BACKGROUND OF THE INVENTION 
   1. Technical Field 
   The invention relates to a position lamp for watercraft or for placing ashore, in particular a multicolored lamp, having light to be emitted in at least two different directions and at least one light source per direction, the light passing optically refractive elements. Position lamps are also called navigation lamps in Germany. 
   2. Prior Art 
   It is known to use 2-color lamps or 3-color lamps, at least for smaller watercraft, green light being emitted front right in the direction of travel, red light being emitted front left in the direction of travel, and white light being emitted rearwards (3-color lamp). The light sources and optically refractive elements must be arranged and aligned precisely relative to one another, in order to be able to illuminate accurately the angular ranges prescribed by statute. The present invention aims to facilitate and/or improve the said arrangement of the light sources and optically refractive elements. 
   BRIEF SUMMARY OF THE INVENTION 
   The position lamp according to the invention is characterized in that a dedicated optically refractive element is provided per light source, and in that the optically refractive elements are held on a common housing body, the housing body also accommodating the light sources. The housing body therefore serves as a base for the light sources and the optically refractive elements and is of solid or at least semisolid design with stable walls on which the light sources or optically refractive elements can be arranged and/or fastened with high accuracy. Consequently, the precise production of the housing body already suffices to ensure it is possible to produce a position lamp which meets the statutory regulations extremely accurately. The relative arrangements of the light sources and optically refractive elements with regard to one another are fixed by the shape and/or design of the housing body. The housing body is preferably produced from aluminium or another thermally conductive metal and/or an alloy, since the waste heat of the light sources is also intended to be dissipated via the housing body. Provided, in particular, as light sources are LEDs, preferably one LED per color and/or precisely one LED for each optically refractive element. 
   According to a further idea of the invention, the housing body has a dedicated support surface for each optically refractive element. The angles between the support surfaces then essentially also define the angles between the individual light sources. 
   According to a further idea of the invention, the support surfaces each have approximately in the middle an opening and/or recess or depression, particularly for the passage and/or for the insertion of a printed circuit board with LED (or another luminous means), for leads or other components. 
   According to a further idea of the invention, the optically refractive elements have projections which enter the openings and/or recesses and thus ensure the arrangement of the optically refractive elements in defined positions relative to the housing body. The openings are preferably provided with edges against which corresponding edges or surfaces of the projections bear such that the optically refractive elements cannot move laterally, that is to say parallel to the support surfaces. 
   According to a further idea of the invention, the position lamp is characterized by screens for covering side areas of the optically refractive elements. The light exit areas are set accurately in accordance with the statutory regulations via the size and shape of the screens. Different screens can be used depending on regulation and country. 
   According to a further idea of the invention, it is provided that at least one of the screens is arranged between two optically refractive elements and covers neighbouring side areas of these two optically refractive elements. 
   Lenses are preferably provided as optically refractive elements. In the case of 2-color or 3-color lamps, at least two lenses can be of identical design in each case. Again, the lenses turn out to be correspondingly smaller than is the case with a single optically refractive element for the entire position lamp. The lenses are preferably designed on one side for bearing against the support surfaces. 
   According to a further idea of the invention, between the support surfaces the housing body has recesses for accommodating projections provided on the screens. The screens are held, at least accurately positioned, in the recesses between the support surfaces with the aid of the projections. 
   According to a further idea of the invention, it is provided that the recesses between the support surfaces are slots, and in that the projections are, in particular, extensions. The extensions enter the slots. It is therefore impossible for the screens to twist. There are respectively narrow areas which extend in a vertical direction in the case of customary 3-color lamps between the bearing surfaces. The slots also correspondingly run in a vertical direction and, at the same time, into the housing body, approximately in the direction of an imaginary middle of the housing body. 
   According to a further idea of the invention, at least one of the screens has a T-shaped cross section with three extensions, specifically one plug-in extension and two covering extensions. The plug-in extension can be plugged in to the associated slot in the housing body, while the covering extensions cover side areas of the optically refractive elements to the extent this is required. 
   According to a further idea of the invention, a heat sink is provided below or above the housing body and bearing against the latter. The heat sink is preferably of disc-shaped design and serves for dissipating and/or distributing the lost heat of the light sources and absorbed by the housing body. 
   According to a further idea of the invention, the heat sink has recesses or slots for the entry of parts of screens. The recesses or slots in the heat sink correspond to the recesses or slots in the housing body, but are arranged at right angles thereto. In the case of screens of T-shaped configuration, the plug-in extensions and covering extensions are thus also guided laterally. 
   The position lamp according to the invention can be coupled to a further position lamp, for example to a top light or an anchor light. Here, this additional position lamp has a light exit, substantially across a plane, which is circumferential or at least covers a wide angle, and having an LED as light source and an optically refractive element for deflecting and distributing the light, the LED being arranged with a principal radiation direction perpendicular to the light exit plane. Such a lamp is known, for example, from the Applicant&#39;s DE 198 34 520. The optically refractive element is of annular design there. The aim of the present invention is to provide an alternative embodiment. 
   It is provided according to the invention that the optically refractive element is of solid cylindrical design with a light entry surface at one end, a circumferential light exit surface, and with a reflective surface opposite the light entry surface, the reflective surface being formed by a funnel-shaped/V-shaped depression at an end opposite the light entry surface. 
   It goes without saying that the position lamp defined above can also be used independently of the invention outlined at the beginning or earlier, and also constitutes an independent invention. 
   The light entry surface is advantageously of convex design. Owing to the convex configuration of the light entry surface, the light emitted by the LED is introduced into the optically refractive element in a targeted fashion and at defined angles. 
   According to a further idea of the invention, the light entry surface is at the same time the bottom of a cylindrical depression in the optically refractive element, the LED dipping at least partially into the depression. Consequently, the optically refractive element has the reflective surface at one end, and the cylindrical depression with the light entry surface as bottom at the other end. 
   According to a further idea of the invention, the optically refractive element is covered by an opaque lid at the end opposite the light entry surface, in particular a circumferential covering wall bearing against a circumferential edge of the funnel-shaped/V-shaped depression. The intention is that as far as possible no light is to exit from the funnel-shaped depression defining the reflective surface. Light which possibly exits is shaded by the abovementioned circumferential covering wall. Moreover, the circumferential covering wall can dissipate heat from the optically refractive element via the circumferential edge of the funnel-shaped depression, and fix the edge laterally. In a corresponding way, the lid is preferably produced from aluminium or another thermally conductive metal or an alloy. 


   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further features of the invention follow in addition from the description and from the claims. Advantageous exemplary embodiments of the invention are explained below in more detail with the aid of drawings, in which: 
       FIG. 1  shows a side view of a position lamp according to the invention, specifically a 3-color lamp. 
       FIG. 2  shows a longitudinal section of the 3-color lamp in accordance with  FIG. 1 . 
       FIG. 3  shows a top view of the 3-color lamp in accordance with  FIG. 1 . 
       FIG. 4  shows an exploded illustration of the individual components of the 3-color lamp in accordance with  FIG. 1 . 
       FIG. 5  shows an exploded illustration of further parts of the 3-color lamp in accordance with  FIG. 1 , specifically a housing body with screens and LEDs on printed circuit boards. 
       FIG. 6  shows a side view of a further position lamp according to the invention. 
       FIG. 7  shows a longitudinal section through the position lamp in accordance with  FIG. 6 . 
       FIG. 8  shows a top view of the position lamp in accordance with  FIG. 6 . 
       FIG. 9  shows a bottom view of the position lamp in accordance with  FIG. 6 . 
       FIG. 10  shows an exploded illustration of the position lamp in accordance with  FIG. 6 . 
       FIG. 11  shows a perspective illustration of the position lamp in accordance with  FIG. 6 , specifically obliquely from above. 
       FIG. 12  shows a side view of a combination of the two position lamps in accordance with  FIGS. 1 and 6 . 
       FIG. 13  shows a longitudinal section through the combined position lamp in accordance with  FIG. 12 . 
       FIG. 14  shows a side view offset by 90° from the illustration in  FIG. 12 . 
       FIG. 15  shows a top view of the combined position lamp in accordance with  FIG. 12 . 
       FIG. 16  shows an exploded illustration of the combined position lamp in accordance with  FIG. 12 . 
   


   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The construction of a novel position lamp, specifically a 3-color lamp for smaller watercraft, in particular, is firstly explained with the aid of  FIGS. 1 to 5 . The lamp  20  is of substantially cylindrical construction with a substantially disc-shaped upper part  21 , a substantially pot-shaped lower part  22 , a substantially pot-shaped base  23 , a substantially disc-shaped insert  24 , a substantially disc-shaped lid  25 , and a housing body  26  as middle part. The housing body  26  is surrounded by a sleeve-shaped transparent cover  27 . 
   The lower part  22  and base  23  are connected to one another by a bayonet ring  28  with an inserted seal  29 . At the top, the lid  25  is screwed onto the upper part  21  with an interposed sealing disc  30  (or sealing mat). 
   Again, the upper part  21  and the lower part  22  are screwed to one another. Provided for this purpose at a central point is an axially aligned, continuous screw  31 . The latter extends in this case through an axially directed bore  32  in the housing body  26 , and likewise through a bore  33  in the insert  24 . The transparent cover  27  between the lower part  22  and the upper part  21  is also held and fixed in depressions correspondingly running round at the edge by tightening the screw  31 . 
   The housing body  26  is of substantially solid or semi-solid design and consists of aluminium or another material which is a good conductor of heat. The components further mentioned can also be designed to conduct heat in a correspondingly effective fashion. 
   Provided as light sources are a white LED  34 , a red LED  35  and a green LED  36 . The LEDs  34 ,  35  and  36  are seated on associated printed circuit boards  37 ,  38 ,  39 . 
   The housing body  26  has a cross section which is substantially in the shape of an isosceles triangle. On the outside, the housing body  26  correspondingly has three support surfaces  40 ,  41 ,  42  angled away from one another. 
   The support surfaces  40 ,  41 ,  42  each have a recess  43 ,  44 ,  45  in which the associated printed circuit board  37 ,  38 ,  39  is respectively arranged. The printed circuit boards  37 ,  38 ,  39  are preferably encapsulated. 
   The recesses  43 ,  44 ,  45  have side edges matched to the outer shape of the printed circuit boards  37 ,  38 ,  39 , thus giving rise to a unique positioning of the printed circuit boards in the recesses. 
   The light emitted by the LEDs  34 ,  35 ,  36  is focused by means of one preposed lens  46 ,  47 ,  48  in each case. The lenses bear on the outside against the support surfaces  40 ,  41 ,  42 , have an outer shape that is substantially partially cylindrical, and are provided with projections  49 ,  50  which bear against corresponding side edges of the recesses  43 ,  44 ,  45 , and thus define the position of the respective lens uniquely. 
   In addition, each lens can have an extension  51  which respectively extends next to the associated recess  43 ,  44 ,  45  into the interior of the housing body  26  and guides a portion of the emitted light. A dedicated light sensor can be provided for each extension  51  in the interior of the housing body  26  and be used to detect the luminous intensity output with lapse of time. An electronic circuit (not shown) can then be used to readjust the electric power of the LEDs individually in order to achieve a constant luminous intensity. 
   The housing body  26  respectively has one axially directed slot  52 ,  53 ,  54  each between the individual support surfaces  40 ,  41 ,  42 . The slots are provided for accommodating screens  55 ,  56 ,  57 . 
   Each screen  55 ,  56 ,  57  has a substantially T-shaped cross section with a middle plug-in extension  58  and two lateral covering extensions  59 ,  60 . Each plug-in extension  58  is provided to be accommodated by the associated slot  52 ,  53 ,  54  and has corresponding dimensions. The covering extensions  59 ,  60  of the screen  56  cover side areas of the lenses  47 ,  48  for the port and starboard LEDs  35 ,  36 . The emission angle is thereby accurately delimited in the principal direction of travel of the ship. Similarly, the lateral covering extensions  59 ,  60  of the lateral screens  55 ,  57  act on the one hand as screens for the lenses  47 ,  48 , and on the other hand as screens for the lens  46  of the white LED  34 , which functions as a stern light. 
   The covering extensions  59 ,  60  merge into one another and are designed in a curved fashion which corresponds, or is similar, to the curvature of the transparent cover  27 . The latter allows the light of the LEDs to pass through and at the same time protects lenses, screens, LEDs and electronic components from external influences. 
   The housing body  26  is seated on the insert  24 . The latter has bores  61  for the passage of electric leads via which the LEDs are supplied with current. The electric leads are not shown, and run from the rear side of the printed circuit boards  37 ,  38 ,  39  through corresponding cavities in the housing body  26  and through the abovementioned bores  61  as far as a rear side (not visible in  FIG. 4 ) of the insert  24 . There, a printed circuit board  62  is encapsulated with corresponding electronic components for supplying the LEDs. 
   Further electronic components can also be arranged in the base  23 . The latter has a bore  63 , directed obliquely downwards, for the passage of an electric lead. 
   In order to fix a precise relative position of the insert  24  with reference to the housing body  26 , the insert  24  has slots  65 ,  66 ,  67  on its top side  64  which correspond to the extensions  58 ,  59 ,  60 . The latter can interact at the same time with projections  68 ,  69 , in the lower part  22 , and thus fix the position of the insert  24  in the lower part  22 . 
   Instead of the lid  25 , a further position lamp, for example a top light, anchor light or allround light, can be arranged on the upper part  21 . In the present case, a white signal lamp  70  (allround light) is provided. Its design is explained below with the aid of  FIGS. 6 to 11 . 
   The signal lamp  70  has a base  71 , a dome-like base housing  72 , a sleeve-shaped transparent cover  73  and a lid  74 . 
   A printed circuit board  75  with a white LED  76  is held on the base  71  in a fashion protected by the base housing  72  lying above it. A top side  77  of the base  71  is provided with a mount  78  whose inner edge has projections and recesses and corresponds to matching projections and recesses on the printed circuit board  75 , and thus ensures a unique position of the printed circuit board  75  on the base  71 . The contour of the mount  78  corresponds to the cutouts  43 ,  44 ,  45 . The outer shape of the printed circuit board  75  can therefore match the printed circuit boards  37 ,  38 ,  39 . 
   The base housing  72  is held on, or connected to, the base  71  by axially directed screws. The base housing  72  also has an axially directed, middle bore  79  for accommodating or for passage of a cylindrical lens  80 . The latter extends from the LED  76  up to the lid  74 , and is provided at an upper end with a funnel-shaped depression  81  which has a wall  82  running round on the inside. The said wall simultaneously forms a reflective surface of the lens  80 . 
   At an end of the lens  80  opposite the depression  81 , that is to say in the region of the LED  76 , the lens  80  has a cylindrical depression  83  which terminates with a convex light entry surface  84 . The LED  76  dips into the depression  83  and is at only a slight distance from the light entry surface  84 . 
   The depression  83  is delimited by a circumferential edge  85 . The latter bears against parts of the printed circuit board  75  and justifies the relative position of the LED  76  with reference to the lens  80 . In accordance with the predominantly solid, cylindrical shape of the lens  80 , the latter has a circumferential cylindrical wall  86  as light exit surface. In the area of the cylindrical depression  83 , the lens  80  has a conical outer shape such that the circumferential edge  85  has a distinctly smaller diameter than the circumferential wall  86 . 
   In the area of the transition between the circumferential wall  86  and the conical area adjoining below the latter, the lens  80  has a circumferential collar  87 . The latter bears internally against the base housing  72 , and so only approximately ⅔ of the axial length of the circumferential wall  86  projects beyond the base housing  72  in the direction of the lid  74 . 
   The light emitted by the LED  76  passes through the convex light entry surface  84  into the solid lens  80 , is reflected at the wall  82 , and exits via the circumferential wall  86 , specifically in a fashion substantially perpendicular to the principal direction of emission of the LED  76 . Subsequently, the light still transits merely the transparent cover  73  and, beforehand, the space between the latter and the lens  80 . 
   The lid  74  is provided with a circumferential extension  88  which is axially directed and bears against the circumferential wall  86 , specifically in the area of the transition to the funnel-shaped wall  82 . For this purpose, the circumferential extension  88  has a somewhat wider outside diameter than the circumferential wall  86 , and is provided with an inwardly directed step such that the circumferential wall  86  is secured in this area against transaxial movements. The contact also enables heat to be exported from the lens  80  into the lid  74 . 
   The lens  80  and/or transparent cover  73  are/is connected by bonding to the lid  74 , on the one hand, and to the base housing  72 , on the other hand. 
   A printed circuit board with the required electronic circuits is arranged on an underside of the base  71 . Power is supplied via leads  90  which are guided from the printed circuit board  89  in the direction of the 3-color lamp lying thereunder. The upper part  21 , housing body  26  and insert  24  have the additional lead bushings necessary therefor. 
   Since the signal lamp  70  is provided instead of the lid  25 , the base housing  72  has leadthroughs for screws in a fashion similar to the fastening of the lid  25 . 
   The sealing disc  30  in accordance with  FIG. 10  is also shown in  FIG. 4 , consists of rubber and has an insulating effect here (see  FIG. 7 , in particular) between the base  71  and the upper part  21  depicted in  FIG. 4 . 
     FIGS. 12 to 16  show a position lamp as a combination of the above-described 3-colour lamp  20  and the signal lamp  70 . Despite the highly integrated design, the combination is simple in structure and its electrical functioning. The option of producing the described combination of 3-colour lamp and signal lamp or only the 3-colour lamp can be exercised on the basis of the same design by a simple modification, specifically by exchanging the signal lamp  70  for the lid  25 . 
   It remains possible to access the electric terminals easily owing to the bayonet ring  28 , already mentioned above, which permits the upper part  21  and base  23  to be separated from one another. 
   LIST OF REFERENCE NUMERALS 
   
     
       
             
             
           
         
             
                 
             
           
           
             
               20 
               3-color lamp 
             
             
               21 
               Upper part 
             
             
               22 
               Lower part 
             
             
               23 
               Base 
             
             
               24 
               Insert 
             
             
               25 
               Lid 
             
             
               26 
               Housing body 
             
             
               27 
               Transparent cover 
             
             
               28 
               Bayonet ring 
             
             
               29 
               Seal 
             
             
               30 
               Sealing disc 
             
             
               31 
               Screw 
             
             
               32 
               Bore 
             
             
               33 
               Bore 
             
             
               34 
               White LED 
             
             
               35 
               Red LED 
             
             
               36 
               Green LED 
             
             
               37 
               Printed circuit board 
             
             
               38 
               Printed circuit board 
             
             
               39 
               Printed circuit board 
             
             
               40 
               Support surface 
             
             
               41 
               Support surface 
             
             
               42 
               Support surface 
             
             
               43 
               Recess 
             
             
               44 
               Recess 
             
             
               45 
               Recess 
             
             
               46 
               Lens 
             
             
               47 
               Lens 
             
             
               48 
               Lens 
             
             
               49 
               Projection 
             
             
               50 
               Projection 
             
             
               51 
               Extension 
             
             
               52 
               Slot 
             
             
               53 
               Slot 
             
             
               54 
               Slot 
             
             
               55 
               Screen 
             
             
               56 
               Screen 
             
             
               57 
               Screen 
             
             
               58 
               Plug-in extension 
             
             
               59 
               Covering extension 
             
             
               60 
               Covering extension 
             
             
               61 
               Bore 
             
             
               62 
               Printed circuit board 
             
             
               63 
               Bore 
             
             
               64 
               Top side 
             
             
               65 
               Slot 
             
             
               66 
               Slot 
             
             
               67 
               Slot 
             
             
               68 
               Projection 
             
             
               69 
               Projection 
             
             
               70 
               Signal lamp 
             
             
               71 
               Base 
             
             
               72 
               Base housing 
             
             
               73 
               Transparent cover 
             
             
               74 
               Lid 
             
             
               75 
               Printed circuit board 
             
             
               76 
               LED 
             
             
               77 
               Top side 
             
             
               78 
               Mount 
             
             
               79 
               Bore 
             
             
               80 
               Lens 
             
             
               81 
               Depression (V-shaped) 
             
             
               82 
               Wall 
             
             
               83 
               Depression (cylindrical) 
             
             
               84 
               Light entry surface 
             
             
               85 
               Circumferential edge 
             
             
               86 
               Circumferential wall 
             
             
               87 
               Bore 
             
             
               88 
               Extension 
             
             
               89 
               Printed circuit board 
             
             
               90 
               Leads
A position lamp for watercraft or for placing ashore, in particular a multicolored lamp, having light to be emitted in at least two different directions and at least one light source per direction, the light passing optically refractive elements, and in which a dedicated optically refractive element is provided per light source, the optically refractive elements being held on a common housing body, the housing body also accommodating the light sources.