Apparatus for holding the cover of a lamp assembly of a vehicle

Abstract: An apparatus of holding a rubber or elastic cover (10) covering a bulb exchange opening of a lamp assembly of vehicle. The apparatus comprises a holder (2) defining the bulb exchange opening and having a plurality of outer engagement claws (2a) formed at predetermined intervals in the circumferential direction, and a cap (3) retaining the cover together with the holder. The cap (3) has a plurality of hooks (3a) engaging the claws (2a) when the cap (3) is rotated for engaging the holder (2). The apparatus further comprises at least one cap abutment (4) provided on the holder (2) at a circumferential position of the holder (2) between adjacent two claws (2a), which interferes in the direction of engagement between the cap (3) and the cap abutment (4) when the cap (3) is mounted on the holder (2). Thereby the apparatus gives a sensible physical response to an operator for confirming the right engagement of the cover (10), the cap (3) and the holder (2), and reliably enhances the holding function.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention An apparatus for holding an elastic cover which is mounted on its rear side on a cylindrical holder for covering a bulb exchange opening of a lamp assembly, said cylindrical holder defining the bulb exchange opening and having a plurality of outer engagement claws formed at predetermined intervals in the circumferential direction, and a cap retaining the cover together with said holder, said cap having a plurality of hooks engaging the outer engagement claws when said cap is rotated in mounting the cover on said holder. 2. Background Art FIG. 3 shows a prior-art apparatus of holding a rubber cover 80 on a hollow cylindrical holder 91 of a lamp assembly of vehicle, as it is known from e.g. the Japanese Utility Model Laid-open Publications Nos. 3-40706, 3-77304 and 3-100301. The holder 91 defines a bulb exchange opening and has outer engagement claws 91a formed at its plural (e.g. three) circumferential positions. The lamp assembly 90 comprises a separate cap 92 having hooks 92a engageable with the outer engagement claws 91a. In mounting, an outwardly extending flange 80a of the cover 80 is in contact with the rear edge surface of the holder 91, the cap 92 is then place over the holder 91 to sandwich the flange 80a of the cover 80 with the rear edge surface of the holder 91, and the cap 92 is then rotated for engaging the hooks 92a with the outer engagement claws 91a of the holder 91. Each of the hooks 92a has a tapered portion 92b and a concavely stepped portion 92c so that the cap 92 forcibly presses the flange 80a between the cap 92 and the holder 91 as an operator rotate the cap 92. Thereby the apparatus secures a tight seal of the interior of the lamp assembly against rain or water. Further, when the outer engagement claws 91a reach the concavely stepped portions 92c, fingers of the operator feels a physical response by which he or she realizes that the cap 92 has been set in place. The concavely stepped portions 92c also prevent the cap 92 from rotating in the reverse direction in service of the lamp assembly 90 to increase reliability of the function of the cap 92 of retaining the cover 80 on the holder 91. In the prior-art apparatus, the retention of the cap 92 on the holder 91 and the physical response of the operator are attributed to elasticity of the flange 80a of the rubber cover 80. Therefore, if the cover 80 loses elasticity due to aging, then the operator feels no physical response in mounting the cover 80 on the holder 91, and the cap 92 cannot securely retain the cover 80 on the holder 91. Thus reliability of the holder 91 and the cap 92 in retaining the cover 80 in rain-tight decreases. The solution of such problem therefore has been desired. The EP-0 300 482 A3 discloses an automotive lamp assembly having a housing in which a bulb and reflector are disposed, and a rear cover sealing the housing rear thereof. It also has a cover holder which is fitted to the housing from outside the rear cover, namely, with the rear cover held between the housing rear and the cover holder. The rear cover is fixed in place on the housing by means of the cover holder. The rear cover has a means which works with the cover holder and the housing to provide a sealing between the housing and the rear cover, and also a means for blocking an air under pressure flowing from the housing inside outwardly of the lamp assembly through the clearance between the rear cover and the housing when the bulb is tumed on, thereby maintaining the sealing against any water going to enter from between the housing and the rear cover. The DE-A1-35 43 080 discloses a protective cap being mounted on the rear side of a reflector integrated in a lamp assembly. The protective cap comprises a sleeve having hooks arranged in its interior, these hooks co-acting with a flange of the light assembly and a resilient seal. SUMMARY OF THE INVENTION An object of the present invention is to provide an improved apparatus for holding an elastic or rubber cover which is mounted on a holder of a lamp assembly of vehicle for holding a bulb rain tight. The invention comprises of at least one cap abutment which is provided on said holder between positions of adjacent two of the outer engagement claws so that said cap and said cap abutment interfere with each other for elastic deformation of said cap when said cap is mounted on said holder. As described above, the apparatus has the cap abutment for biassing the cap in the direction of engagement between the outer engagement claws and the hooks, so that a predetermined amount of partial deformation of cap is produced when the outer engagement claws engage the hooks. Therefore, the apparatus can produce a sensible physical response of an operator while maintaining the holding function, even when elasticity of the rubber cover decreases due to ageing. In this structure, the present invention solved the above problems and successfully enhanced reliability of the apparatus. Other objects , features and advantages of the present invention will be apparent from a consideration of the following description, taken in connection with the accompanying drawing. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 is an exploded perspective view of an apparatus of holding a rubber cover of a lamp assembly of vehicle according to an embodiment of the present invention; FIG.2 is an explanatory scheme illustrating the mechanism of the apparatus of FIG.1; FIG.3 is a sectional view of a prior-art apparatus of holding a cover of a lamp assembly of vehicle; and FIG.4 is an enlarged sectional view of a major part of the apparatus of FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described with reference to the drawings hereinafter. As shown in FIG.1, a lamp assembly of vehicle comprises a cylindrical holder 2 defining a bulb exchange opening. The holder 2 may be made of a synthetic resin of a slight elasticity. The holder 2 has outer engagement claws 2a protruding radially from a rear flange of the holder 2 at plural (e.g. three) circumferential positions. The lamp assembly 1 further comprises a cylindrical cap 3 having hooks 3a engageable with the outer engagement claws 2a. The cap 3 may be made of a synthetic resin of a slight elasticity. A rubber or elastic cover 10 is mounted on the holder 2 with a flange 11 thereof held between the holder 2 and the cap 3. The holder 2 has one or more, preferably, three cap abutments 4 formed at its circumferential positions. Each of the cap abutments 4 is located between two adjacent outer engagement claws 2a at such a radial position that the cap abutments 4 engage the front edge surface 3b of the cap 3 when the cap 3 is mounted on the holder 2. Next, a detailed explanation will be given regarding the positional relationship between the cap abutments 4 and the cap 3. The height of the cap abutments 4 is so designed that the front edge surface 3b of the cap 3 interferes for elastic deformation with the cap abutments 4 in service of the lamp assembly 1. The amount of the interference or deformation is referred to as a distance in the direction of engagement (direction of thickness of the outer engagement claws 2a) between an upper surface of each of the cap abutments 4 and a theoretical position of the front edge surface 3b of the cap 3 in service of the lamp assembly 1, assuming that the cap abutments 4 do not exist. Hereinafter, such distance is referred to as "amount of interference". The most preferable result is obtained when the amount of interference is 0.2-0.3 mm. FIG.2 is an explanatory scheme of the structure of the apparatus showing the mounting of the cap 3 on the holder 2. When the cap 3 is rotated to engage the hooks 3a with the outer engagement claws 2a as shown in FIG.2, the cap 3 is partially deformed to curve downward at locations corresponding to the positions of the hooks 3a. This produces a resistance in rotating the cap 3, thereby giving a sensible physical response to fingers of the operator. The cap abutments 4 enable the combination of the holder 2 and cap 3 to produce a sensible physical response which indicates the right engagement of the cap 3 and the holder 2, and establish a secure holding of the cover without use of elasticity of the cover. Accordingly, it is possible to give a physical response of the right engagement of the cap 3 and the holder 2 to the operator to securely hold the cover even when the elasticity of the cover decreases due to aging. In the above embodiment, the cap abutments are arranged for the engagement with the front edge surface of the cap. However, the position and height of the cap abutments may be modified in such a way that the cap abutments engage a different portion of the cap, e.g., the inner surface of the rear portion of the cap, or extensions from the circumferential surface of the cap. Although the apparatus of the above embodiment has three cap abutments, similar effects can be obtained by providing one or two cap abutments. The present invention is not rigidly restricted to the embodiments described above. It is to be understood that a person skilled in the art can easily change and modify the present invention without departing from the scope of the invention defined in the appended claims.

Claims: An apparatus for holding an elastic cover (10) on the rear of a cylindrical holder (2) for covering a bulb exchange opening of a lamp assembly (1), said cylindrical holder (2) defining the bulb exchange opening and having a plurality of outer engagement claws (2a) formed at predetermined intervals in the circumferential direction, and a cap (3) for retaining the cover on said holder (2), said cap (3) having a plurality of hooks (3a) for engaging the outer engagement claws (2a) when said cap (3) is rotated in mounting the cover (10) on said holder; characterised by at least one cap abutment (4) provided on said holder (2) between positions of adjacent two of the outer engagement claws (2a) so that said cap (3) and said cap abutment (4) interfere with each other for elastic deformation of said cap (3) when said cap (3) is mounted on said holder (2). The apparatus according to claim 1, characterized in that said cap abutment (4) is provided at a center of said adjacent two outer engagement claws (2a). The apparatus according to claim 2, characterized in that said cap abutment (4) is provided at such a radial position that the bottom end surface (3b) of said cap (3) engages said cap abutment (4). The apparatus according to claim 3, characterized in that the height of said cap abutment (4) is determined so that an interference of 0.2-0.3 mm in the direction of engagement is produced between said cap (3) and said cap abutment (4) when said cap (3) is mounted on said holder (2). The apparatus according to claim 3, characterized in that said holder (2) has three of the outer engagement claws (2a), said cap (3) has three of the hooks (3a), and said apparatus (1) has three corresponding cap abutments (4).

Inventors: ITO RYOJI, NARUMI YOSHITAKA, ITO, RYOJI, NARUMI, YOSHITAKA
Applicants: STANLEY ELECTRIC CO LTD, STANLEY ELECTRIC CO., LTD.
Application year: 1993
Main classification: F21M7
IPC codes: F21V19, F21V31, F21S8, F21V17