U.S. patent application number 12/303194 was filed with the patent office on 2009-08-20 for device for laying down a thin metal wire on a surface.
This patent application is currently assigned to SAINT-GOBAIN GLASS FRANCE. Invention is credited to Benno Dunkmann, Michael Labrot.
Application Number | 20090206191 12/303194 |
Document ID | / |
Family ID | 38474446 |
Filed Date | 2009-08-20 |
United States Patent
Application |
20090206191 |
Kind Code |
A1 |
Dunkmann; Benno ; et
al. |
August 20, 2009 |
DEVICE FOR LAYING DOWN A THIN METAL WIRE ON A SURFACE
Abstract
A device for laying a thin metal wire taken from a coil of wire
stock onto a surface, in particular onto the surface of a sheet,
using a presser. The device includes a mechanism exerting
mechanical tension in a region of the wire that lies between the
rotary coil of wire stock and the presser, and a wire-guiding
device provided in the region. The wire-guiding device includes a
tensioning device that acts directly on the wire taken off the coil
of wire stock. That makes it possible effectively and appreciably
to compensate for changes in relative speeds at which the wire and
the sheet progress.
Inventors: |
Dunkmann; Benno; (Liege,
BE) ; Labrot; Michael; (Aachen, DE) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
SAINT-GOBAIN GLASS FRANCE
Courbevoie
FR
|
Family ID: |
38474446 |
Appl. No.: |
12/303194 |
Filed: |
May 30, 2007 |
PCT Filed: |
May 30, 2007 |
PCT NO: |
PCT/FR2007/051350 |
371 Date: |
December 2, 2008 |
Current U.S.
Class: |
242/417 ;
242/416; 242/421 |
Current CPC
Class: |
H05B 3/86 20130101; H05B
2203/017 20130101 |
Class at
Publication: |
242/417 ;
242/416; 242/421 |
International
Class: |
B65H 59/24 20060101
B65H059/24; B65H 59/22 20060101 B65H059/22; B65H 59/10 20060101
B65H059/10; B65H 59/04 20060101 B65H059/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 2, 2006 |
DE |
102006025893.2 |
Claims
1-14. (canceled)
15. A device for laying onto a surface a thin metal wire taken from
a coil of wire stock, using a presser, the device comprising: means
for exerting mechanical tension in a region of the wire that lies
between the coil of wire stock and the presser, a wire-guiding
device provided in the region, and wherein the wire-guiding device
comprises a tensioning device that acts directly on the wire taken
off the coil of wire stock.
16. The device as claimed in claim 15, wherein the wire is guided
in the region of the tensioning device over a portion of variable
length.
17. The device as claimed in claim 16, wherein the variable length
of the portion can be defined using at least one mobile tensioning
roll or a sliding part that has an equivalent function.
18. The device as claimed in claim 15, wherein the wire is guided
through the tensioning device by, in turn, a first turn roll, a
mobile tensioning roll, and another turn roll, or by corresponding
sliding parts.
19. The device as claimed in claim 15, wherein the tensioning
device comprises a tensioning roll or a sliding part that has an
equivalent function and that is mounted on an elastically urged
pivoting lever.
20. The device as claimed in claim 15, wherein the wire is guided
through the tensioning device by a mobile and/or curved sliding
rail.
21. The device as claimed in claim 17, wherein the tensioning roll
or the sliding part that has an equivalent function are mounted in
a sliding guide.
22. The device as claimed in claim 15, wherein the tensioning
device comprises at least one spring and/or a drive mechanism that
is feedback controlled.
23. The device as claimed in claim 15, wherein the tensioning
device comprises a device for measuring the tension in the wire at
any moment.
24. The device as claimed in claim 15, further comprising a brake,
braking force of which is feedback controlled, so as to damp
rotational movement of the coil of wire stock.
25. The device as claimed in claim 15, further comprising means for
mechanically corrugating the wire between the tensioning device and
the pusher.
26. The device as claimed in claim 15, comprising plural laying
devices.
27. The device as claimed in claim 15, wherein the surface that is
to have the wire laid thereon is a sheet fixed to a flat or curved
laying surface, and the wire is laid down by relative movement of
the pusher and/or of the sheet, one relative to the other.
28. The device as claimed in claim 15, wherein a support element
for supporting the sheet can be moved reversibly with respect to
the pusher.
Description
[0001] The invention relates to a device for laying down a thin
metal wire onto a surface and in particular onto the surface of a
sheet, which has the features of the preamble of claim 1. It
relates in particular to the preparation of sheets for wire-heated
laminated window panes.
[0002] Wire-heated laminated window panes are to be understood in
particular as meaning panes for windows and the like which have a
multilayer structure consisting of at least one rigid pane (made of
glass or of a synthetic material) and of one layer or sheet of a
synthetic material bonded to its surface, several resistive wires
laid down by a machine being positioned in the surface that forms
the boundary between the rigid pane and the layer or sheet of
synthetic material. These wires are generally electrically
connected in parallel and are powered with heating voltage using at
least two collectors. The collectors generally extend along each
exterior edge of the pane. In general, the sheets equipped with
wires are sandwiched between two rigid panes.
[0003] European patent EP 0 443 691 describes a device of this
type, for laying these wires down onto sheets. It comprises a
mobile laying device to which the wires taken from a coil are led
via an eyelet guide and two toothed wheels meshing with one
another. Document DE 20 43 746 describes such a wire-laying device
which has a wire-guiding tube positioned between the coil of wire
stock and the laying location.
[0004] Document DE 41 01 984 A1 describes a similar device which
has a simple guide between the coil of wire stock and the toothed
wheels. Reduction gearing is provided between the toothed wheels
and the constantly driven roll which pushes the wires onto the
sheet. The toothed wheels turn slightly more slowly than the
presser roll. It is thus contrived for the corrugated wire to
remain always under a slight tensile load in its path between the
toothed wheels and the presser roll. Uncontrolled movement of the
laid-down wire is thus avoided.
[0005] In document DE 42 01 620 A1, for such a device designed to
lay wires in straight lines, and which therefore does not have a
wire-corrugating means, an electrical brake is provided on the coil
of wire stock. This brake is designed to maintain constant tension
in the wire paid out. In their path between the coil and the
presser roll, the wires pass over deflection and guide rollers
which have no braking function and are mounted on ball
bearings.
[0006] Customarily, the sheets that are to be provided with the
wires in these known devices are fixed on rotary drums which allow
the substrate in sheet form to advance more or less continuously
beneath the wire-laying devices. Depending on the local curvature
intended for the wires, the rotational movement of the drum may
also be set to different speeds so that braking or acceleration
transitions are achieved.
[0007] When a device such as this is provided with a braking system
and with mechanisms for corrugating the wire that is to be laid
down, oscillations which arise out of the deformation of the wire
and out of the relative inertia of the coil of wire stock interact
and therefore cause uneven corrugations to be formed.
[0008] Furthermore, the ratio between the rotational speed of the
coil of wire stock and the rotational speed of the drum to which
the sheet of PVB that is to be equipped with the wires is fixed is
not constant. What this means is that the tensile force with which
the wire is taken off the coil is not constant. There is therefore
a need to keep the tension in the wire constant.
[0009] The problem underlying the invention is therefore, for a
device of the kind indicated at the start, to further improve the
guidance of the wire before it is laid onto the sheet.
[0010] According to the invention, this problem is solved by the
features of claim 1. The features of the dependent claims provide
advantageous developments of the invention.
[0011] By inserting a tensioning device or tensioning element in
the path of the wire between the coil of wire stock which may or
may not be braked, the desired improvement can be achieved. The
tensioning element ensures constant tension in the wire prior to
the laying operation proper and possibly prior to its corrugation.
The influence of relatively slow rotation of the coil of wire
stock, particularly when the coil is full, on the subsequent
corrugating and laying of the wire is thus greatly reduced.
[0012] In other words, the wire is passed through a "buffer region"
(for example one provided with turn rollers) in order thus to
compensate for the change in tensile force at the exit of the
buffer region through a suitable compensation of the force and a
compensation of the length of the wire within the buffer
region.
[0013] This solution according to the invention has not hitherto
been proposed in the state of the art because, fundamentally, with
the known electrical brake, the problem of oscillations of the wire
could be considered to have been resolved. The solution according
to the document DE 20 43 746 mentioned above, which consists in
passing the wire through a tube, gives no indication in this
respect. The document does not disclose that it anticipates this
guide tube exerting a braking function. On the contrary, in that
document it is assumed that the wire slides through this tube with
little friction.
[0014] Concrete options for evening out the tension in the wire in
the compensation portion concerned comprise passive compensation
using mechanisms actuated by gravity and active compensation by
means of elastic elements, pneumatic actuators or regulating
motors.
[0015] A wire-laying device thus equipped is as suitable for laying
wires uniformly, in the conventional manner, with or without
corrugation, in even paths as it is for laying the wire in the
recently proposed paths involving all kinds of curves, divergent
paths, non-circular paths of variable radius, with local increases
and/or reductions in the wire-laying density, etc. The tensioning
device according to the invention displays its advantages
particularly in the last-mentioned laying formats because in these
instances it is often necessary to operate the sheet support at
variable speeds. It is even possible (in a way known per se) that
the direction of travel may need to be reversed.
[0016] Other details and advantages of the subject matter of the
invention will emerge from the drawing of one exemplary embodiment
of a wire-laying device according to the present invention and of
its description given hereinafter.
[0017] In simplified depictions which are not drawn to scale:
[0018] FIG. 1 depicts an overall view of the device according to
the invention, with a sheet substrate securing drum and a single
wire-laying device, and
[0019] FIG. 2 depicts a view of a device for compensating for the
tension in the wire.
[0020] The device according to the invention depicted in FIG. 1
comprises a drum 1 which, thanks to a drive mechanism 2, forms a
mobile resting surface for thermo-plastic sheets (particularly
sheets made of polyvinyl butyral). The sheets 3 provided with wires
are generally set between two rigid glass and/or synthetic panes
and connect the latter through adhesion over their entire surface,
thus yielding a laminated glazing unit that can be heated using the
wires.
[0021] The cylindrical drum 1 advantageously has a large diameter
and a large circumference, so that several sheets 3 can be set on
its cylindrical wall. Here, we can see two sheets 3 of the same
size. They are fixed to the envelope surface of the drum,
preferably by suction or pressure difference. To these ends, the
envelope surface is equipped in the known way with a great many
bores through which air is sucked. Atmospheric pressure presses the
sheets onto the envelope surface.
[0022] Positioned above the drum 1 is a wire-laying device 4 (also
known as a laying head). By virtue of a drive mechanism that has
not been depicted in detail, this device can be moved back and
forth parallel to the axis of rotation of the drum (and therefore
parallel to the direction in which the figure is viewed) along a
straight guide 5. A wire 7 is taken off a coil 6 of wire stock and
ultimately laid using a presser roll 8 (preferably one that can be
heated) onto the sheet 3 or incorporated into the surface
thereof.
[0023] FIG. 1 shows that the wire is laid down continuously in
successive loops, even onto the edges of the sheet 3. It is obvious
that these loops need to be cut off once the wire has been laid and
before the sheet 3 is removed from the drum 1. It is also obvious
that it is possible to use several wire-laying devices, situated
one beside the next and synchronized, on one drum 1.
[0024] The coil 6 of wire stock may, in the known way, be equipped
with an adjustable brake, for example an electric brake. The
presser roll 8 is preferably elastically preloaded against the
envelope surface of the drum 1 and runs along the sheet 3 without
its own drive mechanism.
[0025] In the path between the coil 6 of wire stock and the presser
roll 8, the wire 7 passes through a guide device denoted in its
entirety by 9 in FIG. 1. This is used, on the one hand, and in the
known way, to confer a zigzag or corrugated pattern upon the wire
passing through it. It is known that laying the wires 7 in a zigzag
minimizes their visibility in the finished laminated glazing unit
(on this aspect, reference can be made to the literature mentioned
at the start).
[0026] In addition, the guide device 9 presents the wire 7 passing
through it with another tensioning device more details of which are
given in FIG. 2.
[0027] For simplicity, this FIG. 2 depicts the entire guide device
9 and the path of the wire 7 between the coil 6 of wire stock and
the presser roll 8 in the same plane because it is intended merely
to explain how the invention works rather than depicting a concrete
embodiment thereof.
[0028] Like FIG. 1, FIG. 2 shows a portion of a sheet 3 placed on
the drum and the wire 7 which is paid out from the coil 6 of wire
stock (damped by the brake 6B known per se) and which is conveyed
to the presser roll 8 by the guide device 9, as indicated by
several arrows in the path of the wire. On both sides of the
presser roll 9 the arrows show the instantaneous direction of
travel of the envelope surface of the drum and of the sheet 3. When
the presser roll and the entire wire-laying device are designed
accordingly, the direction of rotation of the drum can also be
reversed in order to lay wires in more complicated paths and/or
when the drum is stationary, a wire can also be laid simply by
shifting the wire-laying device sideways.
[0029] Some lines of wire 7' have already been laid onto the sheet
3 in earlier rotations of the drum 1 and the presser roll 8 has
therefore to be situated in such a way as to be able to lay another
line of wire 7' to their right. In an embodiment known per se, the
presser roll 8 has a planar and domed presser surface. The wire 7
passes over the line of its crown. In this way, the wire 7 is
pushed into the surface of the sheet 3 without the lateral edges of
the presser roll 8 penetrating the sheet 3.
[0030] The guide device 9 comprises, in the way known per se, two
toothed wheels 10 which mesh in one another and which give the wire
7 guided between them the desired corrugation immediately upstream
of the presser roll 8. In order to simplify matters, the
corrugation of the wires laid onto the sheet 3 has not been
depicted. As far as the relative speeds of the toothed wheels and
of the presser roll are concerned, reference can be made to the
prior art described above.
[0031] According to the invention, on leaving the coil 6 of wire
stock and before infiltrating between the toothed wheels 10, the
wire 7 passes through a tensioning device denoted in its entirety
by 11. In its exemplary embodiment depicted here, this tensioning
device comprises two fixed guide rolls 12 and, between these, a
mobile and elastically preloaded tensioning roll 13. The latter
roll is mounted to rotate in the tensioning device 11 and/or in the
guide device 9 on an oscillating or pivoting lever 14 which is
itself preloaded by means of a pressure spring 15. A broken line
has been used to represent various possible positions of deployment
of the pivoting lever 14 away from the central position depicted in
solid line.
[0032] The guide rollers and the tensioning roller may also just as
easily be replaced by sliding guides if the wire is able to slide
over these with negligible friction. These are not therefore
excluded, even though the text which follows refers always to
rolls.
[0033] On the whole, the invention makes it possible to obtain a
reaction that is as sensitive and immediate as possible of the
tensioning device 11 to variations in the instantaneous tension of
the wire. A particularly low mass of the moving parts of the
tensioning device and low friction in all the mountings and
anywhere that sliding might occur make a particularly strong
contribution to this aspect.
[0034] It can be seen that, between the two guide rolls 10, the
wire 7 forms a U-shaped loop of which the depth with respect to the
guide rolls 12 is defined by the effective position of the moving
tensioning roll 13 which is kept under load by the spring 15. This
loop allows for fairly substantial compensation for the length,
measuring several centimeters, in that part of the wire that at any
moment lies between the coil 6 of wire stock and the presser roll
8.
[0035] If an even greater variation in length needs to be
compensated, the tensioning roller 13 (which is elastically
preloaded) can also be guided in a straight line in a readily
accessible sliding guide, against the action of an elastic force or
the like, rather than being so by the pivoting lever depicted, so
as to be able to extend over a greater length without any angular
shift.
[0036] On the whole it is possible very simply and with low inertia
to compensate for variations in the rotational speed of the drum 1
which variations cause the rotation of the presser roll 8 to
accelerate or decelerate and therefore generally also lead to
uneven wire consumption. In particular, the mass of the coil 6 of
wire stock which varies greatly according to how much wire stock
still remains, and the relative inertia of the brake 6B play no
part in this compensation, which is therefore able to react quite
sensitively.
[0037] After the guide roll 12 situated downstream with respect to
the direction of travel of the wire, the wire 7 again passes
through two guide rolls 16 which lead it exactly centrally between
the toothed wheels 10. The latter can obviously also be replaced by
the sliding guide or even be completely omitted if, after the
second guide roll 12, the wire 7 can be inserted between the
toothed wheels 10 with sufficient precision.
[0038] Obviously it is possible to use many other ways of
maintaining a defined tension in the wire, even at these points, as
long as the aforementioned conditions (and the bulkiness data and
the possibility of adjusting the tension in the wire) provide the
same effect. Thus, in concrete terms, it might be possible to
provide a sliding moving rail rather than the tensioning roll, if
it is anticipated that it will be necessary to compensate for an
excessive difference in length. These sliding rails are known in
chain drives or belt drives. They run longitudinally in a curve the
radius of curvature of which changes according to the tension in
the wire passing through them.
[0039] Furthermore, in place of the helical pushing spring 15
depicted diagrammatically here, it would also be possible to use
other means of adjusting the tensioning roll 13, for example, a
pneumatic spring, or a pneumatic, electrical or similar adjustment
drive mechanism.
[0040] The tensioning device may optionally also comprise a
measurement unit (not depicted here) which determines the actual
tension in the wire and then dictates the tensioning force needed
at any moment to an associated adjustment drive mechanism. A
measurement unit such as this might be able, for example, to detect
the force exerted on its bearing by one of the turn rollers 12,
which force increases as the drum 1 accelerates and decreases as
the drum 1 slows down. When the force on the wire is small, it
would then be necessary to provide additional tensioning, whereas
if the tensile force increased, the tension could be reduced.
* * * * *