Boring machine

Abstract

In a boring machine, rotation of a motor is transferred to a pipe spindle and a shaft, a cutting edge feeding mechanism arranged side by side with the pipe spindle moves the shaft toward a workpiece and a cutting edge attached to an end of the shaft drills a hole in the workpiece. The cutting edge feeding mechanism slidably but non-rotatably supports a chain holder around an outer circumference of the pipe spindle. A sprocket wrapped around by a chain is rotated by a handle to move the shaft. The radius of rotation of the handle is reduced to slowly move the shaft. The maximum torque of the motor rotating the shaft is controlled. The number of cutting edges falls within a range from six to eight.

1 . A boring machine comprising: 
 a machine body;    a pipe spindle freely rotatably supported within the machine body;    a shaft vertically slidably supported through the pipe spindle;    a cutting edge supported at one tip of the shaft with a cutting edge mounting shaft;    a cutting edge feeding mechanism for vertically moving the shaft through the pipe spindle, the cutting edge feeding mechanism including a chain;    a motor for rotating the pipe spindle and the shaft; and    a saddle bracket arranged on a lower end of the machine body.    
   
   
       2 . The boring machine according to  claim 1 , wherein the pipe spindle is rotatably supported at a top end thereof on a needle bearing and a thrust bearing at a machine body cover of an upper portion of the machine body, and rotatably supported at a bottom end thereof on a ball bearing in a gear box secured to a lower portion of the machine body, wherein the pipe spindle comprises a pair of grooves vertically extending in symmetry with respect to the center axis of the pipe spindle and houses the shaft therewithin.  
   
   
       3 . The boring machine according to  claim 1 , wherein the shaft comprises: 
 a shaft guide received in the grooves of the pipe spindle, the shaft guide including pin guides respectively on two ends thereof, the pin guides slidably engaged with an outer circumference of the pipe spindle, and fixing the ends of a pin penetrating through a top portion of the shaft;    a pin cover arranged on an outer circumference of each of the pin guides; and    a chain holder housing the pin guides and the pin covers and being slidably supported on the outer circumference of the pipe spindle,    wherein the shaft is slidably supported at a lower end thereof within the pipe spindle.    
   
   
       4 . The boring machine according to  claim 1 , wherein the cutting edge feeding mechanism comprises: 
 a chain holder arranged side by side in a standing condition with the pipe spindle and slidably but non-rotatably supported on an outer circumference of the pipe spindle;    a chain having two ends thereof anchored to the chain holder;    a sprocket wrapped around by the chain; and    a handle for rotating the sprocket,    wherein rotation of the handle causes the sprocket to rotate, thereby moving the chain holder and the shaft.    
   
   
       5 . The boring machine according to  claim 4 , wherein the cutting edge feeding mechanism comprises: 
 the chain holder;    the chain having two ends thereof anchored to the chain holder;    a pair of upper and lower sprockets arranged to be wrapped around by the chain;    a sprocket shaft supporting the upper sprocket;    a handle shaft linked with the sprocket shaft via a gear;    a handle secured to the handle shaft;    a brake assembly housed in the handle shaft; and    a sprocket shaft supporting the lower sprocket.    
   
   
       6 . The boring machine according to  claim 5 , wherein a radius of rotation of the handle is reduced so that the shaft slowly moves.  
   
   
       7 . The boring machine according to  claim 1 , wherein the motor comprises a supporting shaft which is engaged, via a gear train in a gear box, with a first gear fixed to the pipe spindle, wherein the pipe spindle and the shaft are rotated at a reduced speed by the motor.  
   
   
       8 . The boring machine according to  claim 7 , wherein the shaft is rotated at a lower torque with the maximum torque of the motor controlled.  
   
   
       9 . (canceled)  
   
   
       10 . The boring machine according to  claim 1 , wherein the number of cutting edges to be mounted on the shaft falls within a range from six to eight.  
   
   
       11 . A boring machine comprising: 
 a machine body;    a pipe spindle freely rotatably supported within the machine body, wherein the pipe spindle is rotatably supported at a top end thereof on a needle bearing and a thrust bearing at a machine body cover of an upper portion of the machine body, and rotatably supported at a bottom end thereof on a ball bearing in a gear box secured to a lower portion of the machine body, wherein the pipe spindle includes a pair of grooves vertically extending in symmetry with respect to a center axis of the pipe spindle;    a shaft vertically slidably supported through the pipe spindle, the shaft including a shaft guide received in the grooves of the pipe spindle, the shaft guide including pin guides respectively on two ends thereof, the pin guides slidably engaged with an outer circumference of the pipe spindle, and fixing the ends of a pin penetrating through a top portion of the shaft, a pin cover arranged on an outer circumference of each of the pin guides, and a chain holder housing the pin guides and the pin covers and being slidably supported on the outer circumference of the pipe spindle, wherein the shaft is slidably supported at a lower end thereof within the pipe spindle;    a cutting edge supported at one tip of the shaft with a cutting edge mounting shaft;    a cutting edge feeding mechanism for vertically moving the shaft through the pipe spindle, the cutting edge feeding mechanism including a chain holder arranged side by side in a standing condition with the pipe spindle and slidably but non-rotatably supported on an outer circumference of the pipe spindle, a chain having two ends thereof anchored to the chain holder, a sprocket wrapped around by the chain, and a handle for rotating the sprocket, wherein rotation of the handle causes the sprocket to rotate, thereby moving the chain holder and the shaft;    a motor for rotating the pipe spindle and the shaft, wherein the motor includes a supporting shaft which is engaged, via a gear train in a gear box, with a first gear fixed to the pipe spindle, wherein the pipe spindle and the shaft are rotated at a reduced speed by the motor; and    a saddle bracket arranged on a lower end of the machine body.