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You are an expert at summarizing long articles. Proceed to summarize the following text: 
FIELD OF THE INVENTION 
     The embodiments of the present invention relate to a construction zone safety system using radio frequency identification (“RFID”) devices or other signal-based devices. 
     BACKGROUND 
     Construction zone safety is critically important to all parties involved including, but not limited to, construction companies, construction workers, insurance companies, land developers and municipalities. The seriousness of construction zone safety is evidenced by the creation of the Occupational Safety and Health Administration (“OSHA”) which is tasked with monitoring construction zones as well as other areas. In one respect, OSHA is concerned with injuries or death of construction workers. 
     It would be advantageous to develop a signal-based safety system to reduce or eliminate injuries and accidents at construction zones. 
     SUMMARY 
     The embodiments of the present invention involve the use of one or more readers on heavy construction equipment (e.g., loaders) which detect signals emanating from signal transmitters on clothing or equipment of construction workers. In one embodiment, responsive to the detection of one or more signals emanating from behind a heavy piece of equipment, or in another position relative to the piece of heavy equipment, a controller integrated on the piece of heavy equipment causes the parking brake to be applied and/or transmission to be disengaged automatically without operator involvement. 
     In one embodiment, one or more readers are attached to the rear of the piece of heavy equipment and detect signals from RFID devices attached to the clothing or equipment of construction workers in the construction zone. The readers are positioned to capture signals from behind and/or along sides of the piece of heavy equipment. Hardware installed on the piece of heavy equipment serves to apply the parking brake of the piece of heavy equipment and/or disengage the transmission responsive to a controller signal. 
     In other embodiments, additional technology such as infrared sensors, acoustic sensors, thermal imaging sensors and/or cameras with human recognition may be used to locate workers near the piece of heavy equipment namely a danger zone. 
     Other variations, embodiments and features of the present invention will become evident from the following detailed description, drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1   a  and  1   b  illustrate an overhead view of a construction zone and danger zone utilizing a system/method according to the embodiments of the present invention; 
         FIG. 2  illustrates a rear view of a heavy piece of equipment with readers attached according to the embodiments of the present invention; 
         FIG. 3  illustrates a view of the parking brake lever and related mechanisms without the system detailed herein installed; 
         FIGS. 4   a - 4   c  illustrate views of a piece of heavy equipment with parking brake control mechanism installed according to the embodiments of the present invention; 
         FIG. 5  illustrates a view of portions of the parking brake control mechanism uninstalled according to the embodiments of the present invention; 
         FIG. 6  illustrates a block diagram of certain electrical components of the system according to the embodiments of the present invention; 
         FIG. 7  illustrates a block diagram of a system according to the embodiments of the present invention; 
         FIG. 8  illustrates a flow chart detailing a methodology of using the system according to the embodiments of the present invention; and 
         FIG. 9  shows a block diagram of a system according to the embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     For the purposes of promoting an understanding of the principles in accordance with the embodiments of the present invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications of the inventive feature illustrated herein, and any additional applications of the principles of the invention as illustrated herein, which would normally occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the invention claimed. 
     The embodiments of the present invention are directed to a system and method for protecting workers in construction zone by detecting the location of the workers in the construction zone and automatically, under certain conditions, controlling pieces of heavy equipment, such as loaders, bulldozers, excavators and the like, accordingly. 
       FIGS. 1   a  and  1   b  show overhead views of a construction zone  100  utilizing a system/method according to the embodiments of the present invention. A danger zone  110  is identified generally behind a piece of heavy equipment  120 . While the danger zone  110  is shown generally behind the piece of heavy equipment  120 , those skilled in the art will recognize that the danger zone  110  may be on either side or in front of the piece of heavy equipment  120  as well. As shown in  FIG. 2 , one or more interrogators or readers (also known as two-way radio transmitter-receivers (transceivers))  130 - 1  through  130 - 3  are attached to a rear portion of the piece of heavy equipment  120 . The readers  130 - 1  through  130 - 3  are configured to transmit signals to one or more RFID tags  140 - 1  through  140 -N and read a response from the RFID tags  140 - 1  through  140 -N. The RFID tags  140 - 1  through  140 -N are adhered to or contained within the clothing (e.g., vest) or equipment (e.g., hard hat) worn by construction workers in the construction zone. In one embodiment, as detailed below, the readers  130 - 1  through  130 - 3  transmit received signals to a controller  150  which is configured to control certain facets of the piece of heavy equipment  120  responsive thereto. 
     In one embodiment, the controller  150  is a processor on a circuit board driven by pre-programmed software or firmware linking the readers  130 - 1  through  130 - 3  with the controller  150  and hardware configured to automatically control the piece of the heavy equipment  120 . 
     As shown in  FIGS. 1   a  and  1   b , the danger zone  110  takes on a semi-circular zone dictated by the range of the RFID tags  140 - 1  through  140 -N and strength and position of the readers  130 - 1  through  130 - 3 . In one embodiment, the danger zone  110  is defined by a space ten feet laterally in both directions from the rear of the piece of heavy equipment  120 , eighteen feet diagonally from the rear of the piece of heavy equipment  120  and twenty-four feet directly rear of the piece of heavy equipment  120 . Construction zones include many obstacles such that the objective is to create a workable environment whereby the piece of heavy equipment is not being needlessly stopped. Thus, different construction zones may require danger zones of different dimensions and sizes. The contractor or other entity may determine the appropriate size of the danger zone for a given job. 
     In one embodiment, responsive to the piece of heavy equipment  120  being in a reverse gear, the readers  130 - 1  through  130 - 3  are activated such that the readers  130 - 1  through  130 - 3  begin to transmit signals receivable by RFID tags  140 - 1  through  140 -N which then transmit identification information (e.g., serial number associated with the RFID tag and worker identification information), to the readers  130 - 1  through  130 - 3 . The received information from the RFID tags  140 - 1  through  140 -N is, in one embodiment, transmitted to the controller  150  integrated into the piece of heavy equipment  120 . The controller  150 , using stored software, firmware and/or other pre-programmed code, evaluates the information signals received from the RFID tags  140 - 1  through  140 -N to determine a location of the RFID tags  140 - 1  through  140 -N relative to the piece of heavy equipment  120 . Responsive to the controller  150  determining that one or more of the RFID tags  140 - 1  through  140 -N are located in the danger zone  110 , the controller  150  causes application of the parking brake of the piece of heavy equipment  120  and/or disengagement of the transmission of the piece of heavy equipment  120  into a neutral position thereby stopping the piece of heavy equipment  120  from continuing in motion. Application of the parking brake may automatically move the transmission of the heavy piece of equipment  120  into a neutral position. 
       FIG. 3  shows standard parking brake lever  185  and linkage  186  which engages and disengages the parking brake via the parking brake lever  185 . The linkage  186  is driven by a rod and button apparatus or other parking brake control apparatus in the cab of the heavy piece of equipment  120 . Depression of the button causes the parking brake to be released while pulling of the button engages the parking brake.  FIGS. 4   a - 4   c  show views of a parking brake mechanism installed on the heavy piece of equipment  120  to facilitate automatic application of the parking brake responsive to receipt of a signal corresponding to a construction in a danger zone.  FIG. 5  shows views of the parking brake mechanism of the embodiments of the present invention uninstalled. The mechanism includes a controller  150  (shown in  FIG. 6 ), a pair of relays  151 ,  152 , a pull/hold coil  170 , solenoid  175 , and linkage  176  attached to parking brake lever  185 . A first relay  151  of 12V arms the system responsive to the piece of heavy equipment  120  being in a reverse gear. Responsive to a signal corresponding to a worker in the danger zone being received, the second relay  152  of 24V triggers the solenoid  175  forcing the linkage  176  to apply the parking brake. 
       FIG. 7  shows a block diagram  200  of a system according to the embodiments of the present invention. As detailed above, the system includes one or more readers  130 - 1  through  130 -N, RFID tags  140 - 1  through  140 -N, controller  150  and power source  160  for system components installed on piece of heavy equipment  120 . In one embodiment, an AC inverter converts DC power from the piece of heavy equipment  120  to drive the readers  130 - 1  through  130 -N and other electronic devices. The controller  150  communicates with a mechanical parking brake pull/hold coil  170  configured to physically apply the parking brake  195  of the piece of heavy equipment  120  which in turn automatically disengages the transmission and places the transmission into a neutral position. A solenoid  175 , when activated by the controller  150 , drives the pull/hold coil  170  which is attached to a parking brake lever  185  beneath the piece of heavy equipment  120  thereby moving the parking brake lever  185  causing the parking brake to be applied and the transmission to shift into the neutral position. Normally, a parking brake lever  185  requires 4-5 pounds of force to be applied and therefore the pull-hold coil  170  and solenoid  175  are configured to apply at least 5 pounds of force but ideally 7.5 to 10 pounds of force are applied. The parking brake pull/hold coil  170  may be installed to run parallel to the manual parking brake coil  190  which is installed at the factory during manufacture of the piece of heavy equipment  120  and is driven by manual actuation of the parking brake button  191  in the cab. An optional cab alarm  195  alerts the operator to the application of the parking brake lever  185 . Obviously, application of the parking brake lever  185  is immediately known to the operator given the sudden stop of the piece of heavy equipment  120  but the optional cab alarm  195  provides the operator with the reason for the sudden stop (i.e., not a mechanical failure). 
     Exemplary operation of the system is detailed in flow chart  300  of  FIG. 8 . At  305 , readers are positioned on a piece of heavy equipment and configured to define a desired danger zone. At  310 , RFID tags are placed on worker clothing and/or equipment and configured to transmit desired information carrying signals. At  315 , it is determined if the transmission of the piece of heavy equipment is in a reverse gear. If not, the flow chart  300  loops back to  315 . If so, at  320 , the readers are activated. At  325 , signals transmitted by said RFID tags are read by readers on a piece of heavy equipment. At  330 , signals received by said readers are transmitted to a controller. At  335 , the controller determines if the RFID tags are in the defined danger zone. If not, the flow chart  300  loops back to  325 . If so, at  330 , the controller triggers a solenoid to drive a pull/hold coil causing a parking brake lever to be engaged and parking brake to be applied and transmission shifted into neutral. At  335 , an operator of the piece of heavy equipment must manually disengage the parking brake from the cab once the danger zone is clear. 
     In one embodiment, as shown in block diagram  400  of  FIG. 9 , the system includes the components of block diagram  200  plus a transmitter  405  configured to send a signal to the pager, smart phone, personal digital assistant or other mobile device  410  of a construction site manager or other supervisory personnel. The signal may also be transmitted to a personal computer. The signal alerts the manager that the heavy piece of equipment  120  was forcibly stopped to prevent injury to one or more construction workers. This allows the manager to investigate and memorialize the incident. 
       FIG. 6  illustrates a block diagram  500  of exemplary electrical components of the system according to the embodiments of the present invention. As shown, a series of readers/antennas  505 - 1  through  505 - 3  communicate with switch  510  and uses a transmitter  515  to transmit a 928 MHz signal to the RFID tags and a receiver  520  to receive feedback signals from the RFID tags. A controller  525  communicates with the readers/antennas  505 - 1  through  505 - 3  and an optional user interface  530 . The controller  525  also communicates with (i.e., triggers) the parking brake mechanism. 
     Although the invention has been described in detail with reference to several embodiments, additional variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.

Summary:
A system incorporating one or more interrogators or readers on heavy construction equipment (e.g., loaders) detect signals emanating from signal transmitters on clothing or equipment of construction workers. Responsive to the detection of a signal emanating from behind the heavy equipment, or in another position relative to the heavy equipment, the driver is notified audibly of the danger such that the driver may stop the movement of the heavy equipment or causes the brakes to be applied and transmission to be disengaged automatically without operator involvement.