Control function-power operated lift gate

Abstract

A lift type tailgate on a passenger van type vehicle body is operated by an electric motor powered actuator with an electronic control circuit utilizing a microprocessor operating under program control to respond to user-initiated opening and closing signals to move the tailgate in the selected direction. In the control circuit, feedback information to the microprocessor indicative of tailgate position is provided by a potentiometer coupled with the actuator motor and the microprocessor is programmed to operate with this information to stop the tailgate at a wide open position, a partially closed position and a fully closed position. Obstruction detection is performed by the microprocessor using an obstruction detection circuit and additionally by monitoring the position signal input from the potentiometer to stop the tailgate on encountering an obstacle. Activation of a tailgate latching mechanism is performed under the control of the microprocessor using a solenoid drive circuit and warning or alerting sounds indicating tailgate closure operation including tailgate stoppage at the partially closed position are provided in accordance with audio data received from the microprocessor.

What is claimed is:  
     
       1. In combination, a motor vehicle body having a rear opening, a tailgate mounted for swinging movement on said vehicle body about an upper edge of said tailgate to open and close said rear opening, latch means operable to latch said tailgate to said vehicle body when said tailgate is swung to a fully closed position, said latch means including solenoid means operable on energization to unlatch said tailgate, a tailgate power actuator mechanism operable to swing said tailgate to open and close said rear opening, said tailgate power actuator mechanism including a reversible electric motor operable on energization in an opening mode to swing said tailgate to a fully open position and operable on energization in a closing mode to swing said tailgate to said fully closed position, an alarm device operable on energization in one sound mode to emit one kind of warning sound and on energization in another sound mode to emit another kind of warning sound, an electronic control system including a microprocessor controller operable to control energization of said solenoid means and said motor and said alarm device, manually controlled switch means operable to provide an opening signal and a closing signal to said controller, said controller responsive to said opening signal to energize said solenoid means to unlatch said tailgate and to energize said motor in said opening mode to move said tailgate toward said fully open position, said controller responsive to said closing signal to energize said motor in said closing mode to move said tailgate toward said fully closed position, obstruction signaling means operable to provide an obstruction signal to said controller in response to said tailgate contacting an obstacle during either opening or closing movement, said controller responsive to said obstruction signal to cease energization of said motor to stop said tailgate, tailgate position signaling means operable to provide a position signal indicative of tailgate position, said controller responsive to said position signal to cease energization of said motor when said motor is in said opening mode and said tailgate moves into said fully opened position, said controller responsive to said position signal to cease energization of said motor when said motor is in said closing mode and said tailgate moves into either said fully closed position or a predetermined partially closed position, said controller responsive to a repeated closing signal from said manually controlled switch means to energize said motor in said closing mode to move said tailgate from said partially closed position to said fully closed position, and said controller responsive to said position signal and said closing signal to energize said alarm device to emit said one kind of warning sound when said tailgate is moving between said fully opened position and said partially closed position and to emit said other kind of warning sound when said tailgate is moving between said partially closed position and said fully closed position. 
     
     
       2. The combination set forth in  claim 1  wherein said position signaling means includes a potentiometer coupled to said motor to provide said position signal. 
     
     
       3. In combination, a motor vehicle body having a rear opening, a tailgate mounted for swinging movement on said vehicle body about an upper edge of said tailgate to open and close said rear opening, latch means operable to latch said tailgate to said vehicle body when said tailgate is swung to a fully closed position, said latch means including solenoid means operable on energization to unlatch said tailgate, a tailgate power actuator mechanism operable to swing said tailgate to open and close said rear opening, said tailgate power actuator mechanism including a reversible electric motor operable on energization in an opening mode to swing said tailgate to a fully open position and operable on energization in a closing mode to swing said tailgate to said fully closed position, an electronic control system including a microprocessor controller operable to control energization of said solenoid means and said motor, manually controlled switch means operable to provide an opening signal and a closing signal to said controller, said controller responsive to said opening signal to energize said solenoid means to unlatch said tailgate and to energize said motor in said opening mode to move said tailgate toward said fully open position, said controller responsive to said closing signal to energize said motor in said closing mode to move said tailgate toward said fully closed position, obstruction signaling means operable to provide an obstruction signal to said controller in response to said tailgate contacting an obstacle during either opening or closing movement, said controller responsive to said obstruction signal to cease energization of said motor to stop said tailgate, tailgate position signaling means coupled to said motor operable to provide a position signal indicative of tailgate position, said controller responsive to said position signal to cease energization of said motor when said motor is in said opening mode and said tailgate moves into said fully opened position, said controller responsive to said position signal to cease energization of said motor when said motor is in said closing mode and said tailgate moves into either said fully closed position or a predetermined partially closed position, and said controller responsive to a repeated closing signal from said manually controlled switch means to energize said motor in said closing mode to move said tailgate from said partially closed position to said fully closed position. 
     
     
       4. The combination set forth in  claim 3  wherein said position signaling means includes a potentiometer having a wiper arm coupled to said motor to provide said position signal. 
     
     
       5. In combination, a motor vehicle body having a rear opening, a tailgate mounted for swinging movement on said vehicle body about an upper edge of said tailgate to open and close said rear opening, a tailgate power actuator mechanism operable to swing said tailgate to open and close said rear opening, said tailgate power actuator mechanism including a reversible electric motor operable on energization in an opening mode to swing said tailgate to a fully open position and operable on energization in a closing mode to swing said tailgate to said fully closed position, an electronic control system including a microprocessor controller operable to control energization of said motor, manually controlled switch means operable to provide an opening signal and a closing signal to said controller, said controller responsive to said opening signal to energize said motor in said opening mode to move said tailgate toward said fully open position, said controller responsive to said closing signal to energize said motor in said closing mode to move said tailgate to a predetermined partially closed position, obstruction signaling means operable to provide an obstruction signal to said controller in response to said tailgate contacting an obstacle during either opening or closing movement, said controller responsive to said obstruction signal to cease energization of said motor to stop said tailgate, tailgate position signaling means operable to provide a position signal indicative of tailgate position, said controller responsive to said position signal to cease energization of said motor when said motor is in said opening mode and said tailgate moves into said fully opened position, said controller responsive to said position signal to cease energization of said motor when said motor is in said closing mode and said tailgate moves into either a fully closed position or said predetermined partially closed position, and said controller responsive to a repeated closing signal from said manually controlled switch means to energize said motor in said closing mode to move said tailgate from said partially closed position to said fully closed position. 
     
     
       6. The combination set forth in  claim 5  wherein said position signaling means includes a potentiometer having a wiper arm coupled to said motor to provide said position signal. 
     
     
       7. A powered lift tailgate mechanism for use between a vehicle body and a tailgate comprising: 
       
         a drive system coupled to said vehicle body and to said tailgate, including an electric motor for generating mechanical forces to operate said tailgate; and  
       
       
         electronic controller for supplying operating current to said electric motor, said controller including a sensor which electrically monitors electrical operating conditions of said electric motor, said electronic controller automatically inhibiting the supply of operating current to said electric motor when said motor exhibits operating conditions beyond a predetermined set point indicative of a tailgate obstruction condition, said sensor electrically communicating with said electronic controller and providing said electrical operating conditions to said electronic controller, wherein said sensor is a MOSFET, said MOSFET electrically communicating with said motor to supply said operating current to said electric motor, said MOSFET having an output that provides a logic signal indicative of temperature conditions associated with the supplying of operating current to said electric motor, wherein said electronic controller is responsive to said MOSFET to automatically inhibit the supplying of operating current to said electric motor when said sensed temperature conditions exceed a predetermined condition indicative of a tailgate obstruction condition.  
       
     
     
       8. A powered lift tailgate mechanism as claimed in  claim 7 , wherein said sensor is a first pair and a second pair of said MOSFETs, said first pair of MOSFETs in electrical communication with said electric motor, said first pair of MOSFETs for providing said operating current to said electric motor in such a way as to turn said electric motor in a first direction said second pair of MOSFETs in electrical communication with said electric motor, said second pair of MOSFETs for providing said operating current to said electric motor in such a way as to turn said electric motor in a second direction.  
     
     
       9. A powered lift tailgate mechanism as claimed in  claim 7 , wherein said electronic controller includes an audible alarm responsive to said system, said audible alarm providing an audible signal when said motor exhibits operating conditions indicative of a tailgate obstruction condition.  
     
     
       10. A powered lift tailgate mechanism for use beetween a vehicle body and a tailgate comprising: 
       
         a drive system coupled to said vehicle body and to said tailgate, including an electric motor for generating mechanical forces to effect closing movement of said tailgate;  
       
       
         a position sensor means for providing an indication of the position of said tailgate and for defining a first range of positions and a second range of positions;  
       
       
         an electronic controller for suppling operating current to said electric motor, said controller including an audible signal generating system responsive to said position sensor; and  
       
       
         said audible signal generating system upon closing movement of said tailgate providing a first audible signal when said tailgate is within said first range of positions and providing a second audible signal when said tailgate is within said second range of positions.  
       
     
     
       11. A powered lift tailgate mechanism as claimed in  claim 10 , wherein said position sensor means is a potentiometer coupled to said electric motor, said potentiometer providing a position signal indicative of said position of said tailgate to said electronic controller, said audible signal generating system providing said first audible signal and said second audible signal in response to said position signal.  
     
     
       12. A powered lift tailgate mechanism as claimed in  claim 10 , further comprising: 
       
         a solenoid latching mechanism fixedly attached to said vehicle body; and  
       
       
         a microprocessor electronically communicating with said position sensor means, said electronic controller and said solenoid latching mechanism, said microprocessor providing a signal to said electronic controller to inhibit operating current to said electric motor and activate said solenoid latching mechanism when said position sensor means provides a signal indicative of said tailgate being in a fully closed position.  
       
     
     
       13. A powered lift tailgate mechanism as claimed in  claim 10 , wherein said first range of positions is greater than six inches and said second range of positions is less than and equal to six inches.  
     
     
       14. A powered lift tailgate mechanism as claimed in  claim 10 , wherein said audible signal generating system further comprises a piezoelectric element for generating said audible signal.  
     
     
       15. A powered lift tailgate mechanism for use between a vehicle body and a tailgate comprising: 
       
         a drive system coupled to said vehicle body and to said tailgate, including an electric motor for generating mechanical forces to operate said tailgate; and  
       
       
         electronic controller for supplying operating current to said electric motor, said controller including a sensor which electrically monitors electrical operating conditions of said electric motor, said electronic controller automatically inhibiting the supply of operating current to said electric motor when said motor exhibits operating conditions beyond a predetermined set point indicative of a tailgate obstruction condition, said sensor electrically communicating with said electronic controller and providing said electrical operating conditions to said electronic controller, wherein said sensor is an obstruction detection circuit, said obstruction detection circuit being in sensing communication with said electric motor and providing a pulse train indicative of motor speed to a logic circuit receptive of said pulse train and operative to inhibit said operating current when said motor speed drops below a predetermined value indicative of said tailgate obstruction condition.  
       
     
     
       16. A powered lift tailgate mechanism as claimed in  claim 15 , wherein said electronic controller includes an audible alarm responsive to said system, said audible alarm providing an audible signal when said motor exhibits operating conditions indicative of a tailgate obstruction condition.  
     
     
       17. A powered lift tailgate mechanism for use between a vehicle body and a tailgate comprising: 
       
         a drive system coupled to said vehicle body and to said tailgate, including an electric motor for generating mechanical forces to operate said tailgate; and  
       
       
         electronic controller for supplying operating current to said electric motor, said controller including a sensor which electrically monitors electrical operating conditions of said electric motor, said electronic controller automatically inhibiting the supply of operating current to said electric motor when said motor exhibits operating conditions beyond a predetermined set point indicative of a tailgate obstruction condition, said sensor electrically communicating with said electronic controller and providing said electrical operating conditions to said electronic controller, wherein said sensor is a potentiometer, said potentiometer coupled to said tailgate, a microprocessor electrically communicating with said potentiometer, said potentiometer providing a position signal to said microprocessor indicative of a position of said tailgate, said microprocessor further comprising a means for calculating a rate of change of position of said tailgate based on said position signal, said microprocessor inhibiting said operating current when said rate of change drops below a predetermined value which is indicative of said tailgate obstruction condition.  
       
     
     
       18. A powered lift tailgate mechanism as claimed in  claim 17  wherein said electronic controller includes an audible alarm responsive to said system, said audible alarm providing an audible signal when said motor exhibits operating conditions indicative of a tailgate obstruction condition.  
     
     
       19. A powered lift tailgate mechanism for use between a vehicle body and a tailgate comprising: 
       
         a drive system coupled to said vehicle body and to said tailgate, including an electric motor for generating mechanical forces to operate said tailgate;  
       
       
         an electronic controller for supplying operating current to said electric motor, said controller including an obstruction detection circuit to monitor operating conditions of said drive system, said electronic controller automatically inhibiting the supply of operating current to said electric motor when said obstruction detection circuit indicates operation of said drive system beyond a predetermined set point indicative of a tailgate obstruction condition, and  
       
       
         a remote entry receiver for receiving a wireless transmission, said signal receiver providing one of an opening and a closing signal to said electronic controller upon receipt of said transmission, said electronic controller supplying operating current to move said tailgate in one of an opening and a closing direction in response to said one of an opening and a closing signal.  
       
     
     
       20. A powered lift tailgate mechanism for use between a vehicle body and a tailgate comprising: 
       
         a drive system coupled to said vehicle body and to said tailgate, including an electric motor for generating mechanical forces to operate said tailgate; and  
       
       
         an electronic controller for supplying operating current to said electric motor, said controller including a sensor which provides a logic signal indicative of temperature conditions associated with the supplying of operating current to said electric motor, wherein said electronic controller electrically communicates with said sensor and is responsive to said logic signal to automatically inhibit the supplying of operating current to said electric motor when said sensed temperature conditions exceed a predetermined condition indicative of a tailgate obstruction condition.  
       
     
     
       21. A powered lift tailgate mechanism for use between a vehicle body and a tailgate comprising: 
       
         a drive system coupled to said vehicle body and to said tailgate, including an electric motor for generating mechanical forces to operate said tailgate; and  
       
       
         an electronic controller for supplying operating current to said electric motor, said controller including an obstruction detection circuit, said obstruction detection circuit being in sensing communication with said electric motor and providing a pulse train indicative of motor speed to a logic circuit receptive of said pulse train and operative to inhibit said operating current when said motor speed drops below a predetermined value indicative of said tailgate obstruction condition.  
       
     
     
       22. A powered lift tailgate mechanism for use between a vehicle body and a tailgate comprising: 
       
         a drive system coupled to said vehicle body and to said tailgate, including an electric motor for generating mechanical forces to operate said tailgate; and  
       
       
         an electronic controller for supplying operating current to said electric motor, said controller including a potentiometer providing a position signal indicative of a position of said tailgate, wherein said electronic controller electrically communicates with said potentiometer and is responsive to said position signal to automatically inhibit said operating current when a rate of change of said position drops below a predetermined value which is indicative of a tailgate obstruction condition.