US3732415A

US3732415A - Headlight construction

Info

Publication number: US3732415A
Application number: US00075503A
Authority: US
Inventors: G Lindae
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1969-10-15
Filing date: 1970-09-25
Publication date: 1973-05-08
Anticipated expiration: 1990-05-08
Also published as: DE1951978B2; DE1951978A1; AT304703B; ES162374U; GB1266994A; ES162374Y; JPS4917716B1; SE380079B; NL7015062A; FR2065400A5; BE757515A

Abstract

A cupped reflector is provided in its crown with an opening and has an open side opposite the crown. Its inner reflecting surface is to be protected against deleterious matter in the ambient temperature. A lens seal-tightly closes the open side and an incandescent bulb is received in the reflector and includes a socket lodged in the opening of the crown and having a radially projecting circumferential flange encircling and seal-tight with the socket. Mounting means removably mounts the bulb in the opening in seal-tight cooperation of the socket and flange with the reflector so that the interior of the reflector is pressuretightly and seal-tightly closed with respect to the ambient atmosphere.

Description

United States Patent [191 Lindae 1 May 8, 1973 [54] HEADLIGHT CONSTRUCTION [75] Inventor: Gerhard Lindae, Leonberg, Germany [22] Filed: Sept. 25, 1970 [21] Appl. No.: 75,503

[30] Foreign Application Priority Data Oct. 15,1969 Germany ..P 19 51 978.9

[52] US. Cl. ..240/41 SC, 240/413, 240/41 BM, 313/318, 174/1705 UNITED STATES PATENTS 9/1968 Cibie ..240/413 12/1940 Anklam ..240/41 BM 2,175,361 10/1939 Reger et a1. ..174/17.05 X

586,055 7/1897 Olan ...174/17.05 X 1,640,867 8/1927 Workman ..240/41 BM 2,017,714 10/1935 Frech et al.... .....240/41 BM 2,137,424 11/1938 Thomas..... ..313/318 2,259,451 10/1941 Bennett ..174/1705 X Primary ExaminerSamuel S. Matthews Assistant Examiner-Richard M. Sheer AttorneyMichael S. Striker [57] ABSTRACT A cupped reflector is provided in its crown with an opening and has an open side opposite the crown. lts inner reflecting surface is to be protected against deleterious matter in the ambient temperature. A lens seal-tightly closes the open side and an incandescent bulb is received in the reflector and includes a socket lodged in the opening of the crown and having a radially projecting circumferential flange encircling and seal-tight with the socket. Mounting means removably mounts the bulb in the opening in seal-tight cooperation of the socket and flange with the reflector so that the interior of the reflector is pressure-tightly and sealtightly closed with respect to the ambient atmosphere.

10 Claims, 2 Drawing Figures PATENTE D HAY 81973 Fig.1

A13 Array/v5 HEADLIGHT CONSTRUCTION BACKGROUN D OF THE INVENTION The present invention relates generally to headlight constructions, and more particularly to a headlight for automotive vehicles or the like.

There are at this time in use two basically different types of headlight constructions for automotive vehicles and similar applications. One of these is the socalled sealed-beam type of headlight wherein the reflector and the filament are united in a unit which is sealed in a glass or similar envelope and which is discarded in toto when the filament or the envelope become damaged. In these sealed-beam headlights the interior of the construction is totally protected against any deleterious ambient influences until and unless the envelope should become damaged in some way. This is highly advantageous but it is also rather expensive when the unit must eventually be replaced in toto.

The other type of headlight construction is the more conventional one which has essentially seen use since the time automotive vehicles were first provided with headlights. Specifically, it utilizes a cupped reflector the open side of which is provided for protective and for light-dispersing purposes with a lens of glass or synthetic plastic material, whereas the crown of the cupped reflector is provided with an opening through which an incandescent bulb is inserted into the interior of the reflector. If damage results to the bulb for any reason, for instance if the filament burns out, the bulb is simply replaced with a new one. It is hardly necessary to emphasize that the expense of replacing one such bulb with another is substantially smaller than the expense involved in replacing a sealed-beam unit with another.

The present invention is concerned with the second type of headlight construction, that is the type utilizing a replaceable incandescent bulb as opposed to the sealed-beam type of unit.

In the type of headlight construction to which the present invention is directed, it is customary in modern practice to manufacture the reflectors by a drawing process from sheet steel. This is then coated with a special lacquer and the interior surface of the reflector receives by vacuum-deposition a reflective layer of aluminum. This very thin aluminum layer is highly susceptible to moisture, which damages it rapidly, then of course making the replacement of the entire reflector with a new one an imperative.

Because of this susceptibility the deposited reflective aluminum layer is usually coated with a thin layer of quartz. This has some advantages but it has been found that in many instances the protective quartz layer -which necessarily is also very thin--is still not sufficient to protect the aluminum layer properly. A logical step, which has been taken in the art, was to suggest water-tightly sealing the interior of the reflector. Unfortunately, it was found that even this does not provide complete protection against deterioration of the reflective aluminum layer. The reason is that, even if the aluminum layer is completely protected against access of moisture, the usually sulfur-containing industrial gases which are present in the ambient atmosphere in many locations as pollutants-are capable of penetrating to the interior of the reflector despite water-tight sealing. Their effect upon the aluminum layer is to cause a corrosion of the latter and over a period of time the reflection factor afforded by the reflector decreases steadily under such circumstances until 'the reflector must be replaced even if the aluminum layer is protected against access of moisture.

SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to provide an improved headlight construction of the type under discussion which is not possessed of the aforementioned disadvantages.

More particularly it is an object of the present invention to provide an improved headlight which entirely and completely protects the deposited metallic reflective layer on the inner reflective surface of its reflector against deleterious matter present in the ambient atmosphere.

An additional object of the present invention is to provide such a headlight which affords the desired advantages in a very simple and therefore inexpensive construction.

In pursuance of the above objects, and others which will become apparent hereafter, one feature of the invention resides in a headlight for automotive vehicles or the like which, briefly stated, comprises a cupped reflector having a crown provided with an opening, an open side opposite the crown, and an inner reflecting surface which is to be protected against deleterious matter in the ambient atmosphere. Lens means sealtightly closes the open side and an incadescent bulb is received in the reflector and includes a socket lodged in the opening of the reflector and having a radially projecting circumferential flange encircling and sealtight with the socket. Mounting means removably mounts the bulb in the opening in seal-tight cooperation of the socket and flange with the reflector so that the interior of the latter is thereby sealed with respect to the ambient atmosphere and access of deleterious matter from the ambient atmosphere to the reflecting surface is precluded.

It will be appreciated, thusly, that a significant portion of the sealing effectiveness of the incandescent bulb with reference to the opening in the crown of the reflector, is afforded by the fact that the radial flange itself is seal-tight with the socket of the bulb.

I am-able to obtain a particularly seal-tight and pressure-tight arrangement between the flange and the socket if the flange is in form of a discrete annular member an inner circumferential marginal zone of which is of frustoconically convergent configuration and surrounds the outer peripheral surface of the socket with which it defines an annular groove of substantially wedge-shaped cross-section, and which groove is completely filled with a substance connecting the flange member with the socket and at the same time providing a seal-tight connection between the two.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects" and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a somewhat diagrammatic axial section through a headlight embodying my invention; and

FIG. 2 is a somewhat diagrammatic end-elevational view, on an enlarged scale, of the outer end of the bulb socket shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing in detail it will be seen that reference numeral 1 identifies in toto a parabolic cupped reflector which in conventional manner is produced by a drawing process from sheet steel. It has an open side provided with a cylindrical ring portion 2 in which the lens 3of glass or synthetic plastic material and serving both for protecting the interior of the reflector and for distributing the light in the desired manner-is seal-tightly and pressure-tightly mounted, usually by being bonded or adhesively secured in place. This is conventional and requires no further discussion especially because it is not a part of the present invention.

The crown of the reflector l opposite the open side of the latter is provided with a circular opening which terminates in a cylindrical sleeve-like portion 5. An incandescent bulb 4 is arranged in this opening, and more particularly the glass envelope 6 of the bulb 4 is located in the interior of the reflector l and communicates in known manner at its open end with the metallic sleeveshaped socket 7. Of course, this is not specifically illustrated because it is a completely conventional expedient in the bulb-making art, and all that need be remembered is that a suitable bonding material bonds the portion of the glass envelope 6 which extends into the socket 7, to the latter.

The inner surface of the reflector 1 is provided in conventional manner with a reflecting surface, that is usually with a vapor-deposited layer of aluminum, which must be protected not only against moisture but according to the present invention against other deleterious matter in the ambient atmosphere, such as gaseous pollutants of a nature which could attack and destroy the reflective surface.

According to the present invention the socket 7 is provided with a radially projecting circumferential flange 8 which serves for fixing the position of the bulb' tion 5, and in turn the flange 8 abuts against the flange 10. An additional sleeve 11 is inserted into the sleeve 9 from the outside, and an annular sealing ring 12 is compressed between the sleeve 11, the sleeve 9 and the flange 8, thus affording a pressure-tight seal in conjunc tion with the fact that the sleeve 1] is peened over or otherwise suitably retained against displacement in and with reference to the sleeve 9 and the reflector 1. Thus, the bulb 4 itself serves to afford a pressure-tight sealtight closure of the interior of the reflector I against the entry into the latter of deleterious matter in the ambient atmosphere. 0n the other hand, the bulb 4 is not mounted in such a manner that it could not be replaced. Instead, it is a relatively simple matter to embodiment is a discrete annular member which is adhesively bonded to the metallic socket 7, or which is soldered to the latter.

In the illustrated embdiment-but not necessarily-a particularly pressure-tight connection between the flange 8 and the socket 7 has been achieved by configurating the inner marginal zone bounding the center opening in the flange 8and identified with reference numeral l3-as a conically convergent portion which defines with the outer circumferential surface bounding the socket 7 an annular groove 14 of preferably substantially wedge-shaped cross-section. This groove 14 is then completely filled with whatever substance is used to unite the flange 8 with the socket 7 both mechanically and seal-tightly, that is either a suitable adhesive or a soft solder substance, identified diagrammatically in the drawing with reference numeral 14a. It is the purpose of this latter construction to so increase the diffusion path through the substance 14a that during the possible pressure differences between the interior space 15 of the reflector and the ambient atmosphere, no gas can diffuse through the substance 14a. It will be appreciated that such pressure differences can result because temperatures may develop in the interior of the reflector during conventional operation of a vehicle provided with such a headlight, which may range between substantially 30 and +1 20 C so that the pressure in the interior of the reflector 1 changes in a range between substantially 600 and 1,100 Torr as a result of the gas expansion and gas contraction caused through such temperature fluctuations.

Of course, it is a concomitant necessity to seal the incandescent bulb 4 itself in order to prevent an exchange of gases between the interior 15 of the reflector l and the ambient atmosphere. Conventionally,an evacuation aperture 16 is provided in the insulating member 17 which closes the outer open'end of the socket 7, and through this aperture 16 the interior of the envelope 6 and the socket 7 is evacuated once the two have been bonded togethen'lt is necessary to close the aperture 16 pressure-tightly because otherwise 'it would be possible for gas to diffuse into the interior of the reflector 1 through this opening and from therebetween the juncture of socket 7 and glass envelope 6 through the bonding material which is used to unite the two and which is not gas-tight. Usually the insulating member 17 is of synthetic plastic material and it is therefore advantageous to pressure-tightly seal the evacuation aperture 16 by means of a synthetic plastic material of suitable type which is applied into and over it.

Further, it is necessary to prevent the difiusion of gas into the interior of the socket 7 and from there through the juncture between the socket 7 and the envelope 6 into the interior 15 of the reflector 1, which diffusion could occur at the juncture between the metallic socket 7 and the insulating member 17 itself. This is accomplished in that the insulating member 17 is adhesively and pressure-tightly bonded to the socket 7 interiorly oras indicated at 18 in the illustrated embodimentexteriorly via a two-component adhesive or any other thermosetting adhesive suitable for the intended purpose.

Finally, it will be appreciated that it would also be possible under certain circumstances for gas to diffuse into the interior of the sleeve 7 or socket 7 past the solder connection 19 where the terminals 20 are connected with the end portions of the non-illustrated filament accommodated in the envelope 6. To prevent this the solder connections must be such that the diffusion of gas through them is impossible, for instance by making them in such a manner that the solder material provides a long enough path to make the diffusion of gaseous matter from the exterior to the interior impossible.

By resorting to the present invention the reflecting surface in the interior of the reflector l is completely protected against access by deleterious matter present in the ambient atmosphere. This makes it possible to even avoid the provision of the otherwise very customary protective quartz layer over the reflective surface. Thus, the construction according to the present invention affords the advantages of the sealed-beam units while being substantially simpler and less expensive to make, therefore being less expensive to sell and having the additional advantage of being reusable if the bulb 4 becomes damaged, simply by replacing the bulb with a new one.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a headlight for automotive vehicles or the like, it is not intended'to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying -current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In a headlight of the removable-bulb type for automotive vehicles and the like, in combination a reflector assembly comprising a cup-shaped reflector having a larger-diameter front opening and a smaller-diameter rear opening, a first cylindrical sleeve extending through said rear opening into the interior of said reflector and having at the front end of said sleeve a radially inwardly projecting annular support ledge, said reflector having an inner reflecting surface to be protected from deleterious atmospheric matter; lens means seal-tightly closing said front opening; a bulb assembly comprising a cylindrical socket containing a bulb, an annular member encircling said socket and in cluding a radially outwardly extending stop flange and defining with said socket an annular groove diverging in direction away from said bulb, and a sealing mass in said groove seal-tightly encircling said socket, said bulb assembly being lpcatedin said reflector assembly with said flange abutting against said ledge rearwardly of the latter to properly position said bulb assembly; an annular sealing ring in said sleeve rearwardly of said flange; and removable securing means for holding said flange against said ledge and said sealing ring against said flange and comprising a further cylindrical sleeve fitting into said first sleeve rearwardly of said sealing ring.

2. In a headlight as defined in claim 1, wherein said socket and said flange are of metallic material.

3. In a headlight as defined in claim 1, said flange being a discrete annular member having a center opening bounded by a frustoconically convergent marginal circumferential zone, and said socket extending through said center opening and having an outer peripheral surface defining with said marginal circumferential zone said annular groove, and said sealing mass completely filling said annular groove, sealing the juncture between said socket and member and connecting the latter to the former.

4. In a headlight as defined in claim 3, wherein said groove is of substantially wedge-shaped cross-section.

5. In a headlight as defined in claim 3, said socket and member being of metallic material, and said sealing mass being solder.

6. In a headlight as defined in claim 3, wherein said mass is an adhesive substance.

7. In a headlight as defined in claim 1, said socket having an open rear end portion; an electrically insulating member closing said open end portion; and bonding means pressure-tightly bonding said insulating member to said open end portion for preventing entry of atmospheric matter into the latter.

8. In a headlight as defined in claim 7, wherein said insulating member is of synthetic plastic material.

9. In a headlight as defined in claim 7; further comprising terminals provided on said insulating member exteriorly of said socket, and a filament located in said bulb and having connecting portions pressure-tightly soldered to the respective terminals.

10. In a headlight as defined in claim 7, said insulating member having an evacuating aperture for evacuating the interior of said bulb and socket; and sealing means pressure-tightly sealing said aperture subsequent to evacuation for preventing the entry of said deleterious matter.

Claims

1. In a headlight of the removable-bulb type for automotive vehicles and the like, in combination a reflector assembly comprising a cup-shaped reflector having a larger-diameter front opening and a smaller-diameter rear opening, a first cylindrical sleeve extending through said rear opening into the interior of said reflector and having at the front end of said sleeve a radially inwardly projecting annular support ledge, said reflector having an inner reflecting surface to be protected from deleterious atmospheric matter; lens means seal-tightly closing said front opening; a bulb assembly comprising a cylindrical socket containing a bulb, an annular member encircling said socket and including a radially outwardly extending stop flange and defining with said socket an annular groove diverging in direction away from said bulb, and a sealing mass in said groove seal-tightly encircling said socket, said bulb assembly being located in said reflector assembly with said flange abutting against said ledge rearwardly of the latter to properly position said bulb assembly; an annular sealing ring in said sleeve rearwardly of said flange; and removable securing means for holding said flange against said ledge and said sealing ring against said flange and comprising a further cylindrical sleeve fitting into said first sleeve rearwardly of said sealing ring.