Patent Publication Number: US-2007114252-A1

Title: Helmet holder for a vision device, in particular for a night vision device

Description:
The invention relates to a helmet holder for a vision device, in particular for a night vision device, according to the preamble of claim  1 .  
      Various vision devices, for example night vision or thermal imaging devices, are used for very specific applications by military, police and border protection forces in order to be able to carry out operation under poor visual or light conditions or in darkness. Night vision devices, for example, amplify the low light level and produce an image visible to the human eye.  
      Night vision devices, like binoculars, can be used independently and manually. They are used—like binoculars—as a binocular version having separate eyepieces for each eye or as a monocular version having only one eyepiece.  
      In most cases, for example in military or police use, it is necessary for the user to have his hands free and for the vision device, for example a night vision device, to be fixed on the wearer&#39;s head, for example to be fastened to a head covering, preferably a helmet.  
      Depending on light conditions, the night vision device is used in an operating position in front of the user&#39;s eye or in a rest position in which the night vision device is held outside the field of vision of the user. For adaptation to the different head shapes and eye positions of the user, it is necessary to have adjustment mechanisms which enable the user to carry out adaptation to his personal needs.  
      In many applications, the user needs to obtain a constantly steady image, even in the case of extreme physical movements, such as running or jumping, or in the case of vibrations during driving; the eyepiece of the vision device should be capable of executing only a minimum relative movement. In other applications, the user is dependent on the night vision device being held in a position very close to the head, both in the operating position and in the rest position, and not projecting substantially beyond the user&#39;s head either in the horizontal direction or in particular in a vertical direction.  
      Simple helmet fixing means are known, for example from U.S. Pat. No. 4,457,461, which however have no possibility of enabling the night vision device to be removed from the field of vision under adequate light conditions without having to remove it by an inconvenient procedure.  
      For eliminating this deficiency, systems having pivot mechanisms are being constructed. An exemplary embodiment of this type is disclosed in DE-69321234. In the system described there, the night vision device is fixed by means of a connecting piece to a slide which is fixed by means of a pivot fitting to the fitting fixed to the head covering by a strut, in a manner so as to be rotatable about a pivot axis. The fixing of the operating and rest position is effected by a spring-loaded catch apparatus.  
      What proves to be disadvantageous in such arrangements is that the strut having an axel shaft forms an axis of rotation above the front helmet edge, with the result that, in the rest position, the night vision device projects very considerably beyond the body height of the user. Because of this circumstance, there is a considerable danger of damage when passing through door frames or other obstacles limiting the height of passage, and furthermore use in low rooms, such as in vehicle cabins, is greatly restricted.  
      In order to obtain a mounting which permits good movement about the pivot axis, a certain play is required between the components, and this is equally necessary for protection from jamming between the components of spring-loaded catch apparatuses. In summary, this results, in the locked positions, chiefly in the operating position of the vision device, to a greater extent owing to the long lever arm of the eyepiece relatively far away from the pivot axis, in an instability in the region of a few tenths of a millimeter. During fast running or in the event of vibrations, there is a relative movement between the user&#39;s eye and the eyepiece owing to inertia, which leads to an unstable image.  
      A further disadvantage is that the locking springs exert the spring force only in the immediate region of the operating and rest position and there is no compensation of the weight of the night vision device. In the event of sudden release of the locking in the rest position due to external effects, such as impact or during jumping, the night vision device may fall through its own weight with possibly great speed from the rest position into the operating position, which can lead to irritation and shock for the user and, if the helmet fits loosely, even to eye injuries.  
      In order to overcome the disadvantage of the prior art, an object of the present invention is to provide a holder for a vision device so that the vision device, in particular night vision device, is held in such a way that—during any use—a steady image which is as free of vibration as possible is obtained. Furthermore, or alternatively, a compact arrangement of the vision device should be possible both in the rest position and in the operating position. Furthermore, or alternatively, the vision device should remain held as reliably as possible in the rest position—even under impact-like effects—so that unintended, sudden swivelling of the vision device into the operating position, which may startle the user, is avoidable. Furthermore, or alternatively, in particular abrupt movements of the vision device, at least those from the rest position to the operating position should be damped.  
      This object is achieved by a holder for a vision device, in which the defining features of the independent claims are realized. Alternative or advantageous developments are described by the defining clauses of the dependent claims.  
      According to the invention, freedom from play of the holder—vision device system is ensured by the installation, the arrangement and the design of a spring-mechanism. The possible plays are pretensioned by spring force so that no plays become effective until this force has been overcome, since the interlocking of all parts due to the gaps between the individual components being closed under pressure of the spring force is completely retained.  
      If a damping element is co-ordinated with the rotating element which is arranged on the arm and is non-rotatably connected to the receptacle for the vision device, on movement of the vision device—at least on movement from the rest position to the operating position—its speed of movement is reduced at least over a partial range of the movement. Thus, shock or irritation or even possibly injuries to the user owing to uncontrolled hasty handling of the vision device or owing to unintentional swivelling of the device caused by external effects are avoidable. The movement takes place slowly and in a damped manner without the user being emotionally or physically impaired.  
      Such damping elements are provided according to the invention in particular in combination with the spring mechanism, substantially in a parallel position, but may also advantageously be used by themselves alone in known holders, specifically damping such abrupt movements of vision devices from a certain position—generally the rest position—to another position—generally the operating position.  
      The spring mechanism is furthermore dimensioned so that at least partial compensation of the weight of all moving parts occurs.  
      In order to limit the pivot movement and hence to fix the end operating position of the vision device in front of the user&#39;s eye, a stop element is provided, by adjustment of which the horizontal distance of the eyepiece of the vision device from the user&#39;s eye can be adjusted in a certain range.  
      The adjusting elements by means of which the position of the vision device relative to the position of the eye of a user wearing the helmet can be established are formed in such a way that the projection of parts of the vision device beyond the head height in the rest position is minimized. This is achieved by nesting of the elements effecting the vertical and horizontal adjustment. 
    
    
      Below, the invention is described in more detail purely by way of example with reference to an embodiment.  
       FIG. 1 : shows a helmet mounted on a user&#39;s head and comprising a holder according to the invention which supports a monocular night vision device; the night vision device is present in the operating position in front of the user&#39;s eye;  
       FIG. 2 : shows a diagram corresponding to  FIG. 1 ; the night vision device is swivelled upward away from the user&#39;s eye and is in the rest position;  
       FIG. 3 : shows a view of the holder in the operating position from obliquely below (as seen by the user);  
       FIG. 4 : shows a view, corresponding to  FIG. 3 , of the holder in the operating position from obliquely above (as seen by the user);  
       FIG. 5 : shows a sectional view of the holder in the operating position;  
       FIG. 6 : shows a sectional view of the holder in the rest position;  
       FIG. 7 : shows a detailed section corresponding to  FIG. 6 ;  
       FIG. 8 : shows a sectional view perpendicular to  FIG. 5 ;  
       FIG. 9 : shows a schematic side view of the holder with indicated helmet and head of the user;  
       FIG. 10  to  13 : show developments of spring mechanisms;  
       FIG. 14  and  15 : show developments for damping elements. 
    
    
       FIG. 1  and  FIG. 2  show a holder according to the invention for a vision device, here purely by way of example a monocular night vision device  2 , which is arranged on a head covering of a user  1 , which head covering is in the form of a helmet  5 . In  FIG. 1 , the night vision device  2  is positioned in the operating position with the eyepiece  3  of the night vision device  2  in front of the eye of the user  1 ; in  FIG. 2  it is shown in the rest position, swivelled away from the field of view of the user  1 . A plate-like support element  7  having hook-like retaining brackets  16   a  is held on the edge of the helmet  5  and is connected via a tensioning strap  6  to an accessory unit  34  which is intended for holding, for example, batteries, interfaces and/or control units and which in turn is fixed to the helmet  5  by hook-like retaining brackets  16   b . The fixation by tensioning of the tensioning strap  6  is effected in the accessory unit  34  and is not described in more detail here.  
      An arm  8  which a clamping screw for the lateral adjustment  14  fixes in the position desired by the user  1  is inserted in a laterally displaceable manner in a transverse groove  35  provided on the support element  7 . The position of the arm  8  can be optionally fixed—as shown here—over the right eye or, alternatively in a second retained position  32 , over the left eye. The use of two arms  8  having a pivot mechanism  43  and adjusting elements  10 ,  11  for the use of two night vision devices  2  is also possible. It will also be possible to provide a single arm arranged in the middle of the transverse groove for holding a binocular vision device.  
      The arm  8  supports a rotatably mounted receptacle  9  to which the night vision device  2  can be coupled. The first adjusting element  10  which is vertically adjustable in the operating position, permits the vertical positioning of the night vision device  2  relative to the position of the eye of the user  1  wearing the helmet  5  and furthermore a second adjusting element  11  for the horizontal positioning of the night vision device  2  relative to the position of the eye of the user  1  are displaceably inserted into the receptacle  9 . Both adjusting elements  10 ,  11  are fixed in the position desired by the user by means of clamping screws  15  which project through slots  26  (cf.  FIG. 9 ) in the first adjusting element  10  and slots  25  (cf.  FIG. 8 ) in the second adjusting element  11  and are each locked by means of a nut  27 (cf.  FIG. 8 ).  
      The night vision device  2  is detachably fixed to the second adjusting element  11  by means of a push button  12 .  
      The night vision device  2  shown here by way of example, substantially comprises a base body  39  comprising a low light level amplifier, an objective  4  and an eyepiece  3 .  
       FIG. 2  shows the slight projection  36  of the night vision device  2  beyond the helmet  5  in the rest position. Although this may be due on the one hand to the exemplary advantageous folding of the optical assembly of the night vision device shown by way of example in  FIG. 1  and  2 , it is on the other hand—according to the invention—expedient for any—including conventional—vision device owing to the compact combined arrangement of the two adjusting elements  10 ,  11  with the pivot mechanism  43 .  
       FIG. 3  shows the support element  7  with the retaining brackets  16   a  and spacers  37 , which define the support of the support element  7  relative to the helmet, which is not shown in this diagram. For inner covering and optionally stiffening of the support element  7 , a protective covering  17  is provided. The two adjusting elements  10 ,  11  with their nesting arrangement within the receptacle  9  are clearly visible. The night vision device  2  can be coupled to/in a receptacle part  38  provided on the second adjusting element  11  and having a coupling part  23  which is intended to ensure the mechanical and electrical connection of the night vision device  2  to the holder.  
       FIG. 4  shows the arrangement of a stop element  13  which limits the pivot movement of the receptacle  9  about the arm  8 . The stop element  13  is arranged on the support element  7 , in the form of a bolt adjustable in height. The lower end  13   a  of the stop element  13 , which end is directed from the holder  13   b  of the stop element  13  towards the receptacle  9  will, depending on extension, determine the pivoting end position of the receptacle  9  in the operating position, as described in more detail further below.  
       FIG. 5  and  FIG. 6  show a section through parts of the helmet holder,  FIG. 5  showing the operating position and  FIG. 6  the rest position. A bolt  19  which is surrounded by an eye on that end of a tension spring  18  which faces the support element  7  is arranged in the arm  8 . A further eye at that end of the tension spring  18  which faces away therefrom surrounds a bolt-like lug  20   a , arranged eccentrically on a rotating element  20 . The rotating element  20  is non-rotatably connected to the receptacle  9 . In the operating position, the tension of the tension spring  18  exerts a torque on the rotating element  20  and hence on the receptacle  9 , with the result that the night vision device  2  (not shown here) is pressed against the user&#39;s head. The distance moved is limited by the stop which is formed by the stop element  13  for the receptacle  9  ( FIG. 4  and  FIG. 9 ). By—for example—rotational adjustment of the stop element  13  in its holder  13   b— having, for example a thread—the length of the end  13   a projecting from the holder  13   b  is changed, and hence the end position of the receptacle  9  in the operating position is determined. As a result, not only is there limitation of the pivoting distance from the rest position provided but at the same time a position of the eyepiece of the vision device slightly tilted in the horizontal direction relative to the user&#39;s eye can also be set.  
      All plays in the region of the bearing  33   a ,  33   b ,  33   c  ( FIG. 8 ) about the axis  20   c  of rotation are pretensioned by the spring force of the tension spring  18 , with the result that the plays are virtually undetectable even when the user experiences vibrations. If the night vision device is moved upward to the rest position, the spring  18  is tensioned. In the region of the rest position, as a result of the tension of the spring  18  and the eccentric arrangement of the bolt lug  20   a  on the rotating element  20 , the latter is moved toward the rest position and is held in this position. The rest position is likewise defined by a stop, in the example shown between second adjusting element  11  and clamping screw for the lateral adjustment  14 . A suitable design of the eccentric on the rotating element  20  and of the spring force is capable of compensating at least a part of the weight of the night vision device.  
       FIG. 5  shows the bush  23  which is inserted in the second adjusting element  11  determining the horizontal alignment of the vision device and which can be locked and unlocked by the push button  12 , and a pressure spring  22  ( FIG. 6 ) which presses the push button  12  to a rest position.  
       FIG. 5  shows the guidance of the first adjusting element  10  which effects the height adjustment of the vision device in grooves  24  in the receptacle  9  and the guidance of the first adjusting element in guides  40  which are provided in the first adjusting element  10 .  
      A transverse stiffening means  51  is arranged between the jaws of the first adjusting element  10 , with the result that both a stiffening function and a protection function against possible penetration of dirt are provided when the first adjusting element  10  is moved downward. A bush  23  is provided for the electrical and mechanical connection to the vision device to be docked.  
       FIG. 7  shows a greatly magnified sectional image in the region of the arrangement of the tension spring  18  and shows the torque variation during the movement between operating position and rest position. The direction of the torque is indicated by arrow A in the region of the operating position, by arrow R in the region of the rest position and by the double-headed arrow N in the neutral region.  
       FIG. 8  shows a section through the receptacle  9  from the front in the plane of the pivot axis. The receptacle  9  is rotatably mounted by means of bearings  33   a ,  33   b ,  33   c  on the arm  8 . These bearings are mounted in an advantageous manner for the smallest possible load during operation with vibrations over a large area and over a large diameter. A sliding bearing  31  is used for permitting mounting. The rotating element  20  with the bolt-like lug  20   a  is rotatably mounted in the arm  8  and non-rotatably connected to the receptacle  9 . Thus, the torque generated by the tension spring  18  is transmitted to the receptacle  9 , with the result that the torque variation shown in  FIG. 7  is produced. The respective extensive angular distances in which the torque is effective mean that the night vision device springs back into the previous position in the event of unintentional actuation, such as, for example, by impact.  
      In a further embodiment, a damping element is used, shown here by way of example as hydraulic rotary damper  28 . The force transmission takes place firstly from the arm  8  via a driver  29  to the outside of the damping element and secondly from the receptacle  9  via a cam  41  to the end face of the rotary damper  28 . As a result of the dynamic torque resistance of the rotary damper  28 , the speed of movement on changing the position of the night vision device  2  from the rest position to the operating position is reduced in order to avoid irritating and startling the user.  
      For protection from soiling, the arm  8  and the receptacle  9  are closed all round. In order to permit and/or simplify the mounting, openings are closed by one or more covers, for example a cover  21  for the arm  8  (cf.  FIG. 6 ) and a cover  30  coordinated with the rotating element  20 .  
       FIG. 9  shows the adjusting mode of action of the stop element  13 . This control element is screwed into the holder  13   b  arranged on the arm  8  and can be rotated by the user to cover a stop adjustment distance  42 . By screwing this stop element  13  in or out, the receptacle  9  which supports the eyepiece  3  of the night vision device  2 , shown in  FIG. 1 , is turned slightly in the operating position, with the result that the distance from the eye to the eyepiece is changed. This makes it possible for the user to carry out a fine correction of the eyepiece position in a very simple manner even with one hand.  
       FIG. 10  shows, in a further embodiment, the alternative use of a pressure spring  18   a  instead of the above-described tension spring, which is mounted between the bolt  19  and the bolt lug  20   a  of the rotating element  20  on suitable support apparatuses  49   a  and  49   b  and generates the torques according to  FIG. 7 .  
       FIG. 11  shows, in a further embodiment, the alternative use of a leg spring  18   b , which acts via the legs between a stop or bolt  19  and the bolt lug  20   a  of the rotating element  20  and generates the torques according to  FIG. 7 .  
       FIG. 12  shows, in a further embodiment, the alternative use of a cup spring assembly  18   c , which is mounted between the bolt  19  and the bolt lug  20   a  of the turntable  20  on support apparatuses  49   c  and  49   d  and generates the torques according to  FIG. 7 .  
       FIG. 13  shows, in a further, alternative embodiment, a bolt lug  20   b , formed here by way of example with a link-like engaging surface  46  for the spring  18 . Consequently, the variation of the torque and the compensation of the weight of the vision device can be adapted to different weights and centers of gravity in an advantageous manner.  
       FIG. 14  shows a further embodiment comprising a damping element in the form of a linear damper  47 . As a result, the speed is reduced in at least one direction of movement of the vision device. The linear damper may be in the form of a pneumatic spring, a pneumatic cylinder or a hydraulic shock absorber. The damping element may be provided in addition to the spring, in a plane substantially parallel to the arrangement of one of the springs  18  to  18   c  described above.  
       FIG. 15  shows, in a further embodiment, a damping element in the form of an end position damper  48 , with the result that the speed of the vision device is reduced at least in one direction of movement at the end position. The end position damper may be in the form of a buffer of resilient material. If this damping element is provided in addition to the spring, it is present in a plane substantially parallel to a plane determined by the arrangement of the springs  18  to  18   c.