Belt tightness adjusting device

The utility model provides a belt tightness adjusting device which comprises a mounting plate, two belt wheels are arranged on one side of the mounting plate, a plurality of belts are connected between the two belt wheels, a rotating support is arranged above or below the belts, the middle of the rotating support is fixed to the mounting plate through a rotating shaft, and the rotating shaft is fixed to the mounting plate. A kidney-shaped hole is formed in one end of the rotating support, a tensioning wheel is connected to the kidney-shaped hole in a clamped mode, the tensioning wheel abuts against the multiple belts, the other end of the rotating support is connected with a pull rod, the pull rod is connected with an elastic spring, the other end of the elastic spring is connected with an adjusting bolt, and the connecting plate is sleeved with the adjusting bolt in a screwed mode. According to the belt tensioning device, the situation that the belt is too loose can be avoided by adjusting the tensioning whe