Boom inclination detecting and stabilizing system

Abstract

Apparatuses and methods for controlling the stability of elevating systems, such as personnel lifts. In one embodiment, a stability control apparatus includes an angle detector and a signal processor. The angle detector is mounted to a boom of a personnel lift and configured to detect an angle of inclination of the boom relative to an independent reference frame independent of the personnel lift. The signal processor is operatively connected to the angle detector and is configured to receive a first signal initiated by the angle detector when the angle of inclination reaches a predetermined angle. The signal processor is further configured to output a second signal in response to receiving the first signal causing a boom control system to limit movement of the boom relative to the independent reference frame when the angle of inclination reaches the predetermined angle.

We claim:  
     
         1 . A stability control apparatus usable with a personnel lift, the personnel lift having a boom operatively connected to a chassis and a control system operatively connected to the boom for controlling movement of the boom relative to the chassis, the apparatus comprising: 
 an angle detector adapted to be operatively mounted to the boom, the angle detector configured to detect an angle of inclination of the boom, the angle of inclination being an angle between a longitudinal axis of the boom and an independent reference frame independent of the chassis; and    a signal processor operatively connected to the angle detector and adapted to be operatively connected to the control system, the signal processor configured to receive a first signal initiated by the angle detector when the angle of inclination reaches a predetermined angle, the signal processor further configured to output a second signal in response to receiving the first signal, the second signal causing the control system to limit movement of the boom relative to the independent reference frame when the angle of inclination reaches the predetermined angle.    
     
     
         2 . The stability control apparatus of  claim 1  wherein the angle detector is configured to detect the angle of inclination between the longitudinal axis of the boom and a horizontal line at least substantially normal to the direction of gravitational force.  
     
     
         3 . The stability control apparatus of  claim 1  wherein the angle detector is an accelerometer.  
     
     
         4 . The stability control apparatus of  claim 1  wherein the angle detector is a pendulum switch.  
     
     
         5 . The stability control apparatus of  claim 1  wherein the second signal causes the control system to limit pivotal movement of the boom relative to the independent reference frame when the angle of inclination reaches the predetermined angle.  
     
     
         6 . The stability control apparatus of  claim 1  wherein the chassis is a drive chassis configured for repositioning of the personnel lift, wherein the control system is operatively connected to the drive chassis for controlling repositioning of the drive chassis, and wherein the second signal causes the control system to limit repositioning of the drive chassis when the angle of inclination reaches the predetermined angle.  
     
     
         7 . The stability control apparatus of  claim 6  wherein the second signal causes the control system to prevent movement of the drive chassis from a first position to a second position when the angle of inclination reaches the predetermined angle.  
     
     
         8 . The stability control apparatus of  claim 7  wherein the second signal causes the control system to prevent movement of the drive chassis from a first position having a first slope to a second position having a second slope greater than the first slope when the angle of inclination reaches the predetermined angle.  
     
     
         9 . The stability control apparatus of  claim 1  further comprising an alarm system operatively connected to the signal processor, wherein the second signal causes the alarm system to activate when the angle of inclination reaches the predetermined angle.  
     
     
         10 . The stability control apparatus of  claim 9  wherein the alarm system is a visual alarm system.  
     
     
         11 . The stability control apparatus of  claim 10  wherein the visual alarm system includes flashing lights.  
     
     
         12 . The stability control apparatus of  claim 9  wherein the alarm system is an audible alarm system.  
     
     
         13 . The stability control apparatus of  claim 1  wherein the processor determines a boom speed based on the first signal received from the angle detector and outputs the second signal related to the boom speed.  
     
     
         14 . The stability control apparatus of  claim 1  wherein the angle detector is configured to detect the angle of inclination between the longitudinal axis of the boom and a horizontal line at least substantially normal to the direction of gravitational force, and wherein the predetermined angle is between about 30 degrees and about 90 degrees.  
     
     
         15 . The stability control apparatus of  claim 1  wherein the angle detector is configured to detect the angle of inclination between the longitudinal axis of the boom and a horizontal line at least substantially normal to the direction of gravitational force, and wherein the predetermined angle is between about 60 degrees and about 80 degrees.  
     
     
         16 . The stability control apparatus of  claim 1  wherein the predetermined angle is a first predetermined angle, wherein the second signal causes the control system to reduce boom speed when the angle of inclination reaches the first predetermined angle, wherein the signal processor is further configured to receive a third signal initiated by the angle detector when the angle of inclination reaches a second predetermined angle, the signal processor further configured to output a fourth signal in response to receiving the third signal, the fourth signal causing the control system to stop movement of the boom relative to the independent reference frame when the angle of inclination reaches the second predetermined angle.  
     
     
         17 . A stability control apparatus usable with an elevating system, the elevating system having a boom operatively connected to a chassis and a control system operatively connected to the boom for controlling movement of the boom relative to the chassis, the apparatus comprising: 
 an angle detector adapted to be operatively mounted to the elevating system, the angle detector configured to detect an angle of inclination, the angle of inclination being an angle between a portion of the elevating system and an independent reference frame independent of the chassis; and    a signal processor operatively connected to the angle detector and adapted to be operatively connected to the control system, the signal processor configured to receive a first signal initiated by the angle detector and output a second signal in response to receiving the first signal, the second signal causing the control system to limit movement of the boom relative to the independent reference frame.    
     
     
         18 . The stability control apparatus of  claim 17  wherein the angle detector is adapted to be operatively mounted to the boom and is configured to detect the angle of inclination between the boom and the independent reference frame.  
     
     
         19 . The stability control apparatus of  claim 17  wherein the angle detector is adapted to be operatively mounted to the chassis and is configured to detect the angle of inclination between the chassis and the independent reference frame.  
     
     
         20 . The stability control apparatus of  claim 17  wherein the angle detector is configured to detect the angle of inclination between a portion of the elevating system and a horizontal line at least substantially normal to the direction of gravitational force.  
     
     
         21 . The stability control apparatus of  claim 17  wherein the second signal causes the control system to limit pivotal movement of the boom relative to the independent reference frame.  
     
     
         22 . The stability control apparatus of  claim 17  wherein the chassis is a drive chassis configured for repositioning of the personnel lift, wherein the control system is operatively connected to the drive chassis for controlling repositioning of the drive chassis, and wherein the second signal causes the control system to limit repositioning of the drive chassis.  
     
     
         23 . The stability control apparatus of  claim 22  wherein the second signal causes the control system to prevent movement of the drive chassis from a first position to a second position.  
     
     
         24 . The stability control apparatus of  claim 23  wherein the second signal causes the control system to prevent movement of the drive chassis from a first position having a first slope to a second position having a second slope greater than the first slope.  
     
     
         25 . The stability control apparatus of  claim 17  further comprising an alarm system operatively connected to the signal processor, wherein the second signal causes the alarm system to activate.  
     
     
         26 . The stability control apparatus of  claim 17  wherein the processor determines a boom speed based on the first signal received from the angle detector and outputs the second signal related to the boom speed.  
     
     
         27 . A personnel lift comprising: 
 a chassis;    a boom pivotally connected relative to the chassis;    a boom control system operatively connected to the boom for controlling movement of the boom relative to the chassis;    an angle detector operatively mounted to the boom, the angle detector configured to detect an angle of inclination of the boom, the angle of inclination being an angle between a longitudinal axis of the boom and an independent reference frame independent of the chassis; and    a signal processor operatively connected to the angle detector and the control system, the signal processor configured to receive a first signal initiated by the angle detector when the angle of inclination reaches a predetermined angle, the signal processor further configured to output a second signal in response to receiving the first signal, the second signal causing the control system to limit movement of the boom relative to the independent reference frame when the angle of inclination reaches the predetermined angle.    
     
     
         28 . The personnel lift of  claim 27  wherein the boom is a primary boom having a first proximal end and a first distal end spaced apart from the first proximal end, and wherein the personnel lift further includes a secondary boom, the secondary boom having a second proximal end and a second distal end spaced apart from the second proximal end, the second proximal end of the secondary boom being pivotally connected adjacent to the chassis, and the first proximal end of the primary boom being pivotally connected to the second distal end of the secondary boom.  
     
     
         29 . The personnel lift of  claim 27  wherein the boom is an extendable boom and the personnel lift further includes a lift cylinder operatively connected to the extendable boom and the boom control system for pivoting the boom relative to the chassis.  
     
     
         30 . The personnel lift of  claim 27  wherein the angle detector is configured to detect the angle of inclination between the longitudinal axis of the boom and a horizontal line at least substantially normal to the direction of gravitational force.  
     
     
         31 . The personnel lift of  claim 27  wherein the second signal causes the control system to limit pivotal movement of the boom relative to the independent reference frame when the angle of inclination reaches the predetermined angle.  
     
     
         32 . The personnel lift of  claim 27  wherein the chassis is a drive chassis configured for repositioning of the personnel lift, wherein the control system is operatively connected to the drive chassis for controlling repositioning of the drive chassis, and wherein the second signal causes the control system to limit repositioning of the drive chassis when the angle of inclination reaches the predetermined angle.  
     
     
         33 . The personnel lift of  claim 32  wherein the second signal causes the control system to prevent movement of the drive chassis from a first position having a first slope to a second position having a second slope greater than the first slope when the angle of inclination reaches the predetermined angle.  
     
     
         34 . The personnel lift of  claim 27  further comprising an alarm system operatively connected to the signal processor, wherein the second signal causes the alarm system to activate when the angle of inclination reaches the predetermined angle.  
     
     
         35 . The personnel lift of  claim 27  wherein the processor determines a boom speed based on the first signal received from the angle detector and outputs the second signal related to the boom speed.  
     
     
         36 . The personnel lift of  claim 27  wherein the predetermined angle is a first predetermined angle, wherein the second signal causes the control system to reduce boom speed when the angle of inclination reaches the first predetermined angle, wherein the signal processor is further configured to receive a third signal initiated by the angle detector when the angle of inclination reaches a second predetermined angle, the signal processor further configured to output a fourth signal in response to receiving the third signal, the fourth signal causing the control system to stop movement of the boom relative to the independent reference frame when the angle of inclination reaches the second predetermined angle.  
     
     
         37 . The personnel lift of  claim 27  wherein the boom is a primary boom having a first proximal end and a first distal end spaced apart from the first proximal end, and wherein the personnel lift further comprises: 
 a base mounted to the chassis; and  
 a secondary boom, the secondary boom having a second proximal end and a second distal end spaced apart from the second proximal end, the second proximal end of the secondary boom being pivotally connected to the base, and the first proximal end of the primary boom being pivotally connected to the second distal end of the secondary boom.  
 
     
     
         38 . The personnel lift of  claim 27  wherein the boom is a primary boom having a first proximal end and a first distal end spaced apart from the first proximal end, and wherein the personnel lift further comprises: 
 a rotatable base rotatably mounted to the chassis; and  
 a secondary boom, the secondary boom having a second proximal end and a second distal end spaced apart from the second proximal end, the second proximal end of the secondary boom being pivotally connected to the base, and the first proximal end of the primary boom being pivotally connected to the second distal end of the secondary boom.  
 
     
     
         39 . An elevating system comprising: 
 a chassis;    a boom pivotally connected relative to the chassis;    a control system operatively connected to the boom for controlling movement of the boom;    an angle detector adapted to be operatively mounted to the elevating system, the angle detector configured to detect an angle of inclination, the angle of inclination being an angle between a portion of the elevating system and an independent reference frame independent of the chassis; and    a signal processor operatively connected to the angle detector and adapted to be operatively connected to the control system, the signal processor configured to receive a first signal initiated by the angle detector and output a second signal in response to receiving the first signal, the second signal causing the control system to limit movement of the boom relative to the independent reference frame.    
     
     
         40 . The elevating system of  claim 39  wherein the angle detector is adapted to be operatively mounted to the boom and is configured to detect the angle of inclination between the boom and the independent reference frame.  
     
     
         41 . The elevating system of  claim 39  wherein the angle detector is adapted to be operatively mounted to the chassis and is configured to detect the angle of inclination between the chassis and the independent reference frame.  
     
     
         42 . The elevating system of  claim 39  wherein the angle detector is configured to detect the angle of inclination between a portion of the elevating system and a horizontal line at least substantially normal to the direction of gravitational force.  
     
     
         43 . The elevating system of  claim 39  wherein the second signal causes the control system to limit pivotal movement of the boom relative to the independent reference frame.  
     
     
         44 . The elevating system of  claim 39  wherein the chassis is a drive chassis configured for repositioning of the personnel lift wherein the control system is operatively connected to the drive chassis for controlling repositioning of the drive chassis, and wherein the second signal causes the control system to limit repositioning of the drive chassis.  
     
     
         45 . The elevating system of  claim 44  wherein the second signal causes the control system to prevent movement of the drive chassis from a first position to a second position.  
     
     
         46 . The elevating system of  claim 44  wherein the second signal causes the control system to prevent movement of the drive chassis from a first position having a first slope to a second position having a second slope greater than the first slope.  
     
     
         47 . The elevating system of  claim 39  further comprising an alarm system operatively connected to the signal processor, wherein the second signal causes the alarm system to activate.  
     
     
         48 . The elevating system of  claim 39  wherein the processor determines a boom speed based on the first signal received from the angle detector and outputs the second signal related to the boom speed.  
     
     
         49 . A method for controlling the stability of a personnel lift, the personnel lift having a boom operatively connected to a chassis and a boom control system operatively connected to the boom for controlling movement of the boom relative to the chassis, the method comprising: 
 providing an angle detector adapted to be operatively mounted to the boom, the angle detector configured to detect an angle of inclination of the boom, the angle of inclination being an angle between a longitudinal axis of the boom and an independent reference frame independent of the chassis;    providing a signal processor operatively connected to the angle detector and adapted to be operatively connected to the control system, the signal processor configured to receive a first signal initiated by the angle detector when the angle of inclination reaches a predetermined angle, the signal processor further configured to output a second signal in response to receiving the first signal, the second signal causing the control system to limit movement of the boom relative to the independent reference frame when the angle of inclination reaches the predetermined angle;    detecting when the boom has pivoted to the predetermined angle; and    limiting movement of the boom when the boom has pivoted to the predetermined angle.    
     
     
         50 . The method of  claim 49  wherein providing an angle detector includes providing an angle detector configured to detect the angle of inclination between the longitudinal axis of the boom and a horizontal line at least substantially normal to the direction of gravitational force.  
     
     
         51 . The method of  claim 49  wherein providing an angle detector includes providing an accelerometer.  
     
     
         52 . The method of  claim 49  wherein limiting movement of the boom when the boom has pivoted to the predetermined angle includes limiting pivotal movement of the boom relative to the independent reference frame.  
     
     
         53 . The method of  claim 49  wherein limiting movement of the boom when the boom has pivoted to the predetermined angle includes limiting repositioning of the chassis.  
     
     
         54 . The method of  claim 49  further comprising activating an alarm system when the boom has pivoted to the predetermined angle.  
     
     
         55 . The method of  claim 49  further comprising determining a boom speed when the boom has pivoted to the predetermined angle.  
     
     
         56 . The method of  claim 49  wherein limiting movement of the boom when the boom has pivoted to the predetermined angle includes limiting movement of the boom when the boom has pivoted to an angle between about 30 degrees and about 90 degrees.  
     
     
         57 . The method of  claim 49  wherein limiting movement of the boom when the boom has pivoted to the predetermined angle includes limiting movement of the boom when the boom has pivoted to an angle between about 60 degrees and about 80 degrees.  
     
     
         58 . The method of  claim 49  wherein limiting movement of the boom when the boom has pivoted to the predetermined angle includes reducing boom speed when the angle of inclination reaches a first predetermined angle, wherein providing the signal processor includes providing a signal processor further configured to receive a third signal initiated by the angle detector when the angle of inclination reaches a second predetermined angle, the signal processor further configured to output a fourth signal in response to receiving the third signal, the fourth signal causing the control system to further limit movement of the boom relative to the independent reference frame when the angle of inclination reaches the second predetermined angle, and wherein the method further comprises further limiting movement of the boom when the angle of inclination reaches the second predetermined angle.  
     
     
         59 . The method of  claim 58  wherein further limiting movement of the boom when the angle of inclination reaches the second predetermined angle includes stopping boom movement.  
     
     
         60 . The method of  claim 58  wherein further limiting movement of the boom when the angle of inclination reaches the second predetermined angle includes stopping chassis movement.  
     
     
         61 . A method of moving a boom from a first position to a second position, the boom being operatively connected to a chassis and a control system, the control system controlling movement of the boom relative to the chassis, the method comprising: 
 detecting a boom angle relative to an independent reference frame independent of the chassis;    allowing pivotal movement of the boom relative to the independent reference frame when the boom angle relative to the independent reference frame is within a first range; and    limiting pivotal movement of the boom relative to the independent reference frame when the boom angle relative to the independent reference frame is within a second range, the second range including steeper angles of inclination than the first range.    
     
     
         62 . The method of  claim 61  wherein limiting pivotal movement of the boom includes reducing boom speed relative to the independent reference frame.  
     
     
         63 . The method of  claim 61  further comprising preventing pivotal movement of the boom when the boom angle relative to the independent reference frame is within a third range, the third range including steeper angles of inclination than the second range.