Wind-shield for vehicles and process for its manufacture.

MEMORY

The invention relates to a windshield manufacturing process for automotive vehicles whose lower zone serves as a housing for the windshield wipers in their rest position, arranged below the level of the engine hood.

In automotive vehicles with limpiaparabri. If you are below the level of the engine bonnet, there is a danger that during the cold season of the year the windshield wipers will be blocked on the windshield. In particular, this can happen when it snows, when the snow sliding on the windshield is located in the housing provided for the windshield wipers and thus influences the proper functioning of the windshield wiper.

The objective pursued by this invention is that of. Development of a windshield manufacturing process of the aforementioned type suitable for mounting sunk in the engine hood, in such a way that the windshield wiper can perform its function perfectly even in the cold season of the year.

The invention consists in that, in a manner known per se, the lower area of ​​the windshield is provided with an electric heating resistance, and that the lower area with the resistance in a plane situated between the resistance and the windscreen wipers, is provided with an opaque and absorbent layer of heat irra diado.

For reasons of windshield design with the manufacturing process, the following advantages are achieved:

- The part of irradiation of the heat developed by the heating resistance raises the temperature of the surface of the glass on which the windscreen wipers rest, in such a way that the heating performance of the plates rises.

- As the absorbent layer is opaque at the same time, the heating resistance is hidden from the outside. This allows the use of heating conductors, which in case of visible arrangement would damage the aesthetics.

- The opaque layer prevents the view from the outside of the body parts that remain behind this part of the windshield. This is particularly important because the aforementioned parts are difficult to access. and the dirt accumulated in them would be visible through the windshield.

- The opaque layer can be extended upwards in such a way that in the event that the windscreen sticks to the body above the heating zone with the aid of paste paste, the inevitably irregular contour of the latter can be disguised.

According to a first embodiment of the invention, the base of the manufacturing process, the windshield is a glass plate composed of thermoplastic intermediate layer and incorporated resistance cables, and the opaque and absorbing layer of radiated heat is disposed on the outer plate of silicate glass, either on its internal face adjacent to the thermoplastic intermediate layer, or on its external face opposite it. In the arrangement of the opaque layer on the free face on which the windshield wiper rests directly, said layer must be made of a durable and wear-resistant material, such as an enamel layer.

According to a preferred embodiment, the electric heating resistance consists of heating conductors treated at high temperatures in a composition similar to the enamel and also the opaque and absorbing layer of irradiated heat, it is an enamel-type layer treated in the oven at high temperatures. The heating resistance can also be composed of a continuous layer of metal or semiconductors.

If these layers are arranged on the rear external face, that is, on the surface opposite to the windshield wipers, it is advisable to dis. Place a new enamel layer on the electric heating conductors, located through the opaque layer, on the glass surface. This ca pa serves as a protective layer of the conductors of cationing against the corrosive attack of the atmosphere, to which the heating conductors would otherwise be exposed.

In a progressive development of the invention, it is seen that the opaque and absorbing layer of radiated heat located between the windscreen wiper and the heating resistance has a thermal conductivity equal to or greater than that of the glass plate. In case the heating resistance is ready. Between two opaque layers, the opaque layer opposite the wiper blade may show a lower thermal conductivity than the opaque layer disposed between the heating conductors and the wipers.

Object of the invention is the manufacturing process of a preferred form of windshield consisting of first providing on the surface of a glass plate to the silicate a compact closed layer of coasion paste with the help of the screen printing method, drying the layer and on the same print the heating and drying drivers, and on the heating ducts also a new compact layer of printable cooking paste, subjecting the superimposed layers to a process of heat treatment in the oven.

Other characteristics and advantages of the invention emerge from the claims and from the following description, explained by way of example on the basis of the drawings of different executions. The drawings show:

Figure 1 - a windshield manufactured according to the invention in assembled arrangement, represented as part of a longitudinal cut along the middle axis of the vehicle.

- Figure 2 - a first windshield execution object of the invention, partial.

exposed as a drawing.

-Figure 3 - another execution of the windshield, partially represented in the drawing.

The windshield (l) is arranged upper and laterally in a profile frame (3) of the body (2). For fixing on the frame (3) the glue string (4) is used. The embellisher profile (5) top cap and laterally the glue layer to the outside. Below the windscreen (1) is attached with the help of the glue string (6) to the stringer that limits the contour of the body underneath.

The windshield (1) extends downwards beyond the junction line with the body and enters the hollow space (8), in which the wiper motor is arranged. The windshield wipers (10) rest in their resting position on the part of the windscreen that extends into the hollow space (8). The engine hood (11) terminates at such a distance from the windshield (1), that it allows the windscreen wipers to exit through the gap. In the represented rest position, the windshield wipers (10) are in the lowest position, that is, below the edge (12) of the engine hood (11) in such a way that they are not seen from the front and they do not represent any obstacle for the current of air along the for breezes.

The windshield (l) is electrically heated in the area (15) fixed for the housing of the windscreen wipers and provided with an opaque layer. The opaque layer extends upwards beyond the glue string (6), such that the upper limit (16) runs above the edge of the glue string (16).

This way, the glue tape remains in this place, where a beautifying profile can not be placed, covered by the layer opeca.

The manufacture of the windscreen (1) is shown in FIG. 2, in which the assembly by layers is partly represented by the drawing. The windshield here shown is a composite glass plate, consisting of a glass plate exterior to the silicate (18), a glass plate internal to the silicate and a thermoplastic intermediate layer (20) of butyral polyvinyl 3 3 on the plate of glass to the interior silicate (19), in the lower area (15), which is one fifth of the total height of the windshield, a closed absorbent layer opaque to light (21) is provided based on a dark enamel, preferably black. On this layer of glaze (21) rests a second layer covering the heating conductors (22) and side collectors (23), fixedly attached to the enamel layer (21) located below. The heating conductors (22) and the collectors (23) are, as usual, of an enamel type conducting metal, especially of a conductive silver composition. The collectors (23) have flat extensions (24) for the case that is pre. soldered connection elements and those do not have the proper width on which soldered such ele. connection items not represented here.

A continuous layer (26) of the same material as the layer (21) located directly on the glass surface is arranged on the conductors (22) and the manifolds (23). This layer (26) laterally has catches (27), to free the surfaces (24) for the welding of the connecting elements.

The layers (21) to (26) are arranged according to the case of Figure 2 on the outer surface of the inner glass plate (19). Its contribution is made successively before the bending of the glass plates to the silicate (18) and (19), by means of the screen printing method, once the previous layer disposed is dry. The three successively added layers are jointly subjected to firing during the heat treatment of the two superposed glass plates (18) and (19) in the bending furnace, in which the glass plates are heated to softening temperatures, and melt in a compact and adherent layer structure on the glass surface.

The heat absorbing layer (21) corresponds in its coefficient of surface expansion with that. of the heating conductors (22) including the manifolds (23). Since in the embodiment shown in FIG. 2 the conductors (22) extend over the entire width of the plate, the arrangement of these layers on one of the surfaces of the silicate glass plates is not without problems (18). ) and (19) adjoining the thermoplastic intermediate layer, if both silicate glass plates are curved together.

There is a danger that when the plates are fused and baked, an adhesion or interlock with the other glass plate will occur, so that the separation of both glass plates after the assembly is bent can not be done without difficulties.

To overcome this problem, the execution form, represented in FIG. 3, can be chosen, provided that it is desired to arrange, the heating conductors on the outer plate, more energy-appropriate. Requirement for this is that the accommodation area of. The windshield wipers in their resting position are in the center of the plate, so that the heating is only necessary in the center of the plate. j

The execution according to figure 3 is represented in the drawing. The outer silicate glass plate (28) ,. it is attached to the inner silicate glass plate. (29) through the thermoplastic intermediate layer (30) of butyral polyvinyl.

On the planar glass plate (28) a closed ceramic layer (31) of a dark ceramic color which can be imprinted by means of the screen printing method is provided in the intermediate zone provided for heating. After drying of this layer (31), the heating conductors (32) and the collectors (35) j · of a printable silver paste are applied with the aid of the screen printing method. The connection surfaces (34-) to the collectors (33)^varL arranged on the lower edge of the glass plate.

On the inner glass plate (29) a layer (36) of the same ceramic color is applied on its outer surface as the layer (31) with the help of the screen printing method. It is, the layer (36) extends to toc

I the width of the glass plate (29) and forms the opa layer. ca, while the layer (31) primarily represents the function of absorbing the radiated heat. The intermediate thermoplastic layer (30) has with respect to the connection surfaces (34-) recesses (37) for the connection elements, which are welded to the co-faces. nexion (34 ·) and whose contact tongue protrudes from the composite glass plate, downwards.

For the joint curved glass plates (28) and (29) are grouped after the supply and drying of the layers (31), (32), (33) and (3θ) · Since in the curved conjunn to under action gravitational both glass plates and due to the higher temperature of the outer skin, they are opened in some measure the layers (31), (32) and (33) at the temperature at which they melt and on the surface of the glass plate (28) cook and do not come into contact co. the surface of the glass plate (29).

If later the glass plate (29) after the temperature equilibrium rests again on the glass plate (28), in the area of ​​the layer (31), the layers (31) i (32) and ( 33) are in the meantime hardened such that they no longer meet the surface of the plate (29).

It is understood that the ceramic colors used for the qpacas and abosrbente layers on one side and the silver pastes used on the other side for the printing of the heating conductors, must correspond. ponderse in its composition in such a way that in the treatment to the oven to the same temperature there are no interferences between them.

Such ceramic products are commercially available, for example in the firm ΒΙίϊΤΗΕ COLOURS Β. V. and precisely as black ceramic colors in the oven '-' ··· with baking temperature between 580 and 6202 C. under the brand 39-269 / 5/63 and as a silver paste with tempera, baking temperature also between 580 and 620S C. under the brand SMW 197 / AS - 70% / l8 / 63-