| 摘要 |
A braking or tension device for a moving rectilinear element, notably a textile thread, (1), includes two friction members (2, 3) between which said element passes (1), each of which is equipped with converter means, for example,, piezo-electric elements. Said converter means convert a mechanical stress into electric voltage, and inversely, electric voltage into a dimension variaton. According to the invention, the electric means for the control of the movement of the two converter means in relation to each other include a command logic (9) connected to said converter means (2, 3) by means of amplifiers (7, 8) as well as means for exploiting the electric voltage emitted by at least one of the converter means. Said exploitation means consist, for example, of a means (5) for shaping the electric signal and a comparator (6) able to compare the signal to a reference threshold. The converter means consist of piezo-electric elements on their own or in combination with electro-magnets.
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