Patent ID: 7210387

Claim:
A vertical band saw machine comprising: a base which includes a front support end, a rear support end opposite to said front support end in a longitudinal direction, and a first mount area interposed between said front and rear support ends; a worktable which is disposed to rest on said front support end and which is adapted to position a workpiece to be worked; an upright post which extends in an upright direction from said rear support end and which terminates at an upper post end; a mounting frame including a coupling end disposed to be slidably retained relative to said upright post in the upright direction, a vertical path setting end which is opposite to said coupling end in the longitudinal direction, and which is disposed over and which is spaced apart from said worktable in the upright direction, and a second mount area which is interposed between said coupling end and said vertical path setting end; lower and upper blade mounting pulleys mounted on and rotatable relative to said first and second mount areas respectively about first and second axes in an axial direction transverse to both the longitudinal direction and the upright direction; a motor provided with a motor shaft that is disposed to drive one of said upper and lower blade mounting pulleys; an endless band saw blade which is trained on said upper and lower blade mounting pulleys so as to be driven by said motor shaft, and which defines a front vertical running path that runs from said vertical path setting end down into said front support end through said worktable; a tension-equalizing guider pulley which is mounted on and which is rotatable relative to said upright post about a third axis in the axial direction, and which is trained by said endless band saw blade so as to define, in respective cooperation with said upper and lower blade mounting pulleys, upper and lower inclined side paths, said tension-equalizing guider pulley being further disposed to be retainingly movable relative to said upright post in the upright direction, and being brought into synchronized movement with said coupling end such that the ratio of lengths between the upper and lower inclined side paths is kept unchanged; and a tension adjusting member disposed to displace said coupling end along said upright post from a loosened position where said upper and lower blade mounting pulleys are closer to each other to thereby facilitate replacement of said endless band saw blade, to a tensed position where said upper and lower blade mounting pulleys are remote from each other so as to enable said endless band saw blade to be driven to run along the front vertical running path.