COMPOSITE HEADLAMP BULB RETAINING MECHANISM

Abstract: This invention is directed to a retaining mechanism for a composite headlamp bulb body (50) that has a seal and a flange (52) with spaced tabs (54) extending therefrom. The mechanism includes a retaining ring (30) which allows the bulb body to be oriented in a predetermined configuration and inserted into the aperture of the retaining ring (30). The retaining ring (30) is snap fitted for permanent installation onto the socket structure of a reflector housing (10) and contains cantilevered finger elements (32) with ramped surfaces to interfere with the flange tabs (54) during rotation of the inserted bulb while in the socket.

Description: The present invention is directed to the field of lighting components and more specifically to the area of retaining mechanisms for composite headlamp bulbs installed in reflector housings. In commonly assigned US-A-4,513,356, a retaining mechanism was described as surrounding both the base flange of a bulb body and a socket opening and locking the bulb body in the socket. The specific embodiment shown in that patent included a threadable collar device with a central aperture for surrounding the bulb body and cantilevered tabs that extended radially inward to compress against the flange when the collar was tightened onto corresponding thread paths formed on the outside of the socket. That mechanism has been widely adopted among manufacturers of composite headlamps utilizing the cylindrical bulb body illustrated in that patent, as well as commonly assigned US-A-4,500,946. More recently, another bulb has become available for use which has a body that is formed with a right angle bend to accommodate an electrical connection that is made transverse to the light axis. This serves to reduce the necessary clearance formerly provided behind the lamp. Such a bulb is illustrated in U.S. Patent 4,631,651, without a described retaining mechanism The present invention provides a retaining mechanism for use with several types of bulbs, but is specifically shown for retaining the type of bulb body described in US-A-4,631,651. In US-A-4 019 045 a retaining ring having an internal flange is fixed to a socket contained in a headlamp reflector, and a bulb having a flange with radial tabs is inserted through a correspondingly shaped aperture in the flange and in the socket and rotated so that the flange is clamped between the tabs on the lamp body and a second flange on the lamp body nearer the base of the lamp. GB-A-2 064 747 discloses a headlamp in which a retaining ring is fitted into an aperture in the reflector by a bayonet type fitting, the bulb envelope is inserted through apertures in the retaining ring and the reflector so that radial tabs extending from a flange on the body of the bulb fit non-rotatably into recesses in the rear face of the retaining ring, and the tabs are clamped against the retaining ring by a plug that is secured to the ring by snap fittings. According to the present invention there is provided a mechanism for retaining a composite headlamp bulb comprising a bulb envelope and a body in a reflector housing, said mechanism including an integral socket structure with an aperture for accepting the bulb envelope and a retaining ring having a central aperture aligned with the aperture of the socket structure for accepting the insertion of the bulb body, is characterised in that the socket structure includes a seat for the bulb body and the retaining ring contains integral locking elements for providing a permanent snap fit to the socket structure and a plurality of cantilevered elements configured to engage with the bulb body on insertion and rotation thereof to removably compress the bulb body against the seat in the socket structure. In an embodiment of the invention the bulb body is formed with a flange having a plurality of tabs extending from its periphery at predetermined positions. the aperture of the retaining ring is configured to be sufficiently large for the flange of the bulb body and its tabs to be inserted through the aperture when properly aligned and oriented. After insertion, the flanged bulb body is rotated through a defined angle and the tabs slide beneath a set of cantilevered retaining fingers that extend into the ring aperture from its periphery, where the flange is thereafter retained against the socket opening in a sealed condition to prevent movement or accidental removal from the socket. The flanged bulb body can be removed from the retaining ring by overcoming the friction of the retaining fingers on the flange tabs, rotating the bulb body in the opposite direction through the same angle and axially withdrawing the bulb body from the socket through the aperture of the retaining ring. The invention provides a retaining ring that is self-latching onto the socket structure so as to eliminate the need for installation tools. The retaining ring can only be latched onto the socket structure in a single orientation and the bulb body can only be inserted into the aperture of the ring in a single orientation and rotated to a second single orientation for retention. The invention will now be described further, by way of example, with reference to the accompanying drawings, in which : Figure 1 is an exploded perspective view of the preferred embodiment of the present invention. Figure 2 is a perspective view of the preferred embodiment shown in a fully assembled configuration. Figure 3 is a partial cross sectional plan view of the preferred embodiment shown in Figure 2. Figure 4 is an underside view of the retaining ring utilized in the preferred embodiment. Figure 5 is an underside view of the retaining ring shown in Figure 4 with the flanged bulb body oriented for insertion from the opposite side. Figure 6 is an underside view of the retaining ring shown in Figure 4 with the inserted flanged bulb body rotated to its fully locked position, and Figure 7 is an exploded view of lighting components embodying the invention. In Figure 1, a sealable reflector housing 10 is shown having a socket aperture 20 and associated structure formed therein to receive an O-ring sealable bulb body therein. The socket structure forming the aperture 20 includes a circular sidewall of a diameter appropriate for receiving and compressing the O-ring 53 on the body 55 of bulb 50. A larger diametered opening 18 is shown as being concentric with the socket aperture 20 and serves to define the seating surface 19 intermediate thereof. The seating surface 19 is that surface to which the flange 52 of the bulb body 55 is compressed against by the retaining ring 30 when the bulb body is inserted and rotated for locking. A flange 12 is formed to extend outward from sidewall 18 and is raised from the housing 10 to provide a gripping edge for the retaining ring 30 (see Figure 3). The bulb 50 is shown in Figure 1 as supported in a bulb body 55 by a clip element 51. The bulb preferrably contains one or more filaments that are electrically connected through the body 55 to an electrical connector 57 located at the opposite end of the body 55. (Details of the internal electrical connections and support clip element are described in the prior art and are not described herein.) The body 55 is formed to have a right angle bend so that electrical connections are made at connector 57, transverse to the socket axis. The body 55 also contains a substantially circular flange 52 and a plurality of tabs 54′, 54″ and 54‴ radially extending therefrom. In the preferred embodiment, the flange tabs 54′, 54″ and 54‴ are inconsistently sized so that the bulb body 55 may be inserted in the socket in a single orientation. Such a single orientation feature is extremely important in the situation where the present invention is employed in automotive headlamp applications. In such applications, there is a strict requirement that the filaments of the bulbs be precisely oriented and postioned within their associated reflectors to provide a prescribed lighting pattern. With common reference to Figures 1-6, the retaining ring is now described. The retaining ring 30 is preferrably formed of a molded plastic material so that its aligning and locking features may be combined in a unitary structure. The retaining ring 30 is circular cup shaped with an cylindrical side wall 33 having an inner diameter that is slightly larger than the diameter of the raised flange 12 on the reflector housing 10. A plurality of ramped catch barbs 34 are formed to coextend from the side wall 33. The ramp portions of the catch barbs 34 extend inside the inner diameter dimension of the side wall 33 so as to contact the outer lip 14 adjacent the raised flange 12, when installed thereon. An alignment hole 36 is located on the retaining ring 30 to coincide with the alignment pin 16 extending from the socket structure on the reflector housing 10. Therefore, when the retaining ring 30 is installed on the housing 10, the pin 16 is first aligned with the alignment hole 36. Secondly, the ramps of the catch barbs 34 are each positioned to contact the outer lip 14 and the ring is axially forced against the housing 10 until all the catches 34 snap in place behind the raised flange 12. At this point, the retaining ring is permanently installed on the housing 10 and is only removable if several of the catches 34 are forced outwardly from the raised flange 12. The retaining ring 30 contains a generally circular aperture that is axially aligned with the socket aperture 20 and has a clearance diameter defined by projecting cantilevered finger elements 32′, 32″ and 32‴. The clearance diameter is sized to allow the flange 52 of the bulb body 55 pass through, unobstructed. The respective cantilevered finger elements 32′, 32″ and 32‴ contain ramped surfaces 38′, 38″ and 38‴ on the socket side of the ring 30, opposite the insertion direction of the bulb body 55. The ramped surfaces extend sufficiently towards the seating surface 19 so that the distance therebetween is less than the thickness of the flange tabs 54′, 54″ and 54‴ of the bulb body 55. Compression surfaces 40′, 40″ and 40‴ are also formed adjacent the ramped surfaces on the respective cantilevered finger elements 32′, 32″ and 32‴ so as to provide continuous holding of the flange tabs 54′, 54″ and 54‴ against the seating surface 19, when the bulb body 55 is installed. When viewed in Figure 5 from the socket side of the retaining ring 30 with the bulb body 55 oriented for insertion through the central aperture, the flange tab 54′ is oriented to pass through the space 39′ defined between cantilevered finger elements 32′ and 32‴. Similarly, spaces 39″ and 39‴ are also provided to respectively pass flange tabs 54″ and 54‴. As mentioned above, the flange tabs are of various sizes to insure a predetermined orientation. Consequently, the spaces between the cantilevered finger elements are of corresponding sizes to profile the flange 52 and its tabs in order to thereby allow the flange 52 and all the tabs to pass through the aperture of the retaining ring 30 when the bulb body 55 is in its proper orientation and alignment with respect to the socket. As can be seen from Figure 6, when the inserted bulb body 55 is rotated through a predetermined angle, the tabs 54′, 54″ and 54‴ cause cantilevered finger elements 32′, 32″ and 32‴ to be deflected away from the socket. When tab 54′ is rotated past an antirotation surface 41, between ramp surface 38′ and compression surface 40′, the tab 54′(and the entire bulb body 55) is frictionally held to prevent accidental rotation from that position. Of course, when removal of the bulb body 55 is desired, it is only necessary to rotate the bulb body 55 in a counter-clockwise direction after overcoming the friction interference caused by the antirotation surface 41 against tab 54′.

Claims: A mechanism for retaining a composite headlamp bulb comprising a bulb envelope (50) and a bulb body (55) in a reflector housing (10), said mechanism including an integral socket structure with an aperture (20) for accepting the bulb envelope and a retaining ring (30) having a central aperture aligned with the aperture (20) of the socket structure for accepting the insertion of the bulb body, characterised in that the socket structure includes a seat (19) for the bulb body and the retaining ring (30) contains integral locking elements (34) for providing a permanent snap fit to the socket structure and a plurality of cantilevered elements (32) configured to engage with the bulb body on insertion and rotation thereof to removably compress the bulb body against the seat (19) in the socket structure. A mechanism as claimed in claim 1, wherein the body (55) of said composite headlamp bulb is formed with a flange (52) having a plurality of tabs (54',54'',54''') extending outwardly of its periphery and said cantilevered elements (32',32'',32''') of said retaining ring (30) are spaced apart by an amount that allows said tabs on said flange to pass through, when inserted in said ring. A mechanism as claimed in claim 2, wherein said retaining ring is permanently mounted on said socket structure and said cantilevered elements (32',32'',32''') contain ramped surfaces (38',38'',38''') respectively disposed to interfere with the rotation of said tabs (54',54'',54''') when said headlamp bulb body is inserted in the aperture in said ring. A mechanism as claimed in claim 3, wherein said cantilevered elements of said retaining ring also contain compression surfaces (40',40''.40''') adjacent said ramped surfaces that provide friction to hold said tabs when said headlamp bulb body is inserted in the aperture in said ring and rotated so that said tabs coincide with said compression surfaces. A mechanism as claimed in any preceding claim, wherein said socket structure contains an outwardly extending flange structure (12) concentric with said socket aperture (20) and said locking elements (34) of said retaining ring (30) are disposed about the periphery of said retaining ring to interfere with said socket structure flange when said ring is aligned therewith and forced onto said socket structure. A mechanism as claimed in claim 5, wherein said locking elements (34) of said retaining ring contain barbed elements that capture the opposite side of said socket flange structure when said ring is forced onto said socket structure for a predetermined distance. A mechanism as claimed in any preceding claim, wherein said socket structure and said retaining ring (30) contain complementary means (16,36) for aligning said retaining ring with respect to said socket structure aperture (20) prior to engaging said locking elements (34) against said socket structure. A mechanism as claimed in claim 7, wherein said complementary aligning means includes a pin element (16) and a correspondingly sized hole (36) on said socket structure and said retaining ring, respectively. A mechanism as claimed in claim 8, wherein said socket structure contains said pin element (16) aligned parallel with the socket aperture (20) and said retaining ring contains a correspondingly sized hole (36) to accept said pin element when the two are axially aligned.

Inventors: BRADLEY, HUGH THOMAS
Applicants: FORD FRANCE SOCIETE ANONYME, FORD MOTOR COMPANY, FORD MOTOR COMPANY LIMITED, FORD-WERKE AKTIENGESELLSCHAFT
Application year: 1988
Main classification: F21M7
IPC codes: F21S8, H01R33, F21V19