Patent Publication Number: US-6905230-B2

Title: UV lamp retainer system

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to ultraviolet (UV) curing systems, and more particularly to a retainer for supporting a UV lamp in a UV lamp system. 
   BACKGROUND OF THE INVENTION 
   UV cure systems are widely used in industry to cure inks, paints, adhesives and coatings by ultraviolet radiation. Several types of UV lamps systems are available. One commonly used system utilizes mercury arc lamps to generate the necessary ultraviolet radiation. These lamps generally comprise a quartz bulb containing an electrically excitable gas, such as mercury, sealed within the bulb. The bulb is sealed by insulating end caps which also contain electrodes for electrically exciting or ionizing the gas to create and sustain a high voltage arc. Mercury arc lamps are typically supported in a lamp assembly by spring clips, whereby the lamp may be easily removed and replaced as required. The clips are shaped to engage the lamp and to support it at a desired location within the lamp assembly. Mercury arc lamps are generally used with a reflector which helps to direct the UV energy emanating from the lamp to a substrate surface which is to be cured, dried, or otherwise affected by the energy. 
   In order to optimize curing efficiency, it is important to accurately position the mercury arc lamp with respect to the reflector and to the substrate. One drawback of prior UV lamps systems has been the difficulty associated with accurately positioning the bulb. Even when the bulb is initially installed in the correct position, the flexibility of supporting components often fail to maintain accurate positioning of the bulb, especially when exposed to the high heat generated by the UV lamp. This problem is particularly troublesome for lamp assemblies which are fabricated from sheet metal components. Accordingly, there is a need for a device for accurately positioning a UV lamp within a lamp assembly which overcomes drawbacks of the prior art such as those discussed above. 
   SUMMARY OF THE INVENTION 
   The present invention provides a lamp retainer that facilitates removal and installation of a UV lamp in a UV lamp system, to permit easy replacement of the UV lamp, while ensuring accurate and repeatable positioning of the lamp within a UV lamp housing. In one aspect of the invention, the lamp retainer includes a retainer bracket having a registration surface configured to engage a UV lamp and to provide a positive location for positioning the lamp with respect to the lamp housing and a reflector mounted within the housing. A retainer clip coupled to the bracket is configured to engage the lamp and bias the lamp toward the registration surface. 
   In an exemplary embodiment, the registration surface is defined by an aperture formed in the retainer bracket. The retainer clip is secured to the retainer bracket, adjacent the aperture. Opposing clip fingers of the retainer clip engage ceramic end caps of the lamp and urge the end caps into engagement with the registration surface. 
   In another aspect of the invention, a UV lamp system comprises a support member, a lamp reflector coupled to the support member, a lamp retainer, and a UV lamp. The lamp retainer includes a registration surface configured to ensure accurate positioning of the lamp with respect to the reflector, and a retainer clip for biasing the lamp into engagement with the registration surface. 
   These and other objects, advantages, and features of the invention will become more readily apparent to those of ordinary skill in the art upon review of the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention. 
       FIG. 1  is an elevation view of a UV lamp system including a lamp retainer according to the present invention; 
       FIG. 2  is a cross-sectional view of the lamp system of  FIG. 1 , taken along line  2 — 2 ; 
       FIG. 3  is a perspective view of the exemplary lamp retainer of  FIGS. 1-2 ; 
       FIG. 4  is a perspective view of a support bracket of the retainer depicted in  FIG. 3 ; and 
       FIG. 5  is a perspective view of an exemplary clip of the lamp retainer depicted in FIG.  3 . 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , there is shown an exemplary UV lamp system  10  including a UV lamp  12  supported in a housing  14  by an exemplary retainer assembly  16  in accordance with principles of the present invention. The housing  14  is configured to receive and support the components of the lamp system  10 . In the exemplary embodiment shown, the housing  14  includes spaced vertical housing walls  18  and laterally extending housing support members  20  disposed on oppositely facing sides of the vertical walls  18 . A lamp reflector  22  is secured to the housing  14 , generally between the vertical walls  18  and is configured to reflect UV light emanating from the lamp  12  and direct it toward a substrate material (not shown) to be cured, dried, or otherwise affected by the UV light. The lamp  12  comprises an elongate quartz glass bulb  24  sealed at its ends by ceramic end caps  26   a ,  26   b  and containing an electrically excitable gas therein. Electrodes (not shown) positioned at respective ends of the bulb  24  are supported by the ceramic end caps  26   a ,  26   b  and may be coupled to appropriate electrical connectors suitable for powering the lamp  12 . 
   The UV lamp  12  is supported within the housing  14  by a retainer assembly  16 , comprising a retainer bracket  30  configured to define a positive registration feature that accurately positions the lamp  12 , and a retainer clip  32  that engages the lamp  12  and retains the lamp  12  relative to the retainer bracket  30 . Referring now to  FIGS. 2-5 , the lamp retainer  16  will be described in greater detail. The retainer bracket  30  is formed from sheet metal which has been stamped and punched to create an upstanding bracket member that may be secured to the lamp housing  14 , for example, by fasteners  34 . 
   As best depicted in  FIG. 4 , the retainer bracket  30  includes a back wall  36  that forms a reference surface for accurately locating the lamp  12  within the lamp housing  14 . In the exemplary embodiment shown, the reference surface is defined by an arcuately shaped aperture  38  formed in the back wall  36 . The aperture  38  is configured to provide positive registration for the ceramic end caps  26  of the lamp  12 , whereby the lamp  12  may be placed in engagement with the retainer bracket  30  to ensure accurate and repeatable positioning of the lamp  12  relative to the housing  14 . First and second leg members  40   a ,  40   b  are disposed on opposing sides of the back wall  36 . First and second foot members  42   a ,  42   b  extend from distal ends of the first and second leg members  40   a ,  40   b  and are configured to engage the laterally extending supports  20  of the housing  14  while the first and second leg members  40   a ,  40   b  register against the vertical housing wall  18 . The retainer bracket  30  may thus be secured to the housing  14  by fasteners  34  installed through apertures  44 ,  46  formed in the leg members  40   a ,  40   b  and foot members  42   a ,  42   b  when placed in alignment with corresponding apertures formed in the housing  14  and arranged to position the reference surface aperture  38  of the bracket  30  at the desired location for receiving the UV lamp  12 . 
   As best illustrated in  FIG. 5 , the retainer clip  32  is formed from an elongate strip of flexible material, such as spring steel, to define a base portion  50  for engaging the retainer bracket  30 , and first and second confronting clip fingers  52   a ,  52   b  configured to engage the ceramic end caps  26   a ,  26   b  of the lamp  12  therebetween. The distal ends  53   a ,  53   b  of the clip fingers  52   a ,  52   b  are angled outwardly to facilitate installation of the lamp end caps  26   a ,  26   b  within the clip  32 . The clip  32  is coupled to the retainer bracket  30 , such as by fastening the clip  32  to a support tab  54  formed in the retainer bracket  30  and extending from an upper end of the back wall  36 . In the exemplary embodiment shown, clip  32  is fastened to support tab  54  by a fastener  56  installed through apertures  58 ,  60  formed in the clip  32  and support tab  54 , respectively. 
   Advantageously, the clip  32  is coupled to the bracket  30  adjacent the aperture formed in the back wall  36  such that when the ceramic end caps  26   a ,  26   b  of a UV lamp  12  are snapped into the clip  32 , the clip fingers  52   a ,  52   b  bias the surface  62  of the end caps  26   a ,  26   b  into registration against the aperture  38  to accurately position the lamp  12  relative to the housing  14  and reflector  22 , as shown in  FIGS. 1 and 2 . In the exemplary embodiment shown, the clip  32  is configured such that when the end caps  26   a ,  26   b  are snapped into the clip  32 , the base portion  50  of the clip  32  is spaced from the end caps  26   a ,  26   b  and only the distal ends  53   a ,  53   b  of the clip fingers  52   a ,  52   b  engage the end caps  26   a ,  26   b  so that accurate positioning of the lamp  12  is controlled by the aperture  38 . 
   The lamp retainer  16  of the present invention thus facilitates efficient installation and removal of a UV lamp  12  from a lamp assembly  10  while ensuring accurate and repeatable location of the lamp  12  with respect to the lamp housing  14 , reflector  22 . Advantageously, the positive registration feature of the lamp retainer  16  provides robust location performance that accommodates manufacturing variations in the retainer clip  32  or distortion that may occur in service. This robust performance also permits manufacturing tolerances to be loosened, thereby lowering manufacturing costs for the clip  32 . 
   While the present invention has been illustrated by the description of an embodiment thereof, and while the embodiment has been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.