MXPA99009007A - Electrical connection stud - Google Patents

Abstract

A terminal stud (1) to be applied to an electrically conductive material (14) on a glass surface (15) to form a strong unobtrusive connection for an electrical supply wire is provided by a stud comprising a hollowed base plate (7) to receive solder to secure the stud to the conductive material (14), the said base plate (7) having an outer periphery to contact the conductive material (14), the stud further comprising a rim (5, 6) extending from the said outer periphery in a direction externally to the said base plate (7) to provide an attachment for a connecting clip (2) of an electrical supply lead. The stud (1) is particularly concerned with the provision of electrical supply to a conductive material carried on the surface of a window such as a vehicle window.

Description

TERMINAL FOR ELECTRICAL CONNECTION The present invention relates to a terminal for electrical connection, to be used in the connection of a power supply cable to a conductive element on a glass surface. Said terminal is particularly intended for the provision of electric current to a conductive material that is applied on the surface of a window, such as for example a vehicle window. Electrically conductive materials, for example in the form of film, grids and tapes, are increasingly used on glass surfaces for a plurality of purposes. Films or electrically conductive grids are used as heating elements for windshields and windows of automobiles, for windshields of aircraft and trains, and even as glass panels for buildings. Said heating elements commonly include a collecting strip for each side of the window, with horizontal conductive filaments extending across the width of the window from one collecting strip to the other, but alternatively they may be constituted by a uniform thin conductive film which is extends through the entire surface of the window. Films, grids or conductive tapes can alternatively be used as radio antennas. The conductive tapes can be used as alarm wiring on glass panels, activating an alarm signal if the tape breaks. There are many proposals for the configuration and ibication of terminals for said elements. It is a common goal that the terminal provides a firm and reliable contact with a conductive element, at the same time that it is shaped and located to be as little as possible. In general, the terminal is firmly secured to the element by welding. Problems usually occur in heated windows due to internal stresses that occur at the interface between the glass and the terminal, as a result of the difference between the thermal ditalation coefficients of the glass and the metal constituting the terminal, or of a metallic conductor to the which terminal is fixed. Because the terminal is usually small, it tends to provide a significant localized heat concentration, which affects both the adjacent glass and the weld that holds the terminal in place. The internal tensions appear especially during the welding of said terminal to the element, during the operation of a heating element and when the glass is exposed to heat, such as solar radiation. Said internal stresses can result in the detachment of the glass terminal, as well as fissures in the glass in the vicinity of said terminal. Consequently, many of the previous proposals have been aimed at reducing such internal tensions. Another problem is that many of the previously proposed terminals have free or protruding portions, which often scratch other adjacent glass panels during transportation or storage prior to installation. This requires that the exposed flexible parts of the terminal must be covered and / or held in a less noticeable position on the panel, using, for example, adhesive tape. The French patent application 2670070 (070) discloses glass panels with conductive elements, especially for the heated rear window of a vehicle, in which the terminals are provided with small projections on the face that is in contact with the glass, so that said protrusions prevent the clamping welding from being displaced from its position. In the specific configuration illustrated with 070, the terminal is constituted by a flat portion, generally in the shape of "E", whose outer side arms are welded to the element and to the inner side arm, which is longer than the outer side arms., and is free to receive a connection terminal, which is fixed to the electric power supply cable for the element. European patent 0023121 claims a heated window terminal with a connecting arm (a conduction area), in which an electrical connection and at least one connecting foot can be made, shaped in such a way that a first flat portion of each foot of bonding is in the vicinity of the heating grid and a second flat portion of each bonding foot is welded to the heating grid. His illustrated version includes two such linking feet.

French patent application 2630863 relates to a terminal for electrical connection located on a support, such as a glass panel. The terminal comprises a base plate, typically in the form of "E" or "C", which is fixed by at least part of its surface to a manifold on the support and to a projection extending perpendicular to the base . Said projection, which is preferably cylindrical or conical, is connectable to a complementary part, which in turn is connected to a power supply cable. Said complementary part is intended to be fixed to the projection by applying pressure perpendicular to the base. The Belgian patent 792573 relates to a glass sheet having an electrical circuit, in particular an automobile windshield having a radio antenna formed by a metal strip in the shape of a "T", in which said circuit has an extreme portion enlarged, to which a connection terminal is fixed. It illustrates a connection terminal "welded to the end portion and constituted by a hollow cylinder with a circular base plate of a diameter slightly larger than the cylinder." A connecting cable to the radio is inserted into a lateral hole provided in the cylinder, which is threaded therein to receive a set screw French patent application 2618264 relates to a power supply terminal for glass with electrical conductors or electrical equipment, said terminal being formed as a hollow rivet or a pressure terminal said terminal is particularly intended to be encapsulated in a rubber material.

Although the above proposals have, to a certain extent, reduced the problems of overheating and scratch deterioration, their solutions have proved cumbersome, for example because they require terminals with many components, protection for packaging or encapsulation of the terminals. These solutions imply additional costs, not only in materials but also in operations such as placement, removal and, in some cases, disposal of the respective materials. The object of the present invention is to provide a simple connection terminal with an improved configuration with respect to those known in the art. According to the invention, a terminal terminal is provided which is applied to an electrically conductive material (14) adhered on a glass surface (15), said terminal being characterized in that it comprises a recessed base plate (7) apt to receive material of welding to secure the terminal with the conductive material (14), said base plate (7) having a peripheral contour that makes concact with the conductive material (14), the terminal further comprising one. crown (4) projecting from said peripheral contour of the base plate outwardly with respect to said base plate (7) to provide a fixation for a connection clamp (2) of an electrical power supply conductor. The terminal is generally located in a portion of the element that serves as a conductive conductor strip. It provides a convenient point at which a corresponding clamp is fixed, from which an electric power supply cable extends. The terminals for terminals in accordance with the present invention provide a problem-free compact terminal, which has several advantages over the terminals of proposals of the prior art. In mechanical terms, the recessed base plate of the terminal allows a significant amount of welding material to be disposed between the bottom surface of the terminal and the electrically conductive material applied to the glass. Said recessed surface also has a more substantial area for the adhesion of the welding material than a flat surface of the same perimeter. These factors ensure a firm fixing of the terminal on the glass. The outer ring allows fixing with the connection clamp around the periphery of the terminal, thus providing a substantial contact zone between the terminal and the clamp, which brings benefits in the stability of the fixation. A hollow profile is also more favorable for keeping the weld melt under the crown, thus preventing the weld material from spilling onto the glass. These spills are common when using terminals or flat bases, which are at the same time unattractive and harmful for the resistance to the separation of said terminals. In electrical terms, the significant surface of snore that exists between the welding material and the terminal terminal helps to establish a good electrical connection between said terminal and the conductive material applied to the glass. The significant contact surface between the periphery of the terminal and the connection clamp also provides a good electrical connection, avoiding the "hot spots" that can appear with connections made in a small projection of the conductive material. In thermal terms, a recessed base post allows the relatively large surface area of the solder material in contact with the conductive material to dissipate the heat generated during welding. This reduces the concentration of heat applied to the interface between the conductive material and the glass, significantly limiting the thermal stresses applied to the glass during the welding as a result of the different coefficients of expansion of the conductive material and the glass. The configuration of the terminal according to the present invention allows its manufacture from a single piece of metal until achieving the necessary conformation to receive the connection clamp. This avoids the problem that arises with most of the previous terminals of a moving part that can be inadvertently bent during transport or storage to a position where it can scratch or snag the adjacent glass sheets. Consequently, the need to use adhesive tape to hold said moving parts in position is avoided, saving the cost of the tape and the operative steps necessary to apply, remove and remove said tape and to clean the adhesive residues from the glass. The configuration of the recessed base plate also allows an easy application of terminal terminals using a robot. The terminals can be stacked in a cartridge and distributed by the tip of a soldering iron of an automatic device to fix the terminals to the glass. The recessed portion of the terminals may be conveniently loaded with a preformed portion of welding material before they are introduced into the cartridge. The terminals offer the advantage that they can be constructed in one piece, the base plate and the outer crown being formed of a single sheet metal, typically by a combination of stamping and cutting operations. Preferably, the terminal terminal according to the invention has a circular cross section in a plane parallel to the plane of the glass. A circular cross section facilitates the supply and location of the terminal, as well as its attachment to a connection clamp. It also avoids positioning problems, which can arise with a traditional non-circular cross section when fixing the terminal to the conductive material, since an exact orientation of the crown with respect to the conductive material is required. The circular cross section also facilitates the action of fixing the terminal to the connection clamp. Preferably, the part of the base plate that is in contact with the conductive surface includes at least one groove. In the case of a circular terminal, said groove is preferably a continuous circular groove around the periphery. Said grooves also reduce the surface area of the terminal that is in direct contact with the conductive material, which results in an effective reduction of the interface area between the materials with very different coefficients of thermal expansion, thus reducing the thermal stresses in this interface. Preferably the terminal includes at least one hole extending through the base plate. This allows an additional evacuation of the heat originated during the welding or during the operation of a heated window. It also allows a welder to be applied through a hole in direct contact with the welding material, which is not only more convenient than an indirect application but also allows the welding temperature to be reduced (typically from 270 ° C to 220 ° C), consequently reducing the energy costs of the operation. A further advantage is that the preformed portion of welding material mentioned above can be stapled into the hole to be held in that position during storage in a stack of cartridges and during its distribution and application at the point of welding, thereby facilitating the fixing the terminal to the conductive material by means of a robot. If a single hole is used, it should preferably be located in the center of the recessed area and should preferably be circular in shape. If several holes are used, the preferred configuration is to have a substantially central hole and at least four holes disposed around it. These latter holes are preferably rectangular with the configuration of elongated slots having their longer sides located outwardly with respect to the central hole, and they should preferably be located equidistant from one another. These multiple orifices offer the advantage of making the baseplate more easily deformable, thus limiting the degree of mechanical stresses applied to the conductive material and to the glass during welding. In a convenient configuration according to the invention, the base plate has a single hole of generally cruciform shape. Said hole preferably includes a generally circular central portion, through which the tip of the welder can pass for welding, and elongated slots as described above, but in this case opening from the central portion. The hollow or cavity is generally convex, although it should be understood that said form does not need to follow a regular curve. One possible configuration is that it be hoarse-conical. In a convenient embodiment of the invention the terminal and the corresponding clamp are shaped to provide a pressure fastener. This can be achieved by forming the crown of the terminal as a cone, truncated at the periphery of the base plate of said terminal. For an identical height of the terminal, a conical side face provides an area greater than a cylindrical face of the same diameter as the periphery of the base plate. This larger surface promotes the dissipation of heat during the welding of the terminal or during the operation of a heated element to which the terminal is fixed. Preferably, the outer crown of the terminal is provided with a peripheral rim, to which the corresponding clamp carrying the electric power supply cable can be fixed. If said clamp includes around its periphery a flexible ring or flexible teeth, these can be made in a size congruent with the flange, so as to provide a pressure action when the clamp is pushed into place on the terminal. Said cooperative action between the peripheral flange and the clamp further favors a firm connection between them, which gives little opportunity for the clamp to be released inadvertently. Said peripheral rim can be conveniently provided by making the crown present frusto-conical configuration, with the smaller diameter portion at the end in contact with the periphery of the base plate. In the simplest form of said crown-conical crown, the peripheral rim is provided by the larger diameter portion of the truncated cone. In an alternative form, the peripheral flange is provided by a cylindrical portion extending from said larger diameter portion of said frusto-conical portion of the crown. In a further alternative form, said peripheral rim is provided by forming the crown portion by two frusto-conical portions, inverted one with respect to the other and with their larger diameter portions abutting to create the peripheral rim. In another alternative embodiment of the terminal, the crown comprises a cylindrical portion in contact with the periphery of the base plate and a frusto-conical portion whose larger diameter portion is in contact with the cylindrical portion of the crown to create a flange in the place where said portions meet. In this version of the terminal, the cylindrical portion of the crown allows the rim to be larger than with a crown composed of two frusto-conical portions. This ensures a good electrical contact between the terminal and the corresponding clamp. Preferably, the crown is provided with perpendicular slots from the periphery of the base plate to the upper edge of the crown. This configuration facilitates the clamping operation of the corresponding clamp. It also ensures the dissipation of heat during the welding of the terminal. Preferably, the terminal is made of material based on Cu (copper). Said material has the advantage of having excellent electrical and thermal conductivity. The corresponding clamp can be covered with a cap of any suitable shape and material. Said cap is provided especially for aesthetic reasons. Additionally, it can ensure electrical isolation of the terminal and the corresponding clamp. The invention will be described in more detail with reference to the accompanying figures, in which: Figure 1 illustrates a bottom view of a terminal low profile terminal according to the invention (for example as seen before the welding, through a glass sheet on which the terminal will be mounted Figure 2 is a side sectional view of the terminal illustrated in Figure 1, taken along the line AA 'of Figure 1. This figure illustrates the terminal arranged on a conductive layer on a glass sheet Figure 3 illustrates a bottom view of a modified version of the terminal illustrated in Figure 1, without side slits in its crown and with multiple holes in its base plate, but still According to the invention, Figure 4 is a bottom view of a modified version of the terminal illustrated in Figure 1, without lateral grooves in its crown and with a single hole generally cruciform in its base, but still in accordance with the invention.

Figure 6 illustrates a side view (taken from the same direction as Figure 4 but on a slightly smaller scale) of a complementary bracket to be fixed to a terminal as illustrated in Figures 1 to 5, and which is intended to receive and Secure an electric power supply cable. Figure 7 illustrates a plan view of the complementary brace of Figure 6 (seen from above as illustrated by arrow F in Figure 6). Figure 8 illustrates a perspective view, from below, of the clamp of figure 6 when it is fixed to the terminal of figure 1. Figure 9 illustrates a perspective view, from below, of a clamp of the figure 6 already attached to a terminal of figure 1. Figure 10 illustrates a side view of a complementary hood to be fixed to a complementary bracket as illustrated in figure 6. Figure 11 illustrates a plan view of the hood of the figure 10 (seen from the direction illustrated by arrow G in Figure 10). The terminals illustrated in FIGS. 1-11, indicated generally by the reference number 1, are generally circular in configuration. The terminal 1 comprises a crown portion 4 and a frusto-conical base plate 7. In FIG. 2 it is illustrated in a position on a sheet of conductive material 14, which in turn is applied on a sheet of glass 15. When the terminal is in position as illustrated in Figure 2, the base plate 7 forms a cavity 12 between the terminal 1 and the conductive material 14. The base plate 7 has a central circular hole 9. In the area where the base plate 7 and the crown portion 4 are joined and the terminal 1 makes contact with the conductive material 14, a circular groove 11 is formed on the inner face of the terminal 1. The crown portion of the terminals illustrated in the figures 1-4 have two complementary cylindrical and frusto-conical parts "" 5 and 6. Part 5 is in contact with the periphery of the base plate 7 and with part 6. The larger diameter of part 6 is slightly larger than the diameter of part 5, forming a peripheral rim outgoing 13 in the place where said parts are joined. The total portion of the crown 5, 6, 13 provides a particularly convenient attachment for a complementary connection clamp generally similar to that of Figures 5-8. The frusto-conical surface 6 is useful for aligning the clamp prior to being pushed into position on the clamp. The protruding flange 13 has a configuration that allows a firm engagement with the peripheral teeth of the clamp. The lateral grooves 3 perpendicular to the periphery of the base plate 7 are provided in the crown 4. Said grooves facilitate the clamping of the complementary clamp on the terminal, as well as the dissipation of the heat during its welding. The terminal versions illustrated in FIGS. 3 and 4 are generally similar to those illustrated in FIGS. 1-2, and like parts are indicated with the same reference numbers as in FIGS. 1-2, with the exception that the terminals of FIG. Figures 3 and 4 do not have side slits. The version of figure 3 differs in that radial rectangular holes 10 are provided in the base plate 7. The version of figure 4 differs in that the central circular hole 9 is combined with rectangular rectangular holes 10, by extension of the rectangular holes 10 until reaching the central circular hole 9, thereby forming a single cruciform hole 29. This hole configuration is easier to construct than the separate orifice version of Figure 3, and additionally provides additional flexibility within the terminal when said terminal is subject to heating. The illustrated terminal has an outer diameter of 13.5 mm and a height of 4 mm. It is preferably applied to the conductive material 14 from a dispensing cartridge (not shown) with a solder pellet already in place in the recess 12. A soldering iron (not shown) is brought into direct contact with the soldering material through the solder. from hole 9, producing the fusion and solidification of said welding material. The resolidified welding material completely fills the recessed space 12 between the terminal 1 and the conductive material 14. Most of the heat generated during the welding can be evacuated from said hollow space 12 through the hole 9 and by conduction and radiation from the surface The outer heat of the terminal 1. The residual heat at the interface between the welding material and the conductive material 14 is dissipated over this relatively large interface, so that the intensity of the heat applied on the lower glass 15 is significantly reduced. The terminal version illustrated in Figure 5 is generally similar to that illustrated in Figures 1-4, and similar parts are indicated with the same reference numbers as in Figures 1-4, except that the terminal of Figure 5 does not It has lateral clefts. The version of figure 5 differs in that the crown 5 has two complementary frusto-conical parts 50 and 60. The part 50 has its smaller diameter at the end in contact with the periphery of the base plate 7 and its wider diameter in contact with part 60 at its widest diameter. The larger diameter of the part 60 is slightly larger than the wider diameter of the part 50, thus forming a protruding peripheral rim 130 at the place where said parts meet. The total crown portion 50, 60, 130 thus provides a convenient fixation for a complementary connection clamp, generally similar to that of Figures 6-9. The frusto-conical surface 50 is useful for the alignment of the clamp prior to being pushed into its position in the terminal. The protruding peripheral rim 130 has a configuration that allows a firm engagement with the peripheral teeth of the clamp. The complementary clamp illustrated in Figures 6 to 9 is used with the terminal as described above with reference to Figures 1 to 5. This complementary clamp, generally indicated by the reference number 2, comprises a flat plate 20 with a portion circular end 21 of diameter slightly larger than the peripheral flange 13 of the terminal terminal. The side of the circular portion 21 intended to seat on the terminal has six peripheral teeth 22, each of which has a shoulder 25 projecting inwardly shaped to snap into the flange 13 of the terminal when the clamp is pressed on the terminal . At the opposite end from the circular portion 21 the flat plate 20 has sets 23 and 24 of fastening straps that receive the end of an electric power supply cable (not shown) and that are crushed on the cable when it is in place. position. The illustrated clamp and clamp provides a low profile terminal, which is easily applied to a required surface and which is especially easy to apply by robots. The application of the terminal to a conductor adhered on a glazed surface involves a very low risk of a deterioration due to heat in the glass. The conical shape of the hole that receives the welding material serves to contain said welding, as well as to avoid spills of unpleasant appearance. The welded terminal adheres firmly to the required surface. It has been demonstrated by tests that a force of 270 N is required to separate it, which is well above the level of forces that the terminal could receive. Additionally, it is possible to obtain said strong adhesion without the need for an unattractive enlargement of the terminal. In fact, its conformation is such that it does not need to be hidden, for example by encapsulation. The terminal placed on a coated glass sheet has a conformation such that it is very unlikely that it will cause damage to adjacent sheets or other articles during its transfer. Figures 10 and 11 illustrate a cap generally indicated by the reference number 30. Said cap improves the aesthetic appearance of the already fixed terminal and its corresponding clamp, and can also isolate them electrically, provided that it is made of an appropriate insulating material.

Claims (15)

1. CLAIMS 1. Metallic terminal terminal to be applied on an electrically conductive material (14) on a glass surface (15), characterized in that said terminal comprises a base plate aahuecadada (7) intended to receive welding material to secure said terminal to the conductive material (14), said terminal further comprising a crown (4) protruding from said peripheral contour of the base plate in an outward direction with respect to said base plate (7) to provide a fixation for a connecting clamp ( 2) of an electric current conductor. Terminal terminal according to claim 1, characterized in that the part of the base plate (7) that makes contact with the surface of the conductive material (14) includes at least one groove (11). Terminal terminal according to claim 1 or claim 2, characterized in that it has at least one hole (9) extending through the base plate (7). Terminal terminal according to claim 3, characterized in that it has a single hole (9), which is located substantially centrally to the recessed area. 5. Terminal terminal according to claim 4, characterized in that said hole (9) is a circular hole. End terminal according to claim 3 or 4, characterized in that the base plate has a single hole (29) of generally cruciform shape. Terminal terminal according to claim 6, characterized in that the orifice (29) includes a generally circular central portion. Terminal terminal according to any one of the preceding claims, characterized in that it is shaped to provide a press-fit fastener for the connection clamp (2). End terminal according to any one of the preceding claims, characterized in that the outer ring (4) is shaped like a cone, truncated at the periphery of the base plate (7). Terminal terminal according to any one of the preceding claims, characterized in that the outer ring (4) has a flange (13) to which the connection clamp (2) can be fixed. Terminal terminal according to any one of the preceding claims, characterized in that it has a circular cross section in a plane parallel to the plane of the glass surface (15). End terminal according to claim 9, characterized in that the outer crown (4) comprises a cylindrical part (5) and a frusto-conical part (6), with the widest diameter portion of the frusto-conical part (6) joined to the cylindrical part (5) to form the flange (13). 13. Terminal terminal according to claim 9, characterized in that the outer crown (40) comprises two frusto-conical portions (50, 60) inverted one with respect to the other, with their wider diameter portions abutting to form a flange (130). End terminal according to any one of the preceding claims, characterized in that the crown (5) is provided with slots extending perpendicularly from the periphery of the base plate (7) to the top of the crown. Terminal terminal according to any one of the preceding claims, characterized in that it is made of copper-based material.