A self-propelled cutter has a gear assembly to provide both downward and forward force on a material to be cut. A gear assembly includes a drive input gear that engages with a transfer gear and propulsion gear engaged with the transfer gear by a lever arm. The drive gear and transfer gear are coupled and fixed to the cutter body but the propulsion gear rotates about the transfer gear via the lever arm. This gear assembly enables the propulsion gear to move as required to provide both downward and forward force on a material to be cut, such as a cast. A self-propelled cutter may have a drive input that is coupled with a drive input device, such as a crank or an electric motor. A cutter may have a first gear assembly on a first side of the cutter body and a second gear assembly on a second side.

A cutting device and method. The cutting device comprises a frame body (1), provided with: a conveying assembly (2), the conveying assembly comprising a feeding end (21), a discharging end (22), and an avoidance position (23) provided between the feeding end and the discharging end, and the conveying assembly being constructed to convey a material (5) from the feeding end to the discharging end; and a cutting assembly (3), the cutting assembly comprising a cutter (31), and the cutter being constructed to be capable of moving towards the conveying assembly to the avoidance position.