Object of the Invention
[0001] A first aspect of the present invention relates to a rope for elevator apparatuses
and a second aspect relates to an elevator apparatus comprising said rope, said two
aspects having application in the field of lifting, and more specifically in the elevator
industry, allowing achieving a rope, the flexural rigidity of which is lowered, that
can be used with sheaves having a small diameter with a deterioration level of the
rope less than that of the currently existing ropes, which allows extending their
useful life.
Background of the Invention
[0002] In the field of lifting, either in the elevator sector or in sectors such as that
of cranes, the use of different types of ropes, equally used for different purposes,
is known.
[0003] Ropes are used in the lifting industry, among other applications, as suspension elements,
i.e., for supporting or hanging loads therefrom, it being frequent for this application
that the rope passes though one or several sheaves.
[0004] At least one of said sheaves is usually driven by means of an engine, therefore the
rope, in addition to fulfilling the suspension function or application, also fulfills
a function in the means for driving the elevator, acting as an element transmitting
the torque from the sheave in a traction force which is used for moving the loads
comprised in the lifting system.
[0005] Other types of applications which have ropes in lifting systems comprise their use
in safety systems, being used to join or link different components of said safety
systems, the passage of said ropes through sheaves being equally required in these
cases.
[0006] In any case, in all previously mentioned applications, during their passage though
a sheave the rope passes from a straight position to a curved position, returning
to the straight position when said rope leaves the sheave again, which causes the
rope to be subjected to bending stresses, in addition to the tensile stresses due
to the weight of the different loads.
[0007] It is also known in the lifting sector that throughout its useful life the rope repeatedly
passes a great number of times through the sheave, causing the previously mentioned
change between the straight configuration and the curved configuration, and vice versa,
whereby the internal stresses occurring in the rope and those occurring between the
rope and sheave give rise to mechanical fatigue and wear phenomena both outside and
inside the ropes, which over time cause a deterioration of the rope, requiring its
replacement.
[0008] In addition to affecting the safety of the lifting systems and means, all these phenomena
have to be taken into consideration when designing the elements and components of
an elevator, which implies an increase in the costs of said elevator, for which reason
the lifting industry has made several attempts to reduce the effect of these phenomena,
among which there is a trend to reduce the diameter of the sheaves and maintain a
safety ratio between the diameter of a sheave D and the diameter of a rope d, such
that said effects are reduced by means of fulfilling the following expression:
[0009] With regard to fatigue and wear effects, the use of lubricants is one factor which
reduces said effects, although said reduction involves a decrease of the traction
capacity of the rope-sheave system, which is counterproductive.
[0010] Ropes coated with polymer materials have been recently used, whereby the coefficient
of friction between the rope and the sheave is increased at the same time as the wear
effect is decreased. These coatings having implied a considerable improvement in the
useful life of these types of elements. For example, in European patents
EP 1273695,
EP 1517850 and
EP 1597183 coated ropes for their use in lifting systems are described.
[0011] In this sense, the recent use of flat ropes, also called belts, implies another significant
advancement in suspension and traction means for lifts. European patent
EP 1023236 and PCT patent applications
WO 99043885 and
WO 00037738 describe these types of ropes as suspension and traction systems which have a width
or length a significantly greater than their thickness or edge b.
[0012] The advantage which these flat ropes have is that for a single suspension and traction
capacity they have a flexural rigidity less than that of a conventional rope. This
is due to the fact that the traction capacity of these elements mainly depends on
the area of their cross-section A
t, which can be represented by means of the following expression:
[0013] Where a is the width of the rope and b is its thickness.
[0014] In addition the flexural rigidity of the rope depends on the moment of inertia I
x of the cross-section A
t with respect to an x-axis, coinciding with the neutral axis of said cross-section
A
t, i.e., in the situation in which the bending occurs as a result of the passage of
the rope through a sheave, the x-axis is an axis parallel to the rotating shaft of
said sheave, therefore the moment of inertia I
x is obtained with the following expression:
[0015] It turns out that if the area of a cross-section is kept constant, the following
expression is obtained:
[0016] If this formula is replaced in the formula for flexural rigidity, the following expression
is obtained:
[0017] This formula indicates that for a constant area, the flexural rigidity of a longitudinal
traction element of cross-section A
t decreases when its edge or thickness b decreases and therefore its width a increase.
[0018] A reasoning similar to that previously explained can be carried out without difficulty
for the stresses caused inside the rope as a result of the bending upon its passage
through the sheave, which are the stresses causing a good part of the deterioration
of the traction element, whereby it is concluded that the use of traction elements
with a flat shape or configuration is beneficial for achieving more economical, reliable
and safer lifting systems.
[0019] However, the use of belts in lifting systems can give rise to several problems and
drawbacks.
[0020] First of all, reducing the flexural rigidity of the rope causes vibrations to be
generated in the direction perpendicular to the smaller dimension of the belt, given
the that mechanical systems generally have more tendency to vibrate the more flexible
they are, unless elements are incorporated which provide damping, and tend to reduce
or absorb said vibrations over time.
[0021] It is also known that the greater the a/b ratio in a section is, i.e., the ratio
between the width a of the rope and its thickness b, the less the torsional rigidity
is compared with more compact sections, therefore the torsional vibration is also
higher in these sections.
[0022] Furthermore, in round sections the torsional vibrations can go unnoticed due to the
polar symmetry of the section. In this same sense, some geometric configurations of
lifting installations induce a rotational movement on their own shaft of the rope
as the loads move vertically. If the section of the rope is circular, the rope can
rotate in its contact with the sheave, which rotation allows it to adapt to the configuration
of the installation. In ropes with non-circular sections said rotation is not possible
and the rope or belt is confined by the sheave, causing additional stresses, generally
torsional stresses.
[0023] In addition, the use of irregular geometries, as reflected for example in
PCT patent application WO 2002064883, different from a circular configuration, gives rise to permanent deformations of
different types which do not occur in the case of circular sections, and even if they
do occur, they go completely unnoticed. The causes generating or causing said permanent
deformations are similar to those set forth for the case of vibrations. These permanent
deformations are often due to several reasons, such as manufacturing processes, storage
processes, assembly operations or the actual way of using the belts.
[0024] Currently belts or flat ropes with a configuration different from the circular configuration,
can only be supported on the channels of the sheave only on one of their two faces,
which further restricts the type of geometric configuration which can be adopted by
an installation using these types of traction and suspension means. With regard to
this requirement, which is inherent to the configuration of a belt, there is the drawback
that belts usually have constructive defects or manufacturing errors preventing their
correct use, such as not being flat or parallelism errors between the faces.
Description of the Invention
[0025] A first aspect of the present invention relates to a rope for elevator apparatuses
the flexural rigidity of which is less than that of the currently existing ropes,
allowing its use with sheaves having a reduced diameter, which achieves maintaining
a deterioration level less than that of said conventional ropes during an extended
useful life, with the subsequent increase in safety and savings in the costs of maintaining
the elevator apparatus.
[0026] The rope for elevator apparatuses proposed by the invention comprises at least two
linear resistant elements parallel to one another along the entire length of the rope.
[0027] Said resistant elements provide rigidity to the rope and are located close to a central
axis of a cross-section A
t of the rope. Each resistant element has a cross-section a
t, such that the cross-sections a
t of the resistant elements are aligned parallel to the central axis of the rope.
[0028] The cross-section A
t of the rope of the invention has a width a and a thickness b, the ratio between said
width a and said thickness b being substantially equal to one along the entire rope.
[0029] Magnitude or width a of the section of the rope is understood in the description
as the measurement of the rope at an axis passing through the geometric centers of
the resistant elements inserted in the rope, whereas the magnitude or thickness b
of the section of the rope is understood in the description as the measurement of
the rope at an axis perpendicular to the axis traversing the geometric centers of
the resistant elements inserted in the rope, and which in turn passes through the
geometric center of the section of the rope.
[0030] In the present description of the invention it is understood that the term substantially
relates to the ratio between the width a divided by the thickness b of the rope which
is not less than 0.8 or greater than 1.2, therefore it is obvious that with these
dimensional ranges small variations are included in said aspect ratio due to the fact
for example that the rope is in a load and/or curved position due to the effect of
its passage through a sheave.
[0031] According to a preferred embodiment of the invention, it is provided that the rope
comprises at least one alignment of cross-sections a
t of elements aligned on the central axis of the cross-section A
t of the rope.
[0032] Likewise, it is also provided that the rope comprises at least two alignments of
cross-sections a
t of resistant elements aligned close to the central axis of the cross-section A
t of the rope.
[0033] The resistant elements provide most of the rigidity to the rope and are located in
the cross-section of the rope in positions close to the central axis, preferably coinciding
with a neutral horizontal plane of bending of the rope when said rope is subjected
to bending as a consequence of its passage through a sheave.
[0034] In the case in which the resistant elements of the rope, as well as its cross-section
A
t, have a symmetrical arrangement, the neutral horizontal plane of bending of the rope
will coincide with the horizontal geometrical plane of symmetry thereof.
[0035] When the rope object of the invention undergoes bending stresses due to its passage
through a sheave or through any other means, and due to the fact that its rigidity
is much lower in the plane defined by the resistant elements, the rope will bend taking
the central axis around which said resistant elements are distributed as a neutral
axis, whereby the axial deformation, i.e., the compression and/or tensile stresses
to which the resistant elements are subjected will be minimal, therefore the bending
stresses in the rope are reduced to a great extent.
[0036] In the event that the resistant elements are formed by a plurality of intertwined
wires, the relative movement between said wires, an effect causing internal abrasion
phenomena, is equally reduced.
[0037] Therefore, due to the fact that these two factors are those generating fatigue and
wear, the degradation of the rope of the invention is greatly reduced, which allows
extending the useful life of the rope, maintaining the required safety levels during
such useful life.
[0038] The possibility is also provided that the rope of the invention comprises at least
one linear damping element, having a cross-section a'
t which is located in an area of the cross-section A
t of the rope which is away from the central axis of said cross-section A
t of the rope, having a function and purpose different from that of the resistant elements
consisting of damping the damaging vibrations occurring in the thin configuration
of said resistant elements, as previously explained.
[0039] It is likewise provided that the rope comprises at least two damping elements located
on both sides of the central axis of the cross-section A
t of the rope, whereby it would have a symmetrical rope configuration with respect
to the central axis.
[0040] As in the case of the arrangement of the resistant elements, the possibility is provided
that the rope comprises a plurality of damping elements the cross-sections a'
t of which are aligned parallel to the central axis of the cross-section A
t of the rope, therefore being arranged parallel to the cross-sections a
t of the resistant elements, all of them being parallel to a rotating shaft of a sheave
through which the rope passes.
[0041] This set of damping elements, which also occupy the entire length of the rope, but
which are located or distributed in areas of the section away from the central axis,
is preferably constructed with geometric configurations and/or materials providing
little rigidity but having a high internal dissipation or damping capacity due to
friction.
[0042] The damping elements can be formed using polymer materials, or any other material
having a high internal damping coefficient. It is provided that the damping elements
are made with twisted wires, such that the energy is dissipated due to rubbing the
wires with each other.
[0043] Given their arrangement, the damping elements are located in areas away from the
neutral horizontal plane of bending of the rope, i.e., the central axis.
[0044] When the rope is subjected to bending due to its passage through a sheave, the axial
deformation occurring in the damping elements is much higher than the case of the
resistant elements due to the fact that they are further from the central axis, i.e.,
from the neutral axis of the cross-section A
t of the rope, whereby the energy dissipated by said damping elements is greater, such
that the vibrations caused by the dynamics of the installation are damped in less
time, i.e., quicker.
[0045] It is provided as a possibility that the rope of the invention comprises a sheath
containing the resistant elements, said sheath being made of a material having a high
coefficient of friction, said sheath being configured to be in contact with at least
one sheave, a traction or deviation sheave. It is provided that the resistant elements
are completely or partially embedded in said sheath, being able to even penetrate
between said resistant elements, or they are simply contained or encapsulated therein.
[0046] It is likewise provided that the rope comprises a sheath containing the resistant
elements and said at least one damping element, the sheath being made of a material
having a high coefficient of friction, and being configured to be in contact with
at least one sheave.
[0047] As in the case of the resistant elements, the sheath can contain or encapsulate the
resistant elements and the damping elements, or penetrate between said damping and
resistant elements, in which they would be completely or partially embedded.
[0048] The sheath, or coating, can be made with a polymer material, or any other material
with a low rigidity level and a high coefficient of friction with the sheave, in addition
to a high level of adherence with respect to the resistant elements and to the damping
elements.
[0049] It is provided that the sheath is made with polymer materials similar to those used
in belts or ropes which are currently used in lifting installations. This sheath has
a dual function, first of all it is useful for joining all elements comprised by the
rope, and secondly it is useful for ensuring a good grip between the rope and a sheave.
The use of this type of coating with a high coefficient of friction ensures that the
rope is not going to slide through the sheave. This allows using the sheave with non-aggressive
grooves, such as grooves with a U-shaped section, such that the damage produced in
the rope by contact with the sheave is considerably reduced.
[0050] The materials which are considered for making the sheath are natural polymers, such
as rubber or resins, synthetic polymers, such as nylon, as well as elastomers, plastics
or fibers, i.e., all types of either thermoplastic or thermosetting polymers.
[0051] According to a preferred embodiment, the sheath is made of polyurethane, this material
being the most used as a coating, being able to incorporate additive elements and/or
agents for the purpose of providing it with certain properties, such as for example
a fire-resistant or fire-retarding character.
[0052] It is likewise provided that the damping elements are made of the same material as
the sheath, i.e., the sheath is made of the actual material of the damping elements.
[0053] In addition to covering all the elements comprised in the rope, the sheath is useful
for keeping them in their relative position in the section of the rope. Furthermore,
the sheath provides adherence so that all elements of the rope move in an integral
manner both longitudinal and transversally. Finally, this sheath acts as an interface
between the elements of the rope and the sheave, providing adherence between the rope
object of the invention and the sheave and homogenizing the contact stresses which
could occur between said rope and said sheave.
[0054] The cross-sections a
t of the resistant elements are preferably operatively spaced from one another in the
cross-section A
t of the rope, i.e., having a relative distance between the centers of contiguous elements
which is comprised between 1.75 mm and 8 mm, although it can be outside said range,
being related to the transverse dimensions or the diameter of said resistant elements.
[0055] By way of an example, for a rope comprising three resistant elements, the diameters
of each of the resistant elements being 2 mm, a minimum breaking load (MBL) value
of approximately 12000 N is obtained. In the event that the resistant elements have
a diameter of 2.5 mm, a minimum breaking load (MBL) value of approximately 19000 N
is obtained. For resistant elements having a diameter of 3 mm, a minimum breaking
load (MBL) value of approximately 27000 N is obtained.
[0056] The possibility is provided that the cross-section A
t has any configuration, provided that it keeps the previously defined ratio between
the width a and the thickness b, being able to be circular, in which case the outer
geometry of the rope will be circular, or the cross-section A
t of the rope is not circular.
[0057] In the event that the cross-section A
t of the rope is not circular, said cross-section A
t is configured to be housed in a groove of a sheave, the cross-section A
t having a shape complementary to that of said groove, the central axis being in a
position parallel to a rotating shaft of the sheave, i.e., parallel to a neutral bending
axis of the cross-section A
t of the rope and parallel to the direction of the width a of the rope.
[0058] With regard to the geometry of the rope, it is necessary to consider that since there
is a great different between the bending moments of inertia of each axis of the cross-section
A
t of the rope, this causes the rope to always bend along one plane, and this effect
always determines the position of the rope upon its passage through a sheave.
[0059] As has been previously mentioned, the possibility of using ropes with a cross-section
different from the circular one, is subject to the fact that the width a of the cross-section
A
t of the rope is similar or of the same order of magnitude as the edge or thickness
b and to the fact that the resistant elements are located around the entire central
axis or neutral axis, and in the event of comprising damping elements, these are placed
in areas away from said central axis. The main reasons for using these alternative
sections are improving the uniformity of the thickness of the layer which is around
the damping and resistant elements, which allows working with grooves different from
semicircular grooves, adapting to different configurations of sheaves and grooves.
The use of grooves different from semicircular grooves further ensures that the rope
will not torsionally rotate upon its passage through said grooves. Furthermore, the
use of non-circular ropes allows an operator to visually check during the installation
of the rope that the rope is not twisted at any of the pulling sections between sheaves.
[0060] According to a preferred embodiment, the resistant elements comprise steel wires
preferably having a strength of not less than 2000 N/mm
2 and a diameter of less than 0.5 mm. Said steel wires can be twisted, forming strands,
the resistant elements can likewise comprise twisted ropes with strands.
[0061] In addition, it is provided that the resistant elements comprise wires made of synthetic
material, which can be equally twisted, forming strands, providing the possibility
that the resistant elements comprise twisted ropes with strands of wires made of synthetic
material, which can consist of aramid fibers, preferably Kevlar.
[0062] With regard to the damping elements, it is provided that they are made of polymer
material, both natural and synthetic, being able to be any plastic material, elastomer,
rubber, neoprene or resin, provided that it fulfills the condition of damping and
resisting compression without undergoing excessive deformation.
[0063] The possibility is provided that the rope comprises a visual mark configured to allow
identifying the position of the central axis of the cross-section A
t of the rope at any time from outside, for the purpose of allowing identifying the
arrangement of the resistant elements and the damping elements during the operations
for assembling the rope for a correct positioning thereof in a sheave.
[0064] A visual check that the rope is not twisted in any of the sections for pulling between
sheaves is thus allowed. Said visual mark can consist of a longitudinal mark in an
outer visible part of the rope, so that the person assembling it, ensures that the
rope is not twisted after the assembly process. The visual mark is equally useful
for checking that it has been correctly assembled and the rope is supported in the
groove of the sheave in the correct position.
[0065] A second aspect of the invention relates to an elevator apparatus comprising at least
one rope such as any of those previously described, such that said rope is in contact
with a traction sheave, the central axis of the rope being located in a position parallel
to the direction of the width a of the rope and parallel to a rotating shaft of said
sheave 5, i.e., parallel to a neutral bending axis of the cross-section A
t of the rope when said rope is in contact with a sheave.
[0066] The possibility is provided that the traction sheave of the elevator apparatus of
the invention has a pitch diameter of less than 160 mm.
[0067] In the case of a gear, pitch diameter is understood to be the diameter of a circumference
which would define a surface on which said gear would run without sliding. In the
case of the sheave of the elevator apparatus of the invention, pitch diameter is understood
to be the distance between the groove centers of the sheave, passing of course through
the center of said sheave.
[0068] The possibility is likewise provided that the pitch diameter of the traction sheave
is less than 40 times the diameter of a circle completely circumscribing the resistant
elements of the rope.
[0069] Obviously the rope comprised in the elevator apparatus of the invention, which the
first aspect of the invention relates to, can be a suspension and traction rope or
a speed governing rope of the lifting system.
Description of the Drawings
[0070] To complement the description being made and for the purpose of aiding to better
understand the features of the invention according to a preferred practical embodiment
thereof, a set of drawings is attached as an integral part of said description, in
which the following has been shown with an illustrative and non-limiting character:
Figure 1 shows a cross-section of an embodiment with a circular section of the rope
of the invention, in which the rope has three resistant elements located on the central
axis and two damping elements located at points away from said central axis.
Figure 2 shows a cross-section of a variant of the embodiment of the rope of the invention
comprising a plurality of alignments both of resistant elements, located near the
central axis, and dampers, away from said central axis.
Figure 3 shows a cross-section of another variant of the embodiment with a rhomboid
section of the rope proposed by the invention.
Figure 4 shows a cross-section of another variant of the embodiment of the rope of
the invention in this case with a cross-shaped section, in which it can be seen how
the thickness of an outer layer of the sheath is more constant than in the variants
shown in the previous figures.
Preferred Embodiment of the Invention
[0071] In view of the indicated figures it can be observed how in one of the possible embodiments
of the invention, a first aspect thereof relates to a rope for elevator apparatuses
comprising at least two linear resistant metal elements (1) parallel to one another
along the entire length of the rope.
[0072] According to a preferred embodiment of the invention, shown in Figure 1, the rope
comprises three resistant elements (1) located on a central axis (4) of a circular
cross-section A
t of the rope.
[0073] The resistant elements (1) are formed by a plurality of intertwined steel wires having
a strength of not less than 2000 N/mm
2 and a diameter of less than 0.5 mm.
[0074] Each resistant element (1) has a cross-section a
t, such that the cross-sections a
t of the resistant elements (1) are aligned on said central axis (4) of the rope.
[0075] The cross-section A
t of the rope of the invention has a width a and a thickness b, the ratio between said
width a and said thickness b being substantially equal to one, along the entire rope.
[0076] Magnitude or width a of the section of the rope is understood in the description
as the measurement of the rope at an axis passing through the geometric centers of
the resistant elements inserted in the rope, whereas the magnitude or thickness b
of the section of the rope is understood in the description as the measurement of
the rope at an axis perpendicular to the axis traversing the geometric centers of
the resistant elements inserted in the rope, and which in turn passes through the
geometric center of the section of the rope.
[0077] The figures attached to the following description specify which is the magnitude
a and the magnitude b of each of the ropes which will be referenced in the mentioned
invention.
[0078] According to the preferred embodiment shown in Figure 1, the rope comprises two linear
damping elements (2) made of polymer material, symmetrically arranged one on each
side of the central axis (4), each of which has a cross-section a'
t which is located in an area of the cross-section A
t of the rope which is away from the central axis (4) of said cross-section A
t of the rope.
[0079] The rope comprises a sheath (3) made of polyurethane completely embedding the resistant
elements (1) and the damping elements (2), said sheath (3) being configured to be
in contact with a traction sheave (5).
[0080] The cross-sections (a
t) of the resistant elements (1) are operatively spaced from one another in the cross-section
(A
t) of the rope.
[0081] The rope likewise comprises a visual mark, not depicted, which is configured in order
to allow identifying the position of the central axis (4) of the cross-section A
t of the rope at any time from outside for the purpose of allowing identifying the
arrangement of the resistant elements (1) and the damping elements (2) during the
operations for assembling the rope for a correct positioning thereof in a traction
sheave (5).
[0082] According to the variant of the embodiment shown in Figure 2, the rope has a circular
cross-section A
t and comprises an alignment of cross-sections a
t of resistant elements (1) aligned on the central axis (4) and two other alignments
of cross-sections a
t of resistant elements (1) aligned close to said central axis (4) of the cross-section
A
t of the rope.
[0083] The rope comprises a plurality of damping elements (2) the cross-sections a'
t of which are aligned parallel to the central axis (4) of the cross-section A
t of the rope, therefore being arranged parallel to the cross-sections a
t of the resistant elements (1).
[0084] In addition, according to the variants of the preferred embodiment shown in Figures
3 and 4, the cross-section A
t of the rope has non-circular configurations, being rhomboid and cross-shaped respectively
in the depicted sheaths.
[0085] In these cases the cross-section A
t is configured to be housed in a groove (6) of the sheave (5), the cross-section A
t having a shape complementary to that of said groove (6), the central axis (4) being
in a position parallel to a rotating shaft of the sheave (5), i.e., parallel to a
neutral bending axis of the cross-section A
t of the rope and parallel to the direction of the width a of the rope.
[0086] A second aspect of the invention relates to an elevator apparatus comprising a rope
such as any of those previously described, such that said rope is in contact with
a traction sheave (5), the central axis (4) of the rope being located in a position
parallel to the direction of the width (a) of the rope and parallel to a rotating
shaft of said sheave (5).
[0087] The traction sheave (5) of the elevator apparatus of the invention has a pitch diameter
less than 40 times the diameter of a circle completely circumscribing the resistant
elements (1) of the rope.
[0088] In view of this description and set of figures, a person skilled in the art could
understand that the embodiments of the invention which has been described can be combined
in multiple ways within the object of the invention. The invention has been described
according to several preferred embodiments thereof, but for a person skilled in the
art it will be obvious that multiple variations can be introduced in said preferred
embodiments without departing from the object of the claimed invention.
1. Rope for elevator apparatuses, characterized in that it comprises at least two linear resistant elements (1) parallel along the entire
length of the rope and located close to a central axis (4) with a cross-section At of the rope, said resistant elements (1) having cross-sections at which are aligned parallel to said central axis (4), said cross-section At having a width a and a thickness b, the ratio between said width a and said thickness
b being substantially equal to one.
2. Rope for elevator apparatuses according to claim 1, characterized in that it comprises at least one alignment of cross-sections at of resistant elements (1) aligned on the central axis (4) of the cross-section At of the rope.
3. Rope for elevator apparatuses according to any of the previous claims, characterized in that it comprises at least one linear damping element (2) having a cross-section a't which is located in an area of the cross-section At of the rope which is away from the central axis (4) of said cross-section At of the rope.
4. Rope for elevator apparatuses according to claim 3, characterized in that it comprises at least two damping elements (2) located on both sides of the central
axis (4) of the cross-section At of the rope.
5. Rope for elevator apparatuses according to any of the previous claims, characterized in that it comprises a sheath (3) containing the resistant elements (1), said sheath (3)
being made of a material which has a high coefficient of friction, said sheath (3)
being configured to be in contact with at least one sheave (5).
6. Rope for elevator apparatuses according to any of claims 3 and 4, characterized in that it comprises a sheath (3) containing the resistant elements (1) and said at least
one damping element (2), said sheath (3) being made of a material having a high coefficient
of friction, said sheath (3) being configured to be in contact with at least one sheave
(5).
7. Rope for elevator apparatuses according to any of the previous claims, characterized in that the cross-sections at of the resistant elements (1) are operatively spaced from one another in the cross-section
At of the rope or in contact.
8. Rope for elevator apparatuses according to any of the previous claims, characterized in that the cross-section At of the rope is circular.
9. Rope for elevator apparatuses according to any of claims 1 to 7, characterized in that the cross-section At of the rope is not circular, said cross-section At being configured to be housed in a groove (6) of a sheave (5), the cross-section
At having a shape complementary to that of said groove (6), the central axis (4) being
in a position parallel to a rotating shaft of the sheave (5).
10. Rope for elevator apparatuses according to any of the previous claims, characterized in that the resistant elements (1) comprise steel wires having a strength of not less than
2000 N/mm2 and a diameter of less than 0.5 mm.
11. Rope for elevator apparatuses according to any of the previous claims, characterized in that the resistant elements (1) comprise wires made of synthetic material.
12. Rope for elevator apparatuses according to any of claims 5 to 11, characterized in that the sheath (3) is made of polymer material.
13. Rope for elevator apparatuses according to any of the previous claims, characterized in that it comprises a visual mark configured to allow identifying the position of the central
axis (4) of the cross-section At of the rope.
14. Elevator apparatus, characterized in that it comprises at least one rope according to any of the previous claims which is in
contact with a traction sheave (5), the central axis (4) being located in a position
parallel to a rotating shaft of said traction sheave (5).
15. Elevator apparatus according to claim 14, characterized in that the traction sheave (5) has a pitch diameter of less than 160 mm.
16. Elevator apparatus according to claim 15, characterized in that the pitch diameter of the traction sheave (5) is less than 40 times the diameter
of a circle completely circumscribing the resistant elements (1) of the rope.