A METHOD AND A SYSTEM FOR CONTROLLING CIRCUMFERENTIAL WRAPPING OF A CYLINDRICAL BALE IN A BALE FORMING CHAMBER OF A BALER, AND A BALER AND A METHOD FOR PRODUCING A CIRCUMFERENTIALLY WRAPPED BALE
A fixed chamber baler (1) having a bale forming chamber (12) within which a bale (2) of silage is formed and circumferentially wrapped with wrapping film (3) comprises a system for controlling the degree of stretch in the feed direction of the wrapping film (3) with which the bale (2) is wrapped. The system comprises a first rotary encoder (51) for monitoring the rotational speed of a bale rotating roller (18e) of the baler (1), and a second rotary encoder (54) for monitoring the rotational speed of a tensioning roller (32) for tensioning the wrapping film (3). A microprocessor (56) from signals read from the first and second rotary encoders (51,54) computes the ratio of the difference of the linear speeds of the wrapping film (3) adjacent the rotating bale (2) and the tensioning roller (32) to the linear speed of the wrapping film (3) adjacent the tensioning roller (32), which is the value of the degree of stretch being induced in the wrapping film (3) as it is being wrapped onto the bale (2). A torsional load applied to the tensioning roller (32) is varied for varying the rotational speed of the tensioning roller (32) until the degree of stretch with which the wrapping film (3) is being applied to the rotating bale (2) equals a predefined degree of stretch stored in the microprocessor (56).
