GB2071410A

GB2071410A - Sealed Beam Lamp and Method of Manufacture

Info

Publication number: GB2071410A
Application number: GB8104220A
Authority: GB
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1980-03-10
Filing date: 1981-02-11
Publication date: 1981-09-16
Also published as: DE3107274A1; CA1147311A; JPS56138857A; NL8100884A

Abstract

A lamp 10 comprises lamp terminals 34, lens 14, light bulb 21 and reflector 12, the lens and reflector forming a sealed envelope containing the light bulb, and the bulb lead wires 30, 32 being secured directly to respective ends of the terminals positioned within the envelope and constituting a light source assembly 16. The terminals extend through openings 29 formed at the rear of the reflector, the openings being large enough to allow adjustment of the light source assembly with respect to the reflector by manipulating the terminals from the rear of and outside the lamp envelope thus simultaneously compensating for variations between bulbs, reflectors and lenses. The lamp is aimed simultaneously with adjustment of said light source assembly, pads 17 defining an aiming plane. Once adjustment is complete, the light source assembly is secured in position relative to the reflector by means of adhesive 43 located in said openings and around said terminals. The defined construction eliminates the need for mounting and sealing ferrules and separate lead-in wires between the terminals and the bulb. <IMAGE>

Description

SPECIFICATION Sealed Beam Lamp and Method of Manufacture The present invention relates to a sealed beam lamp construction which eliminates the need for grinding aiming points by enabling aiming of the lamp to be carried out simultaneously with adjustment of the light source filaments with respect to the reflector while minimizing the number of parts used in the manufacture of the lamp and compensating for variations between lamp component parts.

Sealed beam tungsten-halogen lamps are currently avaiiable in which the bulb filament support wires are secured to lead-in wires which are in turn brazed or soldered into electrically conducting ferrules sealed on the glass ferrule bosses formed on the rear of the reflector, electrical terminals being soldered on the outer end of each of the ferrules, all as shown in U.S.

patent 4,146,812 issued March 27, 1979 to Gagnon. In assembly of the patented lamp, the bulb is manipulated in the reflector by means of the lead-in support wires extending through the reflector to establish its proper location with respect to the reflector after which the lead-in support wires are soldered to the ferrules and terminals and the excess length of support wire is clipped off. The aim of the lamp is established by means of the conventional lens aiming pads.

The U.S. patent to Plagge et al 3,010,045 issued November 21, 1 961 discloses a sealed beam lamp in which a sealing disc is used to block flow of sealing plastic into the reflector envelope.

The present invention is designed to enable the simultaneous aim of the lamp and adjustment of the bulb filament with respect to the reflector in three directional axes mutually at right angles to one another and referred to hereinafter as the X Y-Z directional axes so as to obtain a desired optical pattern from the lamp during the manufacture thereof, the structure of the lamp lending itself to high production processing by minimizing the number of parts, by eliminating the need for grinding the aiming pads, and by the manipulation of the light bulb, e.g., a tungstenhalogen bulb, from the rear of and outside the reflector-lens envelope to simultaneously compensate for the variations between reflectors, light sources, and lenses.

A sealed beam lamp according to the invention has a minimum number of parts consisting of lamp terminals, a lens, light bulb, and reflector, said lens being positioned on and sealed to the front of a flange formed on the open front end of said reflector to form a sealed envelope containing the light bulb as a light source, said light source being supported by and having lead wires which are electrically connected to respective ends of said terminals positioned within the envelope and constituting a light source assembly, said terminals extending through openings formed at the rear of the reflector, the openings being large enough to allow adjustment of the light source assembly with respect to the reflector in the X-Y-Z directional axes to obtain optimum location of said light source with respect to said reflector, the terminals of said light source being secured in the respective openings in the reflector by adhesive positioned in one or more recesses in said reflector, said sealed beam lamp being further characterized by unground aiming pads on the lens face which are as short as possible while being long enough to enable the establishment of an aiming plane, means being provided on the outer surface of said reflector to enable seating of said sealed beam lamp in a vehicle in an oriented position, the aim of the lamp being achieved at the same time said light source assembly is positioned with respect to said reflector.

Optimum location of the light source with respect to the reflector is achieved by manipuiating the light source assembly from the rear of and outside the lamp envelope thus simultaneously compensating for variations between light sources, reflectors and lenses, the light source assembly being then sealed in the reflector by sealing adhesive, e.g., glass adhesive, epoxy or other resin, which is applied about the terminals in the reflector.

The invention and how it may be performed are hereinafter particularly described with reference to the accompanying drawings in which Figure 1 is a partially sectioned top view of a sealed beam headlamp made in accordance with our invention; Figure 2 is a broken-away view similar to Figure 1 showing modifications of the light source assembly and the reflector construction; Figure 3 is a view similar to Figure 2 showing further modifications of the reflector and light source assembly construction; and Figure 4 is a view similar to Figure 2 showing the preferred embodiment of the reflector and light source assembly construction.

Referring now to Figure 1 , there is shown a rectangular sealed beam lamp 10 of the type commonly used for motor vehicle headlamps. The lamp 10 comprises a reflector 12 and a lens 14 enclosing a light source assembly 16. The reflector 12 and lens 14 may be formed of either glass or a plastics material as is well known in the lamp forming art. Also, the reflector 12 has a parabolic reflective surface 1 8 with a bright metallic deposit for directional control of the light rays emitted by a filament 20. Reflector 12 is provided with corner seating pads 11 on the rear surface of a reflector sealing flange 9. As shown, these pads are of limited height and mass, and, since they are not formed on the body portion of the reflector, points of thermal stress inherent in the usual design are eliminated.Also, instead of forming one of the pads 11 with a substantially larger area than the remaining pads for lamp orienting purposes, we prefer to use at least one orienting tang 8 formed off-center on the rear surface of the reflector. The lens 14 includes suitable optical flutes and facets for imparting directional control to light rays projected by the reflector 12. Aiming pads 17 are provided on the front surface and are of significantly shorter height than the pads normally used. The pads 1 7 are formed as short as possible while being long enough to enable the establishment of an aiming plane since there is no need for grinding off their ends.The aim of the lamp is achieved at the same time the light assembly 1 6 is oriented with respect to the reflector 12, the lamp envelope being oriented to obtain the desired aim by use of known equipment gauged to the lens aiming pads 17. This allows the height of the aiming pads to be reduced thus significantly reducing the number of rejects due to breaking during grinding and handling.

The lens 14 and the reflector 12 are joined at their peripheral flanges to form a leak-proof seal.

As shown, a ridge or lip 15 is formed on the peripheral flange 9 of the reflector, alternatively on the lens flange 13, and a seal is obtained by any suitable means such as ultrasonic welding, flame sealing or use of adhesive, e.g., an epoxy or polyester based adhesive, or glass adhesive.

Structurally, any suitable mating design may be used, e.g., the lip-flange design shown or a lipchannel design such as that shown in U.S. patent 3,625,796.

The light source assembly 1 6 is structurally joined to the reflector 12 by means of terminals 27 sealed on the rear of the reflector as shown in the drawings. The inner surfaces of the assembled components define a sealed lamp envelope having a controlled environment of inert and/or dry gas.

The light source assembly 1 6 consists of filament 20, shown in Figure 1 as contained in a bulb 21, e.g., a tungsten-halogen bulb, a pair of terminals 27, and a pair of lead wires 30, 32 connected to the ends of filament 20 and extending through a pinch portion 22 of bulb 21 for electrical connection with their respective terminals 27.

As shown in Figure 1, the terminals 27 are formed with an outer end blade portion 34 adapted for interconnection with a suitable power source, the inner end being provided with a plurality of tabs 36 and 37 to which lead wires 30.

and 32 are respectively crimped for electrical and mechanical interconnection. Other suitable means such as spot welding and the use of a separate support wire 31, support straps, tabs or projections in the bulb pinch portion may be used.

While a single filament bulb is shown, it should be understood that a two filament bulb is well known in the art may also be used, the third wire being electrically connected to a third terminal sealed within the reflector in the same manner as described herein.

As shown in the drawings, the central portion of reflector 12 is formed to provide a plurality of openings 29 through which the outer ends 34 of terminals 27 extend. Tabs 35 may be formed on the terminals to prevent them from falling through the openings once they are passed therethrough.

As shown in Figure 1, the rear of the reflector through which the terminals 27 are passed is thickened and the openings 29 are provided in concavities or recesses formed in both the inner and outer reflector surfaces with their bottom surfaces closely spaced apart to form a relatively thin section 33 in the reflector 12 about the terminals to enable a rocking movement of the terminals during assembly. The reflector 12 is also provided with evacuating means, shown as a sealed-off evacuating tube 26. As shown, the light source assembly 1 6 is supported in reflector 12 by a sealing adhesive 43, the correct positioning of bulb 21 and its filament 20 for obtaining the desired light pattern and aim being obtained in the manner described herein.

The width of the section 33 closely surrounding the terminals 27 is maintained sufficiently thin to enable rocking movement of the terminals for ready adjustment of the filament 20 with respect to the reflector 12 in the updown (Y-Y) and sideways (X-X) directions, adjustment in the longitudinal or front-rear (Z-Z) direction being achieved by the front-rear movement of the terminals 27 through the openings 29. While the adjustment of the light source assembly may be accomplished before or after sealing the lens 14 on the face of reflector 12 during assembly in a machine of the type known in the art, we prefer to accomplish adjustment after sealing the lens on the reflector.

Upon achieving the desired lighting pattern, the adhesive is activated, e.g., by ultraviolet light, heat, or other suitable means, and the position of the light source assembly 1 6 is fixed with respect to reflector 12.

In the assembly of the lamp shown in Figure 1 in accordance with our invention, the terminals 27 are arranged to maintain the specified positioning for each terminal, this being accomplished using mechanisms well known in the art and forming no part of our invention. The bulb 21 is then electrically connected to and mechanically supported on terminals 27 by securing the lead wires 30 and 32 of the bulb to tabs 36 and 37 to form light source assembly 16.

Assembly 1 6 is positioned in reflector 12 with blade portions 34 extending through the openings 29, this combination being then loaded into an assembly fixture also no part of our invention. The lens 14 is then positioned on the reflector 12 and a sealing bond is effected between the two in any suitable manner e.g., flame sealing or by using the adhesive 43 as previously described. The sealing adhesive 43 is then dispensed in predetermined amount into the recesses about opening 29 on the surface of reflector 12 and about terminal portions 34. As noted above, any suitable adhesive may be used, but we prefer to use an ultraviolet light-activated polyester based adhesive such as Loctite 352 (modified)(R) or LO-727 (Fl) available from Loctite Corporation, Newington, Connecticut. Also, while the sequence is described as dispensing adhesive prior to adjustment of the bulb position, this may be performed after such adjustment and reference to the one is intended to include the other. Bulb 21 is lit and the light source assembly 16 is moved by the assembly fixture in the X-Y-Z directions. The proper adjustment is determined by optical sensors when the predetermined optical optimum position producing the desired lighting pattern is achieved. The lamp is also aimed at the same time in accordance with applicable lighting standards. The adjusted assembly is then subjected to the activating or setting ultraviolet light to effect the adhesive cure.

Since all component parts affecting the optical pattern are in place at the time of adjustment, this operation compensates for all variations between the optical components with resultant cost and quality benefits and is preferred. As described above, any suitable sealing technique may be used. The sealed envelope formed by the lens 14 and reflector 12 is then exhausted and/or flushed through the fill opening, tube 26, a replacement fill of inert and/or dry gas being provided, after which the tube is sealed.

While we have described our invention in terms of the embodiment shown in Figure 1, modifications of this design are shown in Figures 2, 3 and 4.

In Figure 2 the reflector 12' is formed with a cup-shaped recess 40 at the rear thereof and in its outer surface. The openings 29' through which the blade portions 34' of terminals 27' extend are within the cup-shaped recess 40 and are large enough to permit adjustment of the light source assembly 16' in the up-down and sideway directions for obtaining the aim of the lamp and the optimum optical positioning with respect to reflector 12'. The adhesive 43, as previously described, is used to fix the position of assembly 16' in the adjusted position. Holes 34a are shown in terminal blade portions 34' to improve the anchoring of the terminals in the cement. A retainer shield 42 is positioned in recess portion 40 to fit closely about terminal blade portions 34' to prevent flow of, adhesive 43 into the reflector.

Shield 42 may alternatively be positioned on the inner surface of reflector 12' or may be omitted if appropriate.

Also in Figure 2, the terminals 27' are shown as having their inner ends formed by bending to provide clips 38 and 39, the latter shown broken away, for supporting the pinch portion of bulb 21'. The inner end of each terminal 27' is provided with spaced holes 44 in which support wires 46 and lead wires 48 are positioned and securely attached, e.g., spot welded, soldered, brazed and/or clamped to form good support and electrical interconnections. The same method of assembly is used as previously described for the embodiment of Figure 1 and all other features of the lamp are as previously described.

Figure 3 shows a further embodiment of our invention, similar to that of Figure 2, wherein a cup-shaped recess portion 40' is formed in the inner surface of reflector 12". Also, the shield 42 is shown on the outer surface of reflector 12" but may be alternatively located on the inner surface in portion 40'. The bulb 21 is electrically interconnected with and supported by the terminals 27" by means of tabs 36 to which the lead wires 30 and 32 are spot welded or brazed.

The method of assembly is the same as previously described and other features of the lamp are as previously described.

Figure 4 shows the preferred embodiment of our invention wherein the rear of the reflector 12"' through which the terminals 27"' are passed is thickened and the opening 29" are provided in an annular recess 45, or in separate recesses formed about each opening, the openings conforming to the shape of the terminals passing therethrough and being large enough to permit adjustment of the light source assembly 16" in the X, Y, and Z directions as described. The adhesive 43 is positioned in the recess 45 about terminals 27"' to achieve a seal in openings 29". The bulb 21 is electrically interconnected with and supported by the inner end of terminals 27"' which may be crimped and/or welded about the end of lead wires 30 and 32. This terminal -- lead-in wire configuration is preferred as being most ecomomical and reliable.

Evacuation or flushing and refill of the lamp envelope is achieved through fill opening 47, in the rear of the reflector, this being plugged by a sealing adhesive such as that described herein.

The method of assembly is the same as previously described and all other lamp features are as previously described.

Accordingly, the invention provides a sealed beam lamp having a minimum number of parts in which the light bulb may be readily positioned from the rear of the reflector to locate the light source with respect to the reflector and the lens so as to obtain the desired pattern of light therefrom.

A lamp design according to the invention enables the use of simple production processing to obtain a sealed beam lamp having a light bulb positioned to locate the filaments with respect to the reflector to obtain the optimum light patten, the aim of the lamp being achieved without the need for grinding the conventional aiming pads while compensating for variations between individual reflector, lens and light source parts.

The weight of the lamp is also decreased and thermal stress points are removed by eliminating the conventional elongated corner seating pads.

From the foregoing, it is apparent that we have provided a lamp structure having a minimum number of parts as well as a method of assembly eliminating all need for preorientation of the lamp filaments with respect to one or more indexing surfaces on one or more parts of the lamp structure. instead, the structure of our invention permits the simple and simultaneous aim and adjustment of the light source assembly in all three directions during the assembly operation and after the sealing of the lens on the reflector to thus compensate for any variations between the parts making up the lamp assembly. Changes in the design and method will be apparent to those skilled in the art such as substitution of materials, variations in reflector-iens peripheral flange mating design, bulb construction, bulb to terminal assembly, terminal variations and various terminal-refiector design combinations, all within the scope of our invention as defined by the claims which follow.

Claims

1. A sealed beam lamp having a minimum number of parts consisting of lamp terminals, a lens, light bulb and reflector, said lens being positioned on and sealed to the front of a flange formed on the open front end of said reflector to form a sealed envelope containing the light bulb as a light source, said light source being supported by and having lead wires which are electrically connected to respective ends of said terminals positioned within the envelope and constituting a light source assembly, said terminals extending through openings formed at the rear of the reflector, the openings being large enough to allow adjustment of the light source assembly with respect to the reflector in the X Y-Z directional axes to obtain optimum location of said light source with respect to said reflector, the terminals of said light source assembly being secured in the respective opening in the reflector by adhesive positioned in one or more recesses in said reflector, said sealed beam lamp being further characterized by unground aiming pads on the lens face which are short as possible while being long enough to enable the establishment of an aiming plane, means being provided on the outer surface of said reflector to enable seating of said sealed beam lamp in a vehicle in an oriented position, the aim of the lamp being achieved at the same time said light source assembly is positioned with respect to said reflector.

2. A sealed beam lamp according to claim 1, in which said recess in said reflector is a cup-shaped portion surrounding said terminals.

3. A sealed beam lamp according to claim 1, in which said recess in said reflector is an annular recess, in the base of which said openings are located.

4. A sealed beam lamp according to claim 1,2 or 3, in which said means on the outer surface of said reflector consists of seating pads positioned on the rear surface of said flange with either one of said pads being specially formed to serve as an orienting member or with a separate orienting tang formed on said reflector outer surface.

5. A method of manufacturing a sealed beam lamp according to any one of the preceding claims, comprising the steps of arranging the lamp terminals to obtain a desired positioning therebetween, connecting the light bulb lead wires to the respective ends of said terminals to establish good mechanical support and electrical contact therebetween to form said light source assembly, positioning said light source assembly in said reflector having a plurality of openings in the rear thereof through which said terminals extend, dispensing a predetermined amount of adhesive onto said reflector about said terminals extending therethrough, lighting said light bulb and moving said light source assembly in the updown, sideways and forward-backwards directions relative to said reflector to position said light bulb relative to said reflector so as to obtain a predetermined optical optimum position producing the desired lighting pattern while simultaneously establishing the aim of the said lamp, activating said adhesive to fix said light source assembly in the established relative position, said sealed envelope being formed between said lens and said reflector by positioning and sealing said lens on the front end of said reflector, evacuating and/or flushing said envelope and filling said envelope with an inert and/or dry gas through a fill opening formed in said lamp envelope, and then sealing the fill opening.

6. A method of manufacturing a sealed beam lamp according to claim 5, in which said lens is sealed on said reflector prior to positioning said light bulb relative to said reflector.

7. A sealed beam lamp substantially as hereinbefore particularly described and as shown in Figure 1 of the accompanying drawings.

8. A sealed beam lamp substantially as hereinbefore particularly described and as shown in Figure 1, as modified by Figure 2, of the accompanying drawings.

9. A sealed beam lamp substantially as hereinbefore particularly described and as shown in Figure 1, as modified by Figure 3, of the accompanying drawings.

10. A sealed beam lamp substantially as hereinbefore particularly described and as shown in Figure 1, as modified by Figure 4, of the accompanying drawings.