1. Field of the Invention
The present invention relates to a band saw machine, and more particularly to a band saw machine with a rod having an adjustable position to accommodate various sized workpieces.
2. Description of the Prior Art
FIG. 1 shows a conventional band saw machine which comprises a saw frame 10, and a band saw 11 which rotatably disposed on the saw frame 10 and can be moved up and down by a quick lifting device 12. In order to detect and control the distance between the saw frame 10 and the workpiece A during cutting process, a quick lifting rod 13 is provided on the saw frame 10, so that, when the saw frame 10 moves down until the quick lifting rod 13 comes into contact with the workpiece A, the workpiece A will push the quick lifting rod 13 upward to trigger a limit switch (not shown), so as to slow down the saw frame 10, and make it ready for follow-up cutting operation.
The position of the quick lifting rod 13 on the saw frame 10 is normally fixed, therefore, the size of the workpieces to be cut will be limited to a certain range, beyond which, the quick lifting rod 13 won't be able to detect the status of the workpiece, which consequently affects the follow-up cutting operation. Besides, in order to stabilize the band saw 11, the band saw machine is usually provided with clamp rollers at both sides of the quick lifting rod 13 to clamp the band saw 11. However, when the workpiece to be clamped is relatively small, interference with the quick lifting rod 13 or the clamp rollers might be produced, or the clamp rollers are unable to stay close to the band saw 11 where the small workpiece is located, which causes wobbling of the band saw 11, adversely affecting the precision of cutting.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.