Abstract:
A firearm accessory mount includes a main part with a rail receiving portion extending in a first direction that can receive a firearm mount rail, and includes a holding part with a rail engaging portion. The holding part is movable relative to the main part so that the rail engaging portion moves approximately parallel to a second direction forming an angle to the first direction. An adjusting portion positionally adjusts the rail engaging portion with respect to the main part, approximately parallel to a third direction transverse to each of the first and second directions. A manually operable member is operatively coupled to the holding part so that the holding part is moved approximately parallel to the second direction in response to movement of the member.

Description:
FIELD OF THE INVENTION 
   This invention relates in general to accessories for firearms and, more particularly, to techniques for removably mounting a firearm accessory on a firearm. 
   BACKGROUND 
   In some situations, it is desirable to be able to mount an accessory on a firearm. The most common type of accessory is a sight or scope that can increase the accuracy with which a person can aim the firearm. The person views an intended target through the sight or scope in association with a reticle, often with a degree of magnification. 
   Accessories such as firearm sights are usually aftermarket devices that need to be mounted on the firearm after the manufacturer has made and shipped the firearm. Usually, it is the end user who selects and mounts the accessory on the firearm. In some circumstances, a person may want to be able to quickly switch from one accessory to another, for example from one sight to another sight. Therefore, it has become relatively standard for firearm manufacturers to provide an accessory mounting rail on the firearm. The rail is usually provided on the “receiver” of the firearm, or in other words the part of the firearm that carries the bolt. 
   One very common type of mounting rail is known in the industry as a Picatinny rail. Although the Picatinny rail is effectively an industry standard, the industry specification for the Picatinny rail is not particularly precise. For example, it includes a drawing that has some dimensional errors. As a result, Picatinny rails vary somewhat in dimension from manufacturer to manufacturer, and even among different versions of a Picatinny rail made by the same manufacturer. 
   Many firearm accessories such as sights and scopes are provided with mounting arrangements that are designed to cooperate with a Picatinny rail. While these existing mounting arrangements have been generally adequate for their intended purposes, they have not been satisfactory in all respects. 
   For example, some have one or more knobs that each need to be rotated through several 360° revolutions in order to couple or decouple the mounting arrangement to the rail. Devices of this type cannot be mounted to and dismounted from a rail as rapidly as is sometimes desirable. 
   A further consideration is that, due to the dimensional variations among different Picatinny rails, some mounting arrangements will tightly and securely grip some Picatinny rails, but cannot tightly and securely grip other Picatinny rails. In some cases, if a particular Picatinny rail happens to be on the large side, a user may have to press hard on a lever or other actuating member in order to get the clamping mechanism to properly lock onto the rail. The force exerted on the lever can sometimes cause the lever to break. 
   Still other mounting arrangements have a cam or other clamping part that, as it moves into a clamping position, rubs along the side of the Picatinny rail, thereby abrading the side of the rail. This can mar and/or burnish the rail, which in turn can reduce the ability of the rail to be tightly and securely gripped by the mounting arrangement. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the present invention will be realized from the detailed description that follows, taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a diagrammatic bottom view of an apparatus that is a firearm accessory mount embodying aspects of the invention. 
       FIG. 2  is a diagrammatic sectional view taken along the section line  2 - 2  in  FIG. 1 . 
       FIG. 3  is a diagrammatic perspective bottom view of a main part that is a component of the accessory mount of  FIG. 1 . 
       FIG. 4  is a diagrammatic perspective bottom view of a bushing that is a further component of the accessory mount of  FIG. 1 . 
       FIG. 5  is a diagrammatic perspective bottom view of a shaft that is yet another component of the accessory mount of  FIG. 1 . 
       FIG. 6  is a diagrammatic perspective top view of a locking lever that is still another component of the accessory mount of  FIG. 1 . 
       FIG. 7  is a diagrammatic perspective top view of a locking slide that is a further component of the accessory mount of  FIG. 1 . 
       FIG. 8  is a diagrammatic perspective bottom view of the locking slide of  FIG. 7 . 
       FIG. 9  is a diagrammatic top view showing the locking slide of  FIGS. 7-8  slidably supported on the locking lever of  FIG. 6 . 
       FIG. 10  is a diagrammatic sectional view taken along the section line  10 - 10  in  FIG. 9 . 
   

   DETAILED DESCRIPTION 
     FIG. 1  is a diagrammatic bottom view of an apparatus that is a firearm accessory mount  10  embodying aspects of the present invention.  FIG. 2  is a diagrammatic sectional view taken along the section line  2 - 2  in  FIG. 1 . In the following discussion, words such as up, down, top, bottom, horizontal and vertical are used in relation to the normal operation orientation of the accessory mount  10 , but it will be understood that this is for convenience and is not to be considered limiting. The accessory mount  10  is used to removably mount a not-illustrated accessory on the mounting rail  12  ( FIG. 2 ) of a not-illustrated firearm, such as a rifle. The most common type of accessory is an aftermarket sight or scope, or in other words a device that is used to increase the accuracy with which the firearm can be aimed at a target. However, the accessory mount  10  can be used not only for a sight or scope, but also for any of a variety of other accessories. 
   The rail  12  in  FIG. 2  is a conventional type of rail that is commonly known in the art as a “Picatinny” rail. Although the Picatinny rail is effectively an industry standard, the industry specification for the Picatinny rail is not particularly precise. For example, it includes a drawing that has some dimensional errors. As a result, Picatinny rails vary somewhat in dimension from manufacturer to manufacturer, and even among different versions of a Picatinny rail made by the same manufacturer. With reference to  FIG. 2 , the rail  12  is elongate in a horizontal direction perpendicular to the plane of  FIG. 2 . This direction is indicated diagrammatically in  FIG. 1  by a broken line  16 . The rail  12  has opposite side edges  13  and  14  that extend parallel to each other and to the direction  16 . The side edges  13  and  14  each taper outwardly, and would end in a sharp corner or point, except that there is a chamfer or bevel surface extending along the outer end. 
   The accessory mount  10  has a main part or base  21 . The base  21  is also sometimes referred to as a cover.  FIG. 3  is a diagrammatic perspective bottom view of the main part  21 . In the disclosed embodiment, the main part  21  is made of aluminum or an aluminum alloy, but it could alternatively be made of any other suitable material. A groove-like channel  23  is provided in the bottom of the main part  21 . The channel  23  extends parallel to the direction  16 , and is open at each end. The channel  23  has a flat inner surface  24 , and two sides  27  and  28 . The side  27  has two surfaces that intersect approximately at a right angle, to define a V-shaped groove. As shown in  FIG. 2 , this groove can slidably receive the outwardly tapered edge  13  of the rail  12 . The other side of the channel  23  is defined by a surface  28  that is inclined at an angle of approximately 45° with respect to the inner surface  24 , and that can slidably engage a surface on the edge  14  of the rail  12 . Thus, the rail  12  can be received within the channel  23 , and the accessory mount  10  is capable of sliding movement along the rail  12  in directions parallel to the line  16 , until the accessory mount is securely clamped to the rail in a manner described later. With reference to  FIGS. 1 and 3 , a projection  33  is disposed within the channel  23 , and extends downwardly from the inner surface  24 . When the accessory mount  10  is securely clamped to the Picatinny rail  12 , the projection  33  can engage any of several not-illustrated recesses provided at spaced locations along the length of the rail  12 , in order to prevent sliding movement of the base  21  on the rail  12 . 
   The base  21  has a downwardly-facing flat surface  38  that extends horizontally outwardly from the lower edge of the side  28  of the channel  23 . A short distance outwardly from the side  28 , the base  21  has a threaded cylindrical opening  36  that extends vertically upwardly from the surface  38 . The opening  36  does not extend all the way through the base  21 . The base  21  also has in the surface  38  a shallow annular groove  37  that concentrically encircles the opening  36 , a short distance radially outwardly from the opening  36 . 
   At a location spaced further outwardly from the channel  23 , the base  21  has a further cylindrical opening  40  that extends vertically upwardly from the surface  38 , and that opens through the top of the base. The opening  40  has a lower portion  41  and an upper portion  42 . The lower portion  41  has a larger diameter than the upper portion  42 , thereby defining a downwardly-facing annular shoulder  43  within the opening  40 . The base  21  also has a tab  47  that projects horizontally outwardly from a location near the openings  36  and  40 . Two spaced and parallel ribs or guides  48  and  49  are disposed on opposite sides of and project downwardly from the surface  38 . The guides  48  and  49  each extend parallel to a horizontal direction  52  that is perpendicular to the horizontal direction  16 . 
   With reference to  FIG. 2 , the accessory mount  10  includes a sleevelike cylindrical bushing  61 .  FIG. 4  is a diagrammatic perspective bottom view of the bushing  61 . The bushing  61  has a sleevelike lower portion  62  and a sleevelike upper portion  63 . The lower portion  62  has inside and outside diameters that are respectively larger than the inside and outside diameters of the upper portion  63 . Thus, the bushing  61  has a downwardly facing annular shoulder  64  in its interior, and upwardly facing annular shoulder  65  on its exterior. In the disclosed embodiment, the bushing  61  is made of steel, but it could alternatively be made of any other suitable material. The bushing  61  fits snugly with a force fit in the opening  40  ( FIGS. 2 and 3 ) of the base  21 . 
   With reference to  FIG. 2 , the accessory mount  10  includes a shaft  71  that can rotate about a vertical axis  72 .  FIG. 5  is a diagrammatic perspective bottom view of the shaft  71 . The shaft  71  has a lower cylindrical portion  76 , a middle cylindrical portion  77 , and an upper cylindrical portion  78 , all of which are concentric to the axis  72 . The middle portion  77  has a larger diameter than the upper portion  78 , and the lower portion  76  has a larger diameter than the middle portion  77 . The upper portion  78  has external threads. The upper part of the middle portion  77  has flat surfaces on opposite sides thereof, one of which is visible at  81 . Adjacent each flat surface is an upwardly facing shoulder, one of which is visible at  82 . The shaft  71  has a cylindrical eccentric portion  83  that projects downwardly from a bottom surface of the lower portion  86 . The eccentric portion  83  has an axis  84  that is parallel to but offset radially from the axis of rotation  72  of the shaft  71 . In the disclosed embodiment, the shaft  71  is made of steel, but it could alternatively be made of any other suitable material. 
   With reference to  FIGS. 2 and 5 , the shaft  71  extends through and is rotationally supported by the bushing  61 . The lower portion  76  of the shaft has a bottom surface that is approximately flush with a bottom surface of the bushing  61 , and with the surface  38  on the base  21 . The shoulders  82  on the shaft  71  are approximately flush with a top surface of the bushing  61 , and with an adjacent surface on the base  21 . 
   With reference to  FIGS. 1 and 2 , the accessory mount  10  includes a locking lever  101 .  FIG. 6  is a diagrammatic perspective top view of the locking lever  101 . In the disclosed embodiment, the locking lever  101  is made of steel, but it could alternatively be made of any other suitable material. The locking lever  101  has a disk-shaped portion  102  at one end, and an arm  103  extending outwardly from the disk-shaped portion  102 . The locking lever  101  is generally platelike, except that the outer end of arm  103  is thicker than the rest of lever  101 . The lever  101  has a flat top surface  104 . Near the outer end of the arm  103 , three spaced cylindrical openings  106 ,  107  and  108  each extend downwardly from the top surface  104  into the thicker part of the arm  103 . The openings  107  and  108  each extend completely through the arm  103 . The opening  106  extends only partway through the arm  103 . The disk-shaped portion  102  has in the center thereof a slot  111  that extends vertically through the portion  102 . 
   With reference to  FIGS. 2 ,  5  and  6 , the slot  111  in the lever  101  receives the upper part of the middle portion  77  of the shaft  71 . The flat surfaces  81  on opposite sides of the shaft  71  engage the flat surfaces on opposite sides of the slot  111 , so that the lever  101  is fixed against rotation with respect to the shaft  71  about the axis  72 . The disk-shaped end portion  102  of the lever  101  has a bottom surface that engages the upwardly-facing shoulders  82  on the shaft  71 , and that slidably engages a top surface of the bearing  61 . With reference to  FIG. 2 , a nut  116  engages the threaded upper portion  78  of the shaft  71 , in order to keep the locking lever  101  in position on the shaft  71 , and in order to keep the shaft  71  within the bushing  61 . 
   With reference to  FIG. 1 , a locking slide  121  is movably supported on the outer end of the arm  103  of the lever  101 .  FIG. 7  is a diagrammatic perspective top view of the locking slide  121 , and  FIG. 8  is a diagrammatic perspective bottom view of the locking slide  121 . In the disclosed embodiment, the locking slide  121  is made of aluminum or an aluminum alloy, but it could alternatively be made of any other suitable material. The locking slide  121  has a top surface  122 , and a bottom surface  123 . A recess  126  of approximately oval shape extends upwardly into the locking slide  121  from the bottom surface  123 . At one end of the locking slide  121 , the recess  126  opens laterally outwardly through a side wall of the slide, as indicated at  127 . Horizontal ribs  128  and  129  are provided on opposite sides of the recess  126  adjacent the bottom surface  123 , and each project inwardly a short distance. Each of the ribs  128  and  129  defines an upwardly facing shoulder, one of which is visible at  131 . At the end of the slide  121  opposite from the open end  127  of the recess  126 , a slot  136  extends vertically downwardly from the top surface  122  and opens into the recess  126 . 
     FIG. 9  is a diagrammatic top view of the locking lever  101 , with the slide  121  movably supported thereon.  FIG. 10  is a diagrammatic sectional view taken along the section line  10 - 10  in  FIG. 9 . With reference to  FIG. 10 , an upper end of the recess  126  in the slide  121  is defined by a downwardly-facing top surface  141 . The top surface  141  has two spaced, shallow recesses  142  and  143  that each have the shape of a portion of a sphere. The thick outer end of the arm  103  on lever  101  extends into the recess  126  through the open end  127 , and is slidable within the recess  126 . The upwardly facing top surface  104  of the lever  101  slidably engages the downwardly facing top surface  141  in the recess  126 . A bottom surface  146  on the thick end of arm  103  slidably engages the upwardly facing shoulders  131  on each of the ribs  128  and  129 . A tubular slotted spring pin  151  is made of steel, and is snugly received with a force fit in the vertical opening  108  of the lever arm  103 . The upper end of the pin  151  extends beyond the top surface  104  of the lever, and is slidably received within the slot  136  in the slide  121 . The upper end of the pin  151  can engage opposite ends of the slot  136  in order to limit sliding movement of the slide  121  relative to the lever arm  103 . 
   A detent mechanism is disposed within the opening  106  in the lever arm  103 , and includes a metal coil spring  161  disposed in the lower portion of the opening  106 , and a steel ball bearing  162  disposed in the upper portion of the opening  106 . The spring  161  resiliently urges the ball bearing  162  upwardly. The slide  121  can move with respect to the arm  103  between a locking position and a release position in which the ball bearing  162  respectively engages the recesses  142  and  143 . As the slide  121  is moved from one position to the other, the ball bearing  162  is forced downwardly against the urging of the spring  161  as it leaves one recess, and then is moved back upwardly by the spring  161  when it reaches the other recess. 
   With reference to  FIGS. 1 and 2 , a threaded stud  171  has its upper end threadedly engaging the threaded opening  36  ( FIGS. 2 and 3 ) in the base  21 . This end of the stud  171  is fixedly secured within the opening  36  by a commercially-available adhesive, such as a cyanoacrylate adhesive. In the disclosed embodiment the stud  171  is made of steel, but it could alternatively be made of any other suitable material. 
   Referring to  FIGS. 1 and 2 , the accessory mount  10  also includes a platelike locking blade  173  that, in the bottom view of  FIG. 1 , has an approximately rectangular shape. In the disclosed embodiment the locking blade  173  is made of steel, but it could alternatively be made of any other suitable material. The locking blade  173  has two slots  176  and  177  that open vertically therethrough. The slot  176  extends approximately parallel to the direction  52 , and the slot  177  extends approximately parallel to the direction  16 . The locking blade  173  has an end surface  178  ( FIG. 2 ) that is adjacent to the side  28  of the channel  23  in the base  21 , and that is inclined at approximately 90° with respect to the surface defining the side  28  of the channel. The surfaces  28  and  178  together define a V-shaped groove that can slidably receive the outwardly tapered edge  14  of the rail  12 . 
   The locking blade  173  has a top surface  181  that is slidably disposed against the downwardly facing surface  38  on the base  21 . The groove  176  in the locking blade  173  slidably receives the threaded stud  171 , and the groove  177  slidably receives the eccentric portion  83  of the shaft  71 . The locking blade  173  is disposed between the guides  48  and  49  on the base  21 , and each guide  48  and  49  slidably engages a respective side edge of the locking blade  173 . 
   A locking nut  182  is threadedly engaged with the outer end of the threaded stud  171 , and slidably engages the bottom surface of the locking blade  173 . With reference to  FIG. 2 , a multiwave compression spring  186  is disposed within the annular groove  37 , and slidably engages the top surface  181  of the locking blade  173 . In the disclosed embodiment, the multiwave compression spring is obtained commercially as part number MW0375-0150-04S from Associated Spring Raymond, Barnes® Group Inc., of Maumee, Ohio. However, it would alternately be possible to use some other type of spring arrangement. 
   The multiwave compression spring  186  resiliently urges the locking blade  173  downwardly away from the base  21 . Downward movement of the locking blade  173  under the urging of the spring  186  is limited by sliding engagement of the locking blade  173  with the locking nut  182  on the stud  171 . By rotating the locking nut  182 , the vertical position of the nut  182  on the stud  171  can be varied, and this in turn determines the vertical position of the end of locking blade  173  having the inclined end surface  178 . Thus, by turning the locking nut  182 , the surface  178  can be adjusted vertically with respect to the adjacent surface on base  21  that defines side  28  of the channel  23 . 
   A brief description of the operation of the accessory mount  10  will now be provided. With reference to  FIGS. 1 and 2 , the lever  101  can be manually pivoted about the vertical axis  72 , thereby rotating the attached shaft  71  about the axis  72 . In response to this rotational movement of the shaft  71 , the eccentric portion  83  of the shaft, through cooperation with the slot  177  in locking blade  173 , moves the locking blade  173  horizontally with respect to base  21 , parallel to the direction  52 . During this movement, the threaded stud  171  slides within the slot  176 . 
   If the lever  101  is pivoted counterclockwise in  FIG. 1  from the illustrated position through an angle less than 180°, the locking blade  173  is moved horizontally outwardly, or in other words downwardly in  FIG. 1  and rightwardly in  FIG. 2 . This moves the end surface  178  on the locking blade away from the channel  23  in the base  21 , so that the rail  12  can be inserted into or removed from the channel. Assume that the rail  12  is inserted into the channel  23 . The lever  101  is then pivoted clockwise in  FIG. 1  back to the position illustrated in  FIG. 1 . As this occurs, the locking blade  173  is moved inwardly, or in other words upwardly in  FIG. 1  and leftwardly in  FIG. 2 . This causes the end surface  178  on the locking blade to move to the position shown in  FIGS. 1 and 2 , where the rail  12  is retained within the channel  23 . The geometry of the mechanism is such that, as the lever  101  is pivoted clockwise, the manual force needed to move the lever decreases, even as the rail is being gripped more tightly. Also, the eccentric portion  83  moves through an over-center position in relation to the Locking blade  173 , such that the lever  101 , the shaft  71  and the locking blade  173  all tend to remain in their locking positions. 
   With reference to  FIG. 1 , when the lever  101  is in this locking position, the slide  121  is aligned with the tab  47  on the base  21 , and the slide  121  can be manually moved inwardly to its locking position, causing the tab  47  to be captured within the recess  126  in the slide. In this position of the slide  121 , the cooperation of the slide  121  with the tab  47  holds the arm  101  against pivotal movement. Of course, as discussed above, the eccentric portion  83  is in an over-center position in relation to the locking blade  173 , and thus the lever  101  would tend to remain in its locking position even without engagement of the slide  121  with the tab  47 . However, engagement of the slide  121  with tab  47  avoids inadvertent movement of the lever  101  away from its locking position, for example where the firearm is being carried and the lever  101  is accidentally bumped against a stationary object such as a door frame. Eventually, the slide  121  can be manually moved outwardly to the position shown in  FIG. 1 , thereby releasing the tab  47  from the slide, so that the lever  101  can again be manually pivoted. 
   With reference to  FIG. 2 , the spring  186  urges the locking blade  173  downwardly against the locking nut  182 . The locking nut  182  can be turned to adjust its vertical position on the stud  171 , thereby adjusting the vertical position of the end surface  178  of locking blade  173  with respect to the surface defining side  28  of channel  23  in base  21 . This permits the accessory mount  10  to be adjusted to readily accommodate dimensional variations from one Picatinny rail  12  to another. In particular, it ensures that the accessory mount  10  can be easily adjusted to securely grip any Picatinny rail  12 , without being too loose or too tight. By avoiding a situation where the grip is too tight, there is no risk that a manual force needed to move the lever  101  to its locking position would be so great that it might bend or even break the lever  101 . Since the locking blade  173  moves transversely with respect to the rail  12 , the end surface  178  thereon does not rub against and abrade the locking rail  12  as the locking blade moves to and from its locking position. Since the lever  101  pivots through an angle less than 360°, and in fact less than 180°, the disclosed locking mechanism is a quick-release arrangement that permits the accessory mount  10  to be rapidly mounted on or dismounted from the rail  12 . 
   Although a selected embodiment has been illustrated and described in detail, it should be understood that a variety of substitutions and alterations are possible without departing from the spirit and scope of the present invention, as defined by the claims that follow.