Lug and Leaf Type Shaft Technical Information
What is an
Air Shaft?
Air
Shafts
are used in the manufacturing processes for fitting into a core onto
which materials such as paper, card and plastic film are wound. An
Air Shaft is designed so that, on fitting into a core, it can be
readily
expanded, thereby achieving a quick and firm attachment, it may also be
easily deflated to facilitate easy withdrawal of the shaft after
winding of product is complete. Their efficient design makes them ideal
for mounting onto bearing housings to enable the winding or unwinding
of rolls of stock material with the minimum of equipment down time. The
advantage of using an Air Shaft is its ability to grip the core,
without
damage, whilst providing a positive interface to control the web via
motors & brakes. Air Shafts are available as either Lug Type (with
bladder down the centre) or Strip Type (bladders on the periphery of
the shaft)
Lug Type Air Shafts
Lug type Air Shafts are the most popular and versatile of the types of
Air Shafts. They are available in sizes ranging from 11mm to over
300mm,
manufactured in Aluminium, Steel and Carbon Fibre where applicable.
Shafts are bespoke and manufactured to the customer’s
requirements to suit new or existing machinery. They are economical to
repair and maintain, with a wide range of spares held on-site for
immediate despatch.
Air Shaft Applications
Applications for Air Shafts generally fall into the following uses:-
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Continuous
Core
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Cantilever
Air Shaft
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Multi-Slit
Air Shaft
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| For standard unwinding
& rewinding applications. Lugs are spread apart, symmetrically
along the length of the Air Shaft body |
Ideal for Narrow slitting
or single cores. Makes handling of reels easier on changeover. |
Overlapping/meeting lugs
are used to supply continuous gripping for multi-slitting applications |
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A pair of
shafts employed in tandem winding reel alternatively.
Load on shafts are reduced by 50%, eliminating interleaving
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Construction
of Lugshaft
A Lugtype Air Shaft can be best explained as metal tube with slots cut
out of it with a sealed rubber tube inside which expands to push out
Rubber or metal lugs which grip the core. The journals are fitted in
each end of the tube to suit the machine dimensions. The diagram below
shows the general parts used in a Lugshaft:-
Leaf
Type Shafts
A leaf shaft
is recommended when thin wall cores requiring sensitive but positive
gripping are to be used. The design ensures a high level of
concentricity is maintained and core distortion kept to a minimum,
achieved by 360° gripping of the core, with the leaves being
machined to suit the core diameter when expanded.
Rimor can supply these shafts
with Aluminium or Steel leaves depending on the application.
This Leaf shaft can also used for coreless applications where there is
a requirement to wind the material directly on to the shaft. The
standard leaf shaft design is modified to incorporate a bar along the
length of the shaft to trap the web.
Design & Performance
Program
To ensure our Air Shafts
meet the customers’ requirements we instructed an external
consultancy company to compile a program to check the maximum
deflection and stress in the Air Shaft for any given parameters. The
layout below shows the various parameters that can be checked within
our program:-
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