Capped electric lamp for operation at mains voltage

Abstract: The capped electric lamp for use at mains voltage comprises a lamp vessel (1), a lamp cap (10) and a mounting member (40). A shell (20) of the cap (10) is secured to the lamp vessel (1) by means of an adhesive compound (11) and is coupled to an insulator body (30) of the cap (10). Current supply conductors (6) extend from the lamp vessel to beyond the insulator body and are connected outside that body to contact pins (31) anchored in the insulator body (30). The mounting member (40), through which the contact pins (31) extend, is secured to the insulator body (30). The member (40) may have one of several shapes, e.g. be composed of two parts of which one is rotatably provided in the other. The lamp is of a reliable construction and can be readily manufactured.

Description: The invention relates to a capped electric lamp for operation at mains voltage comprising: a lamp vessel which is sealed in a vacuumtight manner and which at an end portion thereof is fused to a tube which projects into the lamp vessel and which surrounds an exhaust tube; an electric element in the lamp vessel connected to current supply conductors which issue to the exterior alongside the exhaust tube; a lamp cap provided with a shell having an axis, a first end of which is fixed around the said end portion of the lamp vessel with an adhesive compound, and a second end of which is coupled to an insulator body; contact pins fixed in the insulator body and issuing to the exterior therefrom, and connected to respective current supply conductors. A lamp of the kind described in the opening paragraph and suitable for consuming a low power is known from US 2 730 689. The lamp has the disadvantage that a lampholder is required for mounting the lamp against a substrate, for example against a wall, for example of an electric appliance such as, for example, a refrigerator or a microwave oven. Moreover, the lamp provides no points of application for a positive retention by a lampholder. The lamp can be held by its contact pins only. Another disadvantage of the known lamp is that the current supply conductors must be passed between the legs of respective contact pins, which each consist of a metal strip curved in a hairpin shape, during the assembly of the lamp vessel with the lamp cap. Then, the lamp cap is to be applied around the lamp vessel. During this, the current supply conductors must pass on further between said legs of their own accord. If they do not, there is a great risk of short-circuiting inside the lamp cap. Subsequently, the contact pins are flattened, by which contact with the current supply conductors is to be achieved. Such a contact is susceptible to get lost by corrosion of the supply conductors and/or contact pins. It is an object of the invention to provide a lamp of the kind described in the opening paragraph, as well as a unit for use in this lamp, which inter alia avoids the necessity of using a lampholder and renders possible a positive retention of the lamp, and which is also of a reliable construction which can be easily manufactured. This object is achieved by the features defined in the characterizing portion of independent claim 1. In the lamp according to the invention, the connection between the current supply conductors and the contact pins is made outside the insulator body. This may be done when the lamp cap has been applied around the lamp vessel. The connection may be effected, for example, through welding or soldering, for example laterally against the contact pins. The connection may be inspected for its correctness and the current supply conductors may be tautened beforehand, so that an excess length inside the lamp cap can be avoided. The mounting member renders possible a positive retention of the lamp by the body which is to support the lamp, for example a wall of an appliance, while nevertheless a lampholder is dispensed with. The lamp may be electrically supplied in that a connector present at a cable which is connected to an electrical supply is applied to the contact pins. It is favourable if the mounting member has a projecting sheath from which the contact pins issue to the exterior, or a separate sheath for each contact pin. It can be assured in this way that the contact pins do not touch the wall against which the lamp is mounted and that no electrical contact is made with this wall if the latter is of metal. It is favourable if the contact pins have a widened portion which is to butt against a surface of the mounting member facing towards the insulator body. This provides the safeguard that the lamp will retain the contact pins, even if a pulling force is exerted on them. Such pulling forces can be exerted on the contact pins when a connector is removed from the lamp. If a lamp should lose its grip on a contact pin during this, this pin would have to be removed from the connector while this pin could still be under electrical tension. In the lamp according to the cited US 2 730 689, the contact pins are inserted in the insulator body from the outside and fixed therein by flattening. There is a risk, however, of the lamp losing its grip on the pins when the lamp is forced from a holder. In a favourable embodiment, the insulator body is made of synthetic resin and has cavities in a surface remote from the lamp vessel, in which cavities respective contact pins are anchored. The contact pin may be provided with, for example, barbed hooks or teeth with which it has fixed itself in the cavity. It is favourable that the lamp cap in this embodiment can be easily assembled with its contact pins in that the contact pins are inserted in the insulator body until they abut. The contact pins are securely held by the insulator body during the application of a connector, whereas during the removal of the connector the simultaneous removal of a contact pin is blocked by the mounting member. The mounting member may have a flange-shaped portion with holes through which the lamp can be fixed against a wall with screws, or with resilient pins, so that the lamp may be fixed with these pins in holes in a wall. Favourable are embodiments in which resilient tongues curved in a hairpin shape project from the mounting member, for example at a flange-shaped portion, which tongues each have a free end with a wedge-shaped thicker portion. The tongues may then extend alongside the axis of the shell to beyond a location where they project from the mounting member. In these embodiments, the lamp may be inserted in an opening in a wall, either with the lamp cap facing forwards, or with the lamp vessel facing forwards, in order to butt against this wall with the mounting member and to hook behind this wall with the wedge-shaped thicker portions at the tongues. The lamp is mounted against a wall thereby in a very fast, easy, and reliable manner, and may also be readily removed e.g. in that the tongues are bent. It is favourable if the mounting member has an upright rim in which the insulator body is accommodated. Such a rim gives the current supply conductors an improved electrical insulation from the surroundings of the lamp and is capable of preventing the penetration of moisture into the interior. The insulator body has for each of the current supply conductors a narrowing channel which issues from the insulator body near where a respective contact pin projects to the exterior. The current supply conductors thereby project to the exterior in an accurately determined location and can thus be easily found by the assembling machine in order to be fastened to the contact pins. This embodiment renders it possible for the current supply conductors to be fully separated from one another by the adhesive compound, the insulator body and the mounting member at least from the point where they leave the end portion of the lamp vessel. A discharge arc in a current supply conductor arising through fusion of a fuse wire therein at the end of lamp life is impeded to leap over to the other conductor as a result. A discharge arc having a relatively long duration is avoided by this. It is favourable, also on account of the easy assembly of the lamp cap, if the insulator body is made of synthetic resin. The mounting member may then be easily fastened to the insulator body, for example with screws. The said body then has for this purpose cavities in a plane remote from the shell for accommodating the bodies of screws. It is favourable if the screws are countersunk to below a surface of the mounting member. This member can then be mounted against a flat wall. The shell of the lamp cap may be a metal ring. Such a ring has the advantage that it can be heated to a comparatively high temperature if heating should be nesessary for, for example, curing the adhesive compound, such as a cement, e.g. a lamp cement, or for effecting adhesion. This can be realized in a comparatively short time. It is also easy to fasten the metal ring to an insulator body made of synthetic resin. This body need not be formed in a mould in the presence of the ring then. It is favourable if the insulator body has a collar and the metal ring has an inwardly flanged rim at its second end cooperating with said collar. The metal ring may surround the insulator body with clamping fit. Means may be present for locking the two parts against mutual rotation. It is favourable for this purpose if the insulator body has projections at the collar which grip into the flanged rim. This rim may have recesses for this purpose, for example if brass or bronze is used, or it may be deformed by said projections, for example if aluminium is used. A reflector may be readily fastened to the metal ring for concentrating the generated radiation into a beam transverse to the axis or in the direction of the axis. Alternatively, a cover which transmits no or little light may be provided over the lamp vessel so that the lamp is used exclusively or almost exclusively as a heat source. The cover may be fastened to the lamp vessel or alternatively to the metal ring, for example, with an adhesive agent, for example silicone cement. The lamp may be used, for example, as a defroster. A metal ring, however, means that an additional component is to be assembled together with other components. It is accordingly attractive if the shell of the lamp cap is integral with the insulator body. It is favourable in that case for the shell of the lamp cap to consist of synthetic resin, for example of polyphenylene sulphide or of a liquid-crystalline polymer. The insulator body may be formed, for example from synthetic resin, in the presence of the contact pins. A very secure anchoring of the contact pins may be obtained in that case which guarantees that the insulator body, or the lamp cap, does not lose its grip on the contact pins. It is favourable also in this case for the insulator body to have narrowing channels for the current supply conductors. The contact pins, however, may be inserted into the insulator body from the side facing the lamp vessel so that an anchorage of these pins is ensured also in the case of a pulling force. The assembly with the mounting member is very convenient if the contact pins each have a recess, for example a hole, and the mounting member has resilient projections which each grip into a respective recess, thus keeping the mounting member fixed, connected to the insulator body. The mounting member is then provided simply by passing it over the contact pins up to an end position in which the projections each enter a corresponding recess. The lamp according to the invention may be so constructed that it radiates the generated light in a pattern which is not rotationally symmetrical. The electric element, for example an incandescent body, may be positioned, for example, transverse to the axis. Alternatively, the lamp may have a reflector or a screen at one side of the axis, for example a reflecting, scattering, or selectively light-transmitting coating. It may be desirable for such an optical means to be present in an aligned position relative to the mounting member. The lamp vessel must then be connected to the lamp cap in the correct orientation relative to this element. It is difficult to realize this in a mechanized manufacturing process. It is also possible that the lamp must have one orientation for the optical element in one application, for example in an appliance of a first provenance, but a different orientation in an appliance of a different provenance. In a favourable embodiment, the mounting member comprises a first part which is fixedly connected to the insulator body and which is rotatably held in a second part, keeping this second part coupled to the first part. A convenient construction is one in which the first part rests against a stop in the second part, which stop faces away from the insulator body. The first part of the mounting member together with the lamp vessel, lamp cap and contact pins, is capable of being rotated in a second part of the mounting member which is fixed in relation to the surroundings. In an attractive modification of the embodiment last mentioned, the first and the second part of the mounting member have cooperating means which provide several rotational positions with a comparatively high degree of fixation against rotation. The lamp vessel can then be rotated relative to the second part, and thus relative to the surroundings, so as to reach a desired position and be kept fixed in this position. The cooperating means may be formed by mutually engaging ribbed rims or by projections and a ribbed rim. Such a ribbed rim may extend in a plane transverse to the axis, but in a favourable embodiment it lies on the surface of a coaxial cylinder or cone. Embodiments of the capped electric lamp according to the invention are shown in the drawings, in which Fig. 1 shows a lamp in side elevation with the lamp cap in longitudinal section; Fig. 2 shows the lamp of Fig. 1 with a different reflector, rotated through 90°; Fig. 3 shows a different embodiment, represented as in Fig. 1; Fig. 4 shows a further embodiment similarly represented; Fig. 5 shows a unit for a modification of Fig. 1; Figs. 6a, b, c show the insulator body of the preceding Figures seen according to VIa, in longitudinal section, and according to VIc in Fig. 5, respectively; Figs. 7a and b show the metal ring of Figs. 1 to 5 seen away from the lamp vessel and in longitudinal section, respectively; Fig. 8 shows a contact pin in side elevation; Fig. 9a shows a modification of Fig. 5 in side elevation with the lamp cap in longitudinal section, Figs. 9b, c, d showing a mounting member suitable therefor in longitudinal section, in side elevation partly in longitudinal section rotated through 90°, and in elevation seen along the line IXd in Fig. 9b; and Fig. 10a shows a further embodiment with a lamp cap in longitudinal section, with the first part of the mounting member in side elevation and in cross-section in Figs. 10b and c, while the second part is given in cross-section and elevation in Figs. 10d and e, respectively. In Fig. 1, the capped electric lamp for operation at mains voltage, for example a 100 W or 25 W/220-230 V lamp, has a lamp vessel 1 which is sealed in a vacuumtight manner and whose end portion 2 is fused to a tube 3 projecting into the lamp vessel and surrounding an exhaust tube 4. An electric element 5, an incandescent body in the Figure, but alternatively a pair of electrodes, is positioned in the lamp vessel and connected to current supply conductors 6 which issue to the exterior alongside the exhaust tube 4. A lamp cap 10 provided with a shell 20, a metal ring in the Figure, having an axis 21 is fixed with a first end 22 thereof around the end portion 2 of the lamp vessel with adhesive compound 11. At a second end 23 the shell is coupled to an insulator body 30. Contact pins 31, which are connected to respective current supply conductors 6, are fixed in the insulator body 30 and issue therefrom to the exterior. The current supply conductors extend to outside the insulator body 30 and are connected to respective contact pins 31 there, laterally in the Figure. A mounting member 40 of synthetic resin is connected to the insulator body 30. Only the contact pins 31 issue from this body to the exterior. The mounting member 40 has a separate, projecting sheath 41 for each contact pin 31, so that the pins remain electrically insulated when they are passed through an opening in a metal wall. Holes 43 are present in a flange-shaped portion 49 of the mounting member so that this member may be fastened to a wall with screws. A reflector 12 fastened to the ring 20 concentrates the generated light into a beam which is thrown to the exterior in axial direction. A widened portion 33 (Fig. 8) at the contact pins 31 butts against a surface 42 of the mounting member 40 facing the insulator body 30. The mounting member 40 of synthetic resin, for example of polyphenylene sulphide, or, if elasticity is required, polyamide or polyester, has an upright rim 46 in which the insulator body 30 is accommodated. The current supply conductors 6 run through respective narrowing channels 34 in the insulator body, each channel issuing near a respective contact pin 31 where it projects from the insulator body 30. The said conductors 6 are laterally fastened against the contact pins. The adhesive compound 11, for example lamp cement, the insulator body 30 and the mounting member 40 fully separate the current supply conductors 6 from one another up from the end portion 2 of the lamp vessel 1. The insulator body 30 is made of synthetic resin, for example of polyphenylene sulphide, and has a collar 35 which cooperates with an inwardly flanged rim 24 at the second end 23 of the metal ring 20 (see also Fig. 7). The ring 20 surrounds the insulator body 30 with clamping fit. Projections 36 at the collar 35 of the insulator body 30 constitute means which prevent relative rotation. They grip into the flanged rim 24 of the ring 20. The contact pins 31 are passed into cavities 32 in the insulator body from outside the lamp cap 10, and are anchored in these cavities. The lamp of Fig. 2 is identical to the lamp of Fig. 1 except for the reflector 13, which throws the light in transverse direction. The insulator body 30 and the mounting member 40 are fastened to one another with self-tapping screws 47. The insulator body 30 has for this purpose cavities 38 for accommodating the bodies 48 of screws 47. The screws 47 are countersunk to below the surface 49. In Fig. 3, the mounting member 50 has resilient tongues 54 which are curved in a hairpin shape and which have wedge-shaped thickened portions 55 at their free ends. The tongues extend alongside the axis 21 of the shell 20 to beyond the location where they are present at the mounting member 50. The lamp may be inserted through an opening in a wall 70 with the lamp vessel 1 facing forwards, the thickened portions 55 passing this wall while being pressed inwards and the surface 57 being checked against this wall. When the thickened portions 55 have passed the said wall, they spring back and enclose this wall in conjunction with the surface 57. In Fig. 4, the tongues 64 are oppositely directed to the tongues 54 of Fig. 3. The lamp can be inserted in a wall with the lamp cap 20, 30 facing forwards. The unit of Fig. 5 has the insulator body 30 and the metal ring 20 according to the preceding Figures. The lamp vessel 1' is elongate and carries a metal shell 7 which has a ribbed surface. The unit may be used as a heat radiator. The insulator body of Figs. 6a to 6c has a cavity 39 for accommodating an exhaust tube of a lamp vessel. Fig. 6c shows that the channels 34 for the current supply conductors issue close to a cavity 36 for the contact pins. The metal ring 20 of Figs. 7a, 7b has recesses 25 in its inwardly flanged rim 24 at its second end 23, which recesses can cooperate with projections at an insulator body so as to prevent mutual rotation. The contact pin 31 of Fig. 8 has a widened portion 33 which is to butt against a mounting member. The pin has a narrow portion with teeth 310 for fixing itself in a cavity of an insulator body. The widened portion 33 may butt against the insulator body in that case. When a connector is applied over a contact portion 311, the widened portion 33 offers resistance to shifting of the contact pin. When the connector is removed, the teeth 310 prevent the insulator body being pulled loose. The widened portion 33 safeguards this by butting against the mounting member. A current supply conductor can be laterally fastened to the pin at 312. The contact pin 31 has a recess 313 which is of importance for the embodiments of Figs. 9 and 10. The lamp according to the invention can be readily manufactured. In the embodiments described, the contact pins can be inserted into the insulator body and the metal ring can be slipped over the insulator body so as to be coupled thereto and form a lamp cap. An adhesive compound is provided in the metal ring and the lamp cap is passed towards a lamp vessel whose current supply conductors slide through the narrowing channels and arrive outside the insulator body, while the metal ring surrounds the end portion of the lamp vessel. The adhesion of the compound to the ring and to the lamp vessel is subsequently effected, as is the fastening of the current supply conductors to the contact pins. A chosen mounting member is to be slipped over the contact pins towards the insulator body and be fastened thereto in order to obtain a complete lamp. In Fig 9a, the lamp vessel 1 with its contents is identical to that of Fig. 1. Fastened to the lamp vessel there is a lamp cap 110 whose shell 120 and insulator body 130 are integral and consist of, for example, polyphenylene sulphide. The contact pins 31 were present during the formation of the lamp cap and are embedded therein. The unit of Fig 9a is to be provided with the mounting member 140 of Figs. 9b, c, and d. Parts thereof corresponding to parts in Fig. 1 have reference numerals which are 100 higher. Resilient projections can grip into the recesses 313 of the contact pins and thus connect the mounting member 140 to the insulator body 130, anchoring the former to the latter. This is effected in that the mounting member is simply passed over the contact pins. In Fig. 10, parts corresponding to those of Fig. 9 have the same reference numerals. The lamp vessel has a mirroring coating 113 at one side of a plane through the axis 121 so that the lamp radiates light mainly in a lateral direction. The mounting member 240 comprises a first part 241 (Figs. 10b and c) and a second part 242 (Figs. 10d and e). The first part 241 is passed into the second part 242 according to the arrow Xe in Fig. 10d, with a collar 243 against a stop 244. The first part keeps the second part fixed owing to the coupling to the contact pins, by which the first part is rigidly connected to the insulator body 130. Cooperating means: projections 245 and a ribbed rim 246 give the parts a comparatively strong resistance to rotation in a number of rotational positions. The projections 245 are positioned in a resilient manner on bent tongues 249. Hooks 247 at these tongues grip behind a rim 248, which facilitates handling of the mounting member during assembly with the unit. When the second part 242 is rigidly connected to the surroundings, the first part 241 can be rotated along with the rest of the lamp in order to bring the lamp vessel 1 into the desired position.

Claims: A capped electric lamp for operation at mains voltage comprising: a lamp vessel (1) which is sealed in a vacuumtight manner and which at an end portion (2) thereof is fused to a tube (3) which projects into the lamp vessel and which surrounds an exhaust tube (4); an electric element (5) in the lamp vessel (1) connected to current supply conductors (6) which issue to the exterior alongside the exhaust tube (4); a lamp cap (10) provided with a shell (20) having an axis (21), a first end (22) of which shell is fixed around the said end portion (2) of the lamp vessel (1) with an adhesive compound (11), and a second end (23) of which is coupled to an insulator body (30); contact pins (31) fixed in the insulator body (30) and issuing to the exterior therefrom, and connected to respective current supply conductors (6); characterized in that the insulator body (30) has for each of the current supply conductors (6) a narrowing channel (34) which issues near a corresponding contact pin (31) at the location where the latter projects from the insulator body (30) to the exterior, through which channels (34) the current supply conductors (6) extend to outside the insulator body (30) where they are connected laterally to respective contact pins (31), and in that a mounting member (40) made of synthetic resin is connected to the insulator body (30), from which member (40) only the contact pins (31) project to the exterior. A capped electric lamp as claimed in Claim 1, characterized in that the mounting member (40) has a projecting sheath (41) from which the contact pins (31) issue to the exterior. A capped electric lamp as claimed in Claim 1 or 2, characterized in that the contact pins each have a widened portion (33) which is to butt against a surface (42) of the mounting member facing towards the insulator body. A capped electric lamp as claimed in Claim 1 or 2, characterized in that the mounting member (50, 60) comprises resilient tongues (54, 64) curved in a hairpin shape, which tongues each have a free end with a wedge-shaped thicker portion (55, 65) and extend alongside the axis (21) of the shell (20) to beyond a location where they project from the mounting member (50, 60). A capped electric lamp as claimed in Claim 1 or 2, characterized in that the mounting member (40, 50, 60) has an upright rim (46, 56, 66) in which the insulator body (30) is accommodated. A capped electric lamp as claimed in Claim 1, characterized in that the adhesive compound (11), the insulator body (30), and the mounting member (40) fully separate the current supply conductors (6) from one another starting from the end portion (2) of the lamp vessel (1). A capped electric lamp as claimed in Claim 1 or 2, characterized in that the insulator body (30) is made of synthetic resin and the shell (20) is a metal ring and has at its second end (23) an inwardly flanged rim (24) which cooperates with a collar (35) at the insulator body. A capped electric lamp as claimed in Claim 1 or 2, characterized in that the contact pins (31) each have a recess (313) and the mounting member (140) has resiliently provided projections (147) which grip into corresponding recesses (313), keeping the mounting member (140) fixed, connected to the insulator body (130). A capped electric lamp as claimed in Claim 8, characterized in that the mounting member (140) comprises a first part (141) which is rigidly connected to the insulator body (130) and which is rotatably held by a second part (142), keeping the second part coupled to the first part (141). A capped electric lamp as claimed in Claim 9, characterized in that the first (141) and the second (142) part of the mounting member (140) have cooperating means (245, 246) which provide fixation against rotation in several rotational positions.

Inventors: BORGIS LIVIO, PIACIBELLO MARCO VINCENZO PIET, BORGIS, LIVIO, PIACIBELLO, MARCO VINCENZO PIETRO
Applicants: PHILIPS ELECTRONICS NV, PHILIPS ELECTRONICS N.V.
Application year: 1992
Main classification: H01J5
IPC codes: H01J5, H01K1