Method of cutting off workpiece using band saw machine as well as band saw machine

Abstract

A cutting-off method whereby is disclosed, whereby when a workpiece is intended to be cut off by use of an endless band saw blade suspended between a driving wheel and a driven wheel, the workpiece is cut off by imparting to the driving wheel a forced oscillation so that a phase of a longitudinal oscillation which occurs to the bandsaw blade near the driving wheel is substantially inverted to a phase of a longitudinal oscillation which occurs to the bandsaw blade near the driven wheel.

What is claimed is: 
     
         1 . A method of cutting off a workpiece using an endless band saw blade suspended between a driving wheel and a driven wheel, comprising:
 imparting to the bandsaw blade a forced oscillation so that a phase of a longitudinal oscillation which occurs to the bandsaw blade near the driving wheel is substantially inverted to a phase of a longitudinal oscillation which occurs to the band saw blade near the driven wheel.   
     
     
         2 . The method of cutting off a workpiece according to  claim 1 , wherein pulses with a frequency not less than a characteristic frequency of the bandsaw blade supporting system are applied to a motor for driving a driving wheel so as to impart to the bandsaw blade a forced oscillation. 
     
     
         3 . The method of cutting off a workpiece according to  claim 1 , wherein the forced oscillation occurs in a main-component-force direction of the bandsaw blade. 
     
     
         4 . The method of cutting off a workpiece according to  claim 1 , wherein the forced oscillation is imparted to at least one of the driving wheel and the driven wheel so that a phase of an oscillation of the driving wheel in its rotational direction is substantially inverted to a phase of an oscillation of the driven wheel in its rotational direction. 
     
     
         5 . The method of cutting off a workpiece according to  claim 1 , wherein the ratio between the amplitude of the oscillation in the bandsaw blade near the driving wheel and the amplitude of the oscillation in the band saw blade near the driven wheel is approximately equal to one. 
     
     
         6 . The method of cutting off a workpiece according to  claim 1 , wherein a node is generated in the oscillation in the bandsaw blade near a center of the width of the workpiece being cut. 
     
     
         7 . A bandsaw machine for cutting off a workpiece using an endless band saw blade suspended between a driving wheel and a driven wheel, comprising:
 an imparter to impart to the bandsaw blade a forced oscillation so that a phase of a longitudinal oscillation which occurs to the bandsaw blade near the driving wheel is substantially inverted to a phase of a longitudinal oscillation which occurs to the band saw blade near the driven wheel, and wherein the imparter includes a motor for driving a driving wheel or brakes for restraining rotation of the driving wheel or driven wheel.   
     
     
         8 . The bandsaw machine according to  claim 7 , wherein pulses with a frequency not less than a characteristic frequency of the bandsaw blade supporting system are applied to the motor for driving a driving wheel so as to impart to the bandsaw blade a forced oscillation. 
     
     
         9 . The bandsaw machine according to  claim 7 , wherein the forced oscillation occurs in a main-component-force direction of the bandsaw blade. 
     
     
         10 . The bandsaw machine according to  claim 7 , wherein the forced oscillation is imparted to at least one of the driving wheel and the driven wheel so that a phase of an oscillation of the driving wheel in its rotational direction is substantially inverted to a phase of an oscillation of the driven wheel in its rotational direction. 
     
     
         11 . The bandsaw machine according to  claim 7 , wherein the ratio between the amplitude of the oscillation in the bandsaw blade near the driving wheel and the amplitude of the oscillation in the band saw blade near the driven wheel is approximately equal to one. 
     
     
         12 . The bandsaw machine according to  claim 7 , wherein a node is generated in the oscillation in the bandsaw blade near a center of the width of the workpiece being cut. 
     
     
         13 . A bandsaw machine for cutting off a workpiece, comprising:
 an endless bandsaw blade suspended between a driving wheel and a driven wheel; and   a motor for driving the driving wheel,   wherein pulses with a frequency not less than a characteristic frequency of the bandsaw blade supporting system are applied to the motor for driving a driving wheel so as to cause oscillation in the band saw blade in a longitudinal direction.   
     
     
         14 . The bandsaw machine according to  claim 13 , wherein a phase of the oscillation in the band saw blade near the driving wheel is substantially inverted to a phase of an oscillation in the band saw blade near the driven wheel. 
     
     
         15 . The bandsaw machine according to  claim 13 , wherein the ratio between the amplitude of the oscillation in the bandsaw blade near the driving wheel and the amplitude of the oscillation in the band saw blade near the driven wheel is approximately equal to one. 
     
     
         16 . The bandsaw machine according to  claim 13 , wherein a node is generated in the oscillation in the bandsaw blade near a center of the width of the workpiece being cut. 
     
     
         17 . A method of cutting off a workpiece using a bandsaw blade suspended between a driving wheel and a driven wheel, comprising:
 applying pulses, with a frequency not less than a characteristic frequency of the bandsaw blade supporting system, to a motor for driving the driving wheel to cause oscillation in the band saw blade in a longitudinal direction.   
     
     
         18 . The method of cutting off a workpiece according to  claim 17 , wherein a phase of the oscillation in the band saw blade near the driving wheel is substantially inverted to a phase of an oscillation in the band saw blade near the driven wheel.