Illumination – Supported by vehicle structure – Specific lamp mounting or retaining
Reexamination Certificate
2000-05-30
2002-06-25
Husar, Stephen (Department: 2875)
Illumination
Supported by vehicle structure
Specific lamp mounting or retaining
C362S229000, C362S263000, C362S267000, C362S296040, C313S318010, C313S318110
Reexamination Certificate
active
06409372
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a capped electric lamp provided with:
a light-transmitting lamp vessel which is closed in a gastight manner, which has an axis, and in which an electric element is arranged having a center and connected to current conductors which issue from the lamp vessel to the exterior;
a lamp cap connected to the lamp vessel, which lamp cap comprises a housing;
said housing being provided with:
contact members which are connected to the current conductors;
at least a reference means;
at least a locking means for locking the connection between the lamp vessel and the lamp cap; and
at least a coupling means.
BACKGROUND OF THE INVENTION
Such a capped electric lamp is known from EP-A-0 618 609. The known lamp is provided with a pressure body to which the lamp vessel is coupled. The pressure body is coupled to the housing by means of a snap connection, said housing having a circumferential wall extending parallel to the axis. A separate elastic body, for example a rubber disc or ring, is accommodated between the pressure body and the housing, as seen in axial direction. A permanent force obtains between the housing and the pressure body owing to the elasticity of the disc or ring, so that the pressure body with the lamp vessel connected thereto remains correctly positioned with respect to the housing. A number of functional units of the lamp cap such as contact members, reference means, and coupling means, are present axially displaced relative to one another. This means that the lamp has a comparatively great constructional height in axial direction.
The known lamp is suitable for being mounted in a reflector. The lamp has a projecting collar which is provided with studs which co-operate with the reflector and by means of which the lamp cap and the reflector are coupled to one another in a rotary movement. The known lamp is highly suitable for use as a vehicle headlamp.
Car set makers require that the actions to be performed in the assembly of car components, for example lighting units for vehicles, are as simple as possible. A further wish is that the car components should be universally applicable and uniform, i.e. independent of the assembling method, such as in the case of lamps, for example, the plate, front, and back mounting methods. The known lamp should accordingly be designed for any mounting method as desired, bulb forward (back/plate mounting) or lamp cap forward (front mounting) against a support. The lamp is then held by additional means on the support, such that the electric element occupies a predetermined position with respect to this support.
A disadvantage of the known capped lamp is that it is not universally applicable owing to the comparatively large and highly asymmetrical lamp cap, for example that it is unsuitable for front mounting. A second disadvantage is the cumbersome assembly of the lamp and the lighting unit, on the one hand owing to the comparatively large number of loose components and on the other hand on account of the comparatively complicated rotary movements necessary for coupling the lamp cap to the reflector. A third disadvantage is that tolerances in the dimensions of the housing and the pressure body are compensated for by the elastic ring to a limited degree only. This means that there is a considerable risk that the housing and the pressure body bear upon one another without a permanent spring pressure, so that the housing and the pressure body can become displaced relative to one another, with the result that the electric element will no longer be correctly aligned with respect to the support.
A capped electric lamp is known from DE-B-1 034 268 where the glass bulb of the lamp is closed off by a plate of insulating material, which plate lies in a plane which is at least substantially perpendicular to the axis. A hollow cylindrical lamp cap is fixed at the side of the plate facing away from the bulb in a manner not described in any detail. The known bulb, however, is only designed for back and plate mounting. It is desirable for various applications, however, to have a lamp available which can be placed against a support with its lamp cap forward.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a capped electric lamp of the kind described in the opening paragraph which is of a simple, easily manufactured construction and which counteracts the above disadvantages.
According to the invention, this object is achieved in that the coupling means forms an integral whole with the housing in that they share an integral, resilient intermediate portion. Since the lamp cap does not comprise loose components but is made from one piece, it has the advantage of a simple lamp assembly and at the same time renders possible a more compact lamp with smaller constructional dimensions. In the mounted state, the resilient intermediate portion is in a non-relaxed state, so that there is a permanent spring pressure between the coupling means and the reference means. The reference means and the coupling means thus remain in a fixed position relative to one another in the mounted state. The lamp is universally applicable because the compact lamp cap is comparatively small compared with the lamp vessel. A difference in stiffness of the resilient action of the resilient intermediate portion can be realized in a simple manner by means of thickness variations and the choice of material for the resilient intermediate portion. It is thus easy to realize a desired value of the permanent resilient force exerted between the lamp cap and a support coupled thereto, for example a reflector or an adapter, via the reference means, which is formed, for example, by studs or surfaces. It was found that a force equal to twice the force of gravity is sufficient for keeping the lamp positioned under normal practical conditions involving shock and impact loads.
In an embodiment, the lamp is characterized in that the resilient intermediate portion is displaceable around the housing in a substantially axial direction. The axial displaceability of the resilient intermediate portion around the housing may be achieved, for example, in that the resilient intermediate portion is provided with an internal dimension which, seen in one and the same plane, is greater than an external diameter of the housing. It is advantageously achieved thereby that the shape of the lamp cap is self-releasing from its mold. The mold can accordingly be free from moving parts, and the lamp cap can accordingly be manufactured in a comparatively simple and inexpensive manner.
The problem referred to as “black gap”, known to those skilled in the art, may arise when the capped lamp is used as a vehicle lamp in a lighting unit. The black gap is visible as a dark ring around the luminous lamp vessel during operation of the lighting unit, which ring is surrounded by the light reflected by the reflector and originating from the electric element. The black gap is caused by light losses which occur when light originating from the electric element is incident on the lamp cap. The favorable situation in which the guidelines for counteracting the black gap problem in lighting units of vehicles are complied with is obtained in an embodiment which is characterized in that the lamp cap falls at least substantially completely within a cone having an apex in the center of the electric element and a half apex angle of at most 25°.
In a further preferred embodiment, the housing comprises a flat base portion which is at least substantially perpendicular to the axis. This base portion serves as an abutment for the placement of the lamp vessel in the lamp cap. The lamp vessel is closed in a gastight manner by means of a plate of insulating material which lies in a plane which is at least substantially perpendicular to the axis. In the manufacture of the lamp according to the invention, the electric element is mounted in a predetermined position relative to the plate of insulating material. The plate of the lamp vessel bears on the base portion of the lamp cap with a permanent
Manders Wilhelmus Johannes Maria
Peters Ralph Hubert
Van Dulmen Hendrikus Albertus Maria
Halajian Dicran
Husar Stephen
Koninklijke Philips Electronics , N.V.
Lee Guiyoung
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