Note: Descriptions are shown in the official language in which they were submitted.
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Descriptive Report of the Invention Patent for a "A RAILROAD
SLEEPER"
Field of the Invention
[001] The present invention relates to a railroad sleeper and to a process for
manufacturing a railroad sleeper. More specifically, the present invention
relates to a railroad sleeper provided with a hollow sector and to the process
of making it.
Description of the prior art
[002] Railroad sleepers represent one of the various components of a railroad
network and, in conjunction with the ballast and other fixing elements,
promote
correct anchorage (fixation) of the rails on which the coaches travel.
[003] The great majority of the elements disclosed in the prior art is made of
wood (about 90%), the rest being steel, concrete or recycled-plastic sleepers.
[004] A wooden sleeper has useful life estimated in a few decades, so that,
after this period, it is necessary to replace it. The estimate that over 3
million
wooden sleepers are replaced each year, coupled with the legal restrictions
relating to the use of determined types of this raw material causes the
sector to look for alternatives to the element in question.
[005] An alternative concentrated on the use of sleepers made of wood, steel,
concrete, reforestation-wood, plastic (be it recycled or virgin).
[006] The use of sleepers made of virgin plastic exhibited good behavior. On
the other hand, the use of this type of sleeper is restricted to passenger-
transportation railroads, of narrow gage, subject to efforts other than those
resulting from a load system.As to the recycled plastic sleepers, these
were used in a few railroad networks and represented serious
structural problems, with endem ic dissemination of cracks, warping and
fixation problems.
[007] Basically, with a recycled sleeper it becomes difficult to obtain
homogeneity in the material constituting the sleeper. Thus, due to the
structural problems detected and the accidents (derailment) generated, the
use of this type of sleeper becomes virtually impossible.
[008] Concrete sleepers, in spite of being widespread in railroad networks
around the world, have not proved to be suitable for the characteristics of
the
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railroad beds and ballasts of the lines existing in some countries (such as
Brazil), due to the great inertia and rigidity of the commercial models that
are
most commonly available.
[009] This fact tends to cause high break of ballast and, as a result,
increase
the railroad-maintenance costs, besides enabling the occurrence of accidents.
[0010] Classified according to their shape, concrete sleepers may be
of the singleblock type, formed by a single rigid and continuous piece, are
subjected to great bending moments, which appear at different sections of the
sleeper.
[0011] There are also concrete sleepers of the twin-block type (mixed
sleepers), composed by two rigid blocks of reinforced concrete arranged under
each rail and joined by a flexible steel bar.
[0012] Thanks to the elasticity of the beam, the two blocks of concrete
will be immune to most stresses of static bending and alternating bending,
which sleepers made of pre-stressed concrete hardly resist.
[0013] Among concrete sleepers, there are also poly-block sleepers, wherein
two reinforced-concrete blocks are arranged at the ends in
conjunction of an intermediate piece, also made from concrete. The
blocks of the sides, as well as the intermediate one, are joined by steel
means
of rods having high elastic limit, stressed and anchored at the ends.
[0014]A few advantages with regard to the use of concrete sleepers over
wooden sleepers can be cited: for example, concrete sleepers have durability
of about 50 years, exhibit lateral and vertical rigidity by virtue of their
larger
mass and elastic fixation.
[0015] Further, concrete sleepers enable easy and rapid replacement of the
rails, as well as an increase in the useful life thereof and reduction in the
bending stresses (on the rail), by virtue of the stability of the railroad.
[0016] Additionally, with concrete sleepers, the frequency of derailments
is reduced and, as a result, there is an improvement in the trip quality
and a significant reduction in the cost of permanent maintenance.
[0017] On the other hand, the use of concrete sleepers presents a few
disadvantages, such as higher transportation cost, due to the greater weight
of
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this sleeper as compared with the wood ones, as well as the questionable
re-use of the sleeper after the occurrence of derailment.
[0018] Additionally, using concrete sleepers, the fixation systems are
not adjustable to the rail wear and to the widening of the railroad. Further,
there
is the need for expensive equipment for installing and maintaining the
railroads
and, in some situations, damage may by caused to the ballast due to the great
weight of the sleeper.
[0019] As already mentioned, in addition to concrete and plastic sleepers, the
prior art further discloses sleepers made of steel. Steel sleepers exhibit
satisfactory behavior when in use. On the other hand, they may have high and
uncertain costs, since their weight depends directly on the price of the
steel,
which is extremely instable.
[0020] The fixation of this type of sleeper is usually made by means of screws
and chestnuts and need permanent maintenance. Further, the fixation by
means of screw ends up weakening the sleeper due to the bores made therein.
[0021] As advantages of this type of sleeper, one can cite the possibility
of recycling, long useful life (about 60 years), is inert and non-toxic,
exhibits
low installation cost, its transportation is simple and it non-combustible by
virtue
of its manufacture material.
[0022] As
disadvantages, the use of steel sleepers requires a
greater number of interventions and change in the tamping area.
Further, this type of sleeper may entail the interruption of the trip, due
to the isolation jeopardy and still may undergo corrosion problems.
[0023] With regard to wooden sleepers, these should be previously) treated
(chemically), in order to be suitable for use. Obviously, such a chemical
treatment is harmful to the environment.
[0024] Said chemical treatment stations are responsible for storing the
sleepers and for applying preservatives, with a view to prolong the useful
life
of the sleeper and preventing the proliferation of fungi and insects.
[0025] Besides being a long process, comprising a number of steps, the
process of treating sleepers may cause various environmental
problems, such as air pollution, due to the breaking of storage tanks,
treatment cylinders and tubing that contain the preserving agents.
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[0026] Additionally, the absorption, inhalation and ingestion of chemical
products on the part of employees is not rare. Also the use of herbicides and
pesticides may contaminate the soil and the streams, causing changes in the
behavior of the fauna and the possibility of extinction of species.
[0027] It is further possible to use sleepers made from reforestation wood,
this
type of sleeper exhibiting resistance significantly lower than that of hard
wood.
[0028] Additionally, the impossibility of treating sleepers with some products
(such as creosote) that are strongly aggressive to the environment enables the
sleeper to be attached by biological agents, such as bacteria and white ants,
resulting in an extremely short life time (on the order of three to four
years),
which is much shorter than the useful life of sleepers made from hard wood.
[0029] The present invention aims at overcoming the problems existing in the
use of the above-mentioned sleepers by means of the structural configuration
and process of manufacturing a railroad sleeper.
[0030] The proposed sleeper does not have restrictions as to its use,
being suitable for use on railroad lines in both construction and
operation, for transporting loads and/or passengers.
[0031] Plastic sleepers (either virgin or recycled) known from the prior art
do
not exhibit optimized combination between weight of the piece and elasticity
module.
[0032] Most known plastic proposals imitate exactly the shape of an wooden
sleeper, making the piece heavier and consuming not only more raw material,
but also man-hour and hour-machine for making the pieces. Such factors make
the production process slow and increase the final price of the sleepers.
[0033] The present invention proposes a railroad sleeper, preferably but
not exclusively made of polypropylene with fiberglass, manufactured from a
highproductivity process, preferably extrusion, further having a structural
shape that
enables one to achieve and rigidity dose to those of the hard-wood sleepers,
aswell as competitive costs.
[0034] Additionally, the sleeper proposed in the present invention has a
reduced final price, which facilitates transportation and installation of the
piece,
enabling the use of standard fixing devices used on wooden sleepers, uses
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standard machines employed for installation and maintenance of sleepers and,
due to its manufacture material, enables one to recycle the product at the end
of the useful life of the sleeper.
[0035] Structurally, the proposed railroad sleeper comprises a hollow sector
5 (bored-through sector), which acts as an important differential for the
function
and characteristic of anchoring on the ballast. Due to its proposed shape, the
ballast used on the railroad will penetrate the sleeper, thus becoming an
integral body.
[0036] With the compaction of the ballast inside the sleeper, greater rigidity
for
the ballast/sleeper system will be generated and the final inertia moment will
be the sum of the inertia moment of the sleeper and the ballast layer arranged
inside it.
[0037] Additionally, due to the proposed shape of the railroad sleeper,
one has a light sleeper (ranging from 40 to 45kg), easy to install and
maintain,
easy to be carried by two workers, and suitable for being transported by
engaging one piece to another (one sleeper to another), thus brining
numberless
logistic advantages.
Objectives of the invention
[0038] The present invention has the objective of developing a high-
performance railroad sleeper for use in railroad lines under construction or
operation, used for transporting loads and/or passengers.
[0039] An additional objective of the present invention is to provide a
railroad
sleeper whose installation and production processes are simplified,
reducing working times, meeting the demand of the Market and guaranteeing
efficiency in the cycle of use of the piece.
[0040] The present invention has also the objective of overcoming (in the
most part) the main problems of present solutions (described in the prior
art),
such as high rigidity and weight of the concrete, which damage the ballast
layers, short useful life of the poor-quality wood, and the electric
conductivity
of the steel, as well as the problem of reliability of the solutions that use
recycled resins.
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[0041] Further, the present invention has the objective of providing a
railroad sleeper of sustainable appeal, which preferably uses polypropylene
as a raw material and can be recycled at the end of its useful life.
[0042] The present invention has the additional objective of providing a
railroad
sleeper provided with a hollow sector, thus enabling the ballast of the
railroad
network to penetrate into the sleeper and potentiate the rigidity of
the ballast/sleeper system.
[0043] It is also one of the objectives of the present invention to provide a
structural configuration of a railroad sleeper provided with an inverted-U
shape.
[0044] An additional objective of the present invention is to provide a
railroad sleeper made from a first material and from a composition comprising
said first material.
[0045] A further objective of the present invention is to provide a railroad
sleeper, the inner and outer walls of which are made from a first material,
and
the layer arranged between such walls is made from a composition comprising
the first material. The inner wall (or inner layer) may optionally not be
included.
[0046] Similarly, the outer wall (or outer layer) may optionally not be
present.
[0047] Thus, it is anticipated that embodiments including an inner wall and an
intermediate layer (as further described below), an outer wall and an
intermediate layer, and an intermediate layer without inner and outer walls
would be effective for purposes of the present invention.
[0048] The present invention has also the objective of providing a railroad
sleeper made by an extrusion/co-extrusion process.
[0049] An additional objective of the present invention is to provide a
railroad
sleeper whose hollow sector comprises a support groove.
[0050] An additional objective of the present invention is to provide a
process
for manufacturing a railroad sleeper by an extrusion process that enables
compaction of the composition used in making the sleeper within the calibrator
of the extruding machine, as well as homogeneous cooling of the whole
thickness of the sleeper that is being produced.
[0051] Finally, the present invention has the objective of meeting, on a large
scale, the Brazilian Market with good quality and reliability.
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Brief description of the invention
[0052] The objectives of the present invention are achieved by means
of a high performance railroad sleeper, produced preferably from
polypropylene with high fiberglass contents, which may range from 5 to 40%,
manufactured preferably by an extrusion process with a layer of pure
polypropylene as an envelope applied by the co-extrusion process.
[0053]The proposed railroad sleeper exhibits high elastic
module and performance dose to that of wood, thus enabling application
on railroads for transporting load and passengers. The railroad sleeper
proposed in the present invention has the following main advantages:
= availability and reliability of the raw material to meet the Market on a
large
scale;
= good electric insulator;
= high elastic module;
= totally recyclable;
= installation and maintenance equal to those of wooden sleepers,
employing the same tools and equipment;
= greater ease of transportation and maintenance, reducing logistic costs;
= it is inert and impermeable,
= it can be used in conjunction with the wooden sleeper;
= it enables the use of the fixation systems employed at present on
wooden sleepers;
= it enables the production of different lengths and shapes of sleeper to
meet
different gages and AMV's (line shift apparatus);
Brief description of the drawings
[0054] The present invention will now be described in greater detail with
reference to an example of embodiment represented in the drawings. The
figures show:
Figure 1 is a top representation of a railroad network suitable for
receiving the railroad sleeper proposed in the present invention, wherein
figure 1(a) represents a simple railroad network and figure 1(b) represents a
railroad network of multiple rails;
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Figure 2 is a representation of the cross section of an embodiment
proposed for the railroad sleeper;
Figure 3 is an additional representation of the cross section of
an embodiment proposed for the railroad sleeper, showing its preferred
dimensions,
Figure 4 is a representation of the cross section of an
additional embodiment proposed for the railroad sleeper;
Figure 5 is a representation of the cross section of an additional
embodiment proposed for the railroad sleeper;
Figure 6 is a representation of the cross section of the
structural embodiment proposed for the railroad sleeper shown in figure 5,
illustrating its preferred configurations;
Figure 7 is a representation of the cross section of an
additional embodiment of the railroad sleeper proposed in the present
invention;
Figure 8 is an additional representation of the cross section of the
railroad sleeper shown in figure 7, illustrating its preferred;
Figure 9 is a representation of an additional embodiment
proposed for the railroad sleeper proposed in the present invention, this
embodiment comprising a support groove;
Figure 10 is a representation of an additional embodiment proposed for
the railroad sleeper proposed in the present invention, this embodiment
comprising a plurality of support grooves;
Figure 11 is a representation of an additional embodiment proposed for
the railroad sleeper proposed in the present invention, this embodiment
comprising a plurality of Anchorage teeth;
Figure 12 is a representation of an additional embodiment proposed for
the railroad sleeper of the present invention, this embodiment comprising a
contact surface protruding beyond the anchorage walls and further
disclosing double support points, wherein figure 12 (a) further discloses a
support groove, figure 12(b) discloses double support points, figure 12 (c)
discloses a plurality of support grooves, and figure 12 (d) discloses a
plurality
of anchorage teeth;
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Figure 13 is a representation of an additional embodiment
proposed for the railroad sleeper of the present invention, this
embodiment illustrating the embodiment in which the contact surface does
not protrude beyond the anchorage walls and further comprising double
support point that protrude into the hollow sector, wherein figure 13 (a)
further
discloses a support groove, figure 13 (b)
discloses double support points that protrude into the hollow sector, 13
(c) discloses a plurality of support grooves, and figure 13 (d) discloses a
plurality of anchorage teeth;
Figure 14 is a representation of the cross section of the
structural embodiment proposed for the sleeper illustrated in figure 13 (c),
highlighting its preferred dimensions;
Figure 15 is an additional representation of the cross section of a
structural embodiment proposed for the railroad;
Figure 16 is a representation of the cross section of a
structural embodiment proposed for the railroad sleeper, highlighting its
inner
and outer walls, and an intermediate layer;
Figure 17 is a representation of the cross section of an
additional embodiment of the railroad sleeper proposed in the present
invention, this embodiment further comprising the support surface illustrated
in figure 17 (a), figure 17 (b) further illustrates a plurality of support
grooves,
figure 17 (c) further illustrates a plurality of anchorage teeth, and the
protrusion of the support and contact surfaces beyond the anchorage
walls, and figure 17 (d) illustrates a plurality of anchorage teeth.
Figure 18 is a profile representation of a railroad network comprising the
railroad sleeper proposed in the present invention, further illustrating the
fixation blocks;
Figure 19 is a representation of the fixation of the railroad sleeper to
a fixation block and further making use of a fixation element arranged
transversely on the sleeper;
Figure 20 illustrates possible structural embodiments for the fixation
blocks to be used in conjunction with the railroad sleeper proposed in the
present invention;
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Figure 21 illustrates additional embodiments for the fixation blocks to be
used in conjunction with the railroad sleeper proposed in the present
invention;
and
Figure 22 illustrates the fixation of the railroad sleeper
5 proposed in the present invention by means of metallic plates, wherein
figure
21(a) illustrates the use of a smaller metallic plate as compared to the
metallic
plate illustrated in figure 21(b).
Figure 23 illustrates the fixation of the railroad sleeper shown in figure 19
by means of metallic plates, wherein figure 23 (a) 23 (b) illustrates
segmented
10 plates.
Figure 24 illustrates an embodiment wherein the railroad sleeper is made
only from the intermediate layer;
Figure 25 illustrates an embodiment wherein the railroad sleeper
comprises an intermediate layer and an inner layer;
Figure 26 illustrates an embodiment wherein the railroad sleeper
comprises an intermediate layer and an outer layer;
Figure 27 is an additional representation of the sleeper proposed in
present application;
Detailed description of the figures
[0055] The present invention relates to a railroad sleeper 1 (called also
sleeper
1).
[0056] Structurally and with reference to figure 1 to 27, the sleeper 1
proposed
in the present invention comprises a hollow sector 4, thus enabling the
ballast
used in the railroad network to penetrate and be compacted into the sleeper 1,
thus increasing the rigidity of the sleeper/ballast assembly.
[0057] Figures 1 to 27 illustrate preferred structural embodiments proposed
for
the railroad sleeper 1, all of them maintaining the characteristic referring
to the shaping of the hollow sector 4, as well as to the material (composite)
used. The particularities of each embodiment will be discussed hereinafter.
[0058] In reference to figure 1, the sleeper 1 proposed is used for fixing at
least
one pair of rails 2,2' of a railroad. It should be mentioned that the sleeper
1 is
suitable for use in simple railroad networks, provided with only one pair of
rails
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2, 2, as shown in figure 1 (a), or still it may be used at point of the
railroad
network that comprise a number of rails as shown in 1(b).
[0059] Figure 1 further makes reference to a contact surface 3 of the proposed
sleeper 1, said surface 3 being configured preferably as a plane surface for
arrangement of each rail 2, 2' of the railroad network.
[0060] Figure 2 illustrates a cross-sectional view of a first structural
embodiment
of the railroad sleeper illustrated in figure 1. One notes the contact
surface 3, preferably plane, from which anchorage walls 5 and 5' protrudes,
thus delimiting the hollow sector 4 mentioned before.
[0061] More specifically and with reference to figure 2, the hollow sector 4
is delimited from the contact surface 3 and by means of Anchorage walls 5, 5'.
Thus, a free portion adjacent to the anchorage walls 5, 5' is established,
opposite the contact surface 3. In other words, the embodiment proposed for
the railroad sleeper 1 establishes an inverted-U shape.
[0062] Thus, the free portion 17 should be understood as a (face) bored-
through (opened) portion of the hollow sector 4, this portion enabling the
ballast
of the railroad network to penetrate the railroad sleeper 1, and more
specifically
of the hollow sector 4.The lower portion of the anchorage walls 5, 5', that
is,
the portion that supports the sleeper 1 on the soil, is called support points
7,
7', such support points 7, 7' being opposite the points of association between
the contact surface 3 and the anchorage walls 5, 5'.
[0063] With reference to figures 3 and 4, the anchorage walls 5, 5'
delimit a first width Li of the railroad sleeper 1 proposed. As shown in
figure
3, and considering a preferred thickness E for the sleeper 1, the first width
Li
is delimited by the outermost portions (outer walls) of the anchorage walls
5,5',
that is, the portions that are not adjacent to the hollow sector 4.
[0064] With regard to the support points, they may assume different structural
embodiment for the proposed sleeper 1, as shown in figures 2 to 4.
[0065] The embodiment shown in figures 2 and 3 is referred to as simple
support points 7, 7', wherein the contact thickness of the sleeper 1 with the
ground is configured as the thickness E itself of the sleeper 1.
[0066] On the other hand, the embodiment shown in figure 4 and more
specifically in figure 4 (a) presents double support points 8, 8, wherein the
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contact thickness of the sleeper 1 with the ground exhibits dimensions larger
than the thickness E of the sleeper 1.
[0067] More specifically, the distance between the support points 7, T shown
in figure 3 and the support points 8, 8' shown in figure 4 (figure 4(b))
define a
second width L2 of the railroad sleeper. Thus, in the embodiment in which
the simple support points 7, 7' are used, the first width L1 has dimensions
equal to those of the second width L2, as shown in figure 3.
[0068] On the other hand, in the embodiment in which the double support points
8,
8' are used, the first width Li is smaller than the second width L2, as
shown in figure 4, more specifically in figure 4 (b).
[0069] Figure 5 illustrate a third embodiment valid for the proposed sleeper
1.
In this embodiment, one observes the elements discussed before in the
previous embodiments, such as contact surface 3 and anchorage walls 5, 5'.
[0070] The proposal shown in figure 5 makes use of simple support points 7,
7', thus establishing equal dimensions for the first and second widths Li and
L2, respectively (as shown in figure 6).
[0071] With a view to potentiate the support of the railroad sleeper 1
proposed
in the present invention, there is also, in the embodiment shown in figures 5
and 6, a groove 9 protruding from the contact surface 3 and toward the hollow
sector 4 of the railroad sector 4 of the railroad sleeper 1.
[0072] Figure 7 illustrates an additional structural embodiment for the
railroad
sleeper 2 proposed, this embodiment making use of the support grooves 9 and
of the double support points 8, 8'.
[0073] The support groove 9 may protrude through the whole height of the
hollow sector 4, as illustrated in the embodiments shown in figures 6
and 7, or, alternatively, the later may protrudes freely from the support base
3 and toward the hollow sector 4, as shown in figure 9.
[0074] In an additional structural configuration, the support grooves 9
further protrudes from at least one of the anchorage walls 5, 5' and toward
the
hollow sector 4 of the railroad sleeper 1.
[0075] Such an embodiment is shown in figure 10, where one observes that
this proposal comprises a support groove 9 protruding from the contact surface
3 and a support groove protruding from the anchorage walls 5 and 5'.
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[0076] An alternative structural embodiment for the railroad sleeper comprises
the support grooves 9 protruding from only the anchorage walls 5, 5', or
still protruding from only one of the Anchorage walls 5, 5'. Further, the
number
of support grooves 9 shown in the figures should not be considered a
!imitative
characteristic of the present invention.
[0077] The proposed railroad sleeper 1 further comprises a plurality of
anchorage teeth 12, such anchorage teeth 12 being preferably arranged on
at least one of the anchorage walls 5, 5'.
[0078] More specifically, the anchorage teeth 12 are arranged in the portion
of
the anchorage walls 5, 5' not adjacent the hollow sector 4, or still, for a
better
understanding, the anchorage teeth 12 are arranged on the outer walls of the
anchorage walls 5, 5'.
[0079] As can be seen in figure 11, the anchorage teeth 12 are configured as
recesses (channels) that preferably travel the whole length of the sleeper.
[0080] The anchorage teeth 12 do not interfere in the mechanical
characteristics of the sleeper 1, more specifically such teeth 12 provide
greater Anchorage of the sleeper 1 to the ballast, enabling the ballast to
penetrate into each of the anchorage teeth 12. Additionally, the
arrangement of the anchorage teeth 12 further provides saving of material
and optimization in the manufacture of the sleeper 1.
[0081] In alternative embodiments, the railroad sleeper 1 might be configured
so that the contact surface 3 would protrude beyond the anchorage walls 5, 5',
as shown in figure 12 of the present invention. In addition, the anchorage
walls
5, 5' may be parallel or orthogonal to the contact surface (3).
[0082] It is noted that such embodiments make use of double support
points 8, 8', wherein 12 (a) illustrates the sleeper 1 comprising a support
groove 9 protruding from the contact surface 3 and toward the hollow sector
4. On the other hand figure 12 (b) illustrates the sleeper without any support
groove 9 in its hollow sector 4.
[0083] Figure 12 (c) illustrates the sleeper 1 provided with support
grooves 9 from the contact surface 3 and also from the Anchorage walls 5,
5', and, finally, figure 12 (d) illustrates the sleeper 1 provided with a
support
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groove 9 from the contact surface 3 and also provided with Anchorage teeth
12.
[0084] In the embodiments in which the railroad sleeper 1 comprises double
support points 8, 8, such points 8, 8' may protrude out of the hollow sector 4
(as shown in figure 12), or alternatively such support points 8, 8' may
protrude
both out of the hollow sector 4 and into it, as shown in figure 13. In another
alternative embodiment, the support points 8, 8' might protrude only into the
hollow sector 4. In this case, the second width L2 of the sleeper would assume
a dimension equal to the first width L1.
to [0085] The embodiments shown in figure 13 are similar to those of figure
12
with respect to the arrangement of the anchorage grooves 9. One just
observes that in figure 13 the contact surface 3 does not protrude beyond the
anchorage walls 5, 5'.
[0086] The structural embodiments proposed for the railroad sleeper 1 having
been presented, their preferred embodiments are discussed hereinafter.
[0087] The thickness E of the sleeper 1 preferably assumes the value
of 2 centimeters (cm), so that values ranging from 1 to 4 centimeters
would be acceptable. In the embodiments where the sleeper 1 comprises
anchorage teeth
12, such teeth comprise a thickness Ei ranging from 0.2 to 0.5 cm.
[0088] Thus, and with specific reference to figure 11, each of the anchorage
teeth 12 is provided with a thickness Ei (thickness of the Anchorage teeth El)
that preferably range from 0.2 cm to 0.5 cm.
[0089] Further with reference to figure 11, the height hi of each anchorage
tooth 12 assumes preferable values from 0.5 to 2.0 cm.
[0090] For any of the embodiments proposed for the railroad sleeper 1, the
first
width Li preferably is equivalent to 24 cm, so that values in the range 18 to
30
cm would be acceptable.
[0091] The embodiments that make use of double support points 8, 8'
(protruding both into and out of the hollow sector 4) establish a second
preferred width L2 of 32 cm, so that values in the range 19 to 48 cm would be
acceptable, provided that obviously the second width L2 (double support
points)
is larger than the first width Li (simple support points).
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[0092] In the embodiment in which the double support points 8, 8 protrude only
into the hollow sector 4, the second width L2 will assume a value equal to the
first width Li.
[0093] With regard to the width of the double support points 8, 8, referred to
5 as third width L3 (figures 4, 8, 11 and 14), the later preferably is
equivalent to
6 cm (figures 4, 8 and 11), so that values in the range from 1.5 to 12cm would
be acceptable. In the case of the embodiment shown in figure 14, there is a
preferred third width L3 of 10 cm, wherein the range of 2 to 20 cm is
acceptable.
[0094] As to the height of the railroad sleeper 1 proposed in the present
10 invention, it is referred to as a first height H and preferably is
equivalent, for
any of the embodiments proposed, to 19 cm, so that values in the range from
14 to 20 cm would be acceptable.
[0095] In the embodiments that make use of the support groove 9,
such an element protrudes from the contact surface 3 at values in the range
15 from 0.5 to 19 cm, thus establishing a height of the Anchorage groove
h3, as
shown in figure 1. Obviously, the upper limit of this range represents the
embodiment in which such a groove extends along the whole height of the
hollow sector 4 (figures 5 and 6).
[0096] The width of the anchorage groove, referred to as L4, assumes preferred
values from 0.5 to 3.0 cm.
[0097] For support grooves 9 protruding from the anchorage walls 5, 5',
one should reduce the maximum limit of the height h3 to the value used
in the thickness E of the railroad sleeper 1.
[0098] The association of the anchorage walls 5, 5' with the contact
surface 3 and the double support points 8, 8' may be carried out
orthogonally, as shown in previous figures, alternatively it may be carried
out
by segments in curvature, as in the embodiment shown in figure 15.
[0099] The same thing occurs for the embodiment of the support groove 9,
which is suitable to be arranged orthogonally with respect to the contact
surface 3 and anchorage walls 5, 5', or alternatively it may be configured
from
segments in curvature.
[00100]
In order for the sleeper 1 to be capable of standing the stresses
of its application field, there is the need to use a material having a high
elastic
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16
module (high rigidity), having also high resistance to impact, resistance to
fatigue and high
market availability.
[00101] More specifically and in a preferred manner only,
the inner wall
13 and an outer wall 14 of the sleeper 1 are manufactured from the first
material,
preferably a polymeric material and more preferably a pure polymeric material.
[00102] In a further preferred embodiment, the contact
surface (3) and the
anchorage walls (5, 5') further establish an inner wall (13) and an outer wall
(14)
of the railroad sleeper (1), so that the inner wall (13) of the railroad
sleeper (1)
is manufactured from a first polymeric material; and the outer wall (14) of
the
railroad sleeper (1) is manufactured from the first polymeric material.
[00103] The inner and outer walls 13, 14 are delimited by
the contact
surface 3 and anchorage walls 5, 5, as better shown in figure 16.
[00104] In figure 16, the outer wall 14 is represented by
solid line. On
the other hand, the inner wall 13 of the railroad sleeper 1 is referenced by
dashed line.
[00105] On the other hand, the inner portion of the walls 13
and 14,
referred to as an intermediate layer 15, is preferably made from a composition
that preferably, but not exclusively comprises the first material, more
preferably
a composition of polypropylene with fiberglass, and still more preferably
a composition of polypropylene with a fiberglass mass preferably between
5% and 40% (by weight of the composition) and, even more preferably from
33% to 37% by weight of the composition of fiberglass.
[00106] It should be mentioned that the manufacture of the
inner
wall 13 and the outer wall 14 from the same material used in the manufacture
of the intermediate layer 15 (in this case, polypropylene) is just a preferred
characteristic of the present invention. Thus, the walls 13 and 14 might
be manufactured from a material other than that used in layer 15, as long as
obviously it provides the necessary adherence to the piece.
[00107] Such a preferred characteristic in the material of the proposed
sleeper 1, wherein the inner 13 and outer 14 walls are preferably made from
polypropylene and the intermediate layer 15 is made from a composition of
polypropylene with fiberglass, is valid for all the structural embodiments
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proposed for the railroad sleeper 1, and not only for the embodiment shown in
figure 16.
[00108] The thickness of one of the inner walls and outer
walls 13 and 4
preferably ranges from 0.005 to 0.05 cm, while the thickness of the inner
layer
15 may be achieved by subtracting the thickness E of the railroad sleeper by
the value of the thickness of one of the inner 13 and outer 14 walls.
[00109] It is important to point out that the use of the
composition of
polypropylene with fiberglass in the intermediate layer 15 should be
considered
just a preferred characteristic of the present invention, so that any material
(composition) having bending module higher than or equal to 5000MPa might
be used. Finally, one should understand that the bending module should be
measured (determined) according to the Standard ISO 178.
[00110] It is also important to highlight that the inner
wall (or inner layer)
may optionally not be included. Similarly, the outer wall (or outer layer) may
optionally not be present. Thus, the railroad sleeper 1 can be made only from
the intermediate layer without the inner and outer walls. Figure 24 shows an
embodiment wherein the sleeper is made only from the intermediate layer.
[00111] In the embodiment of figure 24, the railroad sleeper
1 would be
manufactured solely from the material of the intermediate layer 15, that is,
manufactured from a composition that preferably, but not exclusively,
comprises polypropylene and fiberglass, and more preferably a composition
comprising polypropylene and fiberglass with a mass range preferably
between 5% and 40% (by mass) and more preferably between 33% and 37%
by mass of fiberglass, in relation to the mass of the composition.
[00112] it is important to highlight that the manufacture of the sleeper 1
using the composition comprising polypropylene and fiberglass should be
considered only as a preferential feature of the present application, so that
any
material (composition) provided with a bending module greater than or equal
to 5000 MPa could be used in the manufacture of the sleeper 1, said bending
module must be measured (determined) in accordance with ISO 178. In a
preferred embodiment, said material is a polymeric composition. Said
polymeric composition can comprise polyolefins, polyesters, polyamides,
polyurethanes, and their mixtures, among other polymeric materials, with or
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without the addition of additives and/or fillers. In one or more embodiments
of
the present invention, said polymeric composition may be of renewable origin
or of fossil origin. In other embodiments, said polymeric composition may
comprise virgin polymers, recycled polymers or mixtures thereof.
[00113]
Consequently, present application teaches the possibility of
manufacturing the sleeper from a composition with a bending module greater
than or equal to 5000MPa, more preferably a polymeric composition, and more
preferably a polymeric composition comprising polypropylene and fiberglass.
[00114]
It is also noteworthy that said polymeric composition may include
fillers and additives that modify various physical and chemical properties
when
added to the polymeric composition, including one or more polymeric additives
such as pigments, flow accelerators, auxiliaries process, lubricants,
antistatic
agents, clarifying agents, nucleating agents, beta-nucleating agents, gliding
agents, antioxidants, antacids, light stabilizers such as HALS, IR absorbers,
anti-UV additives, bleaching agents, inorganic fillers, organic and / or
inorganic
dyes, anti-blocking agents, flame retardants, plasticizers, biocides and
adhesion promoting agents. Polymeric composition according to the present
invention can be loaded with charges which can include glass fibers, carbon
fibers, carbon black, silica powder, precipitated calcium carbonate, calcium
carbonate, talc, titanium dioxide, clay, polyhedral silsesquiloxane oligomeric
(POSS), calcium carbonate, metal oxide particles and nanoparticles, inorganic
salt particles and nanoparticles and mixtures thereof.
[00115]
The embodiment wherein the sleeper is made only from the
intermediate layer may be applied to any of the structural configurations
addressed in present application, including the configuration that comprises
the support surface 3'.
[00116]
In a possible embodiment of the present application, the inner
layer 13 could optionally be included in the railroad sleeper 1,1'. In this
case,
the sleeper 1 would be manufactured from a polymeric composition, preferably
comprising polypropylene and fiberglass and only its inner layer 13 would be
of a polymeric material, preferably included via coextrusion, as shown in
figure
25 of present application.
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[00117] Said polymeric material can be selected from
polyolefins,
polyesters, polyam ides, polyurethanes, and their mixtures, among other
polymeric materials. Said polymeric material can be of renewable origin or of
fossil origin, being able to comprise virgin polymers, recycled polymers or
mixtures of these. Preferably, said polymeric material can be selected from
polypropylene, polyethylene and their mixtures. More preferably, said
polymeric material is a polypropylene with or without the addition of
additives
and / or fillers.
[00118] Similarly, the outer layer 14 could also optionally
be included,
preferably via coextrusion. In this case, the sleeper 1 would be manufactured
from a polymeric composition, preferably comprising polypropylene and
fiberglass and only its outer layer 14 would be made of a polymeric material,
as shown in Figure 26. Said polymeric material can be selected from
polyolefins, polyesters, polyam ides, polyurethanes, and their mixtures, among
other polymeric materials. Said polymeric material can be of renewable origin
or of fossil origin, being able to comprise virgin polymers, recycled polymers
or mixtures of these. Preferably, said polymeric material can be selected from
polypropylene, polyethylene and their mixtures. More preferably, said
polymeric material is a polypropylene.
[00119] It is noteworthy that such polymeric materials used for the inner
or outer layers may also include fillers and additives previously mentioned.
[00120] Obviously, the embodiments of figures 25 or 26 can
be fixed
using any of the techniques addressed in present application.
[00121] For fixation of the proposed sleeper 1 (comprising
the inner and
outer walls or made only from the intermediate layer) to the rails 2, 2',
fixation
blocks 10 should be arranged in the hollow sector 4 of the sleeper 1. These
blocks have the primary function of enabling the installation of the tirefonds
and installation of the fixing devices that fasten the rails 2, 2' to the
sleeper.
More specifically, such blocks 10 prevent lateral movements of the railroad
and should be arranged in the portion of the sleeper 1 that is below the rails
2,
2', or, in other words, in the portion of the sleeper 1 opposite the point of
arrangement of the tracks on the contact surface 3.
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[00122] Figure 18 illustrates a profile view of a railroad
network in which
the sleeper 1 proposed in the present invention is used. In this figure, one
observes the sleeper 1, each of the rails 2, 2' fixed to the contact surface 3
by
means of the support plates 20 and tirefonds 21.
5 [00123] One further observes in the hollow sector 4 of the sleeper 1,
which, when fixed to a railroad network, enables the ballast of the railroad
to
penetrate the hollow sector 4 and, with the compaction of the ballast in the
hollow sector 4, greater rigidity of the ballast/sleeper system will be
achieved.
[00124] One further notes in figure 18 the fixing blocks 10
arranged below
10 each of the rails 2, 2', such blocks 10 being configured as solid blocks
and may
be made from wood, recycled material, concrete, polyethylene, polypropylene,
and still may be made from the same material used in the manufacture of the
sleeper 1, a composition of polypropylene with fiberglass. In the preferred
embodiment, the fixing blocks 10 are made from polyethylene.
15 [00125] Such fixing blocks 10 may be manufactured by different
processes, such as extrusion, intrusion, injection, pultrusion, and machining
processes that use massive blocks to obtain the final shape of the piece.
[00126] For better fixation of the blocks 10 to the sleeper
1, fixing
elements, preferably configured as hexagonal screws 26 might be arranged
20 transversely to the sleeper 1, as preferably represented in figure 19.
Figures
20 and 21 illustrate shapes proposed for the fixing blocks 10. It is important
to
mention that the structural embodiments proposed for the railroad sleeper 1
enable use of any of the embodiments of the fixing blocks 10.
[00127] The preferred dimensions of each of the proposed
fixing blocks
10 are described as follows:
[00128] With reference to figure 20(a), it preferably
represents a larger
base in 60 cm, so that values ranging from 50 to 80 cm would be acceptable.
[00129] The smaller base has a preferred value of about 40
cm, the
preferred height is of 15 cm, so that values in the range 13 to 17 cm would be
acceptable, and the preferred depth is equivalent to 20 cm, for both the
height
and the width.
[00130] The preferred values for the fixing block
illustrated in figure 20
(v) are of 15 x 13x 20 (width x height x depth), while for the embodiment
shown in
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figure 20 (c) there are preferred values of 7,5 cm for the smaller base and 15
cm for the larger base, the preferred depth being of 20 cm and the preferred
height being equivalent to 13 cm.
[00131] The proposal illustrated in figure 20 (d) and 20 (e)
disclose fixing
blocks 10 made by injection process. One notes that the blocks 10 illustrated
in such figures comprise a number of structures 27 designed for supporting
loads referring to the arrangement of railroad coaches.
[00132] Thus, the structures 27 combine resistance and
lightness and
establish a new possibility of arranging the fixing blocks 10. On further
notes
that the blocks 10 discloses in figures 20 (d) and (20 (e) further comprises
orifices 28 already designed for arrangement of appropriate screws. It should
be pointed out that the arrangement and the shape of the structures 27 should
not be limited to the embodiments shown in figures 20 (d) and 20 (e).
[00133] Further, any of the fixing blocks 10 discussed in
the present
invention and disclosed in figures 20 (a), 20 (b), 20 (c), 21(a) and 21(b)
might
be made by an injection process, thus configuring a structured block (with the
structures 27).
[00134] As to the dimensions of the fixing blocks
represented in figures
(d) and 20 (e), one may use preferably the same values already described
20 for the fixing block 10 shown in figures 20 (a).
[00135] The structural embodiment of the fixing block shown
in figure 21
(a) has larger base preferably at 60 cm, so that values in the range from
50 to 60 cm would be acceptable, its preferred height being of 15 cm, values
between 13 and 17 cm being acceptable, preferred depth being of 20 cm, while
the width of each of the bases adjacent the cavity 24 is preferably of 7.5 cm.
[00136] Finally, the proposal illustrated in figure 21(b)
exhibits the same
values for the larger base, height and depth as the values of the embodiment
21(a) and a preferred width of 15 cm for each of the smaller bases adjacent
the
cavity 24. One should mention that the above-mentioned dimensions were
given by way of example, without entailing any limitation of the present
invention.
[00137] Alternatively to the use of the fixing blocks 10,
one may fixe the
sleeper 1 by means of the already existing cast-iron plates 25 and still by
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22
means of the metallic plates 22 (preferably made of steel) fixed to the
existing
plates (plate 25) by means of conventional fixing element 23, such as screws,
press washers and nuts.
[00138]
Such fixing form is illustrated in figure 22, wherein figure 22 (a)
shows metallic plates 22 of smaller size as compared to that represented in
figure 22 (b). The embodiment shown in figure 22 (b), being arranged
completely between the rails of the railroad network, ends up increasing the
strength of the sleeper 1. It is further pointed out that the number of
metallic
plates 22 used should not restrict the number shown in figure 22.
[00139] In addition
to the structural embodiments proposes for the railroad
sleeper 1, where one establishes the hollow sector 4 and its free portion 17,
the present invention also proposes the shaping of a railroad sleeper 1
further
comprising a support surface 3.'
[00140]
Said support surface 3' is opposite the contact surface 3 and
adjacent the anchorage walls 5 and 5'. In this way, the hollow sector 4 of the
railroad sleeper 1' is delimited from the association of the contact surface 3
with the support surface 3' and by means of the anchorage walls 5, 5'. Thus in
the embodiments shown in figure 17, the sleeper 1' does not comprise the free
portion 17, since its hollow sector 4 is delimited also by the support surface
3.'
[00141] It should be
pointed out that the other characteristics and
embodiment proposed for the railroad sleeper 1 comprising the free portion 17
are also valid for the embodiment of the railroad sleeper 1' shown in figure
17
and that comprises the support surface 3'.
[00142]
For example, in the railroad sleeper 1' provided with the support
surface 3', is reference to the inner 13 and outer 14 walls is valid, as well
as
the use of the material and composition already mentioned when describing the
railroad sleeper 1. Further, the reference to the use of the support blocks 10
is
also valid for this embodiment. In this regard, figure 23 illustrates
additional
possibilities of fixing the railroad sleeper 1', wherein metallic plates 22'
are used
(the number of metallic plates 22' does not restrict the number represented in
the figures). The comment already made in figures 22 (a) about the increase in
the strength of the sleeper 1 is also valid for the representation of figures
23
(a).
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[00143]
Further, as one observes in the embodiment shown in figure
7 (b), the railroad sleeper 1' comprises support grooves 9, which protrude
from
at least one of the contact surfaces 3, support surface 3' and Anchorage walls
5.5'.
[00144] Further, as
observed in figure 17 (c), the contact surface
3 may protrude beyond the Anchorage walls 5, 5', together with the support
surface 3' proposed in this embodiment.
[00145]
One observes in figures 17 (c) and 17 (d) the proposal of
arranging the Anchorage teeth 12, just as proposed before for the embodiment
of the railroad sleeper 1 in which its hollow sector 4 does not comprise the
support surface 3.'
[00146]
In the embodiment shown in figure 17, the simple support
points 7, 7' should be understood as the proposal in which the contact
surface 3 and the support surface 3' do not protrude beyond the Anchorage
walls 5, 5', as shown in figures 17 (a), 17 (b) and 17 (d).
[00147]
On the other hand, the double support points 8, 8' should be
understood as the proposal in which the contact surface 3 and the support
surface 3' protrudes beyond the Anchorage walls 5, 5,' just as the embodiment
proposed in figures 17 (c).
[00148] In summary,
except for the difference in the shaping of the hollow
sector 4, the railroad sleeper 1' comprises all the characteristics mentioned
before for the railroad sleeper 1.
[00149]
It is important to mention that the embodiments illustrated in the
figures of the present invention are preferred embodiments for the railroad
1,1'.
[00150] Thus,
considering both the railroad sleeper 1 provided with a free
portion 17 and the railroad sleeper 1' with the support surface 3', it is
acceptable to propose an embodiment that is not explicitly shown in the
figures
presented, but that uses combinations of the characteristics set forth in the
figures.
[00151] For example,
considering the embodiment shown in figure 17, it
would be acceptable to propose a structural embodiment for the railroad
sleeper 1' that makes use of the Anchorage teeth 12 and of the support
grooves 9, even if the figures do not explicitly illustrate such an
embodiment.
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[00152]
The structural forms proposed for the railroad sleeper 1, 1 of the
present invention are obtained preferably by an extrusion/co-extrusion
process. Such a process is carried out by means of a conventional extruding
machine, provided, for example, with a feed point, thread cannon, matrix,
calibrator and velocity reducer.
[00153]
The structural embodiment of the extruding machine do
not represent the preferred aspect of the present invention, so that extruding
machines known from the prior art may be used to shape the railroad sleeper
1, 1,' proposed.
[00154] On the other
hand, determined parameters and extrusion-
process steps should be followed for correct shaping of the sleeper 1, 1',
such
parameters and steps being discussed hereinafter.
[00155]
Generally speaking, during the extrusion process, one
should perm it compaction of the composition (structure that forms the sleeper
1,1') used within the calibrator of the extruder and homogenous cooling of the
whole thickness of the piece.
[00156]
The process proposed comprises the initial step of adding the
composition used (preferably polypropylene with fiberglass) to the feeder of
the extruding machine and then regulate temperature parameter of the head
(melting zone) to meet the characteristics of the material.
[00157]
Concomitantly with the above step, one should add the first
pure polymeric material (pure polypropylene, without fiberglass) to an
extruding machine and melt it.
[00158]
Then, one should add in the extruding machine, at the same time
(at the same head), the (pure) molten polypropylene together with the
composition of polypropylene with fiberglass.
[00159]
After this, one should coat the composition of polypropylene with
fiberglass with pure polypropylene, thus establishing a structure with the
arrangement of the inner 13 and outer 14 walls in pure polypropylene and the
intermediate layer 15 in polypropylene and fiberglass. Thus one establishes a
structure similar to the extrusion process known as ABA, in which the first
layer
(layer A) consists of a determined material (in this case, pure
polypropylene),
the intermediate layer (layer B) consists of another material, in this case a
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composition of polypropylene with fiberglass, and the third layer consists
again of the material A, pure polypropylene.
[00160] It should be pointed out that the manufacture of the
inner
13 and outer 14 walls from the same material used in making the intermediate
5 layer 15 (in this case, polypropylene) is just a preferred characteristic
of the
present invention. Thus, the walls 13 and 14 might be mede from a material
other than that used in the layer 15, as long as obviously it provides the
necessary adherence to the piece.
[00161] Following the description of the proposed steps,
after melting the
10 structure within the cannon and the screw of the extruding machine, the
molten
structure is extruded within the matrix, said matrix having the main function
of
shaping the structure to a desired shape.
[00162] Subsequently, the structure, upon coming out of the
matrix,
passes through calibrator provided with a water-based cooling system. Said
15 cooling system aims at keeping the molten structure in its final shape,
besides
aiding in cooling the piece.
[00163] Upon coming out of the calibrator, the piece gets
into a system
for controlling the velocity of the extruding machine, thus limiting the
flowrate
of the process and enabling compaction of the structure 5 within the
calibrator,
20 thus preventing bubbles and loss of material. Finally, the molten
structure) is
cut into a desired size.
[00164] It is important to point out that the use of the
composition of
polypropylene with fiberglass in the intermediate layer 15 should be
considered only as a preferred characteristic of the process described, so
that
25 any material (composition) having a bending module higher than or equal
to
5000MPa might be used.
[00165] Additionally, the composition of polypropylene with
fiberglass
preferably used comprises, preferably, fiberglass in the range from 5% to 40%
by mass, and more preferably from 33% to 37% by mass of fiberglass.
[00166] Depending on the desired shape for the railroad sleeper 1, 1',
the calibrator of the extruder may be configured as a calibrator with or
without
vacuum. On calibrators without vacuum, one proposes a preferred length from
0.3 to 0.5 meters, while on a calibrator with vacuum, one proposes a preferred
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length between 1 and 4 meters and vacuum of the cooling chamber from 0 to
0.4 bar.
[00167]
It is pointed out that a calibrator without vacuum should be
preferably used for shaping the railroad sleeper 1 whose hollow sector 4 is
delimited by the free portion 17.
[00168]
On the other hand, a calibrator with vacuum is preferably used in
shaping the sleeper 1' whose hollow sector 4 is delimited by the support
surface 3.'
[00169]
Additionally, the following preferred parameters for the extruding
machine are proposed:
o temperature of the extruder preferably ranging from 220 C to 250 C;
o amperage of the extruder ranging from 25 to 350 A;
o pressure of the head preferably ranging from 15 5 to 70 bar;
o velocity of the extruding machine (velocity of the line) ranging from 0.1
to 0.5 meters/minute;
o rotation of the screw preferably ranging from 10 to 45 rotations per
minute (rpm);
o productivity of the extruding machine 5 preferably ranging from 0.1 to
0.8 k/meter;
[00170] Although the
process of shaping the railroad sleeper 1, 1' has
been referred to as an extrusion process, one should understand that such a
characteristic is just a preferred embodiment of the present invention, so
that
other processes might be used for structural shaping of the proposes sleeper
1, such as an intrusion, injection or pultrusion process.
[00171] It should
also be noted that in one or more embodiments, said
contact surface 3 can be a flat contact surface. In one or more embodiments,
the anchorage walls 5,5' are arranged orthogonally to the contact surface 3.
In
another embodiment, the anchorage walls 5,5' are parallel or substantially
parallel to each other. In another embodiment, the anchorage walls 5,5' are
vertical or substantially vertical with respect to the ground. It is
noteworthy that
a small inclination (maximum of 15 ) between each of the anchoring walls and
the vertical axis ("y" axis, perpendicular to the ground) would be acceptable.
This inclination could occur both for the interior of the sleeper or for its
exterior.
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Figure 27 illustrates the y-axis, where the x-axis must be understood as the
ground. It is therefore understood that said inclination would result in an
angle
of 90 15 in relation to the x axis.
[00172]
A preferred example of embodiment having been described, one
should understand that the scope of the present invention embraces other
possible variations, being limited only by the contents of the accompanying
claims, which include the possible equivalents.
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