Abstract:
A headband apparatus for head-worn optical instruments includes a headband ( 12 ) and a bow ( 16 ) on which the optical instrument is fitted, and which is fitted with both its ends ( 100 ) to the middle region of the headband ( 12 ) such that it can swivel about a swivel axis (S) between a working position and a rest position. Fastening elements ( 26, 28 ) for releasably fastening additional elements ( 38 ) are fitted on the headband ( 12 ).

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The invention relates to a headband apparatus for an optical instrument comprising a headband and a bow on which said optical instrument is mounted, said bow being mounted with both ends thereof at a middle region of said headband for swiveling about a swivel axis between a working position and a rest position.  
         [0003]     2. Description of the Background Art  
         [0004]     Such a headband apparatus known from U.S. Pat. No. 4,681,413 comprises an elastic headband surrounding the forehead and back of the head, and a crown band permanently connected thereto. The headband and the crown band can be adapted to the size and shape of the wearer&#39;s head with the aid of adjusting apparatuses. A bow is swivelably supported with its two ends in the middle side region of the headband. A binocular ophthalmoscope is fastened on the front side of the bow. The bow can be swiveled upward from a substantially horizontal working position, in which the ophthalmoscope is located in front of an examiner&#39;s eye into a rest position in which the ophthalmoscope is brought completely out of the examiner&#39;s field of view. Provided at one of the two swivel axes for the purpose of swiveling the bow is a latching device with two stops into which the bow latches in the working position or the rest position. The latching device has an operating element after the activation of which the bow can be unlocked and moved into the appropriate position. The latching device is permanently mounted on the swivel axis of the bow. This means that each examiner, whether a left- or right-hander must use the latching device, arranged on the side of the headband, in order to set the bow. If the latching device is arranged for right-handers, as is normally the case, this constitutes a substantial impairment of the operating comfort for a left-hander. For this reason, the manufacturer finds it necessary to make separate headband apparatuses available both for left-handers and right-handers, thus giving rise to substantial outlay on development and production. Moreover, the known headband apparatus does not provide any additional devices for fastening supplementary apparatuses or units. Finally, the bow is held in the working position at only one end by the latching device. Consequently, the bow is inclined downward in the direction of the other end because of the weight of the ophthalmoscope.  
       SUMMARY OF THE INVENTION  
       [0005]     The invention is therefore based on the object of providing a headband apparatus capable of universal use with the aid of simple means in terms of construction.  
         [0006]     This object is achieved according to the invention by a headband apparatus for a head-worn optical instrument, comprising a headband and a bow on which said optical instrument is mounted, said bow being mounted with both ends thereof at a middle region of said headband for swiveling about a swivel axis between a working position and a rest position, wherein fastening elements for releasably fastening at least one additional element are provided on said headband.  
         [0007]     According to the invention, fastening elements for releasably fastening additional elements are mounted on the headband. The field of use can be substantially expanded thereby.  
         [0008]     If the fastening elements form the swivel axes of the bow and extend outward through the ends of the bow, it is possible, for example, for a latching device to be mounted on one of the fastening elements in a rotationally fixed fashion by form-fitting engagement.  
         [0009]     The latching device can include a latching disk which is connected to the fastening element in a rotationally fixed fashion and has a circularly arcuate guide slot in which there is guided a latching pin which is connected to the bow in a rotationally fixed fashion and engages in a latching fashion in the guide slot in the working position and/or the rest position of the bow.  
         [0010]     A further additional element, for example a controller for controlling the brightness of a light source, drive electronics for a light source, a camera etc. can be mounted on another fastening element.  
         [0011]     Since the latching device is releasably fastened, it can be mounted on both sides of the head. This enables the latching device to be mounted on a side preferred for left handers or right handers.  
         [0012]     In a preferred embodiment, the fastening elements are respectively fastened at a free end of a connecting lug whose other end is permanently connected to the headband. The bow is thereby decoupled from the headband.  
         [0013]     The fastening element preferably passes through the latching disk and has a circumferential groove in which there engages in a locking position a locking element which is arranged in the latching disk and can be displaced transverse to the swivel axis into a release position in which it is disengaged from the circumferential groove. The locking element is expediently prestressed in the direction of the locking position. When the locking element is displaced into the release position, the complete latching device can be withdrawn from the fastening element and, if necessary, pushed on to the other fastening element and locked with the latter. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     An exemplary embodiment of the invention is explained in more detail below with the aid of drawings, in which:  
         [0015]      FIG. 1  shows a perspective illustration of a headband apparatus,  
         [0016]      FIG. 2  shows an oblique bottom view of the headband apparatus of  FIG. 1 ,  
         [0017]      FIG. 3  shows a perspective partial view of the headband apparatus of  FIG. 1  in the region of the articulation of a bow with a partially mounted latching device,  
         [0018]      FIG. 4  shows the view of  FIG. 3 , a swivel plate additionally being mounted,  
         [0019]      FIG. 5  shows a section through the bearing of the bow and the latching device,  
         [0020]      FIG. 6  shows an exploded illustration of the latching device,  
         [0021]      FIG. 7  shows perspectively a partial excerpt of the headband apparatus of  FIG. 1  in the region of the bearing of a bow,  
         [0022]      FIG. 8  shows an exploded illustration of the partial excerpt of  FIG. 7 , seen from outside,  
         [0023]      FIG. 9  shows an exploded illustration of the partial excerpt of  FIG. 7 , seen from inside.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     The headband apparatus  10  shown in  FIGS. 1 and 2  comprises a headband  12  that can be adjusted by an adjusting device  24  and of which a crown band  14 , which can be adjusted by an adjusting device  22 , extends upward. In the front region, surrounding the user&#39;s forehead, of the headband  12 , connecting lugs  18 ,  20  are fastened on both sides at one end and extend to the respective middle region of the side. At the free end of the connecting lugs  18 ,  20 , one end of a bow  16  is swivelably supported in each case by fastening elements  26 ,  28 . In the position shown in  FIGS. 1 and 2 , the bow  16  is located in a substantially horizontal position in which it surrounds the front region of the headband  12 . A fastening device  30  for fastening an ophthalmoscope is provided at the middle region of the bow  16 .  
         [0025]     The bow  16  is formed by a molded plastic part, the electric supply cables being integrated in the bow.  
         [0026]      FIGS. 3 and 4  show perspective illustrations of the headband apparatus  10  in the region of the bearing of the bow  16  by the fastening element  26 .  FIG. 5  shows a sectional illustration of the bearing with a latching device  38 , while  FIG. 6  shows an exploded illustration in this region.  
         [0027]     The free end of the connecting lug  20  has a thickened end  104  with a passage opening  105 . The fastening element  26  with a threaded shoulder  50  passes through this passage opening  105  in the direction of the headband  12 . On the side of the thickened section  104  averted from the headband  12 , a cylindrical bearing section  52  bears against the fastening element  26 . Adjoining the bearing section  52  in the direction of the headband  12  is a square profile  115  ( FIG. 9 ) that is arranged in a square opening  111  ( FIG. 9 ) of the thickened section  104  in order to fit the fastening element  26  on the fastening lug  20  in a rotationally fixed fashion. The fastening element  26  is permanently connected to the connecting lug  20  by a nut (not shown) mounted on the threaded shoulder  50  adjoining the square profile  115 . At its thickened end  100 , the bow  16  has a continuous bearing opening  94  that surrounds the bearing section  52  of the fastening element  26 , such that the bow  16  is supported at the bearing section  52  such that it can rotate about a horizontal swivel axis S. Bearing against the side, averted from the headband  12 , of the thickened end  100  of the bow  16  is a latching disk  32  that has an extension  36  extending forward in a substantially horizontal fashion. A circularly arcuate guide slot  34  is formed in the extension  36 , the center of the circular arc lying on the swivel axis S of the bow  16 , which coincides with the central axis of the fastening element  26  and the through openings  94  and  105 . The fastening element  26  passes through a polygonal opening  107  (for example square opening) in the latching disk  32 , the profile of which corresponds to the outer profile of a polygonal section  54  of the fastening element  26 , as a result of which a rotationally fixed connection is produced between the latching disk  32  and the fastening element  26 . Adjoining the polygonal opening  107  is a cylindrical section  66  of the latching disk  32  that is flush with the fastening element  26 . The cylindrical section  66  is surrounded at a distance in the front region by a wall  60  formed in the latching disk  32 . Provided in the cylindrical section  66  in a fashion facing the wall  60  is a cutout  64  that is at the level of a circumferential groove  56  that is formed in the fastening element  26 . A swivel plate  42  with its through opening  82  is pushed on to the cylindrical section  66  in a fashion adjoining the wall  60  and the cutout  64 .  
         [0028]     Inserted between the swivel plate  42  and the latching disk  32  is a blocking slide  40  that has a through opening  74  through which the cylindrical section  66  passes. The blocking slide  40  surrounds the cylindrical section  66  at the level of the cutout  66  and the wall  60 . Adjoining the cutout  64  in the cylindrical section  66 , the through opening  74  has a straight circumferential edge  72  that engages in the cutout  64  and in the circumferential groove  56  in the fastening element  26  when the blocking slide  40  is moved rearward transversely to the swivel axis S, that is to say away from the wall  60 . The latching disk  32  is thereby locked on the fastening element  26 . The blocking slide  40  is prestressed into the locking position by a spring (not shown) arranged between the wall  60  and the blocking slide  40 . When, by exerting pressure on a pressure part  76 , arranged displaceably in an incision  68  in the latching disk  32 , of the blocking slide  40 , the blocking slide  32  is moved forward against the pressure force of the spring, the edge  72  is moved out of the circumferential groove  56  in the fastening element  26 , as a result of which the latching disk  32  is unlocked from the fastening element  26 , and the entire latching device  38  can be withdrawn.  
         [0029]     The swivel plate  42  extends forward perpendicular to the swivel axis S of the bow  16 . Provided in the front region is a journal opening  80  that is flush with an insertion opening  95  in the thickened end  100  of the bow and is at the level of the guide slot  34 . A bush sleeve  84  is guided with a threaded neck  86  through the journal opening  80  and fastened on the swivel plate  42  by means of a nut  78 . The bush sleeve  84  bears against the swivel plate  42  with a collar  88  from which a cylindrical section  89  extends outward. Plugged from outside into the bush sleeve  84  is a bearing bush  90  into which there is inserted a cylindrical section  99  of a latching pin  96  that passes through the guide slot  34  and has a plug-in section  97  that is displaceably inserted into the plug-in opening  95 . Formed on the latching pin  96  between the latching disk  32  and the thickened section  100  of the bow  16  is a conical collar  98  whose shape is conformal with the shape of latching depressions  35 ,  37  in the guide slot  34  that correspond to a rest position or working position of the bow  16  and are formed at the upper end or lower end of the guide slot  34 . A pressure head  92  is displaceably mounted on the outer end of the bush sleeve  84 , a helical pressure spring  91  being provided between the collar  88  of the bush sleeve  84  and the pressure head  92 . The pressure head  92  is screwed with the aid of a thread  87  of the latching pin  96 . A cap  93  that covers the entire latching device  38  from outside is mounted on the pressure head  92  from outside.  
         [0030]     When a pressure is exerted on the cap  93  in the direction of the bow  16 , the latching pin  96  is moved via the pressure head  92  against the pressure force of the pressure spring  91  in the direction of the bow  16  until the conical collar  98  bears against the thickened end  100  of the bow  16 . In this position, the conical section  98  is located outside the corresponding depression  35  or  37  in the guide slot  34  in the latching disk  32 , thereby rendering it possible for the latching pin  96  to move inside the guide slot  34  as the swivel plate  42  swivels in a circular track about the swivel axis S, the bow  16  being carried along by the plug-in section  97 , plugged into the plug-in opening  95 , of the latching pin  96 , and is swiveled about the swivel axis S. As soon as the conical section  28  reaches the other depression  35  or  37 , the conical section  98  snaps into the corresponding depression  35  or  37  by the action of the pressure spring  91 , the bow  16  thereby being locked.  
         [0031]     The entire latching device  38  including the latching disk  32 , blocking slide  40 , swivel plate  42 , latching pin  96 , cap  93  etc. can be withdrawn from the fastening element  26  when a pressure force is exerted on the blocking slide  40  in the direction of the swivel axis S, and the edge  72  is moved therethrough out of the circumferential groove  56  in the fastening element  26 . The latching device  38  is then withdrawn from the fastening element  26  and can be plugged in the same way on to the identically designed fastening element  28  on the opposite side of the headband  12 , the other end of the bow  16  being designed in the same way as the end described.  
         [0032]      FIGS. 7, 8  and  9  show an enlarged perspective partial excerpt of the headband apparatus  10  in the region of the articulation of an end of the bow  16 . At its thickened end  104 , the connecting lug  20  has a rearwardly extending semicircular elevation  101  that concentrically surrounds the square opening  111  and projects outward from a bearing surface  103  of the thickened end  104 . The elevation  101  finishes above in a stop surface  107 , and below in a stop surface  101 , both of which point forward and lie in a substantially vertical plane that intersects the swivel axis S.  
         [0033]     Provided at the thickened end  100  of the bow  16  is an oppositely arranged step  109  that merges at the bottom, via a rearwardly pointing stop surface  102 , into a bearing surface  119  that bears against the top side of the elevation  101 . The stop surface  102  extends radially downward from the edge of the bearing opening  94  and bears against the stop surface  106  of the connecting lug  20  when the bow  16  is in the substantially horizontal working position. Formed in the upper region is a substantially vertically arranged step surface  117  that runs perpendicular to the bearing surface  119  and is arranged at a distance in front of the bearing opening  94 . Adjoining the step surface  117  is a bearing surface  113  that runs obliquely downward in the direction of the midpoint of the bearing opening  94  and finishes at the edge of the bearing opening  94 . The stop surface  113  is arranged such that it bears against the bearing surface  107  of the connecting lug  20  when the bow  16  is swiveled upward into the rest position.  
         [0034]     Corresponding stop surfaces  102 ,  113 ,  106 ,  107  are provided at both ends of the headband  12  on the bow  16  and/or the connecting lug  20 .  
         [0035]     The fact that the stop surfaces  102 ,  106  bear at both ends in the horizontal position of the bow  16  prevents the bow  16  from being inclined at one end through the weight of the ophthalmoscope fastened on the fastening device  30  when it is locked in the horizontal position at the other end by the latching device  32 .