Abstract:
The disclosed concept pertains generally to electrical switching apparatus, such as circuit breakers, and more particularly, to enclosures for electrical switching apparatus and the components of the enclosures, such as latching doors and latching mechanisms.

Description:
BACKGROUND 
       [0001]    1. Field 
         [0002]    The disclosed concept relates generally to electrical switching apparatus and, more particularly, to electrical switching assemblies, such as for example, circuit breakers. The disclosed concept also relates to electrical switching enclosures and components associated therewith, such as, for example, latching doors and latching mechanisms. 
         [0003]    2. Background Information 
         [0004]    Electrical switching assemblies are generally well known in the art and include, for example, circuit switching devices and circuit interrupters, such as circuit breakers, contactors, motor starters, motor controllers and other load controllers. 
         [0005]    Circuit breakers are used for protecting electrical circuitry from damage due to an over current condition, such as an overload condition or a relatively high level short circuit or fault condition. Molded case circuit breakers, for example, include at least one pair of separable contacts which are operated either manually by way of a handle disposed on the outside of the case or automatically by way of an internal trip unit in response to an over current condition. In the automatic mode of operation, an electronic trip unit, for example, controls an operating mechanism that opens the separable contacts. In the manual mode of operation, the handle cooperates with the operating mechanism in order to open the separable contacts. Circuit breakers have at least one line terminal for connection to a power source and at least one load terminal for connection to a load, such as a motor. The separable contacts of the circuit breakers are internally connected to the line and load terminals. 
         [0006]    Typically, electrical switching assemblies, e.g., circuit breakers, are contained within enclosures. The enclosures are effective to protect the electrical switching assemblies from exposure to environmental conditions. The enclosures typically include at least one circuit breaker and internal components positioned therein. 
         [0007]    The design and structure of the enclosures can vary. In general, the enclosures are typically sized such that they are large enough to house the circuit breakers and related equipment and components. Enclosures known in the art include rectangular members having a base with sides which form a cavity wherein the circuit breakers and related equipment and components are positioned. It is understood that the shape of the enclosure is not critical and it is contemplated that various shapes are suitable. The enclosures also include a door connected to at least one of the sides of the enclosures. The door is structured to cover the open surface of the cavity, as well as to provide access to the cavity. For example, the door may connected to one side by hinges and may include a latch for opening and closing the door. It is typical for the door to be pulled open and therefore, open outwardly. 
         [0008]    Further, existing arc-resistant latching mechanism designs can be bulky and require a relatively large amount of space to secure all associated components while maintaining the ability to install and remove withdrawable electrical devices, e.g., circuit breakers, fuses, and transformers, without interference with latching components. 
         [0009]    Due to space limitation being a prevalent constraint associated with switchgear applications, there is an increasing need to design and develop switchgear assemblies that are compact and continue to meet all existing functionality requirements. 
         [0010]    Accordingly, there is room for improvement in known electrical switching assembly, such as circuit breaker, enclosures. It is desired that an enclosure, access door and arc resistant latching mechanism be designed and developed to enclose or house the circuit breaker and associated components, to be capable of easy access in small spaces, of withstanding internal pressure waves and other destructive forces that can be produced under fault conditions, and of being cost effective to construct and install. 
       SUMMARY 
       [0011]    These needs and others are met by embodiments of the disclosed concept. 
         [0012]    In one aspect, the disclosed concept provides a latching apparatus for an enclosure of an electrical switching assembly. The enclosure includes a housing having an outer surface structured to form a cavity therein and, an access panel connected to the housing and structured to open to provide access to the cavity of the housing. The latching apparatus includes a series of stationary c-shaped channels mounted to and extending along at least a portion of a perimeter of the housing, each of the series of stationary c-shaped channels has a series of stationary pins inserted and extending through both legs of the c-shaped channel; a movable latch rod connected to and extending along at least a portion of a perimeter of the access panel, the latch rod structured to be positioned within the stationary c-shaped channel when the access panel is in its closed position in relation to the housing, and the latch rod having formed therein a series of hook-shaped profiles structured to mechanically engage the stationary pins; and a handle connected to the access panel and structured to mechanically engage the latch rod and translate the latch rod a distance along the perimeter of the access panel such that the hook-shaped profiles mechanically engage the stationary pins and latch the access panel with the housing. 
         [0013]    The electrical switching assembly can be a circuit breaker. 
         [0014]    The handle can include a rack-and-pinion mechanism. 
         [0015]    The stationary pins can be selected from clevis-style pins, bolts and other similar components. 
         [0016]    In certain embodiments, the series of stationary c-shaped channels is mounted to the housing using a series of a combination of nut and bolt, e.g., countersunk bolt. The channel can be formed of steel or other comparable material. 
         [0017]    In certain embodiments, the latch rod is mounted to the access panel by forming a tab along at least a portion of the perimeter of an interior face of the access panel and attaching the latch rod to the tab using a series of a combination of nut and screw. The nut can be a lock nut, e.g., nylon lock nut, and the screw can be a machine screw. 
         [0018]    In another aspect, the disclosed concept provides an enclosure for an electrical switching assembly. The enclosure includes a housing having an outer surface structured to form a cavity therein; an access panel connected to the housing and structured to open to provide access to the cavity of the housing; and a latching apparatus. The latching apparatus includes a series of stationary c-shaped channels mounted to and extending along at least a portion of a perimeter of the housing, the channel having a series of stationary pins inserted and extending through both legs of the c-shaped channel; a movable latch rod connected to and extending along at least a portion of a perimeter of the access panel, the latch rod structured to be positioned within the stationary c-shaped channel when the access panel is in its closed position in relation to the housing, and the latch rod having formed therein a series of hook-shaped profiles structured to mechanically engage the stationary pins; and a handle connected to the access panel and structured to mechanically engage the latch rod and translate the latch rod a distance along the perimeter of the access panel such that the hook-shaped profiles mechanically engage the stationary pins and latch the access panel with the housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which: 
           [0020]      FIG. 1  is a schematic of an enclosure having a latching mechanism mounted thereto, in accordance with certain embodiments of the disclosed concept; 
           [0021]      FIG. 2  is a detail view of the latching mechanism shown in  FIG. 1 , in accordance with certain embodiments of the disclosed concept; 
           [0022]      FIG. 3  is a detail view of a corner mechanism shown in  FIG. 1 , in accordance with certain embodiments of the disclosed concept; 
           [0023]      FIG. 4  is a detail view of a latch handle shown in  FIG. 1 , in accordance with certain embodiments of the disclosed concept; 
           [0024]      FIG. 5  is a side view schematic of the latching mechanism when in an open or de-actuated position, in accordance with certain embodiments of the disclosed concept; 
           [0025]      FIG. 6  is a side view schematic of the latching mechanism when in a closed or actuated position, in accordance with certain embodiments of the disclosed concept; 
           [0026]      FIG. 7  is a schematic showing a movable latch rod positioned within a stationary channel, in accordance with certain embodiments of the disclosed concept; 
           [0027]      FIG. 8  is a detail view of the movable latch rod shown in  FIG. 7  in the absence of the stationary channel, in accordance with certain embodiments of the disclosed concept; and 
           [0028]      FIG. 9  is a front view schematic showing the latching mechanism, in accordance with certain embodiments of the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    Direction phrases used herein, such as, for example and without limitation, top, bottom, left, right, upper, lower, front, back and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein. 
         [0030]    As employed herein, the statement that two or more parts are “connected” or “coupled” together shall mean that the parts are joined together either directly or joined through one or more intermediate parts. Further, as employed herein, the statement that two or more parts are “attached” shall mean that the parts are joined together directly. 
         [0031]    The disclosed concept is described in association with electrical switching apparatus or assemblies, such as circuit breakers, although it will become apparent that the disclosed concept could also be applied to other types of electrical switching apparatus, e.g., without limitation, other circuit switching devices and other circuit interrupters such as contactors, motor starters, motor controllers and other load controllers. The arc resistant latching door mechanism, which is described in accordance with the disclosed concept, is effective to provide mechanical strength needed to secure an external door of a switchgear enclosure when subjected to internal pressure waves and similar destructive forces that may be produced under fault conditions. The arc resistant latching door mechanism includes a latch rod, which is described in detail later herein, that provides proper compression and seal of a gasket material, which may be used in conjunction with the latching mechanism. 
         [0032]    Additionally, the arc resistant latching mechanism requires less space for installation than conventional latching mechanisms that are known in the art. 
         [0033]      FIG. 1  shows an enclosure  10  that includes a housing  20  and an access panel  30  that provides access to the interior of the housing  20 . The access panel  30  is attached to the housing  20  by frame components  22 , which are positioned on the perimeter of one side of the housing. The frame components  22  allow the access panel  30  to be opened and closed. The frame components  22  can be selected from a wide variety of fasteners that are known in the art and commercially available. Typically, the frame components  22  are selected from a variety of known, commercially available, hinged-type fasteners that allow the access panel  30  to be pulled outward in order to access the interior of the housing  20 . As shown in  FIG. 1 , along the perimeter on the three sides of the housing  20  and the access panel  30  (which do not include the frame components  22 ) is mounted a latching mechanism  115 . Although,  FIG. 1  shows the latching mechanism  115  mounted on three sides, it is contemplated that the latching mechanism  115  may be mounted along the perimeter on all four sides of the housing  20  and the access panel  30  (including the side having the frame components  22 ). The latching mechanism  115  can be mounted directly to the housing  20  and the access panel  30  or, alternatively, a plate can be mounted to or fabricated along the perimeter of the housing  20  and the access panel  30 , and the latching mechanism  115  can be attached to the plate. As shown in  FIG. 1 , the access panel  30  also includes a handle  50  mounted thereto. The handle  50  can be selected from various handles that are known in the art for this purpose and commercially available. Typically, the handle  50  is a rack-and-pinion-style handle, which can be turned in a clockwise or counterclockwise direction to open and close the access panel  30 . In addition, the handle  50  is operable upon turning to actuate or de-actuate the latching mechanism  115 . Although  FIG. 1  shows the handle  50 , it is contemplated that various mechanisms can be employed to open and close the access panel  30 , and to actuate or de-actuate the latching mechanism  115 . 
         [0034]    The latching mechanism  115  includes a series of stationary c-shaped formed channels  120  mounted to the perimeter of the housing  20  and a movable latch rod  135  connected to the perimeter of the access panel  30 . The stationary channels  120  can be formed from various materials known in the art including, but not limited to, steel. As shown in  FIG. 1 , the stationary channels  120  are mounted to the perimeter of three sides of the housing  20  and the latch rod  135  is connected to the perimeter of three sides of the access panel  30 . As previously described, the stationary channel  120  and the movable latch rod  135  can be directly mounted/connected to the housing  20  and access panel  30 , respectively. 
         [0035]    Alternatively, the channel  120  and the latch rod  135  can each be directly mounted/connected to a plate or tab, which can be formed along the perimeter of each of the housing  20  and the access panel  30 , respectively. Various mechanisms can be used to mount the channel  120  and the latch rod  135 . Suitable mechanisms include those known in the art for fastening one substrate to another substrate, such as, nut/bolt or nut/screw combinations (not shown). 
         [0036]    In certain embodiments, the series of channels  120  is mounted to the face of the housing  20  using nut/countersunk bolt combinations  155  (shown in  FIG. 9 ) and the latch rod  135  is mounted to a plate or tab, which is attached, e.g., welded, to an interior face of the access panel  30 , using lock nut/screw, e.g., nylon lock nut/machine screw, combinations  130  (shown in  FIG. 2 ). It is contemplated that a friction reducing material, such as, but not limited to, nylon washers, also can be positioned between the latch rod  135  and the plate or tab to reduce friction and promote a smoother action for movement of the latch rod  135 .  FIG. 2  shows the details of view A of the latching mechanism  115  as shown in  FIG. 1  including the series of c-shaped channels  120  and latch rod  135 . Each of the c-shaped channels  120  has stationary pins  125  inserted through both legs. The stationary pins  125  can include clevis-style pins, bolts or other similar components, which are known in the art. The latch rod  135  is mounted to the perimeter of the access panel  30  using a series of nut/screw combinations  130 . It is contemplated that the latch rod  135  can be mounted to the access panel  30  using various configurations. In certain embodiments, the latch rod  135  is guided by a full-length tab (not shown) which is attached, e.g., welded, to an interior face of the access panel  30 . The latch rod  135  can be secured to this tab by screws  160 , e.g., machine screws, and lock nuts  165 , e.g., nylon lock nuts. As previously described, a friction reducing material can also be positioned between the latch rod  135  and guide tab (not shown) to reduce friction and promote a smoother action. The latch rod  135  has formed therein a series of hook-shaped profiles  140 . The stationary pins  125  extend through the hook-shaped profiles  140  in the latch rod  135  to form latching catch points. When the access panel  30  is closed, the latch rod  135  is positioned within the series of c-shaped channels  120 .  FIG. 3  shows the details of view B of the latching mechanism  115  as shown in  FIG. 1 .  FIG. 3  shows the series of c-shaped channel  120   s,  pins  125 , nut/screw combinations  130 , latch rod  135  and hook-shaped profiles as shown in  FIG. 2 . In addition,  FIG. 3  shows a corner mechanism  170  mounted on a corner portion of the access panel  30 . The corner mechanism  170  can be a bracket or the like, which is known in the art and commercially available. The corner mechanism  170  is structured to allow the latch rod  135  to translate motion through 90 degrees. The channel  120  does not extend around the perimeter of the corners of the housing  20 . 
         [0037]    When the access panel  30  is closed, the latch rod  135  is positioned within the channel  120  and the handle  50  on the access panel  30  is turned in a particular direction, e.g., clockwise or counterclockwise, to actuate the latching mechanism  115 . Upon actuation, the latch rod  135  translates a distance around the perimeter of the access panel  30  and housing  20  causing the stationary pins  125  and the hook-shaped profiles  140  to be mechanically engaged. As previously described, the stationary pins  125  extend through the hook-shaped profiles  140  in the latch rod  135  to form latching catch points and to securely latch the access panel  30  to the housing  20 . To de-actuate the latching mechanism  115  and open the access panel  30 , the handle  50  is turned in the opposite direction and causes the latch rod  135  to translate in an opposite direction. As a result, the hook-shaped profiles  140  disengage the stationary pins  125  and allow the access panel  30  to be opened.  FIG. 4  shows the details of view C of the latching mechanism  115  as shown in  FIG. 1 .  FIG. 4  shows the door handle  50 , series of c-shaped channels  120 , stationary pins  125  and latch rod  135 . As shown, the series of c-shaped channels  120  is stationary and mounted to the perimeter of the housing  20 , and the latch rod  135  is mechanically engaged with the door handle  50  and the latch rod  135  is structured to translate in a direction along the perimeter of the access panel  30 /housing  20  upon turning of the handle  50 . 
         [0038]      FIG. 5  is a schematic showing the latching mechanism  115  including the channel  120 , stationary pins  125 , latch rod  135 , nut/screw combinations  130  and hook-shaped profiles  140 . In particular,  FIG. 5  shows the latching mechanism  115  in its open or de-actuated condition. 
         [0039]      FIG. 6  is a schematic showing the latching mechanism  115  including the series of c-shaped channels  120 , stationary pins  125 , latch rod  135 , nut/screw combinations  130  and hook-shaped profiles  140 . In particular,  FIG. 6  shows the latching mechanism  115  in its closed or actuated condition. As the latch rod  135  translates from the open position shown in  FIG. 5  to the closed position shown in  FIG. 6 , the hook-shaped profiles  140  are moved to mechanically engage the stationary pins  125  and to latch or lock the access panel  30  with the housing  20  (as shown in  FIG. 1 ). 
         [0040]      FIG. 7  is a schematic showing an isometric view of the latching mechanism  115  including the series of c-shaped channels  120 , stationary pins  125 , latch rod  135  and nut/screw combinations  130 . 
         [0041]      FIG. 8  is a schematic of the latching mechanism  115  in the absence of the series of c-shaped channels  120 . In  FIG. 8 , the latch rod  135  is attached to the access panel  30  using the nut/screw combinations  130 . In addition,  FIG. 8  shows the stationary pins  125  that extend through the hook-shaped profiles  140 . The stationary pins  125  are mechanically engaged within the hook-shaped profiles  140  (to latch or secure the access panel  30  to the housing  20  as shown in  FIG. 1 ). 
         [0042]      FIG. 9  is a front view schematic of the latching mechanism  115  showing the series of c-shaped channels  120 , stationary pins  125 , nut/screw combinations  130  and latch rod  135 . In addition,  FIG. 9  shows the nuts/countersunk bolts  155 , which attach the series of c-shaped channels  120  to the housing  20 . 
         [0043]    It is understood that the number of stationary pins  125 , nut/screw combinations, nut/bolt combinations and hook-shaped profiles can vary depending on, for example, the particular electrical switching assembly and enclosure. Further, it is contemplated that the enclosure may include a gasket used in combination with the latching mechanism  115 . The gasket is typically positioned between the access panel  30  and the housing  20 . The latch rod  135  may be mounted to the access panel  30  such that the nut/screw combinations  130  used to connect the latch rod  135  can also serve to compress and seal the gasket. 
         [0044]    While specific embodiments of the disclosed concept have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof