Patent Application
20070108882
The present disclosure relates to an incandescent lamp and more particularly to an incandescent lamp including a self-sealing mounting base. It finds particular application in the automotive industry for use in a fog lamp. However, it is to be appreciated that the present invention is also amenable to other like environments and applications.
A typical fog lamp assembly includes a light source or lamp located at a focus of a reflector so that light emitted from the light source is directed through a lens of the assembly to achieve a predetermined beam pattern. Generally, the lamp assembly uses a halogen light source.
The light source is typically fixed onto a base and mounted to the lamp assembly. The base and the light source mounted thereon form a replaceable bulb. In order for the lamp to be acceptable to the average consumer, it must be cost competitive relative to other similar lamp assemblies and must also be reliable. Therefore the replacement bulb must be of a construction with few parts for ease of assembly, quality and cost reasons. Proper alignment and stability of the light source inside the lamp assembly are important requirements for the performance of the lamp. The light source must be aligned in a specific position with respect to the base. Once aligned and precisely locked in the appropriate position with respect to the base, the bulb must remain in that aligned position during use for acceptable performance of the lamp assembly.
There is a need for increased stability in association with a replacement lamp, as well as providing a twist and lock arrangement that eliminates the need for a retaining ring, in combination with assured optical capabilities. Heretofore, known arrangement have addressed one or the other of these problems. A need exists to provide a replaceable lamp that has superior optical capabilities, OEM quality, and can be economically sealed to a reflector housing.
Generally, a gimbal device is one of the mechanisms used to align the light source with respect to the plastic base. The gimbal, which serves as a holder for the lamp may also be required to insulate the plastic base from the heated bulb. The gimbal is generally contained within a cylindrical opening in the plastic base from which the light source can be aligned, after which the gimbal is attached to the plastic base by either thermal or mechanical means so as to secure the lamp in the aligned position.
While some prior art replaceable lamp designs and constructions are satisfactory, it is desirable to develop continued improvements and alternative designs for replaceable lamps. For example, it would be desirable to simplify assembly and provide a base for reliability in firmly supporting and aligning the light source, without the need for a gimbal. A replaceable lamp without a gimbal enables the possibility to design the lamp with a shorter light-center-length (LCL) and shorter overall length. This enables a fog lamp reflector with shorter focal length. Short focal length fog lamps are preferred for economical reasons as they require less material to fabricate. Shorter focal length fog lamps also meet the need from vehicle manufacturers to have reduced build-in depth of lighting fixtures at the front end of the vehicle because of the increasing underhood packaging density with emergence of new technologies and safety requirements. Moreover, there is a need to achieve alignment with minimal effort and manipulation by the customer.
Accordingly, the present invention provides a new and improved incandescent lamp including a self sealing mounting base design which overcomes difficulties with the prior art while providing more advantageous overall results.
An incandescent light source finds particular use in a lamp having a reflector is provided. The light source comprises an elongated envelope having a major axis and a filament secured therein such that a major axis of the filament is parallel or offset from the major axis of the envelope. A first fin is secured to the elongated envelope, which supports the envelope against vibrations. Other means of support for the light source of course could be used without departing from the scope of and intent of the subject invention. A base is also connected to the light source. The base includes a body, a flange extending radially from the body, a projection extending axially from the flange, and a twist lock construction capability that incorporates a reference plane perpendicular to the light source filament. To connect the base to the reflector, the projection is dimensioned to extend through an aperture of the reflector and the base is rotated to allow the twist lock to engaging the reflector thereby securing the replaceable bulb to the reflector.
An incandescent light source preferably comprises an envelope having a major axis and an elongated filament received in the envelope such that a major axis thereof is generally aligned with the major axis of the envelope. First and second rigid fins are electrically connected to and extend generally normal from the envelope for supporting the envelope against vibrations. Other means of support for the light source of course could be used without departing from the scope of and intent of the subject invention. A base is electrically connected and secured to the light source. A gasket is attached to the base for sealing the base to a reflector. The gasket has a sealing surface extending in a plane transverse to the major axes and is held in place by the radial flange on the base.
The light source includes an envelope formed from a light transmissive material and has a major axis. An axially extending filament is received in the envelope, a major axis of the filament being offset from the major axis of the envelope. A fin is secured to and extends generally normal from the envelope for supporting the envelope against vibrations. Other means of support for the light source of course could be used without departing from the scope of and intent of the subject invention. The fin electrically interconnects with the filament. A base is secured to the light source, the base including means for sealingly mounting the base to a reflector.
Still other aspects of the invention will become apparent from a reading and understanding of the detailed description of the several embodiments herein below.
With reference to
The elongated envelope 12 includes a first portion 14 forming a sealed cavity and a second portion 16 or press seal base extending therefrom. The first portion 14 is generally cylindrical in cross-section and has a major axis 20. The second portion 16 is generally rectangular in cross-section; although, it should be appreciated that the second portion can have other conformations configured for receipt in a base to be described further below. An end 22 of the first portion 14 can be coated with a non-transmissive material to prevent stray light or glare as is well known in the art.
Contained within the elongated envelope 12 is a filament 30, usually of tungsten. The filament is secured for general alignment with the major axis 20 of the envelope. Specifically, the filament 30 extends axially within the envelope such that a major axis 32 of the filament is generally parallel or offset from the major axis of the envelope 12. Opposing ends of the filament 30 are mechanically secured and electrically connected to first and second lead inner wires 34a, 36a, respectively. The inner lead wires are preferably connected to thin metal foils (not shown), such as molybdenum foils, located in the second portion 16 of the envelope 12. More particularly, the molybdenum foils are mechanically and electrically connected to outer lead wires 34b, 36b that extend outwardly from the press seal base 16 of the lamp envelope.
When energized, the filament 30 emits radiation.
With continued reference to
The first and second lead wires 34, 36 and the first and second fins 40, 42 are mechanically and electrically connected to respective first and second spaced apart leads 60, 62 (
As shown in
With reference to
With reference again to
To assemble the incandescent light source 10, the first and second spaced apart leads 60, 62 are secured to the first and second fins 40, 42 in a well-known manner. Once secured, the major axis 32 of the filament 30 is coincident with a center axis of the projection 110. As such, the center axis of the projection is offset from the major axis 20 of the envelope 12.
To connect the base 70 to the reflector, the projection 110 including the lugs are advanced through a mounting aperture of the reflector such that the bottom surfaces of the lugs are adjacent an inner surface of the reflector. The aperture is dimensioned to allow the base projection to be inserted and rotated to lock into position so that the light source 10 is located at the focus of the reflector. For ease of insertion of the lugs 112, 114, 116 through the reflector aperture, each lug includes a chamfered surface 130, 132, 134. The base 70 is then rotated or twisted to sealingly secure the base to the reflector. Particularly, as the base is twisted, ramps 138, 140, 142 extending from the lugs engage the inner surface of the reflector. This, in turn, further advances the projection 110 relative to the reflector that presses the gasket 118 against an outer surface of the reflector thereby sealing the base to the reflector. The base is rotated until a stop 146 (
Similar to the aforementioned embodiment of the base 70, an additional embodiment of a base 200 is shown in
As shown in
The present disclosure has been described with reference to several embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the disclosure be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
