Strapping apparatus

1. A strapping head for an apparatus for strapping objects, the strapping head comprising:

a first roller, a second roller, and a third roller configurable to transmit an advancement movement, a retraction movement, and a tensioning movement to a strapping band received in the strapping head;

a first drive device operatively connected to at least one of the first and second rollers and configured to rotate the at least one of the first and second rollers about a rotational axis to cause the advancement movement, the retraction movement, and the tensioning movement,

a second drive device operatively connected to the third roller and configured to move the third roller relative to the first and second rollers from a first position in which the first roller and the third roller contact opposing sides of the strapping band to transmit the advancement movement and the retraction movement to the strapping band to a second position in which the second roller and the third roller contact opposing sides of the strapping band to transmit the tensioning movement to the strapping band; and

a controller operatively connected to the second drive device and configured to, independent of operation of the first drive device, control the second drive device to initiate movement of the third roller from the first position to the second position.

2. The strapping head of claim 1 , wherein the third roller is pivotable from the first position to the second position.

3. The strapping head of claim 2 , wherein the third roller is freely rotatable about its axis of rotation.

4. The strapping head of claim 1 , wherein the second roller is a tensioning roller of a tensioning device and the first roller is a band advancement/retraction roller of a band advancement/retraction device, wherein the first drive device is operatively connected to the tensioning and the band advancement/retraction rollers and configured to rotationally drive the tensioning and the band advancement/retraction rollers.

5. A strapping head for an apparatus for strapping an object, the strapping head comprising:

a band advancement device configured to advance a strapping band received in the strapping head during formation of a band loop;

a band retraction device configured to retract the strapping band after formation of the band loop to cause the strapping band to be laid against the object;

a common advancement/retraction roller for the band advancement device and the band retraction device;

a tensioning device configured to increase a band tension in the strapping band laid against the object, the tensioning device including a tensioning roller;

a motor operably connected to the advancement/retraction roller to drive the advancement/retraction roller in two different rotational directions and also operably connected to the tensioning roller to drive the tensioning roller in at least one rotational direction;

a third roller movable between a first position adjacent the tensioning device and a second position adjacent the band advancement device and the band retraction device;

a drive device operatively connected to the third roller and configured to move the third roller from the second position to the first position; and

a controller operatively connected to the drive device and configured to, independent of operation of the motor, control the drive device to initiate movement of the third roller from the first position to the second position.

6. The strapping head of claim 5 , wherein when in the first position, the third roller is operable with the tensioning device to perform a function of the tensioning device, and when in the second position, the third roller is operable with the band advancement device to perform a function of the band advancement device or with the band retraction device to perform a function of the band advancement device or the band retraction device.

7. The strapping head of claim 5 , wherein the third roller is pivotable between the first and the second positions.

8. The strapping head of claim 7 , wherein the third roller performs an eccentric movement along with the pivoting movement when moving between the first and second positions.

9. The strapping head of claim 3 , wherein the motor is the only motor operably connected the advancement/retraction roller and the tensioning roller and configured to drive each of the advancement/retraction roller and the tensioning roller.

10. A strapping device for strapping an object, the strapping device comprising:

a band advancement/retraction device configured to advance a strapping band extending through the strapping device during formation of a band loop and to retract the strapping band after formation of the band loop to cause the strapping band to be laid against the object;

a tensioning device configured to increase a band tension in the strapping band laid against the object;

a roller movable between a first position adjacent the tensioning device and a second position adjacent the band advancement/retraction device;

a drive device operatively connected to the roller and configured to move the roller from the second position to the first position;

a fastening device configured to join two sections of the strapping band;

an encircling strapping channel configured to guide the strapping band; and

a controller operatively connected to the drive device and configured to, independent of operation of the band advancement/retraction device and the tensioning device, control the drive device to initiate movement of the roller from the first position to the second position.

11. The strapping head of claim 1 , wherein the first and second rollers are immovable relative to the third roller.