| 摘要 |
A device for the automatic formation and sewing of a hem at a continuous edge of an opening of variable width in a workpiece, a hem-forming device on a sewing machine which is controlled by a logic device. An actual force acting upon a guide body is compared with at least one desired force preselectably stored in the logic device. In the event of a difference between these forces, an adjusting device actuates the guide body, serving as a cloth tensioner, until an actual force corresponding to the desired force is established on the guide body.
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