Procedure and apparatus for drafting at least one fiber band

Abstract

Proposed is a procedure and an apparatus for the drafting of at least one fiber band by means of a controlled preparatory drafting operation for a spinning machine, in particular a carding or a drafting frame, which possesses successively arranged roll-pairs ( 5, 6, 7 ) for corrective drafting, whereby the cross-section or the bulk, or the thickness of the at least one fiber band, or drafting from standard measurements is measured upstream of a roll-pair ( 5, 6, 7 ) and, based upon the corresponding measurement signals, the speed of rotation of at least one roll ( 5 a ) of a first roll-pair ( 5 ) is controlled by a first control circuit ( 30 ) and the rotational speed of at least one roll ( 6 a ) of a second roll-pair ( 6 ) is controlled by a second control circuit ( 35; 40 ). The procedure characterizes itself in that at least some of the measurement signals are so apportioned in partial amplitudes, that it is possible to form the total amplitude of the respective signal, and that band variations in a partial amplitude in the first control system ( 30 ) and variations in another partial amplitude in the second control system ( 35; 40 ) can be compensated. Likewise a corresponding apparatus is proposed.

1 . A procedure for the drafting of at least one fiber band (FB) by means of a controlled preparatory machine for a spinning works, in particular a carding machine or a drafting frame, which possesses successively aligned drafting control roll-pairs ( 5 ,  6 ,  7 ), whereby the cross-section, the bulk or the thickness of the at least one fiber band (FB) or the variation of one of these said measurement values upstream of the roll-pairs ( 5 ,  6 ,  7 ) is measured and based on the corresponding measurement signal the rotational speed of at least one roll ( 5   a ) of a first roll-pair ( 5 ) is controlled by a first control circuit ( 30 ) and the rotational speed of at least one roll ( 6   a ) of a second roll-pair ( 6 ) is controlled by a second control circuit ( 35 :  40 ), therein characterized, 
 in that at least some of the measurement signals are apportioned in such a manner into signals of partial amplitudes. which when summed, form the total amplitude of the current measurement signal, and    in that a given part of band variations can be compensated in one apportioned part of the total amplitude in a first control circuit ( 30 ) and a remaining part can be compensated in a remaining apportioned part of the total amplitude in a second control circuit ( 35 :  40 ).    
   
   
       2 - 33 . (canceled)