Improved apparatus for applying filamentary material on substrate

Abstract

The invention relates to an apparatus (100) configured to apply a wire made of an electrically conductive material on a substrate, the apparatus (100) comprising means (66) for supporting the wire and guiding its deposition according to a preferably high-frequency and high-precision sinusoidal pattern, and a movable application unit (70) configured to maintain its own distance from the substrate constant during application, preferably obtained by combined heating of current conduction and current passing over the wire itself.

Description

Technical Field

[0001] The invention relates to a device for producing composite materials, in particular with a glassy matrix, for temperature control applications.

[0002] More in detail, the invention relates to a device configured for implementing laminated glass panels, in particular in the automotive field, which have integrated in their interior filaments made of electrically conductive material. Background Art

[0003] In applications where the temperature-humidity properties of the environment need to be controlled, such as in the construction and automotive fields, the use of composite materials having in particular a vitreous matrix is ​​known.

[0004] As regards the automotive sector, it is known to implement crystals of conveying devices in laminated glass in order to provide them with their own heating system which eases the visual task of the passengers by reducing condensation phenomena in the passenger compartment.

[0005] The crystals are structurally provided to include one or more intermediate layers of polymer material between two or more layers of glassy material. A lattice of filaments made of conductive material (almost invisible to the naked eye and traversed by the electric current) is "submerged" in one of these polymer layers.

[0006] In more detail, the conductive material is deposited onto the polymer layer by a dedicated application device which arranges the conductive material by following a specific orientation (usually according to a predetermined waveform) to minimize the phenomenon of undesired optical distortions. An application example is disclosed in document DE 10 2010 014 425 A1.

[0007] However, a need is felt to improve said application devices, which have drawbacks in controlling the regulation of the deposition parameters of the wires, thereby compromising the quality of the finished product.

[0008] In particular, known application devices have difficulties in applying filaments with waveforms that are "synchronous" with each other (ie filaments that, once deposited, have a substantially parallel arrangement along the main direction of deposition and the ridges and valleys of the waveforms are in phase with each other). This arrangement has the advantage of being able to apply greater currents that guarantee performance even on glasses with several layers, such as those used in the aeronautical, aerospace, naval sectors, in the armored glass and train sectors.

[0009] Currently, these "synchronous" applications are essentially based on two operating principles: the fact that an application unit is provided so as to immerse the wire in the (polymer) substrate, which application unit is consistent with the element guiding the deposition of the wire itself; and the fact that the movement of said guiding element is provided by a mechanical actuation of the piston rod-crank type, in which the motor has a single direction of rotation.

[0010] Furthermore, usually, the above-mentioned elements guiding the deposition of the wire are substantially constrained to abut at a constant distance relative to the surface of the polymer substrate, allowing variations of the order of magnitude of the semi-diameter of the wire applied (usually comprised between 15 and 30 microns) to obtain a correct application. Therefore, usually such application is carried out on a workbench of limited dimensions (for example a platform) by supporting the polymer with a glass plate in order to guarantee high planarity criteria.

[0011] The disadvantages and limitations of the known solutions are therefore multiple and are related to the overall complexity of the adjustment of the guide elements for the deposition of the guide wire, since the wire must be applied with a predetermined accuracy, distance, planarity and orientation and therefore the wire is usually moved at a low application speed (usually not higher than 25 mm per second).

[0012] It is also not possible to modify the waveform of the filament applied to the substrate, except for setting interventions of the piston-rod-crank actuation group, which cannot be performed during application but only when the machine is stationary and in a configuration phase preceding a working cycle.

[0013] Another disadvantage of the known device is that, due to the use of a platform of small dimensions, the polymer layer needs to be repositioned on the table during application. Furthermore, even if a glass support is used to improve the planarity of the polymer substrate, it is not possible to use a vacuum plane to ensure perfect stretching of the polymer substrate on the table, since said substrate may be wrinkled, with the risk of errors during the application of the wire. Summary of the invention

[0014] Therefore, the technical problem proposed and solved by the present invention is to overcome the above-mentioned problems, which is achieved by a device configured to apply a conductor on a substrate as defined in claim 1.

[0015] In particular, it is an object of the present invention to provide an apparatus configured to apply a conductive line on a substrate, which apparatus allows for on-the-fly modification of conductive line application parameters, such as length and width of the waveform and deposition path, during application.

[0016] Another object of the present invention is to provide an apparatus configured to apply a wire on a substrate, wherein the application is adaptive relative to the operating conditions and wherein the motion to produce the filament waveform results from the actuation of a kinematic chain independent of the one providing the crank mechanism.

[0017] An object of the present invention is also to provide a device configured to apply a conductor on a substrate which allows acting on a work support having large dimensions and a vacuum plane by avoiding repositioning of the polymer substrate and by reducing the risk of wrinkles appearing on the polymer substrate.

[0018] Another object of the present invention is to provide an apparatus configured to apply a conductor line on a substrate, which apparatus acts with high precision and rapidity, in particular at an application speed that can reach 450 millimeters per second.

[0019] It is also an object of the present invention to provide an apparatus for applying conductive lines on a substrate which provides a high-quality finished product.

[0020] Additional features of the invention are defined in the corresponding dependent claims.

[0021] The present invention relates to a device configured to apply a wire made of a conductive material on a substrate. The device comprises a guide device for supporting the wire and guiding the deposition on the substrate and an application unit placed at the guide device. The application unit can move between a first state raised relative to the substrate and a second contact state in contact with the wire and the substrate.

[0022] The application unit and the guide means are actuated by motor means configured to allow the guide means to rotate between two predetermined angular positions relative to a translation axis of the application unit orthogonal to the substrate.

[0023] It will be understood that this solution allows overcoming the reduced flexibility of application of known solutions, in which the guide system is generally associated with a piston-rod-crank mechanism so as to obtain the movements required for the deposition of the wire according to a pre-established pattern, and in particular includes "reversals" - or oscillations - of the movement of the guide means between the aforementioned predetermined angular positions allowing the realization of a waveform with peaks and valleys.

[0024] Advantageously, by simplifying the actuation and by improving the dynamics of the implementation chain to apply the wire on the substrate faster (at about 100 reversals per second) and precisely, the motor means of the device of the invention comprise an electric motor having two main functional elements, namely a stator element and a rotor element integral with the guide means. Thus, the application unit of the device can receive the wire from the guide means at the desired position and, in contact condition, it can press the wire into the substrate.

[0025] Advantageously, the device comprises heating means and the application unit is made of metal to allow the wire to be applied in the support (polymer) by softening the wire using two synergistic techniques: heating the substrate and the wire by contact heat transfer, in combination with or instead of heating the wire by passing an electric current, since the application unit can be heated at a temperature higher than that of the substrate.

[0026] It will be appreciated that such a solution advantageously allows obtaining a device that guarantees high flexibility in applying the conductive lines on the substrate while maintaining very high precision during deposition.

[0027] According to another advantageous aspect of the invention, the device can include a deformation or dragging device comprising at least one pair of wheels carrying a plurality of wire deformation elements on the circumference. In particular, the plurality of deformation elements are configured to come into contact with the wire in the engagement area and then deform the wire. Thus, in the case of a need to compare possible residual tension inside the wire, the wire can not only be guided but can even be plastically deformed according to a predetermined waveform during application.

[0028] Other advantages together with the features and modes of use of the invention will be apparent from the following detailed description of a preferred embodiment of the invention shown by way of example and not for the purpose of limitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Reference will be made to the figures reported in the accompanying drawings, in which:

[0030] - Figure 1 shows an overall perspective view of a device configured to apply a wire made of a conductive material on a substrate according to a preferred embodiment of the present invention;

[0031] - Figure 2 Shows Figure 1 A part of the device shown, in particular relating to the guiding device and the application unit;

[0032] - Figure 3 Shown with Figure 2 A section of a preferred embodiment of the guide device for the wire and the application unit shown;

[0033] - Figure 4 Shows Figure 1 An overall stereoscopic view of the device shown, which can be optionally provided with a wire deformation device. DETAILED DESCRIPTION

[0034] The present invention will be described below with reference to the above-mentioned drawings.

[0035] First refer to Figure 1 and Figure 2 , shows a preferred embodiment of an apparatus for applying wires made of an electrically conductive material, which is indicated as a whole by the reference numeral 100. The apparatus is intended for use in production processes involving the implementation of composite materials, preferably in stations for the implementation of components for the automotive, aeronautical, naval, railway industries, in particular for the implementation of glass formed by a sandwich structure comprising vitreous and plastic materials.

[0036] More preferably, the device to which the invention relates can be applied to the implementation of a windshield made of laminated glass or composite glass, in which an intermediate layer of plastic material (for example polyvinyl butyral (PVB)) is interposed between one or more layers (or films) of vitreous material and which is suitable for receiving a wire made of an electrically conductive material, which remains "submerged" therebetween.

[0037] The wire not shown in the figures and suitable for being applied by the device 100 is preferably a wire made of tungsten and allows electrically heating the glass to maintain good visibility even in adverse weather conditions such as ice or condensation formation.

[0038] The physical properties and dimensional characteristics of such wires are well within the scope of those skilled in the art and will not be described in further detail below.

[0039] The device 100 according to the invention may also allow the realization of products featuring properties similar to those just mentioned but intended for different uses, for example glass in the construction field or for building projects.

[0040] The apparatus 100 is preferably configured to cooperate with a device, not shown in the drawings, under operating conditions, which receives a substrate on which the conductor is deposited. As mentioned, the substrate is preferably made of plastic material and can be received on the surface of a workbench, preferably a platform (delineator), for omnidirectional application of the conductor.

[0041] According to a preferred operating mode of the device 100, the conductive wire is applied on the substrate according to a main direction of longitudinal deposition and in a manner forming a pattern or figure consisting of filaments spaced apart and oriented parallel to each other. Each filament has a wave shape in which the peaks and valleys are preferably "in phase" with each other.

[0042] It will be appreciated that the present invention advantageously allows for precise parallel application of filamentary materials and "in-phase" of waveforms, as will be described in greater detail below.

[0043] In general, the device 100 is provided with a wire feed device which can be configured to even adjust the application speed. The feed device comprises control elements, for example sensors, such as tension control devices indicated as a whole by reference numerals 11, 14 and 15. Such control elements allow the speed for unwinding the wire to be adjusted, for example according to the movement of a table receiving the substrate or for tensioning a predetermined parameter of the wire which it is desired to set / maintain during application.

[0044] The wire may be supported by one or more coils 12A and 12B on which the wire is wound, or may even be remotely located relative to the device 100. In embodiments, wire unwinding may be assisted by an unwinding device, such as a motorized coil 13.

[0045] The device 100 also comprises means for supporting the wire and guiding its deposition on the substrate according to said predetermined and preferably high frequency sinusoidal pattern, and a movable application unit configured to keep itself at a constant distance from the substrate during application. Such application is preferably achieved by combined heating by current conduction and passage of current on the wire itself, as will be described in detail below.

[0046] By further reference Figure 3 , the application unit, generally indicated by reference numeral 70, is placed at the guide means, generally indicated by reference numeral 66, and is movable between a first state elevated relative to the substrate and a second state in contact with the conductor and the substrate. The figure shows the application unit in an elevated state relative to the substrate.

[0047] The motor means of the device 100 allow the application unit 70 to be translated along an axis A which is orthogonal to the substrate when the device 100 is in use. In particular, the application cylinder 50 (eg a low-friction pneumatic cylinder) allows the application unit 70 to be raised or lowered relative to the substrate.

[0048] The control unit of the device 100 is configured to control the motor means, the guide means 66 and the application unit 70. Advantageously, the device 100 allows adjusting the application pressure of the wire on the substrate by the application unit 70 by means of the control unit and the application cylinder 50.

[0049] The guide device 66 of the wire is rotationally movable between two predetermined angular positions about said translation axis A of the application unit 70. In other words, the guide device oscillates between two predetermined angular positions.

[0050] In a preferred embodiment, the motor arrangement comprises an electric motor provided with a stator element 40 and a rotor element 41 integral with said guide arrangement 66 .

[0051] Advantageously, therefore, two predetermined angular positions can be obtained depending on the rotation frequency of the rotor element 41 .

[0052] The guide means 66 of the wire, i.e., support the wire and they have the purpose of positioning the wire in the requested position for subsequent application of the wire in the substrate by means of the application unit 70. The frequency associated with the rotation of the rotor element 41 can reach 50 Hz or an equivalent frequency, so as to obtain even 100 reversals or oscillations per second (i.e. to reach two predetermined angular positions). As described, the control unit of the device 100 controls the correct actuation of the guide means 66 according to the project specifications. This actuation can be set by a software interface (Ewibe).

[0053] As can be seen in the figure, the guide device 66 is preferably interposed between the motor device, in particular the rotor element 41, and the application unit 70. In the embodiment shown, the guide device comprises a hollow housing 66', preferably shaped as a cylindrical element, which has end openings 67a, 67b and is arranged coaxially with the rotor element 41.

[0054] Said hollow casing 66' is configured to house internally an application unit 70. An annular air gap remains defined between the inner surface of the hollow casing 66' and the application unit 70 in order to ensure the translation of the latter.

[0055] In particular, the application unit preferably includes a metal body 70' that is slidably movable within the hollow housing 66'. In the contact condition of the application unit 70, the terminal portion T of the metal body 70' passes through the opening 67a of the hollow housing 66' facing the substrate. As described above, by adjusting the sliding of the application unit 70, possible height differences existing in the substrate can be automatically compensated by raising or lowering the application unit 70 so that it constantly maintains contact with the wire and the substrate during the above-mentioned contact condition.

[0056] The hollow housing 66' is coupled to the rotor element 41 and rotates integrally therewith. Preferably, a support element for the wire, such as a wire hoop 69, protrudes from the end of the hollow housing 66' at the opening 67a facing the substrate. Such a wire hoop 69 is integral with the movement of the hollow housing 66' and it is preferably realized in the form of an eyelet through which the wire to be deposited passes.

[0057] The wire supported by the wire clamp 69 performs a swinging movement of the wire clamp 69 between two predetermined angular positions and is positioned according to a desired waveform to be subsequently pressed against the substrate by the terminal portion T of the application unit 70. The application unit 70 is located below the wire clamp 69 with respect to the direction in which the wire is fed into the device 100.

[0058] Preferably, the device 100 also comprises heating means for the application unit 70 and / or the wire. The heating means comprises a resistor 68 carried by the application unit and energizable support means for the wire.

[0059] In particular, the heating means allow heat to be transferred to the wire by conduction, i.e. heating the metal body 70' through the resistor 68 and then heating the terminal portion T on which the wire slides during the contact condition. The heating means also preferably allow an electric current to circulate in the wire by applying a potential difference, for example of the order of a few volts, in the wire bundle comprised between the terminal portion T of the metal body 70' and said energizable support means, shown in the figure as a wheel 30 on which are wound the spring 31 and the wire fed by the contact 32.

[0060] The heating of the wire provided in conjunction with the above-described system allows the device 100 to apply the wire at higher speeds (e.g. up to 450 millimeters per second (mm / sec)) and at lower temperatures, below 200° C. and preferably including about 100° C., relative to known solutions, by reducing in particular stress phenomena on the substrate, since, as described, the substrate is preferably made of a plastic material that does not like to receive applied filamentary material at high temperatures.

[0061] Advantageously, however, the control unit is configured to allow adjustment of operating parameters of the heating device programmed by an operator using the control panel, such as adjustment of the temperature of the application unit 70 via the resistor 68 and adjustment of the applied potential difference.

[0062] Preferably, the device 100 comprises a cutting unit 71 configured to cut the wire once the application is finished and to restart the subsequent application. In the example shown, the cutting unit 71 comprises a locking-or punching-member to lock the supply of wire and appropriate cutting members. The cutting unit 71 is preferably positioned downstream of the heating device, in particular downstream of the application unit 70 with respect to the direction in which the wire is fed into the device.

[0063] Now refer to Figure 4 , shows an alternative schematic embodiment of the device 100, which comprises a deformation or dragging device, which is generally indicated by the reference numeral 20 and includes a pair of wheels 21, 22, which carry a plurality of deformation elements 23 of the wire on the circumference.

[0064] The plurality of deformation elements 23 are configured to come into contact with the wire in the bonding region M and deform the wire.

[0065] The device 100 essentially allows maintaining the alignment and stretching of the wire until it reaches the pair of wheels 21 , 22 , enabling the deformation elements carried by them to deform the wire before it is deposited—according to a predetermined waveform—on the substrate.

[0066] In fact, the wires applied to the substrate can generate tension inside the glass, which can cause optical distortions. The wires can then be deformed preferably according to a sine (or cosine) waveform and subsequently guided by the guide device 69 during application according to the desired waveform, so that no residual tension occurs in the final product.

[0067] As described, the deformation device 20 comprises at least one pair of wheels 21, 22. They support a deformation element 23, which is realized, for example, as a pin or tooth shape, which can extend in the annular surface on the wheels 21, 22 or even be formed in an annular area extending from the annular surface on the wheels in the axial direction.

[0068] According to a preferred embodiment of the invention, the deformation element 23 of the first wheel 21 occupies the free space between the deformation elements of the second wheel 22 of the at least one pair of wheels by rotating, in fact by achieving a kind of "contactless" engagement between the two wheels in the engagement area M. The first wheel 21 and the second wheel 22 have opposite directions of rotation, preferably with the respective axes of rotation being parallel between them.

[0069] Furthermore, the deformation device 20 is connected via a control unit to the aforementioned device for feeding and regulating the application speed 11 of the wire. The device 100 is configured to deform the wire preferably according to its tension, its advancement speed or application speed, the latter being parameterized, for example, according to the device receiving the substrate.

[0070] During application, the deformation of the wire is preferably greater than the deformation that occurs once it is applied on the substrate. In this sense, the device 100 applies a slight tension, since advantageously it tends to keep the wire passing through the guide means, in particular through the wire hoop 69, and relative to the predetermined application position on the substrate. This tensioning is obtained by adjusting one or more control parameters implemented by the control unit, which, by controlling the rotation speed of the pair of wheels 21, 22, allows the wire to come out of the joining area M at a slower advancement speed than the speed at which it is applied on the substrate.

[0071] The present invention has been described in detail with reference to the preferred embodiments of the present invention. This means that each technical solution implemented in the preferred embodiments (described here by way of example) can be advantageously combined with other embodiments and described differently to produce other embodiments belonging to the same inventive core but all within the scope of protection of the attached claims.

Claims

1. A device (100) configured to apply a conductive line made of a conductive material on a substrate, the device (100) comprising: a guiding device (66) for supporting the wire and guiding the deposition on the substrate, an application unit (70) placed at the guide device (66) and movable along a translation axis (A) orthogonal to the substrate between a first state raised relative to the substrate and a second state in contact with the wire and the substrate, motor means (40, 41, 50) configured to allow rotation of the guide means (66) and translation of the application unit (70) along the translation axis (A), The guide device (66) is rotatable about the translation axis (A) of the application unit (70) between two predetermined angular positions.

2. The device (100) according to claim 1, wherein The motor device comprises an electric motor provided with a stator element (40) and a rotor element (41), the rotor element (41) being integral with the guide device (66).

3. The device (100) according to claim 1 or 2, wherein: The two predetermined angular positions are obtained as a function of the rotation frequency of the rotor element (41).

4. The device (100) according to claim 2 or 3, wherein: The guide device (66) is interposed between the motor device (40, 41) and the application unit (70) and comprises a hollow housing (66') which is coaxial with the rotor element (41) and is shaped to accommodate the application unit (70) inside.

5. The device (100) according to the preceding claim, wherein: The guide device comprises a support element (69) for the wire which is integral with the hollow housing (66'), the support element (69) protruding outward from the hollow housing (66') and facing the substrate.

6. The device (100) according to any one of the preceding claims, wherein: The applying unit (70) comprises a metal body (70') which is slidably movable inside the hollow shell (66'), wherein when the applying unit (70) is in the second contact state, the metal body (70') passes through an opening (67a) of the shell (66') facing the substrate.

7. The device (100) according to any of the preceding claims, further comprising an application unit (70) and / or a heating device (30, 31, 68) for the wire.

8. The device (100) according to the preceding claim, wherein The heating device comprises a resistor (68) carried by the application unit (70) and an energizable support device (30, 31) for the conductor.

9. The device (100) according to any of the preceding claims, further comprising a deformation device (20) for the conductor, which is arranged upstream of the guide device (66) with respect to the direction in which the conductor is fed into the device (100).

10. The device (100) according to the preceding claim, wherein The deformation device comprises a pair of wheels (21, 22) which circumferentially carry a plurality of deformation elements (23) of the wire.

Images