Patent attributes
A vertical band saw machine includes a first transmitting shaft driven by a drive force of a motor, a second transmitting shaft journaling a lower blade mounting pulley for rotating an endless band saw blade, and a speed ratio varying device coupling the transmitting shafts. The device includes two pitch-variable first and second pulleys mounted on the transmitting shafts, a belt trained on the pulleys, and a control unit operable to move a movable disc of the second pulley toward or away from a fixed disc of the second pulley so as to vary the radial distance between the belt and each of the transmitting shafts, thereby freely varying the speed ratio of the second transmitting shaft to the first transmitting shaft so as to rotate the saw blade at a desired speed.
