US3553520A

US3553520A - High intensity driving lamps particularly for road vehicles

Info

Publication number: US3553520A
Application number: US750166A
Authority: US
Inventors: Harris Vernon Hicks
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1967-08-16
Filing date: 1968-08-05
Publication date: 1971-01-05
Anticipated expiration: 1988-01-05
Also published as: NL6811614A; BE719623A; DE1797055B2; ES357560A1; DE1797055A1; SE354704B; GB1221946A

Abstract

A sealed beam lamp includes a reflector, having a lens secured thereto and defining therewith a sealed enclosure. A quartz iodine or equivalent high intensity bulb is located within said enclosure, and is carried by the reflector, and a light shield for preventing light from the bulb issuing from the lamp, without first being reflected from the reflector, is associated with the bulb.

Description

United States Patent IIIGII INTENSITY DRIVING LAMPS PARTICULARLY FOR ROAD VEHICLES 8 Claims, 5 Drawing Figs.

u.s. c1. 313/113, 240/41.35,240/41.4,313/117 FieldofSearch 313/113- [56] References Cited UNITED STATES PATENTS 1,439,313 12/1922 Landis 240/46.55 1,772,175 8/1930 Arbuckle 240/4125 1,927,285 9/1933 Hurrell et al 240/4655 3,107,866 10/1963 Nowak 240/4125 3,445,646 5/1969 Brooks et al 240/41.35X

Primary Examiner-James W. Lawrence Assistant Examiner-David OReilly Attorney-Holman & Stern 1113 j J! I 147 in FIG. 1,

all drawn to the same scale.

HIGH INTENSITY DRIVING LAMPS PARTICULARLY FOR ROAD VEHICLES This invention relates to sealed beam lamps for road vehicles.

Generally, the present invention relatesto a high intensity driving lamp comprising a reflector and a lens secured to the reflector around its periphery for defining a sealed enclosure therebetween, a quartz halogen bulb fixedly secured to the reflector within the enclosure, connecting leads for the bulb extending within the enclosure, said enclosure having an at mosphere which is nonoxidizing with respect to said connecting leads.

One example of the invention is illustrated in the accompanying drawings wherein:

v.FIG. l is a sectional view of a sealed beam lamp for a road vehicle,

FIG. 2 is a sectional view on the line 2-2 in FIG. 1,

FIG. 3 is a perspective view of the quartz iodine bulb shown FIG. 4 is a perspective view of a light shield shown in FIG. 1 and FIG. 5 is a perspective view of the ceramic bulb support shown in FIG. 1, it being appreciated that FIGS. 1 to 5 are not Referring to the drawings, the lamp ncludesan outer casing 11 adapted at 12 to be secured to a road vehicle. Secured within the casing 11, by means of a clamping ring 13, is a sealed beam lamp unit 14, including a paraboloidal reflector 15 and an integral lens 16, the sealed enclosure defined by the lens 16 and the reflector 15 being filled with an inert atmosphere. The reflector 15 is moulded in glass and secured to the outer surface thereof is a pair of conductive blade terminals 17, 18. Extending through sealed pinches 19, 21 in the reflector 15, adjacent the terminals 17, 18 is a pair of stiff conductive leads 22, 23 electrically connected respectively to the terminals 17, 18. The production of the pinches 19, 21 results in local distortion of the inner surface of the reflector adjacent the pinches and when the inner surface of the reflector is aluminized to render it highly reflective the area of the inner surface of the reflector 15 adjacent the pinches 19, 21 is masked so that the distorted areas of the reflector are not aluminized. Thus the amount of light which will. be scattered by the distorted areas of the reflector 15 is minimized.

The leads 22, 23 extend forwardly from the reflector, for a short distance, parallel with the axis of the reflector and are then, bent through 90 to extend towards one another for a further short distance.

Extending parallel with the axis of the reflector are a further pair of

conductive leads

24, 25 which are welded at one end to the free ends of the leads 22, 23 respectively. The leads 24, 25

extend through corresponding parallel bores 27 in a ceramic bulb support member 26. The member 26 comprises a rectangular block 28 of ceramic material having a pair of parallel fingers 29 integral therewith and extending from one end thereof. The end of the block 28 remote from the fingers 29 is formed with a transverse groove 31 in which the bent portions of the leads 22, 23 lie. The bores 27 extend from the base of the groove 31 and terminate between the fingers 29.

Engaged with the member 26 is a quartz iodine bulb 32. The bulb 32 comprises a generally cylindrical quartz envelope 33 housing a tungsten filament 34. Thebase of the bulb 32 is formed by a pinch 35 and enclosed in thickened edges 36 of the pinch 35 are a pair of

conductive ribbons

37, 38 which at one end are interconnected by the filament 34 and which at their other ends are connected to the

leads

24, 25 respectively so that an electrical circuit between the terminals 17, I8 is completed through the filament 34. Between the edges 36 of the base of the bulb is an integral web 39 and the bulb 32 is engaged with the member 26 by inserting the web 39 between the fingers 29 of the member 26 until the free end of the web 39 engages the block 28 of the member 26, the member 26 serving to minimize flexure of the

leads

22, 23, 24, 25 in use and thereby to minimize movement of the bulb relative to the reflector.

Trapped between the base of the bulb'32 and the member 26 is a rear light shield 41 which includes a pair of side portions 42 which extend parallel with the axis of the reflector l5 and which masks the edges 36 of the pinch 35 and the deformed parts of the envelope 33 adjacent the edges 36, and a top portion 43. The portion 43 includes apart 430 which extends at right angles to the axis of the reflector l5 and integral with the part 43a is a further part 43b which extends parallel with the axis of the reflector. The portion 43 masks the deformed part of the envelope 33 adjacent the web 39 which is uppermost in use.

Extending parallel with the leads 22, 23 from a third pinch 44 in the reflector 15 is a rigid rod 45 which at its end remote from the reflector 15 carries a front light shield 46. The shield 46 is in the form of a cup-shaped member which encloses the forward end of the envelope 33. The shield 46 includes a resilient metal strip 47 which engages the envelope 33 at a pair of spaced points and the shield 46 itself engages the envelope at a third point which is the lowermost point of the envelope 33 in use, so that the envelope is held against movements in directions transverse to the axis of the reflector 15 by the shield 46 and the rod 45, in addition to member 26. The manufacture of the envelope 33 involves the formation of a pinch 33a at the end of the envelope 33 remote from the reflector 15, the pinch 33a being enclosed within the shield 46. The edge of the shield 46 lies on the surface of a cone having its apex at the center of the filament 34 and its base at the front edge of the reflector so that ny any light from the filament 34 which is travelling in a direction such that it would pass directly through the lens 16, without first being reflected from the reflector 15 is blocked by the shield 46.

In use when the lamp is assembled the

leads

24, 25 are welded to the ribbons 37 38 of the bulb 32 and the rear shield 41 is engaged with the base of the bulb 32, a pair of tags 42a integral with the side portions 42 of the shield 41 being deformed to grip the web 39 of the bulb 32. The bulb 32 and shield 41 are then engaged between the fingers 29 of the member 26 with the

leads

24, 25 extending through the bores 27 of the member 26 into the groove 31. The ends of the

leads

24, 25 are then welded to the ends of the leads 22, 23 respectively so that the bent portion leads 22, 23 he in the groove 31. The shield 46 is then engaged with the erivelope33 of the bulb 32 and is moved to its correct position, a tag 47a integral with the strip 47 of the shield 41 being welded to the rod 45 to support the bulb 32 firmly in position relative to the reflector 15.

It is important when using a high intensity lamp that light from the lamp is directed down onto the road and that a minimal amount of light is scattered upwardly from the lamp. It will be appreciated, that the pinch 33a, if it were not masked by the shield 41, would scatter light from the filament 34 in all directions. Moreover the deformed areas of the envelope 33 around the pinch 35, and the pinch 35 itself, refract the light from the filament and so constitute light sources themselves. The additional light sources constituted by the pinch 35 and its surrounding part of the envelope 35 are behind the focal point of the reflector l5 and so would produce a divergent beam issuing from the lamp. However the side portions 42 and the top portion 43 of the rear shield 4] block all of the light which would produce such a divergent beam with exception of that part of the light issuing from the lowermost part of the envelope 33 which would result in a divergent beam directed downwardly onto the road. Furthermore, the portion 43 of the shield 41 is also positioned to block any light which would be reflected from the deformed area of the reflector 15 around the pinch 44, since the area around the pinch 44 unlike the areas around the similar pinches 19, 21 is aluminized when the reflector is manufactured and so is highly reflective. The area around the pinch 44 is not masked with the areas around the pinches 19, 21 during the aluminizing process, since it has been found more convenient to utilize the shield 41 to prevent reflection from the area around the'pinch 44.

In conventional lamps employing quartz iodine or equivalent high intensity bulbs, unless great care is taken in design to avoid excessively high temperatures near the pinch 35 there is a possibility of early failure of the bulb because of gradual-oxidation of the

ribbons

37, 38. This oxidation causes the

ribbons

37, 38 to swell and theswelling eventually cracks the pinch 35, allowing air to enter the bulb, whereupon the bulb burns out. Since the bulb 32 of the present construction is housed in an enclosure containing an inert atmosphere, the ribbons 38, 39 cannot oxidize, so this hazard does not arise.

It will be appreciated that the light shield 46, and in particular the light shield 41, are so constructed that they do not scatter the light which they are intended to block in directions which would have deleterious effects on the accurate high intensity beam issuing from the lamps.

lclaim:

l. A high intensity driving lamp comprising a reflector and a lens secured to the reflector around its periphery for defining a sealed enclosure therebetweema quartz halogen bulb fixedly secured to the reflector within the enclosure, connecting leads for the bulb extending within the enclosure, said enclosure having an atmosphere which is nonoxidizing with respect to said connecting leads, and a light shield associated with the bulb for preventing light which has not first been reflected from the reflector issuing from the lamp.

2. The high intensity lamp as claimed in claim 1 in which said light shield is secured to the reflector and is engaged with the bulb and serves to support the bulb.-

3. The high intensity lamp as claimed in claim 1 in which said shield includes a cuplike portion enclosing the forward end of the bulb, with the free edge of said cuplike portion and the periphery of the reflector lying upon the surface of an imaginary cone, the apex of the imaginary cone being at the center of the bulb filament whereby the light shield prevents light from the bulb which has not first been reflected from the reflector issuing from the lamp.

4. The high intensity lamp as claimed in claim 1 in which the areas of the reflector through which said connecting leadsextend into the enclosure are substantially non'reflective. g

5. The high intensity lamp as claimed inclaim 1 further including a second light shield positioned with respect to the bulb to prevent those light rays which have been reflected by the bulb at the base thereof and which would be reflected by the reflector to issue from the lamp upwardly relative to the axis of the reflector, from striking the reflector.

6. The high intensity lamp as claimed in claim 5 in which the portions of said second light shield which block light from'the portion of the bulb at the base thereof are so positioned.that the refracted rays are not scattered by the shield in directions having a deleterious effect on the beam produced by the lamp.

7. The high intensity lamp as claimed in claim I in which said connecting leads are engaged with a rigid heat resistant member serving to minimize flexure of the leads.

8. The high intensity lamp as claimed in claim 7 further including a second light shield positioned with respect to the bulb to prevent those light rays which have been refracted by the portion of the bulb at the base of the bulb and which would be reflected by the reflector to issue from the lamp upwardly relative to the reflector in use, from striking-the reflector and said second shield being engaged with said heatresistant member.

Claims

1. A high intensity driving lamp comprising a reflector and a lens secured to the reflector around its periphery for defining a sealed enclosure therebetween, a quartz halogen bulb fixedly secured to the reflector within the enclosure, connecting leads for the bulb extending within the enclosure, said enclosure having an atmosphere which is nonoxidizing with respect to said connecting leads, and a light shield associated with the bulb for preventing light which has not first been reflected from the reflector issuing from the lamp.

2. The high intensity lamp as claimed in claim 1 in which said light shield is secured to the reflector and is engaged with the bulb and serves to support the bulb.

4. The high intensity lamp as claimed in claim 1 in which the areas of the reflector through which said connecting leads extend into the enclosure are substantially nonreflective.

5. The high intensity lamp as claimed in claim 1 further including a second light shield positioned with respect to the bulb to prevent those light rays which have been reflected by the bulb at the base thereof and which would be reflected by the reflector to issue from the lamp upwardly relative to the axis of the rEflector, from striking the reflector.

6. The high intensity lamp as claimed in claim 5 in which the portions of said second light shield which block light from the portion of the bulb at the base thereof are so positioned that the refracted rays are not scattered by the shield in directions having a deleterious effect on the beam produced by the lamp.

7. The high intensity lamp as claimed in claim 1 in which said connecting leads are engaged with a rigid heat resistant member serving to minimize flexure of the leads.

8. The high intensity lamp as claimed in claim 7 further including a second light shield positioned with respect to the bulb to prevent those light rays which have been refracted by the portion of the bulb at the base of the bulb and which would be reflected by the reflector to issue from the lamp upwardly relative to the reflector in use, from striking the reflector and said second shield being engaged with said heat resistant member.