New Technology For Woven Ropes


U
p until now, ropes have been manufactured exclusively on braiding machines. However, with
a revolutionary method from Switzerland-based narrow weaving machinery manufacturer Jakob Müller
AG, Frick, rope-like structures can now be produced on new narrow fabric needlelooms. The
differences from conventional machines relate to the reed, the fabric guide and the take-off.

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Figure 1: Jakob Müller’s NG3M narrow fabric loom, shown here, and its sister model NC2M
feature MultiSphere technology for weaving ropes, twine and other such products.


Woven Fabrics

With A Circular Cross-Section

Using Jakob Müller’s MultiSphere technology, ropes – with or without cores – and twine and
other such products can be woven on the new NC2M and NG3M narrow fabric needle looms
(See Figure 1). “M” stands for “MultiSphere.”

Compared to the braiding process, this innovative technology facilitates the cheaper
manufacture of ropes and twine with similar and frequently enhanced mechanical characteristics.
Among the related advantages are high productivity; longer, knot-free lengths; and the avoidance of
layer slippage in the case of core ropes. MultiSphere technology also allows narrow fabric
producers to enlarge their product portfolios and achieve higher production at reduced cost.

The ropes and twine produced can be used in the clothing sector as cord, laces and
shoelaces; in the sports segment as important components for water sports; for camping; and in the
construction, agriculture and horticulture industries; among other sectors. Rope- or twine-like
products also are used as cord, wallpaper edging or drawstrings for blinds. Clotheslines, dog leads
and gift string constitute another group of possible applications.


The Technology

MultiSphere machines are based on proven narrow fabric weaving technology that is used
worldwide. The machines are characterized by robustness and high production speeds, and are
designed for a variety of rope diameters. The NG3M is recommended for diameters of 1 to 7
millimeters (mm), and the NC2M for diameters of 6 mm and above. Machine operation is
straightforward and can be completed by persons familiar with narrow fabric looms. Suitable aids
are available for the creation of chains for pattern control and product development. In the case
of simpler structures, curved cam plates can be utilized for heddle control, which provides
increased production speeds. The warp threads can be taken off bobbins from a creel or via standard
warp beams. Special solutions are also possible with regard to product laying or winding.

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Figure 2: Inner and outer layers of multilayered ropes can be linked by means of weft
threads, thus preventing slippage


The Needle Looms

The idea of weaving ropes on a needle loom necessitated the redesign of a number of
components in order to ensure that the rope receives a 3-D form and can be taken off without
slippage. In addition, in order to accommodate this 3-D form, the shed opening had to be as large
as possible. For the weaving of ropes, the new narrow fabric looms differ from conventional
machines with regard to the reed, the fabric guides and fabric take-off.

As a rule, coarse reeds are used in order to attain a round rope form. Only two pitches are
required for weft beat-on; while the large shed opening necessitates the use of reeds with
increased headroom.

The standard guides in a narrow fabric needle loom have the task of holding the fabric as
steady as possible during reed beat-up. As a rule, the fabric holder is flat and exerts a certain
degree of pressure on the fabric in the formation zone. The newly developed and patented fabric
holder supports the formation of the 3-D rope structure and guarantees the precise guidance of the
rope weave.

Fabric take-off is completed by means of enlarged rollers, whereby multiple winding is
utilized to increase the winding angle. In combination with a roller coating that offers an
increased blocking coefficient, this process provides constant take-off force.

The feeding of sheath and core threads takes place via a compensation device, which also
supports the creation of a 3-D form.

Various fabric patterns are used to achieve rope-like structures with specific stress-strain
and surface characteristics. As a result of the fabric texture, linkage between the individual
layers of the rope-like structure can be attained, thus preventing dangerous slippage when the rope
is stretched over sharp edges
(See Figure 2).


The Advantages

Production of the new wovens offers several important advantages:

  • Productivity is improved. With six heads, a speed of 2,000 revolutions per minute is reached,
    and 10,000 meters of rope can be manufactured in three shifts. A comparable braiding machine
    produces 1,580 meters.
  • Longer, knot-free items are produced because longer yarn lengths are available on the bobbins
    and warp beams compared to braiding bobbins. 
  • The linkage of the various layers by means of weft threads rules out slippage in multilayered
    ropes.
  • Good mechanical characteristics include lower strength at 1 and 2 mm while meeting the German
    Institute for Standardization requirements, comparable strength between 3 and 4 mm, far higher
    strength than braided structures at a thickness of 5 mm and above, and stress-strain curve similar
    to that found in braided ropes.
  • Various surface structures are possible through the selection of differing fabric
    patterns.
  • Production and manufacturing costs are far lower than for braided ropes.

In addition to the mechanical and surface characteristics that can be attained, a reduction
in production costs constitutes an important criterion for an investment decision. The first narrow
fabric looms are already in industrial production.


Editor’s Note: Dr. Roland Seidl is headmaster at the Jakob Müller Institute of Narrow Fabrics,
Frick, Switzerland.

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