  are substantially the same as combination outlets  126  and are thus described more fully above with respect to  FIGS. 6A and 6B . 
     The outlets  326  can be spaced apart to accommodate different plug types. For example, the first and third sets of nine outlets  326  are spaced apart to accommodate C14 plugs while the second (i.e., center) set of outlets are spaced further apart to accommodate both C14 and C20 plugs. See  FIG. 7  for suitable outlet spacings, for example. In some embodiments, each set of outlets  326  is positioned in a corresponding opening  307 - 309  in the front panel  322 . 
     In some embodiments, the module  320  includes a base surface  360  from which the outlet cores  326  extend. The base surface  360  can be the surface of a first printed circuit board (PCB), such as an outlet board  362  ( FIG. 15 ). As with the foregoing embodiments described herein, the outlets  326  have an unobstructed space between adjacent outlet cores, as shown. 
     A latch lever  330  is positioned adjacent each one of the outlets  326 . Each latch lever  330  is moveable (e.g., pivotable) between a latch position (e.g., first position) (as shown in  FIG. 14 ) whereby a mating plug (e.g., plugs  190  and  192  in  FIG. 10 ) can be inserted into the module  320  and subsequently retained therein, and an unlatch position (e.g., second position) whereby the mating plug can be removed from the module  320 . 
     Referring to  FIG. 15 , in some embodiments, the outlet module  320  can include light pipes  350  extending from a second PCB, such as a relay board  364  and into a corresponding opening  352  in the front panel  322 . The light pipes  350  can comprise a light conducting plastic material to transfer light from a light emitting diode (not shown) on the relay board  364  to the top of the module adjacent each outlet. This arrangement can be used to indicate the status of the outlets (e.g., on or off). 
     Each outlet core  326  can be mounted to the outlet board  362  in a similar manner to that described above with respect to  FIG. 5 . Accordingly, the outlet cores  326  can be mounted using suitable fasteners, such as screws  154  extending through the outlet board  362 . Each outlet  326  also includes terminals similar to terminals  138  and  142 , as shown and described with respect to  FIG. 5 . 
     The front panel  322  can include a face portion  370  with first and second side panel portions  372  and  374 , respectively. The first side panel  372  can include multiple short and long fingers  376  and  378 , respectively, positioned to support and capture a side of the outlet board  362 . Each finger  376  and  378  can include a inwardly extending support tab  380  positioned to confront a corresponding top or bottom of the outlet board  362 . The second side panel  374  can include multiple inwardly extending mounting tabs  382  having threaded inserts, for example, to receive an attachment screw (not visible) for securing the outlet board  362  to the front panel  322 . 
     As shown in  FIG. 16 , the relay board  364  can be secured to the outlet board  362  with suitable mounting hardware, such as spacers or standoffs  384 . In some embodiments, the latch levers  330  can be mounted in a lever bracket  390  which is fastened to the front panel  322  with suitable fasteners (not shown) extending through mounting holes  386  formed through the second side panel  374 . With further reference to  FIG. 17 , each lever bracket  390  can support three latch levers  330 ; however, the bracket can be configured to support more or fewer latch levers  330 . In some embodiments, the lever bracket  390  can comprise molded plastic, for example. The bracket  390  can include threaded inserts  392  to facilitate mounting the assembly to the front panel  322 . 
     The latch levers  330  are substantially the same as latch levers  130  and thus their construction is described more fully above with respect to  FIGS. 8 and 9 . As with the previous embodiments, each latch lever  330  can pivot about a common shaft or pivot about a separate shaft for each lever. Furthermore, each latch lever  330  can be urged toward the latched position with a corresponding resilient member, such as a coil compression spring, positioned between the latch lever  330  and the lever bracket  390  in an arrangement similar to that shown in  FIG. 8 , for example. 
       FIG. 18  illustrates a power distribution unit  400  incorporating locking combination outlets in accordance with embodiments of the disclosed technology. The PDU  400  can include a housing  402  having a front panel  404 . In some embodiments, the front panel  404  comprises a single panel extending substantially the entire length of the PDU  400 . In some embodiments, the PDU can include various combinations of C13, C19, combination outlets and/or other suitable outlet types. The PDU can include any suitable number of outlets arranged in any suitable orientation, pattern, and/or array. As shown in the depicted embodiment, PDU  400  can include 48 combination outlets  406 . The combination outlets  406  are substantially the same as combination outlets  126  and are thus described more fully above with respect to  FIGS. 6A and 6B . 
     The outlets  406  can be spaced apart to accommodate different plug types. For example, the outlets  406  associated with apertures  408 ,  412 ,  414 , and  418  can be spaced apart to accommodate C14 plugs while the outlets associated with apertures  410  and  416  can be spaced further apart to accommodate both C14 and C20 plugs. See  FIG. 7  for suitable outlet spacings, for example. 
     In some embodiments, the PDU  400  includes a base surface  420  from which the outlet cores  406  extend. The base surface  420  can be the surface of a PCB, such as an outlet board  422  ( FIG. 19 ). As with the foregoing embodiments described herein, the outlets  406  have an unobstructed space between adjacent outlet cores, as shown. Each outlet core  406  can be mounted to the outlet board  422  in a similar manner to that described above with respect to  FIG. 5 . Accordingly, the outlet cores  406  can be mounted using suitable fasteners. Each outlet  406  also includes terminals similar to terminals  138  and  142 , as shown and described with respect to  FIG. 5   
     With reference to  FIG. 19 , a latch lever  430  is positioned adjacent each one of the outlets  406 . Each latch lever  430  is moveable (e.g., pivotable) between a latch position (e.g., first position) whereby a mating plug (e.g., plugs  190  and  192  in  FIG. 10 ) can be inserted into the PDU  400  and subsequently retained therein, and an unlatch position (e.g., second position) whereby the mating plug can be removed from the PDU  400 . 
     The latch levers  430  are substantially the same as latch levers  130  and thus their construction is described more fully above with respect to  FIGS. 8 and 9 . In some embodiments, the latch levers  430  can be mounted in the PDU  400  with an arrangement similar to that described above with respect to  FIG. 16 . 
     The front panel  404  can include a face portion  470  with first and second side panel portions  472  and  474 , respectively. The first and second side panels  472  and  474  can each include multiple hooks  476  positioned to engage corresponding notches  478  along the edges of PCB  422 , thereby retaining the PCB  422  relative to the front panel  404 . 
     It should be noted that the systems and devices discussed above are intended merely to be examples. It must be stressed that various embodiments may omit, substitute, or add various procedures or components as appropriate. For instance, it should be appreciated that, in alternative embodiments, features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. Also, it should be emphasized that technology evolves and, thus, many of the elements are exemplary in nature and should not be interpreted to limit the scope of the invention. It will be noted that various advantages described herein are not exhaustive or exclusive, and numerous different advantages and efficiencies may be achieved, as will be recognized by one of skill in the art. 
     Specific details are given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, well-known circuits, structures, and techniques have been shown without unnecessary detail in order to avoid obscuring the embodiments. 
     Having described several embodiments, it will be recognized by those of skill in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the invention. For example, the above elements may merely be a component of a larger system, wherein other rules may take precedence over or otherwise modify the application of the invention. Also, a number of steps may be undertaken before, during, or after the above elements are considered. Accordingly, the above description should not be taken as limiting the scope of the invention.