| 摘要 |
A universal electronic tensioner (30; 130; 230; 430; 530) for measuring and controlling with precision the tension (T, T1) of an advancing yarn (31), comprising: a plurality of fixed guides (56a-56c) and movable guides (51 a-51 d) arranged one after the other for engaging the yarn (31) and deflecting it as it advances through the tensioner (30); a movable member (33), mounted rotatingly about a fixed structure (32) and upon which are mounted the movable guides (51 a-51 d); an electromagnetic rotating actuator (34; 434) or "voice coil", connected to the movable member (33); and an electronic control unit (36) suitable for supplying the rotating actuator (34; 434) with a given electrical current (I) for exerting on the movable member (33) an electromagnetic force (F, C; C1; C2; C3) that is dependent on the electrical current (I) supplied; wherein the entity of this electromagnetic force (F, C; C2; C3) can be compensated, either by varying the electrical current (I), as a function of the angular position assumed by the movable member (33), or by providing a special structure for the electromagnetic rotating actuator (434), so as to maintain the tension (T1) of the yarn exiting from the tensioner constantly conforming over time to a prefixed value (T1 pref), freely selectable by an operator. According to one particularly advantageous embodiment, the movable guides of the tensioner (30; 130; 430) preferably include a movable guide (51 d), arranged at one end of the movable member (33), for releasing the yarn (31) at the tensioner exit point, in a direction tangential to the axis of rotation (35) of the movable member (33). This tensioner (30) is extremely compact and inexpensive to produce, and is particularly suitable for application, one per each yarn, on a warping creel (92), for the purpose of programming and controlling with great precision the tension of each single yarn fed from the creel. |
