[0001] This invention relates to a device for bending in one operation a series of parallel
bars of a net, consisting of longitudinal bars and cross bars welded thereon, according
to the principle of the four point disposition meaning that use is made of two opposite
bending moments, the points of action of which displace in such a manner that no other
forces occur during the bending operation than said moments.
[0002] Bending machines for bending the cross bars destined for forming a net are known.
Machines for bending the cross bars of a net already formed and consisting of longitudinal
bars and cross bars welded thereon also exist.
[0003] The machines just referred to correspond to the type wherein the bar is bent by a
device wherein the bar is treated according to the principle of the three or of the
four point disposition. Two variants of this three point disposition exist which are
described hereinafter.
Variant 1
[0004] The bar can indeed be bent by exerting a pushing force with a movable cam between
two fixed cams supporting the bar.
[0005] The bar bends around this middle movable cam over a bending diameter equal to the
one of this movable cam.
Variant 2
[0006] In case of a three point disposition the movable cam may act on one side of the two
fixed cams (one above and one underneath the bar). The bent bar shows then a bending
diameter equal to the one of the fixed cam on the side of the movable cam.
[0007] Bending machines for one bar based on this three point disposition have the advantage
of permitting different bar diameters to be bent without adjustment. However, the
drawback is that only one bar can be bent at the same time and that another bending
diameter requires another cam involving the necessary adjustment time.
[0008] In bending machines based on the four point disposition two opposite moments are
realised with two combinations of two opposite pushing forces. The movements of the
points of action of this pushing forces result from the bending of the bar. The bending
diameter of the bar is a function of the distance between the two middle points of
action and the realised bending angle.
[0009] Bending machines for one bar based on the four point disposition have the advantage
of permitting bars with different diameters to be bent without adjustment whilst adjusting
to another bending diameter requires little time. The drawback of known machines operating
according to this principle is the fact that they can bend only one bar.
[0010] A clear picture of an apparatus for bending one bar, built according to this principle
of the four point disposition, is given by the European patent 0 226 167.
[0011] Machines known hitherto for bending a net operate according to the principle described
hereinabove under "Variant 2". Such machines have therefore the advantage of permitting
indeed to bend an entire net, whilst no adjustment of the pushing cams is required
as long as the bending diameter of the bar is not changed.
[0012] The drawback of such machines is clearly that for each changed bending diameter an
adjustment of the pushing cams is required. Bending machines based on this principle
operate only for nets having an identical cross bar diameter. When the net has different
cross bar diameters, serious bending errors appear.
[0013] The invention has therefore as object to provide a device, the operation of which
is based on the four point disposition, and which allows to bend entire nets with
non-identical bar diameters without adjustment of the pushing cams as a result of
automatic adaptation of certain essential components to the different bar diameters.
[0014] To allow this according to the invention, it consists of bending means which are
movable with respect to a frame and extend perpendicular or substantially perpendicular
with respect to the bars to be bent, with four pressure pieces being successively
mounted both on the frame and on the movable bending means, the two inner pieces of
which being situated on the one side and the two outer pieces on the other side with
respect to the longitudinal axis of the bar and some of these pressure pieces may
be movable with respect to the longitudinal axis of the bar.
[0015] Still according to the invention said bending means consist of a bending table with
pressure pieces connected thereto.
[0016] In a particularly advantageous embodiment of the invention said bending table is
hingedly connected to said frame.
[0017] The device is constructively designed in such a manner that it comprises at least
one, but preferably two bending benches which are movable to and away from each other.
[0018] Other details and advantages of the invention will become apparent from the following
description of a device for bending the bars of a net according to the invention.
The description is only given by way of example and can in no way be interpreted as
a limitation of the invention. The referral numerals relate to the figures annexed
hereto.
[0019] Figure 1 is a schematic side view with partial cross sections of a device according
to the invention in double disposition.
[0020] Figures 2 and 3 illustrate also schematically the principle of so-called four point
disposition, of which the device according to the invention forms a particularly attractive
realisation.
[0021] Figure 4 illustrates according to a perspective view the arrangement of the pressure
means on the frame and on the bending table.
[0022] The Figure 1 annexed to this description shows thus clearly a device according to
the invention in a possible double disposition of two bending benches. On both sides
of the longitudinal symmetrical plane the device comprises a frame 1, respectively
1'. In case of such a double disposition the frames 1 and 1' are removable from each
other. To this end it is sufficient that one of these frames, for example frame 1,
is a fixed frame, whereas frame 1' is movable by means which do not pertain to the
invention, in such a manner that all characteristics of the bent net can be met.
[0023] For a good understanding of the invention it has to be noted very clearly that, in
case of a possible omission of the frame 1 together with the movable components connected
thereto and characterising the device, the net can rest on a fixed component pertaining
to the device, for example a supply table. Such an arrangement will not be described
here further into detail.
[0024] To a frame 1, respectively 1' is mounted a hinged bending table 2, 2'. The hinge
axis of the bending tables 2, 2' is referred to by references 3, 3'.
[0025] Each bending table 2, 2' may take in any position. The bending table 2 can take in
for example the position shown in figure 1 by using very different pushing means.
One thereof is for example the spindle mechanism 4, 4' with hinge points 5, 5' relative
to the frame 1 respectively 1'.
[0026] A flat support 6, respectively 6' is provided onto each bending table, onto which
support the net lies and can be displaced over. One cross bar from such a net is shown
in Figures 1 and 4 and has been given the reference 7, 7'. The longitudinal bars,
only some of which are shown, are referred to by the reference 8 (in Figure 4 - 8,
8', 8'').
[0027] At each cross bar 7, 7' means are now provided to bend this cross bar pertaining
to a net according to the four point principle described hereinabove. This occurs
without adjustment of pressure pieces. Indeed each of the cross bars are bent according
to the principle illustrated in Figures 2 and 3, independent of their diameter.
[0028] Figure 3 shows indeed schematically a non movable component referred to by the reference
9. Pressure pieces connected thereto have the references 10, 11 and 10', 11'. The
movable component accomplishing the same function as the bending table described hereinabove
is schematically shown in these Figures and referred to by the reference 12. Pressure
pieces cooperating therewith have the reference 10' and 11'.
[0029] When the movable component 12 is going to displace now to take in i.a. the position
which appears from Figure 3, the bar 13 curves to be bent finally according to an
angle resulting from the adjustment and the change of the distance and the angle separating
the non-movable component 9 from the movable component 12. When 11 and 11' are non-movable
pressure pieces and/or 10 and 10' are pressure pieces which are on the contrary movable
relative to the bar, it is clear that nets having bars which may be of different diameters
can be clamped and bent without having to use exchangeable pressure pieces.
[0030] By applying this principle to the device, more details of which are shown in figure
1 only by way of example, a net finished in advance can therefore each time be bent
according to the required angle.
[0031] To be able to achieve this with technically reliable means, said pressure pieces
consist of movable pushing cams 14, 14' and clamping means acting as hooks 15, 15'.
For each bending table, these two components form the two first points from the series
of four required for bending a bar according to the principle already described in
detail hereinabove. Each bending table further comprises pressure pieces acting as
clamping means and formed by hooks 16, 16' and pushing means acting as pressure pieces
consisting of wedge-shaped blocking means 17, 17' come each time again.
[0032] The wedge-shaped blocking means 17, 17' can be activated in any way just like the
pushing cams 14, 14', either by a spindle mechanism, or by a hydraulic or pneumatic
pistons. The wedge-shaped blocking means 17, 17' are displaced along obliquely disposed
sliding plates 18, 18'. These plates are in their turn fixed onto movable slides or
linear guides 19, 19', which, as can be deduced from Figure 1, are part of the component
20, pertaining to the bending table 2. A similar movable slide 21' is situated between
component 20, 20' and 22, 22'. This component 22, 22' is connected to the hinge axis
3, 3' mentioned already hereinabove.
[0033] From the description given hereinabove of the device according to the invention it
appears that nets, the diameter of the bars of which showing different values, can
be bent in an original way by using the principle of the four point disposition clearly
described hereinabove. Changing or adjusting pressure pieces in function of the different
diameters of bars to be bent is entirely omitted. For the first time, the possibility
is therefore given to bend nets with different bar diameters in a perfect way on an
industrial scale and at a high production rate.
[0034] The invention is of course not limited to the embodiment described herein by way
of example and a lot of modifications could be applied thereto, provided they fall
within the scope of the annexed claims.
1. A device for bending in one operation a series of parallel bars of a net, consisting
of longitudinal bars and cross bars welded thereon, according to the principle of
the four point disposition meaning that use is made of two opposite bending moments,
the points of action of which displace in such a manner that no other forces occur
during the bending operation than said moments, characterised in that it consists
of bending means which are movable with respect to a frame and extend perpendicular
or substantially perpendicular with respect to the bars to be bent, with four pressure
pieces being successively mounted both on the frame and on the movable bending means,
the two inner pieces of which being situated on the one side and the two outer pieces
on the other side with respect to the longitudinal axis of the bar and some of these
pressure pieces may be movable with respect to the longitudinal axis of the bar, in
such a manner that different bar diameters can be clamped.
2. A device according to claim 1, characterised in that said bending means consist of
a bending table (2, 2') with pressure pieces connected thereto.
3. A device according to claim 2, characterised in that said bending table (2, 2') is
hingedly connected to said frame (1, 1') at the place of the hinge axis (3, 3').
4. A device according to any one of the claims 1 to 3, characterised in that it comprises
at least one, but preferably two bending benches which are movable to and away from
each other and formed by frames (1, 1') and bending tables (2, 2').
5. A device according to any one of the claims 1 to 4, characterised in that the pressure
pieces mounted on said frame consist of clamping means, which are movable or not and
formed by hooks (15, 15').
6. A device according to any one of the claims 1 to 5, characterised in that the pressure
pieces mounted on said movable bending means consist of clamping means, which are
movable or not and formed by hooks (16, 16').
7. A device according to any one of the claims 1 to 6, characterised in that the pressure
pieces mounted on said frame consist of pushing cams (14, 14'), which are movable
or not.
8. A device according to any one of the claims 1 to 7, characterised in that the pressure
pieces mounted on said bending table consist of wedge-shaped blocking means (17, 17').
9. A device according to any one of the claims 5 to 8, characterised in that said wedge-shaped
blocking means (17, 17') are mounted movable to and fro on sliding plates (18, 18')
mounted obliquely onto said bending table (2, 2').
10. A device according to claim 9, characterised in that said sliding plates (18, 18')
are mounted in their turn on a slide (19, 19'), which can be displaced parallel to
the bar to be bent and which is itself connected via an angle profile (20, 20') to
a movable slide (21, 21') filed in its turn on the hinged component (22).
11. A device according to any one of the claims 2 to 10, characterised in that said component
(22) is displaced by means of a push arm (23) which is hingedly mounted on said frame
(1, 1').