MXPA96005396A - Procedure and device for depositing and fixing a thin metal thread on a peliculatermoplastic of a deho glass glass - Google Patents

Abstract

The present invention relates to a process for depositing and fixing a thin metallic wire on the surface of a thermoplastic film of a laminated glass, in which the thermoplastic film is maintained by a vacuum on the surface of a cylindrical drum, which is rotated and the metallic wire, with the help of a wire depositing device that incorporates a heated mounting tool, a wire supply reel and means for passing the wire from the wire supply reel under the heated mounting tool , is continuously deposited on the film as a result of a linear advance movement imparted to the wire depositing device, on a guide arranged parallel to the drum axis, characterized in that the drive for the linear advance of the wire depositing device, it is controlled according to a time-path program established according to the desired curve shape of the wires

Description

PROCEDURE AND DEVICE FOR DEPOSITING AND FIXING A THIN METAL THREAD ON A THERMOPLASTIC FILM OF A LENS GLASS CRYSTAL DESCRIPTION The invention relates to a method for depositing and fixing a thin metallic thread on the surface of the thermoplastic film of a sheet glazing, in which the thermoplastic film is maintained by depression on the surface of a cylindrical drum; the drum is rotated; the wire, with the aid of a yarn depositing device comprising a heated crimping tool, a yarn feeding spool and means for routing the yarn from the yarn feeding spool below the heated crimping tool, is deposited continuously on the film due to the fact that a linear feed movement is communicated to the yarn deposit device, on a guide arranged parallel to the axis of the drum. The invention also relates to a device intended to execute the process and to a thermoplastic film as obtained from the process. A method of this type is known from DE 1 201 620 A1. In this known method, the yarn deposition device moves parallel to the drum axis by means of a screw drive, while the drum rotates. By a regular advance of the yarn deposition device with the help of the screw drive, the helical yarn is deposited on the surface of the drum and forms on the sheet of the yarn segments extending in a rectilinear manner according to a parallel arrangement. The crimping tool is constituted in this case, by a heated press strip. An electromechanical brake is coupled to the feeding reel, to keep the wire under a certain tension. The method cited at the beginning of the present specification is also known from EP 0 443 691 A1. In this case, the yarn is deformed before the helical deposit, with two gears in contact with one another, such so that it moves on the thermoplastic film in wavy form. The known, large-scale method is used to produce sheet security glazing that can be heated electrically. In this case, collector conductors in the form of tin-plated copper foil strips are fixed on the thermoplastic film first along two opposite edges of the thermoplastic film. After the helical deposit of the wire, the wire is connected to the collector wires, due to the fact that another strip of tin-plated copper foil is deposited on the lower copper foil paper strip, and the two metal foil strips they weld with brass or tin one with another, including the threads. Then, the wires are cut to the outside of the collector conductors. Then, the film coated with yarn segments is removed from the drum and machined to incorporate it into the glazing of sheets. The encristalados of security of leaves that can warm up, use so much in the construction as in the vehicles. In most cases, particularly when dealing with rectangular glazing, the arrangement of the heating wires in a rectilinear orientation is desired, as is obtained with the aid of the method of the specified type. In the case also of glazing forms that deviate from the rectangular shape, in particular in the case of rear glazing-sides of automobiles, they can be heated; the heating wires were arranged to date, according to a rectilinear orientation. The object of the invention is to develop the method mentioned at the beginning of the present specification, in such a way as to allow the deposition of the metallic thread on the thermoplastic film according to any curved shape. The development of the method according to the invention, resides in the fact that the drive for the linear advance of the yarn deposition device is controlled according to a time-stroke program established as a function of the desired curved shape of the yarns. Therefore, the invention provides, instead of a regular advancement of the yarn deposition device in a single direction, to command the displacement of the yarn depositing device, in such a way that the advance of the yarn depositing device is made in the two directions, according to a given program, which is established on the basis of geometric data for the desired curved shape of the yarns. In this way, the feed rate of the yarn device depends, of course, on the speed of rotation of the drum. In the case of small curvatures of the thread tracings, the speed of rotation of the drum may remain constant, if the direction of the threads is substantially transverse to the longitudinal axis of the drum. With the aid of this method, for example, it is possible, in the case of automobile windshields, whose lower edge extends according to a more or less pronounced curvature, to deposit the heating wires on the film according to an arrangement parallel to that curved edge , whatever the shape of that curved edge. In an advantageous development of the invention, the method can be executed in such a way that the drive for the rotational movement of the drum is, in addition, and also controlled according to a time-stroke program established in accordance with the desired curved shape of the yarns. While, in the case of a sense of identical rotation of the drum, heating conductors can be made, for which the wires are connected in parallel by means of collector conductors, sinuous paths of the wire can be made on the film by means of a step-by-step rotation of the drum and a linear reciprocating movement of the yarn deposition device, and concentric circular paths or other paths parallel to each other of the yarn, by means of a change in the respective direction of rotation of the drum and, if necessary, a simultaneous reciprocating linear movement of the yarn deposition device. In this way, the thread can be arranged inside the sheet security glazing practically in any desired shape. According to a further advantageous aspect of the method according to the invention, it is further provided to send the angular position of the yarn deposition device about an axis of rotation perpendicular, or more or less perpendicular, to the axis of the drum in accordance with the predefined career program. Thus, the fact that no force directed transversely to the direction of the respective yarn is exerted on the yarn at the level of the deposit point is acquired, which can cause difficulties at the time of the final deposit. According to a particularly advantageous aspect, the method according to the invention is executed with the aid of a yarn deposition device for which the crimping tool is constituted by a pressing roll that rolls on the film. In this way, it is possible to use, in principle, both yarn deposit heads, by means of which a straight yarn is deposited under a curved shape, as described in EP 0 553 025 Al, as reservoir heads threads that are described in EP 0 496 669 Bl, which are suitable for depositing a corrugated thread. An appropriate device for executing the procedure, based on the single drawing, will be described below and in more detail. The invention also proposes a plastic film, especially intended to be associated with at least one rigid plate, for example made of glass, and especially bulged, to form a glazing, and comprising metal wires arranged on its surface, characterized in that the wires they are arranged according to non-rectilinear trajectories. According to a variant of the invention, the plastic film is incorporated in a glazing. According to an advantageous variant of the invention, the glazing has at least one curved edge and the metal wires are deposited along a curved path, in particular parallel to the curved edge of the glazing. Preferably, the wires are arranged in the lower area of the glazing. According to a variant of the invention, the glazing comprises an opaque curve deposited on the glass in relation to at least part of the metal wires.

The encristalados according to the invention can serve above all encristalados heaters thanks to an electrical feeding of the threads. Preferably, the glazing serves as a glazing heater in the lower area: in this way, the windshield wiper blades are prevented from sticking to the windshield in cold weather. With the aid of the device shown in the single figure, the thermoplastic films 1, 2, for example of polyvinyl butyral, should be coated in a selected area, with thin heating wires according to certain curves. The films 1, 2 are intended to produce windshields that have a more or less trapezoidal shape comprising the lateral edges 3, 4, the lower edge 5 in arc of circle and the upper edge 6 also in arc of circle. The film itself may be a little larger than what corresponds to the final shape of the windshield. The edge that passes the glass sheets after joining the film with the glass sheets, can be cut after that assembly. The lower edge 5 has a convex curve in an arc of a circle. The lower field of the windshield extends, when mounted, under the engine hood. This lower field must be able to be electrically heated, which establishes that the heating wires 8 must extend parallel to the curved lower edge 5. The device comprises a support 10, in which a cylindrical drum 11 having a relatively large diameter is rotatably mounted, on a horizontal axis. The drum 11 is hollow, and the cylindrical wall of the drum is perforated. A vacuum pump, not shown, is connected to the drum 11 by means of a duct 12. The films 1, 2 are maintained on the cylindrical surface of the drum by the suction caused in this way. The diameter of the drum 11 can be selected, for example, in such a way that the two films 1, 2 can be deposited on the circumference of the drum. The two films 1, 2 then occupy more or less the position represented in the drawing, in which the lateral edges 3, 4, adjacent to each other, do not extend parallel to each other, but form one with the other, a relatively large alpha angle. While the heating wires 8 describe on the films 1, 2, at a time, an arc of a circle corresponding to the configuration of the lower edge 5; the arc of circle that describe the heating wires in the area of the angle alpha between the lateral edges 3, 4, presents a curvature opposite to the curvature on the films 1, 2, in such a way that the heating wires present on the surface of the drum seen as a whole, a wavy shape. The constant torque motor 14, which is driven by a regulating amplifier 16, serves to drive the drum 11 in rotation. Above the drum 11, a guide 18 extending parallel to the axis of the support 10 is arranged on the support 10. rotation of the drum 11, on which a carriage 20 that can be moved is mounted. The drive of the carriage 20 takes place by means of a drive screw 21, which is put into rotation by a constant torque motor 22. The constant torque motor 22 is piloted by a regulation amplifier 24. The wire storage device 26, is mounted on the carriage 20. The yarn device comprises a yarn feeding reel 27 mounted on a corresponding support, an electrically heated presser strip 28, which sinks into the film, the yarn coming from the feed reel 27, as well as suitable guiding means, not shown in detail, for the thread of the feeding reel and the pressing slice. A detailed description of such a device, of a wire storage device for depositing a straight wire, appears in EP 0 553 025 Al, to which this point refers. The wire storage device 26 itself is mounted on a vertical shaft 29, which is mounted in rotation on the carriage 20. The angular position of the wire storage device is controlled with the help of the constant torque motor 31. , by means of a gear of conical wheels 30. The constant torque motor 31, is piloted by an amplifier of XQ regulation 32. An essential component of the device is the processor 35 equipped to command the device by means of a program. That processor 35 is provided with an appropriate data memory, in which _L > enter the data for the time-stroke program, on the basis of which, the thread 8 must be arranged on the films 1, 2, and on the cylindrical surface of the drum between the two films 1, 2. In accordance with this program, the processor 35 sends the 2nd regulating amplifier 16 for rotating the drum 11, by means of the control line 36, the regulating amplifier 24, for driving the drive screw 21 in rotation by means of the control line 37, and the regulating amplifier 32 for angularly adjusting the yarn deposit device 26 by means of the control 38. Several carriages 20 each provided with a yarn depositing device, can also be disposed on the guide 18, in such a way that, in the case of a sufficient length of the drum 11, seen in the axial direction of the drum 11, several films can be fixed on the drum and receive a thread simultaneously. When a thread 8 is fixed in the manner described, on the films 1, 2, on the desired surface area, the processor 35 cuts the rotary drive of the drum 11. On each of the strips of copper foil paper 40, which were previously fixed on the films at the level of their side edges and which are superficially tin-plated on the side carrying the thread 8, a second strip of copper foil having a tinned surface is deposited. With the help of a welding iron, the strips of metallic copper paper applied one on the other are welded together, the yarn being included. The threads are then cut to the outside of the films 1, 2, next to the strips of metallic copper paper that serve as current supply conductors. The films 1, 2 are then removed from the drum 11, after having suppressed the depression that reigns in the drum 11 and then machined to incorporate them into the glazing sheets.

Claims (15)

1. NOVELTY OF THE INVENTION Having described the invention, we consider it as a novelty and, therefore, claim as our property, what is contained in the following clauses. A method for depositing and fixing a thin metallic thread on the surface of the thermoplastic film of a sheet glazing, in which the thermoplastic film is maintained by depression on the surface of a cylindrical drum; the drum is rotated; the wire, with the aid of a yarn depositing device comprising a heated crimping tool, a yarn feeding spool and means for routing the yarn from the yarn feeding spool below the heated crimping tool, is deposited continuously on the film due to the fact that a linear feed movement is communicated to the yarn deposition device, on a guide arranged parallel to the drum axis, characterized in that the drive for the linear advance of the yarn deposition device, is sends according to a time-stroke program established in accordance with the desired curved shape of the yarns.
2. 2 . - Procedure according to clause 1, characterized in that the deposit and the fixing of the thread take place during a constant rotation movement of the drum.
3. 3. Procedure according to clause 1, characterized in that the drive is controlled for the rotation movement of the drum, according to a time-stroke program established in accordance with the desired curved shape of the threads,
4. 4.- Procedure according to any of the clauses 1 to 3, characterized in that the angular position of the yarn deposition device is modified in accordance with the respective linear movement of the yarn deposition device.
5. 5. Device for executing the method according to clause 1, comprising a cylindrical drum that can be put into rotation by means of a drive motor and whose hollow space can be put under depression by means of a conduit; the cylindrical wall is perforated to fix the films by suction; a guide is disposed above the drum parallel to the axis of the drum; a carriage can move along the guide and is driven by means of a motor; a yarn device mounted on the carriage comprises a heated press slice that rolls on the surface of the drum or on the films and sinks the yarn into the films; a wire feed spool and means for guiding the wire between the feed spool and the press roll are provided, characterized in that a regulation amplifier is sent by means of a processor according to a time-stroke program corresponding to the curve The desired yarn on the film is disposed behind the drive motor for the linear movement of the carriage carrying the yarn deposition device.
6. 6. Device according to clause 5, characterized in that a regulation amplifier piloted by the processor, is also placed behind the drive motor, for the rotation movement of the drum.
7. 7. - Process according to clause 5 or 6, characterized in that the yarn deposition device is mounted on a shaft mounted rotationally perpendicular to the axis of the drum.
8. 8. Device according to clause 7, characterized in that the angular position of the wire storage device can be controlled by means of a constant torque motor, which is also piloted by the processor in accordance with a time-stroke program.
9. 9.- Plastic film, especially designed to associate it with at least one rigid plate, for example glass, and especially domed, to constitute a glazing and comprising metal wires arranged on its surface, characterized in that the wires are arranged according to trajectories not rectilinear.
10. 10.- Glazing that incorporates the plastic film according to clause 9.
11. 11.- Glazed according to clause 10, characterized in that it has at least one curved edge and in which the wires are arranged along a curved path, especially parallel to the curved edge of the glazing.
12. 12. Glazing according to clause 10 or 11, characterized in that the wires are arranged in the lower area of the glazing.
13. 13. Glazing according to clause 12, characterized in that an opaque layer is deposited on the glass in relation to a part at least of the threads.
14. 14. Application of glazing according to any of clauses 10 to 13, such as encristalado heater with wires that are electrically powered.
15. 15.- Glazing application according to any of clauses 12 or 13, such as glazing heater in low area intended to prevent the windshield wiper blades from sticking in cold weather.