Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
  • H01J5/50—Means forming part of the tube or lamps for the purpose of providing electrical connection to it
  • H01J5/54—Means forming part of the tube or lamps for the purpose of providing electrical connection to it supported by a separate part, e.g. base
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J5/00—Details relating to vessels or to leading-in conductors common to two or more basic types of discharge tubes or lamps
  • H01J5/50—Means forming part of the tube or lamps for the purpose of providing electrical connection to it
  • H01J5/54—Means forming part of the tube or lamps for the purpose of providing electrical connection to it supported by a separate part, e.g. base
  • H01J5/62—Connection of wires protruding from the vessel to connectors carried by the separate part
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J61/00—Gas-discharge or vapour-discharge lamps
  • H01J61/70—Lamps with low-pressure unconstricted discharge having a cold pressure < 400 Torr

Definitions

• the invention relates to a capped electric lamp comprising: a light-transmitting tubular lamp vessel which is sealed in a vacuumtight manner; an electric element inside the lamp vessel; a lamp cap provided with a projecting contact pin and fixed to the lamp vessel; an electrical conductor connected to the electric element and to said contact pin, said lamp cap comprising a housing of metal plating which has a cylindrical shell and an axis, and integral therewith a base which is transverse to the axis and remote from the lamp vessel and which has an opening, in which base a cavity is formed in which an insulator plate is retained by a flanged portion in the housing so as to cover said opening, which insulator plate supports said contact pin such that said contact pin enters the opening.
• the cavity in the base of the lamp cap shell is formed in that the base is locally depressed inwards.
• said plate is fixed in the cavity by means of a flanged portion which is made in the base.
• the flanged portion makes the entrance of the cavity smaller and thus closes in the plate.
• the formation of the cavity has made the housing locally double-walled, which gives the housing a comparatively large material content.
• the known lamp is a tubular fluorescent lamp which has two contact pins at its lamp cap.
• the pins must project from the base over a predetermined minimum length.
• the flanged portion which keeps the insulator plate in place has a thickness of twice the material thickness of the housing.
• the contact pins accordingly project less far from the base by said thickness than they do outside the insulator plate. They must be extra long to compensate for this.
• This is a disadvantage the more so in the frequently used tubular fluorescent lamps which have two such lamp caps. These latter lamps must be rotated about their axis through 90° when placed in a lampholder so as to bring the contact pins into contact with contact points of the holder.
• the mechanical resistance of the lampholder must be overcome during this by the connection between the lamp vessel, which is rotated about its axis, and the housing of the lamp cap, and by the connection between the housing of the lamp cap and the insulator plate, and by the connection between the insulator plate and the contact pins. Should the insulator plate rotate relative to the housing, the conductors to the contact pins could become short- circuited with one another and/or torn loose, and/or the lamp would not lie in the lampholder in a fixed position. In the known lamp, where the base has a separate opening for each contact pin, a rotation of the insulator plate may result in a short-circuit through and a voltage across the housing of the lamp cap.
• the known lamp cap has a special mark in its shell, i.e. a groove, for indicating where the contact pins are present when the lamp is placed in a holder, i.e. what rotational position is occupied by the lamp.
• this object is achieved in that the base is deformed in outward direction for forming the cavity therein, and the flanged portion inside the housing presses against a side of the insulator plate which faces towards the lamp vessel.
• the lamp according to the invention has the advantage that the contact pin projects less far from the base than from the insulator plate by no more than a length equal to the thickness of the base, and also that the housing has a comparatively small material content because double-walled portions are avoided in the housing, apart from the flanged portion.
• the electric element of the lamp may be an electrode in an ionizable medium.
• An electrical conductor may be present opposite the lamp cap around the lamp for coupling the lamp capacitively to a supply source there.
• the lamp will have a pair of electrodes in an ionizable medium, such as a rare gas, or a rare gas with mercury, as the electric element.
• the lamp vessel may be coated with a fluorescent material. The lamp vessel then usually has two lamp caps.
• the lamp may be designed for preheating an electrode by means of current passage prior to lamp ignition.
• the lamp cap has two contact pins, each connected to a respective conductor connected to the electrode.
• the insulator plate has an elongate shape, and the cavity in the base has a corresponding shape.
• This embodiment has various advantages: the housing and the insulator plate are locked against mutual rotation by their very shapes, so that friction for achieving this locking effect is of no importance; the base is not rotationally symmetrical, so that it can be observed from laterally of the lamp which position the lamp cap occupies with its pins relative to a lampholder. Specific marks on the shell of the housing may accordingly be omitted; the insulator plate has a smaller surface area.
• the lamp cap requires less of this comparatively expensive material; the insulator plate may be cut from a larger plate with comparatively small material losses owing to wastage; and the flanged portion can support the plate to closer to its center, so that a thinner, less expensive plate can be used for achieving the same strength.
• the lamp cap may be coupled mechanically to the lamp vessel, for example in that the lamp cap is indented into a cavity in the lamp vessel.
• the lamp cap may be fastened with cement.
• the insulator plate has a recess which is kept free by the base. Vapors evolved during curing of the cement in the lamp cap can escape through this. It is prevented thereby that said vapors build up a pressure inside the lamp cap which would displace the lamp cap before the cement has cured.
• the insulator plate may have one or several holes for this purpose.
• Fig. 1 shows the lamp in side elevation
• Fig. 2 shows the lamp cap viewed along II in Fig. 1;
• Fig. 3 shows the lamp viewed along III in Fig. 2;
• Fig. 4 shows the lamp cap viewed along IV in Fig. 2.
• the capped electric lamp has a light-transmitting tubular lamp vessel 1 which is sealed in a vacuumtight manner and in which an electric element 2 is arranged.
• a lamp cap 3 provided with a projecting contact pin 4 is fixed to the lamp vessel 1.
• An electrical conductor 5 is connected to the electric element 2 and to the contact pin 4.
• the lamp cap 3, see also Figs. 2 to 4, comprises a housing 10 of metal plating, having a cylindrical shell 11 and an axis 12, and integral therewith a base 13 which is transverse to the axis 12, which is remote from the lamp vessel 1, and which has an opening 14.
• a cavity 15 is formed in the base 13, in which cavity an insulator plate 16 is retained over the opening 14 by means of a flanged portion 17 in the housing 10.
• the insulator plate 16 supports the contact pin 4, said contact pin 4 projecting into the opening 14.
• the base 13 is deformed in outward direction for the formation of the cavity 15 therein, and the flanged portion 17 presses inside the housing 10 against a side 18 of the insulator plate 16 which faces towards the lamp vessel 1.
• the lamp shown has two identical lamp caps 3, each having two contact pins 4, of which each is connected to the electric element 2 via a respective conductor 5.
• the lamp shown is a low-pressure discharge lamp whose lamp vessel 1 has a coating of fluorescent powder.
• the lamp has two electrodes in an ionizable medium, rare gas and mercury, so as to form the electric element 2, which electrodes can be heated by current passage for the purpose of lamp ignition.
• the lamp cap 3 shown, see Figs. 2 to 4 has a housing 10 of aluminum which was formed from plate material by deep-drawing.
• the insulator plate 16 for example made of synthetic resin bonded paper, or alternatively from some other insulator material, for example entirely from synthetic resin, is provided with contact pins 4, fixed therein by flanging, and subsequently introduced into the cavity 15 from the inside.
• the insulator plate 16 is subsequently fixed in that the flanged portion 17 is made, visible from the outside of the lamp cap 3 as a circumferential sharp seam.
• the insulator plate 16 is elongate in shape, see Figs. 2 to 4, and the cavity 15 has a corresponding shape.
• the flanged portion 17 presses against the insulator plate 16 substantially circumferentially around the axis 12.
• the insulator plate 16 has a recess 19, two recesses in Figs. 2 and 3, left open by the base 13 for the purpose of venting the lamp cap 3.
• the insulator plate 16 is enclosed in the cavity 15 with narrow fit. Partly as a result of this, a flanged portion 17 which only has a small overlap over the insulator plate 16 can suffice for nevertheless achieving a strong connection.
• the dimension of the flanged portion implies that comparatively little material is required for the housing. The deformation of the base in outward direction also contributes to this because the housing has no double-walled portions apart from the flanged portion.
• the opening 14 in the base 13 is common to the contact pins 4. Since the insulator plate 16 completely covers the opening 14 in the base
• the support 13 which the exception of the recess 19, see Fig. 2, and is supported by the base 13 on the outside over its entire circumference, except for the recess 19 again, it is possible to choose the support at the short edges of the plate 16 to be small, so that the distance from the housing 10 to the adjacent contact pin 4 is nevertheless comparatively great.
• the support may be chosen to be wider at the long sides of the plate 16, straight sides in the Figure, while maintaining the same minimum distance to the contact pins 4 both in the cross-section parallel to Fig. 3 and in the cross-section of Fig. 4.
• the straight sides of the insulator plate 16 manifest themselves on the outside of the lamp cap 3 in the form of a flat side 20 of the housing 10, see Figs. 1 to 3, which runs parallel to a plane through the contact pins 4, see Fig. 4, as a result of the fact that the plate 16 and the cavity 15 have the same shape, so that the orientation of the contact pins 4 is apparent therefrom when a lamp 1 is placed in a lampholder.

Landscapes

• Common Detailed Techniques For Electron Tubes Or Discharge Tubes (AREA)
• Fastening Of Light Sources Or Lamp Holders (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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ID=8227937

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (6)

Citations (4)

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• 1998
  • 1998-01-07 JP JP10529164A patent/JP2000507040A/ja not_active Ceased
  • 1998-01-07 ID IDW980077D patent/ID20237A/id unknown
  • 1998-01-07 EP EP98900015A patent/EP0897588B1/en not_active Expired - Lifetime
  • 1998-01-07 DE DE69813693T patent/DE69813693T2/de not_active Expired - Fee Related
  • 1998-01-07 CN CN988000288A patent/CN1133192C/zh not_active Expired - Fee Related
  • 1998-01-07 WO PCT/IB1998/000016 patent/WO1998032146A1/en not_active Ceased
  • 1998-01-07 BR BR9805895A patent/BR9805895A/pt not_active IP Right Cessation
  • 1998-01-15 US US09/007,553 patent/US6002200A/en not_active Expired - Fee Related

Patent Citations (4)

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