Lawnmower tilt sensor apparatus and method

Abstract

A lawnmower comprising a frame, an engine supported by the frame, a mower deck supported by the frame, a rotating cutting blade disposed below the mower deck. A PTO is coupled to the engine and the cutting blade to rotationally drive the cutting blade. A drive system is connected to the frame and coupled to the engine to drive or propel the lawnmower. The lawnmower includes a tilt sensor for sensing a tilt angle representing the orientation of the lawnmower with respect to a horizontal level plane. A signal indicator may provide a notice signal when the tilt angle exceeds a pre-determined check angle. A CPU is electrically coupled between the tilt sensor and signal indicator, and activates the signal indicator in response to the tilt sensor sensing that the lawnmower is tilted beyond the threshold angle to warn the lawnmower operator of a tilt condition.

1 . A riding lawnmower comprising: 
 a frame;    an engine supported by the frame;    a mower deck supported by the frame;    a rotating cutting blade disposed below the mower deck and selectively rotating under the influence of the engine to cut vegetation under the mower deck;    a drive system connected to the frame for driving the lawnmower;    a tilt sensor for sensing a tilt condition of the lawnmower with respect to horizontal;    a CPU electrically communicating with the tilt sensor to monitor a tilt angle of the lawnmower and creating an output signal in response to the tilt sensor indicating that the lawnmower is tilted beyond a selected angle; and    a signal indicator electrically communicating with the CPU and providing a notice signal to an operator of the lawnmower in response to receiving the output signal from the CPU.    
   
   
       2 . The lawnmower of  claim 1 , wherein the drive system includes first and second drive wheels and first and second control levers for the independent forward and reverse operation of the respective first and second drive wheels.  
   
   
       3 . The lawnmower of  claim 1 , wherein the tilt sensor creates a check signal in response to the tilt angle of the lawnmower exceeding a check angle, and a limit signal in response to the tilt angle of the lawnmower exceeding a limit angle, the limit angle being larger than the check angle; wherein the signal indicator includes a check indicator and a limit indicator different from the check indicator; and wherein the CPU creates a first output signal to activate the check indicator in response to the CPU receiving the check signal and creates a second output signal to activate the limit indicator in response to the CPU receiving the limit signal.  
   
   
       4 . The lawnmower of  claim 3 , wherein the tilt sensor includes a check switch set to close a first electrical circuit and create the check signal in response to the tilt angle of the lawnmower exceeding the check angle, and a limit switch set to close a second electrical circuit and create the limit signal in response to the tilt angle of the lawnmower exceeding the limit angle.  
   
   
       5 . The lawnmower of  claim 3 , further comprising a clock electrically coupled to the CPU, wherein the CPU only creates the first output signal in response to receiving the check signal for at least one continuous second as measured by the clock; and wherein the CPU only creates the second output signal in response receiving the limit signal for at least five continuous seconds as measured by the clock.  
   
   
       6 . The lawnmower of  claim 1 , wherein the CPU, substantially simultaneously with activating the output signal, causes the cutting blade to be disengaged from the engine while maintaining the drive system in control of driving the lawnmower.  
   
   
       7 . The lawnmower of  claim 1 , wherein the tilt sensor includes an inclinometer for measuring the tilt angle of the lawnmower; and wherein the CPU causes the signal indicator to display the tilt angle of the lawnmower as measured by the inclinometer.  
   
   
       8 . The lawnmower of  claim 1 , further comprising a clock electrically coupled to the CPU, wherein the CPU creates the output signal only in response to the tilt sensor sensing that the lawnmower is tilted beyond the selected angle for at least one second as measured by the clock.  
   
   
       9 . The lawnmower of  claim 8 , further comprising a memory device electrically coupled to the CPU, wherein the CPU records in the memory device information received from the clock substantially simultaneously with creation of the output signal.  
   
   
       10 . The lawnmower of  claim 1 , wherein the signal indicator includes a speaker for providing an audible signal.  
   
   
       11 . The lawnmower of  claim 1 , wherein the signal indicator includes a strobe light for providing a visual signal.  
   
   
       12 . A riding lawnmower comprising: 
 a frame;    an engine supported by the frame;    a mower deck supported by the frame;    a rotating cutting blade disposed below the mower deck and selectively rotating under the influence of the engine to cut vegetation under the mower deck;    means for driving the lawnmower;    means for sensing a tilt angle representing the orientation of the lawnmower with respect to a reference plane;    a CPU coupled to the means for sensing, the means for sensing providing a check signal to the CPU when the tilt angle exceeds a pre-determined check angle, the means for sensing providing a limit signal to the CPU when the tilt angle exceeds the limit angle, the limit angle being greater than the check angle; and    a signal indicator providing a notice signal being at least one of an audible signal and a visual signal in response to the CPU receiving the check signal.    
   
   
       13 . The lawnmower of  claim 12 , wherein the means for sensing includes an inclinometer; wherein the signal indicator includes a display screen; and wherein the notice signal includes a visual display on the display screen of the current tilt angle of the lawnmower.  
   
   
       14 . The lawnmower of  claim 12 , wherein the means for sensing includes separate check and limit switches for providing respective check and limit signals when the tilt angle of the lawnmower exceeds preset check and limit angles; wherein the CPU creates first and second output signals in response to receiving the respective check and limit signals from the means for sensing; and wherein the signal indicator generates different notice signals in response to receiving the respective first and second output signals from the CPU.  
   
   
       15 . The lawnmower of  claim 12 , wherein the CPU, substantially simultaneously with activating the signal indicator, causes the cutting blade to be disengaged from the engine while maintaining the means for driving in control of driving the lawnmower.  
   
   
       16 . A method of providing a signal for the operating angle of a lawnmower having a frame, an engine supported by the frame, a mower deck supported by the frame, a rotating cutting blade disposed below the mower deck and a PTO connecting the cutting blade and the engine and rotationally driving the cutting blade, and means for driving the lawnmower, the method comprising the acts of: 
 measuring with a tilt sensor a tilt angle representing the orientation of the lawnmower with respect to a reference plane;    sending a check signal from the tilt sensor to a CPU when the tilt angle exceeds a pre-determined check angle;    sending a limit signal from the tilt sensor to a CPU when the tilt angle exceeds a pre-determined limit angle, the limit angle being greater than the check angle; and    activating a notice signal including at least one of an audible signal and a visual signal when the CPU receives the check signal.    
   
   
       17 . The method of  claim 16 , further comprising the act of logging at least the time of activation of the check and limit signals in a storage device.  
   
   
       18 . The method of  claim 16 , wherein the act of activating the notice signal further comprises activating the notice signal when the CPU continuously receives the check signal for at least about one continuous second.  
   
   
       19 . The method of  claim 16 , further comprising the act of activating an additional notice signal when the CPU receives the limit signal for at least about five continuous seconds.