| 摘要 |
<p>An adjustment strap tensioning device in a strapping head for a strapping machine is disclosed, of the type comprising at least a plurality of transmission pulleys apt to impart the launch and recovery of a strap ribbon, actuated by an actuation motor (M), as well as a yielding system moving in opposition to spring means according to the tension imparted on the strap by said transmission pulleys, comprising furthermore a star-shaped wheel (24) the rotation of which is proportional to the displacement of said yielding system moving in opposition to a spring (22), said star-shaped wheel (24) comprising a plurality of equally distanced marks detectable by a sensor/transducer (26) apt to issue in correspondence a counting signal of the number of marks detected during the rotation of said star-shaped wheel (24), recovery of said strap ribbon performed by said actuation motor (M) being stopped upon reaching a preset threshold of said counting signal.</p> |
