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WO1999060604A1 - Lampe incandescente a pinces de filament enroule sans mandrin - Google Patents

Lampe incandescente a pinces de filament enroule sans mandrin Download PDF

Info

Publication number
WO1999060604A1
WO1999060604A1 PCT/IB1999/000834 IB9900834W WO9960604A1 WO 1999060604 A1 WO1999060604 A1 WO 1999060604A1 IB 9900834 W IB9900834 W IB 9900834W WO 9960604 A1 WO9960604 A1 WO 9960604A1
Authority
WO
WIPO (PCT)
Prior art keywords
legs
flat section
lamp
raised
coil
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/IB1999/000834
Other languages
English (en)
Inventor
John Ingham
Chris Venicx
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
Philips AB
Philips Svenska AB
Original Assignee
Koninklijke Philips Electronics NV
Philips AB
Philips Svenska AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips Electronics NV, Philips AB, Philips Svenska AB filed Critical Koninklijke Philips Electronics NV
Publication of WO1999060604A1 publication Critical patent/WO1999060604A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K1/00—Details
    • H01K1/18—Mountings or supports for the incandescent body

Definitions

  • Incandescent lamp having clamps for coiled filament without mandrel.
  • the invention relates to a lamp comprising a metal filament which incandesces when an electric current passes therethrough, said metal filament comprising a pair of legs and a coil extending through said legs, each leg having a diameter, a pair of clamps holding respective legs. More particularly, the invention relates to an improved clamp which prevents collapse of the primary coil in the legs.
  • Incandescent filaments typically are-made of potassium doped tungsten wire having a diameter on the order of 20 - 70 ⁇ m. This is wound on a primary mandrel having a diameter on the order of 80 -150 ⁇ m in order to form a primary coil having a external diameter on the order of 100 - 300 ⁇ m. This composite is then wound on a secondary mandrel having a diameter on the order of 300 - 800 ⁇ m in order to form a secondary coil or barrel. The secondary mandrel is retracted or dissolved, and the primary mandrel is then removed in whole or in part by dissolving.
  • the coiled coil type filament has a secondary coil or barrel located between a pair of legs which are clamped in lead wires which transmit current through the filament to cause incandescence.
  • the primary mandrel may be retained in the legs. This is accomplished by coating the portions of the primary mandrel extending into the legs with wax and dissolving the central portion.
  • the primary mandrel is preferably molybdenum, which is dissolved in a known acid which does not attack the tungsten.
  • the secondary mandrel is to be dissolved, it is also molybdenum.
  • the primary mandrel is removed completely, which is more economical than a selective removal. Without the support provided by a mandrel retained in the legs, however, the primary coil may deform too much in the clamps, causing the tungsten wire to split.
  • the lead wires have a diameter on the order of 0.5 mm, and according to the prior art are formed over the legs into a teardrop shaped clamp wherein the leg of the filament is positioned in the base of the teardrop, coaxial with the radius of curvature of the clamp.
  • U.S. Patent No. 3,988,630 discloses a lead wire forming apparatus for a mandrelless filament.
  • This patent shows as prior art the steps for forming the teardrop shaped clamp described above using a single pair of forming dies, and further shows improved forming steps using first dies which preform the lead wire to form a hook, and second dies which clamp the hook about the leg.
  • the legs are precisely positioned so that a closely controlled compression of the primary coil is achieved. The high stresses imposed by using the primary coil as an anvil during the initial forming are avoided.
  • disadvantageous is the necessity of precisely positioning the legs and undertaking two forming steps for clamping the filament in the leads adds to the time and expense of manufacturing the lamp.
  • a lamp of the type as described in the opening paragraph is characterized in that each clamp being formed from a lead wire having a first surface and an opposed second surface, said first surface having a flat section between two raised sections, said flat section being recessed below said raised section by a depth less than half the diameter of said legs, each said lead wire being bent so that said raised sections are in mutual abutment and said flat section forms parallel clamping surfaces which engage one of said legs therebetween.
  • the primary coil in the leg is compressed only to a degree defined by the depth of the recess, regardless of the position of the leg with respect to the center of curvature about which the leg is folded.
  • the recess has a depth of up to 25% of the diameter of the primary coil, whereby the leg is compressed by up to 50%.
  • the diameter of the leg (primary coil) is 100 ⁇ m
  • the depth of the recess is up to 25 ⁇ m.
  • the lead wires are preferably molybdenum and typically have a diameter of 0.3, 0.4, 0.5, or 0.6 mm.
  • the raised surface at the distal end of the lead is formed by an "S" bend.
  • the offset between the raised section and the flat section may be varied in accordance with the desired distance between the clamping surfaces.
  • the distance between the parallel clamping surfaces is controlled by a single raised section, the flat section being recessed by a depth equal to the desired distance between the clamping surfaces.
  • the second surface of the lead wire is provided with a flat section which extends beyond the flat section of the first surface in both directions, thereby lying opposite the raised sections.
  • the flat sections are formed by stamping the end of the lead in dies.
  • the geometry of the clamp according to the invention offers the advantage of using a mandrelless coil and at the same time assures that the leg will be compressed by a controlled amount every time, regardless of the exact positioning of the leg with respect to the clamping surfaces. It will be understood that the clamp according to the invention is also useful for a filament consisting of a single coil.
  • Figure 1 is a plan view of one end of a coiled coil type filament
  • Figure 2 is a plan view of leads clamped directly to a filament
  • Figure 3 is an end view of the clamps of Figure 2, shown enlarged, according to the prior art
  • Figure 4A is a plan view showing the first or inside surface of the clamp according to the invention.
  • Figure 4B is a plan view of the second or outside surface of the clamp
  • Figure 4C is an end view showing the opposed first and second surfaces
  • Figure 4D is an end view of the clamp as bent when the filament is received
  • Figure 4E is an end view of the closed clamp.
  • Figure 5A is a section view of a second embodiment of the clamp
  • Figure 5B is a section view of a third embodiment of the clamp
  • Figure 5C is a view of a fourth embodiment of the clamp.
  • Figure 1 shows a coiled coil type filament 10 consisting of a potassium doped ("Non-Sag") tungsten wire which has been wound around a primary mandrel to form a primary coil 12 extending throughout the length of the filament, and has been subsequently wound around a secondary mandrel to form a secondary coil 14 which is centrally located.
  • the secondary mandrel has been removed by simply retracting it from the secondary coil, while the primary mandrel - preferably molybdenum - has been subsequently removed by dissolving it in acid.
  • the central or secondary coil 14 is located between a pair of opposed legs 16 and separated therefrom by so-called K zones 18.
  • the primary coil is typically wound with a pitch of 340 threads per inch and a diameter of 130 ⁇ m
  • the secondary coil is typically wound with a pitch of 85 threads per inch and a diameter of 450 ⁇ m.
  • FIG 2 is a plan view of leads 20 directly clamped to a filament 10, which is schematically shown without a primary coil for simplicity.
  • Each lead 20 is provided with a clamp 22 which is formed around a respective leg 16 to retain it and provide electrical current thereto.
  • the remainder of the lamp includes a base, a bulb, and a halogen filling.
  • the design is also suitable for conventional incandescent lamps having a vacuum or inert gas filling.
  • the term "incandescent lamp” includes halogen filled lamps having a filament.
  • Figure 3 shows the teardrop shaped clamp 21 of the prior art. Since the manufacturing process typically involves holding the filament by the barrel to position the legs in the hook prior to fully closing the clamp, the leg may not be precisely positioned at the center of curvature of the teardrop, and the leg may be overstressed in compression.
  • Figure 4A is plan view of a first surface 24 of the end of a lead according to the invention prior to forming.
  • the first surface 24 is formed with a flat section 26 which is flanked by two raised sections 28, 29 and recessed therebelow.
  • Figure 4B is a plan view of the opposed second surface 30 which has a flat section 32 extending to the distal end 33 of the lead. As shown in the side view of Figure 4C, the flat section 32 extends beyond the opposed flat section 26 so that it lies opposite the raised sections 28, 29.
  • Figure 4D shows the partially formed clamp 22 with abend 23 having a center of curvature between mutually facing sections 27 of the first flat section 26. At this point in time the leg 16 is positioned between these mutually facing sections 26, which form the clamping surfaces.
  • Figure 4E shows the finished clamp with the filament leg 16 in place, the clamping surfaces 27 in parallel, and the raised sections 28, 29 abutting.
  • the use of opposed flat surfaces 26, 32 is known per se in order to reduce surface stresses during forming.
  • the use of raised sections 28, 29 limits the closure of the gap so that the clamping surfaces 27 remain parallel along the length of the finished clamp. This assures that the primary coil in the legs will not be overstressed, which could cause the wire to split and fail during transport or in use.
  • Figure 5 A depicts an alternative embodiment having a raised sectiom 29 at only one end of the flat section 26, which extends all the way to the distal end 33 of the lead wire.
  • the depth of the flat section below the single raised section is equal to the desired distance between the parallel clamping surfaces, which in turn is determined by the diameter and desired compression of the coil in the leg of the filament.
  • Figure 5B depicts an embodiment which is similar to Figure 5 A insofar as there is a raised section at only one end of the flat section 26 of the first surface. However the opposed flat section 32 of the second surface 30 is also recessed. This essentially provides a manufacturing advantage during the forming.
  • Figure 5C like the principle embodiment shown in Figures 4A-4E, depicts two raised sections, one at either end of the flat section 26. However here the raised section 28 at the distal end 33 is made by forming an S bend 34 in the lead wire. The amount of offset in the bend determines the distance between the parallel clamping surfaces 27 formed by the flat section 26. Thus a single stamped wire profile may be formed to accommodate a range of leg diameters.

Landscapes

  • Wire Processing (AREA)

Abstract

Ce filament incandescent (10), comprenant un premier enroulement (12) sans mandrin, est maintenu dans des pinces (22) formées sur les extrémités de fils conducteurs métalliques (20) présentant des première (24) et seconde (30) surfaces opposées à sections plates (20). La section plate de la première surface est évidée en dessous des sections surélevées (28, 29), à l'une et l'autre extrémité, d'une profondeur déterminée qui est inférieure à la moitié du diamètre du premier enroulement (12). Chaque fil conducteur (20) est replié de manière que les sections surélevées (28, 29) viennent buter l'une contre l'autre et que la section plate (20) de la première surface forme des surfaces de serrage (27) parallèles, se faisant mutuellement face et entrant en contact avec le segment (16) du filament (10), comprimant ainsi le premier enroulement (12) selon un degré bien déterminé, sans exercer de contrainte exagérée sur celui-ci.
PCT/IB1999/000834 1998-05-20 1999-05-10 Lampe incandescente a pinces de filament enroule sans mandrin Ceased WO1999060604A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US8245098A 1998-05-20 1998-05-20
US09/082,450 1998-05-20

Publications (1)

Publication Number Publication Date
WO1999060604A1 true WO1999060604A1 (fr) 1999-11-25

Family

ID=22171305

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB1999/000834 Ceased WO1999060604A1 (fr) 1998-05-20 1999-05-10 Lampe incandescente a pinces de filament enroule sans mandrin

Country Status (1)

Country Link
WO (1) WO1999060604A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6639364B1 (en) 2000-06-29 2003-10-28 Koninklijke Philips Electronics N.V. Halogen incandescent capsule having filament leg clamped in press seal
EP1255279A3 (fr) * 2001-05-03 2005-10-12 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Lampe incandescente à halogène
EP2202781A1 (fr) * 2008-12-23 2010-06-30 Flowil International Lighting (Holding) B.V. Lampe à incandescence et support pour filament correspondant
US8823252B1 (en) * 2013-06-17 2014-09-02 Ford Global Technologies, Llc Incandescent lamp having bent filament terminal ends

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2145186A (en) * 1938-07-01 1939-01-24 Gen Electric Connection for filament and lead wires
JPS4937422U (fr) * 1972-07-13 1974-04-02
US3922630A (en) * 1964-12-03 1975-11-25 Us Navy Automatic vehicle positioning system
JPH05182641A (ja) * 1991-12-27 1993-07-23 Toshiba Lighting & Technol Corp 管球用電極及び白熱電球
JPH06231736A (ja) * 1993-02-09 1994-08-19 Toshiba Lighting & Technol Corp リード線および電球
WO1998048448A1 (fr) * 1997-04-18 1998-10-29 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Ampoule electrique

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2145186A (en) * 1938-07-01 1939-01-24 Gen Electric Connection for filament and lead wires
US3922630A (en) * 1964-12-03 1975-11-25 Us Navy Automatic vehicle positioning system
JPS4937422U (fr) * 1972-07-13 1974-04-02
JPH05182641A (ja) * 1991-12-27 1993-07-23 Toshiba Lighting & Technol Corp 管球用電極及び白熱電球
JPH06231736A (ja) * 1993-02-09 1994-08-19 Toshiba Lighting & Technol Corp リード線および電球
WO1998048448A1 (fr) * 1997-04-18 1998-10-29 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Ampoule electrique

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6639364B1 (en) 2000-06-29 2003-10-28 Koninklijke Philips Electronics N.V. Halogen incandescent capsule having filament leg clamped in press seal
EP1255279A3 (fr) * 2001-05-03 2005-10-12 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Lampe incandescente à halogène
EP2202781A1 (fr) * 2008-12-23 2010-06-30 Flowil International Lighting (Holding) B.V. Lampe à incandescence et support pour filament correspondant
US8823252B1 (en) * 2013-06-17 2014-09-02 Ford Global Technologies, Llc Incandescent lamp having bent filament terminal ends

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