Height control arrangement for a strike-off plate

Abstract

A height control arrangement for a strike-off plate of an asphalt paver screed assembly is disclosed. The screed assembly has at least one main screed unit and at least one screed extension unit mounted in front of the main screed unit. The height control arrangement includes an actuator connected with the strike-off plate mounted in front of the main screed unit at a position ahead of the screed extension unit. A sensor measures the amount of material built up behind the strike off plate and sends an input signal to a controller responsive to the amount of material. The controller sends a control signal to the actuator to adjust the height of the strike off plate responsive to the magnitude of the input signal.

1 . A height control arrangement for a strike-off plate of an asphalt paver screed assembly, said screed assembly having at least one main screed unit and at least one screed extension unit mounted in front of said main screed unit and being laterally movable beyond one end of said main screed unit, said height control arrangement comprising: 
 said strike-off plate being mounted in front of the main screed unit at a position ahead of the screed extension unit;    an actuator connected with said strike-off plate;    a sensor mounted behind said strike-off plate and in front of the main screed unit and adapted for measuring an amount of material; and    a controller connected to control the actuator responsive to the amount of material so as to adjust the height of said strike-off plate.    
     
     
         2 . The height control arrangement of  claim 1  wherein said sensor measures the amount of material by vision.  
     
     
         3 . The height control arrangement of  claim 1  wherein said sensor measures the amount of material by contact.  
     
     
         4 . The height control arrangement of  claim 1  includes a linkage mechanism pivotally supported by a support arm mechanism, said linkage mechanism having a first distal end being pivotally connected to said actuator and a second distal end connected to said strike-off plate.  
     
     
         5 . The height control arrangement of  claim 4  wherein said linkage mechanism is length adjustable.  
     
     
         6 . A method for controlling the height of a strike off plate of an asphalt paver screed assembly, said screed assembly having at least one main screed unit and at least one screed extension unit mounted in front of said main screed unit comprising the steps of: 
 sensing an amount of material built up behind said strike off plate and in front of said main screed unit; and    adjusting the height of said strike off plate in responsive to the amount of material sensed.    
     
     
         7 . The method of  claim 6  wherein the step of sensing includes the step of sending a signal responsive to the amount of material sensed to a controller.  
     
     
         8 . The method of  claim 7  including the step of comparing the signal responsive to the amount of material sensed to stored data.  
     
     
         9 . The method of  claim 6  including the step of actuating an actuator to adjust the height of said strike off plate.