Patent Publication Number: US-8978276-B2

Title: Safety systems for wireless control for snow plows

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/683,944, entitled “Safety Systems for Wireless Control for Snowplows” which was filed on Aug. 16, 2012, the entire disclosure of which is hereby incorporated by reference herein. Additionally, this application is related to U.S. patent application Ser. No. 13/778,357, entitled “Wireless Snow Plow Control” and filed concurrently herewith, the entire disclosure of which is hereby incorporated by reference herein. 
    
    
     FIELD OF THE DISCLOSURE 
     This disclosure relates to safety systems, and in particular, to safety systems for wireless snowplow controllers. 
     BACKGROUND 
     Typical snowplow control systems include a controller device within the cab of a vehicle, a wiring harness connecting the controller to the vehicle&#39;s electrical system and a plug plus one or more harnesses to connect the vehicle to a snowplow. The plug between the vehicle and snowplow harnesses is susceptible to weather and environmental conditions (e.g., snow, water, road salt) and is a common failure point in snowplow control systems. Replacing the wired controller with a wireless controller would eliminate this failure point. Additionally, by replacing the wired controller with a wireless controller, the wiring harness between the vehicle and plow may be eliminated, as the wiring between the vehicle and the plow may be reduced to only a power cable and a ground cable, as control signals from the controller are transmitted wirelessly. The use of a wireless controller would also allow the users increased flexibility in controlling the snowplow. For example, with a wireless controller, snowplow users may have the option of controlling the snowplow remotely while avoiding a common source of control system failure. 
     Wireless controllers, however, introduce their own set of issues, especially with respect to user safety. Because wireless controllers are free to operate outside the vehicle cab, the controllers may be especially prone to unintended use. 
     Wireless controllers may also be prone to accidental activation if a user does not realize that the controller is configured to operate the snowplow wirelessly. In this scenario, even a well-intentioned user may accidentally actuate the snowplow if he manipulates the controller within its wireless activation range. 
     Wireless controllers are also more susceptible to power management issues than wired controllers. More specifically, wireless controllers generally rely on internal batteries for power. Because of this, wireless controllers typically can only remain powered for a limited time before their batteries run out of energy. If a controller battery dies while a user is operating the snowplow, this may also lead to safety hazards, as it may not be possible to change the position of the snowplow (such as from a position that obscures the driver&#39;s view or from a position in contact with a road surface), as the controller will not function with a dead battery. In contrast, wired controllers often can draw power from and/or recharge themselves when plugged into another device, such as, for example, a snowplow or vehicle. 
     Without a proper safety system in place, wireless snowplow controllers may cause a number of safety hazards that may outweigh their benefits and limit their usefulness. While systems for limiting the range of wireless controllers have been implemented, they are flawed. For example, U.S. Pat. No. 6,112,139 to Schubert et al. describes a method to limit the spatial operating range of a wireless controller by configuring receiver circuitry, this method is flawed as, among other things, it still allows more than one controller within the operating range of the receiver to potentially control the snowplow. 
     SUMMARY 
     A system includes a vehicle, a snowplow, a wireless controller and a tether in communication with a power supply. The controller wirelessly sends one or more control signals to one or more control modules coupled to the vehicle and/or the snowplow. The control signals may be used to control operation of the snowplow. The controller may be configured such that it is only able to control the snowplow when it is connected, via the tether, to a power supply coupled to the vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an environmental view illustrating a truck with a snowplow and a wireless snowplow controller, and  FIG. 1A  is an enlarged view of the cab area of the truck, denoted by the broken-lined circle  1 A of  FIG. 1 , illustrating the wireless snowplow controller tethered to the interior of the cab of the truck; 
         FIG. 2  depicts a wireless snowplow controller according to the present disclosure; and 
         FIG. 3  is a block diagram of a controller-power source safety configuration according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A system of the present disclosure provides safety features for a wireless snowplow controller. The system may be redundant (i.e., there may be more than one safety option for the same controller) or may incorporate a single safety feature. Additionally, one or more safety features of the safety system may be turned on or off by a user. 
     Generally, the described system may be used to provide safety features for a wireless snowplow controller. The features may be used, for example, to prevent unauthorized or unintentional snowplow activation. 
     The snowplow control system may include a wireless controller and one or more control modules (e.g., a vehicle control module (VCM), and a plow control module (PCM)). The VCM may be installed in the engine compartment of a vehicle and may communicate with the PCM. The PCM may be self-contained on the snowplow. 
     The wireless controller may be physically tethered to the cab of a vehicle. The tether may be an electrical cable having a length such that the wireless controller cannot be taken outside the cab while the tether is still attached. The tether may be electrically connected to a power supply within the cab, such as a 12V socket provided as a standard feature of the vehicle. Additionally, the tether may be electrically connected to one or more batteries within a housing of the controller and used to power the controller, in such a manner as to charge the controller&#39;s battery or batteries while the controller is physically connected to the cab. Although the controller is physically and electrically connected to the cab via the tether, control signals between the controller and the PCM and the VCM may still be transmitted and received wirelessly (e.g., via RF, IR, etc.), and the controller may be powered independently of the tether for purposes of fulfilling its wireless transmissions. 
     Optionally, the controller may be configured such that it can control the snowplow even while the controller is not tethered to the vehicle cab. The configuration may be implemented via hardware, software, or a combination of hardware and software. As an additional safety feature, a user may be required to enter a password or code before the tethering requirement is overridden and the controller is allowed to perform control functions wirelessly. 
     The tethering feature may be combined with other safety features. For example, an infra-red system may be implemented such that the controller will not function if an infra-red signal between the controller and a vehicle sensor is lost. This infra-red system effectively limits the operating range of the wireless controller. Additionally, the sensor may be in communication with one or more sensors (e.g., ultrasonic or weight sensors) that can detect when a person is located within the cab of the vehicle. If the one or more sensors do not detect a person, the controller may not function. Additionally, an RF-proximity configuration may be implemented such that the controller will only function if it is closer to the vehicle than it is to the plow itself. 
     The described functionality can be implemented in a combination of hardware, software, and/or firmware on a wireless controller device and a tether. 
     Generally speaking, the systems and techniques of the present disclosure can be applied as part of a snowplow control system but may be used in the context of other vehicles or large controllable devices. 
       FIG. 1  is an environmental view of a truck equipped with a snowplow and a snowplow controller. The wireless control system  100  may include a wireless snowplow controller  110  (also referred to herein as a “controller”), a tether  120  (see  FIG. 1A ), a vehicle  130 , and a snowplow  140 . The controller  110  is for operator use and may typically be disposed within a vehicle cab and/or within an operator&#39;s reach while he is operating the vehicle. The snowplow  140  may be coupled to one or more modules that are in wireless communicative connection with the controller  110 . More specifically, the module or modules may communicate with the snowplow  140  using wireless communications, packets, messages or signals from the controller  110  that correspond to one or more commands relating to one or more desired operations of the snowplow  140 . 
     The commands may be used to activate or deactivate, and/or control various operations of elements of the snowplow  140 . For example, the commands may activate and/or deactivate the appropriate snowplow valve or valves to perform blade operations (e.g., angle, raise, lower, or vee), hitch or connection operations (e.g., attach, detach) and/or pump operations (e.g., start, stop). Additionally, the commands may be used to operate or more plow lights mounted on the snowplow  140 , such as a plow headlight, a plow turn signal, a plow reverse light, or a plow daytime running lamp. A PCM may be electrically connected (e.g., via wired, wireless or both wired and wireless connections) to at least one of a plow headlight, a plow turn signal, or a plow daytime running lamp. The PCM may provide signals to the one or more plow lights for operation (e.g., on, off, blinking, high or low beam, tilt, move). 
       FIG. 2  is a block diagram detailing an exemplary embodiment of the wireless snowplow controller  110  according to the present disclosure. Controller  110  may include override circuitry  210 , communication circuitry  220 , battery  230  (which may include one or more batteries of either a single-use or, preferably, a rechargeable nature) and connector  240 . The controller  110  may also include one or more user controls  250  that correspond to various desired operations of the snowplow  140 . The one or more user controls  250  may be of any configuration or format, such as, for example, a joystick, toggle, push-button, dial, lever, touch screen, voice-activated control, and/or any other suitable user control. At least some of the one or more user controls  250  may correspond to desired snowplow operations, such as raise, lower, angle right, angle left, attach, detach, tilt, scoop, vee, or straight. Controller  110  may optionally be connected by tether  120  (not shown in  FIG. 1 ) to an external power source such as a  12  volt power source or some other power source resident on the vehicle . While connected to the external power source, the controller  110 &#39;s battery  230  may be charged by the external source. Additionally, the external power source may serve to power the controller  110  while the external source and the controller  110  are connected via tether  120  (not shown). 
       FIG. 3  is a block diagram source safety configuration for a wireless snowplow controller according to the present disclosure. The safety configuration  300  may include controller  110 , tether  120  and voltage source  310 . As described above, controller  110  may include override circuitry  210 , communication circuitry  220 , battery  230 , connector  240 , and control circuitry  260 . Override circuitry  210 , communication circuitry  220 , battery  230 , connector  240 , and control circuitry  260  may be separate modules or may be combined and may interact with each other and/or with other software, hardware, and/or firmware. 
     As discussed above, controller  110  may be physically tethered to the cab of a vehicle. The tether  120  may be an electrically conductive cable having a length such that the controller cannot be removed from an interior of the cab while the tether is still attached. The tether  120  may be electrically connected to voltage source  310  Although the controller  110  is physically and electrically connected to the cab via the tether  120 , control signals between the controller  110  and the control module or modules may still be transmitted and received wirelessly (e.g., via RF, IR, etc.) using, for example, communication circuitry  330 . 
     More specifically, while tethered to the vehicle  130 , controller  110  may use communication circuitry  220  to transmit commands wirelessly to one or more module or modules that are coupled to the vehicle  130  and/or the snowplow  140 . Although the controller  110  is physically connected to the vehicle via tether  120 , the tether is not used to transmit control commands. Instead, the tether  120  may act as an effective switch. Through the use of control circuitry  260  and tether  120 , communication circuitry  220  may be “switched off” if controller  110  does not detect a connection to an external power supply via tether  120 . More specifically, tether  120  may be directly connected to control circuitry  260 , effectively “closing the loop” between control circuitry  260  and communication circuitry  220 . In certain implementations, if tether  120  is not directly connected to control circuit  260 , the electrical circuit between the components may not complete, effectively turning off communication circuitry  220 . Alternatively, even if there is an electrical connection between components in the absence of a tether connection, controller  110  may check for a tether connection before permitting the communication circuitry  220  to transmit signals. The check for the tether connection may be performed in a number of ways. For example, control circuitry  260  may be programmed and/or designed to detect different levels of current and/or voltage in controller  110  when the tether  120  is connected compared to when the tether is disconnected. Tether  120  may also be configured to transmit a signal to controller  110  when it is connected to an external power source. The signal may then be detected, for example, by control circuitry  260 . After the tether  120  is detected, communication circuitry  220  may then be permitted to transmit control signals. In certain implementations, controller  110  may include an analog channel input configured to monitor voltage on tether  120  and/or at connector  240 . The analog channel input may, for example, detect a change in voltage and/or an “open circuit” condition if tether  120  is not connected to an external power source. Upon detecting that tether  120  is not connected to an external power source, the controller  110  may instruct communication circuitry  220  not to wirelessly transmit commands. More specifically, the analog channel input may effectively cause another circuit to transmit an instruction signal or effectively “open the communication circuit” without the use of an instruction signal, preventing communication circuitry  220  from transmitting commands. 
     As discussed above, in certain implementations, communication circuitry  220  may be completely prevented from transmitting command signals if an external power supply connection is not detected, thereby preventing the wireless controller from actuating the snowplow  140  when not tethered to the external power supply via tether  120 . Alternatively, controller  110  may only be able to transmit low-power or unrecognizable signals to the one or more modules coupled to the vehicle  130  and/or the snowplow  140 , which may permit only limited functionality of the snowplow  140  (such as permitting only movement of wings of a Vee-blade snowplow, but not permitting raising and lowering of the snowplow). 
     In a preferred implementation, as described above, hardware and/or software on controller  110  will confirm that controller  230  is connected to an external power supply via tether  120  and/or that battery  230  is being charge. Alternatively, in certain implementations, a control module separate from controller  110  (e.g., a PCM or VCM) may confirm that battery  230  is being charged and that tether  120  is connected to both an external power supply and/or connector  240  before accepting control signals or implementing commands from controller  110 . If the control module detects that battery  230  is not being charged and/or tether  120  is not properly connected, the control module may send or cause a message to be sent to the controller indicating that it will not accept and/or implement commands until tether  120  is properly connected and/or battery  230  is being charged. 
     Because controller  110  may supply its own power (i.e., battery  230  may provide the power required for control operations), controller  110  may only require a minimal amount of power from vehicle  130 , as the vehicle may merely provide current to provide an electrical connection between the control circuitry  260  and communication circuitry  220 . Accordingly, control circuitry  260  may be designed such that it draws a limited amount of current compared to traditional wired controllers. This may be implemented, for example, through the use of current limiting circuitry (e.g., a fuse, a resistor configuration, a current limiting diode, a capacitor configuration) Compared to traditional wired controllers, which may draw significant power from the power supply (e.g., the vehicle) to power controller operations, through the use of current limiting circuitry associated with control circuitry  260 , controller  110  may be significantly less draining on the vehicle battery. While implementations in which voltage source  310  charges the battery  230  or another internal power source inside controller  110  may draw more power than implementations in which voltage source  310  does not charge the battery  230  or another power source, both implementations may still be energy efficient compared to traditional wired controllers. Alternatively, voltage source  310  may provide power to the controller  110 , allowing control circuitry  260  to communicate with one or more control modules. 
     While the controller  110  may be powered independently of the tether for purposes of fulfilling its wireless transmissions, in certain implementations, tether  120  may optionally supply power to controller  110 . Further, tether  120  may optionally charge or recharge the battery  230  while the controller  110  is physically connected to the cab. 
     As discussed above, controller  110  may be connected to an voltage source  310  via tether  120 . Voltage source  310  may, for example, be a 12 volt power source (e.g., a cigarette lighter or internal battery) or some other power source resident in the cab of the vehicle  130  (e.g., a USB device connector, an A/C outlet, a radio connector, a phone connector). Further, while connected to the external power source, the battery  230  or another internal power source inside controller  110  may be charged by voltage source  310 . Additionally, the voltage source  310  may serve to power the controller  110  while the external source and the controller  110  are connected via tether  120 . 
     Optionally, the controller  110  may be configured such that the controller  110  can control the snowplow  140  even while it is not tethered to the vehicle cab. The configuration may be implemented via hardware, software, or a combination of hardware and software. As an additional safety feature, a user may be required to enter a password or code before the tethering requirement is overridden and the controller  110  is allowed to perform control functions wirelessly. These elements may be implemented using override circuitry  210 . Override circuitry  210  may effectively override the “switching” functionality of tether  120  described above. 
     Additionally, the tethering safety system may be combined with other safety systems. For example, as discussed above, an infra-red system may be implemented such that the controller will not function if an infra-red signal between the controller  110  and a vehicle sensor is lost. This infra-red system effectively limits the operating range of the controller  110  by preventing it from operating if there is no direct path between the controller and the IR sensor Therefore, the controller  110  will not operate properly if it is outside the cab of the vehicle  130 . Additionally, the sensor may be in communication with one or more sensors (e.g., ultrasonic or weight sensors) that can detect when a person is located within the cab of the vehicle  130 . If the one or more sensors do not detect an operator inside the cab, the controller  110  may not function. An RF-proximity configuration may be implemented such that the controller will only function if it is closer to the vehicle  130  than it is to snowplow  140  itself.