Band saw machine capable of regulating band-saw tension

A band saw machine comprising:

• a working bench having a driving-wheel holder and a driven-wheel holder relative to the driving-wheel holder, the driven-wheel holder having a slot;
• a motor mounted to the working bench and having a rotary shaft;
• a driving wheel mounted inside the driving-wheel holder of the working bench and connected with the rotary shaft for making the driving wheel be driven by the motor for rotation;
• a driven wheel rotatably mounted inside the driven-wheel holder of the Working bench;
• a band saw running on the driving wheel and the driven wheel;
• a tension regulation device having a slide member, a hydraulic cylinder, a storage member, and an oil tube, the slide member being slidably mounted in the slot of the driven-wheel holder and connected with the driven wheel, the hydraulic cylinder having a cylinder body and a piston rod, the cylinder body being fixed to the driven-wheel holder, the piston rod having two ends, one of which is mounted to the cylinder body and the other pushes against the slide member, the oil tube being connected with the storage member and the cylinder body for supplying the hydraulic oil to the cylinder from the storage member;
• a force sensor mounted between the slide member and the piston end of the hydraulic cylinder for sensing the tension of the band saw and emitting a sensing signal;
• and
• a control system connected with the storage member and the force sensor for receiving the sensing signal from the force sensor and controllably making the storage member supply the hydraulic oil to the cylinder body of the hydraulic cylinder according to the sensing signal to elongate the piston rod.