US3904909A

US3904909A - Pinch-sealed electric lamps

Info

Publication number: US3904909A
Application number: US411698A
Authority: US
Inventors: Arthur Samuel Vause
Original assignee: Thorn Electrical Industries Ltd
Current assignee: Thorn Electrical Industries Ltd
Priority date: 1972-11-09
Filing date: 1973-11-01
Publication date: 1975-09-09
Anticipated expiration: 1992-09-09
Also published as: GB1447764A; DE2355637C3; CA998421A; DE2355637A1; IT999324B; DE2355637B2; FR2206580A1; FR2206580B1; NL7315157A

Abstract

A filament or discharge lamp with a pinch seal at an end of the envelope has shaped metal members pressed into the external faces of the pinch to provide positive mechanical engagement of the material of the pinch with the metal members. The metal members are thereby located with respect to the internal components of the lamp and serve as supports for positioning the lamp in an optical system such as an automobile headlamp.

Description

United States Patent Vause Sept. 9, 1975 [5 PINCH-SEALED ELECTRIC LANIPS 2,864,025 12/1958 Foote et a1 313/274 X 2,999,180 9/1961 Howles ct a1. 313/318 [75] Inventor: Arthur Samuel Vause, London 3,265,923 8 1966 Preziosi et a1. 313/318 England 3,286,088 11/1966 Ahroni 313/318 x 3,320,466 5/1967 Ayres et a1 313/318 [73] Asslgnee' g 1 dlndustr'es 3,360,765 12/1967 Strangles et a1. 313/318 x on 3,441,778 4/1969 Deiss 313/318 [22] Fil d; No 1, 1973 3,469,140 9/1969 Bottone ct a1. 313/318 3,602,761 8/1971 Kimball 313/274 [21] Appl. No.: 411,698

Primary Examiner-Saxfield Chatmon, J r. 30 Foreign Application priority Data Attorney, Agent, or FirmRobert F. OConnell Nov. 9, 1972 United Kingdom 51819/72 [57] ABSTRACT 52 us. c1. 313/318; 29/251; 174/5052; A filament or discharge lamp with a pinch sea] at an 313/274; 339/102 L; 339/198 E end of the envelope has shaped metal members [51] Int. Cl H01 j 5/48; H0 1 j 5/50 p d o the external faces of the pinch to provide [58] Field of Search 313/318, 1 13, 271, 274; positive mechanical engagement of the material of the 174/506], 50,62, 50,63, 50,64; 339/198 E, pinch with the metal members The metal members 275 R, 275 T, 102 L; 29/251 are thereby located with respect to the internal components of the lamp and serve as supports for position- [56] References Cited ing the lamp in an optical system such as an automo- UNITED STATES PATENTS blle headlamp.

2,730,689 1/1956 Lamb at al 313/318 X 8 Claims, 8 Drawing Figures PINCH-SEALED ELECTRIC LAMPS The present invention relates to the manufacture of electric lamps having light sources contained in hermetically closed envelopes the envelopes having pinch seals. The light sources can be incandescent filaments or are discharges.

The principal aim of this invention is the provision of inexpensive means which assist in establishing accurate orientation of a light source relative to optical components with which it may be associated in service. Examples of such optical components include reflectors, shields and gates.

In accordance with the present invention there is provided an electric lamp having an envelope with a pinch seal and shaped metal members secured to the external faces of the pinch seal'by pressing of parts of the metal members into the material of the pinch seal whereby there is mechanical co-operation of the said material with the metal members to hold the metal members in a definite position relative to the internal components of the lamp.

Also, in accordance with the invention, a method of making a lamp having a vitreous envelope includes the steps of heating an end portion of the envelope until it is plastically deformable and thereafter pressing the end part upon itself to define a pinch seal, shaped metal members being applied to the pinch seal such that parts of the members become embedded therein with the remainder of each member exposed.

The shaped metal members may be provided with discrete projecting tangs to be forced into the press seal while the latter is in a plastic state. Instead of discrete tangs, the shaped metal members can have turned-over edges which are forced into the press seal. Alternatively, or in addition to the tangs or turned-over edges, the metal members can be punched or pierced to form holes preferably having rough or ragged edges which project outwardly from the members. With such a con struction, the ragged projecting edges can be embedded in the pinch-seal while the vitreous material of the seal can extrude into the holes. During the pressing operation, the extruding material can mushroom as it emerges from the holes, thereby formly securing the metal member to the pinch-seal. Conveniently, movable jaws which are used to produce the pinch seal are adapted to hold the shaped metal members so that the latter can be applied to the envelope simultaneously with the formation of the pinch seal. In this way, subsequent rc-heating of a previously-formed pinch seal is rendered entirely unnecessary.

The shaped metal members which are secured to the pinch-seal may conveniently enable a lamp cap to be fastened to the envelope. In this way, the use of cements can be avoided thereby making temperatureresisting anchorage of the cap possible.

One type of lamp embodying the invention is intended to be mounted in a sealed-beam lighting unit. In this case, the shaped metal members are arranged to act as supports to be attached, say, to the rear reflector element of the unit. The supports may be in the form of brackets having leg portions, which extend towards the said element, and foot portions which are secured thereto. The shape and dimensions of the metal bracket member are chosen to ensure that the lamp adopts a correct orientation relative to the focal points and optical axis of the lighting unit when it is being mounted on the said element.

The lamp need not, of course, be intended for use in a sealed beam unit. Instead, it can be a replaceable plug-in bulb for usewith a socket which is part of optical apparatus e.g. an image projector, a spot or floodlight, or a vehicle headlamp. In such apparatus, the socket would already be in a proper orientation with respect to a reflector, gate and the like. It is then necessary to ensure that the lamp-bulb will always seat accurately in the socket. The exposed part of each shaped metal member may, in one instance, be in the form of a strip designed to mate with accomodating keying structures such as recesses in the socket.

For some applications, it may advantageous if lead-in conductors which enter the lamp through the pinchseal are electrically connected to the shaped metal members. The latter are relatively large, in comparison to the lead-in conductors, and can carry quite heavy currents. Also they can act as effective radiators, thereby dissipating heat energy and helping to keep the operating temperature of the pinch seal within acceptable limits.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

FIGS. 1 and 2 are two partial perspective views of a lamp primarily intended for installing in a sealed-beam lighting unit,

FIG. 3 is a partial side elevation of the lamp shown in FIGS. 1 and 2,

FIGS. 4, 5 and 6 are perspective, end and side elevations of a baseless electric lamp, only part of which is illustrated,

FIG. 7 is a side elevation of an H-2 type lamp embodying the invention, and

FIG. 8 is a side elevation partly in cross-section of a capped lamp embodying the invention.

The lamp partially shown in FIGS. 1 to 3 is intended to form one of the components of a sealed-beam unit. The remaining components, which include rear reflector and front lens elements are not illustrated. It is necessary, when making a sealed-beam unit, to be able to position the light source or lamp accurately relative to these, and possibly other elements such as gates.

To facilitate correct positioning of the lamp, it is provided with a plurality of shaped sheet metal members 10. The members 10 are in the form of brackets having leg portions 11 and foot portions 12. The feet 12 are apertured to allow the members 10 to be secured to the rear reflector element of a sealed-beam unit. The length of the legs 11 is such that they support the lamp clear of the rear reflector element with the lamp filament at a predetermined position, e.g. coincident with the focus of the reflector.

The apertures 13 permit the mounting of the feet 12 on accurately-located studs or similar formations on the rear reflector element. Our copending British patent application Ser. No. 44240/72, filed on Sept. 25, 1972' and entitled Sealed Beam Lamp Construction" envisages such a lamp mounting, and further details may be found therein. The members 10 are arranged to act as current carriers to the lamp and accordingly the said studs are designed to be connectable to an external electricity supply.

The lamp has a plurality of lead-in conductors 15 which extend through a pinch seal 16 from the exterior 3 of thelamp to. the,.in,terior .o f,.its vitreous envelopb 17,. The conductors 15 are each soldered-. ,brazed .or erimpeduto arespective legll'. f ,-Each-i rnember; 10 ha5s projectingportions 18 which are. embedded inthe pinfchsealj lb, the remainingparts of the members being exposed on the,surfaces, of the pinchaseal tld fl hc projectingportions-18 may bc formed b rolling: orbending edges of the-members ,10 inwa fd y j iAs sliown here, the portions; 18; are in .the formiof dQveTtaiIedtan-gs.

v r of-lighting. apparatus? use replaceable lampx bulbsgi'Often,.it'is necessary that thebulbs,eu,pon replacement; alw'ay's'adopt precisely 'thesame position relative, for example, to areflector. This'requires, .On the oneg hand, an accurately-locatedreceiving lamp soc et and, on the othcr ha nd, co-operatingmeans on the "s ockettand lamp-bulb which positively and accuratelylecatethe bulb within the socket. ;ElGSU-4 to 6 illustrate alamp-bulb which is provided withrsheet metal: members for this purpose. The membersr30are-again attached to ,the exterior of .a pinch-seal 531 formed at OnGsfiDIldOfithC lamp envelope 32. The members 30 are elongated strips intended to mate with keying grooves of an associated socket. The longedges 31of' the members 30 are turned, inwardly and embedded in the pinch seal 32. Lead-inconductors 35.aresealed into-the envelopc33 by the pinch seal 32, theirends being connected to the members 30. The connections are made by suitable means such as soldering;-lwel,ding o'r crimping the members-30 about the conductors 35. .The members30 have the advantage that, being large relative to;the conductors 35, they are, easily coupled with mating contacts within the associated socket. Theirs-ize facilitates efficient coupling withthe mating contacts so that they are suitable for. high currentzloadlng t l. "'3 F1; When manufacturing the illustrated lamps, internal eomponentssuch as filamentsand disc harge e'lectnodes are attached toappropriate mounts to-which the leadin conductors. l5, and 35aresecured. The mounts are then installed, through-initially open ends of the envel- Opes-1:7 ,3-3. Thereafter, the-ends of

theenvelopes

17,33 atek heated to, -soften the vitreous material, whereupon the ends-are closed upon themselves, by pinch jaws to form the pinch seals. 16,32. l

A t;,,the.samctime as forming thepinch scals.l6,3 2, the .

members

10,30. are attached'to their envelopes. The ipinehiljayvsa'rc arranged to carry the

members

10,30, with their projections18,31-already preformed;

and 'to force the projections intothc softened vitreous material. l-t-isnot essentialto attach the

members

10,30

atthlesamefltimmas forming the pinch seals 16,32, however If the members I are subsequently attached,

though, the pinch seals 16,32 may need reheating to render. them soft enough to accept the projections ,-.EIG. .7 showsga tungsten-halogen lamp'em'bodying the invention for use in automobile headlamps. The lamp 40. has'a pinch-seal 41. through which extend :leads'42 to. azfilame'nt 43. The pinch-seal, 41 is flattened inlthe planez ofthe drawingandto its opposite facesitwo members ;44,45 "are seeurcd to; 3 the. material. of -.the

atEthe-sam the pinch-,seal 4.1 is l formedl-As shown;-each.member44,45 is providedljwith. .perfor'a.

tions 46. ;Each perforation is made by punching or piercing such that it is of irregular outline and has jag ged cdgcs hThe jagged edges extend out of the plane of the

member

44 or 45 and are embedded in thepinchscal41. When attaching the

members

44,45 some of the material of the pinch-seal 41 extrudes into the perforations 46 and expands or mushrooms somewhat. Thus firmattachment of the

members

44, 45 to the pinch-seal 41 isachieved. I

The

metal members

44,45 are shaped such that they correctly centre and align the lamp 40 in optical apparatus including a reflectorand lens when the lamp is installedin a holder designed therefor. In particular, the

members

44,45 are apertured at 47 and notched at 48. Thc apcrture 47 and notch 48 co-operate with locating formations in the holder to position the lamp 40 with accuracy laterally and longitudinally relative to referencepoints associated with a lens or reflector of the optical apparatus, a'swillbe familiar to designers of lamps and optical apparatus. I

One face'of the pinchseal 41 is provided with an axially-aligned ridge 49 located adjacent the member 44. This ridge 49 may co-opcrate with a keying structure in the holder to locate the lamp 40 accurately with respect to the optical axis of the apparatus. A similar ridge may,if desired, be provided in the opposite face of the pinch-seal 41. The ridge or ridges can be formed by shap'ed 'metal members 'as described above in rela- "tion to FIGS. 4, 5 and 6.

'FIG. '8 shows a lamp 50 provided with a metal base or cap 51. The cap 51 is attached by welding or the like to a pair of transversemetal members 52 which are attached to a pinch seal 53. The transverse members 52 are attached to the pinch-seal'53 in the same way as the

members

44, 45 are attached to the pinch-seal 41 as shown in FIG. 7. An insulating disc 54 forms the bottom of the cap 51 and carries a pair of contact pads 55. Lcad in conductors 56 are electrically connected to the pads '55 and extend into the pinch seal 53 for connection to a filament 57 in a conventional manner.

This arrangement provides a cement-free attachment of the cap 51 to the lamp 50 which is effectively temperature resistant and also facilitates the manufacture of prefocus lamps. Whilst the cap 51 is shown having a form suited to bayonet-type lamp-holders, it will be recognised that the cap 51 could readily be made to suit a screw-type lamp-holder or could form a pre-focus base.

The-attachment of metal locating members as described above' isapplicable to the manufacture of nume'rous varieties of pinch-sealed lamps, including those having hard-glass and fused silica envelopes. The

metal members

10,30 should have thermal coefficients of expansion which'match the particular vitreous material used for the

envelopes

17,33. For soft glass, nickelchrome-iron alloys, stainless steels, copper bronzes and copper/coated alloys are suitable. For hard glass, (borosilicates and aluminosoilicates), iron-nickel-cobalt alloys (FERNICO), molybdenum and tungsten are suitable, and for fused silica, molybdenumis preferred.

1. An electric lamp having internal components, said lamp'cornprising l ,7 I i an envelope with a pinch seal;

metal embers secured to the rial of the pinch seal by pressing said portions into said material in mechanical engagement therewith to hold the metal members in a predetermined position relative to the internal components of the lamp.

2. An electric lamp as claimed in claim 1 in which each of said one or more metal members has the form of a plate, said portions which are embedded in the material of the pinch seal projecting from the plate.

3. A lamp as claimed in claim 2 in which each plate is formed with an integral lug, the lugs extending substantially in a common plane and being adapted to support the lamp.

4. A lamp as claimed in claim 2 in which said portions projecting from each plate are bent-up edges of the plate.

5. A lamp as claimed in claim 4 in which there are two metal members attached to opposite faces of the press-seal each being in the form of an elongated plate with its longitudinal edges bent up to form a channel member, the said edges of said portions are embedded in the material of the press.

6. An electric lamp as claimed in claim 1 in which each of said one or more metal members has one or more apertures, the material of the pinch seal being extruded through and engaging the edges of said one or more apertures to secure each of said one or more metal members in its predetermined position.

7. An electric lamp as claimed in claim 1 and further including one or more leads passing through the pinch seal, the outer ends of the leads being attached to respective ones of said or more said metal members.

8. A method of making an electric lamp having an envelope with a pinch seal comprising the steps of pressing one or more shaped metal members against the external faces of the pinch seal of said lamp while the vitreous material of the seal is at a temperature such that it is plastically deformable, the said material thereby deforming to produce a mechanical interengagement of the material with the metal members.

Claims

1. An electric lamp having internal components, said lamp comprising an envelope with a pinch seal; one or more shaped metal members secured to the external faces of the pinch seal, portions of the metal members being embedded within the material of the pinch seal by pressing said portions into said material in mechanical engagement therewith to hold the metal members in a predetermined position relative to the internal components of the lamp.