Band-clamping driving and reversing structure for baler

The utility model relates to a clamping and holding structure for the strap feeding and the strap unthreading of a baler. A roller seat body is respectively penetrated with a drive shaft and a main shaft inside, wherein, one end of the drive shaft is connected with a driving wheel; one end of the main shaft is sheathed with a driven wheel; the other end of the main shaft is penetrated with and fixed with an L-shaped connecting rod by screws in radial direction; a screw rod and an electromagnetic switch can be respectively fixed on an L-shaped supporting plate by the screws, wherein, a spring is connected between the top margin of the screw rod and the L-shaped connecting rod; the top margin of the electromagnetic switch is connected with a frame board at the side end of the L-shaped connecting rod by the screw rod. Gap distance between the driven wheel and the driving wheel can be regulated and controlled downwards via the electromagnetic attraction force of the electromagnetic switch to obtain the efficiency that a bailing strap needs large clamping and holding force of an upper and a lower rollers when the bailing strap is unthreaded.