plate 5 there is mounted a reversible blower 7 which introduces compressed air into the inner space of the bellows 6 or if reversed withdraws the air therefrom the blower 7 and the bellows 6 travel with the plates 3 4 and 5 as a unit with the associated bale 2 during the opening operation turning now to fig2 there is illustrated a bale opener with a travelling opening mechanism 8 and stationary bales 2 only one is visible the lateral guide plates 9 10 are interconnected at their upper edges by means of the roof plate 5 and remain stationary during the bale opening operation above the bale 2 there is arranged a pressing plate 11 between the pressing plate 11 and the inner face of the roof plate 5 there is arranged on air bag 12 which is made for example of a synthetic material and which is closed at all sides between the lateral walls 13 and 14 of the air bag 12 and the inner faces of the guide plates 9 and 10 elastic elements such as tension springs 15 and 16 are provided which urge the pressing plate 11 together with the air bag 12 in a direction away from the bale 2 the air bag 12 is inflatable by a blower 7 mounted on the roof plate 5 further the blower 7 pressure setting member.