Abstract:
A support for adjusting the line of sight of a night vision monocular. The support has a shelf that is supported relative to a user&#39;s eyes and a flange that is coupled to the shelf and rotatable relative to the shelf. The support also has a shaft supporting the monocular. The shaft is coupled to the flange for tilting the monocular relative to the shelf concurrently with a rotation of the flange. The support also has a tilt control means coupled to the flange for applying an axial force to the flange to control the rotation of the flange and the tilting of the monocular.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit to U.S. Provisional Patent Application Ser. No. 60/450,155 filed Feb. 26, 2003, the contents of which are incorporated in this application by reference. 

   FIELD OF THE INVENTION 
   The present invention relates to a night vision device. More particularly, the present invention relates to a binocular night vision goggle for an aviator night vision imaging system that is able to maintain the line of sight during operation. 
   BACKGROUND OF THE INVENTION 
   A conventional binocular night vision device uses a pair of monocular night vision scopes which are mounted and associated with one another in such a way as to provide the user of the device with binocular vision, thereby allowing the user to have a night-time view with depth perception.  FIG. 1  shows a night vision device  10  including a pair of night vision monoculars  12  which can be suspended in front of a user&#39;s eyes by an elongated shelf  14  which has a laterally rectangular shape in plan view, and is also of a generally rectangular shape in both frontal and side elevation views. Depending from the shelf  14  is a pair of spaced apart mounts  16  (best seen in  FIG. 7   b ).  FIG. 2   a  shows a top view of shelf  14  without the binocular mounted onto it.  FIG. 2   b  shows a bottom view of shelf  14  without the binocular mounted to it. 
   The interpupillary distance (IPD) is defined as the distance between the user&#39;s pupils. In order to allow adjustment of the horizontal spacing between the monoculars  12  to match the interpupillary distance (IPD) of a user, an IPD adjustment mechanism moves the monoculars toward each other and away from each other. Part of the IPD mechanism is located on the outside of shelf  14  and part of it is located between walls of shelf  14 . The walls are underneath shelf  14 . 
   As shown in  FIGS. 2   b  and  3 , the underneath part of shelf  14  is divided into three sections  34 ,  36 ,  38  by four walls  18 ,  20 ,  22 , and  24 . A circular aperture is located inside each of the walls. Aperture  18   a  is located in wall  18 , aperture  20   a  is located in wall  20 , aperture  22   a  is located in wall  22 , and aperture  24   a  is located in wall  24 . Rotatably received in the apertures  18   a ,  20   a ,  22   a ,  24   a  are flanges  18   b ,  20   b ,  22   b , and  24   b  of an eccentric shaft  26 . Eccentric shaft  26  is a thin elongate blade portion. Inside each of the flanges  18   b ,  20   b ,  22   b ,  24   b  are off-center apertures  18   c ,  20   c ,  22   c , and  24   c . A pivot lever  28  of the eccentric shaft  26  is part of flange  18   b  and extends outwardly of one end of the shelf  14 . 
   Rotatably received in apertures  18   c  and  20   c  is an IPD threaded shaft  30 . A monocular (not shown) is mounted onto IPD threaded shaft  30 . One end of IPD threaded shaft  30  extends through aperture  18   c  in flange  18   b , which is in aperture  18   a  of wall  18 . Consequently, this end of IPD threaded shaft  30  extends from the space in section  36  at the underside of shelf  14  to the outside of wall  18 . The other end of IPD threaded shaft  30  extends through aperture  20   c  in flange  20   b , which is in aperture  20   a  of wall  20 . Consequently, this end of IPD threaded shaft  30  extends from space  36  at the underside of shelf  14  into the space in section  38  at the underside of shelf  14 . 
   Rotatably received in apertures  22   c  and  24   c  is an IPD threaded shaft  32 . Another monocular (not shown) is mounted onto IPD threaded shaft  32 . One end of IPD threaded shaft  32  extends through aperture  24   c  in flange  24   b , which is in aperture  24   a  of wall  24 . Consequently, this end of IPD threaded shaft  32  extends from the space in section  34  at the underside of shelf  14  to the outside of wall  24 . The other end of IPD threaded shaft  32  extends through aperture  22   c  in flange  22   b , which is in aperture  22   a  of wall  22 . Consequently, this end of IPD shaft  32  extends from space  34  at the underside of shelf  14  into the space in section  38  at the underside of shelf  14 . 
   The end of IPD threaded shaft  32  that extends into space  38  from space  34  is threaded and carries a washer member  40  which is secured axially on the IPD threaded shaft  32  by a threaded nut  42 . Consequently, IPD threaded shaft  32  cannot move out of aperture  22   c  in flange  22   b . The end of IPD threaded shaft  30  that extends into space  38  from space  36  is threaded and carries a washer member (not shown) which is secured axially on the IPD threaded shaft  30  by a threaded nut (not shown). Consequently, IPD threaded shaft  30  cannot move out of aperture  20   c  in flange  20   b.    
   The end of IPD threaded shaft  32  that extends from space  34  to the outside of wall  24  is attached to a control knob  40 . The end of IPD threaded shaft  30  that extends from space  36  to the outside of wall  18  is attached to a control knob  42 . Each of the monoculars is respectively coupled to the IPD shafts  30  and  32 . Control knobs  40  and  42  may be rotated independently of each other. When control knobs  42  and  40  are rotated, they may respectively cause IPD shafts  30  and  32  to rotate thereby moving the monoculars toward and away from each other to adjust for varying eye separations. 
   As explained above, lever  28  is part of flange  18   b . Each of the flanges are connected together by the eccentric shaft  26 . Each of the flanges has an off-center aperture. Off-center apertures  18   c  and  20   c  receive IPD threaded shaft  30  and off-center apertures  22   c  and  24   c  receive IPD threaded shaft  32 . Rotation of lever  28  rotates eccentric shaft  26 , flanges  18   b ,  20   b ,  22   b , and  24   c , shaft  30  and shaft  32  relative to shelf  14 . Since each of monoculars are coupled to shafts  30  and  32 , rotation of lever  28  tilts each of the monoculars relative to shelf  14  and relative to a user&#39;s eyes. Thus, the main purpose of the eccentric shaft  26  and its associated flanges is to provide a means of tilting the line-of-sight of the two monoculars simultaneously. The lever may be used to adjust the tilt of the monoculars to align with the user&#39;s line-of-sight. 
   As shown in  FIG. 3 , the conventional eccentric shaft uses an o-ring  46  to provide rotational friction between the eccentric shaft  26  and the shelf  14 . The o-ring  46  is placed in a groove  18   d  of flange  18   b , near adjustment lever  28 . After the eccentric shaft is assembled to the shelf assembly, the purpose of the o-ring is to provide frictional resistance against the shelf. The rotational friction force occurs between o-ring  46  and aperture  18   a  of wall  18  when flange  18   b  is inserted into aperture  18   a . Thus, the o-ring acts as a frictional resistor between the eccentric shaft and the shelf. The frictional interface between o-ring  46  and aperture  18   a  is controlled by tight tolerances between flange  18   b  of the eccentric shaft  26 , the shelf  14 , and the o-ring  46 . One of the purposes of the rotational friction provided by the o-ring is to minimize or prevent the night vision binocular from inadvertently tilting because of vibration during operation. Another purpose is to provide a smooth resistance during adjustment. 
   However, it is possible for the eccentric shaft to rotate during vibration and overcome the frictional resistance provided by the o-ring. This can cause the night vision goggles&#39; optical axis to tilt downward. 
   It is therefore necessary to provide a design that prevents, or at least better inhibits, the eccentric shaft from rotating during operation. 
   SUMMARY OF THE INVENTION 
   A support for adjusting the line of sight of a night vision monocular. The support has a shelf that is supported relative to a user&#39;s eyes and a flange that is coupled to the shelf and rotatable relative to the shelf. The support also has a shaft supporting the monocular. The shaft is coupled to the flange for tilting the monocular relative to the shelf concurrently with a rotation of the flange. The support also has a tilt control means coupled to the flange for applying an axial force to the flange to control the rotation of the flange and the tilting of the monocular. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a prior art binocular night vision goggle. 
       FIG. 2   a  is a top perspective view of a prior art shelf for supporting a binocular night vision goggle. 
       FIG. 2   b  is a bottom perspective view of a prior art shelf for supporting a binocular night vision goggle. 
       FIG. 3  is an exploded perspective view of a prior art shelf, eccentric shaft, and o-ring. 
       FIG. 4  is a perspective view of a binocular night vision goggle showing brackets for attaching a heads-up display assembly. 
       FIG. 5  is a perspective view of a heads-up assembly that may be attached to a binocular night vision assembly. 
       FIG. 6  is a perspective view of an eccentric shaft with improved means to couple the eccentric shaft to the shelf. 
       FIG. 7   a  is a perspective view of the shelf, part of the heads-up display, and the improved means to couple the eccentric shaft to the shelf. 
       FIG. 7   b  is a perspective view showing how the binocular night vision assembly is coupled to the shelf and part of the heads-up display. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention. 
   The problems with the conventional device are intensified when a Heads-Up Display (HUD) is attached to the monocular&#39;s objective lens during use.  FIG. 4  shows night vision binoculars  10  with a heads up display  100  mounted on top of shelf  14 . Heads up display  100  is centered on shelf  14 . Therefore, heads up display  100  does not cause the shelf to tilt during operations.  FIG. 5  shows a second type of heads up display  150  that can be attached to the night vision binoculars. Heads up display  150  includes an adjustable circular frame  152  which may fit over objective  11  of a night vision monocular  10 . Adjustable circular frame  152  may be affixed to objective  11  with bolt and nut configuration  154 . HUD  150  is therefore attached to the front of the objective end of monocular  12  and part of the HUD extends out over the front of the objective end of the night vision goggle. These two aspects of the HUD result in additional weight and additional downward force components that must be restrained. 
   In the prior art device, the eccentric shaft is assembled by inserting an eccentric shaft into the shelf and then fastening the IPD threaded shafts to the shelf assembly using locking nuts. The eccentric shaft is held to the shelf assembly by the IPD threaded shaft and locking nut. The torque placed on the IPD threaded shaft and locking nut, and likewise on the eccentric shaft, can be inconsistent depending on the torque applied by the person assembling the device. The result of this method of assembling the shelf to the IPD threaded shaft is that either the IPD or line-of-sight tilt can be altered by an adjustment of one of these components. That is, the IPD can change by adjusting the line-of-sight and the line-of-sight can change by adjusting the IPD. This alteration of adjustment in either IPD or line-of-sight tilt is undesirable since one adjustment should not alter another inadvertently. The tendency of the line-of-sight to change is increased by the weight added by HUD  154 . 
   The present invention overcomes the aforementioned difficulties caused by the HUD by adding the capability for the eccentric shaft to be assembled to the shelf independent of the IPD threaded shafts and locking nuts. That is, the IPD threaded shafts and locking nuts are not needed to hold the eccentric shaft to the shelf. The main connection force is applied through a nut and washer that is located on the outside of the shelf. 
   The method of assembly also allows a settable force to be applied axially to the eccentric shaft, thereby increasing the friction between the eccentric shaft and the shelf. The additional friction helps to prevent the possibility of the night vision goggles&#39; monoculars from inadvertently changing the line-of-sight tilt adjustment during operations, even when a HUD is attached to one of the night vision goggles&#39; objectives. This solution also reduces the possibility of the line-of-sight tilt adjustment from changing due to IPD adjustment. This is due to the increased torque between the eccentric shaft and the shelf. 
   The solution involves a modification of the eccentric shaft and the inclusion of a tilt control means comprising two additional parts, a spring washer and a locking nut. The incorporation of these additional components greatly improves the ability of the eccentric shaft to hold the desired line-of-sight during vibrations. The improved eccentric shaft design overcomes the problems of the prior art by providing a settable force level between the eccentric shaft and the shelf. 
   Referring to  FIG. 6 , an eccentric shaft  60  is shown having four round flanges  62 ,  64 ,  66 ,  68 , having off-center apertures  62   a ,  64   a ,  66   a ,  68   a . The length of eccentric shaft  60  is the same as the length of eccentric shaft  26  in the prior art. Therefore, eccentric shaft  60  may be used with the prior art shelf  14 . The shape and diameters of flanges  62 ,  64 ,  66 , and  68  are the same as apertures  18   a ,  20   a ,  22   a , and  24   a . Therefore, flanges  62 ,  64 ,  66 , and  68  may also be used with the prior art shelf  14 . Flange  68  of eccentric shaft  60  is the flange located at the far end of the eccentric shaft away from lever  28 . It has the same shape and diameter as flange  24   b  in the prior art and therefore may be inserted into aperture  24   a.    
   Flange  68  is made thicker than flange  24   b  had been in the prior art. Because the thickness of flange  68  has been increased compared to the prior art, the thickness of flange  66  has been decreased in comparison to flange  22   b  in the prior art. The amount of decreased thickness of flange  66  is equal to the amount of increased thickness of flange  68 . The thickness of flange  66  matches the width of wall  22 . The incorporation of offsetting thicknesses allows the length of eccentric shaft  60  to remain the same as the length of eccentric shaft  26  so that the improved eccentric shaft may be incorporated into a conventional shelf. Flange  68  is threaded and is made thick enough so that the threads protrude outside of wall  24 . 
   During the assembly of the eccentric shaft to the shelf, a spring washer  70  and a locking nut  72  are added to the threaded surface of flange  68 . Washer  70  is placed over the threads of flange  68  that extend outside of wall  24  and abuts wall  24 . Nut  72  threads onto the threads on flange  68  and abuts washer  70 . Therefore, washer  70  is placed between wall  24  and nut  72 . In an exemplary embodiment, the spring washer may be a wave washer, a Belleville washer or other locking washer. In an alternative embodiment, the shelf may be made out of plastic and the plastic shelf may be used as a spring mechanism. 
   In the conventional shelf and flange, the flexibility of the o-ring changed over time, becoming hard in cold weather and soft in warm weather. In addition, it was subject to wear over time. In addition, the torque placed on the IPD threaded shaft, locking nut, and eccentric shaft was inconsistent because it depended on the torque applied by the person assembling the unit. In the present invention, the locking nut and the washer place a consistent strong frictional force between the locking and the washer during the rotation of the eccentric shaft in relation to the shelf. The spring washer limits the variation of tension and force over time despite the presence of varying environmental conditions. The new method of retention allows a settable force to be applied axially to the eccentric shaft thereby increasing the friction between the eccentric shaft and the shelf. This additional friction helps to prevent the possibility of the night vision goggles&#39; monoculars from inadvertently changing the line-of-sight tilt adjustment during operations, even when a HUD is attached to one or more of the night vision goggles&#39; objectives. 
   Washer  70  prevents wall  24  from wearing out over time from the rotation of nut  72 , as it is rotated by lever  28  and the eccentric shelf. If wall  24  were allowed to wear, the tension applied to the eccentric shaft and to wall  24  of the shelf would be changed dramatically over time. Instead, the washer absorbs all of the rotational friction that is applied by nut  72  and little or no rotational friction is applied to wall  24 . 
   In an exemplary embodiment, the eccentric shaft may be assembled to the shelf without an o-ring on flange  62 . In an alternative embodiment, the eccentric shaft may be assembled to the shelf with an o-ring on flange  62 . 
   In the conventional design, the force needed to rotate lever  28  on the eccentric shaft once the eccentric shaft is assembled to the shelf is approximately 0.7 pounds. In the design disclosed herein, the forced needed to rotate lever  28  is in a range of 2.4 to 3.5 pounds. Accordingly, the present invention has increased the force needed to rotate the eccentric shaft approximately three to five times. This increase in needed force is an important factor in preventing the inadvertent changing of the line-of-sight adjustment once it is set. 
   Although illustrated and described above with reference to certain specific embodiments and examples, the present invention is nevertheless not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention. For example, the invention may be applied to a night vision monocular, to a monocular that may be used during daylight or other conditions that are not dark, and to a binocular that may be used during daylight or other conditions that are not dark.