Method for actuating the band driving device of a strapping machine and corresponding strapping machine

A strapping machine comprising:

• a frame;
• a strapping band guide supported by the frame;
• a shooting-and-retrieval unit supported by the frame and comprising a first drive roller and a first motor operably connected to the first drive roller to drive the first drive roller;
• a back-tensioning unit supported by the frame and comprising a second drive roller and a second motor operably connected to the second drive roller to drive the second drive roller;
• a detector configured to detect a leading end of a strapping band;
• and
• a controller configured to:
• actuate the first motor to drive the first drive roller to move the strapping band in a feed direction at a feed speed such that the leading end of the strapping band enters the strapping band guide;
• and
• responsive to the detector failing to detect the leading end of the strapping band within a designated time period following the actuation of the first motor:
• determine a retrieval time based on a designated retrieval speed and an amount of time the first motor was actuated;
• actuate the first motor to drive the first drive roller to move the strapping band in a retraction direction opposite the feed direction at the designated retrieval speed for the retrieval time such that the leading end of the strapping band is withdrawn from the shooting-and-retrieval unit;
• and
• afterwards, actuate the second motor to drive the second drive roller to move the strapping band in the feed direction such that the leading end of the strapping band is received in the shooting-and-retrieval unit.