Method and apparatus for controlling the drafting of sliver in a drawing frame

摘要

The present invention relates to a method and an apparatus for controlling the drafing of sliver in a draw frame in which sliver first travels through an advance sensing means that senses variations in the mass, then passes through a drafting means which is located after the advance sensing means and is provided with an adjustable draft, and finally travels through an after sensing means located after the drafting means which senses the mass per unit of length, whereby the draft of the drafting means is varied to compensate for variations in mass of sliver in response to the sensed variations in mass evaluated in a time-delayed manner and of the difference of the measured mass per unit length of the output and of a selectable theoretical value for the mass per unit of length. The sensings are alternately applied to a common control means through switches which predominately apply the advance sensing for control means adjusting of the drafting means and less frequently applying the after sensing to update the control.