Illumination – Plural light sources – Diverse light generators
Reexamination Certificate
1999-03-26
2001-04-03
Sember, Thomas M. (Department: 2875)
Illumination
Plural light sources
Diverse light generators
C362S263000, C313S318010, C313S318110
Reexamination Certificate
active
06210020
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a capped electric lamp provided with:
a translucent lamp vessel which is closed in a gastight manner, which has an axis, and in which an electric element is arranged, said element having a center and being connected to current conductors which issue from the lamp vessel to the exterior;
a lamp cap connected to the lamp vessel and comprising a housing;
which housing is provided with:
contact members connected to the current conductors,
at least one reference means,
at least one locking means for locking the connection of the lamp vessel to the lamp cap, and
at least one coupling means.
Such a capped electric lamp is known from EP-A-0 618 609 to which U.S. Pat. 5,479,066 corresponds. 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, the housing having a circumferential wall which runs parallel to the axis. A separate elastic body, for example, a rubber disc or ring, is arranged between the in pressure body and the housing, as seen in axial direction. The elasticity of the disc or ring causes a permanent force to be present between the housing and the pressure body, so that the pressure body with the lamp vessel coupled thereto remains correctly positioned with respect to the housing. A number of functions of the lamp cap, such as contact members, reference and coupling means, are present in positions which are axially shifted relative to one another. As a result, the lamp has a comparatively large constructional dimension in the 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 cooperate with the reflector and by means of which the lamp cap and the reflector can be coupled to one another in a rotary movement. The known lamp is very suitable for use as a vehicle headlamp.
It is a wish of car manufacturers that the actions to be performed in the assembly of car components, such as, for example, lighting units for vehicles, should be as simple as possible. A further wish is that car components should be universally applicable and uniform, i.e. independent of the assembling method, in the case of lamps, for example, plate, front, and back mounting. The known lamp should accordingly be designed for mounting against a support with the bulb forward (back/plate mounting) or with the lamp cap forward (front mounting), as desired. The lamp will then be retained on the support by additional means, while the electric element occupies a previously defined position with respect to this support.
It is a disadvantage of the known capped lamp that it is not universally applicable owing to the comparatively large and highly asymmetrical lamp cap, for example, it is unsuitable for front mounting. A second disadvantage is the difficulty of assembly of the lamp with the lighting unit, on the one hand owing to the comparatively large number of loose components and on the other hand owing to 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 accommodated to a limited degree only by the eleastic ring. This involves a considerable risk that the housing and the pressure body bear upon one another without a permanent resilient pressure, so that the housing and the pressure body can move relative to one another and the electric element will be no longer correctly aligned with respect to the support.
DE-B-1 034 268 discloses a capped electric lamp whose glass bulb is closed with a plate of insulating material which lies in a plane which is at least substantially perpendicular to the axis. A hollow cylindrical lamp cap is fixed to 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 assemblies with back/plate mounting. It is desirable for various applications, however, to have a lamp available which can be placed against a support with the 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 construction which can be readily manufactured and which counteracts the above disadvantages.
According to the invention, this object is achieved in that the coupling means forms part of the housing via an integral, resilient intermediate portion. Since the lamp cap comprises no loose components but is made as one integral whole, it offers the advantage of a simple lamp assembly, while at the same time rendering possible a more compact lamp with a smaller constructional dimension for incorporation. The resilient intermediate portion in the mounted state will be in a non-relaxed state, so that there will be a permanent resilient pressure between the coupling means and the reference means. As a result, the reference means and the coupling means will remain in fixed positions relative to one another in the mounted state. The lamp is universally applicable because the compact lamp cap is comparatively small in comparison with the lamp vessel.
In a favorable embodiment, the resilient action of the intermediate portion is obtained in a simple manner by means of a void which extends over substantially an entire cross-sectional area of the intermediate portion. The remaining portion of the cross-sectional area then forms a bridge. The void in the intermediate portion may be provided in various directions, for example parallel to the axis or at an angle to the axis, or, for example, perpendicular to the axis, whereby the resilient action is obtained in a very effective manner because the displacement in the case of resilience here is at least substantially in axial the direction only.
Variation of the number of voids and the dimension of the voids in the axial direction renders possible a simple adjustment of, on the one hand, the relative displacement possibility of the resilient intermediate portion with respect to the housing and, on the other hand, the value of the resilient force which can be realized. A difference in stiffness of the resilient action can be realized in a simple manner in that not one but, for example, two mutually opposed bridges are maintained which lie in one and the same plane perpendicular to the axial direction. A desired value of the permanent resilient force exerted by the lamp cap and a support, for example, a reflector or an adapter, coupled thereto via the reference means, for example in the form of studs, on one another can thus be readily realized. It was found that a force equal to twice the force of gravity is sufficient for keeping the lamp positioned under usual practical circumstances as regards shock and impact loads.
In a favorable embodiment, the contact members, reference means, and coupling means occupy positions which are mutually rotated about the axis and which lie in a common plane transverse to the axis. The capped lamp according to the invention thus has a smaller constructional dimension in the axial direction than a capped lamp in which the various means are positioned in axial direction next to one another. The housing in which the lamp is to be accommodated can be comparatively flat thanks to the comparatively small dimension in axial direction.
When the capped lamp is used as a vehicle lamp in a lighting unit, the “black gap” problem known to those skilled in the art may arise. The black gap is visible during operation of the lighting unit as a dark ring around the illuminated lamp vessel, which ring is surrounded by the light reflected by the reflector, said light originating from the electric element. The black gap is the result of light losses which occur when light originating from the electric element hits the lamp cap. In an embodiment in which the lamp cap lies at least substantially within a cone with an apex in the center of the electric element and with an ape
Manders Wilhelmus J. M.
Peters Ralph H.
Van Dulmen Hendrikus A. M.
Halajian Dicran
Sember Thomas M.
U.S. Philips Corporation
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