Abstract:
The invention relates to a reflector lamp which comprises a reflector body ( 13 ) with a concave reflective part; an electric lamp ( 15 ) comprising a gastight lamp vessel with at least one end portion ( 18 ), an electric element ( 17 ) arranged in the lamp vessel, and a current conductor ( 19 ) extending through the end portion to the electric element; a support body ( 23 ) comprising reflector fastening means ( 30, 27 ) for fastening the support body to the reflector body, mechanical lamp vessel fastening means ( 43, 46 ) for fastening the support body to the end portion of the lamp vessel, and housing fastening means for fastening the support body inside the housing ( 2 ).

Description:
FIELD OF THE INVENTION 
     The invention relates to a reflector lamp which comprises a reflector body with a concave reflecting portion and an electric lamp, comprising a closed lamp vessel with at least an end portion, an electric element arranged in the lamp vessel, and current conductors extending through the end portion to the electric element. The invention also relates to an assembly of a lamp housing, a reflector lamp provided therein, and control means for controlling the reflector lamp, and to a method of assembling the above. 
     BACKGROUND OF THE INVENTION 
     Reflector lamps are known in which the lamp vessel after alignment is fastened in that it is fixed in a neck formed at the concave reflector body by means of an adhesive agent (cement). This is disadvantageous because curing of the adhesive agent keeps the apparatus in which the lamp is aligned occupied during a considerably longer period than is necessary for the actual alignment. A further disadvantage is that the quality of the cement joint may deteriorate strongly owing to moisture absorption, which hampers the use of the reflector lamp in humid surroundings. 
     In addition, reflector lamps are known in which the lamp vessel is fastened to said neck of the reflector body by means of a mechanical fastening construction. Such a fastening construction is described, for example, in applicant&#39;s European patent application EU 1 055 873 A2 not previously published. 
     A disadvantage of the known reflector lamps is that the alignment of the lamp is effected before the lamp is placed in the lamp housing by means of a separate fastening. This may mean that the lamp turns out to be insufficiently aligned after being placed. In addition, such a construction is comparatively complicated. 
     It is an object of the present invention to provide an improved reflector lamp in which the above disadvantages have been counteracted. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the invention, the reflector lamp for this purpose comprises a support body comprising reflector fastening means for fastening the support body to the reflector body, mechanical lamp vessel fastening means for fastening the support body to the end portion of the lamp vessel, and housing fastening means for fastening the support body in a lamp housing. A combined lamp and reflector fastening is achieved thereby, with the result that the lamp remains sufficiently aligned when placed in a housing. In addition, the number of components of the construction is reduced, which leads to a simpler construction. 
     In a preferred embodiment of the invention, the support body is provided substantially around the reflector body, and the reflector fastening means comprise one or several abutment flanges on which the end face of the reflector body bears in axial direction, and resilient tags fastened to the support body, which tags engage the reflector body and urge the reflector body against the abutment flanges. Besides the advantage of a simple mounting of the reflector body in the support body, the positioning of the reflector body is retained in this embodiment. 
     Preferably, the reflector fastening means comprise three resilient tags positioned at substantially equal distances, whereby centering of the reflector body in the support body is promoted. To achieve a further improved centering of the reflector body, the reflector fastening means in addition comprise one or several tangential resilient portions for clamping the support body against the reflector body. 
     In a preferred embodiment, the housing fastening means comprise a number of resilient tags for clamping the support body (with the reflector body and lamp vessel fastened therein) in a lamp housing. The tags may be rigidly coupled to the lamp housing by means of welded and/or glued joints. In other preferred embodiments, the support body may be fastened to the lamp housing with clamping fit, or directly by means of a glued or welded joint. 
     According to another aspect of the invention, a reflector lamp is provided, preferably of the kind as described above, comprising: 
     a reflector body with a concave reflecting portion; 
     an electric lamp comprising a closed lamp vessel with a first and an opposed second end portion, an electric element arranged in the lamp vessel, and current conductors extending through the end portion to the electric element; 
     wherein an opening is provided in the concave portion of the reflector body so as to serve as a passage for the first end portion of the lamp vessel, and said end portion is fixed by means of a mechanical fastening construction positioned in the reflector body alongside the opening. The mechanical fastening construction here engages the first end portion of the lamp vessel in or immediately above the opening. The use of such a reflector body without a neck enables a stabler fastening of the lamp (burner), because the latter is fastened closer to the focal point. On the other hand, the reflector body shows fewer deformations owing to accumulations of material at the area of said opening, which improves the quality of directing of the light beam and makes the product simpler and accordingly less expensive. In addition, less material is used in the manufacture, and the fastening process is simpler. 
     Preferably, the mechanical fastening construction comprises means for aligning the lamp vessel and keeping it fixed in the aligned state. This provides an alignment of the lamp vessel. 
     The electric element of the lamp may be an incandescent body, possibly placed in an inert gas, or a pair of electrodes in an ionizable medium, for example in rare gas, or rare gas and mercury and/or sodium, in which case a high-pressure discharge is maintained during operation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Further advantages, characteristics, and details of the invention will be explained in more detail in the ensuing description of a preferred embodiment. The description is given with reference to the Figures, in which: 
     FIG. 1 is a diagrammatic view of a reflector lamp and the control arrangements belonging thereto, both provided in a lamp housing; 
     FIG. 2 is a lateral perspective view of the preferred embodiment of the invention; 
     FIG. 3 is a perspective bottom view of the preferred embodiment of FIG. 2; and 
     FIG. 4 is a cross-sectional view of the preferred embodiment of FIGS.  2  and  3 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a light generator for introducing a light beam into a glass fiber cable f, for example for use in the automobile industry. In an alternative embodiment, for example, reflector lamps may be used in a projection television (beamer). 
     In the embodiment shown, the glass fiber cable f is connected to a lamp housing  2  via a coupling piece  1 . A concave reflector body  3  is provided in the lamp housing  2 , which body is provided on its inner surface with a reflecting coating, for example of metal such as aluminum or silver. An electric lamp  4  is connected to electric current conductors  5  and  6  and is fixed in the lamp housing  2  by means of a fastening  7 . The lamp  4  can be controlled in a known manner by a starter  9 , an error detector  10 , and further control electronics or ballast  8 . The assembly is connected to an electrical supply source (not shown) by means of a cord  11 . 
     FIGS. 2,  3 , and  4  show a preferred embodiment of a reflector lamp  12 . The lamp comprises a concave reflector body  13 , an opening  14  being provided in the top of this body. An electric lamp  15  with a lamp vessel closed in a vacuumtight manner is provided in the reflector body  13 . A first end portion  18  of the lamp vessel extends through the opening  14 , while the opposed second end portion  16  lies substantially on the axis of symmetry or optical axis of the reflector body  13 . The electric element  17  is present in the lamp vessel, and current conductors  19  and  20  extend through the first end portion  18  and the second end portion  16 , respectively, to the electric element  17 . The current conductors  19  and  20  are provided with protective sleeves  21  and  22  in the locations where they pass through the opening  14  in the reflector body  13 . 
     A support body  23 , preferably made of metal, is provided for a combined fastening of the lamp vessel to the reflector and of the reflector to a lamp housing, if present. The support body comprises an upper wall  24  to which a suspended wall  25  is fastened. A number of tags  26  is provided at the lower side of the suspended wall  25 , which tags are bent at their lower ends so as to form abutment flanges  27  on which the end face  28  of the reflector body  13  can bear in the mounted state. 
     The suspended wall  25  has been cut open in eight locations so as to obtain four resilient tags  30  for fastening the support body  23  to the reflector body  13 , and four resilient tags for fastening the support body  23  to the lamp housing (not shown). 
     The cross-sectional view in FIG. 4 shows how a resilient tag  30  is built up from a portion  31  which extends radially outwards and which merges into a tag  34  via a curved portion  32  and a portion  33  extending radially inwards. This construction is such that each of the tags  34  force the reflector body  13  provided in the support body in downward direction, (the direction indicated by an arrow) against the abutment flanges  27 . The reflector body  13  remains fixed to the support body  23  as a result of this. 
     Preferably, a metal strip  40  is provided around the tags  26 , which strip is given resilient portions  41  in a number of locations. The spring force of the resilient portions  41  ensures that the tags  26  are urged inwards such that the abutment flanges  27  remain correctly positioned below the end face  28  of the reflector body  13 . This is of importance especially in view of the difference in coefficient of thermal expansion between the metal support body  23  and the cover glass  29  with which the reflector body  13  is closed off. Differences in expansion between the glass and the metal parts arranged around it are compensated in that the strip  40 , and accordingly the tags  26 , are given a certain bias tension. 
     In addition, the above construction of tags  26  and  30 , whether or not in combination with said metal strip  40 , ensures that the reflector body  13  remains correctly centered with respect to the support body  23 . 
     To fasten the support body  23  to the lamp housing, a number of resilient tags  42  is provided at the support body  23 . These tags are S-shaped in the embodiment shown. The tags may have an alternative shape or construction, in dependence on the lamp housing used. 
     The support body  23  with the other parts of the reflector lamp fastened thereto can be fixedly clamped in the lamp housing by means of the resilient tags  42 . In some applications, the tags  42  are subsequently fixed to the lamp housing by means of welded joints and/or glue connections. 
     There are several possibilities for mechanically fastening the end portion  18  to the upper wall  24  of the support body  23 . In the embodiment shown, a plate  45  is fixed on the upper wall  24 , in which plate  45  two openings are provided for the end portion  18  and for the current conductor  22 , respectively. Four resilient tongues  46  bent in upward direction are cut from the plate  45 . In an alternative embodiment which is not shown, the plate  45  is omitted, and the resilient tongues are formed directly from the upper wall  24  of the support body  23 . A clamp  43  is fastened to the end portion  18 . The clamp  43  is provided with radially extending projections  44  in three positions which correspond to those of the tongues  46 . The projections  44  are each provided with a recess in which the upper side of the associated tongue  46  can be enclosed. The desired position of the lamp vessel in the Z-direction can be laid down by clamping the clamp  43  to the end portion  18  in a correct position In addition, the position of the lamp vessel in the XY-directions can be defined through bending of the tongues  46 . The lamp can be aligned in a simple manner by means of the mechanical construction described. 
     It is also conceivable to align the lamp first, and then to weld the plate  45  to the upper wall  24  of the support body  23  in a suitable position and fasten the lamp to the plate  45 . 
     Alternative constructions are possible in addition to the constructions described above. Thus the lamp vessel may be fastened to the reflector body  13  or to the support body  23  by means of a spring cup. This embodiment has the advantage that fewer components are required. 
     The usual neck of the reflector body has been omitted in all mechanical fastening constructions according to the invention. The absence of the neck renders it possible to fasten the lamp at a smaller distance from the focal point, which makes the fastening more stable.