Patent Publication Number: US-2020290587-A1

Title: Wireless wheel chock

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of, and claims the benefit and priority of, U.S. patent application Ser. No. 15/402,232, filed on Jan. 9, 2017, which is continuation of, and claims the benefit and priority of, U.S. patent application Ser. No. 14/869,976, filed on Sep. 29, 2015, now U.S. Pat. No. 9,539,995, which is a non-provisional of, and claims the benefit and priority of, U.S. Provisional Application Ser. No. 62/056,849, filed Sep. 29, 2014. The entire contents of such applications are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The application relates to loading docks and particularly to a system and method for improving performance of loading dock wheel chock safety procedures. 
     Loading docks are among the most dangerous locations in a commercial space. Tractor trailer trucks need to maneuver outside the loading dock with limited space and limited visibility. Inside, fork lift trucks are moving about to and from the loading dock, also with limited space and limited visibility. Pedestrians can also be moving about both outside and inside the loading dock door. 
     One of the worst case accident scenarios at a loading dock can occur when a trailer unexpectedly moves away from the dock. If a forklift is between a surface of the dock and the entry to the trailer when the trailer unexpectedly moves, in almost all cases the forklift falls about four feet to the surface below the door. The forklift operator can be seriously injured, or worse, a portion of the forklift can fall on the driver causing in a fatal crush injury. 
     In response to such accidents, there are chock related OSHA regulations, as well as local regulations, and commercial rules regarding chock use at loading docks. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with one aspect of the disclosure, a wheel chock system includes a chock assembly comprising a wheel chock, a shaft, and a handle coupled to the wheel chock to place the chock against a tire of a truck or trailer wheel. A sensor disposed within the chock senses when the chock is in close proximity to the tire. The wheel chock system further includes an outside light box electrically coupled to the chock assembly. One or more lamps of the outside light box provide a visual indication of the proximity to the wheel based on the sensor, and to give one or more visual indications of a loading dock safety status. The wheel chock system further includes an inside control panel operatively coupled to the outside light box. One or more lights on the inside control panel provide a second visual indication of the loading dock safety status. The wheel chock system further includes a controller electrically coupled to the inside control panel. The controller includes a processor programmed to change visual indications of both the outside light box and the inside control panel, based at least on the sensor and a loading dock door sensor. The wheel chock system further includes a wireless module communicatively coupled to the controller to convey the loading dock safety status wirelessly over a network to provide an additional layer of wheel chock system safety oversight. 
     In accordance with one another aspect of the disclosure, a wheel chock system includes a chock assembly comprising a wheel chock, a shaft, and a handle coupled to the wheel chock to place the chock against a tire of a truck or trailer wheel. The wheel chock system further includes a sensor disposed within the chock to sense when the chock is in close proximity to the tire. The wheel chock system further includes an outside light box electrically coupled to the chock assembly. One or more lamps on the outside light box provide a visual indication of the proximity to the wheel based on the sensor and to give one or more visual indications of a loading dock safety status. The wheel chock system further includes an inside control panel operatively coupled to the outside light box. One or more lights on the inside control panel provide another visual indication of the loading dock safety status. The wheel chock system further includes a controller electrically coupled to the inside control panel. The controller includes a processor programmed to change visual indications of both the outside light signal box and the inside control panel, based at least on the sensor and a loading dock door sensor. The wheel chock system further includes a camera positioned to view the tire of the truck or trailer wheel and the chock. The camera is communicatively coupled to the wheel chock system to convey an image of the tire of the truck or trailer wheel and the chock to a display disposed on or near the inside control and light box to provide an additional layer of wheel chock system safety oversight. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The features described herein can be better understood with reference to the drawings described below. The drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. 
         FIG. 1  depicts an illustration of a wheel chock system as viewed from the truck side of a loading dock, according to one embodiment of the invention; 
         FIG. 2  depicts a schematic diagram illustrating a truck trailer backed up to a loading dock having a camera directed at the wheel chock and which shows a Wi-Fi module of an exemplary Wi-Fi wheel chock system; 
         FIG. 3  depicts a block diagram of a data processing system in which illustrative embodiments of the present invention may be implemented; 
         FIG. 4  depicts a block diagram of an exemplary wireless wheel chock system configuration where a computer with a wired or wireless connection to a local network can communicate via an access point with a wireless wheel chock system; 
         FIG. 5  depicts a block diagram of an exemplary wireless wheel chock system configuration where a computer with a wireless module can communicate directly with the wireless module of a wireless wheel chock system; 
         FIG. 6  depicts a block diagram of an exemplary wireless wheel chock system configuration where a computer with an internet connection can communicate via an access point with a wireless wheel chock system; 
         FIG. 7  depicts a block diagram of an exemplary wireless wheel chock system configuration where a wireless device with a wireless connection to a local network can communicate via an access point with a wireless wheel chock system; 
         FIG. 8  depicts a block diagram of an exemplary wireless wheel chock system configuration where a wireless device with an Internet connection to a local network can communicate via an access point with a wireless wheel chock system; 
         FIG. 9  depicts a simplified illustration of a properly chocked trailer tire; 
         FIG. 10  depicts a simplified overhead exemplary illustration of an incorrectly placed chock; 
         FIG. 11  depicts another simplified overhead illustration of an incorrectly placed chock; 
         FIG. 12  depicts a block diagram of an exemplary wireless wheel chock system configuration where a computer with a connection to a network can communicate with a wireless wheel chock system, and a wireless communication module is located in the chock; 
         FIG. 13  depicts a side perspective view of a wireless wheel chock assembly according to one embodiment of the present invention; 
         FIG. 14  depicts a left side plan view of the wireless wheel chock assembly shown in  FIG. 13 ; 
         FIG. 15  depicts a left side perspective view of the wireless wheel chock assembly shown in  FIG. 14  with the wheel chock housing removed for clarity; 
         FIG. 16  depicts a right side plan view of the wireless wheel chock assembly shown in  FIG. 13 ; 
         FIG. 17  depicts a right side perspective view of the wireless wheel chock assembly shown in  FIG. 16  with the wheel chock housing removed for clarity; 
         FIG. 18  depicts an exploded perspective view of the wireless wheel chock assembly shown in  FIG. 17 ; 
         FIG. 19  depicts a side plan view of the wireless wheel chock assembly shown in  FIG. 13  with the sensor in a first, pre-loaded position; 
         FIG. 20  depicts a magnified view of  FIG. 19 ; 
         FIG. 21  depicts a side plan view of the wireless wheel chock assembly shown in  FIG. 13  with the sensor in a second, intermediate position; 
         FIG. 22  depicts a magnified view of  FIG. 21 ; 
         FIG. 23  depicts a side plan view of the wireless wheel chock assembly shown in  FIG. 13  with the sensor in a third, maximum-travel position; 
         FIG. 24  depicts a magnified view of  FIG. 23 ; and 
         FIG. 25  depicts various plunger positions for a position switch according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Definitions: Wireless module: A wireless module includes any suitable form of wireless communications such as, for example, Wi-Fi, ZigBee, XBee, communication over power lines, or any other suitable form of wireless communications, such as any suitable type of radio frequency (RF) wireless communications. While referred to hereinbelow as a wireless “module”, wireless module is understood to include wireless functionality added by one or more wires, PC posts, or cables literally connected to a wireless module, as well as the equivalent wireless functionality on any suitable circuit board, such as can be provided by one or more discrete components and/or integrated and/or hybrid circuits mounted to one or more circuit boards associated with a controller. The method of construction such as, for example, through hole components, surface mount components, and or more compact technologies such as flip chips and/or other solder bump compatible packages are all understood to fall within the definition of wireless module as used hereinbelow. 
     Operatively coupled: Operatively coupled as used herein includes both wired and wireless connectivity such as any suitable form of communicatively coupled. For example, in practice, the “outside light box” is typically wired by a cable through a wall to an “inside light box” as described hereinbelow. However, it is unimportant to the new system and method how the outside box is operatively coupled to the system, typically receiving information from a controller which can be mounted inside the inside light box for convenience of packaging or in another enclosure, typically inside of the building, and typically mounted near the inside light box. For convenience of supplying power to the outside light box, the outside light box, again is typically hardwired to either the inside light box or another related electronics enclosure typically housing the controller electronics and ancillary contact devices, such as, for example electro-mechanical relays, or solid state switches used to control one or more series of lamps (e.g. a string of LEDs) in each of the light boxes. However, there can be embodiments, for example, where an outside light box receives power from an electrical power source independent of electrical power which powers the inside light box and/or the controller mounted inside of the loading dock. In such cases, it is contemplated that the outside light box can be wirelessly coupled to the controller (which may or may not be physically mounted in the inside light box) by any suitable wireless means, such as, for example, those used for the wireless module as described herein. A wirelessly coupled outdoor light box can be powered by any suitable means, such as, for example by one or more batteries of any suitable type (e.g. as charged by a local dedicated or non-dedicated photovoltaic panel and battery charger) or hardwired into any suitable source of AC power or DC power available outside of the loading dock near where the outside light box is mounted to the outside loading dock wall. 
     As described hereinabove, loading docks are among the most dangerous locations in a commercial space. Tractor trailer trucks need to maneuver outside the loading dock with limited space and limited visibility. Inside, fork lift trucks are moving about to and from the loading dock, also with limited space and limited visibility. Pedestrians can also be moving about both outside and inside the loading dock door. 
     One of the worst case accident scenarios at a loading dock can occur when a trailer unexpectedly moves away from the dock. If a forklift is between a surface of the dock and the entry to the trailer when the trailer unexpectedly moves, in almost all cases the forklift falls about four feet to the surface below the door. The forklift operator can be seriously injured, or worse, a portion of the forklift can fall on the driver causing in a fatal crush injury. 
     While, there are chock related OSHA regulations, as well as local regulations, and commercial rules regarding chock use at loading docks, such accidents still happen. 
     Much progress has been made towards improving loading dock safety. For example, through a combination of signal lights, audio alarms, and interlocks, the Smart Chock™ brand sensor system (available from DL Manufacturing of North Syracuse, N.Y.) has been widely used to enforce safe chock practice. However, even with the extensive use of the local signaling and alarming offered by the Smart Chock™ sensor system, a system and method which offers still more oversight and/or better enforcement of proper chock use and chock procedure at the loading dock is needed. 
     Furthermore, in facilities having a large number a loading docks, a logistics problem arose when engineers attempted to integrate wired wheel chock sensor input from numerous wheel chocks. Specifically, the system had to be “daisy-chained,” meaning each unit was tied to another in series, and the wheel chock sensor signals passed from one device to the next before finally arriving at an end interface. This scheme became prohibitive in terms of installation complexity and hardware costs when incorporating large numbers of units. The cost of running wires was unmanageable due to each facility&#39;s particular layout and floorplan—may had crowded and difficult-to-install areas that prevented running the large numbers of wires required to operate the system. 
       FIG. 1  shows an illustration of one exemplary embodiment of a wheel chock system  10  as viewed from the truck side of a loading dock  12 . For purposes of illustration and to further explain orientation of certain features of the invention, a lateral axis is defined as substantially parallel to the loading dock wall and is denoted as the x-axis; a longitudinal axis is defined as substantially in the direction of vehicle motion when backing into the loading dock and is denoted as the y-axis; and the vertical axis is denoted as the z-axis. The wheel chock system  10  includes a wheel chock assembly  14 , an exterior-mounted outside light box  16 , an interior-mounted inside control panel  18  (shown in dashed lines because it is located on the other side of the loading dock wall), and a controller  20 . In the illustrated embodiment, the controller  20  is disposed inside the inside control panel  18 . The outside light box  16  includes a green lamp  22 , a red lamp  24 , and a red chock icon  26 . The inside control panel  18  includes a green chocked lamp  28  and a red unchocked lamp  30 . 
     In operation, as a driver backs up to a closed overhead door, the green lamp  22  flashes on the outside light box  16 , indicating it is safe to proceed. A light baffle around the red and green lamps (typically high-brightness LEDs) cause the lights to be visible only to the driver in the cab of a truck in the lane corresponding to a particular loading dock. Concurrently, the inside control panel  18  illuminates the red unchocked lamp  30 , indicating the trailer is not chocked and it may be unsafe to open the overhead door. 
     After backing into the loading dock  12 , the driver locates the wheel chock assembly  14 , which can only be moved within a distance of that loading dock as set by the cable length. A cable pole  32 , such as a fiberglass pole, helps to keep the cable  34  off the ground and out of the way when the wheel chock assembly  14  is not in use ( FIG. 2 ). The driver can take hold of the wheel chock assembly  14  by a handle  36  at the end of a shaft  38 , such as a fiberglass shaft. The driver then follows safe wheel chock procedures and places the wheel chock  40  under the truck tire (not shown). In some embodiments, a non-skid saw-tooth back plate  42  helps to positively secure the back foot of the chock to the ground surface. 
     A sensor  44  may be operatively associated with the wheel chock system  10  to detect the presence of the chocked tire. In one possible implementation, the contact surface of the wheel chock  40  defines an aperture, and the sensor  44  is adapted to measure the presence of the truck tire through the aperture. The sensor  44  may be any type of data-gathering, data-transmitting device that is suitable for the conditions. In one example, the sensor  44  may be an ultrasonic device that includes an ultrasonic transducer or transceiver adapted to generate high frequency sound waves and evaluate the echo which is received back by the sensor. By measuring the time interval between sending the signal and receiving the echo, the sensor can determine if a truck tire is present over the aperture. In another example, the sensor  44  may be a proximity-sensing photoelectric sensor in which an emitter is adapted to transmit a beam of light (such as pulsed infrared, visible red, or laser) that diffuses through the aperture. As the wheel covers the aperture, part of the light beam deflects back to a receiver, detection occurs, and an output may be transmitted to a controller or microprocessor. 
     When the trailer is parked and chocked, the sensor  44  in the wheel chock  40  relays the condition to the controller  20 , which sends a command to illuminate the chock icon  26  and turn off the green lamp  22  on the outside light box  16 . With the outside red chock icon  26  illuminated, a driver checking the rear view mirror can positively see that the trailer wheel is still chocked. Concurrently, the red unchocked lamp  30  turns off and the green chocked lamp  28  illuminates on the inside control panel  18 , indicating the trailer is chocked and it is safe to open the overhead door. The inside control panel  18  is typically mounted to an inside wall in the immediate vicinity of a loading dock door (e.g., a sectional door) of the same loading dock, such as for example, by fasteners. The inside control panel  18  also may include an audio alarm  46  for alerting personnel to unsafe conditions as described in more detail hereinbelow. 
       FIG. 1  also depicts an exemplary trailer illumination lamp  48  having a flexible, adjustable shaft  50  to provide lighting inside the trailer for loading and unloading operations. After the loading dock door is opened, the adjustable shaft  50  may be positioned to point the lamp bulb (encased by bulb shield  52 ) into the trailer. In some embodiments, the adjustable shaft  50  may be formed of flexible stainless steel tube, and a cooling fan  54  located in a base housing  56  may push air through the flexible stainless steel tube to reduce the lamp bulb temperature, thereby extending the bulb service life. The base housing  56  may be mounted to an inside wall so as to prevent blocking the doorway. The illumination lamp  48  can also be used to supplement alarm signals, such as by blinking on and off. 
       FIG. 2  depicts a schematic block diagram showing a truck trailer  58  backed up to the loading dock  12 . The trailer  58  has been properly chocked by wheel chock assembly  14  placed against wheel  60 . Typically, a loading dock sectional door is opened, followed by operation of a loading dock leveler  62  to make a relatively flat bridge for personnel and forklifts to proceed to and from the loading dock and trailer. Once the leveler is correctly positioned, a personal safety restraint, such as a chain across the loading dock door, can be opened and loading or unloading operations can then safely proceed. Once the loading dock door has opened, the red lamp  24  on outside light box  16  illuminates to alert those outside in the same loading dock lane that the loading dock door is open. 
     Because loading dock operations can involve potentially dangerous activities, many embodiments of the exemplary wheel chock system  10  include various responses to the wheel chock sensor  44 , a door sensor  64 , and a safety chain sensor  66  (not shown) to automatically sense safety conditions and to alarm on detection of a unsafe loading dock condition. In one example, the outside light box  16  may include an audio alarm  46  for sounding during unsafe conditions as described in more detail hereinbelow. In another example, if wheel chock  40  is removed prematurely with the loading dock door open, the green chocked lamp  28  on the inside control panel  18  turns off, the red unchocked lamp  30  turns on, and an outside audio alarm  46  turns on. In yet another example, if the loading dock door opens without a truck wheel chocked, the illumination lamp  48  flashes and the inside audible alarm  46  sounds. Additionally, the outside red chock icon  26  turns off, the outside red lamp  24  illuminates, and an outside audio alarm  46  activates. In one exemplary system failure mode, if communication between the wheel chock assembly  14  and the inside control panel  18  is severed, lost, or disconnected, such as by severing chock cable  34 , the inside green chocked lamp  28  and red unchocked lamp  30  alternately flash from green to red, an on-board yellow system LED (not shown) illuminates, and the outside red lamp  24  illuminates. If the wheel was chocked, chock icon  26  turns off and outside audio alarm  46  sounds. 
     As can now be seen, the various lights and alarms of the exemplary wheel chock system are intended to guide the truck driver and personnel at the loading dock through a safe loading dock chock operation, including adherence to safe wheel chock procedures. When the wheel chock system detects a breach of the loading dock safety procedures or other safety hazard, the wheel chock system attempts to draw the attention of any personnel in the immediate location of the loading dock to an unsafe condition. 
     However, it has been realized that despite the numerous safety features described hereinabove, it may still be possible for personnel at the loading dock to defeat one or more interlocks or to defeat proper chocking such as, for example, by intentionally or accidentally causing wheel chock assembly  14  to indicate that it is correctly installed under a truck tire when it is not. While almost no commercial system can guarantee a perfectly failsafe operation, loading dock operations can be so hazardous and fast paced, it was realized that further levels of system safety monitoring are needed. 
     Accordingly,  FIG. 2  further depicts a truck trailer  58  backed up to the loading dock  12  and having a camera  68  pointed at the wheel chock  40 , and which shows a wireless module  70  of an exemplary Wi-Fi wheel chock system. The wireless module  70 , which may be a Wi-Fi module, is operatively coupled to inside control panel  18  by any suitable means, such as for example, via a serial connection such as by a RS/EIA/TIA-232 or RS/EIA/TIA-485 serial connection interface. An optional LCD display  72 , here provided as part of the inside control panel  18 , allows an operator to see the image from camera  68  and/or to read wheel chock system information directly at the loading dock. 
     The Wi-Fi portion of a wheel chock system allows for safety personnel to be able to actively monitor events on the loading dock, while not having to be physically present at the loading dock. Now, persons beyond the loading dock are able to access the loading dock information available from the wheel chock system of every loading dock door from any remote location with access to the Wi-Fi network in, such as, for example, via the Internet. 
     In one example, a worker opens a loading dock door to load a truck without the truck being properly chocked. The result is an alarm sounding as well as the safety personnel being wireless notified by any suitable means, such as, for example via their computer and/or smartphone and/or other suitable mobile device. 
     Along with enhanced safety, there can also be energy savings and environmental awareness by the addition of the wireless wheel chock system reporting features. For example, there can be energy conservation and monitoring by only allowing the loading dock Fan and Light to be on when the loading dock door is open through wired or wireless control means (e.g., wireless power control modules). 
     In another example, large facilities with a high number loading dock doors may desire to conserve as much energy as possible. With the wheel chock system monitoring system, users are able to monitor the time duration of light and/or fan operation and thus determine an approximate amount of power usage. Remote users can determine if the loading docks are consuming more power than intended by remote monitoring and take action to change the loading dock operation to better meet desired energy usage goals. 
     The monitoring system may also record occurrence times and calculate the time between events to obtain efficiency metrics. In one example, a large facility desires to increase the efficiency of loading dock times as much as possible. A user of the Wi-Fi wheel chock system and method as described herein is able to monitor, record, and study loading dock operation information as can be transmitted from the loading dock. 
     Because the loading dock is an entry portal into a commercial facility, loading dock information sent by the Wi-Fi wheel chock system and method as described herein (e.g., a door open event) can be used to enhance facility security monitoring. In one example, a particular company normally operates its loading dock only during regular business hours. A wireless communication from the wheel chock system indicates that a door has been opened during a time outside of normal operating hours. The monitoring system can also be set to specifically alert security personnel of loading dock events during a particular time period (e.g., outside of normal working hours) via text message/email/other to provide enhanced loading dock security. 
     The controller  20  can be communicatively coupled to the wireless module  70  by any suitable means. In some embodiments, wheel chocks can be coupled to the wireless module by a RS/EIA/TIA-232 or a RS/EIA/TIA-485 serial connection interface. 
     In one implementation, each wheel chock system  10  can be assigned a unique IP address. The IP address can be coded for a corresponding loading dock location. For example, a “loading dock  47 ” might be assigned the IP address 10.24.70.047 and a “loading dock  48 ” assigned an IP address of 10.24.70.048. The IP address can be entered into the Wi-Fi module  70  of a wheel chock system by any suitable IP address entry technique. For example, in embodiments with a touch sensitive LCD display  72 , or where there is a local keypad or keyboard, the IP address can be entered via the LCD display. The IP address can be set by a portable computer temporarily connected to the wireless module, such as through the RS-232 port on the conversion module. Or, in some embodiments, the IP address can be set or set wirelessly by accessing the RS-232 to Wi-Fi converter via a network access point (similar to configuring a router). 
     In some embodiments, the wheel chock system  10  can send wireless messages, such as wireless messages sent by a Wi-Fi module. Exemplary Wi-Fi wheel chock system messages—wireless (e.g., Wi-Fi) wheel chock system messages can be sent using any suitable characters or encoding. Exemplary messages include “CHOCKED”, “DOOR MOVING”, “DOOR OPEN”, “DOOR CLOSED”, “UNCHOCKED”, etc. Typically, unique names or codes are assigned to each message. For example, the message “CHOCKED” can be “:CHKD!”. The same message can be sent, for example, as an ASCII code, a HEX code, a binary code, or by any other suitable encoding method. There can be a character which announces a message, such as, for example “:”. There can also be a character to indicate the end of a message, such as, for example, “!”. The exact coding or format of a wireless wheel chock system message is unimportant to the system and method described herein. It is also unimportant if the actual coded message literally include letters representing a physical item. For example, the system can be configured to recognize the message “:2;T!” as meaning door moving. 
     Typically, an application program, such as, for example, any suitable executable code may be running on a computer or device intended to receive such wireless wheel chock system messages. In some embodiments, there can be two-way messaging, where, for example, a supervisor realizing an unsafe loading dock condition from received messages or other indication received at the remote location (e.g., an image as described hereinbelow), can stop or inhibit some or all loading dock functions by use of a remote computer or a remote mobile device. 
       FIG. 3  schematically depicts a block diagram of an exemplary data processing system  20  that may be utilized by and/or in the implementation of the present invention. The processing system  20  may be realized as a computer, controller, mobile device, or another type of device in which computer usable program code or instructions can implement the processes disclosed herein. Some of the exemplary architecture shown for and within data processing system  20 , including both depicted hardware and software, may be eliminated without departing from the general description of the operations and functions of data processing system described herein. Non-limiting examples of computers include servers, clients, laptop computers, or tablet computers. A non-limiting example of a controllers includes a microcontroller with somewhat limited functions and capabilities. Non-limiting examples of mobile devices include smart phones and personal digital assistants. 
     In the depicted example, data processing system  20  employs a hub architecture, such as North Bridge and memory controller hub  74 , and South Bridge and input/output (I/O) controller hub  76 . Processor  78 , main system memory  80 , and graphics processor  82  are coupled to the memory controller hub  74 . Processor  78  may contain one or more processors, may be a multi-core processor, and may be implemented using one or more heterogeneous processor systems. Graphics processor  82 , which drives/supports display  72  or other displays, may be coupled to memory controller hub  74  through an accelerated graphics port (AGP) in certain implementations. 
     In the depicted example, local area network (LAN) network adapter  84  is coupled to I/O controller hub  76 , and may include an RJ-45 jack and/or a wireless chip. I/O controller hub  76  affords communication with various I/O devices through I/O bus  86 . I/O devices can include for example audio adapter  88 , camera  68 , door sensor  64 , modem  90 , read only memory (ROM)  92 , universal serial bus (USB) and other ports  94  (which may include a USB keyboard and mouse adapter), Peripheral Component Interconnect (PCI)/PCI Express (PCIe) devices  96 , and various interlocks  98  that may be activated when pre-set conditions are satisfied. Exemplary interlocks  98  include commands to illuminate the lamps or indicators in the outside light box  16  and the inside control panel  18 . PCI/PCIe devices  96  may include, for example, flash memory devices, Ethernet adapters, add-in cards, and PC cards for notebook computers. PCI uses a card bus controller, while PCIe does not. ROM  92  may be, for example, a flash binary input/output system (BIOS). 
     Hard disk drive (HDD) or solid-state drive (SSD)  100  and CD-ROM  102  are coupled to I/O controller hub  76  through second I/O bus  104 . Hard disk drive  100  and CD-ROM  102  may use, for example, an integrated drive electronics (IDE), serial advanced technology attachment (SATA) interface, or variants such as external-SATA (eSATA) and micro-SATA (mSATA). Although not illustrated, a super I/O (SIO) device may be coupled to I/O controller hub  76  through I/O bus  86 . 
     Memories, such as main system memory  80 , ROM  92 , or flash memory (not shown), are some examples of computer usable storage devices. Hard disk drive or solid state drive  100 , CD-ROM  102 , and other similarly usable devices are some examples of computer usable storage devices including a computer usable storage medium. 
     An operating system runs on processor  78 . The operating system coordinates and provides control of various components within the data processing system  20 . The operating system may be a commercially available operating system for any type of computing platform, including but not limited to server systems, personal computers, and mobile devices. An object oriented or other type of programming system may operate in conjunction with the operating system and provide calls to the operating system from programs or applications executing on data processing system  20 . In one example, application programs may include programs and logic to initiate the interlock features  98  of the wheel chock system  10 . 
     Instructions for the operating system, the object-oriented programming system, and applications or programs are located on storage devices, such as in the form of code  106  on hard disk drive  100 , and may be loaded into at least one of one or more memories, such as main system memory  80 , for execution by the processor  78 . The processes of the illustrative embodiments may be performed by processor  78  using computer implemented instructions, which may be located in a memory, such as, for example, main system memory  80 , read only memory  92 , or in one or more peripheral devices. 
     Furthermore, in another example, code  106  may be downloaded over network  108  from remote computer  110 , where similar code  112  is stored on a storage device  114 . In another case, code  106  may be downloaded over network  108  to remote computer  110 , where downloaded code  112  is stored on a storage device  114 . 
     Data processing system or controller  20  is able to communicate with the remote computer  110 , which may include mobile devices, using network adapter  84  to accesses network  108 . Network interface  84  may be a hardware network interface, such as a network interface card (NIC), etc. Network  108  may be an external network such as the Internet, or an internal network such as an Ethernet or a virtual private network (VPN). In one embodiment, access to the network  108  is via a wireless access point  116  ( FIGS. 4, 6-8 ), which is a wireless modem that allows devices that are compliant with a wireless protocol (e.g., IEEE 802.11x—“Wi-Fi”) to wirelessly access network  108 . Note that wireless access point  116  affords mobile devices access to network  108  (e.g., the Internet), and also affords the controller  20  direct access to the mobile devices. 
     Other examples of the wireless network depicted by network  108  include, but are not limited to, a near field communication (NFC) network (in which devices communicate at ranges of 4 cm or less); personal area networks (PANs), such as those that use industrial, scientific, and medical (ISM) radio bands and protocols defined in the Institute of Electrical and Electronics Engineers (IEEE) 802.15.1 standard for wireless communications within a few meters; as well as a wireless local area network (WLAN), such as a Wi-Fi network, which enables wireless communication in a range of approximately 100 meters in accordance with the IEEE 802.11x standards. 
     Note that the hardware elements depicted in controller  20  are not intended to be exhaustive, but rather are representative of typical components which may be required by various embodiments of the present invention. For instance, controller  20  may include alternate memory storage devices such as magnetic cassettes, digital versatile disks (DVDs), Bernoulli cartridges, and the like. These and other variations are intended to be within the spirit and scope of the present invention. 
     Referring to  FIG. 4 , wherein like numerals indicate like parts from  FIGS. 1-3 , depicted is a block diagram of components in an exemplary wireless wheel chock system  410  configuration where a remote computer  4110 , such as a laptop, personal computer, or mobile device, having a wireless connection to a local network can communicate via an access point to receive wheel chock system information. The inside control panel  18  and controller  20  ( FIG. 1 ) may be operatively coupled to a wireless module  470 , such as a Wi-Fi module, by a RS/EIA/TIA-232 or a RS/EIA/TIA-485 serial connection interface  118 . The wireless module  470  can be mounted to the inside control panel  18 , to the wheel chock assembly  14 , or at any other suitable exterior or interior location. Typically wireless module  470  may be mounted near or within the inside control panel  18 , which can also house the controller  20 . In one embodiment of  FIG. 4 , wireless module  470  communicates data and information from the wheel chock system  10  via a local Wi-Fi network wireless point, such as, for example, Wi-Fi wireless access point  4116 . Any suitable computer  4110  can communicate via Wi-Fi  4120  with the local Wi-Fi network to receive wheel chock system information  4122  from Wi-Fi module  470 . 
       FIG. 4  also depicts an exemplary wireless wheel chock system  410  configuration where a computer cabled to a Wi-Fi access point can communicate via an access point to receive wheel chock system information. Wireless module  470 , which may be a Wi-Fi module, communicates wheel chock system information via a local Wi-Fi network wireless point, such as, for example Wi-Fi wireless access point  4116 . Any suitable computer  4110  directly wired  4124  to the wireless access point  4116  can communicate via the access point to receive wheel chock system information  4122  from Wi-Fi module  470 . 
     Referring to  FIG. 5 , wherein like numerals indicate like parts from  FIGS. 1-3 , depicted is an exemplary wireless wheel chock system  510  configuration where a computer with a Wi-Fi module can communicate directly with the Wi-Fi module of a wheel chock system  10  to receive wheel chock system information. Wireless module  570 , which may be Wi-Fi module, communicates wheel chock system information  5122  directly with any suitable computer  5110  having a Wi-Fi module to directly receive wheel chock system information from Wi-Fi module  570 . 
     Referring to  FIG. 6 , wherein like numerals indicate like parts from  FIGS. 1-3 , depicted is an exemplary wireless wheel chock system  610  configuration where a computer with an Internet connection can communicate via an access point to receive wheel chock system information. Wireless module  670 , which may be a Wi-Fi module, communicates wheel chock system information  6122  via a local Wi-Fi network wireless point, such as, for example Wi-Fi wireless access point  6116 . Any suitable computer  6110  connected to the Internet  6108  can communicate  6124  via Wi-Fi access point  6116  via the Internet to receive wheel chock system information  6122  from Wi-Fi module  670 . 
     Referring to  FIG. 7 , wherein like numerals indicate like parts from  FIGS. 1-3 , depicted is an exemplary wireless wheel chock system  710  configuration where a wireless device with a Wi-Fi connection to a local Wi-Fi network can communicate via an access point to receive wheel chock system information. As depicted by the dashed line, wireless module  770 , which may be a Wi-Fi module, can communicate wheel chock system information  7122  via a local Wi-Fi network wireless point, such as, for example Wi-Fi wireless access point  7116 . Any suitable wireless device, such as mobile device  7110 , which can access the local Wi-Fi network, such as, for example by Wi-Fi access point  7116 , can communicate via Wi-Fi access point to receive wheel chock system information from Wi-Fi module  770 . 
     Referring to  FIG. 8 , wherein like numerals indicate like parts from  FIGS. 1-3 , depicted is an exemplary wireless wheel chock system  810  configuration where a wireless device with an Internet connection to a local Wi-Fi network can communicate via an access point to receive wheel chock system information. Wireless module  870 , which may be a Wi-Fi module, can communicate wheel chock system information  8122  via a local Wi-Fi network wireless point, such as, for example Wi-Fi wireless access point  8116 . Any suitable wireless device, such as mobile device  8110 , which can access the Internet  8108  can communicate via Wi-Fi access point  8116  via the Internet to receive wheel chock system information from Wi-Fi module  870 . 
     Wired Embodiments: There may be installations where it is preferable to create the equivalent of the wireless network connections described in detail herein above in part or in whole by wired cables (e.g. a network of loading dock systems wired to one or more central computers or network hubs by a plurality of RS-485 cables). It is contemplated that such hardwired systems might be advantageous in commercial or factory settings with severe radio frequency interference (RFI) or severe electromagnetic interference (EMI) at or near the loading dock controllers. For hardware cabled networks of loading dock controllers, there can be dedicated controllers with any suitable form of digital outputs, such as, for example, digital line drivers to drive hardwired cables in particularly electrically noisy environment&#39;s. There can also be embodiments with both wireless connectivity and hardwired options available on the same controller board. There can also be embodiments with optional plug-in modules for either wireless connectivity or hardwired options (e.g. a cable line driver module) available on the same controller board. The exact physical configuration of wired or wireless electronic circuitry provided on or near a controller board (e.g. provided as a separate module, separate package, or as components mounted on or near the controller) which provides either wired or wireless connectivity for a network of loading dock controllers is unimportant to the new system and method of networking one or more loading dock controllers at a facility. 
     In some embodiments, using any of the communication methods described hereinabove, in addition to receiving wheel chock system information, there can be two-way communication between a remotely controlled component (e.g., some component of the building HVAC system near the loading dock such as a fan or adjustable vane) or a person at a remote computer or mobile device. For example in some embodiments, a fan commanded off can automatically reply that the fan is off. Or, in some embodiments a person at a remote computer can send a message that can be displayed on a display at the loading dock. 
     The wheel chock system  10  may also include a LCD display  72  that can display wheel chock system information. In some embodiments, the display can show a data log of events which occurred over a particular time period to a local user at the loading dock. Typically, any data such as data regarding wheel chock operation, loading door operation and data entered into, or displayed by a local display (e.g., a local LCD display) can also be transmitted to the network via any suitable wireless means, such as by a Wi-Fi module. 
     In some embodiments, a user can input an identification tag, such as, for example, a PIN, a name, a signature, or a code (e.g., a barcode in a NFC, QR, or other format) that can be stored or transmitted. Once one or more IDs have been entered into a wheel chock system, there can be one or more levels of authorized use by the one or more IDs. For example, there can be one or more of the stored IDs authorized to operate the loading dock including loading dock operations that can be interlocked by a wheel chock system, such as, for example, the door leveler or door opener functions. 
     It was realized that in some loading dock situations, yet another or different level of safety review can be used or is needed to ensure proper chock placement against the tire of a truck or trailer wheel. A camera can be mounted in or near the outside light box (e.g., in a typical camera weather resistant housing), or inside a building or loading dock where there is a view of the outside loading dock and the tire of a truck or trailer wheel, such as through a window or camera view port. The camera can be used to confirm that the chock has been placed properly. The camera can send an image by any suitable digital or analog means to a wheel chock system at the loading dock. In some embodiments, where there is a local wheel chock system display (typically a LCD display), the wheel/chock image can display directly on the local display for the operator of the loading dock door to visually approve the wheel chock placement before operating the loading dock door and door leveler. In wireless embodiments, the image can also be sent out wirelessly (e.g., over a network) for additional review by another person such as a supervisor to review. In some embodiments, the image from the camera can be sent via a RS-232 converter to the wireless module which then sends the image data from the Wi-Fi module to the network. 
     It is contemplated that in some embodiments, an image recognition process running on a processor of the controller or on another computer can be used to automatically indicate if the chock is properly and safely positioned against the tire of the truck or trailer wheel based on the image of the truck or trailer wheel and the chock. 
     It is contemplated that an image recognition process can be adapted to automatically detect proper chock placement, such as, for example, to detect when a chock is making proper contact with a truck or trailer tire. Any suitable feature of an image of the tire and/or chock can be used. For example, it is contemplated that taking into account camera viewing angle and camera distance from the chock and tire, it can be possible to program a process that can outline the tire and chock and determine the relationships between the outline of the tire and an outline of the chock, and to calculate if the chock is in contact with the tire. For example, the process can consider dimensions such as the spacing between the edge of the chock and the edge of the tire at one or more points along the tire and/or along a surface of the wheel chock. In some embodiments, there can also be motion detection process where if the tire is detected to have any motion, the routine assumes the chock is not correctly preventing tire movement and sounds an alarm and/or activates a loading dock equipment interlock. There can be a threshold of motion detection, where for example, a strong wind might cause some limited trailer rocking motion. There can also be chock placement detection based an absence of a chock in the image, where, for example, when properly placed, the chock is mostly or entirely obscured by the tire. Any suitable image recognition parameters can be used for an image recognition process to find the tire and/or chock in an image, such as to identify a boundary line or outline of the tire and/or chock. For example, the image recognition routine can use parameters, such as, for example, colors, shapes, or any other suitable features of the truck or trailer wheel and/or the wheel chock. Objects can be intentionally color coded or marked with position or boundary marks (human eye visible or not) that can show in the image. For example, in some embodiments, the chock handle shaft is colored yellow and an unfinished chock can appear to be a metallic grey on a color image of the wheel chock assembly. 
       FIG. 9  depicts a simplified overhead view of a properly chocked trailer tire, and one possible location for an outside loading dock camera  68  with a wide enough field of view to view the tire and/or chock. The camera  68  can be mounted in any suitable position to view the truck or trailer wheel  60  and the wheel chock  40 . The camera  68  can also be more directly aimed at an angle towards the expected location of the truck or trailer tire to be chocked. It is unimportant whether the camera  68  is mounted below, near, or above the expected tire/chock location as long as it can view the chocked truck or trailer tire.  FIGS. 10 and 11  depict a simplified overhead illustration of an incorrectly placed wheel chock  40 . All three situations of  FIGS. 9-10  can be viewed and interpreted by either by a person viewing the image on a display  72  at the loading dock, persons at one or more remote locations, and/or by an image recognition process adapted to identify wheel chock placement. While ideally the camera is fixed-mounted to avoid the need for operator intervention, the camera can also be mounted on a remote controlled positioning mount. Such a mount can allow a local or remote operator to view other parts of the loading dock. Also, it is contemplated that in some embodiments, an image recognition process as described hereinabove could also move the camera (e.g., fine tune the camera position) to find the wheel and/or the chock if one or both are not already in the image. 
     A software, firmware, and/or hardware signal and/or contact operation derived from the result of image recognition of safe chock placement can be used to interlock loading dock operations such as opening the loading dock door or operating the loading dock leveler. The result of such image processing of the wheel and chock image can be any suitable wheel chock placement safe/unsafe indication and/or any suitable interlocking functions. For example, there can be an interlock programmed into the controller code (e.g. controller firmware or software) to prevent certain loading dock operations by software control based on the image processing of the image of the wheel and chock. There can also be any suitable digital indication of proper chock placement based on the image processing of the image of the wheel and chock, such as, for example a digital “0” or “1” bit in data which can also be translated to an electrical level and/or a solid state switch status and/or an electrical contact operation (e.g. for hardware interlock purposes, such as, for example, to interlock AC power to a particular device such as a door motor and/or the leveler motor). 
     In some embodiments, a LCD panel, such as, for example a LCD display on the inside control panel and light box (not shown in the figures) can provide persons near the loading dock within the building truck chocking information from the wheel chock system, such as an image from an outside camera pointed in the vicinity of the rear trailer wheels and chock. 
     For example, a truck driver deems it unnecessary to properly chock the truck. The driver cheats the chock sensor such as by intentionally placing an item, such as a wallet, over the sensor aperture in the chock. Or, the chock may have been improperly placed under the tire (well enough to trigger the sensor, however unfortunately not well enough to be deemed proper chock placement) by an otherwise well intentioned, but hurried driver. A person at the loading dock viewing the wheel and chock, such as via a LCD display or through the Wi-Fi system on a mobile device can see that the wheel chock has not be properly placed for safe loading dock operation. In the case of a local loading dock operator, the operator refuses to proceed with operation of the loading dock based on the improper or unsafe placement of the wheel chock. In the case of a supervisor viewing the image on a mobile device or on a remote computer, in some embodiments, the supervisor can send a signal to freeze (e.g., by interlocking one or more loading dock electrical components) the operation of the loading dock, such as for example by an application running on the mobile device or remote computer. In other cases, the supervisor can order a halt to loading dock operations by intercom, by walking over to the loading dock, or by calling the operator of the loading dock, or by sending a message which is displayed on the local LCD. 
     It is contemplated that such supervisory functions can also be accomplished by computer image processing of the image of the wheel and chock. In such an automated supervisory role, the result of the image recognition of an improper chock placement can inhibit or interlock loading dock operations until the image shows a correct chock placement. In such automated image processing installations, there can also be alarms sent by the wireless module, such as by Wi-Fi, from the wheel chock system notifying others by network connection that loading dock operation was attempted with an improper wheel chock placement. 
     It will be appreciated by those skilled in the art that other notification means can also be used. For example, it is contemplated that a Wi-Fi wheel chock system can also send text messages, send email notifications, and/or make phone calls to announce an alarm condition. 
     As noted above, the wireless module can be mounted to the wheel chock assembly instead of the inside control panel, and communicate wheel chock system information wirelessly to the controller. Accordingly, one embodiment of the present invention includes wireless transmission of wheel chock sensor data from the chock to the controller at the loading dock. Referring to  FIG. 12 , wherein like numerals indicate like parts from  FIGS. 1-3 , depicted is an exemplary wireless wheel chock system  1210  configuration in which the wireless module  1270  is operatively coupled  126  to the wheel chock assembly  14  (also shown in  FIG. 1 ). The wireless module  1270  communicates wheel chock system information via any suitable form of wireless communication  128  such as, for example, any suitable type of radio frequency (RF) wireless communication. The wireless module  1270  can include a transmitter portion  130  located at the wheel chock assembly  14 , and a receiver portion  132  operatively coupled to the controller  20 . Any suitable computer  12110  connected to network  12108 , such as a local area network or the Internet, can receive wheel chock system information  12122  from Wi-Fi module  1270 . 
       FIG. 13  depicts a wheel chock assembly  14  with a wireless module according to one embodiment of the invention. As illustrated, the wheel chock assembly  14  can include a wheel chock  40  having an upward-curving tire contact surface  134  facing the wheel to be chocked. The tire contact surface includes a convex surface  136  having a radius extending generally upwards from the ground surface. The wheel  60  ( FIG. 2 ) engages convex surface  136  rather than a concave surface as found in conventional wheel chocks (see, for example, the chock in  FIG. 2 ). In one example, the radius of curvature of the convex surface  136  may be between 11.0 inches and 14.0 inches, preferably 12.25 inches. In the illustrated embodiment, the tire contact surface further includes a concave extension surface  138  joined to an upper end  140  of the convex surface  136 . The concave extension surface  138  acts as a barrier to prevent a vehicle from accidentally driving over the wheel chock  40  without the chock having been removed. In one example, the radius of curvature for the concave extension surface  138  may be between 2.0 inches and 3.0 inches, preferably 2.43 inches. The upper end  140  may be the geometrical inflection point where the tire contact surface transitions from convex to concave. In one example, the upper end  140  of the convex surface  136  may be positioned at an angle in a range between 20 and 30 degrees from horizontal. The tire contact surface may be fabricated from ¼-inch aluminum plate having a width of about 8.0 inches. In other embodiments of the invention, the tire contact surface does not include the concave extension surface  138 . In still other embodiments, the tire contact surface may be other geometries besides convex. For example, the tire contact surface may be concave as shown in  FIG. 2 , or may be flat. 
     The wheel chock  40  further includes front, middle, and rear support elements  142 A,  142 B, and  142 C, respectively, for transferring tire loading from the contact surface to the ground. In the disclosed embodiment, the support element  142  includes three web support plates welded to the tire contact surface. Each web support plate  142  may be formed from ¼ inch aluminum having a width approximately equal to the tire contact surface. 
     The wheel chock  40  may further include a ground engaging base portion  144  coupled to the support element  142 . The base portion  144  provides structural support to the wheel chock  40  and transfers the loads to the ground. In one embodiment, the base portion  144  may be formed from a single flat plate that contacts the ground. In other embodiments, the base portion  144  may include two or more plate sections welded or otherwise joined to the web support plates. The base plate may be formed from ¼ inch aluminum having a width approximately equal to the tire contact surface (e.g., 8 inches). The front section of the base plate  144  may be welded at one end to the tire contact surface and at the other end to web support plate  142 A. The mid-section of the base plate  144  may be welded to the intermediate web support plate  142 B. The rear section of the base plate  144  may be welded to the intermediate and aft web support plates  142 B,  142 C. 
     In one embodiment of the invention, the base portion  144  can include at least one projection  146  to concentrate the load path to the ground surface. In doing so, the projection(s)  146  push into the ground and greatly increase the horizontal resistance to movement. In the illustrated example, the projections  146  are provided by the edges of the tire contact surface and the web support plates  142 . The projections  146  may be disposed at angles relative to horizontal that further increase the horizontal resistance to movement. For example, web support plates  142  may be at an angle between 45 degrees and 60 degrees. 
       FIG. 14  depicts a left-side view of the wheel chock assembly  14 , and  FIG. 15  depicts the same left-side view, rotated to a perspective view, with the chock body removed for clarity (e.g., tire contact surface  134 , front and rear support elements  142 A,  142 C, and base portion  144  removed). The wheel chock system  10  may further include a sensor  44  ( FIG. 13 ) for detecting the presence of the wheel  60 . The output of sensor  44  may serve as logical input for the dock light warning system  16 ,  18  ( FIG. 1 ) to assure the presence of the wheel chock  40  against the wheel when a truck is backed into position adjacent a loading dock. 
     In one possible implementation, the convex surface  136  of the chock defines an aperture  148  ( FIG. 13 ) and the sensor  44  is adapted to measure the presence of the truck tire through the aperture. In the illustrated embodiment, the sensor  44  is a lever arm  150  configured to pivot about an axis  152  that extends transverse relative to the chock  40 . The lever arm  150  may be predominantly L-shaped, with a forward leg  154  extending through a cutout  156  in the middle support element  142 B, and a rearward leg  158  forming a portion of a trigger mechanism, as will be explained below. The tip of the forward leg  154  may include a contact element  160  to protect the integrity of the lever arm  150 . The pivot axis  152  about which the lever arm  150  rotates can be defined by a shoulder bolt  162 . Although hidden from view, a rotary thrust bearing may be disposed about the shoulder bolt  162  to permit free rotation of the lever arm  150  and to absorb side loads caused by the tire  60 . 
     The lever arm  150  may be spring-biased about the axis  152  to ensure the opposing forward leg  154  of the lever arm protrudes through the chock surface aperture  148  and is ‘proud’ relative to the convex surface  136  of the chock. With reference to  FIG. 14  and  FIG. 15 , a lever arm torsion spring  164  can be wound (i.e., pre-loaded) about an arm spring spacer  166  with one leg  168  constrained to a slot  170  in the chock middle support plate  142 B, and the opposing leg  172  held into a groove  174  on the upper surface of the lever arm  150 . As best seen in  FIG. 16 , the pre-loaded torsion spring  164  will tend to rotate the lever arm  150  about the axis  152  in a clockwise direction, such that the lever arm rotates up through the aperture  148  in the convex surface  136  of the chock. The lever arm  150  can be configured to butt up against the upper surface of the middle support cutout  156 , which effectively stops further upward motion. Contact area “C” in  FIG. 17  illustrates an exemplary contact location that prevents the lever arm  150  from further clockwise (i.e., upward) movement. Accordingly, the preload in the lever arm torsion spring  164  results in a preload force F 164  on the lever arm  150 , which must be overcome for the lever arm to move downward. 
     In one example, the torsion spring  164  can impart a preload force F 164  of approximately 30 pounds on the lever arm  150 . Thus, the lever arm is unlikely to be depressed unless an actual tire is on the chock. 
     The contact element  160  may be secured to the forward leg  154  of the lever arm  150 . The contact element  160  may be the only hardware directly in contact with the truck tire, and therefore may be configured to better withstand the harsh, abrasive conditions likely to be encountered. In one embodiment, the contact element  160  can be a free-spinning wheel assembly having a hardened elastomer tire. In one example, the tire  160  may be formed of urethane having a hardness ranging from 82 A to 101 A. 
     Turning now to  FIGS. 16-18 , shown is wireless module  1270  configured to transmit sensor data to the controller  20  at the loading dock  12  ( FIG. 1 ). In one embodiment of the invention, the wireless module  1270  can include a position switch  176 . The wheel chock system  10  can be configured such that the rotation of the lever arm  150  (due to the presence of a properly chocked tire) causes the rearward leg  158  to activate the position switch  176 , which may then cause the wireless module  1270  to transmit data to a receiver  132  at the loading dock  12  ( FIG. 1 ) indicating the wheel chock  40  is properly positioned against a truck tire. The receiver  132  can relay the chock data to the controller  20 , which can command the operation of the loading dock safety interlocks  98 , as explained above. The receiver  132  may be a stand-alone unit, or may be integrated with the outside light box  16 , the inside control panel  18 , or the controller  20 . The wheel chock system  10  can further be configured such that, when the wheel chock  40  is removed from the tire  60 , the lever arm  150  rotates in the opposite direction (due to the preload in the lever arm torsion spring  164 ), the rearward leg  158  deactivates the position switch  176 , causing the wireless module  1270  to transmit new status data to the receiver  132  at the loading dock  12 . 
     In the illustrated example, the position switch  176  comprises a spring-loaded, depressible plunger  178 . The wheel chock system  10  can be configured such that the rotation of the lever arm  150  causes the rearward leg  158  to depress the plunger  178 , thereby causing the wireless module to transmit data to the receiver  132 . When the wheel chock  40  is removed from the wheel  60 , rotation of the lever arm  150  in the opposite direction causes the rearward leg  158  to back off the spring-loaded plunger  178 , the plunger snaps back to its original position, and the wireless module  1270  may transmit new status data to the receiver  132  at the loading dock  12 . 
     Wireless module  1270  requires an electrical power source for activation and usage of the circuits to transmit the chock sensor data to the receiver  132 . In some embodiments, the power source may be a hard line connection, such as cable  34  shown in  FIG. 2 . However, the cable  34  requires special additional hardware, such as cable pole  32 , to minimize entanglements and interference with loading dock operations. In other embodiments, the power source may comprise a battery, such as a primary cell (i.e., non-rechargeable) or a secondary cell (i.e., rechargeable). However, both battery types have drawbacks. Non-rechargeable batteries frequently need replacement, which requires extra manpower and an exacting maintenance schedule to prevent a discharged battery from interrupting loading dock operations. Rechargeable batteries offer a somewhat better alternative, but still require a charging port in proximity to the chock, which is usually outdoors in the environmental elements. An external charging port therefore requires adequate environmental protection against rain, snow, etc. 
     In one embodiment of the present invention, these deficiencies are overcome through use of an energy harvesting mechanism to provide an electrical power source for the wireless module  1270 . The electrical power required for the transmission can be provided by an electrodynamic energy generator that is activated when the wheel chock properly engages the truck wheel. In one example, the position switch  176  may include an induction generator having an electrically conductive coil core in abutment with a spring-loaded, moveable magnet group. The switch can be configured to form a closed annular magnetic flux through the coil core and magnet group when the magnet group is positioned in a first, at-rest state. Depressing the plunger  178  can release the spring elements in a ‘snap action,’ causing the magnet group to rapidly accelerate to a second, at-rest position. The second position is still in abutment with the coil core, but at a different location. The second position can be configured to reverse the direction of the closed annular magnetic flux. As such, the rapid directional shift in magnetic flux (from the first position to the second position) can induce a voltage in the coil core, which voltage can then be utilized to power the components in the wireless module  1270  and transmit data to the receiver  132  at the loading dock  12 . In similar fashion, when the plunger  178  is released, a second spring element can snap the magnet group from the second position back to the first position, once again inducing a voltage in the coil as the magnetic flux changes direction in the coil core. 
     In one embodiment of the invention, the induced voltage can be used as a supply voltage to power RF electronics in the wireless module  1270 . The RF electronics can transmit a radio protocol with message data via an antenna  180  to the receiver  132  at the loading dock. In one example, the transmission is carried out at a frequency of 868.3 MHz or 915 MHz. Exemplary protocols include KNX-RF, ZigBee, Bluetooth Low Energy, or customer-defined proprietary protocols. 
     The plunger  178  typically travels a short distance, approximately 0.5 inches or less, to release the spring elements in a ‘snap action.’ The short range of travel presents a challenge for the lever arm design, because the movement of the arm follows a one-to-one correspondence with movement of the plunger  178 . That is, with nothing more, the lever arm  150  must be designed to travel no more than the plunger travel. Otherwise, one concern with this configuration is that the lever arm  150  could over-travel and crush the position switch  176  and plunger  178 . A design that allowed the contact element  160  to protrude only 0.5 inches proved difficult. 
     One solution to this problem was to alter the 1:1 ratio in favor of the lever arm, such that larger ranges of motion at the forward leg  154  of the lever arm  150  translated to smaller ranges of motion at the plunger  178 . Such configurations could involve gears, cams, or springs and the like. 
     Another solution, which is illustrated and described herein, adds a safeguard mechanism to prevent over-travel against the plunger  178  and body of the position switch  176 . Embodiments of the present invention include a trigger arm  182  operating in concert with the lever arm  150 . The motion of the trigger arm  182  contacts and depresses the plunger  178 , but its range of motion is impeded thereafter. Meanwhile, the motion of the lever arm  150  may continue unimpeded. 
     Referring generally to  FIGS. 16-18 , and in particular to  FIG. 18 , the trigger arm  182  can be configured to pivot about the same axis  152  as the lever arm  150 . In the illustrated example, the trigger arm  182  mounts to the shoulder bolt  162 . The trigger arm  182  can be spring-biased towards the plunger  178  to ensure positive contact when the plunger is depressed. In one embodiment, a trigger torsion spring  184  can be wound (i.e., pre-loaded) about a trigger spacer  186 . A first leg  188  of the trigger torsion spring  184  can be constrained to a slot  190  in the middle support plate  142 B, and the opposing leg  192  of the torsion spring can be retained in a groove  194  on the upper surface of the trigger arm  182 . 
     As best seen in  FIG. 16 , wherein the end face  158  of the lever arm  150  is shaded and the trigger arm  182  is cross-hatched, the pre-loaded trigger torsion spring  184  will tend to rotate the trigger arm  182  about the axis  152  in a counter-clockwise direction, towards the plunger  178 . As illustrated in  FIG. 16 , the trigger torsion spring  184 , when pre-loaded, causes the trigger arm  182  to rotate in a counter-clockwise direction until it makes contact with and is stopped by the underside surface of the lever arm end  158 . Accordingly, the preload in the trigger torsion spring  184  results in a preload force F 184  on the trigger arm  182  (see arrows), which force is in opposing relation to spring force F 164 . In one embodiment, the spring force F 164  is greater than spring force F 184 , so the lever arm  150  effectively impedes further motion of the lesser-force trigger arm  182 . In one example, the lever torsion spring  164  can impart a preload force F 164  of approximately 30 pounds on the lever arm  150 , and the trigger torsion spring  184  can impart a preload force F 184  of approximately 15 pounds on the trigger arm  182 . Although there appears to exist a net positive force against the trigger arm, such that the lever arm would push the trigger arm backwards (i.e., clockwise in  FIG. 16 ) the lever arm pre-load force is actually counteracted at contact surface C ( FIG. 17 ), and the lever arm is constrained from rotating any further in the clockwise direction. 
     In the above example embodiment, the pre-load values of the torsion springs establish a first position for the wheel chock assembly  14 , in which the lever arm  150  and/or contact element  160  can be retained in a position raised above the tire contact surface  134 , and the trigger arm  182  can be retained in a position away from the plunger  178  on the position switch  176 . No elements of the chock assembly  14  are capable of movement until a vehicle tire bears against the lever arm. As will be explained below, a second, intermediate position can be established when the lever arm  150  moves enough to permit the trigger arm  182  to depress the position switch  176 , at which point the trigger arm can be restrained from further movement. The lever arm  150  and/or contact element  160  can still be protrude above the chock tire contact surface at the intermediate position. Finally, a third, max-travel position can be established wherein the lever arm  150  and/or contact element  160  can be fully pushed down into the chock body, flush or below the tire contact surface  134 . 
       FIGS. 19 and 20  illustrate the wheel chock assembly  14  in the first position, which is essentially the same view as  FIG. 16 , except the torsions springs have been removed for clarity. The contact element portion  160  of the lever arm  150  is retained in a position protruding above the tire contact surface  134  a distance D 1 . The safeguard trigger arm  182  is biased against the rearward leg  158  of the lever arm  150 , and is spaced away slightly from the plunger  178  of the position switch  176 . Also illustrated is an end view of stiffener bolt  196 , which can be used to strengthen the frame of the wheel chock  40 . A perspective view of the stiffener bolt  196  is illustrated in  FIG. 13 . 
       FIGS. 21 and 22  illustrate the wheel chock assembly  14  in the intermediate position. The contact element portion  160  of the lever arm  150  has been pushed down by the vehicle tire such that it is raised above the tire contact surface  134  a distance D int , so the lever arm  150  has not yet achieved full travel. The safeguard trigger arm  182 , being biased towards a counter-clockwise rotation, remains abutted against and therefore follows the underside surface of the lever arm end  158  as the lever arm rotates counter-clockwise due to the action of the vehicle wheel. At the illustrated intermediate position, the trigger arm  182  has depressed the position switch plunger  178 , which causes the wireless module  1270  to send a message to the controller  20  at the loading dock. At the same time, the tip of the trigger arm  182  encounters the stiffener bolt  196 , which is rigidly fixed to the wheel chock housing. Therefore, once the trigger arm  182  depresses the plunger  178 , it is constrained by the stiffener bolt  196  from rotating any further in the counterclockwise direction. The constraint prevents the plunger  178  and position switch  176  from being crushed by the trigger arm. Note that the trigger torsion spring  184  preload force F 184  biases the trigger arm against the stiffener bolt  196  to hold it in place. 
     Even though the motion of the safeguard trigger arm  182  is impeded at the intermediate position, the lever arm  150  may continue its movement as the vehicle wheel pushes the contact element  160  into the chock housing.  FIGS. 23 and 24  illustrate the wheel chock assembly  14  in the maximum travel position. The contact element portion  160  of the lever arm  150  has been pushed down flush or below the tire contact surface  134 , such that D max  is equal to zero. Referring to  FIG. 24 , note how the full travel of the contact element  160  caused the rearward leg  158  of the lever arm to move a distance Gap max  away from the trigger arm  182 , because the trigger arm is constrained from further rotation by the stiffener bolt  196 . 
     As discussed above, when the wheel  60  pushes down on the contact element  160  to a height of D int , the trigger arm  182  depresses the position switch plunger  178  and the wireless module  1270  sends a message to the controller  20  at the loading dock that the wheel is chocked. Conversely, when the chock  14  is removed from the wheel, the contact element  160  raises up above the tire contact surface  134  and, and upon reaching height D int , the position switch plunger  178  is released, returning to the position shown in  FIGS. 19-20 , which causes the wireless module  1270  to send a message to the controller  20  at the loading dock that the chock is removed. 
     One problem unique to the loading dock industry are the dynamic forces on the chock during trailer loading and unloading operations. Very often the trailer jumps up and down as fork lifts and pallets are loaded or unloaded from the trailer. As a result, the tire on the chock may also bounce up and down or otherwise move about. This dynamic movement may be on the order of an inch or two, but the movement can be enough to exceed height D int , which would also pivot the lever arm  150  and back off the plunger  178  enough to snap it back to the uncompressed position. Such action would cause a false signal to be transmitted to the loading dock that the trailer was no longer chocked. 
     In one embodiment of the invention, this ‘false signal’ problem can be solved by applying a biased dead band to the intermediate height D int , such that the point of engagement of the switch is not the same as the point of disengagement. In other words, the ‘throw’ of the position switch plunger  178  may be different for signaling chocking versus unchocking. 
     Referring now to  FIG. 25 , shown are various positions for a plunger  178  on a position switch according to one embodiment of the present invention.  FIG. 25A  depicts the plunger  178  in the first position, fully extended a distance D 1  from its housing  198 , prior to a wheel engaging the chock.  FIG. 25B  depicts the plunger  178  in the intermediate position, at the moment the plunger is compressed far enough into the housing  198  to engage the switch. The difference between the fully extended length D 1  and the intermediate extended length D engage  when the switch is activated is the ‘throw distance,’ or (D 1 −D engage ). FIG. 25 C illustrates the plunger  178  in the intermediate position, at the moment the plunger is extended far enough from the housing  198  to disengage the switch. The difference (D disengage −D engage ) between the intermediate point of engagement and the intermediate point of disengagement is the dead band DB. The extra travel distance before disengaging compensates for the dynamic motion of the trailer. 
     In the illustrated embodiment, the dead band is provided by a mechanical means. However, it is contemplated the dead band could also be provided electronically. 
     While the network of loading dock controllers has been described hereinabove with respect to embodiments of wheel chock systems, there can also be loading dock safety systems which similarly incorporate an outside light box, and inside light box, and a controller which can be used independently of a wheel chock or wheel chock assembly (e.g., without a wheel chock by design, or where there is a broken or severed wheel chock assembly). Such loading dock safety systems can provides safety signaling of all of the signaling types described hereinabove (e.g., lights, audio alarms, and network based messaging and alarms) based on other loading dock parameters. For example, such a safety system might use a subset of the safety related parameters used by a wheel chock system, including loading dock door position and/or movement, safety chain across the loading dock opening in place or open, etc. There can also be additional sensors of any suitable type. For example, even in the absence of a smart chock assembly, there can still be a camera with a view of a truck or trailer wheel that can manually (e.g., by operator observation) or automatically (e.g., by controller or any other suitable computer) image recognition identify the presence of a truck or trailer wheel or tire at the loading dock. Or, where a conventional (not smart) wheel chock is present for use by a truck driver arriving at the loading dock, any of the imaging methods described hereinabove can be used. Any such safety systems can be networked using any of the techniques described hereinabove with respect to wheel chock embodiments. 
     A microcomputer is understood to include a microcontroller, a microprocessor, or any suitable device configured to perform the functions of a microcomputer, such as, for example, an application specific IC (ASIC) or field programmable gate array (FPGA). The controller functions can also be performed by any suitable computer, such as, for example by a notebook, desktop, or netbook computer. 
     Any suitable computer device can interact with a wireless wheel chock system. For example, a Wi-Fi wireless wheel chock system can interact with any suitable network connected computer or mobile device, such as, for example, a desktop computer, notebook computer, a netbook computer, a laptop computer, a tablet computer, or a smart phone. A standard telephone or cell phone can suffice the case of automated calls alarms from a wheel chock system. 
     Firmware or software running on the microcomputer of the controller or on another computer (e.g. image processing or alarm indications) is typically supplied on a computer readable non-transitory storage medium. A computer readable non-transitory storage medium as non-transitory data storage includes any data stored on any suitable media in a non-fleeting manner. Such data storage includes any suitable computer readable non-transitory storage medium, including, but not limited to hard drives, non-volatile RAM, SSD devices, CDs, DVDs, etc. 
     While the present invention has been described with reference to a number of specific embodiments, it will be understood that the true spirit and scope of the invention should be determined only with respect to claims that can be supported by the present specification. Further, while in numerous cases herein wherein systems and apparatuses and methods are described as having a certain number of elements it will be understood that such systems, apparatuses and methods can be practiced with fewer than the mentioned certain number of elements. Also, while a number of particular embodiments have been described, it will be understood that features and aspects that have been described with reference to each particular embodiment can be used with each remaining particularly described embodiment. For example, many illustrated embodiments herein disclosed a convex wheel chock. However, the embodiments could also be used with a conventional concave wheel chock.