Vibration isolator for a pneumatic pole or backfill tamper

Abstract

A percussion action pneumatic tool for compacting backfill areas including a vibration isolator and a percussion mechanism. The vibration isolator includes an inner shaft and an outer sleeve attached to a pair of springs. The springs dampen vibration or feedback transferred from the percussion mechanism to the outer sleeve and felt by the operator. The percussion mechanism includes a pair of elbows and an air conduit which allows the airflow to move through a second flow path into a second air space when the valve assembly directs the airflow through the second flow path.

We claim: 
     
         1 . A vibration isolator apparatus for use with a percussion mechanism comprising:
 an inner shaft including an upper end and a lower end;   an outer sleeve including an upper end and a lower end, the outer sleeve slidably received around the inner shaft;   a first spring including a first end and a second end;   a second spring including a first end and a second end;   wherein the first spring is connected to the upper end of the outer sleeve and the second spring is connected to the lower end of the outer sleeve;   wherein when the lower end of the inner shaft is connected to the percussion mechanism, and the first spring and the second spring limit the vibration transferred to the outer sleeve from the percussion mechanism.   
     
     
         2 . The isolator apparatus of  claim 1 , wherein the first spring and the second spring are slidably received around the inner shaft. 
     
     
         3 . The isolator apparatus of  claim 1 , further comprising:
 an upper cap connected to the upper end of the inner shaft and the first end of the first spring; and   a lower cap connected to the lower end of the inner shaft and the second end of the second spring.   
     
     
         4 . The vibration isolator apparatus of  claim 3  further comprising an air hose connected to the upper cap. 
     
     
         5 . The vibration isolator apparatus of  claim 1 , further comprising:
 an upper bushing connected to the upper end of the outer sleeve and the second end of the first spring; and   a lower bushing connected to the lower end of the outer sleeve and the first end of the second spring.   
     
     
         6 . The vibration isolator apparatus of  claim 1  further comprising an actuator handle including a trigger and an air compressor connector; wherein a force applied to the trigger causes the air compressor connector to release an airflow. 
     
     
         7 . The vibration isolator apparatus of  claim 1  further comprising an upper bellows and a lower bellows, the upper bellows slidingly received around the first spring and the lower bellows slidingly received around the second spring. 
     
     
         8 . The vibration isolator apparatus of  claim 1  wherein the first spring and the second spring are compression springs. 
     
     
         9 . The vibration isolator apparatus of  claim 1  wherein the inner shaft is hollow and has a circular cross section. 
     
     
         10 . The vibration isolator apparatus of  claim 1  wherein the outer sleeve is hollow and has a circular cross section. 
     
     
         11 . A pneumatic percussion mechanism comprising:
 a percussion shaft including a first end and second end, the first end receiving an airflow;   a compaction assembly including a ram head and a compaction rod, the compaction assembly slidingly received in the percussion shaft and defining a first air space and a second air space within the percussion shaft;   a valve assembly;   a first elbow connected to the valve assembly;   a second elbow connected to the percussion shaft and the second air space; and   an air conduit connected to the first elbow and second elbow;   wherein valve assembly alternates the direction of the airflow between a first flow path and a second flow path, the first flow path connected to the first air space and the second flow path connected to the second air space, the second flow path defined by the first elbow, air conduit, and second elbow;   wherein when the airflow is directed through the first flow path the first air space expands, the second air space shrinks, and the ram head moves downward in the percussion shaft; and   wherein when the airflow is directed through the second flow path the second air space expands, the first air space shrinks, and the ram head moves upward in the percussion shaft.   
     
     
         12 . The pneumatic percussion mechanism of  claim 11  wherein the valve assembly further comprises a valve disc the alternatively obstructs access to the first flow path and the second flow path. 
     
     
         13 . The pneumatic percussion mechanism of  claim 1  further comprising a shoe connected to the compaction rod and transferring the cyclical percussion motion to the ground. 
     
     
         14 . The pneumatic percussion mechanism of  claim 11  wherein the air conduit is at least partially made of a flexible material. 
     
     
         15 . The pneumatic percussion mechanism of  claim 11  wherein the percussion shaft further comprises an upper relief hole, the upper relief hole permits the airflow to move from the first air space to the relief air space. 
     
     
         16 . The pneumatic percussion mechanism of  claim 11  wherein the percussion shaft further comprises a lower relief hole, the lower relief hole permits the airflow to move from the second air space to the relief air space. 
     
     
         17 . The pneumatic percussion mechanism of  claim 11 , further comprising a shroud around the percussion shaft. 
     
     
         18 . A tamper comprising:
 a inner shaft including an upper end and a lower end;   an outer sleeve including an upper end and a lower end, the outer sleeve slidably received around the inner shaft;   a first spring including a first end and a second end;   a second spring including a first end and a second end;   a percussion shaft including a first end and second end, the first end receiving an airflow;   a compaction assembly including a ram head and a compaction rod, the compaction assembly slidingly received in the percussion shaft and defining a first air space and a second air space within the percussion shaft;   a valve assembly;   a first elbow connected to the valve assembly;   a second elbow connected to the percussion shaft and the second air space; and   an air conduit connected to the first elbow and second elbow;   wherein when the lower end of the of the inner shaft is connected to the percussion shaft, and the first spring and the second spring limit the vibration transferred to the outer sleeve from the percussion shaft.   
     
     
         19 . The tamper of  claim 18 , wherein:
 the valve assembly alternates the direction of the airflow between a first flow path and a second flow path, the first flow path connected to the first air space and the second flow path connected to the second air space, the second flow path defined by the first elbow, air conduit, and second elbow; and   when the airflow is directed through the first flow path the first air space expands, the second air space shrinks, and the ram head moves downward in the percussion shaft, and when the airflow is directed through the second flow path the second air space expands, the first air space shrinks, and the ram head moves upward in the percussion shaft.   
     
     
         20 . The tamper of  claim 18 , wherein the percussion shaft further comprises an upper relief hole and a lower relief hole, the upper relief hole permitting airflow from the first air space to the relief air space and the lower relief hole allowing airflow form the second air space to the relief air space.