Spring system for feeder rollers in forage harvesters

A spring system for the upper feeder rollers in forage harvesters, in particular in a feeder device on a self-propelled forage harvester, with at least one prepressing roller and a pressing roller, which are fixed opposite two lower feeder rollers which are arranged at fixed positions in a casing of the feeder device so that a distance can be varied, where the prepressing roller and the pressing roller with a set of compression springs, the upper ends of which abut with the casing of the feeder device and a lower end of the compression springs abut on the bearing points for the prepressing roller and the pressing roller are pressed in the direction of the lower feeder rollers, on which the compression springs are arranged concentrically around the guide rods, which with their lower ends are joined to the bearing points of the prepressing roller and of the pressing roller and are fixed with their upper ends to the casing of the feeder device so that the can slide freely, comprising:

• a. at each bearing point of the prepressing roller in its lowest position the compression spring, which is already under a slight prestress, touches and only from a somewhat raised position of the prepressing roller a second compression spring is arranged for producing a common roll force;
• and
• b. at each bearing point of the pressing roller only one compression spring touches, which in its lowest position is likewise under a slight prestress and its roll force is distinctly lower than the common roll force exerted upon the bearing points of the prepressing roller.