Belt saw machine with a belt cutter that is easy to replace

A belt saw machine comprising:

• an upright base frame having upper and lower frame portions;
• a cutter unit including an upper drive roller, a lower drive roller mounted rotatably to said lower frame portion, and an endless belt cutter trained on said upper and lower drive rollers;
• a roller mounting arm pivoted to said upper frame portion and having said upper drive roller mounted rotatably thereon;
• a biasing unit acting on said roller mounting arm for pivoting said roller mounting arm from a belt-slackening position, where said belt cutter is loosely held on said upper and lower drive rollers, to a belt-tightening position, where said upper drive roller is moved away from said lower drive roller so as to hold said belt cutter tightly between said upper and lower drive rollers;
• and
• a pushing unit mounted movably on said upper frame portion and operable so as to apply a pushing force on said roller mounting arm for moving said roller mounting arm from the belt-tightening position to the belt-slackening position against action of said biasing unit.