Abstract:
A compact adjustment knob for an optical, mechanical, or electronic device includes a spindle supported on the device for rotation about an axis to control a setting of the device, and a releasable automatically locking lock mechanism supported on the spindle for rotation therewith. The lock mechanism includes at least one manually depressible button accessible on an outer surface of the adjustment knob and connected to an actuator shaft that extends inwardly through a drive hole in an outer side wall of the spindle so that a force manually applied to the button is transmitted by the actuator shaft to drive the lock mechanism and rotate the spindle. The lock mechanism may include a lock sleeve that is biased to a normally locked position and driven along the axis by the actuator shaft when the button is depressed.

Description:
RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/752,418, filed Jan. 14, 2013, which is incorporated herein by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The field of the present disclosure relates to automatically locking (auto-locking) rotatable adjustment knobs used to adjust a setting of a device such as a riflescope or other optical device, an electronic device, or a mechanical device. 
       BACKGROUND 
       [0003]    Rotatable adjustment knobs or control knobs are commonly utilized to adjust settings of optical, mechanical, and electrical devices. Riflescopes and similar weapon aiming devices commonly include a pair of orthogonally mounted rotatable adjustment knobs, also known as turret knobs or simply turrets, which are used for adjusting elevation and windage settings affecting the respective vertical and horizontal aim of the riflescope, and thus of the weapon to which the riflescope is attached. Rotating adjustment knobs are also commonly used on riflescopes and other optical devices for adjusting focus, reticle illumination intensity, display settings, display illumination, and other settings of the device. Rotating adjustment knobs are also used on various other optical, electronic, and mechanical devices, such as spotting scopes, binoculars, microscopes, stereos and radios, appliances, automobile controls, and measurement instruments, for example. 
         [0004]    In some applications, it is advantageous for an adjustment knob to automatically lock in place to prevent inadvertent adjustment. U.S. Pat. No. 8,006,429, issued Aug. 30, 2011, describes various locking turret knobs for riflescopes, some of which are normally locked, but may be unlocked by applying a releasing force to the knob or a component thereof, then rotating the knob to make an adjustment. In some embodiments described in the &#39;429 patent, when the manual force is removed a spring or other biasing device of the knob automatically returns the locking mechanism to its normally locked state, preventing inadvertent rotation of the adjustment knob, for example during transit or other handling. 
         [0005]    Patent Application Publication No. US 2011/0100152 A1 describes an auto-locking adjustment mechanism including a pair of buttons on opposite sides that are manually depressed with a pinching action to release the locking mechanism and allow the knob to be rotated for adjustment of a setting of a riflescope or other device. When force is released from the buttons, the device automatically locks. Hence, the adjustment mechanism is sometimes referred to as a pinch-and-turn adjustment knob or a pinch/turn knob. The buttons are carried by a knob body that is installed over and frictionally secured to a threaded spindle of the device by a pair of set screws. The knob carries an indicator ring marked to provide a visual indication of the rotational position of the knob relative to the riflescope. The zero position of the knob can be adjusted relative to the spindle by loosening the set screws, rotating the knob until a zero marking on the indicator ring is aligned as desired relative to the riflescope main tube, then re-tightening the set screws. Each of the buttons carries an actuator shaft that extends radially through a bore in the side of the knob body and operatively engages a linkage within the mechanism that is driven in an axial direction when the buttons are depressed to release the locking mechanism, allowing the knob body and spindle to be rotated together to drive a threaded adjustment screw plunger or another type of adjustment device. 
         [0006]    The present inventor has recognized a need for an improved auto-locking pinch/turn adjustment knob. 
       SUMMARY 
       [0007]    An adjustment knob for adjusting an optical, mechanical, or electronic device, includes a spindle supported on the device for rotation about an axis and a releasable lock mechanism supported on the spindle for rotation therewith. The spindle is operatively associated with an adjustment mechanism that controls a setting of the device. The lock mechanism includes a button that is manually depressible in a generally radial direction from a radially outward locked position at which the lock mechanism constrains the spindle to prevent it from rotating relative to the device, to a radially inward unlocked position that releases the lock mechanism and allows the spindle to be rotated. The lock mechanism also includes an actuator shaft connected to the button and extending radially inward through a drive hole in an outer side wall of the spindle. A force applied to the button drives the lock mechanism and is transmitted to the spindle via the actuator shafts to rotate the spindle. A hermetic seal may be provided between the actuator shaft and the drive hole, which also provides a sliding interface therebetween. The spindle and its outer side wall, including the drive hole, are preferably formed in a monolithic structure for rigidity and sealing purposes, among others. Accordingly, the spindle may be driven for rotation by forces transmitted directly from the button to the spindle primarily via engagement of the actuator shaft in the drive hole. 
         [0008]    The lock mechanism may include a lock sleeve having a tapered surface that is contacted by the actuator shaft and thereby driven along the axis by the actuator shaft when the button is depressed. The lock sleeve may be positioned in an annular groove of the spindle and is preferably biased in the axial direction toward the locked position by a spring that is operably interposed between the lock sleeve and the spindle and concentric with the axis. The lock sleeve is driven in opposition to the spring force toward the unlocked position by depressing the button. The spring preferably has sufficient biasing force to return the lock sleeve and the button to the locked position when external force is released from the button. The lock mechanism may further include a lock pin carried by the spindle, which is contacted by the lock sleeve and driven radially outward by movement of the lock sleeve and into engagement with a catch when the lock sleeve is in the locked position. 
         [0009]    The adjustment mechanism may include a threaded adjustment plunger such as an adjustment screw threaded into the spindle and constrained to prevent it from rotating about the axis, or may include a different kind of adjustment mechanism, such as an orbital pin, crown gear arrangement, spiral cam mechanism, etc. The lock sleeve may encircle the threaded adjustment plunger or screw. 
         [0010]    The adjustment knob may further comprise a revolution indicator pin attached to the adjustment screw for movement therewith along the axis and visible from outside of the adjustment knob to provide a visual indication of the number of revolutions that the spindle is turned relative to an initial zero position. 
         [0011]    The adjustment knob may also include a second lock-release button and second actuator shaft supported on the outer side wall of the spindle opposite the button so that the button and the second button may be pinched toward each other by a user to unlock the lock mechanism. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is an isometric cross sectional view of an auto-locking adjustment knob shown installed on a riflescope illustrated in partial cross section; 
           [0013]      FIG. 2  is an exploded assembly view showing the adjustment knob and a riflescope housing of  FIG. 1 ; 
           [0014]      FIG. 3  is an enlarged isometric view of a spindle of the adjustment knob of  FIG. 1 ; 
           [0015]      FIG. 4  is an isometric cross sectional view of the spindle of  FIG. 3 ; 
           [0016]      FIG. 5  is top view of the spindle of  FIG. 3 ; 
           [0017]      FIG. 6  is a side view of the spindle of  FIGS. 3 and 5 ; 
           [0018]      FIG. 7  is a cross sectional view taken along lines  7 - 7  of  FIG. 6 ; 
           [0019]      FIG. 8  is a cross sectional view taken along lines  8 - 8  of  FIG. 7 ; and 
           [0020]      FIG. 9  is an auxiliary view of the adjustment knob of  FIG. 1 , illustrating a process for manually re-positioning or re-zeroing an indicator ring of the adjustment knob. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0021]      FIG. 1 . is an isometric cross sectional view of an auto-locking pinch/turn adjustment knob  10  in accordance with a presently preferred embodiment, illustrated as an elevation control knob mounted on a housing (main tube  12 ) of a riflescope  14 . Riflescope  14  is merely exemplary of a type of optical aiming device with which adjustment knob  10  may be utilized. Other devices with which adjustment knob  10  may be used are noted elsewhere herein. 
         [0022]    With reference to  FIG. 1 , adjustment knob  10  includes a threaded adjustment plunger in the form of an adjustment screw  20  extending into an interior  22  of riflescope  14  via a slot  24  (best shown in  FIG. 2  along with a similar second slot  24   a  for a windage adjustment screw). Slot  24  is formed in a floor  26  of a turret seat  28  ( FIG. 2 ) that is formed on a lateral outer surface  29  of main tube  12 . Flats  32 ,  34  on the sides of an inner end of adjustment screw  20  prevent adjustment screw  20  from rotating relative to main tube  12 . Turret seat  28  includes a threaded mounting boss  30  into which a threaded adapter ring  36  is fitted. Adjustment screw  20  is threaded into a threaded bore  38  of a spindle  40  that is retained in turret seat  28  for rotation about an axis  44  of adjustment knob  10  as further described below. When spindle  40  is rotated, the rotatably constrained adjustment screw  20  is driven along axis  44  to adjust a setting of riflescope  14 , for example by bearing against and moving an erector lens holder tube (not shown) that may be disposed within and pivotably mounted to main tube  12 , and spring-biased to press against the inner end of adjustment screw  20 . In an alternative embodiment (not illustrated), instead of adjustment screw  20 , the threaded adjustment plunger may comprise an internally threaded post or standoff having a threaded end portion for mounting to an externally threaded portion of a spindle. 
         [0023]    A retainer nut  50  having an inwardly extending lip  52  is threaded onto an axially outer end  56  of adapter ring  36  that extends beyond mounting boss  30  to retain spindle  40  in turret seat  28 . A flange  58  of spindle  40  is captured between lip  52  and the axially outer end  56  of adapter ring  36 . Retainer nut  50  is sized to provide clearance around flange  58 , allowing smooth rotation of spindle  40 . An o-ring  70  or sliding gasket made of a resilient material is positioned in a groove or step  74  formed in outer end  56  of adapter ring  36  and is sized to project beyond outer end  56  to provide a bearing surface for spindle  40 , while also providing a hermetic seal between spindle  40  and adapter ring  36 . A second sealing gasket or o-ring  78  is positioned between adapter ring  36  and turret seat  28 . In the embodiment illustrated, adapter ring  36  is provided on a standard mounting boss  30  design (which may fit many different styles of adjustment knobs) to retrofit the mounting boss  30  for the particular mounting requirements of adjustment knob  20 . In other embodiments (not shown), adapter ring  36  may be omitted, and retainer nut  50  may be threaded directly onto main tube  12 . 
         [0024]    Although the preferred embodiment is described herein as an adjustment screw device for a riflescope, embodiments of the pinch/turn adjustment knob described herein may be utilized with adjustment mechanisms other than adjustment screws, such as other mechanical devices, electrical controls, and other mechanisms. For example, instead of a threaded adjustment plunger, the adjustment mechanism may comprise an eccentric pin or spiral cam mechanism of the kind described in U.S. Pat. No. 6,351,907, issued Mar. 5, 2002, a crown gear mechanism, taut-band mechanism, or other mechanical device. Alternatively, the adjustment knob may rotate an electrical control comprising a rheostat or an arrangement of electrical contact pads that are selectively brought into contact with electrical contacts depending on the position of the control knob. 
         [0025]    Turning back to the preferred embodiment of  FIG. 1 , a detent ring  90  is press-fit or cemented to an inner face  94  ( FIG. 2 ) of adapter ring  36  and bears a series of catch structures, for example evenly spaced alternating axially extending ridges and grooves (detent grooves  96 ), formed along an inner surface of detent ring  90 . In an alternative embodiment (not illustrated), detent ring  90  may be omitted in favor of detent grooves  96  or other catch structures formed directly in the surface of adapter ring  36  or, if adapter ring  36  is omitted as suggested above, in an inner circumferential surface of mounting boss  30 . A lock pin  110  is slidably mounted in a radial bore  114  formed in spindle  40  near its base  116 .  FIGS. 3 and 4  are respective isometric and cross sectional views of spindle  40  showing detail of bore  114  and other aspects of spindle  40 .  FIGS. 5-8  illustrate additional views of spindle  40 . With reference to  FIGS. 1 ,  3 , and  4 - 8 , bore  114  extends through an outer wall  120  of spindle  40  into an annular groove  126  ( FIG. 4 ) that is coaxially aligned with spindle  40  (on axis  44 ). Spindle  40  and its outer side wall  120 , including bore  114 , annular groove  126 , drive holes  194 ,  196 , and other features illustrated in  FIGS. 5-8 , are preferably formed in a monolithic structure to provide rigidity or improved sealing, or for other reasons. A coil spring  130  encircling a neck portion  132  of lock pin  110  is captured in a pocket  134  leading to bore  114 , and is compressed to bear against a head  138  of lock pin  110  and a bottom of the pocket  134  to urge lock pin  110  radially outward against detent ring  90  and into detent grooves  96 . 
         [0026]      FIG. 2  shows how the outer end  142  of head  138  is wedge-shaped to allow it to ride over the ridges and grooves  96  ( FIG. 1 ) of detent ring  90  during rotation of adjustment knob  10  to provide tactile and/or auditory feedback of clicks indicating a predetermined amount of adjustment. In one embodiment, detent ring  90  includes one hundred ( 100 ) regularly spaced detent grooves  96  circumscribing detent ring  90 , and the pitch of adjustment screw  20  is selected so that each click represents approximately 0.1 milliradian (mils) of elevation or windage adjustment. In other embodiments a greater or lesser number of detent grooves  96  may be provided and the pitch of adjustment screw  20  may be different. 
         [0027]    With reference again to  FIG. 1 , an annular lock sleeve  150  surrounds adjustment screw  20  and is retained in annular groove  126  of spindle  40  in operative engagement with lock pin  110 . A lock spring  160  captured between an inner lip  164  of lock sleeve  150  and spindle  40  is operably interposed therebetween to urge spindle  40  axially outward along axis  44 . A pair of release buttons  174 ,  176  are supported adjacent opposite sides of spindle  40  where they are exposed and can be manipulated and operated from outside adjustment knob  10  by grasping or pressing them via a user&#39;s fingers. Release buttons  174 ,  176  are retained on spindle  40  by a cap  180  that is threadably secured to spindle  40  over an axially outer end  182  thereof. First and second actuator shafts  184 ,  186  are mounted to and extend radially inward from buttons  174 ,  176  through drive holes  194 ,  196  ( FIG. 3 ) formed in outer wall  120  of spindle  40 . A skirt portion  188  of cap  180  extends axially from a peripheral edge of cap  180  to retain buttons  174 ,  176 . Actuator shafts  184 ,  186  are each fitted with o-rings  190 , providing a hermetic seal and sliding interface between actuator shafts  184 ,  186  and drive holes  194 ,  196 . Actuator shafts  184 ,  186  have radiused tips that engage a tapered shoulder surface  198  of lock sleeve  150  when release buttons  174 ,  176  are depressed. First release button  174  and actuator shaft  184  are shown in  FIG. 1  in their depressed (unlocked) position, whereat the inner end of actuator shaft  184  bears against shoulder surface  198  to drive lock sleeve  150  axially inward to its unlocked position in opposition to the biasing force of lock spring  160 . In the unlocked position, a foot portion  200  of lock sleeve  150  is moved axially inward and a channel  202  on an outer surface of lock sleeve  150  between foot portion  200  and shoulder surface  198  is aligned with a heel  208  of lock pin  110 , providing clearance that allows lock pin  110  to reciprocate within bore  114  for providing tactile and audible feedback to the user as adjustment knob  10  is turned. 
         [0028]    In an alternative embodiment (not illustrated), the lock sleeve  150  may instead be biased in an inward direction, and configured and interfaced with the actuator shafts  184 ,  186  and lock pin  110  so that when the release buttons are depressed the actuator shafts drive the lock sleeve in an axially outward direction to unlock the adjustment knob. 
         [0029]    Second release button  176  and actuator shaft  186  are shown in  FIG. 1  in the locked (undepressed) position (although the lock sleeve  150  is shown in the unlocked position by virtue of the first release button  174  being depressed). When manual pinching force is removed from both release buttons  174  and  176  they return to the locked position by virtue of the biasing force provided by lock spring  160  driving lock sleeve  150  axially outward. In the locked condition, the foot portion  200  of lock sleeve  150  presses against heel  208  of lock pin  110  to drive lock pin  110  radially outward and securely seat outer end  142  in one of the detent grooves  96 , which locks adjustment knob  10  to prevent it from being inadvertently rotated about axis  44 . 
         [0030]    O-rings  74 ,  78 ,  190 , and additional seals or o-rings  220 ,  222 , are provided at interfaces between parts of adjustment knob  10  to hermetically seal main tube  12  and retain a dry gas charge therein to prevent weather-induced condensation on internal optical elements (not shown) of riflescope  14 . A further o-ring  224  is provided along an outer surface of flange  58  of spindle  40  to help center spindle  40  on axis  44 , and to prevent dust and grit from migrating into the sliding bearing between flange  58 , retainer nut  50 , and adapter ring  36 . 
         [0031]    The design of adjustment knob  10  is greatly simplified relative to the device disclosed in US 2011/0100152, reducing component cost and assembly expense, and further providing certain advantages. The shape of lock sleeve  150  enables it to extend into annular groove  126  in spindle  40  and directly engage lock pin  110 , thereby eliminating a lock pin linkage of prior designs. The shape of lock sleeve  150  also enables the use of concentric lock spring  160 , which provides a centered biasing force that may be sufficient for returning release buttons  174 ,  176  to the locked position, thereby eliminating the need for separate button return springs of prior designs. Alternatively, a second return spring or set of springs (not illustrated) may be provided to act directly on buttons  174 ,  176  and/or actuator shafts  184 . For example, a leaf spring or spring loop may be interposed between the tips of actuator shafts  184 ,  186  and extend around a stem  290  of cap  180  where there is space for the leaf spring or loop spring to flex when buttons  174 ,  176  are depressed. 
         [0032]    Extending the actuator shafts  184 ,  186  through drive holes  194 ,  196  in spindle  40  eliminates the need for a separate button-carrying knob body of prior designs and the frictional connection between the button-carrying knob body and the spindle provided by a set screw of prior designs. Instead, the actuator shafts  184 ,  186  and buttons  174 ,  176  are carried by drive holes  194 ,  196  of spindle  40 , and directly drive spindle  40  for rotation about axis  44  without the need for a frictional connection that the inventors have found prone to slippage. Several of the above-described differences also cooperate to provide an adjustment knob  10  having an overall height above floor  26  of turret seat  28  (or above the lateral outer surface  29  of main tube  12 ) that is approximately half that of prior designs. In some embodiments, adjustment knob  10  has an overall height H above floor  26  in the range of approximately 0.55 inch to approximately 0.7 inch (approximately 14 to 18 mm). In other embodiments, adjustment knob  10  may have a height H in the range of 0.5 to 0.8 inch (12.7 to 20.3 mm), or in the range of 0.5 to 0.9 inch (12.7 to 22.9 mm), or in the range of 0.5 to 1.0 inch (12.7 to 25.4 mm). This low-profile design is advantageous for use with riflescopes, as it avoids obscuring the shooter&#39;s view past the outside of the riflescope and may facilitate the use of auxiliary aiming devices such as reflex sights that may be mounted alongside or closely above riflescope  14 . 
         [0033]    With reference to  FIGS. 1 ,  2 , and  9 , an indicator ring  250  bearing a scale  254  or other indicia marked along an outer circumferential surface thereof is installed around adjustment knob  10  and over retainer nut  50 . Indicator ring  250  includes a set of splines formed along an inner shoulder opening  258  ( FIG. 2 ) of indicator ring  250 . The splines of indicator ring  250  are sized to mesh with splines  270  ( FIG. 3 ) formed around outer wall  120  of spindle  40  adjacent and axially outward of flange  58  so that indicator ring  250  rotates with spindle  40  relative to main tube  12 . A fiduciary mark (not shown) on the outside of mounting boss  30  is visually referenced by a user to read the rotational position of adjustment knob  10  from scale  254 . 
         [0034]    Due to elimination of the adjustable frictional connection of prior designs between an outer knob body and a spindle, a different mode of re-zeroing adjustment knob  10  is provided in the present embodiment. The rotational position of indicator ring  250  is adjustable relative to spindle  40  for re-zeroing the indicator ring  250 , for example after sighting-in riflescope  14 . With particular reference to  FIG. 9 , to adjust the position of indicator ring  250 , actuator buttons  274 ,  276  (which serve as a latch for retaining indicator ring  250 ) are depressed with one hand and indicator ring  250  is pulled axially outward around buttons  274 ,  276  with the other hand, then indicator ring  250  is rotated relative to spindle  40  and replaced axially onto splines  270 . Indicator ring  250  may also be completely removed from adjustment knob  10  in the same two-handed manner by depressing buttons  274 ,  276  and sliding indicator ring  250  over buttons  274 ,  276 , and subsequently replaced with an indicator ring having a different scale, such as a scale calibrated for a particular type of weapon and/or ammunition. Further details of adjustable replaceable indicator rings similar to ring  250  are provided in U.S. patent application Ser. No. 13/683,985, filed Nov. 21, 2012, which is incorporated herein by reference. 
         [0035]    Turning again to  FIG. 1 , cap  180  includes a tubular central stem  290  extending axially inwardly around an outer end  296  of adjustment screw  20 . O-ring  222  is fitted in a circumferential groove around outer end  296  of screw  20  to achieve hermetic seal therebetween. O-ring  222  facilitates sliding movement of screw  20  relative to cap  180  as adjustment knob  10  is adjusted. An optional threaded revolution indicator pin  300  is threaded into a threaded bore  310  in the outer end of adjustment screw  20 . Revolution indicator pin  300  rides with adjustment screw  20  as adjustment knob  10  is adjusted so that a head  316  of revolution indicator pin  300  projects outwardly beyond an outer major surface  320  of cap  180  as adjustment screw  20  is adjusted. A pair of circumscribed indicator grooves  324 ,  326  or markings on head  316  indicate the number of revolutions that adjustment knob  10  has been turned. For example, when adjustment knob  10  has been turned a full revolution to achieve 10 milliradians of angular aiming adjustment the outermost groove  324  is visible slightly above with the outer major surface  320  of cap  180 , as illustrated in  FIG. 9 , and when adjustment knob  10  has been rotated two revolutions to achieve an angular aiming adjustment of 20 milliradians the second groove  326  is visible slightly above outer major surface  320 . Thus, visibility of none, one, or both of grooves  324 ,  236  indicates the number of revolutions of adjustment knob  10 . In other embodiments (not illustrated), the revolution indicator pin  300  is omitted and the top of cap  180  is solid. 
         [0036]    A slot  330  in the head of revolution indicator pin  300  is sized so that a tail of a cartridge or a small flathead screwdriver can be used to adjust a zero stop position by tightening revolution indicator pin  300  until head  316  is snugly seated in a counterbore  334  ( FIG. 2 ) of cap  180  in the zero position shown in  FIG. 1 . The zero stop position enables adjustment knob  10  to be quickly returned to the zero position after an adjustment, without looking at revolution indicator pin  300 . Also, during sighting-in of a weapon and riflescope  14 , revolution indicator pin  300  may be loosened or removed to allow unrestricted travel of adjustment screw  20 . After the weapon and riflescope  14  have been sighted in, revolution indicator pin  300  is replaced and tightened to set the zero stop point of adjustment knob  10 . After subsequent adjustments of adjustment knob  10  (e.g., elevation adjustment for longer range shots), adjustment knob  10  can be quickly returned to the zero stop position merely by rotating adjustment knob  10  in the opposite direction until it stops against head  316  of revolution indicator pin  300 . 
         [0037]    Completely removing revolution indicator pin  300  reveals a tool-receiving drive socket, such as a hex socket  340  within stem  290  that receives a tool (such as a hex key, not illustrated) for removing cap  180  and disassembling adjustment knob  10  for maintenance or replacement. 
         [0038]    Except for o-rings  70 ,  78 ,  190 ,  220 ,  222 , and  224  and springs  130  and  160 , all components of adjustment knob  10  may be machined from solid aluminum, steel, or another metal. In some embodiments, lock sleeve  150 , actuator shafts  184 ,  186 , lock pin  110 , and certain other friction and wear components may be polished and/or coated with a wear-resistant hard coating or made from a low-friction material for enhancing durability and reliability. Alternatively, some components may be made of plastic or another low-cost or low-friction material, albeit usually resulting in a less durable device. 
         [0039]    It will be obvious to those having skill in the art that many changes may be made to the details of the above-described embodiments without departing from the underlying principles of the invention. The scope of the present invention should, therefore, be determined only by the following claims.