Abstract:
A method of making a rifle scope that utilizes a mounting assembly that includes a longitudinal base plate and a mating, closure housing piece. Separate optical assemblies are attached to the base plate to form an optical train of optical assemblies, extending longitudinally along the base plate, to form an image magnifying assembly. Also, at least some of the optical assemblies include a support and an optical element and an adjustment feature permitting adjustment of position of the optical element relative to the base plate. In the method, at least one of the adjustment features is used to adjust position of one of the optical elements, relative to the base plate, and wherein the optical element is then permanently fixed in place. Finally, the mating, closure housing piece is attached to the longitudinal base plate and the closure housing piece is fastened to the base, thereby forming a rifle scope.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of application Ser. No. 12/859,623, filed Aug. 19, 2010, now U.S. Pat. No. 8,599,481, which is a continuation-in-part of application Ser. No. 12/626,316, filed Nov. 25, 2009, now U.S. Pat. No. 8,379,307, which claims priority from provisional application 61/274,698 filed Aug. 20, 2009. This application also claims priority from provisional application 61/295,849 filed Jan. 18, 2010. All three of these applications are incorporated by reference as if fully set forth herein. 
     
    
     BACKGROUND 
       [0002]    The principal paradigm of telescopic rifle sight production is production on the lathe. Although this facilitates the centering of the scope components, the resultant scope housing must be round in transverse section. There may be some instances in which a scope that is round in transverse section is not optimal. 
         [0003]    One difficulty in assembling a scope is the need to critically adjust the distance between the lenses of the scope, so that the reticle is in focus at every power of magnification. In a standard tube housing scope it may be challenging to make some of these adjustments, because of a lack of space. Also, in a standard tube housing scope there is a shortage of space for some of the inner workings, forcing in some cases the use of thinner walled materials than is desirable. 
       SUMMARY 
       [0004]    In a first separate aspect, the present invention may take the form of a method of making a rifle scope that utilizes a mounting assembly that includes a longitudinal base plate and a mating, closure housing piece. Separate optical assemblies are attached to the base plate to form an optical train of optical assemblies, extending longitudinally along the base plate, to form an image magnifying assembly. Also, at least some of the optical assemblies include a support and an optical element and an adjustment feature permitting adjustment of position of the optical element relative to the base plate. In the method, at least one of the adjustment features is used to adjust position of one of the optical elements, relative to the base plate, and wherein the optical element is then permanently fixed in place. Finally, the mating, closure housing piece is attached to the longitudinal base plate and the closure housing piece is fastened to the base plate, thereby forming a rifle scope. 
         [0005]    In a second separate aspect, the present invention may take the form of a rifle scope that includes a longitudinal base plate and a set of optical assemblies each including a support element and at least one optical element, attached to the longitudinal base plate to form an optical train of optical elements, extending longitudinally along the longitudinal base plate, to form an image magnifying assembly. Also, at least some of the optical assemblies an adjustment feature that permitted adjustment of longitudinal position of the optical element relative to the base plate, the optical elements, however, being now permanently fixed in place, rendering the adjustment feature no longer useable. Finally, a closure housing piece is fastened to the longitudinal base. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Exemplary embodiments are illustrated in referenced drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. 
           [0007]      FIG. 1  is a top perspective view of a work piece representing a stage in a preferred method of production according to the present invention. 
           [0008]      FIG. 2  is a top perspective view of the work piece of  FIG. 1 , at a further stage in a preferred method production according to the present invention. 
           [0009]      FIG. 3  is a bottom cut-away view of the work piece of  FIG. 1 , showing the elevation knob cover open. 
           [0010]      FIG. 4  is a bottom cut-away view of a portion of the work piece of  FIG. 3 , showing the elevation knob cover closed. 
           [0011]      FIG. 5  is a top perspective view of the work piece of  FIG. 2 , at a further stage in a preferred method production according to the present invention. 
           [0012]      FIG. 6  is a top perspective view of the work piece of  FIG. 5 , at a further stage in a preferred method production according to the present invention. 
           [0013]      FIG. 7  is a top-front perspective view of a dual mode rifle sight, constructed as shown if  FIGS. 1-6 . 
           [0014]      FIG. 8  is a top-rear perspective view of the rifle sight of  FIG. 7 . 
           [0015]      FIG. 9  is a longitudinal sectional view of the rifle sight of  FIG. 7 . 
           [0016]      FIG. 10  is a perspective view of an alternative embodiment of a rifle sight according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]    In broad overview, the present invention may take the form of a method of constructing a rifle sighting system  8  ( FIGS. 7 and 8 ), which in one preferred embodiment begins (see  FIG. 1-4 ) with a work piece  10 , which in its first form is a mounting assembly  12 . Assembly continues with the attachment of a mode switching and ocular assembly  14  ( FIG. 2 ), which switches the scope between a reflex sight mode and a telescopic sight (scope) mode and also presents the imagery to a viewer. In addition a zoom assembly  16  ( FIG. 5 ) is attached. Assembly  16  has the function of user actuated variable magnification (that is, “zoom”) and also is tilted to introduce an elevation angle for bullet drop correction and a windage angle. Finally an objective lens and Petzval assembly  18  ( FIG. 6 ) is mounted, to accept light for the telescopic portion of the scope and to refract this light in accordance with the overall optical scheme. Finally, a cover  20  ( FIGS. 7 and 8 ) is placed on the work piece and fastened securely in place, to create a finished sighting system  8 . In addition to various elements described below,  FIGS. 7 and 8  show a windage knob  21 , the operation of which will be familiar to skilled persons and the action of which is identical with elevation knob  38 , which is discussed below. In an alternative preferred embodiment, cover  20  is made up of two cover pieces as it is divided along one of the transverse lines shown in  FIGS. 7 and 8 . Two cover pieces may also be used to form a sight that has less of a regular shape. 
         [0018]    The method of constructing a rifle sight  8  by attaching a set of pre-built assemblies to a mounting assembly divides the assembly process into smaller and more easily automated tasks. Also, this method permits a design having more space for the zoom assembly, permitting a stronger construction of this assembly that is therefore better able to withstand recoil shock. Finally, designs are permitted that more easily accommodate other internal parts, such as internal portions of actuator assemblies. 
         [0019]    In greater detail of mounting assembly  12 , a mounting plate  22  is adapted to receive optical assemblies, as will be described below. A rifle mounting fixture  24  supports mounting plate  22  and is adapted to permit the finished scope  8  to be attached to a rifle (not shown). Mounting plate  22  includes many mounting features, such as a set of fastener-receiving holes  26  to permit the mounting of optical assemblies and other elements. Also, a front indentation  28  helps guide the placement of the objective assembly  18  ( FIG. 6 ) and in use helps absorb the shock of recoil, which over time may damage fasteners. A rear, essentially square through-hole  30  ( FIG. 1 ), is adapted to host a light emitting diode (LED) based reflex sight reticle  29  ( FIG. 9 ). A set of long threaded apertures  31  ( FIG. 1 ), permit adjustment screws  33  ( FIG. 9 ) to be used to make small changes to the position of the reflex reticle  29 . Skilled persons will readily recognize that features  28 ,  30  and  31  may be machined into mounting plate  22 , which can also be termed a base plate (see below) or a longitudinal base plate as plate  22  has a length, defining a longitudinal dimension, which is substantially longer than its width. In one embodiment features  38 ,  30  and  31  are formed by machining. 
         [0020]    At the stage of production shown in  FIG. 1 , a cam tube-turning gear  32  and an arm  34  that rotates gear  32  are already attached to plate  22 . Also, a dual mode switching-lever  36  is hinged to plate  22 . Additionally present is an elevation angle actuator knob  38 , which is protected against accidental contact by a knob cover  39  (see also  FIGS. 3 and 4 ). In turn, cover  39  is retained by a sliding latch  40 . In a preferred embodiment, a cam tube base support  42  is part of plate  22 , and a cam tube side support  44  is fastened to plate  22 . An elevation adjustment post  48 , driven by actuator knob  38 , protrudes from an aperture in support  42 , and as will be familiar to skilled persons, is used to change the elevation angle of the cam tube assembly  16 . Referring to  FIG. 2 , pre-built mode switching and ocular assembly  14  is installed at the rear of mounting assembly  20  using fastener apertures  26 . In addition, dual mode switching lever  36  is connected to assembly  14 . 
         [0021]    Referring to  FIG. 5 , in a next step in the assembly process, a cam tube assembly  16 , including a cam tube assembly holder  62 , is installed, by bolting holder  62  onto plate  22 , using bolts that come up through plate  22  into threaded holes in holder  62 . The front portion of assembly  16  rests on cam tube elevation post  48  and cam tube side support  44 . The gear  32  meshes with a cam tube assembly gear  64  to turn assembly  16 . Base plate  22  defines an opening through which a pin  68  ( FIG. 9 ) extends connecting arm  34  to gear  32 . This opening is only required to be large enough to accommodate pin  68 , which fits snugly. As a result, scope  8  is sealed tightly against outside elements, which are not afforded an opportunity for entry by the zoom actuator (collectively arm  34 , pin  68  and gear  32 ). Spring  70 , connecting fixed arm  71  with connected to mirror  90  ( FIG. 9 ), urges mirror  90  to quickly move to its correct position during switching of lever  36  (see discussion of  FIG. 9 ). 
         [0022]    Referring to  FIG. 6 , an objective and Petzval lens assembly  18  is fit into recess  28  and attached using apertures  26 . An objective lens support  72  hosts a set of objective lenses  74 , a lens-protective clear sheet  75 , and a Petzval support  76  hosts Petzval lens holder  78  that, defining slots  82 , in turn holds Petzval lens  80 . Additionally, assembly  18  includes a set of braces  84  which retain the front of cam tube assembly  16 , in cooperation with elevation post  46  and side support  44  or windage post (not shown). 
         [0023]    Referring to  FIGS. 7 and 8 , the cover  20  is placed over assemblies  14 ,  16  and  18  and connected to plate  22  by fasteners placed through base plate cover fastening apertures  92  and into apertures (not shown) defined in the bottom of the sides of cover  20 . The housing of sight  8  is formed from the fastened together combination of plate  22  and cover  20 . Cover  20  defines a reflex sight window  114  and an image presentation window  116 . A reflex reticle brightness adjustment knob  120  is electrically connected to reflex reticle  29 . 
         [0024]    Referring to  FIG. 9 , assemblies  14 ,  16  and  18  cooperate together to provide a dual mode reflex/telescopic sight  8  having a user controlled variable magnification (also referred to as “zoom”). Lever  36  ( FIGS. 5 and 6 ) is operatively connected to and changes the position of a moveable mirror  90 ,  90 ′, between a reflex sight mode position  90  and telescopic sight mode position  90 ′. In reflex sight mode position, light from the light emitting diode (LED) reflex sight reticle  29 , housed in square aperture  30 , is reflected from mirror  90  and through a first ocular lens  94 . The reticle light is then reflected from a fixed mirror  96  and travels through a second ocular lens  98 . This light is then reflected from the reflex sight window  114 , the back side of which is reflective for the red light of the reflex sight reticle, through image presentation window  116  to the user. Accordingly the reticle image is superimposed upon the view from window  114 . In telescopic sight mode, the moveable mirror  90  is in telescopic sight mode position  90 ′, where it blocks the light from window  114  and reflects the light that has traveled through zoom assembly  16 , including a reticle  67 , and ocular assembly  14 . 
         [0025]    Assembly  16  includes a pair of lens groups  121 , each of which is held in a lens holder  122  that supports a slot-follower  124 . Lens groups  121  are supported by two concentric tubes, an inner tube  126  and a cam tube  128 , concentric with and supporting inner tube  126 . Inner tube  126  defines a straight longitudinal slot(not shown), whereas cam tube  128  defines curved cam-slots  132 . Slot-followers  124  each engage with both the straight longitudinal slot and one of slots  132 . Accordingly, as cam tube  128  is turned by gear  32 , lens groups  121  move forward or backward, but retain their orientations. 
         [0026]    Referring to  FIG. 10 , in an alternative preferred embodiment, cam tube  128  is turned by a gear  140  driven by an electric motor, inside a housing  142 , and actuated by a button  144 . The electric motor may be supported by a set of springs or resiliently deformable material with housing  130 , to protect the motor against recoil shock. 
         [0027]    One advantage of the method of the present invention is that assemblies  14 ,  16 , and  18  may be constructed and tested separately, thereby dividing the assembly task into three simpler tasks of sub-assembly construction, which may be automated, and a final assembly that requires only the installation of the three assemblies, and final testing and adjustment. Final test and adjustment is critical, however, so that the reticle will be in focus at every variable magnification level. 
         [0028]    Assemblies  14  and  18  include features designed to facilitate the final adjustments. Skilled persons will readily recognize that assembly  14  may be characterized as being made of an objective lens sub-assembly that includes elements  72  and  74 , a Petzval lens sub-assembly that includes elements  76 ,  78 ,  80 , and  82  and the spacer plate shown in  FIG. 6 , connecting the two subassemblies. Further,  FIG. 6  shows that this spacer plate is shaped to fit into indent  28 . The Petzval lens holder  78  has a threaded exterior that engages with a threaded interior of support  76 , and may be moved forward or rearward by rotation. Slots  82  accept a tool to facilitate such rotation. After this adjustment, the position of holder  78  is fixed by adhesive in support  76 . Similarly, ocular lens  94  is mounted onto holder  150 , which is fastened by threaded fasteners to a base (support)  152 . During assembly a technician positions lens  94  by moving holder  150  as he looks through the image presentation window  116  until the telescopic reticle (not shown) appears clearly in focus at −¾ diopters. After holder  150  is correctly positioned, a number of fasteners, including one from the front that acts as a hard stop during recoil, are utilized to keep holder  150  and lens  94  securely in place. 
         [0029]    It should be emphasized that although the preferred embodiment shown is a dual mode reflex/telescopic sight  8 , that the method of constructing a scope is equally applicable to a single mode telescopic sight, or stated in more familiar terms, a rifle scope. Skilled persons may now appreciate some of the advantages of the present design. Each of the three assemblies  14 ,  16  and  18  may be assembled and tested prior to final assembly, thereby reducing the critical tasks of final assembly to the installation of these three assemblies into the prepared attachment locations and final adjustments. 
         [0030]    In prior art scope assemblies, a difficulty is encountered in attaching a typical round scope to an essentially flat mounting rail. The mounting rings used to solve this problem create their own problems by limiting the areas available for scope controls. A conflict is sometimes encountered between the location of the scope controls and the mounting rings. The present design entirely eliminates this problem, by eliminating the need for mounting rings. 
         [0031]    The basic design of the zoom actuator (arm  34 , gear  32  and gear  64 ), may be used for rifle scopes having differing configurations. For example, in an alternative preferred embodiment, the same construction techniques are used to build a scope having a focus adjustment. In this case, however, the arm may turn a noncircular gear, to achieve a nonlinear relationship between arm movement and focus lens movement. 
         [0032]    One problem encountered in prior art scope design is that of the lack of transverse space available for the cam tube and the pivot tube (generally analogous to cam tube  128  and inner tube  126  of the present preferred embodiment, but with various permutations, such as the cam tube being nested inside the pivot tube. This lack of space led to cam tube designs with wall thickness of less than a millimeter, leaving the cam tube vulnerable to damage from the slot followers during recoil. The present design does not put a transverse space limitation on cam tube and pivot tube wall thicknesses, making for a more robust design with wall thicknesses of 1 mm or greater. Accordingly with this basic manufacturing scheme, scopes can be made that are able to withstand the recoil of more powerful rifles, such as .50″ caliber rifles. 
         [0033]    Moreover, many additional preferred embodiments utilize the interior space made available through the construction techniques of the present method. In one design, electric motors directly move the lens groups in the zoom assembly, thereby creating a greater range of possible zoom ratios. 
         [0034]    While a number of exemplary aspects and embodiments have been discussed above, those possessed of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.