EP0586308B1 - Connector and high voltage lamp assembly, especially for a vehicle - Google Patents

Description

The present invention relates generally to high voltage lamps for projectors, in particular for motor vehicles.

Discharge lamps are known for their high luminance and excellent energy efficiency. We are currently seeking to use them in motor vehicle headlamps, replacing conventional halogen lamps.

A problem linked to the use of this type of lamp is that it requires a large voltage at its terminals, in particular for its ignition. Special precautions must therefore be taken so that, when working on a projector fitted with such a lamp (especially for its replacement), the operator does not run any risk of electric shock.

Furthermore, since the connectors used for mounting this type of lamp are exposed to an extremely high voltage, which can reach several tens of thousands of volts, in order to be able to withstand such voltages, both in the locked and unlocked positions, they must be very bulky. To solve this problem, the parts to be connected, namely the lamp base and the connector itself, are designed so that once fitted, one or more baffles are arranged between the two contacts. By choosing a suitable material for the connector walls and a sufficient thickness, it prevents the formation of electric arcs outside the lamp, both by drilling and by routing, the potential path of routing being too long due to the present baffles.

The second drawback of such a connector is that an arc can easily strike there, and then be maintained there, when the male and female parts to be connected are not locked, or are incompletely locked. In an attempt to overcome this problem, the lamp supply circuit can be designed to be able to distinguish, as a function of the voltage between its output terminals and the intensity of the current which it delivers, an arc appearing in the badly locked connector of the arc developed in the lamp (and which constitutes its nominal load). However, the time required for the circuit to carry out this recognition is relatively long, of the order of 0.1 seconds, since the transient priming phases which precede are not significant. In addition, the distinction between different types of arcs from simple measurements of voltage and current intensity requires significant computing power. This is why before its detection is actually made, the arc has generally already had the time to damage the connector and to generate degrading fumes for the surrounding elements, in particular for the mirrors of the projectors.

There is already known from EP-A-0 282 119 a safety device forming an electrical indicator of the presence of the lamp base in the connector, so that any attempt at ignition is prohibited as long as the lamp is removed. This device has the characteristics set out in the preamble of claim 1.

This known device is however subject to the axial translation of the lamp in its connector, and is therefore not able to testify to the good locking of the lamp in particular when this locking is effected by mutual rotation of the base and the connector (case by example of bayonet systems). In addition, this known device is of relatively complex and expensive construction.

Furthermore, EP-A-0526335 is cited under Article 54, paragraphs (3) and (4) of the EPC.

It describes a set of connector and high-voltage lamp comprising first and second contacts for supplying the lamp and a third contact capable of coming into contact with the second contact when the lamp is correctly positioned.

The invention aims to overcome these drawbacks of the assembly according to EP-A-0 282 119.

To this end, it proposes a set of connector and high-voltage lamp having the features of the characterizing part of claim 1.

Preferred, but not limiting, aspects of this assembly are set out in the dependent claims.

Other characteristics and advantages of the invention will become apparent from the description and the appended drawings, which show preferred embodiments thereof.

• la figure 1 est une vue de face d'une lampe et du conducteur destiné à la recevoir, une partie du culot de la lampe ainsi que le connecteur étant coupés axialement ;
• la figure 2 est une vue de côté du connecteur de la figure 1, avant mise en place de la lampe ;
• la figure 2A est une vue partielle similaire à la figure 2, illustrant la mise en place de la lampe ;
• les figures 3 et 3A sont des représentations partielles, en coupe transversale, montrant la liaison du type "à baïonnette" entre le culot et le connecteur, les plans de coupe correspondant respectivement aux plans III et IIIA des figures 2 et 2A ;
• les figures 4 et 4A sont des vues de détail schématiques montrant une variante d'agencement des contacts électriques additionnels, respectivement en position d'appui mutuel et en position écartée l'un de l'autre ;
• la figure 5 est une vue partielle en coupe transversale d'un culot dans un connecteur, dans un autre mode de réalisation des contacts additionnels, ceci au cours de la mise en place de la lampe ;
• la figure 5A est une vue similaire à la figure 5, après mise en place correcte de la lampe dans le connecteur ;
• la figure 6 est un schéma de montage électrique illustrant la manière dont les deux contacts additionnels peuvent être branchés à un circuit de commande de l'alimentation de la lampe.

In these figures:

• Figure 1 is a front view of a lamp and the conductor for receiving it, part of the lamp base and the connector being cut axially;
• Figure 2 is a side view of the connector of Figure 1, before installation of the lamp;
• Figure 2A is a partial view similar to Figure 2, illustrating the placement of the lamp;
• Figures 3 and 3A are partial representations, in cross section, showing the connection of the "bayonet" type between the base and the connector, the section planes corresponding respectively to the planes III and IIIA of Figures 2 and 2A;
• FIGS. 4 and 4A are schematic detail views showing a variant arrangement of the additional electrical contacts, respectively in the position of mutual support and in the position separated from one another;
• Figure 5 is a partial cross-sectional view of a base in a connector, in another embodiment of the additional contacts, this during the installation of the lamp;
• Figure 5A is a view similar to Figure 5, after correct placement of the lamp in the connector;
• Figure 6 is an electrical circuit diagram illustrating how the two additional contacts can be connected to a control circuit of the lamp supply.

The reference 4 designates a connector capable of receiving, removably, the base 2 of a discharge lamp 1. The connector 4 is for example mounted inside a headlight housing, not shown, equipping a motor vehicle . This connector 4 comprises a jacket 5 consisting of a tubular envelope 51 and a flat bottom 52. As shown in FIG. 2, the jacket 5, generally cylindrical, of axis A , has a part 53 extending laterally by compared to the rest of the shirt. An electric cable 500, composed of the various conducting wires for supplying the lamp and for connecting additional contacts, arrives in this part 53.

Inside the jacket 5 is mounted a cylindrical body 40 used to receive the base 2 of the lamp. As is well known, the body 40 comprises a cavity 41, in the form of a circular crown and of section with a square contour, shaped to receive a male end part 21 integral with the base 2 of the lamp, and affecting the shape of a crowned. In the space 20 inside the crown 21 is fixed a cylindrical stud 24, coaxial with the base 2, and adapted to fit into a split socket 44 housed inside the extra thickness 42 surrounding the cavity 41 of the connector. The axis of this central socket 44 corresponds to the axis A of the connector 4. On the outer edge of the cavity 41 of the connector is mounted an elastic tongue 45 made of conductive material. The end 43 of this tongue is bent to form a dihedral, the edge of which is directed towards the inside of the connector.

The base 2 of the lamp has a generally cylindrical shape, of axis B. It is provided, at the outer wall of the part 21, with a part 23 of conductive material (forming electrical ground contact). The latter is adapted to come into abutment against the part 43 of the tongue 45 when the male part 21 comes to fit into the cavity 41. At the same time, the stud 24 comes to fit into the split socket 44.

The stud 24 and the part 23 are connected by suitable conducting wires 240, respectively 230, to the two electrodes of the bulb 10 of the discharge lamp 1.

The sleeve 44 and the tongue 45 are similarly connected to conductive wires 440, respectively 430 constituting the power cable 500. The latter is supplied with electricity from the battery fitted to the vehicle, via a control and supply circuit of a type known per se.

All the contacts and conductive wires are of course electrically insulated in the base 2 and in the connector 4, by the interposition of appropriate insulation elements.

By simply observing FIG. 1, it is understood that if the lamp 1 is moved coaxially towards the connector 4, the stud 24 is fitted into the socket 44 and the contact of the end of the tongue 43 with the part 23. This gives a pair of complementary electrical contacts used to supply the lamp, as is well known.

The base 2 carries a pair of pins 3 directed radially, and diametrically opposite. These pins are adapted to penetrate grooves 50 of profile in the shape of an "L" formed in the upper edge of the tubular part 51 of the jacket 5. The engagement of the pins 3 in the grooves 5, by translation, then axial rotation , constitutes a bayonet connection, of a type which is also well known.

According to the invention, the connector is equipped with a pair of additional contacts, these consisting of two tabs 60, 61 made of conductive metal. These tabs are carried by a mounting piece 62 fixed to the outside of the jacket 50, opposite the end of one of the grooves 50. They extend vertically; the tongue 50 is rigid, and is positioned so that its free end is located substantially opposite the closed end of the groove 50. The other tongue 61 is flexible. It extends vertically, parallel to the tongue 60 and at a short distance from the latter. Its upper end is provided with a bent part at a right angle to form a cross-member 611 engaging in the groove 50 (see in particular Figure 1).

At its upper part, on the side facing the fixed tongue 60, the tongue 61 is provided with a small boss 610. The transverse part 611 is made of non-conductive material. It is provided with a small boss 612 facing the entrance to the groove 50 (that is to say on the side opposite to the boss 610).

The pair of tabs 60, 61 constitute the two elements of an electrical indicator (6) for correct fitting of the lamp, the operation of which will now be explained.

In the absence of a lamp, the tongue 61 is normally moved away from the fixed tongue 60, as shown in FIG. 2.

When the lamp is placed in the connector, the operator begins by bringing each of the nipples plumb with the entry of the grooves 50. The nipple 3 thus positioned at the entry of the groove equipped with the indicator 6 is shown in broken lines in Figure 2. The operator then moves the lamp axially, as shown by the arrow f in Figure 2 and the stud, designated 3 'in this same figure, is housed in the vertical branch of the groove in "L" 50. When this movement of translation is completed, the electrical contacts 24, 44 and 23, 43 are obtained. However, the lamp is not locked in the connector. For this, the user must rotate the lamp relative to the connector around their common axis A , B , so as to engage the pins 3 in the horizontal branches of the grooves 50. At the end of this movement, one of the pins - designated 3 '' in FIG. 2A - encounters the boss 612 on its path and deforms the tongue 61 so as to apply the conductive boss 610 against the end of the fixed tongue 60. The two tongues 60, 61 are thus brought into physical contact with each other, and the conduction between the two tabs is therefore ensured.

Of course, if the lamp is removed, the contact 61 automatically moves away from the fixed contact 60, owing to its elasticity, and the conduction is again broken (position in FIG. 2).

It is easy to understand that this change of situation can advantageously be used as a source of information on the good locked state of the lamp in the connector. If this locking is insufficient, the pins 3 are not sufficiently advanced at the bottom of the grooves 50, and the tongue 61 is not stressed enough to bear against the tongue 60. The pair of contacts 60, 61 thus constitutes a switch whose open or closed state will be used to control, by means of appropriate conductive wires each connected to one of the contacts, the control circuit of the lamp supply. This is to prevent the power from being unintended while the lamp is removed or has been incorrectly mounted. The formation of undesirable electric arcs cannot therefore be done.

In the variant of the electrical indicator 7 shown in FIG. 4, the location of the two contacts is reversed with respect to that which has just been described. The fixed contact, designated 70, is this time located in front of the movable contact, referenced 71, if we consider the direction of movement of the stud 3 when it moves towards the bottom of the slot 50 in view of the lamp locking, direction symbolized by the arrow F in FIG. 4A.

In the absence of a lamp or during an incorrect assembly, the two contacts 70, 71 are normally applied one against the other, by means of a conductive boss 710 carried by the contact 71. As in the previous embodiment, the contact 71 is flexible and has a transverse part engaging inside the groove 50 (not shown). It carries a small boss 711 against which comes to bear the stud 3 at the end of the locking (arrow F , FIG. 4A), which has the effect of separating the contacts 70, 71 from one another, preventing thus the electrical conduction between these two elements.

FIG. 6 illustrates an exemplary embodiment of an interface between the two contacts 70, 71 and an electronic control circuit M controlling the electrical supply of the lamp. This circuit is for example equipped with a microprocessor or a microcontroller of known type.

Each of the contacts 70, 71 is connected by a conductor X , respectively Y , to two input terminals of the circuit M. The conductor Y is connected to ground, while the conductor X is connected to a DC voltage source G , via a resistor 9. The potential difference implemented is for example 5 Volts. The two conductors X and Y are connected by a capacitor 90 and a Zener diode connected in parallel. These two components provide, in a well known manner, protection of the circuit against overvoltages.

In the absence of a lamp in the connector, or when the lamp is incorrectly mounted, the contacts 70 and 71 are in mutual support, so that the conductor X is grounded. Circuit M detects this situation to then prohibit the supply of the lamp.

On the contrary, when the lamp is correctly in place in the connector, the contacts 70, 71 are separated from each other and the conductor X is at the potential of 5 Volts while the conductor Y is at the potential 0. The circuit M then authorizes the supply of the lamp.

The electrical indicator 8 shown in Figure 5 is of a different design. The two electrical contacts, referenced 80 and 81, are mounted in the jacket 51 so as to be flush while making slightly protruding from the inner wall of the shirt. They are angularly offset by a certain angle u .

The base 2 is provided with a conductive piece 200 in the form of an angular sector positioned opposite the contacts 80, 81. It is for example a thin copper strip. Its arc length is slightly greater than the angle u .

The conductive strip 200 is positioned in such a way that when the pins are engaged in the groove inlets 50 (in a position similar to the position referenced 3 ′ in FIG. 2) it is applied against only one of the contacts 81. On the other hand, after rotation of the base 2 around the axis A , B , symbolized F in FIG. 5A, over a sufficient stroke corresponding to the arrival of the pins at the bottom of the horizontal parts of the grooves 50, the strip 200 also comes to bear against the other contact 80. It then ensures electrical conduction between the contacts 80, 81, and this state can then be used as information for controlling the control circuit M.

Claims (8)

1. High-voltage connector and lamp assembly, notably for a motor vehicle, in which the lamp (1) has a cap (2) suitable for being engaged in a cavity (41) in the connector, fixing means (3, 50) ensuring the mounting and assembly of the cap (2) with the connector (4), the latter each carrying a pair of complementary electrical contacts (23-43; 24-44) for supplying the lamp (1) and also having an electrical indicator (6, 7, 8) of the presence of the lamp, which comprises a pair of additional electrical contacts (60, 61; 70, 71; 80, 81) electrically separate from the pair of contacts supplying the lamp and carried by the connector (4), as well as actuating means controlled by the relative positions of the cap (2) and connector (4), able to modify the electrical conduction between these two additional contacts only when the lamp is present in the connector, characterised in that the actuating means operate by means of a relative rotation movement of the cap (2) and connector (4) for their mutual locking, the said electrical indicator forming a locking indicator.
2. Assembly according to Claim 1, characterised by the fact that one (60; 70) of the additional contacts is fixed, whilst the other (61, 71) is movable, the said actuating means comprising a pusher (3) fixed to the cap (2) and able to move the movable contact (61; 71) in order to move it closer to or further away from the fixed contact (60; 70) during the mounting of the lamp in the connector.
3. Assembly according to Claim 2, in which the fixing of the cap (2) in the connector (4) is a bayonet fixing, comprising at least one pair of lateral pins fixed to the cap (2), which engage by axial translation and rotation in recesses (50) with an L-shaped profile, formed in a sleeve (51) fixed to the connector (4), characterised by the fact that the said pusher (3) is formed by one of these pins.
4. Assembly according to one of Claims 1 to 3, characterised by the fact that the said movable contact (60, 61) consists of an elastically deformable conductive blade.
5. Assembly according to one of Claims 2 to 4, characterised by the fact that, in the absence of a lamp, or when the latter is incorrectly mounted, the movable contact (61) is away from the fixed contact (60).
6. Assembly according to one of Claims 2 to 4, characterised by the fact that, in the absence of a lamp, or when the latter is incorrectly mounted, the movable contact (71) is in abutment against the fixed contact (70).
7. Assembly according to one of Claims 1 to 6, characterised by the fact that the said additional contacts (60, 61; 70, 71; 80, 81) are each connected, by means of a conductor (X, Y), to the electronic circuit (M) controlling the power supply to the lamp.
8. Assembly according to Claim 1, characterised in that the additional contacts are mounted in a casing (51) of the fixing means (50), so as to be flush whilst projecting on the internal wall of the casing, these two contacts being angularly offset by an angle (u), whilst the cap (2) is provided with a conductive piece (200) in the form of an angular sector with a length of arc slightly greater than the angle (u), the latter ensuring electrical conduction between the two contacts (80, 81) only if it is connected with these two contacts at the same time.

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