Shed-forming device

Abstract

The disclosure concerns a shed-forming device including a jacquard device in which the heddles, are connected to a pull-back element, for exerting a downward force on the heddle, wherein for each heddle, a yarn tensioning element is provided to change the yarn tension in at least one associated warp thread, and where a control or steering unit is provided for steering or controlling the yarn tension in at least one associated warp thread, separately for each heddle, in order to bring the total downward force on the heddle to a specific value or vary this according to a specific profile.

In the claims: 
     
         1 . Shed-forming device comprising a jacquard device with a number of heddles, for positioning at least one associated warp thread, wherein each heddle is connected to a pull-back element, for exerting a downward force on the heddle, wherein the shed-forming device comprises, per heddle, a yarn tensioning element which is provided to change the yarn tension in at least one associated warp thread, and that the shed-forming device comprises a control or steering unit which is provided, in cooperation with the respective yarn tensioning elements, for steering or controlling the yarn tension in at least one associated warp thread, separately for each heddle, such that the total downward force on the heddle, is brought to a specific value or varies according to a specific profile. 
     
     
         2 . Shed-forming device according to  claim 1 , wherein each yarn tensioning element comprises a roller which is driven by a motor and which is in contact with at least one warp thread, and which is intended to rotate in the one or the other direction of rotation in order to move said warp thread in a direction opposite the feed direction of the warp threads, or to move the warp thread or to move with the movement thereof or to facilitate the movement thereof in a direction which is the same as the feed direction of the warp threads, in order to increase or decrease respectively the yarn tension in said warp thread. 
     
     
         3 . Shed-forming device according to  claim 1 , wherein that parameters of the jacquard device or of a weaving machine cooperating with the jacquard device, or data or parameters connected with the weaving pattern, are made available to the control or steering unit in order to be taken into account in determining the target value for the total downward force. 
     
     
         4 . Shed-forming device according to  claim 1 , wherein it comprises a storage unit in which two or more reference yarn tension profiles and/or two or more reference series of at least one reference value for the yarn tension are stored, and that the control or steering unit is provided to select a reference profile or reference series from this collection in order to use these as target value(s) or a succession of target values for steering or control. 
     
     
         5 . Shed-forming device according to  claim 1 , wherein the pull-back elements are springs.