Variable vibratory mechanism

Abstract

A vibratory mechanism having a first eccentric weight coaxially rotatable with a second eccentric weight and a clutch operatively connecting the first and second eccentric weights. The clutch allows for co-rotation of the first and second eccentric weights and the ability to index the first eccentric weight relative to second eccentric weight to vary the vibrational amplitude.

What is claimed is:  
     
         1 . A vibratory mechanism comprising: 
 a first eccentric weight rotatably supported within a housing;    a second eccentric weight being coaxially rotatable with said first eccentric weight; and    a clutch operatively connecting said first and second eccentric weights, said clutch being operative to index said first eccentric weight relative to said second eccentric weight to change a vibration amplitude of the vibratory mechanism.    
     
     
         2 . The vibratory mechanism in  claim 1 , wherein said clutch is a torque limiting clutch, interposed said first and second eccentric weights, that slips to allow relative movement between said first and second eccentric weights.  
     
     
         3 . The vibratory mechanism in  claim 2 , wherein said clutch is an adjustable clutch.  
     
     
         4 . The vibratory mechanism in  claim 1 , including a motor for driving said first and second eccentric weights.  
     
     
         5 . The vibratory mechanism in  claim 4 , including a shaft connecting said motor to said first and second eccentric weights.  
     
     
         6 . The vibratory mechanism in  claim 4 , including a variable power source connected with said motor.  
     
     
         7 . The vibratory mechanism in  claim 4 , wherein and an infinitely variable electric displacement controller controls said power source.  
     
     
         8 . A work machine, comprising: 
 a compacting drum supporting said work machine; and    a vibratory mechanism as set for in  claim 1 .    
     
     
         9 . A work machine comprising: 
 a compacting drum supporting said work machine;    a vibratory mechanism coaxially positioned within said compacting drum;    said vibratory mechanism including: 
 a first eccentric weight rotatably supported within a housing;  
 a second eccentric weight coaxially rotatable with said first eccentric weight; and  
 a clutch operatively connecting said first and second eccentric weights, said clutch being operative to index said first eccentric weight relative to said second eccentric weight to change a vibration amplitude of the vibratory mechanism.  
   
     
     
         10 . The work machine recited in  claim 9 , wherein said clutch is a torque limiting clutch that slips to allow relative movement between said first and second eccentric weights with an abrupt increase or decrease in rotation speed.  
     
     
         11 . The work machine recited in  claim 10 , wherein said clutch is an adjustable clutch.  
     
     
         12 . The work machine recited in  claim 9 , further including means for limiting the phase difference between said first and second eccentric weights.  
     
     
         13 . The work machine recited in  claim 12 , wherein said limiting means is a mechanical stop fixedly secured to the second eccentric weight, said first eccentric weight striking said stop at a predetermined relative position of the first and second eccentric weights.  
     
     
         14 . The work machine recited in  claim 9 , further including a speed sensor that senses a speed of at least one of the first and second eccentric weights, and a computer controller that controls operation of said clutch based on an output of said sensor.  
     
     
         15 . The work machine recited in  claim 9 , further including an accelerometer that senses an amount of acceleration created by said vibratory compactor, and a computer controller that controls said clutch based on an output of said accelerometer.  
     
     
         16 . A method for controlling amplitude of a vibratory mechanism, the vibratory mechanism having first and second eccentric weights coaxially rotatably coupled by a torque limiting clutch operatively connecting, comprising: 
 abruptly changing a speed of one of the first and second eccentric weights to cause the torque limiting clutch to slip, thereby causing the first and second eccentric weights to move farther apart or closer together to change the vibration amplitude.    
     
     
         17 . The method recited in  claim 16 , including: 
 determining at least an amount of vibration; and    changing the vibration amplitude based on the detected vibration.    
     
     
         18 . The method recited in  claim 16 , including repeating said speed changing step to arrive at a desired vibration amplitude.  
     
     
         19 . The method recited in  claim 16 , including monitoring a vibration frequency, and controlling the vibrator so that a desired area of vibration frequency versus vibration amplitude is maintained.  
     
     
         20 . The method recited in  claim 19 , wherein as the vibration frequency is increased, the vibration amplitude is decreased, and wherein as the vibration frequency is decreased, the vibration amplitude is increased.  
     
     
         21 . The method recited in  claim 16 , including monitoring a ground speed of a vehicle that includes the vibratory compactor, and controlling the ground speed and the vibration amplitude relative to each other.