Abstract:
A locking turret knob includes an adjustment member, a first member, and a second member. The adjustment member is adjustably positionable about an axis of rotation. The first member is disposed in proximity to the adjustment member and has at least one engagement member. The second member is disposed in proximity to the adjustment member and has at least one engagement surface. The adjustment member is adjustably positionable about the axis of rotation when each engagement member does not engage an engagement surface. The adjustment member is locked in a selected position about the axis of rotation when at least one engagement member engages an engagement surface. The adjustment member can be coupled to an adjuster of an optical enhancement device, such as a telescopic sight, a telescope or a microscope.

Description:
RELATED APPLICATIONS 
     This application is a continuation of and claims priority to U.S. application Ser. No. 13/220,525, filed Aug. 29, 2011, now U.S. Pat. No. 8,516,736, which is a continuation of application Ser. No. 11/720,428, filed May 29, 2007, now U.S. Pat. No. 8,006,429, which is a national phase entry of International Application No. PCT/US2005/043336, filed Nov. 30, 2005, which claims the benefit of U.S. Provisional Application No. 60/632,331, filed Nov. 30, 2004, and U.S. Provisional Application No. 60/638,561, filed Dec. 22, 2004. The entire teachings of each of the above applications are incorporated by reference herein. 
    
    
     BACKGROUND 
     The present disclosure relates to an optical enhancing device, such as a telescopic observation sighting device or individual shoulder (or hand-fired) firearms sighting device (telescopic sight herein). Embodiments described herein may also be used with any optical enhancing device containing adjusters, such as a microscope, telescope, etc. For purposes of illustration, it will be assumed herein that the optical enhancing device is a telescopic sight. 
     A telescopic sight, typically used to aim a firearm, is usually mounted on the firearm. An adjustment knob on a telescopic sight is typically used for changing a setting of an adjuster that may change the adjustment of, for example, elevation, crossrange (also “windage” herein), or parallax of the telescopic sight. Parameters such as elevation, crossrange, and parallax, may be painstakingly set in order that the firearm hit a specific target. Once set for a particular target, the setting preferably remains unchanged until after a shot is fired. 
     Existing telescopic sighting systems for civilian, law enforcement, and military firearms typically utilize one or more of three types of adjustment knobs. The first type of adjustment knob, termed a “hunting style” knob, utilizes a cover cap that must be removed prior to adjustment of the sight and replaced after adjustment of the sight to protect the adjustment member of the knob from unintentional adjustment. An advantage of this style of adjustment knob is that it is protected from moisture due to the protection provided by the cover cap. A disadvantage of this type of adjustment knob is that for each adjustment, the cap must be removed and replaced, thereby creating a potential for cap loss. 
     The second type of adjustment knob is termed a “target style” knob, and is accessible for adjustment at all times. An advantage of this type of adjustment knob is that it is accessible for adjustment at all times without the necessity of removing and replacing a cover cap. A disadvantage is that the adjustment knob can be inadvertently rotated by accidental physical contact. 
     The third type of adjustment knob is a variation of the “target style” adjustment knob and is a replacement knob used in lieu of the “hunting style” turret knob protective cap. This style of adjustment knob provides a “target style” function, should a marksman choose its use. The advantages and disadvantages of this type of adjustment knob are the same as for the “target style” knob. 
     What is needed is an adjustment knob that is mechanically lockable, and can be unlocked by an operator when a change in setting is desired. 
     SUMMARY 
     According to one embodiment, an adjustment knob is mechanically lockable and can be unlocked by an operator when a change in setting is desired. In particular, a locking turret knob may include an adjustment member, a first member, and a second member. The adjustment member is adjustably positionable about an axis of rotation. The first member is disposed in proximity to the adjustment member and has at least one engagement member. The second member is disposed in proximity to the adjustment member and has at least one engagement surface. The adjustment member is adjustably positionable about the axis of rotation when each engagement member does not engage an engagement surface, and the adjustment member is locked in a selected position about the axis of rotation when at least one engagement member engages an engagement surface. The adjustment member can be coupled to an adjuster of an optical enhancement device, such as a telescopic sight, a telescope or a microscope. A change in the selected position of the adjustment member produces a change in an adjustment setting of the adjuster of the optical enhancement device. 
     In one embodiment, the first member is fixably coupled to the adjustment member. In another embodiment, the second member is fixably coupled to the adjustment member. 
     The at least one engagement surface may be an aperture and the at least one engagement member may be a protuberance, such as a pin member, that engages the aperture. In another embodiment, the at least one engagement surface is part of a spline structure. For example, the at least one engagement member can be part of a spline structure that engages the engagement surface of another spline structure. As another example, at least one engagement member can be a protuberance that engages the engagement surface of another spline structure. 
     According to one embodiment, the adjustment member becomes unlocked in response to application of a force and is adjustably positionable to a newly selected position about the axis of rotation. Accordingly, the adjustment member becomes locked in the newly selected position about the axis of rotation in response to removal of the force. 
     A locking selection member may be coupled to the first member. The locking selection member is responsive to a force, such as a pulling force or a pushing force, applied to the locking selection member by causing each engagement member of the first member to disengage each engagement surface of the second member. When the force is removed or another force is applied, the locking selection member enables each engagement member of the first member to engage a corresponding engagement surface of the second member. One alternative embodiment provides that the force rotates the locking selection member when the force is applied in a first rotational direction. Accordingly, when the force is removed and when a second force is applied to the locking selection member in a second rotational direction, the locking selection member enables at least one engagement member of the first member to engage a corresponding engagement surface of the second member. 
     A method of manufacturing a locking turret knob may include providing an adjustment member adjustably positionable about an axis of rotation, providing a first member disposed in proximity to the adjustment member and having at least one engagement member; and providing a second member disposed in proximity to the adjustment member and having at least one engagement surface, such that the adjustment member is adjustably positionable about the axis of rotation when each engagement member does not engage an engagement surface, and the adjustment member being locked in a selected position about the axis of rotation when at least one engagement member engages an engagement surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Various embodiments are illustrated by way of example and not by limitation in the accompanying figures in which like reference numerals indicate similar elements and in which: 
         FIG. 1  shows a side cross-sectional view of one example of a locking pin turret knob assembly in an engaged, or locked, configuration; 
         FIG. 2  shows a side cross-sectional view of the locking pin turret knob assembly shown in  FIG. 1  in a disengaged, or unlocked, configuration; 
         FIG. 3  shows a side cross-sectional view of one example of a locking spline turret knob assembly in an engaged, or locked, configuration; 
         FIG. 4  shows a side cross-sectional view of the locking spline turret knob assembly shown in  FIG. 3  in a disengaged, or unlocked, configuration; 
         FIG. 5A  shows a side cross-sectional view of one example of a cam-actuated locking turret knob assembly in an engaged, or locked, configuration; 
         FIG. 5B  shows a side cross-sectional view of the cam-actuated locking turret knob assembly of  FIG. 5A  in an unengaged, or unlocked, configuration; 
         FIG. 6A  shows a cross-sectional view of the turret knob shown in  FIG. 5A  taken along line  6 A- 6 A in  FIG. 5A ; 
         FIG. 6B  shows a top view of the turret knob of  FIG. 5A  showing detail of a locking selector thereof; 
         FIG. 6C  shows a side view of the locking selector shown in  FIG. 6B  with other components of the locking turret knob omitted for clarity; 
         FIG. 6D  shows a cross-sectional view of the locking selector shown in  FIG. 6C  taken along line  6 D- 6 D in  FIG. 6C ; 
         FIG. 7A  shows a side cross-sectional view of one example of a locking turret knob assembly in an engaged, or locked, configuration; 
         FIG. 7B  shows a side cross-sectional view of the locking turret knob assembly of  FIG. 7A  in an unengaged, or unlocked, configuration; 
         FIG. 8A  shows a cross-sectional view of one example of a push/pull locking selector that can be used with the locking turret knob shown in  FIG. 7A  with respect to one example of a locking ratchet ring; 
         FIG. 8B  shows a top view of the push/pull locking selector of  FIG. 8A  and one example of a locking turret knob assembly; 
         FIG. 8C  shows a side view of the push/pull locking selector shown in  FIG. 8A  with certain other components of the locking turret knob omitted for clarity; 
         FIG. 8D  shows a cross-sectional view of the push/pull locking selector shown in  FIG. 8C  taken along line  8 D- 8 D in  FIG. 8C ; 
         FIG. 9A  shows a cross-sectional view of the locking turret knob in  FIG. 7A  taken at line  9 A- 9 A in  FIG. 7A , showing detail of a push unlock selector; 
         FIG. 9B  shows a top view of the push unlocking selector shown in  FIG. 9A  and one example of a locking turret knob assembly; 
         FIG. 9C  shows a side view of the push unlocking selector shown in  FIG. 9A  with certain other components of the locking turret knob omitted for clarity; 
         FIG. 9D  shows a cross-sectional view of the push unlocking selector shown in  FIG. 9C  taken along line  9 D- 9 D in  FIG. 9C ; and 
         FIG. 10  shows a flow diagram for making a locking turret knob according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     According to one embodiment, an adjustment knob is provided for an optical setting, such as elevation, windage, parallax, or illuminated reticle power control of an optical-based instrument, such as a telescopic sighting system, a telescope or a microscope, that is mechanically lockable and weather proof, thereby eliminating inadvertent adjustment of an optical setting by accidental physical contact. Accordingly, the user may mechanically unlock the adjustment knob to make a desired adjustment of an optical or power setting. Thus, optical or power settings made by a user are reliably maintained regardless of the environmental conditions or whether the adjustment knob is accidentally touched. 
       FIG. 1  shows a side cross-sectional view of one example of a locking pin turret knob assembly  100  in an engaged, or locked, configuration.  FIG. 2  shows a side cross-sectional view of the locking pin turret knob assembly  100  in a disengaged, or unlocked, configuration 
     Locking pin turret knob assembly  100  includes a turret plate base  101 , an adjustment nut assembly  102  having a lower section  102   a  and an upper section  102   b , a spade screw  103 , a spur ring  104 , a locking ring  105 , a plurality of locking ring splines  106 , an index ring  107 , a plurality of locking pins  108 , a spring member  110  and a turret assembly nut  109 . Turret base plate  101  is fixedly attached to, for example, a telescopic sight or other optical enhancing device (not shown). The lower section of adjustment nut assembly  102   a  fits inside an aperture (not indicated for clarity) that is formed in and passes through turret base plate  101 . In particular, adjustment nut assembly lower section  102   a  and upper section  102   b  are held together by screws  111  in a manner that allows adjustment nut assembly  102  to be fixedly engaged with turret base plate  101  and freely rotate in the aperture formed in turret base plate  101  about an axis  112 . Adjustment nut assembly  102  threadably engages the upper section of spade screw  103 . The lower rectangular section of spade screw  103  passes through a slot in the body of the telescopic sight and mechanically engages an optical adjustor (not shown) of the telescopic sight. 
     Spur ring  104  fixedly fits around adjustment nut assembly upper section  102   b . Locking ring  105 , which includes a plurality of locking ring splines  106 , fixedly fits around turret base plate  101 . Locking ring splines  106  define one or more spline valleys defining engagement surfaces. Index ring  107  fits onto spur ring  104  and around locking ring  105 . A plurality of locking pins  108  are fixedly attached to index ring, engage apertures in spur ring  104  and engage locking ring splines  106  when index ring is fitted onto spur ring  104  and around locking ring  105 . Turret assembly nut  109  threadably engages adjustment nut assembly upper section  102   b  and forms a cavity  113  into which spring member  110  fits. That is, spring member  110  fits into cavity  113  between a top surface  114  of index ring  107  and an inner surface  115  of turret assembly nut  109 . 
     When locking pin turret knob assembly  100  is in a locked configuration, locking pins  108  engage locking ring splines  106  of fixed locking ring  105  so that index ring  107 , spur ring  104 , assembly nut  109 , and adjustment nut assembly  102  cannot be rotated around axis  112  and, consequently, spade screw  103  cannot adjust the corresponding optical adjustment of the telescopic sight. 
       FIG. 2  shows a side cross-sectional view of locking pin turret knob assembly  100  in a disengaged, or unlocked, configuration. By applying a force that moves index ring  107  along axis  112  in a direction  116  away from telescopic sight (i.e., pulling index ring  107  away from the telescopic sight), spring member  110  compresses within cavity  113  and locking pins  108  disengage locking ring splines  106 . While in the unlocked configuration, fixed locking pins  108  of index ring  107  remain in engagement with the apertures of spur ring  104 , and spur ring  104  is fixedly engaged with adjustment nut assembly  102 . Index ring  107  can be rotated around axis  112 , thereby also rotating spur ring  104 , assembly nut  109 , and adjustment nut assembly  102  around spade screw  103  which is fixed from rotation by the lower rectangular portion of the spade screw  103  passing through a slot in the telescopic sight body. Rotation of adjustment nut assembly  102  around spade screw  103  results in a linear movement of spade screw  103  and optical adjustment of the telescopic sight. 
     While  FIGS. 1 and 2  show and have been described by making reference to a plurality of locking pins, it should be understood that only a single locking pin is needed. Additionally, while locking splines  106  have been described, it should be understood that a mechanical member having a plurality of apertures that engage locking pins  108  can alternatively be used. According to another embodiment, locking pins, which are fixedly attached to a structure corresponding to locking ring  105 , could lockably and unlockably engage locking spline structures that are part of the index ring. 
     A marksman may calibrate the locking turret knob illustrated in  FIGS. 1 and 2 , i.e., reorient the orientation of index ring  107  relative to adjustment nut assembly lower section  102   a , as follows: At a predetermined distance, the marksman adjusts an adjuster setting, e.g., elevation, windage or parallax, by unlocking locking pin turret knob  100 , rotating locking turret knob index ring  107 , and releasing index ring  107  to relock the adjuster. Turret assembly nut  109 , detachably coupled (e.g., via screw threads between turret assembly nut  109  and adjustment nut assembly upper section  102   b ) to adjustment nut assembly upper section  102   b , is then uncoupled from adjustment nut assembly upper section  102   b . Index ring  107  may then be pulled by the marksman away from the body of locking pin turret knob  100  so that locking pins  108  disengage from lock ring  105 , thereby allowing the marksman to selectively orient index ring  107  without causing any adjustment of spade screw  103 . Index ring  107  can then be zeroed (by rotating around its axis of rotation) so that, for example, a zero-point mark (not shown) on index ring  107  is aligned with an index mark (not shown) on turret base plate  101 . Turret assembly nut  109  is then re-coupled and tightened to adjustment nut assembly upper section  102   b , which re-engages spring member  110 . Index ring  107  is then biased toward adjustment nut assembly upper section  102   b , engaging locking pins  108  with the locking ring splines  106  of lock ring  105 , thereby re-establishing the locked configuration. 
       FIG. 3  shows a side cross-sectional view of one example of a locking spline turret knob assembly  300  in an engaged, or locked, configuration.  FIG. 4  shows a side cross-sectional view of the locking spline turret knob assembly  300  in a disengaged, or unlocked, configuration. 
     Locking spline turret knob assembly  300  includes a turret base plate  301 , an adjustment nut assembly  302  having a lower section  302   a  and an upper section  302   b , a spade screw  303 , an index ring  304 , and a turret assembly nut  305 . Turret base plate  301  is fixedly attached to, for example, a telescopic sight or other optical enhancing device (not shown). The lower section of adjustment nut assembly  302   a  fits inside an aperture (not indicated for clarity) that is formed in and passes through turret base plate  301 . In particular, adjustment nut assembly lower section  302   a  and upper section  302   b  are held together by screws  306  in a manner that allows adjustment nut assembly  302  to be fixedly engaged with turret base plate  301  and freely rotate in the aperture formed in turret base plate  301  about an axis  307 . Adjustment nut assembly  302  threadably engages the upper section of spade screw  303 . The lower rectangular section of spade screw  303  passes through a slot in the body of the telescopic sight and mechanically engages an optical adjustor (not shown) of the telescopic sight. 
     Index ring  304  fits around adjustment nut assembly upper section  302   b  and includes a plurality of mating splines  308  and a plurality of locking splines  309 . Index ring mating splines  308  engage adjustment nut mating splines  310  of adjustment nut assembly upper section  302   b  as index ring  304  fits around adjustment nut assembly upper section  302   b . Index ring locking splines lockably engage turret base plate locking splines  311  when locking turret knob assembly  300  is in the locked configuration. Turret assembly nut  305  threadably engages adjustment nut assembly upper section  302   b  and forms a cavity  312  into which a spring member  313  fits. That is, spring member  313  fits into cavity  312  between a top surface  314  of index ring  304  and an inner surface  315  of turret assembly nut  305 . 
     When locking pin turret knob assembly  300  is in a locked configuration, index ring locking splines  309  engage turret base plate locking splines  311  so that adjustment nut assembly  302 , index ring  304 , and turret assembly nut  305  cannot be rotated around axis  307  and, consequently, spade screw  303  cannot adjust the corresponding optical adjustment of the telescopic sight. 
       FIG. 4  shows a side cross-sectional view of locking pin turret knob assembly  300  in a disengaged, or unlocked, configuration. By applying a force that moves index ring  304  along axis  307  in a direction  316  away from telescopic sight (i.e., pulling index ring  304  away from the telescopic sight), spring member  313  compresses within cavity  312  and index ring locking splines  309  disengage turret base plate locking splines  311 . While in the unlocked configuration, index ring mating splines  308  continue to engage adjustment nut assembly mating splines  310  of adjustment nut assembly upper section  302   b  and thereby engage adjustment nut assembly  302 . Index ring  304  can be rotated around axis  307 , thereby also rotating turret assembly nut  305 , and adjustment nut assembly  302  around spade screw  303  which is fixed from rotation by the lower rectangular portion of the spade screw  303  passing through a slot in the telescopic sight body. Rotation of adjustment nut assembly  302  around spade screw  303  results in a linear movement of spade screw  303  and optical adjustment of the telescopic sight. 
     When adjustment is completed, the marksman releases index ring  304 , and spring member  313  biases index ring  304  toward turret base plate  301 , thereby returning locking turret knob assembly  300  to the locked configuration. 
     A marksman may calibrate locking turret knob assembly  300  depicted in  FIGS. 3 and 4 , as follows. For a predetermined target distance, the marksman adjusts an adjuster setting, e.g., elevation, windage or parallax, by unlocking locking turret knob assembly  300 , rotating index ring  304  for the desired calibration and then releasing the index ring  304  to relock locking turret knob assembly  300 . Turret assembly nut  305 , which is threadably coupled to adjustment nut assembly upper section  302   b , is unthreaded from adjustment nut assembly upper section  302   b , which releases spring member  313 , thereby allowing index ring mating splines  308  to become disengaged from adjustment nut assembly mating splines  310 . As illustrated in  FIG. 3 , index ring  304  may have a smaller exterior diameter on a bottom portion transitioning via a protruding shoulder  318  to an upper portion with a larger exterior diameter. Index ring  304  can then be pulled by the marksman in the direction indicated by arrow  316 , thus uncoupling index ring mating splines  308  from adjustment nut assembly mating splines  310 . The marksman can then rotate index ring  304  to a desired calibration setting without causing any adjustment of spade screw  303 . That is, index ring  304  can then be zeroed by rotating index ring so that a zero-point mark (not shown) on index ring  304  is aligned with an index mark (not shown) on turret base plate  301 . Turret assembly nut  305  is then rethreaded and tightened onto adjustment nut assembly upper section  302   b , thereby enabling spring member  313  to bias index ring  304  toward adjustment nut assembly upper section  302   b . Index ring mating splines  308  re-engage with adjustment nut assembly mating splines  310  and index ring locking splines  309  re-engage with turret base plate locking splines  311 , thereby re-establishing a locked configuration of locking turret knob assembly  300 , such as shown in  FIG. 3 . 
       FIG. 5A  shows a side cross-sectional view of one example of a cam-actuated locking turret knob assembly  500  in an engaged, or locked, configuration.  FIG. 5B  shows a side cross-sectional view of the cam-actuated locking turret knob assembly of  FIG. 5A  in an unengaged, or unlocked, configuration.  FIGS. 6A   6 D show different views of a locking selector  505  that can be used with the cam-actuated locking turret knob assembly  500 . 
     Cam-actuated locking turret knob assembly  500  includes a turret base plate  501  formed by a lower section  501   a  and an upper section  501   b , an adjustment nut assembly  502 , a spade screw  503 , an index ring  504 , a locking selector  505  and a locking ratchet ring  506 . Turret base plate  501  is fixedly attached to, for example, a telescopic sight or other optical enhancing device (not shown). Adjustment nut assembly  502  fits inside an aperture (not indicated for clarity) that is formed in and passes through turret base plate  501 . Adjustment nut assembly  502  is fixedly engaged with turret base plate  501  and is free to rotate in the aperture formed in turret base plate  501  about an axis  507 . Adjustment nut assembly  502  threadably engages the upper section of spade screw  503 . The lower rectangular section of spade screw  503  passes through a slot in the body of the telescopic sight and mechanically engages an optical adjustor (not shown) of the telescopic sight. Locking ratchet ring  506  is fixedly attached to turret base plate  501 . 
     Index ring  504  fits around turret base plate  501  and is fixedly held to adjustment nut assembly  502  by a set screw  508 . Locking selector  505  fits into an aperture formed in index ring  504  and engages locking ratchet ring  506  with a cam-actuated locking wedge pin  509 . When cam-actuated locking wedge pin  509  is engaged with locking ratchet ring  506 , locking turret knob assembly  500  is in locked position, as shown in  FIG. 5A , thereby rendering index ring  504  unable to be rotated about axis of rotation  507 . A spring-loaded ratchet pin  510  can also be optionally used so that when locking turret knob assembly  500  is unlocked (i.e., cam-actuated locking wedge pin  509  is disengaged from locking ratchet ring  506 ), an adjustment made by rotating locking turret knob assembly  500  will have a tactile feel. In the unlocked configuration, cam-actuated locking wedge pin  509  is disengaged from locking ratchet ring  506 , and index ring  504  and adjustment nut assembly  502  can be rotated around axis  507 , thereby rotating around spade screw  503  which is fixed from rotation by the lower rectangular portion of the spade screw  503  passing through a slot in the telescopic sight body. Rotation of adjustment assembly nut  502  around spade screw  503  results in a linear movement of spade screw  503  and optical adjustment of the telescopic sight. 
       FIGS. 6A-6D  show different views of locking selector  505  that can be used with the cam-actuated locking turret knob assembly  500 . In particular,  FIG. 6A  shows a cross-sectional view of locking selector  505  with respect to locking ratchet ring  506 .  FIG. 6B  shows a top view of locking selector  505  and locking turret knob assembly  500 .  FIG. 6C  shows a side view of locking selector  505 .  FIG. 6D  shows a cross-sectional view of locking selector  505  taken along line  6 D- 6 D in  FIG. 6C . 
     Locking selector  505  includes a selector knob  601 , a selector shaft  602  and a cam surface  603 . When a telescopic sight adjustment is desired, selector knob  601  is grasped and rotated around axis  507  ( FIG. 5A ) from a locked position to an unlocked position. In the unlocked position, cam surface  603  of a selector shaft  602  disengages cam-actuated locking wedge pin  509  from locking ratchet ring  506  and allows index ring  504  to be rotated about axis of rotation  507  ( FIG. 5A ). 
     Upon completion of an adjustment, locking selector  505  is then rotated by the marksman to the locked position. In the locked position, cam surface  603  of locking selector shaft  602  pushes outwardly on cam-actuated locking wedge pin  509  to engage cam-activated locking wedge pin  509  with grooves  511  ( FIGS. 5A and 6A ) of locking ratchet ring  506 . Locking ratchet ring  506  is fixedly coupled to turret base plate  501 , thereby preventing inadvertent adjustment of index ring  504  and spade screw  503 . 
       FIG. 7A  shows a side cross-sectional view of one example of a locking turret knob assembly  700  in an engaged, or locked, configuration.  FIG. 7B  shows a side cross-sectional view of the locking turret knob assembly of  FIG. 7A  in an unengaged, or unlocked, configuration.  FIGS. 9A-9D  show different views of a push-unlocking selector  705  that can be used with the locking turret knob assembly  700 , shown in  FIG. 7A . 
     Locking turret knob assembly  700  includes a turret base plate  701  formed by a lower section  701   a  and an upper section  701   b , an adjustment nut assembly  702 , a spade screw  703 , an index ring  704 , a push-unlocking selector  705  and a locking ratchet ring  706 . Turret base plate  701  is fixedly attached to, for example, a telescopic sight or other optical enhancing device (not shown). Adjustment nut assembly  702  fits inside an aperture (not indicated for clarity) that is formed in and passes through turret base plate  701 . Adjustment nut assembly  702  is fixedly engaged with turret base plate  701  and is free to rotate in the aperture formed in turret base plate  701  about an axis  707 . Adjustment nut assembly  702  threadably engages the upper section of spade screw  703 . The lower rectangular section of spade screw  703  passes through a slot in the body of the telescopic sight and mechanically engages an optical adjustor (not shown) of the telescopic sight. Locking ratchet ring  706  is fixedly attached to turret base plate  701 . 
     Index ring  704  fits around turret base plate  701  and is fixedly held to adjustment nut assembly  702  by a set screw  708 . Index ring  704  also engages locking ratchet ring  706 . Push-unlocking selector  705  fits into an aperture formed in index ring  704  and engages locking ratchet ring  706  with a plunger-actuated locking wedge pin  709 . When push/pull locking wedge pin  709  is engaged with locking ratchet ring  706 , locking turret knob assembly  700  is in locked position, as shown in  FIG. 7A , thereby rendering index ring  704  unable to be rotated about axis of rotation  707 . A spring-loaded wedge pin  710  can also be optionally used so that when locking turret knob assembly  700  is unlocked (i.e., plunger-actuated locking wedge pin  709  is disengaged from locking ratchet  706 ), an adjustment made by rotating locking turret knob assembly  700  will have a tactile feel. In the unlocked configuration, plunger-actuated locking wedge pin  709  is disengaged from locking ratchet ring  706 , and index ring  704  and adjustment nut assembly  702  can be rotated around axis  707  and spade screw  703  which is fixed from rotation by the lower rectangular portion of the spade screw  703  passing through a slot in the telescopic sight body. Rotation of adjustment nut assembly  702  around spade screw  703  results in a linear movement of spade screw  703  and optical adjustment of the telescopic sight. 
       FIGS. 8A-8D  show different views of the push/pull locking selector  805  that can be used with the locking turret knob assembly  700 , shown in  FIG. 7A , as an alternative to push un-locking selector  905 . In particular,  FIG. 8A  shows a cross-sectional view of push/pull locking selector  805  with respect to locking ratchet ring  706 .  FIG. 8B  shows a top view of push/pull locking selector  805  and locking turret knob assembly  700 .  FIG. 8C  shows a side view of push/pull locking selector  805 .  FIG. 8D  shows a cross-sectional view of push/pull locking selector  805  taken along line  8 D- 8 D in  FIG. 8C . 
     Push/pull locking selector  805  includes a selector knob  801 , a selector shaft  802  and a circumferential groove  803 . When a telescopic sight adjustment is desired, selector knob  801  is grasped and pulled in an outwardly direction along axis  707  ( FIG. 7A ) from a locked position to an unlocked position. In the unlocked position, circumferential groove  803  of a selector shaft  802  allows plunger-actuated locking wedge pin  709  to drop into circumferential groove  803 , thereby disengaging locking wedge pin  709  from locking ratchet ring  706  and allowing index ring  704  to be rotated about axis of rotation  707  ( FIG. 7A ). 
     Upon completion of an adjustment, push/pull locking selector  805  is then pushed in an inwardly direction along axis  707  ( FIG. 7A ) from the unlocked position to the locked position. In the locked position, circumferential groove  803  of locking selector shaft  802  moves below locking wedge pin  809  and selector shaft  802  pushes outwardly on plunger-actuated locking wedge pin  709  to engage plunger-activated locking wedge pin  709  with grooves  711  ( FIGS. 7A and 8A ) of locking ratchet ring  706 . Locking ratchet ring  706  is fixedly coupled to turret base plate  701 , thereby preventing inadvertent adjustment of index ring  704  and spade screw  703 . 
       FIGS. 9A-9D  show different views of the push unlocking selector  705  that can be used with a locking turret knob assembly, such as locking turret knob assembly  700  shown in  FIG. 7A . In particular,  FIG. 9A  shows a cross-sectional view of push unlocking selector  705  with respect to a locking ratchet ring  706 .  FIG. 9B  shows a top view of push unlocking selector  705  and the locking turret knob assembly  700 .  FIG. 9C  shows a side view of push unlocking selector  705 .  FIG. 9D  shows a cross-sectional view of push unlocking selector  705  taken along line  9 D- 9 D in  FIG. 9C . 
     Push unlocking selector  705  includes a push selector knob  901 , a selector shaft  902  and a circumferential groove  903 . When a telescopic sight adjustment is desired, selector knob  901  is pushed inwardly from a locked position to an unlocked position. In the unlocked position, circumferential groove  903  of a selector shaft  902  moves inward and allows plunger-actuated locking wedge pin  709  to disengage from locking ratchet ring  706  and allows an index ring (not shown) to be rotated about an axis of rotation (not shown). 
     Upon completion of an adjustment, selector knob  901  is then released from the unlocked position to the locked position. In the locked position selector shaft  902  moves outward thereby moving circumferential groove  903  of selector shaft  902  to move above wedge pin  709 . The lower section of selector shaft  902  pushes outwardly on locking wedge pin  709  to engage plunger-activated locking wedge pin  709  with grooves  711  ( FIGS. 7A and 9A ) of locking ratchet ring  706 . Locking ratchet ring  706  is fixedly coupled to a turret base plate (not shown), thereby preventing inadvertent adjustment of the index ring and a spade screw. 
       FIG. 10  shows a flow diagram  1000  for making a locking turret knob according to one embodiment. An adjustment member is detachably coupled at  1001  to an adjuster, such that the axis of rotation of the adjustment member coincides with the axis of rotation of the adjuster. At  1002 , an adjustment member locking mechanism is then coupled to the base for preventing unintended rotation of the adjustment member. With the locking turret knob in the normally locked state, a marksman can unlock the index ring in order to perform an adjustment. When the adjustment member is unlocked, rotating the adjustment member produces an adjustment of the adjuster. At  1003 , a spring member, such as a spring, may be provided for producing a biasing force on the adjustment member, thereby rendering the adjustment member normally coupled to the base, i.e., locked. Operator-supplied force counteracting the biasing force uncouples the adjustment member from the base, enabling the operator to effect an adjustment of the adjuster via, e.g., rotating the index ring. 
     It should be understood that the locking turret knob assemblies described herein can be used as adjustment knobs for a telescopic sight or any other optical-based instrument having adjustment knobs, for example an optical enhancing device such as a lens or microscope, telescope, etc. 
     Although the foregoing description includes some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be made to the details of the above-described embodiments that are within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.