TECHNICAL FIELD
[0001] The present invention relates to methods for producing spacers for concrete reinforcements.
BACKGROUND
[0002] Reinforcements for flat structures made of reinforced concrete are usually in the
form of steel reinforcement nets. Often, one or more reinforcement nets are provided
both at the top and the bottom of the flat structure, so that both tensile forces
and pressure forces can be absorbed in an optimum manner.
[0003] During construction, the reinforcement nets are usually kept at the desired distance
apart by means of spacers. Various types of spacer are known. One known spacer is
a lattice girder having a triangular cross section. Such spacers possess great strength
while at the same time using little material. However, they have the drawback that
they can easily tip over. A known spacer which does not tip over so easily consists
of two parallel and meandering longitudinal bars which are connected to each other
by means of transverse bars which are securely welded to the longitudinal bars at
right angles. However, these spacers are difficult to stack and cannot be readily
dragged across the bottom reinforcement net. There is therefore a need for new spacers.
There is also a need for new methods for producing spacers. Document
DE 22 14 532 A1 discloses a method for producing spacers for concrete reinforcements and concrete
structures. This document discloses to cut transverse bar portions on the construction
site after bending elongate latices to form spacers. Furthermore this document does
not disclose that transverse bars do not project or project by no more than 0.5 mm
over the top and bottom longitudinal bars.
SUMMARY
[0004] The present invention relates to methods for producing spacers for concrete reinforcements
and/or concrete structures.
[0005] The present invention provides a method for producing spacers for concrete reinforcements
and/or concrete structures comprising:
- (a) providing at least four parallel longitudinal bars in a plane, comprising:
- two peripheral longitudinal bars; and
- at least one punching groove consisting of a pair of mutually adjacent longitudinal
bars, positioned between said peripheral longitudinal bars;
- (b) placing transverse bars perpendicularly on and/or under the longitudinal bars,
and fastening the transverse bars to the longitudinal bars, so that a lattice structure
is produced;
- (c) optionally, cutting off any part of the transverse bars overhanging the peripheral
longitudinal bars;
- (d) cutting through or punching out of the transverse bar portions between the mutually
adjacent longitudinal bars of the punching groove, optionally except for two to five
of these transverse bar portions; thus producing two or more elongate lattices, optionally
connected to each other by means of two to five uninterrupted transverse bars; and
- (e) bending the two or more elongate lattices; in this case producing two or more
spacers for concrete reinforcements and/or concrete structures, each comprising two
or more parallel and identical meandering longitudinal bars, connected to each other
by transverse bars which are perpendicular to and laterally connected to the longitudinal
bars; in which the transverse bars do not project or project by no more than 0.5 mm
over the top and bottom longitudinal bars; and in which the spacers are optionally
connected to each other by means of two to five uninterrupted transverse bars.
[0006] In specific embodiments of the method described in the present application, step
(a) comprises unrolling and aligning at least four longitudinal bars in a plane; in
which step (a), (b), (c) or (d) furthermore comprises cutting the longitudinal bars
to a desired length. In further embodiments, a separate roll is provided for each
longitudinal bar.
[0007] In certain embodiments, step (b) comprises unrolling, aligning and cutting the transverse
bars from one or more rolls.
[0008] In specific embodiments, step (e) furthermore comprises turning each odd or even
lattice obtained in step (d).
[0009] In certain embodiments, the transverse bars of the spacers project by no more than
0.2 mm over the top and bottom longitudinal bars.
[0010] In specific embodiments, the method furthermore comprises welding the transverse
bars to the longitudinal bars. In specific embodiments of the method, two or more
longitudinal bars have a different diameter. In certain embodiments of the method,
two or more transverse bars have a different diameter.
[0011] In specific embodiments, the distance between the mutually adjacent longitudinal
bars of the punching groove is at most 1 cm.
[0012] In certain embodiments, the transverse bars are situated at a regular distance apart.
In specific embodiments, the spacers have a height of between 20 and 400 mm. In certain
embodiments, the spacers have a length of between 1 and 4 m.
[0013] In specific embodiments, the method furthermore comprises providing one or more longitudinal
bars in said plane, said longitudinal bars being positioned between one of the peripheral
longitudinal bars and the punching groove.
[0014] In specific embodiments, the longitudinal bars in step (a) form at least two bands,
each of which contains two or more longitudinal bars, in which each pair of neighboring
bands is separated from each other by a punching groove; and in which at least two
of the bands have a different width.
[0015] The method described herein makes it possible to produce spacers in a simple and
quick manner, in which the transverse bars do not project, or hardly project at all,
over the outer longitudinal bars. The spacers obtained in this way can more easily
be dragged across reinforcement nets than comparable existing spacers and are also,
in specific embodiments, easier to stack. The methods described herein furthermore
make it possible to produce spacers having a small height in a simple manner. The
combinations of mutually connected spacers described herein make it possible to store
and transport spacers more easily.
DESCRIPTION OF THE FIGURES
[0016] The following description of the figures of specific embodiments of the invention
is only given by way of example and is not intended to limit the present explanation,
its application or use. In the drawings, identical reference numbers refer to the
same of corresponding parts and features.
- Fig. 1
- shows a production unit (10) for carrying out a specific embodiment of the method
described herein.
- Fig. 2
- shows a lattice (5) obtained as an intermediate product according to a specific embodiment
of the method described herein.
- Fig. 3
- shows a perspective view (A), cross section (B) and detail (C) of a spacer (1) according
to specific embodiments.
- Fig. 4
- shows a perspective view (A), cross section (B) and detail (C) of a spacer (1') according
to specific embodiments.
- Fig. 5A
- shows a lattice (5) obtained as an intermediate product according to a specific embodiment
of the method described herein, for punching out transverse bar portions.
- Fig. 5B
- shows a lattice (5') obtained as an intermediate product according to a specific embodiment
of the method described herein, after the transverse bar portions have been punched
out.
- Fig. 5C
- shows a detail of a lattice (5') obtained as an intermediate product according to
a specific embodiment of the method described herein, after transverse bar portions
have been punched out.
[0017] In the description and figures, the following reference numerals are used:
1, 1' - spacer; 2, 3 - longitudinal bar; 4, 4' - transverse bar; 5, 5' - lattice;
6 - peripheral longitudinal bar; 7, 7', 8, 8' - longitudinal bar; 9 - overhang; 10
- production unit; 11, 12 - roll; 13 - guiding station; 14 - alignment station; 15
- welding station; 16 - trimming line; 17, 18 - punching line; 19 - cutting station;
20 - press; 21 - collecting station.
DESCRIPTION OF THE INVENTION
[0018] While potentially serving as a guide for understanding, any reference signs in the
claims shall not be construed as limiting the scope thereof.
[0019] As used herein, the singular forms "a", "an", and "the" include both singular and
plural referents unless the context clearly dictates otherwise.
[0020] The terms "comprising", "comprises" and "comprised of" as used herein are synonymous
with "including", "includes" or "containing", "contains", and are inclusive or open-ended
and do not exclude additional, non-recited members, elements or method steps. The
terms "comprising", "comprises" and "comprised of" when referring to recited components,
elements or method steps also include embodiments which "consist of" said recited
components, elements or method steps.
[0021] Furthermore, the terms first, second, third and the like in the description and in
the claims, are used for distinguishing between similar elements and not necessarily
for describing a sequential or chronological order, unless specified. It is to be
understood that the terms so used are interchangeable under appropriate circumstances
and that the embodiments described herein are capable of operation in other sequences
than described or illustrated herein.
[0022] The values as used herein when referring to a measurable value such as a parameter,
an amount, a temporal duration, and the like, is meant to encompass variations of
+/-10% or less, preferably +/-5% or less, more preferably +/-1% or less, and still
more preferably +/-0.1% or less of and from the specified value, insofar such variations
are appropriate to ensure one or more of the technical effects envisaged herein. It
is to be understood that each value as used herein is itself also specifically, and
preferably, disclosed.
[0023] The recitation of numerical ranges by endpoints includes all numbers and fractions
subsumed within the respective ranges, as well as the recited endpoints.
[0024] All documents cited in the present specification are hereby incorporated by reference
in their entirety.
[0025] Unless otherwise defined, all terms used in disclosing the concepts described herein,
including technical and scientific terms, have the meaning as commonly understood
by one of ordinary skill in the art. By means of further guidance, definitions for
the terms used in the description are included to better appreciate the teaching of
the present disclosure. The terms or definitions used herein are provided solely to
aid in the understanding of the teachings provided herein.
[0026] In the present description, an object is understood to be "elongate" if the length
of this object is greater than twice the width of this object; preferably, the length
is three, four or five times the width of the object.
[0027] As used herein, the term "perpendicular" may comprise a certain degree of deviation
from an exactly perpendicular orientation. More particularly, a first rod is deemed
to be positioned perpendicularly to a plane or second rod if the angle between the
longitudinal axis of the first rod and the plane, or the angle between the longitudinal
axes of the first and second rods, is/are between 89° and 91°; preferably between
89.5° and 90.5°; and most preferably 90°.
[0028] As used herein, the term "parallel" may comprise a certain degree of deviation from
an exactly parallel orientation. More particularly, a first rod is deemed to be positioned
parallel with respect to a plane or second rod if the angle between the longitudinal
axis of the first rod and the plane, or the angle between the longitudinal axes of
the first and second rod, is between 0.0° and 2.0°; preferably between 0.0° and 1.0°;
still more preferably between 0.0° and 0.5°, and most preferably 0°.
[0029] Reference throughout this specification to "one embodiment" or "an embodiment" means
that a particular feature, structure or characteristic described in connection with
the embodiment is included in at least one embodiment envisaged herein. Thus, appearances
of the phrases "in one embodiment" or "in an embodiment" in various places throughout
this specification are not necessarily all referring to the same embodiment, but may.
Furthermore, the particular features, structures or characteristics may be combined
in any suitable manner, as would be apparent to a person skilled in the art from this
disclosure, in one or more embodiments. Furthermore, while some embodiments described
herein include some but not other features included in other embodiments, combinations
of features of different embodiments are also envisaged herein, and form different
embodiments, as would be understood by those in the art. For example, in the appended
claims, any of the features of the claimed embodiments can be used in any combination.
[0030] The spacers are intended, in particular, to keep two or more parallel concrete reinforcements,
for example reinforcement nets for a flat structure, a desired distance apart. The
flat structure may be a horizontal structure, such as a floor, or a vertical structure,
such as a wall. The spacers may, for example, be used to keep reinforcement nets in
prefabricated (prefab) hollow walls spaced apart. Such walls typically comprise two
prefab concrete shells, in which each concrete shell comprises a reinforcement net.
These reinforcement nets are kept at a distance from each other by one or more spacers.
In this case, a hollow wall is obtained which can be filled with concrete at the building
site.
[0031] More particularly, the present invention provides a spacer for concrete reinforcements
and/or concrete structures comprising two or more parallel, mutually connected transverse
bars which are perpendicular to and laterally connected to the longitudinal bars.
The spacer has a meandering shape which makes a stable horizontal positioning of the
spacer on a flat surface possible. The spacer is furthermore characterized by the
fact that the transverse bars do not project, or hardly project at all, over the outer
longitudinal bars. As a result, the spacers can be dragged across reinforcement nets
in a simple and virtually unhampered manner. Below, these features will be explained
in more detail.
[0032] The spacer described herein comprises two or more longitudinal bars. The longitudinal
bars are positioned parallel with respect to each other, with a certain distance between
the longitudinal bars. The longitudinal bars are connected to each other by means
of transverse bars, so that a grate structure or lattice structure is obtained. As
used herein, the term "lattice structure" refers to an open frame formed by wires,
bars or the like which touch laterally or overlap, preferably in a regular pattern.
The transverse bars are positioned perpendicularly to the longitudinal bars, so that
a lattice structure with rectangular or square apertures is obtained. The lattice
structure may be regarded as a net-shaped structure; or a ladder structure in the
case of a spacer with only two longitudinal bars.
[0033] The spacer has a meandering shape. More particularly, the spacer is deformed to a
meandering shape at right angles to an imaginary band plane which is determined by
its parallel longitudinal bars in the straight position thereof. Such a shape may
be obtained by positioning the longitudinal bars in a plane in straight form, positioning
the transverse bars on and/or under the longitudinal bars, and bending the resulting
flat lattice structure at right angles to the plane determined by the lattice structure
to form a meandering shape (see below). The expression "meandering" or "meandering
shape" is understood to mean a wavy and/or zigzag-shaped bent configuration. Examples
of such a configuration are a trapezoidal bent configuration (see for example Fig.
3), a sinusoidal configuration, a triangular bent configuration, still other shapes,
and combinations thereof. The wavy and/or bent configuration makes it possible to
place the spacer in a stable position on a flat structure, such as a bottom reinforcement
net, by means of the bottom longitudinal bar. Indeed, the meandering shape of the
spacer ensures that the bottom longitudinal bar of the spacer forms a support surface
which provides sufficient stability to prevent the spacer from tipping over during
use thereof. The top longitudinal bar in turn forms a support surface on which a reinforcement
net can be placed.
In a simple form, the spacer only comprises two parallel longitudinal bars, more particularly
a bottom longitudinal bar and a top longitudinal bar. A spacer of this type is particularly
suitable for keeping concrete reinforcements a small distance apart, for example a
distance up to 400 mm, preferably a distance up to 200 mm. However, the spacers described
herein are not necessarily limited to these distances.
In specific embodiments, the spacer comprises three or more parallel longitudinal
bars, more particularly a bottom longitudinal bar, a top longitudinal bar, and one
or more intermediate longitudinal bars. This increases the strength of the spacer
and is particularly important for spacers of significant height, for example a height
of more than 200 mm. In the present application, the top and bottom longitudinal bars
are also referred to as "outer longitudinal bars". The distances between an intermediate
longitudinal bar and each of the two neighboring longitudinal bars may be equal or
different. In specific embodiments, the distance between two neighboring longitudinal
bars is always between 20 mm and 200 mm, preferably between 50 mm and 200 mm. With
the spacer described herein, the transverse bars do not project, or hardly project
at all, over the outer longitudinal bars. There is therefore no overhang, or hardly
any overhang at all, of the ends of the transverse bars over the top and bottom longitudinal
bars. More particularly, the transverse bars project at most 1.0 mm over the outer
longitudinal bars; preferably at most 0.5 mm; more preferably at most 0.2 mm; or at
most 0.1 mm; or at most 0.05 mm. The overhang of a transverse bar over a longitudinal
bar can be measured as the distance of the end of the transverse bar (on the side
of the respective longitudinal bar) compared to a plane which is perpendicular (90°)
to the longitudinal axis of the respective transverse bar, and the respective longitudinal
bar touches the outside of the spacer. An overhang of 0.5 mm thus means that if the
spacer is positioned on a plane, there is a distance of at most 0.5 mm from the bottom
longitudinal bar and the plane.
In specific embodiments, one or more transverse bars have straight ends. This means
that the transverse bars are cut along a plane perpendicular to their longitudinal
axis.
In specific embodiments, the ends of one or more transverse bars are oblique. This
means that the transverse bars are cut at an angle, preferably along a plane which
runs parallel to the longitudinal bars in the unbent state, and forms an angle of
30° to 50° with the transverse bars. Thus, the overhang of the transverse bars can
be minimized further. In further embodiments, all transverse bars have oblique ends.
[0034] In specific embodiments, one or more transverse bars may have a straight and an oblique
end.
Typically, the longitudinal bars and the transverse bars run along the entire length
and the entire height of the spacer, respectively. Due to the minimal overhang of
the transverse bars, the length of the transverse bars is therefore (virtually) equal
to the height of the spacer. The height of the spacer, more particularly the distance
between the outer (i.e. top and bottom) longitudinal bars, is usually between 20 mm
and 400 mm. For a large number of applications, a height of at most 200 mm is sufficient.
In a preferred embodiment, the spacer described herein thus has a height of between
20 mm and 200 mm, more preferably of between 50 mm and 200 mm.
However, the spacers described herein are not limited to such a height. In specific
embodiments, the height is between 50 mm and 400 mm, preferably between 200 mm and
400 mm, more preferably between 200 mm and 360 mm, for example 300 mm. In specific
embodiments, the height is approximately 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm,
80 mm, 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180
mm, 190 mm, 200 mm, 220 mm, 240 mm, 260 mm, 280 mm, 300 mm, 320 mm, 340 mm, 360 mm,
380 mm, or 400 mm.
The length of the spacer is usually between 100 cm and 400 cm, preferably between
100 cm and 300 cm, more preferably between 150 cm and 250 cm, for example 200 cm.
These values relate to the spacer in its bent (meandering) form. The length of the
spacer (and the longitudinal bars forming the spacer) in the corresponding unbent
state is usually between 10% and 100% greater than the length in the bent state, preferably
between 15% and 30% greater.
With the spacers described herein, the transverse bars are arranged perpendicularly
with respect to the longitudinal bars, with the transverse bars laterally touching
the longitudinal bars. Preferably, each transverse bar touches each of the longitudinal
bars of the spacer. In this way, a lattice structure comprising two or more parallel
longitudinal bars and a series of parallel transverse bars which run perpendicular
thereto is formed.
The distance between two neighboring transverse bars, measured along the longitudinal
bars, is usually between 50 and 300 mm, preferably between 50 and 200 mm, more preferably
between 100 and 150 mm. In specific embodiments, the transverse bars are placed at
regular distances apart. However, in specific embodiments, two or more neighboring
transverse bars may be placed closer together or further apart than other transverse
bars in order to take an uneven load into account.
[0035] The longitudinal bars and transverse bars are preferably made of steel. In certain
embodiments, the surface of the bars may not be smooth. For example, the surface may
be provided with coiled ridges. This increases the surface of the bars, which may
provide improved bonding of the steel and the concrete. However, this is not always
preferred. Accordingly, in certain embodiments, the surface of the longitudinal and/or
transverse bars may be smooth. In specific embodiments, the spacers may comprise a
combination of bars with a smooth surface and bars with a non-smooth or textured surface.
Typically, the diameter of the longitudinal and transverse bars is between 2.0 and
10.0 mm. In specific embodiments, the diameter of the longitudinal and transverse
bars is between 3.0 and 5.0 mm. The diameter of the longitudinal bars may be identical
to the diameter of the transverse bars or different.
The diameter of the transverse bars may be adapted to the height of the spacer. More
particularly, in the case of a higher spacer, transverse bars of greater strength,
and thus of greater diameter, are used. For example, in specific embodiments, if spacers
have a height of approximately 100 mm, transverse bars have a diameter of approximately
3.0 mm; whereas if spacers have a height of approximately 120 mm, the transverse bars
have a diameter of approximately 3.2 mm.
In specific embodiments, two or more transverse bars have a different diameter or
thickness. As a greater thickness typically leads to greater strength, this makes
it possible to take into account local variations in load while using a minimum of
material. More particularly, transverse bars at positions subjected to a high load
preferably have a larger diameter than the transverse bars at positions subjected
to a smaller load. In other embodiments, all transverse bars are of equal diameter.
In specific embodiments, two or more longitudinal bars have a different diameter or
thickness. More particularly, in specific embodiments, the spacers described herein
comprise three or more (parallel) longitudinal bars, with two or more longitudinal
bars having a different diameter or thickness. More particularly, the outer longitudinal
bars may have a larger diameter than the longitudinal bars which are situated in between
the outer longitudinal bars. This makes it possible to use less material, while still
ensuring the stability and strength of the spacers. However, this does not exclude
the possibility that all longitudinal bars may have the same diameter in other embodiments.
[0036] A combination of two or more spacers, as described above, is provided which are connected
to each other, more particularly by means of a number of uninterrupted transverse
bars. According to a specific embodiment of the method for producing spacers described
herein (see below), such a combination forms an intermediate product. The combinations
may furthermore be processed to form separate spacers, or may be offered as such.
A combination of mutually connected spacers is preferably used for spacers of small
height. Indeed, such low spacers are often quite difficult to handle, which may make
their transportation and storage difficult. The combinations described herein can
significantly facilitate the handling, transportation and storage of the spacers described
herein. The spacers can easily be separated from one another on site by cutting through
the uninterrupted transverse bars.
The combination described herein typically comprises a meandering lattice structure
which comprises two or more spacers, in which the spacers are positioned next to each
other, so that the transverse bars are in line with one another. The distance between
two neighboring spacers is usually between 3 mm and 20 mm, for example approximately
15 mm. In this case, most transverse bars are interrupted (i.e. they do not continue
in the space between two neighboring spacers), in which case the transverse bars of
each spacer do not project over the top and bottom longitudinal bars, or project by
no more than 1 mm, as described above. However, two or more transverse bars are not
interrupted, as a result of which the spacers in the combination are connected to
each other. All transverse bars are typically straight.
The longitudinal bars of the spacers are typically identical and placed parallel with
respect to each other.
In the combination described herein, the spacers are connected to each other by means
of at least two uninterrupted transverse bars, in order to ensure the rigidity of
the connection. In specific embodiments, the combination comprises more than two uninterrupted
transverse bars between each pair of neighboring spacers, but preferably not more
than five. A higher number of transverse bars may increase the strength of the combination,
but may also make it more difficult to separate the spacers. Typically, each pair
of adjacent spacers in the combination is mutually connected by at least 2 uninterrupted
transverse bars, and at most 3, 4, or 5 uninterrupted transverse bars. Furthermore,
each spacer preferably comprises at least 3, at least 4, or at least 5 interrupted
transverse bars (which do not project over the top and bottom longitudinal bars, or
project by no more than 1 mm) for each uninterrupted transverse bar.
In specific embodiments, the combination described herein comprises at least three,
at least four, at least five, or at least six spacers which are connected to one another.
In this case, the spacers are again positioned next to each other, so that the transverse
bars of the spacers are in line with one another, with each pair of adjacent spacers
being mutually connected by at least two uninterrupted transverse bars. In specific
embodiments, each uninterrupted transverse bar connects all the spacers in the combination
to each other. Typically, such an embodiment is the easiest to produce. However, this
is not imperative, and it is thus possible for one or more uninterrupted transverse
bars not to connect all spacers to each other, and for different pairs of spacers
in the combination to be connected to each other by means of different transverse
bars.
[0037] The uninterrupted transverse bars preferably comprise the transverse bars which are
situated at the ends of the spacers. An optional third uninterrupted transverse bar
is preferably situated approximately halfway between the spacers.
[0038] The separate spacers in the combination described herein typically have a height
of between 20 mm and 200 mm. However, it is possible for the combination to comprise
one or more spacers of a different height, for example between 200 mm and 400 mm.
The spacers connected to each other are typically of equal height, although it is
possible for the combination to comprise spacers of a different height.
[0039] An unbent combination as described above is provided, more particularly a (flat)
lattice structure which comprises two or more part-lattices, with each of the part-lattices
being mutually connected by means of two to five uninterrupted transverse bars. Such
a combination can often be bent more easily than separate part-lattices (see below),
and can thus form a significant intermediate product when producing the spacers described
herein.
[0040] The present invention furthermore provides methods for producing the spacers and/or
combinations of mutually connected spacers described herein.
[0041] More particularly, the present invention provides a method which comprises:
- (a) providing at least four parallel longitudinal bars in a plane, comprising
- two peripheral longitudinal bars; and
- at least one punching groove consisting of a pair of mutually adjacent longitudinal
bars, positioned between the peripheral longitudinal bars;
- (b) placing transverse bars perpendicularly on and/or under the longitudinal bars,
and fastening the transverse bars to the longitudinal bars, so that a lattice structure
is produced;
- (c) optionally, cutting off any part of the transverse bars overhanging (or projecting
from) the peripheral longitudinal bars;
- (d) cutting through or punching out of the transverse bar portions between the mutually
adjacent longitudinal bars of the punching groove, optionally except for two to five
of these transverse bar portions; thus producing two or more elongate lattices, optionally
connected to each other by means of two to five uninterrupted transverse bars; and
- (e) bending the two or more elongate lattices; in this case producing two (or more)
spacers for concrete reinforcements as described herein, in which the transverse bars
do not project or project by no more than 0.5 mm over the top and bottom longitudinal
bars, connected to each other by means of two to five uninterrupted transverse bars.
[0042] This method makes it possible to produce spacers, in which the transverse bars do
not overhang or overhang only slightly, the outer longitudinal bars, and in an efficient
and material-saving manner. The spacers obtained in this manner can be dragged across
reinforcement nets in a simple and virtually unhampered manner. Below, these steps
will be explained in more detail.
[0043] The method described herein comprises in a first step (a) providing at least four
parallel longitudinal bars, usually in a plane. The four or more longitudinal bars
comprise two peripheral longitudinal bars and at least one pair of mutually adjacent
(neighboring) longitudinal bars different from the peripheral longitudinal bars. More
particularly, at least one pair of mutually adjacent longitudinal bars (different
from the peripheral longitudinal bars) forms a punching groove. A punching groove
forms a line of separation where the transverse bars are cut and/or punched, so that
the peripheral longitudinal bars and the longitudinal bars of the punching groove
form the outer longitudinal bars of the resulting spacers (see below). Any other longitudinal
bars form intermediate longitudinal bars of the spacers. The punching grooves divide
the parallel longitudinal bars into two or more bands which are separated from each
other by punching grooves, in which a separate spacer can be formed from each band.
[0044] In specific embodiments, at least five parallel longitudinal bars are provided, preferably
six or more parallel longitudinal bars. In specific embodiments, six parallel longitudinal
bars are provided, with one or two adjacent pairs of longitudinal bars forming one
or two punching grooves, respectively. In specific embodiments, eight or more parallel
longitudinal bars are provided, in which case at least three punching grooves are
formed.
[0045] The longitudinal bars are typically positioned at a distance with respect to each
other, corresponding to the distance between the neighboring longitudinal bars in
the spacers described herein. However, each pair of mutually adjacent longitudinal
bars which forms a punching groove is preferably placed as close together as possible,
in order to reduce the loss of material during separation of the spacers (see below).
In specific embodiments, the distance between a pair of mutually adjacent longitudinal
bars which forms a punching groove is at most 20 mm and this distance is also referred
to herein as the width of the punching groove. Preferably, each punching groove has
a width of 0 mm to 20 mm, preferably between 0 mm and 15 mm, more preferably between
0 mm and 10 mm.
If the portions of the transverse bars are not cut but punched in the punching groove
and the punching groove is too narrow, this may result in accelerated wear of the
dies which are used for the punching-out operation. Preferably, the distance between
a pair of mutually adjacent longitudinal bars which forms a punching groove is at
least 3 mm in such embodiments. In specific embodiments, this distance is approximately
15 mm. Such a distance may ensure minimal wear and little loss of material.
In specific embodiments, the distance between two mutually adjacent longitudinal bars
is between 20 mm and 400 mm, preferably between 20 mm and 200 mm, more preferably
between 50 mm and 200 mm (except between the mutually adjacent longitudinal bars which
form a punching groove, as described above).
As has been described above, the parallel longitudinal bars together form two or more
bands, in which case each pair of neighboring bands is separated from each other by
a punching groove. Each band contains at least two longitudinal bars. The distance
between the outer pair of longitudinal bars of a band is also referred to herein as
the "width" of the respective band. This width determines the height of the spacer
which can be obtained from the respective band by means of the method described herein.
In specific embodiments, two of the two or more bands are a different width. This
makes it possible to produce two or more types of spacers of a different height simultaneously
using one installation. Thus, it is possible to avoid the installation having to be
completely changed over for each new height. This saving in changeover time makes
it possible to achieve a more efficient and rapid production.
In specific embodiments, the longitudinal bars form at least three, at least five,
at least eight, at least ten, or at least twelve bands which are separated from each
other by punching grooves, in which case at least two bands have a different width.
[0046] In specific embodiments of the method described herein, providing the at least four
parallel longitudinal bars comprises unrolling and (straightening and) aligning these
longitudinal bars in a plane.
In a preferred embodiment, each of the four or more longitudinal bars comes from a
separate roll. This can increase the production rate and makes it possible, if desired,
to combine different kinds of longitudinal bars, for example longitudinal bars of
different diameters. In specific embodiments, the four or more longitudinal bars thus
comprise at least two longitudinal bars of different diameters. Thus, it is possible
to produce spacers which comprise two or more longitudinal bars of a different diameter
or thickness, as described above.
When the longitudinal bars are unrolled from one or more rolls, the method described
herein furthermore also comprises cutting the longitudinal bars to a desired length.
This cutting may take place immediately after unrolling has taken place or in a subsequent
stage of the production process, for example after a number of transverse bars have
been welded onto the longitudinal bars. More particularly, this cutting off may be
effected in step (a), (b), (c), or (d). In specific embodiments, this takes place
after fastening the transverse bars in step (d), and before bending the lattices in
step (e). The desired length depends on the desired length of the spacers, and is
usually between 115 cm and 600 cm, preferably between 200 cm and 300 cm, for example
230 to 260 cm.
[0047] The method described herein furthermore comprises (b) perpendicularly positioning
transverse bars on and/or under the longitudinal bars, and fastening the transverse
bars to the longitudinal bars, so that a lattice structure is obtained. The sequence
of positioning the transverse bars and the longitudinal bars is not critical for the
method described herein. In specific embodiments, the longitudinal bars are first
positioned along a specific length, following which one or more transverse bars are
positioned on and/or under the longitudinal bars. In other embodiments, one or more
transverse bars are positioned first, following which the longitudinal bars are positioned
on and/or under the transverse bars. In a preferred embodiment, the method described
herein is carried out as a (partly) continuous process. In this case, longitudinal
bars may, for example, be unrolled from a roll and the transverse bars are positioned
on and/or under the longitudinal bars as the longitudinal bars are being unrolled.
The transverse bars run parallel to one another and are perpendicular to the longitudinal
bars, and laterally touch the longitudinal bars. In this case, a lattice structure
is formed. In specific embodiments, all transverse bars are on the same side of the
plane which is determined by the longitudinal bars. However, it is provided that,
in specific embodiments, transverse bars may be present on both sides of this plane.
Thus, it is for example possible to ensure that the transverse bars are mainly or
only situated on the convex side of the bending; or are mainly or only situated on
the concave side of the bending during the bending operation in step (e) (see below).
In specific embodiments, the transverse bars are positioned and fastened to the longitudinal
bars one by one. In this case, a subsequent transverse bar is only positioned once
the preceding transverse bar has been fastened. In other embodiments, several successive
transverse bars are positioned before the transverse bars are fastened.
The transverse bars are preferably fastened to the longitudinal bars by welding. More
particularly, bars are welded together at the points of contact between the bars.
In specific embodiments of the invention described herein, positioning the transverse
bars comprises the unrolling, (straightening,) aligning and cutting of the transverse
bars from one or more rolls. In specific embodiments, the transverse bars come from
one and the same roll. This is eminently suitable for producing spacers which only
feature one type of transverse bar. If only a single roll is used for the transverse
bars, the positioning and fastening of the transverse bars takes place step by step,
for example transverse bar by transverse bar.
In specific embodiments, the transverse bars come from two or more rolls. This has
the advantage that different types of transverse bars can be used, for example transverse
bars of different diameters. In specific embodiments of the method described herein,
two or more transverse bars accordingly have a different diameter.
[0048] Neighboring transverse bars are usually placed apart at a distance of between 50
and 300 mm, preferably of between 50 and 200 mm, more preferably of between 100 and
150 mm. In specific embodiments, the transverse bars are placed at regular distances
apart. However, in specific embodiments it is provided that specific neighboring transverse
bars are placed closed together or further apart than other neighboring transverse
bars.
[0049] In specific embodiments, the transverse bars already have the desired length before
they are positioned, so that there is no or hardly any overhang of the transverse
bars over the two peripheral longitudinal bars after the transverse bars have been
fastened. In other embodiments, the transverse bars are longer, so that there initially
is an overhang. In specific embodiments, the method described herein thus furthermore
comprises a step (c) which comprises cutting the transverse bar overhang over the
peripheral longitudinal bars.
In a preferred embodiment, there is an initial overhang during the positioning of
the transverse bars, and the overhang is cut afterwards. This makes it possible to
increase the production rate, since accurate placement of an accurately dimensioned
transverse bar can usually be carried out less quickly than accurately cutting off
an overhang.
[0050] As described above, the longitudinal bars of the punching groove or punching grooves
form the outer longitudinal bars of the eventual spacers. In order to separate the
spacers from each other, the transverse bars are cut and/or punched between the adjacent
horizontal longitudinal bars of each punching groove.
In specific embodiments, the portions of transverse bars can be cut through or cut
out in the punching grooves. Cutting such a transverse bar portion may be effected
by means of one or two cutting operations. A single cutting operation typically suffices
when the width of a punching groove is sufficiently small (at most 1 mm), so that
the transverse bars project by less than 0.5 mm over the transverse bars after the
cutting operation. Wider punching grooves typically require two cutting operations
to prevent the transverse bars from projecting by more than 0.5 mm.
In specific embodiments, with the method described herein, the pieces of transverse
bar are punched out between each pair of longitudinal bars forming a punching groove.
The expression "punching out" or "punching" is understood to mean that a portion of
transverse bar is cut out of the transverse bar between two adjacent horizontal longitudinal
bars of a punching groove in a single operation. The removal of a portion of a transverse
bar then does not comprise two separate cutting operations. This operation may be
regarded as being analogous to punching or perforating, in which an opening is produced
in a plate.
The cutting through and/or punching out is carried out in such a way that there is
no overhang, or hardly any overhang, of the transverse bars over the outer longitudinal
bars of the resulting lattices and the spacers formed therefrom (see below) after
the cutting-through and/or punching-out operation. More particularly, the remaining
overhang is at most 0.5 mm; preferably at most 0.2 mm; or at most 0.1 mm; or at most
0.05 mm. Cutting through and/or punching out may be carried out in such a manner that
transverse bars with straight ends and/or oblique ends are formed, as described above.
In specific embodiments, all transverse bar portions are cut through or punched out
in the punching groove or punching grooves. As a result of the cutting and/or punching,
two or more separate (flat) lattices are thus formed which are bent in a subsequent
step to form a spacer, as described herein. In specific embodiments, in order to effect
the bending, each even or each odd lattice obtained in step (d) is turned or turned
back, so that corresponding transverse bars of subsequent lattices are situated in
each case at opposite sides of the lattices. As a result thereof, it is possible to
stack the resulting spacers closer on top of each other. Turning is preferably carried
out by rotating the lattice through 180° about the transverse axis or longitudinal
axis, but may be effected by means of any combination of translational movements and/or
rotations having the same effect.
In specific embodiments, all the transverse bar portions are cut through and/or punched
out in one or more punching grooves, except two to five transverse bar portions which
are not interrupted. By cutting and/or punching, a lattice structure is thus formed
which comprises two or more mutually connected (flat) part-lattices which are bent
in a subsequent step to form a combination of spacers, as described herein. This may
significantly facilitate the bending of spacers of a small height. In specific embodiments,
two or more punching grooves are provided in step (a). In such embodiments, it is
possible to punch out all the transverse bar portions in specific punching grooves,
and to not interrupt two to five transverse bar portions in other punching grooves.
Thus, for example, a large lattice structure can be subdivided into part-lattices,
in which case each part-lattice may in turn be bent to form a combination of mutually
connected spacers as described above.
In a preferred embodiment, the lattice comprises two or more punching grooves, and
no transverse bar portions are cut through and/or punched out with two to five transverse
bars in the lattice and, with all the other transverse bars, all the transverse bar
portions are cut through and/or punched out in the punching grooves. Thus, all part-lattices
are connected to each other by means of the same transverse bars.
[0051] In step (e), the (part-)lattices obtained in step (d) which may be connected to each
other are bent by means of two to five uninterrupted transverse bars as described
above. Typically, the lattices are bent at right angles to the plane determined by
the original lattice obtained in step (d), in such a way that each of the bent longitudinal
bars is in a plane which is perpendicular to the plane determined by the original
lattice. In other words, the longitudinal bars are bent in an identical manner, each
in a plane perpendicular to the longitudinal bars. In this case, a meandering spacer
and/or a combination of mutually connected meandering spacers are obtained, as described
above.
[0052] In an optional further step, the spacers and/or combinations of mutually connected
spacers are stacked and tied together, preferably in packs of 10 to 50 spacers or
combinations. The stacking and/or tying together may be carried out manually or may
be automated.
As described above, in specific embodiments a combination of mutually connected spacers
can be obtained in step (e). These can be cut at the factory or on site to form separate
spacers as described herein. In specific embodiments, the method described herein
thus comprises:
(f) cutting through and/or punching out any remaining transverse bar portions between
two or more mutually connected spacers.
[0053] The method described above for producing spacers allows for efficiently producing
the spacers described herein with a minimum of material loss. However, the spacers
may also be manufactured by simply providing a lattice comprising two or more parallel
longitudinal bars and a plurality of transverse bars, cutting off any part of the
transverse bars overhanging the peripheral longitudinal bars, and bending the lattice,
thereby obtaining a spacer as described herein comprising two or more longitudinal
bars. Accordingly, further provided herein is a method for producing a spacer, said
method not being covered by the invention and comprising:
- (A) providing two or more parallel longitudinal bars in a plane, including two peripheral
longitudinal bars;
- (B) placing transverse bars perpendicularly on and/or under the longitudinal bars,
and fastening the transverse bars to the longitudinal bars, so that a lattice structure
is produced;
- (C) optionally, cutting off any part of the transverse bars overhanging (or projecting
from) the peripheral longitudinal bars; and
- (D) bending the lattice structure; thereby obtaining a spacer for concrete reinforcements
as described herein.
[0054] In this method, step (C) may be performed prior or after step (D). In preferred embodiments,
step (C) is performed prior to step (D).
[0055] In specific embodiments, step (A) may comprise unrolling and (straightening and)
aligning the longitudinal bars in a plane. In a preferred embodiment, each of the
four or more longitudinal bars comes from a separate roll. This can increase the production
rate and makes it possible, if desired, to combine different kinds of longitudinal
bars, for example longitudinal bars of different diameters. In specific embodiments,
the four or more longitudinal bars thus comprise at least two longitudinal bars of
different diameters.
[0056] When the longitudinal bars are unrolled from one or more rolls, the method described
herein furthermore also comprises cutting the longitudinal bars to a desired length.
This cutting may take place immediately after unrolling has taken place or in a subsequent
stage of the production process, for example after a number of transverse bars have
been welded onto the longitudinal bars. More particularly, this cutting off may be
effected in step (A), (B), or (C). In specific embodiments, this takes place after
fastening the transverse bars in step (B), and before bending the lattices in step
(D). The desired length depends on the desired length of the spacers, and is usually
between 115 cm and 600 cm, preferably between 200 cm and 300 cm, for example 230 to
260 cm.
The details of steps (B) and (C) of the method as described above apply,
mutatis mutandis, to steps (b) and (c), of the method described prior in this application.
[0057] The present invention will be illustrated by the following non-limiting embodiments.
EXAMPLES
[0058] Fig. 1 is a representation of a production unit (10) for carrying out a specific
embodiment of the method described herein. The unit is adapted for unrolling six transverse
bars from six rolls (11). By means of a guiding station (13), the longitudinal bars
are taken to an alignment station (14) where the bars are positioned parallel to each
other in a plane.
The transverse bars are unrolled and cut from a single roll (12) and are positioned
perpendicularly to the transverse bars one by one and welded onto the transverse bars
in a welding station (15). This is typically carried out at a rate of approximately
two transverse bars per second.
[0059] In this case, a continuous lattice (5) is obtained, as illustrated in Fig. 2. The
lattice (5) contains six parallel longitudinal bars, of which two are peripheral longitudinal
bars (6), and two pairs of adjacent horizontal longitudinal bars (7 and 7'; 8 and
8'), with each pair (7 and 7'; 8 and 8') forming a punching groove. The distance between
each pair of longitudinal bars forming a punching groove is smaller than the other
distances between the longitudinal bars. Thus, three bands (a, b, c) are created,
with a spacer being formed from each band.
[0060] The lattice is processed further in a first trimming line (16), in which the overhang
of the transverse bars over the outer longitudinal bars (6) is accurately cut off
on both sides. The overhang of the transverse bars is indicated in Fig. 2 by the hatched
rectangles (9). Thereafter, the transverse bar portions between the first pair of
longitudinal bars (7, 7') which forms a punching groove are punched out in a first
punching station (17) and the transverse bar portions between the second pair of longitudinal
bars (8, 8') are punched out in a second punching station (18). Finally, the longitudinal
bars (6, 7, 7', 8, 8') are cut at an equal distance in a cutting station (19). Three
lattices are obtained in each case, corresponding to the three bands (a, b, c).
[0061] The lattices are transported to a press (20), where they are bent to form a spacer
as illustrated in Figures 3 and 4. Optionally, each even or odd lattice is turned
for bending, so that the lattices can be stacked more easily.
[0062] Fig. 3A is a representation of a spacer (1) according to a specific embodiment of
the present invention. The spacer (1) comprises two parallel and identical meandering
(outer) longitudinal bars, more particularly a top longitudinal bar (2) and a bottom
longitudinal bar (3). The longitudinal bars (2, 3) are connected by transverse bars
(4) which are situated perpendicular to the longitudinal bars. There is no overlap
of the transverse bars (4) beyond the longitudinal bars (2, 3). Each of the longitudinal
bars is bent in a plane, so that the bottom longitudinal bar (3) permits stable positioning
of the spacer (1) on a reinforcement net and the top longitudinal bar (2) permits
stable positioning of a reinforcement net on the spacer (1).
Fig. 4A is a representation of a spacer (1') similar to the spacer illustrated in
Fig. 3A, except that the transverse bars in the spacer (1) in Fig. 3A are situated
on the rear side of the spacer, while the transverse bars in Fig. 4A are situated
on the front side of the spacer (1'), as is also clear from the cross section along
line A-A' and B-B' (Figures 3B and 4B), and the detailed view (Figures 3C and 4C).
By alternately stacking the spacer (1) from Fig. 3 and the spacer (1') from Fig. 4,
the spacers (1, 1') can be stacked closer against one another than would be the case
if spacers of the same type were to be stacked on top of one another.
[0063] In a last step, the spacers are collected and tied together in a collecting station
(21).
[0064] In specific embodiments, the method described herein can be used to produce combinations
of mutually connected spacers. This is illustrated in Fig. 5A-C. The arrows in Fig.
5A and 5B show the direction of production.
Fig. 5A shows a lattice (5) with 18 parallel transverse bars (4, 4') which are positioned
perpendicularly to 24 parallel longitudinal bars (6, 7, 7'). However, the person skilled
in the art will understand that the method described herein can also be carried out
using more or fewer transverse bars and longitudinal bars. The longitudinal bars (7,
7') form 11 punching grooves, so that the lattice contains 12 part-lattices, each
of which can be bent to form a spacer with two longitudinal bars. However, due to
their large length/width ratio, bending such part-lattices is very laborious. Likewise,
the handling, transportation and storage of the eventual spacers is not easy.
Therefore, it may be advantageous, with the punching station (17) as described above,
not to punch out all transverse bar portions in the punching grooves. It is possible,
for example, to allow specific transverse bars to remain intact, as illustrated in
Fig. 5B and 5C. These figures show a lattice (5'), in which all the transverse bar
portions have been punched out in the punching grooves, except for four transverse
bars (4'): two in the centre of the lattice and two at the ends thereof. Thus, the
part-lattices and the resulting spacers can easily be bent to form a combination of
spacers (1). After bending, the spacers (1) can readily be separated from one another
by cutting through or punching out the remaining portions of transverse bars (4')
between the punching grooves. Thus, separate spacers (1) are obtained, each having
two longitudinal bars (2, 3).