Round balers are used to form bales from stalk-shaped agricultural harvested produce. Such round balers have a bale-forming chamber and associated pressing means. After completing and optionally wrapping a bale with mesh, twine, or a film, the bale is ejected out the back of the bale-forming chamber.
In many round balers, especially in those with a variable bale size, the bale-forming chamber is partially or completely surrounded by one or more pressing belts. The pressing belt or belts wrap around the rollers, of which at least one can be driven. Some of the rollers are supported on the frame of the round baler and others can move relative to the frame, in order to adapt the bale-forming chamber to the gradually growing bale and to allow an ejection of a completed bale.
The partially driven, partially freely co-rotating rollers extend transverse to the forward direction and to the axis of the bale. Typically, a number of narrower pressing belts is distributed across the width of the bale-forming chamber or a single, wide pressing belt is used (cf. U.S. Pat. No. 5,941,168 A1).
Because a non-uniform loading of harvested produce across the width of the bale-forming chamber or a shifting of the harvested produce toward one side while working on a hill leads to a lateral displacement of the pressing belt, which can result in undesired rubbing of the pressing belt against the side wall of the round baler and incorrect measured values of a sensor interacting with the pressing belt for detecting the bale size, guides for the pressing belt have been proposed that are made from rigid elements contacting the pressing belt on the side (U.S. Pat. No. 5,261,323 A1). It has also been proposed to attach rings that project in the radial direction on one of the rollers, so that the individual pressing belts each run between two rings (U.S. Pat. No. 3,992,987 A1). It has further been proposed to implement the lateral guidance of the belt through grooved rollers that contact the belts on the side directly before a driven roller (DE 10 2011 003 727 A1).
U.S. Pat. No. 3,687,273 A describes a conveyor belt in which the lateral position of the belt is registered by rollers contacting the belt on the side. The rollers control a holder that is supported by springs on the frame on which a deflection roller of the belt is supported, such that the belt is pre-tensioned more strongly by the deflection roller on the side toward which the belt is running. In this way, the belt should be guided centrally on the deflection roller.
The known means for the lateral guidance of pressing belts causes increased friction of the belt on the guidance means, which requires, on one hand, drive energy and, on the other hand, results in wear of the belt.