Abstract:
A caution and barrier system for danger of electrical arcing is disclosed. The caution and barrier system includes at least two elongate arms that attach to respective sides of a piece of equipment. The arms carry warning indicia. Some embodiments attach via traditional mounting hardware, while others mount magnetically to the equipment. The arms may also pivot and may comprise separate sections attached together by hinges. Yet other versions of the arms may be mounted on equipment using a multi-position magnetic mount. The caution and barrier system is particularly suitable for use with high voltage apparatus where electrical arcing is likely.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Patent Application No. 61/646,025, filed on May 11, 2012. That application is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    In general, the invention relates to electrical safety devices, and more particularly, to a caution and warning barrier system that is used to prevent personnel from entering areas in which electrical arcing is likely. 
         [0004]    2. Description of Related Art 
         [0005]    Electrical arcs result from the release of electrical energy through the air when high voltage bridges a gap between conductors. Electrical arcs can occur naturally, e.g., lightning, but they are also common with electrical machinery. These electrical discharges are highly unpredictable and vary in occurrence, energy, path, and duration. Electrical faults resulting in electrical arcs give off thermal radiation and bright, intense light that can cause burns to the body. High-voltage arcs can also produce a considerable pressure wave by rapidly heating the air and producing a blast that can send molten metal droplets from melted copper and aluminum components in electrical equipment great distances at extremely high velocities. In addition to direct personal injury from these hot metals, arc blasts can throw a worker against nearby objects, causing secondary injuries, such as blunt force trauma, cuts, and abrasions. The impulse sound wave near the unprotected ear can also result in temporary or permanent traumatic hearing loss. Electrical arcs can also cause non-contact flash burns without accompanying electric shock, in which case the person receiving the arc burn never actually contacts an energized electrical conductor. 
         [0006]    The hazards of non-contact electric arc flashes are present at most industrial workplaces and are an everyday occurrence. Due to the nature and attitudes of industrial work, may workers experience electrical arcs in varying degrees, but do not report them because they are not, or do not perceive themselves to be, injured. Non-contact arcing incidents can result from human error as well as from equipment malfunctions and accidents; however, arcs are not always predictable or traceable to a particular error, malfunction, or circumstance. Sometimes, they simply occur—which is what makes them so dangerous. 
         [0007]    Standards for protecting workers generally focus on technical skills, instrumentation, safe operating procedures, and personal protective equipment. Protective equipment, including clothing, is one way of preventing arc flash injury. Good equipment design, proper maintenance, and good training can also reduce the risk of injury. However, even with standards, protective equipment, and other conventional measures, arcing incidents still occur, and still take a toll. 
       SUMMARY OF THE INVENTION 
       [0008]    Aspects of the invention relate to caution and barrier systems for electrical arcing. The barrier systems may provide safe spaces and proper caution and warning information to workers in danger of encountering electrical arcing from pieces of equipment. 
         [0009]    One particular aspect of the invention relates to a caution and barrier system that includes a pair of elongate arms adapted to be attached to a piece of equipment with a fastening mechanism, and a removable front barrier. The arms may contain indicia in the form of warning messages, cautionary colors, or industry standard placards. The fastening mechanism may comprise a set of bolts, screws or other fasteners, along with appropriate plates and other hardware, that are intended to allow the arms to be secured to respective sides (or other faces) of the piece of equipment. Holes or openings may be made or provided in the piece of equipment for attachment of the arms. The fastening mechanism may also provide a pivoting mechanism, allowing the arms to rotate between defined vertical and horizontal positions, and stopping or locking mechanisms to prevent movement beyond those defined vertical and horizontal positions. The arms may be comprised of individual sections that are joined together with hinging mechanisms so that they may be folded to clear obstructions while in certain positions or while in motion between the vertical or horizontal positions. The removable front barrier may take different forms and may attach to the front of the elongate arms utilizing conventional releasable fasteners. 
         [0010]    Another aspect of the invention relates to a caution and barrier system for electrical arcing. This system also includes a pair of elongate arms adapted to be attached to a piece of equipment with a fastening mechanism, and a removable front barrier. However, in embodiments according to this aspect of the invention, the fastening mechanism attaches to a ferromagnetic piece of equipment without modifying it. More particularly, the fastening mechanism may comprise a magnetic attachment system in which one or more magnetic fasteners are used to attach each arm to a side or face of the piece of equipment. Other aspects of the invention may utilize fastening mechanisms including suction cups or adhesives. 
         [0011]    Yet another aspect of the invention relates to a stand that is adapted to support appropriate barriers with warning indicia without any contact with particular equipment. 
         [0012]    A further embodiment of the invention relates to a caution and warning system with a “universal” magnetic mount. A pair of mounts attach magnetically to the sides of a piece of equipment. The mounts have guides that define a channel sized to support a guard arm. The guard arm is retained in the mount with a pin, and is positionable either parallel to the mount or perpendicular to it. 
         [0013]    Other aspects, features, and advantages of the invention will be set forth in the description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0014]    The invention will be described with respect to the following pictures and drawing figures, in which like numerals represent like elements throughout the drawings, and in which: 
           [0015]      FIG. 1  is a perspective view of a caution and barrier system for danger of electrical arcing, shown attached to a cabinet with pivoting arm components in a horizontal position; 
           [0016]      FIG. 2  is a perspective view of the caution and barrier system of  FIG. 1  with arm components pivoted into a vertical position; 
           [0017]      FIGS. 3A-3D  are side elevational, top plan, perspective, and end elevational views, respectively, of one of the arms of  FIG. 1  in isolation; 
           [0018]      FIG. 4  is a perspective view of another embodiment of the invention with hinged and foldable arm components, shown in the vertical position; 
           [0019]      FIGS. 5A-5D  are side elevational, top plan, perspective, and end elevational views, respectively, of one of the arms of  FIG. 4  in isolation; 
           [0020]      FIG. 6  is a perspective view of yet another embodiment of a caution and barrier system with magnetically fastened and detachable arm components, shown in the horizontal position; 
           [0021]      FIGS. 7A-B  are side elevational and perspective views, respectively, of one of the arms of  FIG. 6  in isolation; and 
           [0022]      FIG. 8  is a perspective view of the caution and barrier system in a freestanding embodiment; 
           [0023]      FIG. 9  is a perspective view of a caution and barrier system according to yet another embodiment of the invention, illustrating a warning arm mounted in a universal mount in a first position; 
           [0024]      FIG. 10  is a perspective view of one side of the cabinet shown in  FIG. 9 , illustrating the warning arm mounted in a second position; and 
           [0025]      FIG. 11  is a cross-sectional view taken through Line  11 - 11  of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION 
       [0026]      FIG. 1  is a perspective view of a caution and barrier system for danger of electrical arcing, generally indicated at  100 , according to one embodiment of the invention. The system  100  may be attached to a wide array of equipment, and provides both a visual warning of arcing danger and a physical barrier to prevent users from coming close enough to a piece of equipment to experience an arc flash. (For purposes of this description, the phrases “electrical arc,” “arc flash,” and “arc fault” may be taken to be essentially synonymous.) 
         [0027]    As shown in  FIG. 1 , a pair of guard arms  102  is attached to a cabinet  101  and extends from it. Each guard arm  102  contains warning indicia  120  which may for example be engraved, painted or adhered to it (e.g., in the form of a sticker). In the illustrated embodiment, the color of each guard arm  102  may act as one warning indication  120 , and separate stickers, plates, or other types of indicia  118  may be fixed at particular positions to provide additional warning indications. For example, each guard arm  102  may be red, orange, or another common warning color. Any additional stickers, plates, or placards  118  may conform to regulatory requirements or standards in describing the nature of the danger and required precautions and may use standard graphical symbols or words. 
         [0028]    The guard arms  102  are mirror images of each other, and each one includes similar components. They may be made of various non-conductive materials such as polymers, rubbers, or natural materials. Essentially any material may be used to make the guard arms  102 ; however, non-conductive materials should generally be used. 
         [0029]    A front detachable barrier  150  may be used to close the space between the front ends of the guard arms  102 . The barrier  150  may be a rope, chain, or plank of a non-conductive material. In the illustration of  FIG. 1 , the front detachable barrier  150  comprises a plastic chain that attaches to the front tips of the guard arms  102  using magnetically attractive material  140  attracted to magnetic coupling plates  116  attached to the front tips of the guard arms  120 . In other embodiments, the front detachable barrier  150  may be attached using eyebolts, hooks, snaps, or other conventional releasable fasteners. Whatever form it takes, the detachable barrier  150  is most advantageously constructed and adapted to be detached and moved aside to allow access to the cabinet  101  when necessary. 
         [0030]      FIG. 2  is a perspective view of the caution and barrier system  100  as described above, but with the front detachable barrier  150  removed and guard arms  102  in a vertical position. The guard arms  102  rotate about pivot posts  110  and sit on resting posts  112  in the horizontal position. Locking tabs  114  are provided to secure the guard arms  102  in the vertical position; they remain in the guard arms  102  and can be pushed into an opening (not shown in  FIG. 2 ) to lock the guard arms  102  upright in the vertical position. The vertical position illustrated in  FIG. 2  allows for access to a piece of equipment or the cabinet  101  itself. 
         [0031]      FIG. 3A  is a side elevational view detailing a guard arm  102  of the caution and barrier system  100  in isolation. The guard arms  102  may be of any suitable length, depending on how much space is required in order to ensure worker safety and equipment integrity, which will vary with the type of equipment and other factors. Safe distances for arc flash hazards can be calculated using conventional methods, such as the IEEE 1584 Guide for Performing Arc Flash Hazard Calculations (Institute of Electrical and Electronics Engineers, New York, N.Y., USA, 2002). For example, in the embodiment depicted in  FIG. 3A , the guard arms  102  may be about 60 inches long (a safe distance) by about 4 inches high (a suitable height for the indicia  120  and the additional indicia plate  118 ). The indicia plate  118  of the illustrated embodiment is set about 4 inches from the tip of the guard arm  102  and sets the beginning of the guard arm indicia at about 12 inches from the beginning of the guard arm  102 . In the illustrated embodiment, placement indicia  119  marks the point at which the guard arm  102  should be aligned with the forward edge of the cabinet  101 , in order to ensure that a sufficient length of the arms  102  extends beyond the cabinet  101 . 
         [0032]    The magnetic coupling  116  may be attached to the front end of the guard arm  102  using an assortment of fasteners such as screws, bolts, rivets, posts, or adhesives. In the illustrated embodiment, the magnetic coupling  116  is attached utilizing two post-like fasteners. Alternatively, eyebolts, hooks, or other means of securing the front detachable barrier  150  may be attached in substantially the same place, and in substantially the same manner, as the magnetic coupling  116 . 
         [0033]    The guard arms  102  are designed for permanent mounting to the cabinet  101 . As shown in the side perspective view of  FIG. 3A , the guard arms  102  are attached to an outer fastening plate  104  which acts as one part of the fastening mechanism that secures each guard arm  102  to the cabinet  101 . A corresponding inner fastening plate  106  on the inside of the cabinet  101 , shown in the top plan view of  FIG. 3B , completes the attachment of each guard arm  102  to the cabinet  101 . In certain embodiments, only the outer fastening plate  104  may be needed to secure a guard arm  102  to the cabinet  101 . For example, the outer fastening plate  104  may be welded or adhered to the cabinet  101 . 
         [0034]    The size of the fastening plates  104 ,  106  and the materials of which they are made may vary from embodiment to embodiment. Considerations that may be taken in account when selecting the materials of the fastening plates  104 ,  106  include the weight of the guard arms  102 ; the motion, stresses, and wear and tear of pivoting the guard arms  102  into their respective resting positions; the stresses of attaching the caution and barrier system  100  to the cabinet  101  or other equipment; and the stresses and wear and tear on the locking mechanism  114  to put the guard arms  102  into the vertical position. Aluminum is one suitable material for the fastening plates  104 ,  106 , although in other embodiments and installations, other types of plastic or metal may be used. 
         [0035]    The outer fastening plate  104  may include a number of openings  122  to accommodate a range of fasteners, such as bolts, screws, posts or rivets, and openings  122  may be threaded or non threaded depending on the fasteners selected. The number of openings  122  may vary depending on the specific application of the caution and barrier system  100 , and each one of the openings  122  may vary in size and characteristics, but in the embodiment depicted in  FIGS. 1 and 2 , four openings are included in the outer fastening plate  104 . 
         [0036]      FIG. 3B  shows the details of the fasteners used to mount and secure the guard arms  102 . Specifically, the pivot post  110  may be a partially threaded or unthreaded fastener of a material capable of supporting the weight and pivoting action of the guard arms  102 , and may attach to the inside fastening plate  106  by means of, for example, complementary engaging screw threads, adhesives, press-fitting, welding, or any combination of attachment means, depending on the application. In some embodiments, the pivot post  110  may be a simple shaft, and the guard arm  102  may rotate about it. In that case, a between the guard arm  102  and the outside fastening plate  104 , a friction relief mechanism, such as a washer made of a low friction material like plastic, may be provided to aid the pivoting motion of the guard arm  102 . However, the rotation mechanism may be more complex in other embodiments. For example, the pivot post  110  could be associated with a bearing or bushing which supports the guard arm  102  in rotation and reduces both frictional forces and wear. 
         [0037]    A rod of suitable material may act as a resting post  112  for the guard arm  102  to rest on top of while in the horizontal position and to stop the movement of the guard arm  102  past the vertical or 90-degree position. The resting post  112  may be non-threaded or semi-threaded, as depicted in  FIG. 3B , and may be attached to and/or engaged with the outer fastening plate  104  in any suitable fashion. 
         [0038]    As shown, the locking tab  114  can be placed through an opening in the outer fastening plate  104 , transit the wall of the cabinet  101 , and lock into the inner fastening plate  106 . 
         [0039]      FIG. 3C , a exploded perspective view, shows the opening  128  for the locking tab  114 , used when the locking tab  114  secures the arm  102  in a vertical position, as well as additional openings  122  in the outer and inner fastening plates  104 ,  106  that allow these plates  104 ,  106  to be attached to the cabinet  101  and other surfaces.  FIG. 3C  also illustrates that the magnetic coupling  116  has fastener openings  132  in it, and corresponding openings  134  are provided in the front ends of the guard arms  102  to secure the magnetic couplings  116 . 
         [0040]      FIG. 3D , a side elevational exploded view, illustrates the arrangement of the pivot post  110 , resting post  112 , guard arm  102 , magnetic coupling  116 , washer  108 , outer fastening plate  104  and inner fastening plate  106 . 
         [0041]    As those of skill in the art will realize, although the guard arms  102  may be made in any length necessary to create a safe space around a piece of equipment  101 , particularly long lengths may be difficult to manufacture and cumbersome to ship and use. To address this issue,  FIG. 4 , a perspective view of a hinged guard arm caution and barrier system, generally indicated at  200 , includes a pair of hinged guard arms  202  that can be folded along their lengths. The system  200  is otherwise similar to the system  100  described above. However, the hinged arms  202  can be folded to more easily respect vertical and horizontal clearances, they can be manufactured in sections, and they can be handled more easily when folded for shipping and installation purposes. 
         [0042]      FIG. 5A  is an elevational view of a hinged guard arm  202  with the hinging mechanism  206  arranged such that each arm  202  can be folded inwards towards the cabinet  101 . The hinged guard arm  202  may utilize a common hinging mechanism  206  made of durable materials to support the weight and wear and tear of folding the hinged guard arm  202 . The embodiment illustrated in  FIG. 5A  utilizes four holes or openings  208  for the use of fasteners join the hinging mechanism  206  to two guard arm  202  segments. The number of holes or openings may differ from embodiment to embodiment considering factors such as height, weight, and number of sections making up each guard arm  202 . 
         [0043]      FIGS. 5B-5D  are top plan, perspective, and end elevational views, respectively, of one of the guard arms  202  in isolation. Except for the inclusion of the hinging mechanism  206 , the guard arms  202  are similar to the non-hinging embodiment of the caution and barrier system  100  described in  FIGS. 1-3D . 
         [0044]    As is apparent from the above description, systems  100  and  200  actually modify the piece of equipment  101 , typically by drilling or punching holes or openings in walls of the piece of equipment  101  to secure the guard arms  102 ,  202 . However, there will be situations in which this is not possible or not desirable. Therefore, other embodiments of the invention provide for attachment mechanisms that do not modify the piece of equipment  101 , as will be described below in more detail. These embodiments may also pivot by means described above. 
         [0045]      FIG. 6  is a perspective view of a caution and barrier system for electrical arcing generally indicated at  300 , with magnetic attachment and detachment. This embodiment utilizes a pair of magnetically attachable/detachable arms  302  that are mirror images of one another. Specifically, each arm  302  has one or more magnetic fasteners  306  embedded in it or attached to it near one of its ends. The magnetic fasteners  306  may be, for example, ceramic magnets or rare earth magnets that have sufficient magnetic attractive force to attach to a ferromagnetic wall of the piece of equipment  101 . Other embodiments may use suction cups or adhesives as fastening mechanisms. 
         [0046]    Each arm  302  also includes a handle  304 . The handles  304  may be composed of various materials. They may be molded or machined as part of the magnetically attachable/detachable arms  302 , or they may be separate removable components attached with fasteners such as bolts or screws. The handles  304  may be of the same or different materials than the arms  302  themselves. 
         [0047]      FIG. 7A  is a side elevational view of one of the magnetically attachable/detachable arms  302  in isolation. The magnetically attachable/detachable arms  302  may be, for example, a length of 48 inches in this embodiment. The handle  304  in this embodiment is positioned about 4 inches from the attachment end of the magnetically attachable/detachable arm  302  and extends along the length of and to the front of the arm  302 . 
         [0048]      FIG. 7A  and  FIG. 7B , a perspective view, illustrate the placement of three magnetic elements  306  within the guard arm  302 . In the illustrated embodiment, the magnetic elements  306  are depicted as embedded inline within the thickness of the arm  302 , allowing its outer surface to be contiguous, smooth, and to rest flush against the piece of equipment  101 . However, it should be understood that the magnetic elements  306  may be attached, for example, to the inner surface of each guard arm  302 , such that they are not embedded within it. 
         [0049]    Although the guard arms  102 ,  202 ,  302  were described above as being used in mirror-image pairs, in some embodiments, arms  102 ,  202 ,  302  of different types may be used together. For example, a hinging arm  202  may be paired with a non-hinging arm  102 . 
         [0050]      FIG. 8  is a perspective view of a freestanding caution and barrier system embodiment generally indicated at  400 , which in itself does not attach to any particular piece of equipment. This may be useful for providing a safe space for temporary work areas or for equipment or machinery for which there is no feasible means of attachment. The freestanding caution and barrier system  400  may comprise a guard arm  402  and a stand  403 . The guard arms  402  are similar to those described above containing indicia  120 , indicia plates  118 , or any other types of indicia including color as described above. The guard arm  402  may be any suitable length to provide the safe barrier needed to avoid opportunities for electrical arcing. 
         [0051]    The guard arms  402  rest on the stand  403  by way of a number of holding brackets  410 , each of which has a number of vertical support arms  406  intended to make contact directly or indirectly with the floor. Angled support arms  404  rigidify the structure of the stand  403  and provide support to the guard arm  402  along its length. The brackets  410  and guard arms  402  may include openings for fasteners similar to those described above. Angled support arms  404  may be at any angle, including completely horizontal. Footing structures  408  receive the arms  404 ,  406  and contact the floor. The stand  403  may be constructed of suitable materials, such as metals, plastics, or other natural or synthetic materials. In some embodiments, the stand  413  may be freestanding without the guard arms  402  inserted; in other embodiments, the holding brackets  410  may be collapsible and may require the guard arms  402  to form a freestanding, stable structure. 
         [0052]    Although a single guard arm  402  is supported by brackets at both ends in the illustrated embodiment, a single bracket may support the guard arm  402  in other embodiments, positioned either at one end of the guard arm  402  or in the center. That single bracket may be supported by a vertical support member with a suitable foot mechanism. 
         [0053]    In the description above, the guard arms  102 ,  202 ,  302 ,  402  are positioned in a single position, in most cases forward of the cabinet  101  or piece of equipment. However, in some cases, it may be useful for the guard arms to be positionable in different positions. 
         [0054]      FIG. 9  illustrates an embodiment of a caution and barrier system  500 , in which a guard arm  502  (only one guard arm  502  is shown in the view of  FIG. 9 , although the guard arms  502  would typically be used in pairs) is attached to a cabinet  101  or piece of equipment using a “universal” or “multi-position” mount  504 . 
         [0055]    The mount  504  itself has magnets on its rear surface that allow it to attach magnetically to the cabinet  101 . Specifically, two round magnets  506  are secured to the mount  504  by bolts, machine screws, rivets, or other fasteners  508 . (The two magnets  506  are shown in phantom in the view of  FIG. 11 .) In other embodiments, the base layer of the mount  504  may be made of a ferromagnetic material, making separately attachable magnets  506  unnecessary. 
         [0056]    The mount  504  is arranged to allow the guard arm  502  to extend either parallel to the mount  504  or angled with respect to it. Two raised guides  510 , which are metal blocks in the illustrated embodiment, define a slot  512  with a width just larger than the height of the guard arm  502 . That slot  512  accommodates and supports the guard arm  502  in either the parallel or angled positions. A pin  514  inserts through the top guide  510  into the guard arm  502  to retain it in the mount  504 . If the pin  514  is round, the guard arm  502  may pivot about it and thus be positioned at essentially any angle with respect to the mount  504 . On the other hand, if the pin  514  is square, triangular, or some other shape and is inserted into a hole  516  in the guard arm  502  that has a complementary shape, the shape of the pin  514  and the location of its faces will limit and define the angular positions in which the guard arm  502  can be placed.  FIG. 9  illustrates an angled position of the guard arm  502  in which the arm  502  extends perpendicular to the mount  504  and out to the side of the cabinet  101 . 
         [0057]      FIG. 10 , a side perspective view, illustrates the parallel position of the guard arm  502 , which is similar to the positions of the guard arms  102 ,  202 ,  302  of other embodiments. 
         [0058]      FIG. 11  is a cross-sectional view of the guard arm  502  taken through Line  11 - 11  of  FIG. 9 , illustrating the interaction of the pin  514  and the guard arm  502 . As shown, the guides  510  have openings, and the pin  514  transits those openings and the opening in the guard arm  502  to secure the guard arm  502  within the mount. 
         [0059]    Although the above description focuses on the attachment of the guard arms  102 ,  202 ,  302 ,  502  to a cabinet  101 , it should be clear that guard arms according to embodiments of the invention may be secured to any piece of equipment or any structure where a barrier is necessary. Additionally, although guard arms according to embodiments of the invention are particularly suited for use with electrical equipment, they can be used to form an effective barrier or secured space for any type of hazard. Moreover, they need not necessarily be attached to the same piece of equipment, so long as they extend in such a way to provide an appropriate barrier. 
         [0060]    While the invention has been described with respect to certain embodiments, the embodiments are intended to be exemplary, rather than limiting. Modifications and changes may be made within the scope of the invention, which is defined by the claims.