Abstract:
A safety gate system having an electronic display for seamless integration into a barrier with electronic display capabilities. The safety gate system includes a post and a gate hinged to the post. The gate face and post carry electronic display modules which appear when the gate is closed, as continuous with and seamlessly integrated into the display of the barrier. Preferably, the hinges are four-bar hinges, most preferably two sets of paired four-bar hinges. The safety gate also includes a lower chase or sill which allows both signal wiring and power to pass under the gate. Braced rear legs compensate for the cantilever forces of the gates when open. A latch, preferably an electromagnetic latch, auto-releases in response to a pre-set sufficient force level, such as arising crowd surge forces, being applied to the gate, as well as being remotely releasable.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
       [0001]    None. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is for controlling passage or access while providing an electronic display, and more particularly, pertains to a gate having electronic display capabilities and a variably controllable latch. 
         [0004]    2. Description of the Prior Art 
         [0005]    Barriers are typically employed for limiting passage or access of attendees at sports events and/or mass audience entertainment events. At musical concerts, barriers may keep attendees from physically interrupting a performance on stage. Barriers, such as those often situated about a soccer pitch periphery, serve to keep fans from interfering with athletes during an athletic match and may serve to limit fans to predetermined safe viewing locations. At the termination of an event, it may be desirable to enable passage through the barrier to facilitate fan dispersal. Additionally, in the event of a panic or stampede of a crowd of fans attending a mass event such as a soccer match, it may be desirable to allow incursions onto an athletic field or soccer pitch by enabling passage through the barrier so as to reduce crowd over-concentrations and the injuries which oftentimes may accompany surges of crowds of excited fans. 
         [0006]    One solution to allowing passage past a barrier has been to provide a lower receiving pit into which an entire barrier is recessed or lowered out of position, for example, by the use of hydraulics or pneumatics. Another solution to allow passage past a barrier is to include a horizontal hinge near the base of a barrier, then tip the barrier forward, thereby allowing passage by walking over the now horizontally oriented back of the barrier. In a more traditional solution, the barrier is permanently mounted and multiple traditional gates are provided. However, traditional gates typically require attendants or officials to release each gate. The first solution is undesirable because the accepting pit is expensive and a large capital investment is required. Further, significant safety concerns accompany each lowering of a barrier while a crowd is in intimate contact with the moving barrier. A hinge-to-horizontal barrier also is costly and is prone to safety concerns if tipped while in contact with a crowd. The traditional gate solution, while initially less costly, remains highly labor intensive and still undesirable from a safety stand point because each gate relies upon the cool-headedness of each live attendant performing a task in a potentially life threatening crowd incursion situation. 
         [0007]    From a communications perspective, there has been a modern trend to provide displays of graphics, information, and even animation for entertaining and communicating with fans at sporting events and/or mass audience entertainment. Such displays may convey messages of team support, game data, song lyrics and/or advertising on the barriers. Such displays also increase the attention and entertainment aspect of telecasts or films of the event. One especially versatile display is an electronic display. Modern electronic displays often employ a modular arrangement and may vary the electronic display depending upon context. As such, they also possess the ability to convey safety instructional messages in context to fans when appropriate. It would be desirable to modify a barrier to include one or more gates, each with advanced safety and control features, while still providing an uninterrupted or uniform arrangement of electronic display continuing through closed gates of the barrier. Such a system would include controlled latching of each gate, incorporating both remote release or opening of each gate when appropriate, along with automatic context-sensitive release or opening of the gate, particularly during emergencies, such as crowd surges. 
       SUMMARY OF THE INVENTION 
       [0008]    The general purpose of the present invention is to provide a safety gate system with an electronic display. 
         [0009]    According to one embodiment of the present invention, there is provided a safety gate system can be integrated into a barrier system with electronic display capabilities so as to allow controlled passage through the barrier system either automatically or by remote release of latched gates. The safety gate system includes a post, preferably two posts spaced apart from each other; a gate hinged to the post and movable between a closed position or condition disallowing passage through the barrier system, and an open position or condition allowing passage through the barrier system. Preferably, the gate is one of two paired gates. Each gate of the pair is hinged and/or carried by one of the preferred two posts. A latch system holds the gate or gates in the closed position or condition; and the gate or gates has/have a face substantially providing an electronic display which appears substantially seamlessly integrated into the electronic display capabilities of the barrier system. Preferably, the electronic display capabilities of both the barrier system and the electronic display of the face of the gate employ electronic display modules mounted in a matrix or grid or array arrangement. That is, an array of rows and columns of electronic display modules, which together convey an impression of seamless integration into a single large display format. Preferably, the gates hold or carry a three horizontal row by four column array, the posts hold or carry a three horizontal row by two column array, such that a two post/two gate system carries or holds three horizontal rows by twelve vertical columns. Preferably, the latch of the safety gate system auto-releases when subjected to sufficient opening force, such as the force from a surging crowd, more preferably a force from about 1 kg to about 30 kg, and most preferably a force of about 20 kg. The latch may also be remotely released. The auto-yielding release and remote release of the gate or gates allow crowds of fans to disperse in a safe manner, for example, by providing necessary egress points from a stadium onto a pitch at a crowded soccer match. The gate or gates preferably have a biasing means, more preferably a pneumatic strut or struts to urge the gate or gates from closed toward open. Preferably, the hinges are four-bar hinges, more preferably there are four four-bar hinges, the four four-bar hinges being parallel and vertically spaced apart from each other, with two upper four-bar hinges paired together by a hinge coordinator plate and two lower four-bar hinges paired together by another hinge coordinator plate. This type of hinge accommodates the thickness of display carried by the gate to be rotated out and away from the stationary frame with minimal rubbing and binding of moving parts. Additionally, the four-bar hinge arrangement allows for the gates to eccentrically move about pivot points of a short bar and a long bar of the four-bar hinge. This four-bar hinge linkage arrangement resulting in conveying the impression that the gates first move forwardly, toward the pitch, then swing perpendicular to the barrier. Electrical wiring cable conduit is flexible and passes near the hinges to carry power and signaling to the display modules on the gates. The four-bar hinges allow the gate to initially move toward the front then transition to generally pivotably move toward perpendicular to its initial closed position. The system, in closed position and the electronic display modules mounted therein, appears to seamlessly integrate into the repetitive matrix pattern of the barrier display. In one embodiment, the safety gate system of the present invention may be used as an entrance to and exit from athletic playing fields, for example, in soccer matches. In such an embodiment, the safety gate system may be incorporated into a soccer pitch perimeter display to allow uninterrupted video display around a soccer match. In another embodiment, this gate system may also be used to control access to storage space located rearward of a barrier electronic display while providing an apparent seamlessly integrated electronic display on the front face. In such an embodiment, the auto-release force of the latch may be set lower so that stadium personnel need only give a sufficient pull force to open and reveal storage space behind the gate. In such an embodiment, the auto-release latch may be frictionally, magnetically or mechanically operated or some combination thereof. 
         [0010]    The present invention is also a method of controlling access though a barrier with an electronic display capability. The method includes the steps of providing an electronic display capability gate including a post, a gate hinged to the post and movable between a closed condition and an open condition, a lower electronic wire chase compartment underlying the gate in the closed condition and a latch; providing a gap in the barrier corresponding to the electronic gate width; installing the electronic gate and post in the gap; and latching the gate in the closed condition. Preferably, the gate is one of two gates, each carried by a separate post. The preferred two gates are preferably magnetic latched with a latch yield automatically occurring when subjected to a force, preferably a force associated with or near an arising dangerous crowd surge, for example, and most preferably a force of about 20 kg. Preferably, the gate or gates are capable of providing a seamless display across digital electronic display modules carried on the gate front face when the gate is closed. 
         [0011]    One significant aspect and feature of this invention is the ability to have part or all of an electronic display capable of swinging open. 
         [0012]    Another significant aspect and feature of this invention is the gas shock/pneumatic device mounted on the swinging gate and post to aid in opening and keeping open the swinging gate portion of the display. 
         [0013]    Still another significant aspect and feature is the adjustable force setting required to open the gate in an emergency. 
         [0014]    Yet another significant aspect and feature of this invention is the safety provided to fans in an enclosed setting by providing necessary egress points from the stadium onto the pitch. 
         [0015]    One more significant aspect and feature is the concealed cabling to prevent tripping hazards. 
         [0016]    Still a further significant aspect and feature is the fully enclosed mechanism and eased or beveled edges to eliminate clothing catches or snags. 
         [0017]    Still another significant aspect and feature is the module/alignment between barrier, gate and post. 
         [0018]    One more significant aspect and feature is the ability of the present invention to interconnect with existing reconfigurable pitch perimeter displays, such as the ProPitch™ system of Daktronics of Brookings, S.D. 
         [0019]    Still one more significant aspect and feature is the electromagnetic remote control used to control the latch mechanism. 
         [0020]    Finally another significant aspect and feature of this invention is providing a low cost emergency exit system for sports fields. 
         [0021]    Having thus described certain significant aspects and features of the present invention, one principal object of the present invention to provide a controlled opening gate or gates in an electronic display formed of electronic display modules which are seamlessly integrated into the electronic display of the barrier. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein: 
           [0023]      FIG. 1  is an isometric view taken from the upper left front of a safety gate system with electronic display, the present invention, shown with the gates in a closed configuration and with louver covered display modules, barrier electronic displays, in ghost, are also depicted to the right and left; 
           [0024]      FIG. 2  is an isometric view taken from the upper right rear of the safety gate system with electronic display, previously shown in  FIG. 1 , shown in with the gates in a closed configuration; 
           [0025]      FIG. 3  is an isometric view taken from the upper left front of the safety gate system with electronic display, previously shown in  FIG. 1 , shown with the gates in an open configuration and with top and shield components separated and some display modules and louvered panels removed or separated for facilitation of understanding and comprehension; 
           [0026]      FIG. 4  is an isometric view taken from the upper left rear of the safety gate system with electronic display, previously shown in  FIG. 1 , shown in with the gates in an open configuration and with display modules and louvered panels removed or separated for facilitation of understanding and comprehension; 
           [0027]      FIG. 5  is an isometric view taken from the upper rear right of the safety gate system with electronic display, previously shown in  FIG. 1 , shown with the gates in a closed configuration and with top structure and shields separated; 
           [0028]      FIG. 6  is a fragmentary enlarged top view showing detail of a representative four-bar hinge in closed condition; 
           [0029]      FIG. 7  is a fragmentary enlarged top view showing detail of a representative four-bar hinge in intermediate condition between closed and open conditions; 
           [0030]      FIG. 8  is a fragmentary enlarged top view showing detail of a representative four-bar hinge in closed condition; and, 
           [0031]      FIG. 9  is a fragmentary enlarged isometric view showing details of the right gate and four four-bar hinges thereof in open condition with some portions foreshortened to reveal details thereof. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0032]      FIG. 1  is an isometric view of a safety gate system  10  of the present invention, shown aligned within and filling a gap in a barrier  12  (shown in ghost) or, alternatively, replacing a length or segment of barrier  12 . As such, the safety gate system  10  may be considered a safety barrier or part of a safety barrier. It should be understood that the safety gate system  10  of the present invention also can be used in plural aligned arrangements of end-to-end safety gates  10 , thereby forming a safety barrier. Preferably, safety gate systems  10  of the present invention can be situated at desirable locations along the barrier  12 , such that the safety gate systems  10  may yield and thereby open at a preselected force pushing against the gates. Alternatively, the safety gate system  10  may be remotely opened. Opening of the safety gate system  10  reduces the pressure of a crowd of fans, thereby crushing injuries typically experienced by fans in dangerous crowds may be reduced or avoided. The safety gate system  10  of the present invention, in a preferred embodiment, includes a front face  14  which is directed toward a pitch, field, or stage situated opposite fans. The front face  14  is covered by electronic display modules  16  ( FIG. 3 ), most preferably display modules of U.S. Pat. No. 7,055,271 entitled “Electronic Display Module Having a Four-Point Latching System for Incorporation into an Electronic Sign”, incorporated by reference herein in its entirety. Each electronic display module  16  preferably has a louver panel  18  visible from the pitch, which louver panel  18  functions to protect players or equipment from contact with the electronic display module  16  while providing shade to LEDs of the electronic display module  16 . Such louvered panels  18  have been previously described in U.S. application entitled “Thermoplastic Elastomer Protective Louver Covering For Use with an Electronic Display Module”, application Ser. No. 11/589,405 filed Oct. 30, 2006, incorporated by reference herein in its entirety. Additionally, each electronic display module  16  has a latch mechanism for easy and rapid four-point attachment to the front face  14  of the safety gate system  10 , and thereby may be removed and repaired or replaced simply and quickly. The electronic display modules  16  are aligned and arranged in a grid arrangement of rows and columns and are connected to power and communications circuits within the safety gate system  10 . The power and communication circuits of the safety gate system  10  connect, in turn, to power and communications circuits within the barrier  12 . The safety gate system  10  includes a right post  20 , a left post  22 , a right gate  24  carried by and movable relative to right post  20 , and a left gate  26  carried by and movable relative to the left post  22 . Deployed in arrays of rows and columns on front face  14  are a plurality of electronic display modules  16 , including louver panels  18 . Suitable and preferred electronic display modules  16  are available from Daktronics, Inc. of Brookings, S.D. These electronic display modules  16  have been previously incorporated into other electronic signs and scoreboards as arrays. Together, the array is driven by computer directed power, signaling and display software to display a large message display extending over several or many or even the entire array of electronic display modules. In a preferred embodiment, the safety gate system  10  may be interconnected mechanically and electrically with the ProPitch™ reconfigurable pitch perimeter display system which is also available from Daktronics, Inc. of Brookings, S.D. The ProPitch™ reconfigurable pitch perimeter display system is a modular advertising and entertainment display system providing a color LED display directed toward a soccer pitch from the soccer pitch perimeter. It is reconfigurable in that it is modular and uses removable alignment pins between horizontally aligned modules, along with a single wrench latch mechanism between modules, a single connector for power between modules, and a single connector for its control signal between modules. In particular, the right post  20  and the left post  22  connect or latch mechanically and electrically for power and control signal with the ProPitch™ reconfigurable pitch perimeter display system. In such a use, the array or matrix of electronic display modules gives the impression of a continuous and seamlessly integrated display characterized by a general impression that electronic display modules are not separately identifiable as gates within the pitch directed display barriers. The same seamlessly integrated effect observed in the Daktronics, Inc.&#39;s ProPitch™ display is continued through the front face  14  of the safety gate system  10  when aligned and connected with the barrier  12  formed from ProPitch™ reconfigurable pitch perimeter display systems. That is, a fan situated across the pitch, field or stage viewing the front face  14  of the safety gate system  10 , as well as viewing the pitch directed face of the barrier  12  adjacent the safety gate system  10  when the right gate  24  and the left gate  26  are closed, receives the visual impression of a continuous visual display or message incorporating the front face  14  of the safety gate system  10 . Further, the resulting large message displays often are animated to better attract attention and/or provide a more eye-appealing display. 
         [0033]    As shown in  FIG. 2 , a rear face  28  of the safety gate system  10  is directed toward fans and away from the pitch. Affixed message placards or paint may be visible on the rear face  28 . Such message placards or paint may be advertising, or more preferably, safety instructions to fans. Alternatively, the fan-directed messages of the rear face  28  may be displayed by electronic displays which can be activated to visually alert fans with a safety message, for example, that the right and left gates  24  and  26  are opening. The right gate  24  is carried, in part, on the top right four-bar hinge  30  on the right post  20 , and the left gate  26  is carried, in part, by the top left four-bar hinge  42  on the left post  22 . The four-bar hinges  30  and  42  are accompanied by other four-bar hinges, as will be shown subsequently. An important safety feature of the safety gate system  10  is a latch projection  54  carried by the right gate  24  opposite the top-right four-bar hinge  30 . Note that the latch projection  54  has eased or beveled corners  55  to avoid or reduce snagging clothing during opening. A magnetic mating latch  56 , complementary to the latch projection  54 , is carried by the left gate  26  opposite top-left four-bar hinge  42 . Together, the latch projection  54  and the magnetic mating latch  56  hold the right and left gates  24  and  26  in closed condition/position as fans or crowds of fans push against the right and left gates  24  and  26 . When the force reaches a selected level, preferably an adjustable level, for example from about 1 kilogram to about 30 kilograms, most preferably about 20 kilograms, the latch projection  54  and the magnetic mating latch  56  separate and yield to the force of the crowd of fans. The right and left gates  24  and  26  then move toward the front face  14  or pitch. In one embodiment, a rare earth permanent magnet may be used in the latch projection  54  to provide magnetic attraction to the magnetic mating latch  56 . In another embodiment, the latch projection  54  is an electromagnet, which when remotely activated is attracted to the magnetic mating latch  56 . In both embodiments, the magnetic mating latch  56  may be a steel plate within or upon the left gate  26 . Due to the four-bar hinges  30  and  42 , the motion of the right and left gates  24  and  26  is both controlled and complex. Initially, each right gate  24  and left gate  26  moves toward the pitch or the front face  14 . However, this initial opening motion begins to increasingly involve motion near the latch projection  54  and the magnetic mating latch  56 . Simultaneously, at the four-bar hinges  30  and  42  (and other corresponding four-bar hinges), the initial opening motion begins to increasingly involve rotation about pivots of the four-bar hinges  30  and  42 . As the opening motion continues to conclusion, the right and left gates  24  and  26  reach an open position/condition roughly perpendicular to the closed position/condition. A right reduced gate section  25  and a left reduced gate section  27  preferably is included on the right gate  24  and left gate  26 , respectively, in the region of the latch projection  54  and the magnetic mating latch  56 , and where the left and right gates  26  and  24  meet. These right and left reduced gate sections  25  and  27  further serve to facilitate closing or opening without binding interference. As such, the right and left reduced gate sections  25  and  27  work in cooperation with the four-bar hinges  30  and  42  to provide smooth opening and closing substantially free of interference. The safety gate system  10  may be permanently mounted or, alternatively, may be used as a temporary installation, for example, as part of a temporary barrier. In such temporary installations, it is desirable to employ a right rear vertical channel  58  mounted on the rear face of the right post  20 , and similarly a left rear vertical channel  66  mounted on the rear face of the left post  22 . The right and left rear vertical channels  58  and  66  are pivotably attached, respectively, to the right rear leg  60  and the left rear leg  68 , and further stability is provided by pivotably attaching a right brace  62  and a left brace  70 . Additionally, while the safety gate system  10  is depicted as vertically arranged, there may be situations where it is desirable for either atheistic or functional purposes to incline the safety gate system  10  either toward the front face  14  or toward the rear face  28 . One typical reason is an incline already present in the adjacent barrier  12 , in some cases such barrier inclinations are intended to improve the angle and view of fans or cameras present at the event. To accommodate such nonperpendicular arrangements between the right and left rear vertical channels  58  and  66  and the right and left rear legs  60  and  68 , respectively, a plurality of attachment positions, preferably on the right and left rear legs  60  and  68 , or alternatively, on the right and left vertical channels  58  and  66 , respectively, are pivotably and adjustably connected by pins  64  and  72 , respectively. Another reason for employing a nonperpendicular arrangement of the right and left rear legs  60  and  68  is to accommodate sloped, nonlevel or otherwise uneven ground supporting the safety gate system  10 . When attached to the supporting ground, the right and left rear vertical channels  58  and  66 , the right and left rear legs  60  and  68 , the right and left braces  62  and  70 , and the pins  64  and  72  serve to stabilize the safety gate system  10 , particularly when the right and left gates  24  and  26  are in an open condition/position cantilevered relative to the right and left posts  20  and  22 . Additionally, stability is afforded the safety gate system  10  when crowds of fans push against the right and left gates  24  and  26  prior to release of the latch projection  54  from the magnetic mating latch  56  at a preselected sufficient force, for example, a pushing force of about 20 kilograms. 
         [0034]    As shown in  FIG. 3 , when the right and left gates  24  and  26  are in the open condition/position, the right and left gates  24  and  26  are in a cantilevered condition relative to the right and left posts  20  and  22  of the safety gate system  10 . The right and left rear legs  60  and  68  and right and left braces  62  and  70  (shown in  FIG. 2 ) serve to counteract the cantilevered right and left gates  24  and  26 . A lower chase or sill structure  74  provides space for the right and left gates  24  and  26  to move without catching on the ground of the pitch or field during opening or releasing when the magnetic interaction of the latch projection  54  yields and separates from magnetic mating latch  56 . The lower chase or sill  74  also serves to maintain consistent spacing and vertical orientation between right and left posts  20  and  22 . Significantly, the lower chase or sill  74  provides an internal pathway through which wire cabling for power and signaling may be lead both from and/or for portions of barrier  12  adjacent either side of the safety gate system  10 . This, in turn, leads to added safety in that fans are precluded from contact with wire cabling which could be either an electrical or tripping hazard if such were not passed through lower chase or sill  74 . Broad relationships of the several four-bar hinges are now described, additional narrow detail of representative four-bar hinge  30  is available from observation and description of sequential  FIGS. 6 ,  7  and  8 . The top right four-bar hinge  30  is an upper member of four right four-bar hinges aligned in parallel and carrying the right gate  24  on the right post  20 . The top right four-bar hinge  30  is paired with an upper mid right four-bar hinge  32 . To reduce binding and assure smooth action of the paired four-bar hinges  30  and  32 , an upper right hinge coordinator plate  34  is attached to long bars  106  of the right four-bar hinges  30  and  32 , thereby maintaining a parallel and coordinated relationship between these two hinges. A lower mid right four-bar hinge  36  and a bottom right four-bar hinge  38  are similarly stabilized by a lower right hinge coordinator plate  40  attached to long bars  106  of the lower mid right four-bar hinge  36  and the bottom right four-bar hinge  38 . A mirror image of the top right four-bar hinge  30 , the upper mid right four-bar hinge  32 , the lower mid right four-bar hinge  36 , and the bottom right four-bar hinge  38 , as well as the upper right hinge coordinator plate  34  and the lower right hinge coordinator plate  40 , is present between the left post  22  and the left gate  26 , in that the left top four-bar hinge  42  is paired with an upper mid left four-bar hinge by an upper left hinge coordinator plate  46  being attached to the long bars  106  of such hinges and a lower mid left four-bar hinge  48  paired with a bottom left four-bar hinge by a lower left hinge coordinator plate being attached to long bars  106  of such hinges. Also shown in  FIG. 3  is the grid pattern of rows and columns for accepting the electronic display modules  16  and the louver panels  18  thereon. Preferably, the right and left gates  24  and  26  each have three rows and four columns and the right and left posts  20  and  22  each have three horizontal rows and two vertical columns. When closed, the safety gate system  10  shows three horizontal rows and twelve vertical columns. When display power and control are applied, the array of thirty-six preferred electronic display modules  16  appear as one integrated display. When inserted in the barrier  12  of  FIG. 1  with a similar three horizontal row display, the safety gate system  10  when closed appears to be integrated into the barrier  12  and the electronic display module  16  provided on the barrier  12 . 
         [0035]    As shown in  FIG. 4 , a right post/hinge extension  21  is attached to the right post  20  and encloses and carries the top right four-bar hinge  30 . The upper mid right four-bar hinge  32 , the lower mid right four-bar hinge  36 , and the bottom right four-bar hinge  38  are also attached to the right post/hinge extension  21  as shown in  FIG. 3 . A left post/hinge extension  23  attached to the left post  22  encloses and carries the top left four-bar hinge  42 , as well as other attached hinges including an upper mid left four-bar hinge, a lower mid left four-bar hinge, a bottom left four-bar hinge corresponding to other previously just described like and similar components. The rear face of the right and left post/hinge extensions  21  and  23  serve to also shield sport spectators from exposure to the multiple four-bar hinges enclosed and carried therein. Additionally, the right and left post/hinge extensions  21  and  23  are located rearwardly to provide clearance for opening the right and left gates  24  and  26  as the right and left gates  24  and  26  have a generally thinner or narrower front-to-rear section than the right and left posts  20  and  22 . Further, the right and left post/hinge extensions  21  and  23  serve to prevent sport spectators access or exposure to flexible wire cables providing power and signaling to the right and left gates  24  and  26 . Power and signaling to the electronic display modules  16  on the front face  14  of the right and left posts  20  and  22  may be led directly upward in wire cables from the lower chase or sill  74 , whereas wire cabling carrying power and signaling to the right and left gates  24  and  26  must be flexible to accommodate the motion of the right and left gates  24  and  26  relative to the right and left posts  20  and  22 . A right pneumatic device  76  is partially visible (and partially shown in ghost) to urge and bias the right gate  24  to an open position/condition. The right pneumatic device  76  is pivotably attached to the right gate  24  adjacent the top right four-bar hinge  30  and pivotably attached to the right post  20 . Another pneumatic device  78  is pivotably attached to left gate  26  adjacent the top left four bar hinge  42  and pivotably attached to the left post  22  and serves to urge and bias the left gate  26  to an open position/condition. 
         [0036]      FIG. 5  is an isometric view taken from the upper rear right of the safety gate system with electronic display, previously shown in  FIG. 1 , shown with the gates in a closed configuration and with top structure and shields separated. In particular as shown in separated fashion, a right post top cover  80  is used to cover the top of the right post  20 , a left post top cover  82  is used to cover the top of the left post  22 , a right gate top cover  84  is used to cover the top of the right gate  24 , and a left gate top cover  86  is used to cover the top of the left gate  26 . Shields having a slight curvature to facilitate shedding rain and/or beverages, cover and protect the right post top cover  80 , the left post top cover  82 , the right gate top cover  84 , and the left gate top cover  86 , as well as structures and devices situated below the right post top cover  80 , the left post top cover  82 , the right gate top cover  84 , and the left gate top cover  86 . In particular, a right post shield  88  protects the right post top cover  80  and the right post  20  thereunder; a left post shield  90  protects the left post top cover  82  and the left post  22  thereunder; a right gate shield  92  protects the right gate top cover  84  and the right gate  24  thereunder; and a left gate shield  94  protects the left gate top cover  86  and the left gate  26  thereunder. Optionally, while major portions of the posts and gates and covers may be metal, such as light gauge steel or aluminum, the shield may be made of a weather and sun resistant plastic or of light gauge metal coated with a weather and light resistant finish. 
         [0037]    As shown in  FIGS. 6 ,  7  and  8 , the top right four-bar hinge  30  is shown, as representative, in fragmentary enlarged detail in closed, intermediate and open conditions, respectively. The remaining upper mid right four-bar hinge  32 , the lower mid right four-bar hinge  36 , and the bottom right four-bar hinge  38 , align beneath the top right four-bar hinge  30  and operate similarly and simultaneously, and the opposing four-bar hinges operate in mirror fashion. The top right four-bar hinge  30  includes a short bar  100  having a pivotally connected frame end  102  and a pivotally connected gate end  104 . The top right four-bar hinge  30  also includes the long bar  106  having a pivotally connected frame end  108  and a pivotally connected gate end  110 . As previously mentioned, the long bar  106  is attached to the upper right hinge coordinator plate  34 , thereby linking the top right four-bar hinge  30  to underlying upper mid right four-bar hinge  32  through the similar long bar  106  of the upper mid right four-bar hinge  32 . The frame ends  102  and  108  are pivotally connected to the relevant right post/hinge extension  21  such that the short bar frame end  102  is closer to the right post  20  and the long bar frame end  108  is spaced apart from the short bar frame end  102 . Thus, the right post/hinge extension  21  provides a bar of the top right four-bar hinge  30 . The gate ends  104  and  110  are pivotally connected to the right gate  24 , such that long bar gate end  110  is closer to the right reduced gate section  25  of the right gate  24  and the short bar gate end  104  is spaced apart from the long bar gate end  110 . Thus, the right gate  24  forms a bar of the top right four-bar hinge  30 . Note that in the closed condition/position, the short bar  100  and the long bar  106  are spaced apart and generally, relatively, although not truly or fully, parallel to each other. As the right gate  24  progressively opens, the short bar  100  pivots more than the long bar  106  such that at an open position/condition the short bar  100  is oriented nearly perpendicular to the long bar  106 . While opening, the long bar  106  pivots roughly about 45 degrees about frame end  108 , while the short bar  100  pivots roughly about 100 degrees about frame end  102 . During this opening motion, the right gate  24  moves forward and slightly toward the opposing left gate  26  and away from the right post  20 . The right reduced gate section  25  also moves forward toward the pitch, such that interference is avoided. The latch projection  54  serves to push the left gate  26  open slightly ahead of the right gate  24  by acting upon the left reduced gate section  27  of the left gate  26 . The right pneumatic device  76  is also shown pivotally attached urging and biasing the right gate  24  from closed position/condition of  FIG. 6  through the intermediate position/condition of  FIG. 7  and toward the open condition/position shown in  FIG. 8 . 
         [0038]    As shown in  FIG. 9 , a view of the right gate  24  with an exploded view of the top right four-bar hinge  30  in the open condition/position and slightly vertically foreshortened is shown for purposes of demonstration and clarity to best show and reveal the long bar gate end  110  and the short bar gate end  104 . The long bar gate end  110  and the short bar gate end  104  are both pivotally connected to a rib  112  of the right gate  24 . The rib  112  is a three sided horizontally oriented member near the top of the right gate  24 . The rearward portion of the rib  112  is open and the short bar gate end  104  and the long bar gate end  110  are pivotable connected to the bottom side of the rib  112 , preferably by shoulder bolts. The rib  112  is notched on the bottom side to accommodate and allow the upper right hinge coordinator plate  34  to rotate with the long bar  106  while pivoting at the long bar gate end  110 . The upper mid right four-bar hinge  32  also has a long bar similar to long bar  106  connected to the upper right hinge coordinator plate  34  and at a long bar gate end is pivotally connected to an upper mid rib  114  of the right gate  24 . The upper mid rib  114  is also a horizontally oriented three sided member with the rearward portion open. In mirror fashion to the lower side of the rib  112 , the upper side of the rib  114  is notched so as to accommodate and allow the upper right hinge coordinator plate  34  to rotate with the long bar of the upper mid right four-bar hinge  32 . The long bar gate end and the short bar gate end of the upper mid right four-bar hinge  32  are connected to the upper side of the rib  114 , preferably by shoulder bolts. In similar fashion, a lower mid rib  120  and a bottom rib  122  are pivotally connected to gate ends of long bars of the lower mid right four-bar hinge  36  and the bottom right four-bar hinge  38 , respectively. The ribs  120  and  122  are each three-sided horizontally oriented members, open on their rearward portions. The rib  120  has a notch  124  on the bottom side to accommodate and allow the lower right hinge coordinator plate  40  to rotate with the long bar of the lower mid right four-bar hinge  36  and the rib  122  has a notch  126  on the upper side to accommodate and allow the lower right hinge coordinator plate  40  to rotate with the long bar of the bottom right four-bar hinge  38 . As mentioned earlier, the lower right hinge coordinator plate  40  connects the long bars of the lower mid right four-bar hinge  36  and the bottom right four-bar hinge  38 . The short bars of the lower mid right four-bar hinge  36  and the bottom right four-bar hinge  38  are also pivotally connected and moved as the short bar  100  of the representative top right four-bar hinge  30 , as depicted in  FIGS. 6 ,  7  and  8 . Correspondingly, the left gate  26  has mirror image notched ribs and the top left four-bar hinge  42 , and also includes the upper mid left four-bar hinge, the lower mid left four-bar hinge, and the bottom left four-bar hinge (not shown). The notched ribs in the left gate  26  accommodate and allow rotation of the upper left hinge coordinator plate  46  and lower left hinge coordinator plate in mirror image fashion to that described and shown for the right gate  24 . Preferably, the ribs  112 ,  114 ,  120  and  122  are reversible to reduce the number of parts maintained for manufacture of the right gate  24 . By appropriate manipulation, the ribs  112 ,  114 ,  120  and  120  may be oriented to accept the shoulder bolts and short and the long and short bars  100  and  106 . Also, the rib placement contributes to supporting the three horizontal rows of electronic display modules  16 . As shown in  FIG. 9 , in ghost, the ribs  112 ,  114 ,  120  and  122  are suitably secured to panels, for example, by screws, rivets, or spot welds, preferably to flanges on the ribs  112 ,  114 ,  120  and  122 , to contribute to grid structure. 
       Mode of Operation 
       [0039]    Operation of the safety gate system  10  of the present invention involves providing a safety gate system  10  installed in the barrier  12  and providing power and signaling for controlling displays of electronic display modules  16  carried on the front face  14 . This power and signaling may be connected to either the right post  20  or the left post  22 , preferably at or adjacent to the lower chase or sill  74 , and also such power and signaling may be passed through the lower chase or sill  74  and thence along to the opposite post, either left post  22  or right post  20 , to continue power and control to remaining portions of the barrier  12 . Employing software controls, such as, for example, those generated by a Venus® Controller and/or a V-Link® controller, both available from Daktronics, Inc. of Brookings, S.D., various graphics and/or messages may be displayed in an apparently seamlessly integrated fashion upon the safety gate system  10  and the barrier  12  due to matching of the spacing and alignment of the grid arrays or matrices of rows and columns therebetween. A circuit is also provided for controlling an electromagnet, if present, in the latch projection  54 . (Alternatively, the electromagnet might be substituted for the magnetic mating latch  56 . In such an alternative, the latch projection could include a steel plate.) The safety gate system  10  then may be employed to separate fans or attendees from a pitch, field, or stage. Under normal operating conditions during a sporting event or performance, the electromagnet circuit of the latch projection  54  or alternatively the magnetic mating latch  56  is activated, if present. At either the conclusion of the event or during a recognized dangerous crowd condition, the electromagnetic circuit for the latch projection  54  and the magnetic mating latch  56  may be deactivated, thereby releasing the right and left gates  24  and  26 , and assisted by biasing and urging from the right and left pneumatic devices  76  and  78 , the right and left gates  24  and  26  are moved from a closed position/condition to an open condition/position. This allows the crowd to access the pitch, field or stage and reduces the crowd density. The electromagnetic circuit for latching may be arranged to open all such controlled safety gates present at the event or only individually selected safety gate systems  10  associated with crowd trouble spots. If, however, a dangerous crowd condition or incursion develops either too rapidly or remains unnoticed, crowd pressure applied to the right and left gates  24  and  26  will cause the latch projection  54  to separate from the magnetic mating latch  56  so as to yield automatically and without need for remote intervention. This, in turn, causes the right and left gates  24  and  26  to move to the open condition/position and allows relief from the dangerous crowd pressure. Subsequently, the right and left gates  24  and  26  may be reset to a closed condition/position by re-energizing the electromagnetic circuit, if present, and then applying sufficient closing force to overcome the right and left pneumatic devices  76  and  78 . Note that the right gate  24  needs to be closed first and the left gate  26  closed second to accommodate the latch projection  54  carried on the rear face of the right gate  24 . 
         [0040]    Various modifications can be made to the present invention without departing from the apparent scope thereof.