Mechanical transmission device capable of being adjusted

The utility model discloses an adjustable mechanical transmission device which comprises a rotating shaft and a base, a first belt pulley is fixedly installed on the rotating shaft, a second belt pulley and a third belt pulley are arranged on the rotating shaft, an adjusting frame is arranged on the base, and a support and a lifting structure are fixedly installed on the adjusting frame. A drivingwheel is arranged on the support, and a tensioning wheel used for adjusting the tightness degree is arranged on the lifting structure. According to the mechanical transmission device capable of beingadjusted, due to the fact that the multiple belt pulleys are arranged and used in cooperation with the adjusting frame capable of being adjusted, different belt pulleys can be conveniently selected for installation according to needs, the transmission ratio can be conveniently adjusted, a lifting structure is adopted, and the tensioning degree can be adjusted according to different belts; meanwhile, the belt pulley can be