WO1993011387A1 - Discharge lamp projector, particularly working projector or motor vehicle light - Google Patents

Abstract

The disclosed projector is comprised of an optical unit (10) provided with a discharge type lamp (13). An integrated electric unit provides power for the lamp, and comprises least a high voltage ignitor, the optical unit and the electric unit being mounted in a common dismountable case. In said case, the optical unit and the electric unit are supported by two separable elements (29, 40), of which one supports the electric unit and the other supports a power supply wire for the electric unit, each of the two elements also carrying a respective connector member (36, 46) connected, respectively, to the power supply wire and to the electric unit so that breaking of the circuits of the elements causes the concomitant disconnection of the connector members and the switching off of the supply of the electric unit before the possibly live internal members become accessible.

Description

 Discharge lamp headlamp, in particular work lamp or motor vehicle headlamp

The invention relates to a headlamp provided with a lamp of the so-called “discharge lamp” type.

The invention advantageously applies to the production of a work light or a motor vehicle headlight, but is in no way strictly limited to these particular applications. We know the advantages of discharge lamps, which have been recently proposed as light sources for motor vehicle headlamps, and which were already commonly used for public and road lighting. Compared to halogen lamps usually used in automotive headlamps, discharge lamps have in fact a very large number of advantages: light efficiency at least triple (therefore providing a much higher luminous flux for a power supply less), high color temperature, very long service life, insensitivity to shock and vibration (due to the absence of fragile filament), dimensions comparable to those of a halogen lamp.

However, discharge lamps, unlike conventional halogen lamps, cannot be directly connected to the vehicle's power supply: it is necessary to insert a "ballast", to automatically adapt the electrical energy available to characteristics of the lamp in order to start it (high voltage ignition phase, of the order of 12 to 15 kV), to ensure its operation at a nominal constant power (regulation function ), and finally allow re-ignition after an interruption of operation of any duration. Essentially, a discharge lamp supply ballast comprises a low voltage part, receiving the available electrical energy (typically, a direct voltage of 12, 24, 36 or 48 V) and transforming it into an alternating current. by a DC / AC converter, and a high voltage part or "igniter" delivering to the lamp the starting voltage of the order of 15 kV for the duration necessary, this voltage then falling back to a value of the order of 80 to 100 V once the lamp has started.

In view of these high voltages, a certain number of precautions, which hitherto had no place with conventional halogen lamps, must be taken to protect the user when the latter wants to access the projector, for example to disassemble it and exchange the lamp.

The most commonly used solution for automotive headlamps is to provide a switch (microswitch) opening the ballast supply circuit when the user opens the hood of the vehicle: the ballast (which is outside the optical unit) is then automatically disconnected, which provides the desired security.

This solution however involves the installation of an interrupter, with all the corresponding disadvantages: addition of an element on the supply circuit, more complex wiring, higher cost and above all risk of malfunction in the event that the switch contact blades would remain glued.

One of the aims of the invention is, therefore, to propose a new concept of discharge lamp projector ensuring intrinsic security during any attempt to dismantle the lamp, without there being any need to place a any switch on the projector power line wiring.

In addition, in the case of a work light, the solution con¬ sisting in providing a safety switch actuated by the opening of the hood cannot be retained, since these headlights are generally external to the vehicle body.

Another object of the invention is therefore to propose a headlight concept making it possible to ensure total security even for headlights entirely external to a vehicle. To this end, the invention essentially consists in integrating all or part of the ballast into the headlamp housing and in providing a connection means which, by means of appropriate internal connection means, automatically switches off the power supply during dismantling. of the housing. In this regard, the following will be called "electrical block" the ele- elements of the ballast integrated into the projector housing, this electrical block being able to be constituted either by the whole of the ballast - that is to say both the low and high voltage parts, the “electric block” then being directly connected to the vehicle supply - either by only part of this ballast, this part including the igniter

(high voltage part); in the latter case, the projector is powered by an external low voltage block, without danger of electric shock for the user, this low voltage block possibly being common to several projectors, a low voltage block given ali - then lying several igniters mounted in parallel at the output thereof.

More specifically, the projector of the invention is .characterized in that it comprises an integrated electrical block for supplying the lamp comprising at least one high-voltage igniter, the optical block and the electrical block being mounted in a housing removable common, and in that, in this housing, the optical unit and the electrical unit are carried by two separable elements, one of which carries the electrical unit and the other carries a supply wire of the electric unit, each of these two elements also carrying a respective connector member connected, respectively, to the power supply wire and to the electrical block, so that the disjunction of these two elements causes the concomitant disconnection of the connector members and the powering off of the power supply of the electrical block before the internal organs possibly under tension become accessible.

In one embodiment, that of the elements which carries the electrical block is provided with a hatch allowing, after opening, the removal of the electrical block without disjunction of the two elements, and the electrical block is mechanically integral with the connector member. tor connected to it, so that the withdrawal of the electrical unit by the hatch causes the concomitant disconnection of the connector organs.

The lamp can be plugged directly into a socket integrated in the electrical unit. In the latter case, the electrical unit can be directly attached to the optical unit, the electrical unit comprising means for centering the lamp on the optical unit.

Furthermore, the electrical unit can be geometrically dis¬ posed so that the center of gravity of the projector is located essentially in line with a mounting device associated with this projector.

We will now describe exemplary embodiments of the invention with reference to the accompanying drawings, in which the same numerical references designate similar elements.

Figure 1 is a cross section, in elevation, of a first embodiment of the projector of the invention.

FIG. 2a schematically illustrates the power supply system for prior art discharge lamp projectors, FIGS. 2b and 2c being homologous to FIG. 2a for two possibilities of supply circuit of the projector of the invention.

Figure 3 is a rear view, along m-III of Figure 1, of the front part of the projector housing of the invention. Figure 4 is a section along IV-IV of Figure 3, of the same front part.

Figure 5 is a front view, along V-V of Figure 1, of the rear part of the projector housing of the invention.

Figure 6 is a top view of the projector of the invention, showing its various constituent elements.

Figure 7 is a cross section, in elevation, of another embodiment of the projector according to the invention.

Figures 1 and 3 to 6 illustrate a first embodiment of a work projector incorporating the teachings of the invention.

This projector comprises an optical unit 10, of structure in itself conventional, with a reflector 11 and a closing glass 12. The closing glass 12 is optionally provided with specific prisms studied as a function of the geometry of the light source in order to optimize the yield.

This optical unit is provided with a discharge type lamp 13 fixed to the reflector 11 of the optical unit from the rear, the lamp being mounted on a removable lamp holder 14 provided with electrical outlets 15. This lamp is by example a standard type lamp "Dl", mounted on a standard lamp holder.

This lamp is powered by an electrical circuit designated by the general reference 20 in the diagrams of FIG. 2. The circuit shown in these various diagrams comprises a supply battery 21 delivering a direct voltage, generally understood between 12 and 48 V, to a ballast 22 comprising a low voltage part 23 and a high voltage part or "igniter" 24 (the respective roles of these low and high voltage parts have been explained above); the discharge lamp 13 is supplied by outputs from the high voltage block 24.

Until now, the elements of the ballast 22 were, as illustrated in FIG. 2a, external to the projector and produced in the form of a separate housing, security being ensured by means of an interrup¬ tor 25 placed in series on the supply line 26, between the battery 21 and the low voltage part 23.

One of the essential characteristics of the invention consists in incorporating into the headlight housing, in whole or in part, the elements of the ballast 22, as illustrated in FIGS. 2b and 2c.

In the case of FIG. 2b, the only high voltage part 24 (igniter) has been integrated into the headlight housing, the low voltage part remaining placed in a block external to the headlight; this solution makes it possible in particular to supply two or more igniters with a single low voltage block. This configuration corresponds to that illustrated in Figures 1 and 3 to 6.

In the case of FIG. 2c, all of the elements of the ballast, low and high voltage, have been integrated into the projector casing, the projec¬ tor then being directly connected to the battery by line 26, in exactly the same way than for a halogen lamp projector classic type gene. This second possibility corresponds to the configuration of the embodiment of FIG. 7, detailed below.

If we return to Figures 1 and 2 to 6, which therefore correspond to the diagram of Figure 2b where only the igniter is disposed in the projector housing, we see that this igniter 24 is disposed in a housing 31 d 'a rear part 30, forming a casing, of the casing of the pro¬ jector, the other part of this casing being constituted by a front part or door 40 which fits and is screwed onto the rear part 30. The two parts 30 and 40, which therefore constitute two third half-housings, retain in place, when assembled, the optical unit 10 between two flanges 32 and 42, with the interposition of a peripheral seal 50 ensuring both the maintenance of the optical unit 10 without damaging it and sealing the interior volume of the projector.

The two half-housings 30 and 40 are assembled by screws introduced from the front, passing through the reinforced orifices 43 of the half-housings 40 (FIG. 3) and coming into the orifices 33 (FIG. 5), which will be self-tapped, from the rear half-casing 30. The half-casings 30 and 40 comprise, in the lower part, a respective volume 34, 44 serving for the passage of the electrical supply conductors.

More specifically, the volume 44 receives, as can be seen in particular in Figure 3, the power cable from the low voltage block outside the projector (block 23 in Figure 2). This wire leads to a first connector element 45 comprising a plurality of female pins 46, here three in number (two wires plus a mass).

The rear half-housing 30, for its part, has in its lower part 34, a homologous connector 35 (see FIG. 5 as well as FIG. 4 where this connector has been shown in broken lines) provided with male pins 36. These pins 36 are connected to the igniter 24 carried by this half-casing 30, the male pins 36 possibly being, in an advantageous embodiment, constituted by contact tabs emerging directly from the igniter tor 24, produced in the form of an overmolded block.

The electrical connection between the igniter 24 and the contacts 15 of the lamp 13 is ensured, as can be seen in FIGS. 5 and 6, by two wires 27 connecting the high voltage outputs 28 of the igniter to the contact terminals 15 of the base 14 carrying the discharge lamp. This high voltage connection is located entirely inside the half-casing 30, the wires 27 leaving the housing 31 containing the igniter 24 by slots 37 made in the vertical wall before this housing 31 (FIG. 5). Finally, the rear half-casing 30 comprises in the rear part a hatch 28 allowing access to the ballast 24 without dismantling the projector, for example to remove the latter. This hatch is for example fixed by four screws and provided at the periphery with an appropriate rib making it possible to seal against runoff.

The whole of the projector is mounted on an orientable ball 39 used for fixing the projector to the desired location and for adjusting the beam in the chosen direction.

Preferably, the position of the ballast 24, which is with the optical unit 10 the heaviest element of the projector, is chosen so that the center of gravity G of all the elements of the projector is located substantially at right of the support 39, this in order to reduce the incidence of vibrations which could be transmitted by this support to the projector. It can be seen that, with the headlight structure which has just been described, the separation of the two half-housings 30 and 40, for example to access the lamp holder to allow a lamp change, will immediately cause the separation of the two connector elements 35 and 45, thus causing the disconnection of the power supply to the igniter and therefore the elimination of any risk of electric shock for the user having to dismantle the housing and change the lamp.

Thus, access to the power cable 27 of the lamp (high-voltage cable) is only possible after separation of the two elements 35, 45 from the housing, that is to say after the igniter was disconnected from its low voltage supply box, causing the power supply to be cut off and any high voltage in the projector to disappear.

We also note that this configuration ensures the same security during the extraction of the igniter by opening the hatch 38 without dismantling the housing: the contact blades 36 thereof, guided in the connector element 35, come to separate the female pins 45 when the igniter 24 is removed. FIG. 7 illustrates a second embodiment, in which the whole of the ballast (low and high voltage parts) is placed in a block molded 29, itself fully disposed inside the housing of the projector.

In addition, in this embodiment, the cables connecting the lamp to the igniter have been eliminated by directly mounting the optical unit 10 on the electrical supply unit 29. More specifically, the reflector of the optical unit 10 is provided with a perforated peripheral ring 16, integral with the reflector and receiving the electrical unit 29 fixed by screws such as 17; other embodiments are of course possible, for example lugs coming from molding in the case of a reflector produced by injection. The reflector also carries a flange 18 making it possible to center the electrical unit 29 on the optical unit 10, the centering and the axial positioning of the lamp being obtained by a countersink 19 formed on the electrical unit. The high voltage supply is supplied directly by studs 28 coming into contact with the homologous elements 15 of the lamp holder (if a lamp is provided with a specific base allowing rear centering and contact making by studs, can thus dispense with the lamp holder and high-voltage wires connecting the lamp holder to the igniter). In this embodiment, the safety connector 45, which carries the pins 46 connected to the vehicle battery, is no longer integral with the half-housing 40, but with the ferrule 16 itself integral with the optical unit. The other connector element is constituted, as in the previous embodiment, by the contact blades 36 supplying the electrical block. The optical unit + electrical unit assembly, once assembled, is placed in the rear half-housing 30, inside which it will be mechanically retained in place by screwing the front half-housing 40.

It will be noted that, unlike the previous embodiment, it is not the disassembly of the two half-housings 30 and 40 which provo¬ that the cut of the power supply, but the disassembly of the electrical block assembly 29 + optical unit 10 (disassembly necessary to access the lamp). This does not however create any additional risk, insofar as this assembly does not include any high voltage element accessible from the outside.

Claims

1. A headlight, in particular a work light or a motor vehicle projector, comprising an optical unit (10) provided with a discharge type lamp (13), characterized: - in that it comprises an integrated electric block (22; 24) for supplying the lamp comprising at least one high-voltage igniter (24), the optical block and the electric block being mounted in a removable common housing, and - in that, in this casing, the optical unit and the electrical unit are carried by two separable elements (30, 40; 29, 40), one of which carries the electrical unit and the other carries a power supply ¬ tion of the electrical block, each of these two elements also carrying a respective connector member (36, 46) connected, respectively, to the supply wire and to the electrical block, so that the disjunction of these two elements causes the concomitant disconnection connector organs and de-energizing the power supply to the electrical unit before any internal organs, possibly energized, become accessible. 2. The headlight of claim 1, wherein: - the one (30) of the elements which carries the electric block is provided with a hatch (38) authorizing, after opening, the withdrawal of the electric block without disjunction of the two elements, and - The electrical unit is mechanically secured to the connector member (36) which is connected to it, so that the removal of the electrical unit by the hatch causes the concomi¬ tant disconnection of the connector members. 3. The projector of one of claims 1 and 2, wherein the lamp is directly plugged into the electrical block. 4. The projector of claim 3, in which the electrical unit is directly fixed to the optical unit, the electrical unit comprises bearing means (18, 19) for centering the lamp on the optical unit. 5. The projector of one of the preceding claims, wherein the electrical block is geometrically arranged so that the center of gravity (G) of the projector is located essentially in line with a mounting device (39) associated with this projector .