Abstract:
Embodiments described herein relate to an apparatus for attaching elements of a magnetic field safety system to headwear worn by a worker. In various embodiments, the headwear includes a combination of a sounder device, light assembly, personal alarm device and power source.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/129,418, filed on Jun. 25, 2008, the subject matter of which is incorporated in its entirety by reference herein. 
    
    
     BACKGROUND 
     The present invention relates generally to safety systems at work sites, and in particular to personal alarm devices (PADs) for use with an interactive magnetic marker field and proximity warning system. Many methods have been devised to protect people from being struck, pinched, crushed or otherwise harmed by vehicles and mobile equipment. Such vehicles and mobile equipment may be used for above and below ground operations. Examples of the equipment include: road construction equipment such as trucks, road graders, rollers and pavers; surface mining equipment, such as for use with gravel and sand operations, front end loaders, trucks, dozers, conveyors and other items; underground mining equipment such as continuous miners, shuttle cars, conveyors, crushers, load-haul-dump vehicles, man-trips, tractors, and other items. The equipment also includes fork lifts, cranes, and trucks used at warehouses and shipping ports. 
     The invention is particularly applicable to work sites that require personnel to be in close proximity to various hazardous elements, such as machines, mobile equipment, remotely controlled machines, and operated vehicles. Such work environments may include locations that are inherently dangerous and should be avoided or entered only with great caution. Examples of such work environments are surface mining, underground mining, sand and gravel operations, road construction, warehouses, shipping docks, coke plants, etc. Hundreds of people are killed each year in the U.S. in such work environments. Workers are sometimes struck, pinched, crushed or otherwise harmed while performing their jobs in such environments. Collisions between the various elements at the work sites need to be avoided also to avert property damage. 
     Referring now to  FIG. 1 , there is illustrated a simplified example of a work site in which a proximity detection system is implemented.  FIG. 1  shows a truck  304  on which a magnetic field generator  81  is mounted. The magnetic field generator  81  generates a magnetic field  92  that surrounds the truck  304 . The edge of the magnetic field  92  generated by the magnetic field generator  81  corresponds to the border of a Warning or Danger Zone surrounding the truck  304 . A worker  301  within the boundary of the Warning or Danger Zone  92  is in potential danger from being struck or otherwise injured by the truck  304 . The worker  301  carries a personal alarm device  60 . If the worker  301  and, correspondingly, the personal alarm device  60  are within the magnetic field  92  created by the magnetic field generator  81 , the personal alarm device  60  detects the presence of the magnetic field  92  and issues a visual or audio warning. In embodiments of the magnetic field warning system, as detailed in U.S. patent application Ser. No. 11/984,824, which is incorporated herein by reference in its entirety, multiple magnetic filed generators  81  may be used to generate Warning and Danger Zones having a complex shape around the truck  304  or other equipment or areas. These zones may be adjusted in both size and shape. In addition, safe zones may be designated near the truck  304  in which a personal alarm device  60 , while within the magnetic field  92 , does not generate a warning signal to the worker  301 . 
       FIG. 2  is a diagram of the personal alarm device  60  and the magnetic field generator  81  of the proximity detection system of  FIG. 1 . A magnetic field generator  80  is contained within a housing  81  and includes an amplifier  84  connected to a ferrite core  90 , inductor  86  and capacitor  88 . In addition, the magnetic field generator  80  is connected to a power source  83  that provides the power to operate the magnetic field generator  80 . The amplifier  84  is connected to and controlled by a controller  82 . The ferrite core  90 , inductor  86  and capacitor  88  generate a magnetic field  92  in response to an input voltage from the amplifier  84 . The amplifier  84  is controlled by the controller  82  which controls the voltage and current outputs of the amplifier  84 . The controller  82  is also connected to a receiver  96  and warning system  98 . The receiver  96  is connected to an antenna  94  which receives an input signal  76  from a personal alarm device  60 . The antenna  94  conveys the signal  76  to the receiver  96  which passes the signal  76  to the controller  82 . Upon receiving the signal  76  from the personal alarm device  60 , the controller  82  directs the warning system  98  to issue a warning. In one embodiment, the warning system  98  may issue an audio and/or visual warning. In another embodiment, the warning system  98  may be capable of terminating the operation of a vehicle to which the warning system  98  is mounted, for example, the truck  304  of  FIG. 1 . The magnetic field generator  80  may also be mounted in a location in which it is desirable to warn a worker carrying a personal alarm device  60  of their proximity to the location. 
     The personal alarm device  60  has x, y, and z axis magnetic field antennas  62  that sense the magnetic field  92  produced by the magnetic field generator  80 . The sensed magnetic field signal  80  is passed through filters  66  and an amplifier  68  to a signal detector  64 . The signal detector  64  then passes information about the detected signal to a controller  70 . The controller  70  activates a transmitter  72  which transmits a corresponding response signal  76  to the magnetic field  92  through an RF antenna  74 . In one embodiment, the response signal  76  is an RF signal. The personal alarm device  60  is powered by power source  71 . The personal alarm device  60  is carried by the worker  301  ( FIG. 1 ) in order to provide the worker with a warning of their proximity to a magnetic field generator  80 . 
     It has been found however, that existing personal alarm devices have not been worn or used effectively by workers. One issue is that workers are resistant to wearing devices that are bulky, uncomfortable to wear, and are located where they get in the way of the worker&#39;s activities. Existing personal alarm devices are typically placed in the pocket or onto a belt of a worker. As such, sounds emitted by the personal alarm devices may not be heard in a noisy environment. Moreover, visual indicators, such as lights, may not be seen by the worker to alert the worker of impending danger. What is needed, is a personal alarm device configured to be worn by a worker such that any signal—audio, visual, or both—transmitted by the personal alarm device will be readily and quickly recognized by the worker. Also needed is a personal alarm device that is miniaturized so as not to be obtrusive or uncomfortable when worn by the worker. 
     SUMMARY 
     In one embodiment described herein, a personal alarm device includes a controller, and a warning device electrically coupled to the controller, the warning device including a sounder device adapted to be positioned proximate to a worker&#39;s ear. 
     In another embodiment described herein, a personal alarm device includes a controller, and a warning device electrically coupled to the controller, the warning device including a visual indicator positioned proximate to a worker&#39;s line of sight. 
     In another embodiment described herein, a safety system includes a magnetic field generator, and a personal alarm device. The personal alarm device includes an antenna configured to detect a magnetic field, a controller electrically coupled to the antenna, and a warning device electrically coupled to the controller. The warning device includes a sounder device adapted to be positioned proximate to the worker&#39;s ear, and a visual indicator adapted to be positioned proximate to the worker&#39;s line of sight. 
     In another embodiment described herein, a method of warning a worker of danger includes generating a magnetic field using a magnetic field generator, detecting the presence of the magnetic field using a personal alarm device worn by the worker, wherein the personal alarm device comprises a sounder device arranged proximate to the worker&#39;s ear and a visual indicator arranged proximate to the worker&#39;s line of sight, and activating the sounder device and visual indicator light assembly to provide the worker a warning when the personal alarm device detects the magnetic field 
     The above and other advantages and features of the invention will be more clearly understood from the following detailed description which is provided in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an exemplary work site at which a proximity detection system is implemented. 
         FIG. 2  is a diagram of a personal alarm device and magnetic field generator of the proximity detection system of  FIG. 1 . 
         FIG. 3  is a diagram of a personal alarm device mounted on a hard hat in accordance with an embodiment described herein. 
         FIG. 4  is a side-view of the personal alarm device of  FIG. 3 . 
         FIG. 5  is a diagram displaying the dimensions of the personal alarm device of  FIG. 3 . 
         FIG. 6  is a diagram of a worker equipped with a personal alarm device/battery assembly and sounder/light assembly in accordance with an embodiment described herein. 
         FIG. 7  is a side view diagram of the light assembly and sounder unit of  FIG. 6 . 
         FIG. 8  is a top view diagram of the light assembly and sounder unit of  FIG. 6 . 
         FIG. 9  is an electrical diagram of a personal alarm device in accordance with an embodiment described herein. 
         FIG. 10  is an electrical diagram of a personal alarm device in accordance with another embodiment described herein. 
         FIG. 11  is a diagram of a personal alarm device mounted on a hard hat in accordance with another embodiment described herein. 
         FIG. 12  is a diagram of a personal alarm device mounted on a hard hat in accordance with another embodiment described herein. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments that may be practiced. These embodiments are described in sufficient detail to enable those of ordinary skill in the art to make and use them, and it is to be understood that structural, logical, or procedural changes may be made to the specific embodiments disclosed herein. 
     With reference to  FIG. 3 , there is shown an exemplary embodiment of a hard hat  100  that is worn by a worker in an operational environment. The hard hat  100  may instead be any other suitable headwear, including a helmet, sports hat, baseball cap, head band, winter hat, visor, or other type of headwear. The front end of the hat  100  shown in  FIG. 3  has a bill or visor (brim)  106  on which a personal alarm device  110  is mounted. In various embodiments of the invention, the personal alarm device  110  may be mounted in the center of the brim  106 , towards the side of the brim  106 , or in other locations on the brim  106  of the hat  100 . The personal alarm device  110  includes a warning device, such as a visual indicator  116 , which can include light indicators, such as LED&#39;s, a screen, such as an LCD screen, or other visual indicators. As shown in the embodiment of  FIG. 3 , the personal alarm device  110  is located on the brim  106  of the hat  100  such that the light indicators  116  are visible to a worker wearing the hat  100 . In other embodiments, the visual indicator  116  may be located remotely from the personal alarm device  110 . As shown in  FIG. 3 , the personal alarm device  110  may be mounted or attached to the brim  106  of the hat  100  by an attachment means. In one embodiment, the attachment means may be a clip  112  having one or more thumbscrews  114 . The clip  112  has a slot  113  that fits over the brim  106  of the hat  100 . The thumbscrew  114  may be tightened to secure the clip  112  and personal alarm device  110  to the brim  106 . In another embodiment, the clip  112  may be spring loaded. To attach the spring loaded clip to the hat  100 , a worker would merely need to open the clip and allow the clip to close on the brim  106  of the hat  100 . In addition to the clip  112 , the attachment means may be an adhesive, hook and loop fastener, tape, bolt, or other suitable means of attachment. 
     In other embodiments, the personal alarm device  110  including the visual indicator  116  or the remote visual indicator  116  may be mounted on a worker at a location such that the visual indicators  116  are proximate to a line of sight of the worker. The term “proximate to a line of sight” is defined as a location in which the visual indicator will be visible to a worker&#39;s direct vision or peripheral vision, and may include, for example, locations such as a worker&#39;s neck or a collar of the worker&#39;s shirt, a worker&#39;s shoulder, a worker&#39;s chest or shirt, the worker&#39;s wrist, a worker&#39;s headwear, a worker&#39;s glasses or goggles, a stalk or swivel mounted on a worker, or anywhere else on the worker&#39;s person that is easily and readily visible. In various embodiments, the personal alarm device  110  or a remote visual indicator  116  could be attached to the worker by such devices as a necklace, a wrist band, glasses, goggles, a collar clip, a shirt clip, a shoulder strap, and the like. 
     As shown in  FIG. 3 , a warning device including an audible sounder  102  is located remotely from the personal alarm device  110  at the back of the hat  100  and is attached to the personal alarm device  110  by a ribbon cable. The sounder  102  may include such devices that produce an audible warning such as a horn, a buzzer, a bell, a speaker, or other devices. The sounder  102  is preferably positioned such that sound is projected downward and toward the worker&#39;s ears. Alternatively, the sounder  102  may be located inside the hat  100 . In one embodiment, the sounder  102  may be mounted to the side of the hat  100  directly above a worker&#39;s ears. In another embodiment, the sounder  102  may be incorporated into the personal alarm device  110  such that the personal alarm device  110  and sounder  102  are one unit. In another embodiment, the sounder  102  may not be mounted on headwear at all. 
     In other embodiments, the personal alarm  110  device including the sounder  102  or a remote sounder  102  may be mounted on a worker at a location such that the sounder  102  is located proximate to the worker&#39;s ear. The term “proximate to a worker&#39;s ear” is defined as a location in which the sounder  102  will have a direct and unobstructed path to the worker&#39;s ear and may include, for example, locations such as a worker&#39;s neck or a collar of the worker&#39;s shirt, a worker&#39;s shoulder, a worker&#39;s chest or shirt, the worker&#39;s wrist, a worker&#39;s headwear, a worker&#39;s glasses or goggles, a stalk or swivel mounted on a worker, or anywhere else on the worker&#39;s person that has an unobstructed path to a worker&#39;s ear. In various embodiments, the personal alarm device  110  or remote sounder  102  could be attached to the worker by such devices as a necklace, a wrist band, glasses, goggles, a collar clip, a shirt clip, a shoulder strap, and the like. 
       FIG. 4  is a side-view of the personal alarm device  110  of  FIG. 3 . In the embodiment shown in  FIG. 4 , the personal alarm device  110  may have two thumbscrews  114  for attaching the personal alarm device  110  to the hat  100 . The personal alarm device  110  has a visual indicator  116 , also called a light assembly. The visual indicator  116  has three light indicators  118 ,  120  and  122 . In one embodiment, the light indicators  118 ,  120  and  122  may be blue, yellow and red, respectively. In use, the blue light indicator  118  indicates power and/or satisfactory status, the yellow light indicator  120  indicates a warning signal, and the red light indicator indicates a danger signal. Alternatively, the personal alarm device  110  can have just one light indicator  118 ,  120  or  122 . In use, the one light indicator flashes at different rates to indicate status as follows: a slow-rate flash indicates power and/or satisfactory status; a medium-rate flash indicates a warning signal; and a fast-rate flash indicates a danger signal. The personal alarm device  110  shown in  FIG. 4  also has an integrated audible sounder  104  for emitting an audible alarm during warning and/or danger conditions. The integrated audible sounder  104  may be used in combination with or in place of the audible sounder  102  shown in  FIG. 3 . 
       FIG. 5  is a diagram displaying the dimensions of a personal alarm device  111  in accordance with an embodiment described herein. The preferable size for the personal alarm device  111  using current components is shown in  FIG. 5 . It should be appreciated that the current preferable size of the personal alarm device  111  is only one example and that the size could be adjusted based on smaller available electronic components or other preferences. In one embodiment, the personal alarm device  111  has an overall length  124 , an overall width  126 , and an overall thickness  128 . Preferably, the length  124  is approximately 2 inches, the width  126  is approximately 3 inches, and the thickness  128  is approximately 0.75 inches. When attached to the hat  100 , the length  124  is the front to back dimension, and the width  126  is the left to right (across the brim  106 ) dimension. With such dimensions, the personal alarm device  111  is sufficiently miniaturized to unobtrusively fit onto the hat  100 . 
       FIG. 6  is a diagram of a worker  130  equipped with a personal alarm device/battery assembly  136  and sounder/light assembly  138  in accordance with an embodiment described herein.  FIG. 6  shows a worker  130  and different embodiments of the invention in use. The worker  130  has a belt  134 , and attached to the belt  134  is a personal alarm device/battery assembly  136 . The worker&#39;s hat  100  has a cap light assembly  132 . The cap light assembly  132  may include a switch for turning on/off the PAD/battery assembly  136 . The worker&#39;s hat  100  has attached a sounder/light assembly  138  for emitting audible and/or visual alarms. The sounder/light assembly  138  communicates via a cable  135  with the PAD/battery assembly  136 . The sounder/light assembly  138  is located on the hat  100  in such a position so as to be visible and audible to the worker  130  or otherwise proximate to the worker&#39;s ear and line of sight. For instance, the sounder/light assembly  138  may be mounted in various locations on the worker&#39;s hat or at other locations proximate to the worker&#39;s ear and line of sight as described above. The embodiment of  FIG. 6  allows further down-sizing of the invention because only the sounder/light assembly  138  is located on the hat  100 . The remainder of the personal alarm device components, including the power source, are located in the personal alarm device/battery assembly  136  which is worn on the belt  134 . It should be appreciated that the personal alarm device/battery assembly may be located elsewhere on the worker  130  and is not limited to being worn on the belt  134 . 
     The worker&#39;s hat  100  also has arranged on it a cap light assembly  132  that may be powered by the power source of the personal alarm device/battery assembly  136 . The cap light assembly may also include an LED lamp to illuminate the area in front of the worker  130 . In one embodiment, the cap light assembly may be integrated with the sounder/light assembly  138 . 
       FIG. 7  is a side view diagram and  FIG. 8  is a top view diagram of the light assembly and sounder unit  138  of  FIG. 6 . The sounder/light assembly  138  may include an audible sounder  102  and LED lights  116  as described with reference to  FIGS. 3 and 4 , above. The sounder/light assembly  138  communicates via a cable  135  with the personal alarm device/battery assembly  136  to warn a worker of dangerous conditions. The sounder/light assembly  138  may include a thumbscrew  114  and a slot  115 . In one embodiment, the slot  115  may be positioned around the brim  106  (not shown) of headwear  100  (not shown). Once the slot  115  is positioned around the brim  106 , the thumbscrew  114  may be tightened by a worker  130  (not shown) to secure the sounder/light assembly  138  to the brim  106  of the headwear  100 . 
       FIGS. 9 and 10  illustrate exemplary electrical diagrams of the various embodiments.  FIG. 9  shows an electrical diagram that corresponds to the embodiments shown in  FIGS. 3-5 .  FIG. 9  shows the personal alarm device  110 , which may have an internal battery pack  140  and/or an external battery  144 , which may also be a cap light battery. The external battery  144  may be worn on the worker&#39;s belt  134  (not shown), or at another suitable location and is connected to the personal alarm device  110  by an external battery cable  244 .  FIG. 9  also shows an external sounder  102  connected to the personal alarm device  110  by a sounder cable  210 . The personal alarm device  110  may also have audio and/or visual indicators  214  that are internal to the personal alarm device  110 , as discussed above with respect to  FIGS. 3 and 4 . In one embodiment, a charging plug may be inserted into a receptacle  145  on the external battery  144 , receptacle  146  on the sounder  102 , or receptacle  147  on the personal alarm device case  148  in order to recharge the external battery  144  or internal battery  140 . 
       FIG. 10  shows an electrical diagram that corresponds to the embodiment shown in  FIG. 6 .  FIG. 10  shows the personal alarm device  110  and battery  142  housed in a personal alarm device case  148 . The personal alarm device  110  is in communication with the sounder/light assembly  138  and the cap light assembly  132  through a sounder/light assembly cable  232 . The sounder/light assembly cable  232  splits into a sounder cable  210  that connects to the sounder unit  138  and a cap lamp cable  234  that powers the cap lamp  132 . The electrical configurations for the invention are designed to provide noise suppression utilizing hardware (e.g., filters  66  in  FIG. 2 ) and/or software (e.g., in the microcontroller  82  of  FIG. 2 ). In addition, the power supplies  142  are configured to provide a constant voltage to components. In one embodiment, a charging plug may be inserted into a receptacle  147  on the personal alarm device case  148 , receptacle  146  on the sounder  138 , or receptacle  149  on the cap lamp  132  in order to recharge the battery  142 . 
       FIG. 11  is a diagram of the personal alarm device in accordance with another embodiment described herein.  FIG. 11  shows a sounder  102  and cap light assembly  132  mounted on the front brim of a hardhat  100 . In the embodiment of  FIG. 11 , the personal alarm device  110  may include an internal battery  142  and be mounted on the side of the hardhat  100 . In another embodiment, the personal alarm device  110  may be mounted on the side of the hardhat  100  and an external battery pack  144  (not shown) may be mounted on the worker&#39;s belt (not shown) or elsewhere on the worker&#39;s person and connected to the personal alarm device  110  by a ribbon cable (not shown). 
     It should be appreciated that the personal alarm device  110 , sounder  102 , sounder/light assembly  138  and cap light assembly  132  may provide a variety of different warnings to the worker. For instance, the warning may be audio, visual, or tactile, such as vibrations. 
       FIG. 12  is a diagram of a personal alarm device  305  mounted on a hard hat  300  in accordance with another embodiment described herein. The personal alarm device  305  includes a warning device  306  and a controller  310 . The warning device  306  includes a sounder  302  and a light assembly  332  mounted on the front brim  307  of the hardhat  300 . In the embodiment of  FIG. 12 , the warning device  306  also includes a rechargeable battery  242 . The warning device  306  is connected to a controller  310  by a cable  335 . The cable  335  may transfer signals and commands from the controller  310  to the warning device  306  or vice versa. In one embodiment, the cable  335  may transfer electrical power from the rechargeable battery  242  to the controller  310 . In another embodiment, the controller  310  may have its own power source. The cable  335  may also have two connectors  230 ,  240  positioned along the cable. These connectors may be separated or joined in order to form an open or continuous connection between the warning device  306  and the controller  310 . In one embodiment, warning device  306  may replaced whenever any of its components wears out, becomes damaged, or is otherwise inoperable. When it becomes necessary to replace the controller  310  or the warning device  306 , the connectors  230 ,  240  may be separated and a new controller  310  or warning device  306  may be attached to the hardhat  300 . The connectors  230  and  240  are re-joined to one another after replacing the controller  310  or the warning device  306 . The warning device  306  may be separated or replaced at the same time. 
     In one embodiment of the invention, the controller  310  may have a battery charging receptacle  247  into which a battery charger may be connected in order to charge the battery  242 . In another embodiment, a battery charging receptacle  257  may be positioned along the cable  335  in order to charge the battery  242 . In yet another embodiment, a battery charging receptacle  246  may be attached to the connector  240  and/or  230 . In one more embodiment, a battery charging receptacle  245  may be positioned on the warning device  306 . In one embodiment of the invention, any combination of the battery charging receptacles  245 ,  246 ,  247 ,  257  may be used. 
     In the embodiment of  FIG. 12 , the controller  310  is attached to the side of the hardhat  300 . However, in another embodiment, the controller  310  may be attached to the back, front, or elsewhere on or in the hardhat  300 . In one embodiment, the warning device  306  is attached to the front of the hardhat  300 . In another embodiment, the warning device  306  may be attached to the side of the hardhat  300  or anywhere else on or in the hardhat  300  where the light assembly  332  would be easily visible to a worker wearing the hardhat  300 . For instance, the light assembly  332  may be mounted along the hardhat  300  in a location proximate to the line of sight of a worker wearing the hardhat  300 . 
     The above description and drawings are only illustrative of preferred embodiments of the present inventions, and are not intended to limit the present inventions thereto.