Note: Descriptions are shown in the official language in which they were submitted.
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1
Description
Lift support means for a lift system, lift system with such a lift support
means
and method for assembling such a lift system
The present invention relates to a lift support means for a lift system, to a
lift system with
such a lift support means and to a method for assembling such a lift system.
In a lift system, one or more lift support means transmit forces from a drive
to a cage
movable in a lift shaft or along free-standing guide rails. A cage can be
coupled by way of
the same or further support lift support means to a compensating weight or
counterweight
which travels in opposite sense to the cage.
Such a lift system with a lift support means according to the introductory
part of claim 1 is
known from EP 1 446 348 B1. In an example of embodiment the lift support means
has on
a drive side five drive ribs of wedge-ribbed shape for engagement with a drive
wheel and
on a deflecting side opposite the drive side a guide rib similarly of wedge-
ribbed shape for
engagement with a deflecting wheel. Guide ribs and drive ribs engage in
corresponding
wedge-shaped grooves which are formed on deflecting and drive wheels.
A rib generally has two mutually opposite flanks which include a flank angle a
as
schematically indicated in Fig. 2. In a wedge rib these flanks are generally
inclined relative
to one another and in a rectangular rib they are parallel to one another with
a flank angle a
= 0 . In the present case the projection of the flank onto the plane spanned
by the
longitudinal and transverse direction of the lift support means is termed
flank width t. In a
rectangular rib, for example, it is equal to zero and in a wedge rib with a
flank length f the
inclined flanks are generally t = f x sin(a/2). Correspondingly, the
projection of the flank
onto the median or longitudinal plane of the base body is termed flank height
h. it
corresponds, for example, in a rectangular rib with the flank length f and in
a wedge rib is
generally h = f x cos(a/2).
Due to the wedge effect the drive ribs of wedge-ribbed shape increase, for the
same
tension force in the lift support means, the normal forces acting on the
flanks of the drive
ribs and thus the drive capability of the drive. In addition, they
advantageously guide the
lift support means in transverse direction on the drive wheel.
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The guide rib at the rear side guides the lift support means in transverse
direction on
deflecting wheels over which the lift support means is deflected so as to co-
operate with,
for example, the cage or the counterweight.
It has proved advantageous to arrange the tensile carrier arrangement at not
too wide a
distance and at a spacing from the drive side or the flanks of the drive ribs
which is as
uniform as possible so as to provide a more homogenous distribution of force
in the drive
ribs. This results in drive ribs with smaller flank height and flank width as
well as a flatter
flank angle.
The lift support means usually rests from above on a drive wheel of the lift
system so that it
is redisposed by its own weight in the grooves in the drive wheel
circumference.
Conversely, it frequently loops around deflecting wheels laterally or from
below so that its
own weight does not redispose it or even urge it out of the grooves in the
deflecting wheel
circumference. If slackening of the lift support means occurs due to, for
example, inertias
of the cage or the counterweight or oscillations in the lift support means
this can have the
consequence that a guide rib slides completely out of the associated groove in
the
deflecting wheel. Without the then absent transverse guidance on the
deflecting wheel a
diagonal tension, which is usually present in the lift system due to assembly
tolerances,
twistings of the load run and the like, has the effect that the lift support
means then
migrates in transverse direction from its desired position and the guide rib
also no longer
finds its way back into the groove in the deflecting wheel when the lift
support means
tightens again.
The lift support means usually loops around a drive wheel of the lift system
with a greater
angle of wrap than deflecting wheels so as to prevent, at the drive wheel,
slipping of the lift
support means in correspondence with the Euler-Eytelwein formula. Accordingly,
a drive
rib frequently engages over a greater angular range in a drive wheel than a
guide rib in a
deflecting wheel. In addition, in a deflecting wheel with a smaller angle of
wrap the forces
in radial direction, which constrain the rib in the groove at the wheel
circumference, are
less than in the drive wheel with greater angle of wrap. If, for example, the
lift support
means loops around a drive wheel by 1800, but a deflecting wheel by only 900,
the
resultant radial force on the lift support means is then greater at the drive
wheel by the
factor ~2 than at the deflecting wheel.
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In addition, the stronger diagonal running, which is caused by, for example,
assembly
tolerances, of the lift support means frequently occurs between adjacent
deflecting wheels.
Moreover, compensation for this by deformation of the lift support means also
cannot be
sufficiently provided due to the frequently smaller spacings between adjacent
deflecting
wheels. The diagonal tension resulting therefrom seeks to displace the lift
support means
on the deflecting wheels in transverse direction.
It is therefore the object of the present invention to improve the guidance of
a lift support
means at its deflection side.
This object is fulfilled by lift support means according to at least one
alternative of claim 1.
Claim 18 protects a lift system with such a lift support means and claim 22 a
mounting
method for such a lift system.
A lift support means according to the invention comprises a base body, a drive
side, which
is provided for friction-coupling engagement with the drive wheel of a lift
system and has at
least one drive rib, and a deflecting side, which is disposed opposite the
drive side and
which is provided for contact with a deflecting wheel of the lift system and
has at least one
guide rib. A tensile carrier arrangement is arranged in the base body for
transmission of
the tension forces.
When in the following reference is made to at least one drive rib or at least
one guide rib in
that case always several drive ribs or guide ribs can equally well be
comprehended,
wherein a feature defined for at least drive rib or guide rib then applies to
at least one of
these several drive or guide ribs, preferably for several drive and/or guide
ribs, particularly
preferably for all drive and/or guide ribs, of the support means.
According to a first embodiment of the present invention at least one,
preferably each,
guide rib now has a greater flank height than at least one, preferably each,
drive rib. This
ensures better guidance of the lift support means in transverse direction.
The flank height determines the radial displacement which the lift support
means
experiences relative to a drive or deflecting wheel before the rib exits
entirely from an
associated groove in the outer circumference of the drive or deflecting wheel
and can no
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longer guide the lift support means in transverse direction.
Through the extension of the flank height of the guide ribs relative to the
drive ribs partial
compensation can be provided for the effects illustrated in the introduction
and at the same
time a more homogenous forced distribution between the drive side and the
tensile carrier
arrangement can be realised.
The higher guide rib can, in the case of a microscopic or macroscopic
slackening of the lift
support means, move radially further away from a deflecting wheel without the
transverse
guidance being completely lost. If the lift support means tightens again, the
guide rib,
which always still enters partly into the groove of the deflecting wheel due
to its greater
flank angle, advantageously centres the lift support means again on the
deflecting roller.
In addition, the flank area, which engages in the groove in the deflecting
wheel
circumference, of the guide rib increases and can thus ensure a sufficient
transverse
guidance even with smaller deflecting angles. A greater diagonal tension up to
4% can
therefore preferably also be realised by a lift support means according to the
first
embodiment of the present invention.
Through the drive rib, which is lower by comparison, the change in spacing
and/or the
maximum spacing of the tensile carriers from the drive side can at the same
time be
reduced so that a more homogenous distribution of force in the drive rib is
achieved.
Preferably the ratio of the flank height of at least one, preferably each,
guide rib to the
flank height of at least one, preferably each, drive rib is at least 1.5,
preferably at least 2.0
and particularly preferably at least 2.5. A ratio of at least 1.5 can, for
example, be
sufficient in order to provide compensation for the deterioration in guidance
on a deflecting
wheel due to a smaller angle of wrap. A ratio of at least 2.0 can, for
example, be
advantageous in order to provide compensation for the deterioration in the
guidance on a
deflecting wheel due to the intrinsic weight which does not return the lift
support means to
its position on the deflecting wheel or even sets it away from this. A ratio
of at least 2.5
can, for example, be advantageous in order to make possible a greater diagonal
tension.
Additionally or alternatively to the greater flank height at least one,
preferably each, guide
rib can have a greater flank width than at least one, preferably each, drive
rib. This, too,
guarantees better guidance of the lift support means in transverse direction.
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The flank width determines the offset in transverse direction by which a rib
can run into a
groove or run out of this and yet is automatically guided back into the
groove, in other
words the 'capture range' within which a rib is still captured by a groove of
a drive or
deflecting wheel. Due to the fact that in accordance with the invention the
flank width of
the guide rib is greater than the flank width of the drive rib, thus the guide
rib is wider in
transverse direction, a more homogenous distribution of force in the drive rib
can be
provided in the narrower drive rib due to the resulting smaller spacing of the
tensile
carriers from the drive side, whilst the lift support means when deflected
over a deflecting
wheel at the same time has better guidance due to the wider guide rib.
This can similarly provide partial compensation for the above-explained
effects of poorer
guidance and/or stronger diagonal tension due to its intrinsic weight or a
smaller angle of
wrap at the deflecting side. In the event of microscopic or macroscopic
slackening of the
lift support means the wider guide rib can displace more strongly in
transverse direction on
a deflecting wheel without completely losing transverse guidance. When the
lift support
means tightens again the guide rib, which due to its greater flank width
always still lies
partly over the groove of the deflecting wheel, advantageously centres the
lift support
means on the deflecting roller again. In addition, the flank area, which
engages in the
groove in the deflecting wheel circumference, of the guide rib increases and
can thus
ensure sufficient transverse guidance even in the case of smaller angles of
wrap. Thus, a
greater diagonal tension can equally be realised with a lift support means in
which the
guide rib has a greater flank width than the drive rib.
The ratio of the flank width of at least one, preferably each, guide rib to
the flank width of at
least one, preferably each, drive rib is preferably at least 1.5, preferably
at least 1.75 and
particularly preferably at least 2Ø A ratio of at least 1.5, for example,
can be sufficient in
order to provide compensation for deterioration in the guidance on a
deflecting wheel due
to a smaller angle of wrap. A ratio of at least 1.75, for example, can be
advantageous to
provide compensation for deterioration in the guidance on a deflecting wheel
due to the
intrinsic weight which does not return the lift support means to its position
on the deflecting
wheel or even sets it away from this. A ratio of at least 2.0, for example,
can be
advantageous to make possible a greater diagonal tension.
The above-explained advantages of a greater flank height or flank width of the
guide rib by
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comparison with the drive rib are already self-evident. For preference,
however, the two
features are combined together so that the higher and wider guide rib can
further displace
not only in radial direction, but also in axial direction and nevertheless is
guided, especially
centred, by the guide rib on the deflecting wheel. A greater diagonal tension
can thereby
be realised at the deflecting wheel, whilst at the same time the more
homogenous
distribution of force arises due to the lower, narrower drive ribs.
According to a second embodiment of the present invention, additionally or
alternatively to
the ratio of the flank height and/or flank width of at least one guide rib to
at least one drive
rib it is provided that the ratio of the flank height of at least one,
preferably each, guide rib
to the width of the lift support means is at least 0.4, preferably at least
0.45 and particularly
preferably at least 0.5.
The wider the lift support means is formed, the more inertial mass pushes away
from the
deflecting wheel when microscopic or macroscopic slackening occurs. Wider lift
support
means also permit, due to the geometrical moment of inertia thereof, stronger
transverse
forces or a stronger diagonal tension, which equally requires better guidance
on a
deflecting wheel. It has now proved in tests that with the above-mentioned
ratios between
guide rib height and lift support means width it is possible to achieve a very
good guidance
of the lift support means on a deflecting wheel. In that case a ratio of at
least 0.4, for
example, can be sufficient to provide compensation for deterioration in the
guidance on a
deflecting wheel due to a smaller angle of wrap. A ratio of at least 0.45, for
example, can
be advantageous in order to provide compensation for deterioration in the
guidance on a
deflecting wheel due to the intrinsic weight which does not return the lift
support means to
its position on the deflecting wheel or sets it away from this. A ratio of at
least 0.5, for
example, can be advantageous in order to make possible a greater diagonal
tension.
The ratio of the flank height of at least one guide rib to the width of the
lift support means
according to the second embodiment of the present invention can be realised
independently of the ratio of the flank height or flank width of the guide rib
by comparison
with a drive rib in accordance with the first embodiment. For example, the
above-
explained advantages can result even with high and wide drive ribs in which
flank height
and/or flank width of drive and guide ribs are substantially the same.
However, the two
embodiments are preferably combined together so that not only the more
homogenous
distribution of force in the shorter and/or narrower drive ribs, but also the
better guidance
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characteristics of the high and/or wide guide ribs are achieved, wherein the
guide ribs are
adapted to the width of the lift support means.
According to a third embodiment of the present invention, additionally or
alternatively to
the ratio of the flank height and/or flank width of a guide rib to a drive rib
according to the
first embodiment and/or additionally or alternatively to the ratio of the
flank height of a
guide rib to the width of the lift support means according to the second
embodiment at
least one, preferably each, drive rib and at least one, preferably each, guide
rib is
constructed as a wedge rib with a flank angle, wherein the flank angle of at
least one,
preferably each, drive rib is greater than the flank angle of at least one,
preferably each,
guide rib.
More acute guide ribs improve the transverse guidance of the lift support
means at the
deflecting side thereof and can thus better provide compensation for, for
example, the
above-explained effects due to the intrinsic weight, a smaller angle of wrap
and/or the
greater diagonal tension. In particular, greater penetration depths are thus
provided by
comparison with rib base area without having to widen the lift support means
overall. On
the other hand, more obtuse drive ribs lead to a more homogenous distribution
of force in
the lift support means, since the spacing of the individual tensile carriers
from the drive
side is more uniform and also the maximum spacing reduces.
The ratio of the flank angle according to a third embodiment of the present
invention can
be realised independently of the features of the first or second embodiment.
For example,
the above-explained advantages can result even with shorter or narrower guide
ribs in
which the penetration depth is, nevertheless, increased relative to its base
area by the
more acute flank angle. The third embodiment is, however, preferably combined
with the
first and/or second embodiment so that the advantageous greater flank height
of the guide
rib results due to the more acute flank angle.
A flank angle between 600 and 120 , preferably between 80 and 100 and
particularly
preferably substantially equal to 90 has proved advantageous for a drive rib
constructed
as a wedge rib so as to on the one hand achieve a sufficient wedge effect and
thus
increase in the normal force and on the other hand prevent excessive area
pressure,
material loading and noise output connected therewith and a jamming of the
lift support
means.
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A flank angle between 60 and 100 , preferably between 70 and 90 and
particularly
preferably substantially equal to 80 has proved advantageous for a guide rib
constructed
as a wedge rib so as on the one hand to ensure a sufficient guidance in a
groove of a
deflecting wheel and on the other hand to avoid excessive area pressures and
the loading
of the lift support means connected therewith as well as output of noise which
occurs.
According to a fourth embodiment of the present invention it is provided,
additionally or
alternatively to the flank height and/or flank width of the guide rib
according to the first
and/or second embodiment and/or additionally or alternatively to the flank
angle of the
guide rib according to the third embodiment that a respective guide rib is
associated with
one, two or three guide ribs.
The transverse guidance on a deflecting wheel is particularly advantageous in
order to
prevent migration of the lift support means due to diagonal tension, which can
result, for
example, due to diagonal running of the lift support means between a drive
wheel and a
deflecting wheel. The diagonal tension possible between a drive wheel and a
deflecting
wheel is limited, inter alia, by the number of drive ribs guiding the lift
support means on the
drive wheel. It has proved in tests that with one guide rib for at most three,
preferably at
most two, drive ribs and particularly preferably one drive rib a particularly
reliable guidance
of the lift support means can be ensured. In addition, the lever arm between
outer drive
ribs and the associated guide rib advantageously reduces and thus the torque
which acts
on the lift support means and which results from the components of the forces,
which act
on the inclined flanks, perpendicularly to the flank width.
Advantageously the fourth embodiment is combined with the first, second and/or
third
embodiment of the present invention. In particular, if in accordance with the
first or second
embodiment a guide rib is constructed which is high and/or wide by comparison
with the
drive rib or the lift support means width and in accordance with the third
embodiment a
guide rib is constructed which is acute, advantageous guidance and lever
conditions occur
with a drive-to-guide rib ratio of at most 3:1.
A guide rib is preferably centred between two adjacent drive ribs. The
resultant of the area
load on a flank of the guide rib is then applied in statically stable manner
between the two
points of action of the resultant of the area loads on the flanks of the drive
ribs. In addition,
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the lift support means can in this manner be constructed to be particularly
slender.
According to an embodiment of the present invention the ratio of the width of
the lift
support means to the height of the lift support means is at most 0.95,
preferably at most
0.93 and particularly preferably at most 0.91.
Thus, in particular, relatively acute and/or high guide ribs can be provided,
which due to
their flank height ensure good transverse guidance of the lift support means.
Advantageously, such a slender lift support means also has a greater
geometrical moment
of inertia in transverse direction and thus is stiffer than flat belts with
respect to bending
about the transverse axis. Such a lift support means therefore experiences a
higher
degree of biasing back into the straight, underformed position when deflected
around a
drive or deflecting wheel. This biasing counteracts jamming of drive or guide
ribs of the lift
support means in associated grooves on a drive or deflecting wheel and thus
advantageously reduces the risk of jamming.
A further advantage resides in the additional volume of the lift support means
in the
direction of its height. This additional volume advantageously damps
vibrations and
diminishes shocks, which makes the running of such a belt more consistent.
The transmission of the circumferential force between tensile carriers and
drive wheel
takes place with transient deformation of the lift support means in shear. The
thus-
occurring alternating deformations lead, over the long term, to destruction of
the lift support
means and thus limit the service life thereof. Here, too, the additional
volume of the lift
support means in the direction of its height can advantageously on the one
hand reduce
the deformations in shear and on the other hand better dissipate the then-
created heat
over the greater volume and, in particular, over the greater surface area.
The drive side of the lift support means according to the invention preferably
has at most
three, preferably exactly two, drive ribs and the deflecting side exactly one
guide rib. Such
a lift support means can be of slender construction and thus realise the
advantages
explained in the foregoing.
As explained above, it is advantageous to associate one or two flanks of a
drive rib with
CA 02596726 2007-08-09
each tensile carrier so as to achieve a more homogenous distribution of force.
For this
purpose it is thus advantageous to associate one or two tensile carriers with
a drive rib. If
the drive side has only two or three drive ribs, then a tensile carrier
arrangement of two
(two drive ribs each with an associated tensile carrier) up to a maximum of
six (three drive
ribs each with two associated tensile carriers) tensile carriers thus results.
If now for
fulfilment of different tensile force requirements several lift support means
are connected in
parallel, then lift support means with only two or three drive ribs therefore
significantly
increase the modularity, because the tensile force transmissible by the
combination of
parallel lift support means can thus be graduated significantly more finely
and be adapted
to the respective requirements.
The flanks of at least one, preferably each, drive rib and/or at least one,
preferably each,
guide rib can be formed to be planar. This facilitates production and
advantageously
produces a self-centring of the rib in an associated groove due to the
inclination. Equally,
the flanks of, for example, at least one, preferably each, guide rib can also
be formed to be
concave so as to save material and at the same time achieve a large flank
height and/or
flank width. The flanks of, for example, at least one, preferably each, guide
rib can just as
well be formed to be convex so as to make available sacrificial material and
thus increase
the service life of the lift support means.
According to an embodiment of the present invention the minimum width of one
or more
drive ribs is greater than the minimum width of the associated grooves of a
drive wheel. It
can thereby be ensured that the distal flank regions of the drive ribs always
completely rest
on corresponding counter-flanks of the associated grooves, which still further
taper below
the completely penetrated drive rib. These counter-flanks thus do not exert,
in their groove
base, any notch effect on the drive ribs.
A groove with a radius is preferably formed between two adjacent drive ribs,
wherein the
ratio of this radius to a radius formed at the tip of an associated rib of the
drive wheel of
the lift system is less than one, preferably less than 0.75 and particularly
preferably less
than 0.5. It can thereby be ensured that the rib, which engages between the
two adjacent
drive ribs, of the drive wheel exerts no or only a small notch effect on the
proximal flank
regions of the drive ribs.
The base body, one or more drive ribs and/or one or more guide ribs can be of
unitary or
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multi-part construction from an elastomer, particularly polyurethane (PU),
polychloroprene
(CR), natural rubber and/or ethelene-propylene-diene rubber (EPDM). These
materials
are particularly suitable for conversion of the friction forces acting on the
drive side into
tension forces in the tensile carriers and in addition advantageously damp
vibrations of the
lift support means. The drive and/or deflecting side can have one or more
casings, for
example of textile fabric, for protection against abrasion and dynamic
destruction.
A unitary construction gives a particularly compact and homogenous lift
support means. If,
conversely, a group of one or more drive ribs is of multi-part construction
with a group of
one or more guide ribs, in that the lift support means, for example, is of two-
part
construction from a part comprising the drive ribs and a part connected
therewith and
comprising the guide ribs, different material characteristics can be provided
on the drive
side and deflecting side. For example, the drive side can have a lesser
hardness,
particularly a lesser Shore hardness, and/or a greater coefficient of friction
than the
deflecting side so as to achieve better drive capability, whereas conversely
the lower
coefficient of friction of the deflecting side reduces the energy loss during
deflection.
For this purpose, in particular, the drive side and/or the deflecting side can
additionally or
alternatively have a coating of which the coefficient of friction, hardness
and/or abrasion
resistance differs or differ from the base body. Alternatively to the coating,
a vapour
deposition or a flocking can also be provided.
Through the multi-part construction of drive and guide rib and/or the coating
of drive and/or
deflecting side a lift support means according to the present invention can
preferably have
coefficients of friction of = 0.2 to 0.6 on the drive side and/or less than
or equal to 0.3
on the deflecting side.
As explained in the foregoing, it can be advantageous for the spacing of the
tensile carrier
arrangement from the drive side to be less than from the deflecting side. A
more
homogenous distribution of force in the drive rib and at the same time a
better guidance of
the lift support means at the deflecting side can thereby be combined. In that
case, for
example, there can be defined as spacing the maximum spacing of a tensile
carrier from a
flank, the mean spacing thereof and/or the spacing of the tensile carrier from
the point of
force action of the resultant of the area load on the flank.
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The diameter of the tensile carriers is preferably in the region of 1.5 to 4
millimetres. Such
tensile carriers have a sufficient capability of bending around drive and
deflecting wheels
and on the other hand have a sufficient strength and can be readily embedded
in the base
body.
According to an embodiment of the present invention each tensile carrier of
the tensile
carrier arrangement comprises a double-ply core strand with a core wire and
two wire
layers wrapped about this, and single-ply outer strands, which are arranged
around the
core strand, with a core wire, and a wire layer wrapped around this. Such a
tensile carrier
construction, which can have, for example, one core strand with 1+ 6 + 12
steel wires and
eight outer strands with 1+ 6 steel wires, has in tests proved advantageous
with respect to
strength, ease of production and capability of bending.
Advantageously, in that case the two wire layers of the core strand have the
same angle of
wrap, whilst the one wire layer of the outer strands is wrapped against the
wrap direction
of the core strand, and the outer strands are wrapped around the core strand
opposite to
the wrap direction of their own wire layer. The tensile carrier thus has the
order SSZS or
ZZSZ. This reduces stretching of the strands.
As mentioned in the foregoing, a modular construction of a lift support means
composite of
several lift support means according to the present invention is advantageous
in order to
provide different tensile force requirements. In that case the lift support
means are guided
parallel to the drive wheel and deflecting wheel.
In this connection, two lift support means can be spaced apart by a gap. This
simplifies
mounting and allows slight deformations of the individual lift support means
without these
rubbing against one another or mutually working out of the grooves of the
drive wheel or
deflecting wheel. Advantageously for this purpose the gap is at least 3%,
preferably at
least 4% and particularly preferably at least 5% of the width of the lift
support means.
For mounting, the lift support means can be produced from a pre-product,
wherein the pre-
product consists of two or more lift support means with a one-piece base body.
The pre-
product is partly divided between drive ribs and guide ribs so that lift
support means
substantially separated in that manner remain connected by way of at least one
thin base
body web before they are mounted in the lift system. This facilitates handling
thereof and
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positionally correct arrangement on drive wheel and deflecting wheel.
Alternatively, it is
possible for mounting to permanently or detachably connect two or more lift
support
means with an assembly band before they are mounted in the lift system.
A drive wheel and/or a deflecting wheel of a lift system according to an
embodiment of the
present invention has or have for each drive or guide rib an associated groove
in such a
manner that when the lift support means is laid in place the flanks of the
drive or guide rib
contact corresponding counter-flanks of the associated groove. In this
connection the
grooves are preferably formed in correspondence with the ribs of the lift
support means: if
the guide rib or drive rib has a specific flank height, flank width and/or a
specific flank
angle, then advantageously the counter-flanks of the associated groove have
substantially
the same flank height and/or flank width and/or substantially the same flank
angle. In
particular it is preferred for the penetration depth by which at least one,
preferably each,
guide rib of a lift support means according to the present invention
penetrates into a
groove in a deflecting wheel to be greater than the penetration depth by which
the at least
one, preferably each, drive rib penetrates into a groove in a drive wheel. In
other words,
preferably at least one, preferably each, groove in a deflecting wheel is so
formed that the
projection of the contact surface between a flank of a guide rib arranged in
this groove and
the corresponding counter-flank of this groove is greater in axial and/or
radial direction
than the corresponding projection of the contact surface between a flank of at
least one,
preferably each, drive rib and the corresponding counter-flank of a groove,
which is
associated with this drive rib, in the drive wheel.
The drive wheel or the drive wheels can have several drive zones which are
looped
around at least partly by the or each lift support means. Advantageously, a
lift support
means loops around a drive wheel with an angle of wrap of 180 , preferably
less than
180 , preferably less than 1500, particularly preferably less than 1200 and
especially 90 .
Due to the small bending radii, which are possible, of the lift support means
it is possible to
connect the drive with a separate drive pulley or, however, to integrate drive
zones in a
drive output shaft with a drive. Drive pulleys and drive shafts provided with
drive zones
are therefore uniformly referred to as drive wheel. Advantageously, the
diameter of a drive
wheel is less than or equal to 220 millimetres, preferably less than 180
millimetres,
preferably less than 140 millimetres, preferably less than 100 millimetres,
preferably less
than 90 millimetres and preferably less than 80 millimetres. The tension
forces are
CA 02596726 2007-08-09
14
introduced into the belts by the drive wheel in friction-coupling and/or shape-
coupling
manner.
A lift support means can be constructed as an endless belt, the ends of which
are fastened
to beft locks. The belt can, particularly in the case of difficult deflecting
conditions, for
example be led through openings or placed on belt wheels mounted so as to be
non-
aligned.
Further objects, features and advantages are evident from the subclaims and
the
examples of embodiment described in the following. For this purpose, with
partly
schematic illustrations:
Fig. 1 shows a section through a lift system according to an embodiment of the
present
invention;
Fig. 2 shows a lift support means according to an embodiment of the present
invention for
explanation of mentioned specifications;
Fig. 3 shows a part section through a lift support means of the lift system of
Fig. 1, along
the line III-III;
Fig. 4 shows a part section through a lift support means of the lift system of
Fig. 1, along
the line IV-IV;
Fig. 5 shows a pre-product of the lift support means of Fig. 2;
Fig. 6 shows an embodiment of a combination of lift support means of Fig. 2,
produced
from the pre-product of Fig. 5; and
Fig. 7 shows a further embodiment of the combination of lift support means of
Fig. 2.
Fig. 1 shows a section through a lift installation, which is installed in a
lift shaft 12
according to an embodiment of the present invention. This comprises a drive,
which is
fixed in the lift shaft 12, with a drive wheel 20, a lift cage 10, which is
guided at cage guide
rails 11, with two deflecting wheels, which are mounted below the cage floor,
in the form of
CA 02596726 2007-08-09
cage support rollers 21.2, 21.3, a counterweight 13 with a further deflecting
wheel in the
form of a counterweight support roller 21.1 and several lift support means,
which are
constructed as wedge-ribbed belts 1, for the lift cage 10 and the
counterweight 13, which
transmit the drive force from the drive wheel 20 of the drive unit to the lift
cage and the
counterweight.
Each wedge-ribbed belt 1 is fastened at one of its ends below the drive wheel
20 at a first
belt fixing point 14.1. From this it extends downwardly to the counterweight
support roller
21.1, loops around this and extends out from this to the drive wheel 20, loops
around this
and runs downwardly along the cage wall of the counterweight side, loops on
either side of
the lift cage around cage support rollers 21.2 and 21.3 - which are
respectively mounted
below the lift cage 10 - each time through approximately 90 and run upwardly
along the
cage wall remote from the counterweight 13 to a second belt fixing point 14.2.
The plane of the drive wheel 20 can be arranged at right angles to the cage
wall at the
counterweight side and its vertical projection can lie outside the vertical
projection of the lift
cage 10. It is therefore preferred that the drive wheel has a small diameter
of less than or
equal to 220 millimetres, preferably less than 180 millimetres, preferably
less than 140
millimetres, preferably less than 100 millimetres, preferably less than 90
millimetres, and
preferably less than 80 millimetres, so that the spacing between the cage wall
at the
counterweight side and the wall of the lift shaft 12 opposite thereto can be
as small as
possible. Moreover, a small diameter of the drive wheel 20 enables use of a
gearless
drive motor with a relatively low drive torque as drive unit. The belt fixing
points 14 are
devices which are known to the expert and in which the wedge-ribbed belt 1 is
clamped
between a wedge and a housing.
Figures 3 and 4 show a section through a lift support means in the form of a
wedge-ribbed
belt 1 of Fig. 1 according to an embodiment of the present invention. This
comprises a
base body 2 in which a tensile carrier arrangement 5 of four tensile carriers
is arranged.
As indicated in the figures, each tensile carrier is constructed as a steel
wire cable which
comprises a double-ply core strand with a core wire with 0.19 millimetres
diameter, a wire
layer, which is wrapped therearound in S wrap, of six wires with 0.17
millimetres diameter
and a wire layer, which is wrapped therearound similarly in S wrap, of twelve
wires with
0.17 millimetres diameter, as well as eight single-ply outer strands with a
core wire with
0.17 millimetres diameter and a wire layer, which is wrapped therearound in Z
wrap, of six
CA 02596726 2007-08-09
16
wires with 0.155 millimetres diameter, which are wrapped in S wrap around the
core layer.
A drive side (at the bottom in Fig. 3) of the lift support means 1 is intended
for contact with
the drive wheel 20 and the counterweight support roller 21.1. It has for this
purpose two
drive ribs in the form of wedge ribs 3, which, as shown in Fig. 3, engage in
associated
grooves 20.1 of the drive wheel 20 and are laterally guided by these. The
pressing
pressure thereby advantageously increases and therewith the traction
capability of the
drive.
A deflecting side (at the top in Fig. 4) of the lift support means 1 is
intended for contact
with the cage support rollers 21.2, 21.3 and has for this purpose a guide rib
in the form of a
wedge rib 4 which, as shown in Fig. 4, engages in an associated groove 21.5 of
the
deflecting wheel 21.3 and is laterally guided by this.
The dimensional sizes of the lift support means 1 are schematically shown in
Fig. 2. In
that case the flank height h3 or h4 of a drive rib 3 or of the guide rib 4 is
the projection of
the rib onto the median plane of the lift support means 1, which is spanned by
the length
axis and height axis (vertical in Fig. 2). The overall height h1 of the lift
support means is
thus composed of the flank heights h3, h4 of the drive and guide ribs 3, 4 and
the height
h2 of the base body 2. Due to this large flank height t4, this total height h1
is greater than
the width w of the lift support means, which advantageously increases the
bending
stiffness thereof about its transverse axis and thus counteracts jamming in
grooves 20.1 or
21.5. In the example of embodiment the ratio w/h 1= 0.906.
The flank width t3 or t4 of a drive rib 3 or of the guide rib 4 corresponds
with the projection
of the rib on the base body 2 of the lift support means 1, i.e.
perpendicularly to the flank
height (horizontal in Fig. 2). The overall width is denoted by w. The width of
a rib resufts
from its two flank widths t as well as the width of a(flattened) tip. Thus,
the width of a
drive rib 3 is, for example, 2 x t3 + d3 (cf. Figures 2, 3).
The flank angle a4 of the guide rib 4 is the internal angle between the two
flanks of the
guide rib 4 and in the example of embodiment is 80 . The correspondingly
defined flank
angle 0 of the drive ribs 3 is, in the example of embodiment, 900.
As recognisable in Fig. 2, the flank height h4 of the one guide rib 4 is
greater than the flank
CA 02596726 2007-08-09
17
height h3 of the two drive ribs 3. The guide rib 4 can thereby, as comparison
of Figures 3
and 4 shows, penetrate deeper into an associated groove 21.5 in the deflecting
wheel 21.3
than is the case with the drive ribs 3 and the associated grooves 20.1 of the
drive wheel
20. The guide rib 4 therefore remains, in the case of radial lifting off
(downwardly in Fig. 4)
which can set in, for example, due to the intrinsic weight of the lift support
means 1 in the
case of support means slackness, longer in the groove 21.5 and automatically
centres the
lift support means 1, after tightening thereof, again on the deflecting wheel
21.3. On the
other hand, the maximum spacing of the tensile carriers 5 from the drive side
is smaller, so
that a more homogenous distribution of force in the drive ribs 3 occurs.
As similarly recognisable in Fig. 2 the flank width t4 of the guide rib 4 is
also greater than
the flank width t3 of the two drive ribs 3. If the lift support means on a
wheel 20, 21
migrates outwardly by its maximum flank width t then it is returned to its
position by the
inclined flanks. Due to the greater flank width t4 the lift support means 1 is
thus guided at
its deflecting side over a wider region in transverse direction. This allows,
in particular,
also a more pronounced diagonal tension, since even a lift support means
entering at
greater inclination is still 'captured', due to its greater flank width, by
the corresponding
groove 21.5 of the deflecting wheel.
This is particularly advantageous, since, due to mounting tolerances with the
deflecting
wheels 21.2, 21.3 as well as the small spacing thereof from one another, a
more
pronounced diagonal tension can occur, which opposes the improved guidance at
the
deflecting side. In addition, greater tolerances can be accepted between the
deflecting
wheel 21.3 and the belt fixing point 14.2, since the wider and higher guide
rib 4 allows a
greater diagonal tension.
Partial compensation can be provided between drive wheel 20 and deflecting
wheel 21.2
for such diagonal tension by deformation of the lift support means, so that
the shorter and
narrower drive ribs 3 run into the drive wheel 20 with smaller diagonal
tension.
A guide rib 4 which extends over substantially the entire width w of the lift
support means 1
and is thus approximately twice as wide as the two drive ribs 3 is associated
with the two
drive ribs 3. In order to further increase the depth of penetration the flank
angle a4 of the
guide rib 4 is formed, at a 80 , to be more acute than the flank angle a3 of
the drive ribs 3.
CA 02596726 2007-08-09
18
Overall, the guide rib 4 thus has a significantly larger flank area f4 =4(t42
+ h4Z) than the
drive ribs 3 at f3 =4(t3Z + h3 2), which significantly improves the guidance
at the deflecting
side. On the other hand, the tensile carriers 5 are arranged near the drive
side, wherein
due to the flatter flank angle 0 the spacing from the drive side varies only a
little. Since,
in addition, two tensile carriers 5 are associated with each drive rib 3,
friction forces can be
transferred from the drive wheel 20 substantially by way of each flank drive
of a drive rib 3
to an associated tensile carrier 5, which has the effect of a particularly
homogenous
distribution of force in the drive ribs.
As schematically indicated in Fig. 3, the flattened tip of the drive rib 3 has
a width d3,
which width d3 is the same width as or wider than the minimum spacing d20 of
the two
counter-flanks of the groove 20.1 in the drive wheel 20. The edges which are
formed in
these counter-flanks and at which the inclined counter-flanks go over into a
rectangular
groove in the groove base thereby do not contact the flanks of the drive ribs
3, so that this
is protected against a corresponding notch effect. The same applies to the
guide rib 4 and
to the groove 21.5 associated therewith as is recognisable in Fig. 4.
On the other hand, the counter-flanks of adjacent grooves 20.1 of the drive
wheel go over
into one another by a radius R20 which is greater than a radius R3 by which
mutually
facing flanks of the adjacent drive ribs 3 go over into one another. The
contact between
the flanks of the drive ribs 3 and the counter-flanks of the grooves 20.1 thus
takes place
smoothly and without large notch effects.
The drive side can have at least in the regions of its wedge ribs 3, which
come into friction
couple with the flanks of the drive wheel 20, a coating (not illustrated) with
a PA film.
Advantageously the entire drive side is coated in a continuous or
discontinuous process,
which simplifies manufacture. Alternatively to the coating, a vapour
deposition and/or
flocking can also be provided. The vapour deposition is, for example, a metal
vapour
deposition. The flocking is, for example, a flocking with short synthetic or
natural fibres.
This vapour deposition or flocking can also extend over the entire drive side
and be carried
out in a continuous or discontinuous process. In principle, in the case of
pairings of wedge
ribs and grooves in which only the flanks of the wedge ribs bear against the
grooves with
friction coupling it is possible to provide only these flanks of the wedge
ribs with a coating
or vapour deposition and/or flocking, so that those regions between the rib
flanks which
are not in contact with the drive wheel 20 are uncoated. In addition, the
possibility exists
CA 02596726 2007-08-09
19
of providing the rib 4 with a coating reducing the coefficient of friction
and/or noise.
As indicated in Figures 3, 4 by dashed lines, apart from the lift support
means one or
several further, preferably constructionally identical, lift support means are
arranged and
spaced from one another by a gap 23 which is sufficient to prevent mutual
contact of the
lift support means on the drive or deflecting wheels even when the lift
support means
deform. Through such a lift support means combination a desired width of
narrow
individual lift support means which are easy to handle can be mounted on site
in simple
and quick manner, which significantly simplifies production and stock-keeping,
transport
and mounting and demounting. Due to the construction with two drive ribs 3,
with which
four tensile carriers are associated, the total load-bearing force of the lift
support means
combination can be adapted in fine steps by addition of individual lift
support means.
Through the narrow individual lift support means it can be avoided that a lift
support means
combination with n lift support means has to be reinforced by a further wide
lift support
means (n + 1) by a correspondingly large load-bearing force step and thus
significantly
over-dimensioned when the load-bearing force, which is made available by n
lift support
means, is only slightly less than the required total load-bearing force.
For mounting such a lift support means combination the lift support means 1
can be made,
as shown in Figs. 5 and 6, from a pre-product 7. The pre-product 7 consists of
two or
more lift support means 1 with a one-piece base body 2. The pre-product 7 is
partly
divided between drive ribs 3 and/or guide ribs 4 so that lift support means
remain
connected by way of at least one thin base body web 17 before they are mounted
in the lift
system. According to the embodiment of Fig. 6, three lift support means 1 are
connected
together by way of two base body webs 17. The base body webs 17 can, as shown
in Fig.
6, be mounted on the deflecting side of the lift support means 1 so that the
drive side of
the individual lift support means I is freely accessible even in the
composite. In particular,
the individual lift support means 1 in the composite can lie by their drive
side in
corresponding grooves of the drive wheel 20. In that case the base body webs
17 can
also guarantee correct lateral spacing 23 of the lift support means 1 from one
another on
the drive wheel 20. For this purpose the lift support means 1 are connected,
at lateral
assembly spacings from one another, by way of the base body webs 17, which
spacings
substantially correspond with the lateral spacings 23 of the individual lift
support means 1
on the drive wheel 20. After mounting has taken place the base body webs 17
can be
torn, for example in that the base body webs 17 are slightly shorter than the
lateral
CA 02596726 2007-08-09
spacings 23 of the lift support means 1 on the drive wheel 20 and the base
body webs 17
tear in controlled manner under the stress which arises. It is obviously also
possible to
provide the base body webs 17 on the drive side of the lift support means 1.
Alternatively, for mounting such a lift support means composite it is also
possible, as
shown in Fig. 7, for several lift support means 1 to be connected together by
way of an
assembly band 30. The assembly band 30 surrounds the lift support means 1 at
least
partly. For example two, three, four, six or eight lift support means form a
composite which
is partly surrounded by assembly band 30 and which, rolled up as a loop, can
be
transported in simple manner and without problems into the lift shaft 12. The
assembly
band 30 is, for example, fixed reversibly or irreversibly by material locking
to the lift support
means 1. Advantageously, it is a thin plastics material band with an adhesive
layer at one
side. The plastics material band is connected with the lift support means 1 by
way of the
adhesive layer. In the case of reversible material locking the adhesive band
can be pulled
off the lift support means 1 and the detached lift support means thus
separated.
Advantageously, the assembly band 30 is mounted on the deflecting side of the
lift support
means so that the drive side of the individual lift support means 1 is freely
accessible even
in the composite. In particular, the individual lift support means 1 in the
combination can
lie by way of their drive side in corresponding grooves of the drive wheel 20.
In that case
the assembly band 30 can also guarantee the correct lateral spacing 23 of the
lift support
means from one another on the drive wheel 20. For this purpose, the lift
support means 1
are connected at lateral assembly spacings from one another with the assembly
band 30,
which spacings substantially correspond with the lateral spacings 23 of the
individual lift
support means 1 on the drive wheel 20. It is obviously also possible to mount
the
assembly band 30 on the drive side of the lift support means 1.
