Abstract:
An optical system retaining system for vision augmenting system prevents the unintended removal of the optical system but does not require disassembly of the augmenting system to remove the optical system.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 USC 119(e) of U.S. Provisional Application No. 62/253,415, filed on Nov. 10, 2015, which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Night vision systems generally comprise a number of components. A front collection lens system collects light, such as infrared light, from the environment and relays the light to a night vision tube. The collection lens system also typically provides for focus adjustment. The tube magnifies the number of received photons. In a typical tube, incoming light strikes a photocathode plate causing the emission of electrons through a microchannel plate. The electrons then form an image on a photocathode. At the proximal end, an eye piece then conditions the image for the viewer and typically provides diopter adjustment. The tube is usually contained within a housing that is threaded at either end to mate with the front collection lens system and the eye piece lens system. 
         [0003]    In general, it is not uncommon for the night vision systems to be disassembled and/or repaired and/or upgraded. For example, the collection lens system or the eyepiece lens system could become damaged through impact. Moreover, this disassembly and/or repair and/or upgrade can occur in the field and/or by untrained personnel. On the other hand, the same night vision systems must be mechanically robust such that they remain operational in harsh environments including combat conditions. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention concerns an optical system retaining system. In the current embodiment, it is used to ensure that the night vision tube collection optical system cannot be completely unscrewed from the tube housing during focusing, for example. Yet, the retaining system can be removed and then the collection system disassembled from the tube housing without having to fully disassemble the night vision tube system, for example, by removing the tube via the back or proximal side. As a result, the present system eases disassembly and mitigates the risks associated with disassembly, enabling in-field repairs or repairs by untrained personnel. 
         [0005]    In a preferred embodiment, the present invention utilizes jam rings that are inserted in front of the night vision tube collection optical system to prevent the collection optical system from becoming inadvertently completely unscrewed from the tube housing. On the other hand, these jam rings can be relatively easily removed from the front side of the system. As a result, the need to access an internal ring from the back side, necessitating removal of the night vision tube, is avoided. 
         [0006]    In general, according to one aspect, the invention features a vision augmenting system. It comprises a housing, an optical augmenting element installed within the housing, and a lens system attached to the housing and designed to be focused relative to the optical augmenting element. A detachment prevention system is used to prevent unintended removal of the lens system from the housing during focus adjustment. According to the invention, this detachment prevention system is accessible from outside of the housing. 
         [0007]    In the current embodiment, the optical augmenting element is a night vision tube, and the lens system is a collection lens system for collecting light for the optical augmenting element. The detachment prevention system then engages the lens system to prevent it from being completely unscrewed from the housing. 
         [0008]    In one example, the detachment prevention system comprises a ring that fits within a relief on the housing. This relief can be formed on an inner or outer wall of the housing. 
         [0009]    In another example, an infinity stop nut enables the indexing of a focus position of the lens system relative to the housing, and the detachment prevention system is installed on the infinity stop nut, and a ring fits within a relief on the infinity stop nut. 
         [0010]    In general, according to another aspect, the invention features a method for retaining a lens system on a vision augmenting system. This method comprises installing an optical augmenting element within a housing and installing a lens system on the housing that is designed to be focused relative to the optical augmenting element. To prevent unintended removal of the lens system from the housing during focus adjustment, a detachment prevention system is also installed. According to the invention, the detachment prevention system is installed after the optical augmenting element and the lens system have been installed in and on the housing. 
         [0011]    The above and other features of the invention including various novel details of construction and combinations of parts, and other advantages, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular method and device embodying the invention are shown by way of illustration and not as a limitation of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis has instead been placed upon illustrating the principles of the invention. Of the drawings: 
           [0013]      FIG. 1  is a cross-sectional scale view of a night vision system showing the collection optical system and tube housing, illustrating a conventional solution for retaining the collection optical system within the tube housing during operation; 
           [0014]      FIG. 2  is a scale exploded view of the night vision system showing the conventional solution for retaining the collection optical system; 
           [0015]      FIG. 3  is a scale perspective view of the night vision system showing an optical system retaining system (external jam ring) of the present invention prior to installation; 
           [0016]      FIG. 4  is a scale partial perspective close-up view showing a jam ring annular relief of the optical system retaining system; 
           [0017]      FIG. 5  is a cross-sectional scale view of a night vision tube system showing the optical system retaining system employing the external jam ring; 
           [0018]      FIG. 6  is a close-up partial cross-sectional scale view showing the external jam ring seated in the housing; 
           [0019]      FIG. 7  is a scale perspective view of the night vision system showing the optical system retaining system (internal jam ring) of the present invention; 
           [0020]      FIG. 8  is a close-up partial cross-sectional scale view showing the internal jam ring seated in the housing; 
           [0021]      FIG. 9  is a close-up partial cross-sectional scale view of a night vision tube system showing the optical system retaining system employing an infinity stop nut internal jam ring; 
           [0022]      FIG. 10  is a partial scale perspective view of the night vision system showing another embodiment of the internal jam ring of the present invention having compression tabs; and 
           [0023]      FIG. 11  is a close-up partial cross-sectional scale view showing the internal jam ring with compression tables seated in the housing. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]      FIG. 1  shows a night vision system in cross-section. 
         [0025]    In general, the night vision system  10  comprises a tube housing  200  and a collection optical system  100  mounted (screwed) on the housing  200 . Not shown is the eyepiece optical system. In operation, it would mount onto the tube housing  200  via the body eyepiece threads  214 . Also not shown is the battery pack that would mount to the battery pack mounting frame  218  of the tube housing  200 . 
         [0026]    Generally, the collection optical system  100  collects light from the environment. The light is imaged and provided to the night vision tube  212  within the tube housing  200 . This night vision tube  212  amplifies the light and provides it to the user via the eyepiece optical system, not shown. 
         [0027]    In operation, the collection optical system  100  must be focused. This occurs by the user grasping the focusing ring  110  and rotating the collection optical system  100  relative to the tube housing  200 . The rotation of the collection optical system  100  relative to the tube housing  200  causes the collection optical system  100  to move toward or away from the tube  212  by operation of a thread system. Specifically, the collection system focus threads  116  formed on the outer proximal end of the collection optical system  100  engage the body focus threads  216  formed on an internal side of a collection system mount  232  of the tube housing  200 . This enables the adjustment of the axial distance between the collection optical system  100  and the tube  212 . 
         [0028]    It is conventional to include two systems for preventing the improper focusing operation and also to facilitate focusing. First, a stop nut  118  is provided that engages threads  230  on a collection system mount  232  of the tube housing  200 . The user typically adjusts the focus position of the collection optical system  100  so that the system  10  is focused at infinity. Then, the stop nut  118  is adjusted so that its leading edge  118 -L engages the proximal surface  140  of the collection optical system  100 . The stop nut  118  is typically fixed in this position by tightening set screws, not shown, that arrest its further rotation relative to the housing  200 . This prevents the proximal end  160  of the collection optical system  100  from being driven against the distal end  220  of the tube  212 . This allows the user to adjust the collection optical system  100  to the infinity focus position quickly and repeatedly. Second, an internal ring  122  is provided that prevents the collection optical system  100  from being completely unscrewed from the tube housing  200 . Without the internal ring  122 , the user could, in seeking to focus the system, inadvertently completely unscrew the collection optical system  100  from the tube housing  200 . This is prevented by the internal ring  122 . 
         [0029]    In more detail, the internal ring  122  installs on the proximal side of the collection optical system  100 . Specifically, the internal ring  122  is threaded onto ring threads  120  on the proximal side of the collection optical system  100 . This internal ring  122  is accessible only from within the tube housing  200  only from the backside. The internal ring  122  prevents the collection optical system  100  from being completely unscrewed from the tube housing during operation by having its internal ring extension  124  come into engagement with an engagement shoulder  210  of the tube housing  200  at the maximum near focus position for the night vision tube system  10 . 
         [0030]      FIG. 2  is an exploded view showing the conventional system for retaining the collection optical system  100 . As shown during assembly, the collection optical system  100  is screwed into the body focus threads  216  to mate the collection optical signal  100  with the housing  200 . Then the internal ring  122  is installed on the collection optical system  100  through the tube housing  200  from the back side. The night vision tube  212  is inserted into the housing  200  after the internal ring  122  is installed. 
         [0031]    The general problem with this system is that removal of the collection optical system  100  necessitates the almost complete disassembly of the night vision tube system  10 . Specifically, the eye piece optical system must be removed. Then, the tube  212  must be removed from the tube housing  200 , This creates a risk of damage to these components. Further, special jigs might be required to remove the internal ring  122 . 
         [0032]      FIG. 3  shows the external jam ring embodiment of the optical system retaining system of the present invention. 
         [0033]    The external jam ring  410  is an open ring. In the illustrated embodiment it is a circular thin metal band fabricated from spring steel or an aluminum or titanium alloy. The illustrated embodiment shows three integral jam ring tabs  412  projecting radially inward from the outer thin metal band. Further, two jam ring end tabs  414  are provided on either side of the ring&#39;s opening. 
         [0034]    At the same time, a jam ring annular relief  418  is formed into the exterior wall of the nose of the collection system mount  232  of the tube housing  200  that receives the collection optical system  100 . Within the jam ring annular relief  418  are a series of jam ring tab slots  416  that correspond to angular positions of the jam ring tabs  412  and the jam ring end tabs  414  of the external jam ring  410 . 
         [0035]      FIG. 4  shows further details of tube housing  200 . Specifically, the collection system mount  232  of the tube housing  200  at its distal end has the jam ring annular relief  418 . In this relief are four separate jam ring tab slots  416  that receive the jam ring tabs  412  and the jam ring end tabs  414 . 
         [0036]      FIG. 5  shows the external jam ring  410  seated in the jam ring annular relief  418  of the collection system mount portion  232  of the tube housing  200 . The jam ring tabs  412  and the jam ring end tabs  414  project through the jam ring slots  416  to engage with a jam ring engagement shoulder portion  132  on the leading distal edge of the collection optical system  100 . As a result, mechanical interference between the jam ring tabs  412  and the jam ring end tabs  414  and this shoulder  132  prevent collection optical system  100  from becoming completely unscrewed from the tube housing  200  during an attempt to focus it. 
         [0037]    On the other hand, with relatively simple tools, such as needle nose pliers, the external jam ring  410  can be removed from the tube housing  200  allowing the collection optical system  100  to be separated from the tube housing  200  for replacement or cleaning, for example. Access from the back side, dictating removal of the tube  212 , is no longer required to remove the collection optical system  100 . 
         [0038]      FIG. 6  shows the collection optical system  100  adjusted to an infinity position where an annular distal edge  118 -L of the stop nut  118  engages with a back-side surface  140  of the focus ring  110  of the collection optical system  100 . In this position, the jam ring  410  is not engaged with the collection optical system  100 . 
         [0039]      FIG. 7  shows an internal jam ring embodiment. In one example, the internal jam ring  420  is an open ring fabricated from spring metal or potentially plastic. 
         [0040]    As shown in  FIG. 8 , the internal jam ring  420  is installed in an internal annular relief  250  formed on an internal wall of the collection system mount  232  of the tube housing  200 . When installed, the internal jam ring  420  prevents the collection optical system  100  from becoming completely unscrewed from the tube housing  200  by engaging the shoulder  132  of the collection optical tube  100 . 
         [0041]    In one embodiment, during removal of the collection optical system, the internal jam ring is removed using needle nose pliers, for example. In another embodiment, internal jam ring  420  is a consumable plastic part. Specifically, the internal jam ring  420  is removed simply by applying excessive force to unscrew the collection optical system  100  from the tube housing  200 . This results in the jam ring breaking. 
         [0042]      FIG. 9  shows an internal jam ring embodiment in which the jam ring  430  is held by the stop nut  118 . Here also, the infinity stop nut internal jam ring  430  is an open ring fabricated from spring metal or potentially plastic. 
         [0043]    The infinity stop nut internal jam ring  430  is installed in an internal annular relief  118 - r  formed on an internal wall of the stop nut  118 . In operation, the stop nut  118  is screwed onto external threads on the collection system mount of the tube housing. The infinity stop nut internal jam ring  430  prevents the collection optical system  100  from becoming inadvertently completely unscrewed from the tube housing  200  by engaging the jam ring engagement shoulder  132  of the collection optical tube  100 . 
         [0044]    Here, to remove the collection optical system  100 , the collection optical system must be unscrewed in concert with unscrewing the stop nut  118 . In this way, unintended or accidental removal of the collection optical system  100  is avoided. 
         [0045]      FIG. 10  shows another embodiment of the internal jam ring. In this example, the internal jam ring  450  is also an open ring fabricated from spring metal or potentially plastic. It includes two compression tabs  452  at either end of the open ring  450 . These compression tabs are typically bent ends of the ring  450  that are bent at  90  degrees to be parallel to a center axis of the ring  450 . 
         [0046]    The compression tabs  452  allow the ring  450  to be compressed to reduce its diameter using pliers, for example. When compressed, its diameter is small enough to fit into the bore  231  of the collection system mount  232 . The pliers can then release the tabs allowing the ring  450  to expand into the internal annular relief  250  formed on an internal wall of the collection system mount  232  of the tube housing  200 . 
         [0047]    As shown in  FIG. 11 , the internal jam ring  450  is installed in the internal annular relief  250 . When installed, the internal jam ring  450  prevents the collection optical system  100  from becoming completely unscrewed from the tube housing  200  by engaging and interfering the shoulder  132  of the collection optical tube  100  as it is being screwed out of the housing  200 . 
         [0048]    In this embodiment, during removal of the collection optical system  100 , the internal jam ring is first removed using needle nose pliers. As shown, the compression tabs  452  are long enough that they project in the distal direction, beyond the distal end  233  of the collect system mount  232 . When the collection optical system  100  is fully screwed into the housing, interference with the compression tabs  420  is avoided since they project into the depression  140 , radially inward of the proximal surface  140  of the collection optical system  100 . 
         [0049]    While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.