Vetter Lifting bags 1 bar (14.5 psi) - Manual (Page 5)

Page 4/15
2.4 The VETTER construction
Bags which have a cylinder shape cannot bulge on the side be-
cause the material tensions evenly. This characteristic greatly re-
duces any damage to the side wall.
Owing the extensive use of internal harnesses, bulging of the top
and bottom is avoided. The strong, multi-layer and reinforced ma-
terial avoids bag damage within the working area. The supporting
material of the lifting bag is made of ARAMIDE which is a very light
but tear-resistant artificial fibre.
The coating of the supporting material is made of NEOPRENE
which is a synthetic artificial rubber. As opposed to material rub-
ber, NEOPRENE has ideal characteristics for the lifting bag, e.g.:
9 High resistance to mineral oil and acid
9 High resistance to wear and has a long life cycle
9 Maintenance free
The flexible lifting bags mould themselves to the shape of the
load to be lifted as opposed to hydraulic and pneumatic lifting
gear with their solid positioning plates. In connection with the
very low application pressure of only 1.0 kg/cm², loads can be lif-
ted carefully.
Lifting bags, irrespective of the type, are unstable over the com-
plete lifting distance! When using just one bag it must be posi-
tioned exactly under the load‘s centre of gravity otherwise load
movement cannot be avoided.
In practise, exact positioning is not possible!
If the use of one bag cannot be avoided then positioning stability
of the load is to be ensured. However, if two bags are used and if
one bag is placed to the front part and the other bag to the rear
part of the load then the centre of gravity will always be between
the two bags.
The basic condition for a stable, different control of both bags is
the separate independent control using the corresponding dual
controller.