Device for tightening strapping bands

Device (10) for tightening strapping bands (11), in particular of plastics, with an abutment (24) and with a tensioning wheel (21) provided with a return stop driven by a tensioning motor (20) by means of a gearing (31), which wheel forms a tensioning channel (26) with the abutment (24) for the band ends (11a and 11b) to be tightened and is arranged in a gearing block (18) with the tensioning motor (20) and the gearing (31) which is, as a whole, pivotally mounted around a first stationary axis (17) in the base frame (13) of the device (10) and which is held by holding means which are mounted with friction on a tensioning wheel pin (43) in its ineffective position lifted from the band end (11b) and is pivoted against the abutment (24) under the action of a (second) pressure element (64) when the tensioning wheel (21) starts in the tensioning direction (29) and the holding means loses its effective position, characterised in that the tensioning wheel (21) can be driven by the tensioning motor (20) in the tensioning direction (29) and in the opposite direction (30) and that the return stop is a (second) freewheel (57) with brake (58) which blocks the reverse rotation of the tensioning wheel (21) when the tensioning motor (20) stops, but which allows a reverse rotation of the tensioning wheel (21) when the tensioning motor reverses, and that the tensioning wheel (21) is mounted rotatably with its tensioning wheel pin (43) in an eccentric (45) with friction, which in turn is guided rotatably in a steering lever (47) which is pivotally mounted on a second stationary axis (48) on the base frame (13) and that a (first) freewheel (46) is arranged against the tensioning direction (29) between the tensioning wheel pin (43) and the eccentric (45).