Patent Publication Number: US-8112933-B1

Title: Mounting assembly with adjustable spring tension and pivoting lock lever

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to earlier filed U.S. Provisional Application Ser. No. 61/295,824, filed Jan. 18, 2010, and is a continuation-in-part of U.S. Ser. No. 12/271,309, filed on Nov. 14, 2008, now U.S. Pat. No. 7,905,045, which is a continuation-in-part of U.S. patent application Ser. No. 11/933,506, filed Nov. 1, 2007, now U.S. Pat. No. 7,757,423, which is related to and claims priority from earlier filed U.S. Provisional Patent Application No. 60/864,022, filed Nov. 2, 2006. The entire contents of all earlier filed applications are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to modular integrated accessory mounting assemblies for combat weapons. More specifically, the present invention relates to an accessory mounting assembly, which includes a clamping assembly that provides adjustable spring tension to control the clamping force exerted against the firearm interface rail. 
     2. Background of the Related Art 
     As the field of combat and commercial weaponry expands, numerous add-on enhancements have become available for attachment to standard firearms, thereby significantly upgrading the capability of the firearm. Of particular interest in the area of combat weapons is the well-known M16/M4 weapon system (M16 and M4 are trademarks of Colt Defense, Inc.). The M16 has been in service for a number of years and will continue to be a popular rifle both in U.S. and foreign militaries for the foreseeable future. Generally, the M16/M4 weapon  2 , as depicted in  FIG. 1 , includes a lower receiver  4 , upper receiver  6 , butt stock  8 , and barrel  10 . 
     The newer models of the M16/M4 weapons further include a mil-std 1913 dovetail rail  12  extending along the top of the upper receiver. This integrated receiver rail  12  provides a convenient mounting point for many types of enhancement devices such as scopes and other sighting devices. 
     In addition, many supplemental rail systems for M16/M4 weapons have also been created. As shown in  FIG. 2 , these supplemental rail interface systems for weapons  2  generally include an upper hand guard  14 , a means  16  for securing the upper hand guard  14  to the weapon  2 , a lower firearm accessory  18  (in most cases this is a lower hand guard), various optional rail segments, and in many cases, a sling swivel  20  for attaching a shoulder sling to carry the weapon  2 . The upper hand guard  14  is generally semi-cylindrical in shape and has a forward end and a rearward end and a mil-std 1913 dovetail rail  22  extending longitudinally between the forward end and the rearward end. 
     The increasing development and refinement of laser sights, infrared lighting, visible lighting, night vision, and specialized scopes and magnifiers, and other accessories continues to drive the need for versatile and reliable integration systems that can support this important equipment and yet stand the test of rugged military use and abuse. 
     An existing attachment device is disclosed in U.S. Pat. No. 5,276,988, issued on Jan. 11, 1994 to the present applicant, the contents of the &#39;988 patent being incorporated herein by reference. Generally, the prior art attachment assemblies include a main body  24  having a lower portion that is configured to engage the dovetail rail  22  found on most modern combat weapons  2  and an upper portion  26  that can take on a variety of configurations depending on the accessory that is to be mounted thereon. The lower portion of the attachment assembly has a first engagement member  28  extending downwardly along one side thereof for engaging one side of the dovetail rail  22 . Further, a boss formation  30  is provided adjacent the side of the main body  24  to receive a clamping assembly  32  that is particularly suited to be releasably engaged with a second side of the dovetail rail such that the clamping assembly  32  cooperates with the first engagement member to retain the attachment assembly in its installed position on the dovetail rail  22 . The clamping assembly  32  generally includes a foot portion  32 A with a cam surface  32 B to engage the angulated surface of the dovetail rail  12 , a post extending upwardly through the boss formation  30  and a head portion  32 C secured to the top end of the post and having actuator arm  32 D to facilitate rotation of the foot portion  32 A. The clamping assembly  32  further includes spring washers, which are captured between the bottom surface of the head portion  32 C and the boss  30  (or a bushing within the boss) to provide a self-adjusting amount of spring tension as the clamping assembly  32  is rotated into engagement with the dovetail rail  22 . These springs generally allow a limited, self-adjusted amount of biased vertical movement of the foot portion  32 A relative to the boss  30  and the dovetail rail  22 . Because the head portion  32 C of the clamping assembly  32  is secured in a fixed position on the top end of the post, the spring are compressed by a fixed amount and therefore the force exerted by the foot portion  32 A on the dovetail rail  22  was generally variable, but variable only within a certain range as determined by the initial spring tension. This small range of self-adjustment is critical in being able to accommodate the small dimensional variations in the dovetail rails  22  of various equipment manufacturers. 
     Further, when such devices are employed with sighting accessories it is critical that the alignment of the device be repeatable and reliable after several removal and reinstallation cycles. If the camming force is too loose, the sight cannot be reinstalled with a high degree of accuracy. Similarly, if the camming force is too great, rotation of the foot portion  32 A can damage the dovetail rail  22  creating a sloppy fit over time. 
     Finally, despite the benefits of a fixed, self-adjusting range of spring tension provided by the prior art device, in certain environments, there is still a perceived need to adjust the range of the spring tension, for example if dovetail rails have excessive wear there may be a need to slightly increase the initial spring tension. However, there is also a desire to prevent the user of the weapon  2  from being able to adjust the tension without some type of restriction. Tighter is not better in these circumstances and over tightening can lead to damage to the rail  22  of the weapon  2 . Accordingly, while a need for adjustment may be accommodated, it should be provided in a manner that accommodates all of the environmental variables while still allowing the accessory mount to be ruggedly attached to the rail  22 . There is thus a struggle between the benefits of a fixed mounting so as to provide a fixed, self-adjusting range of spring tension, and the perceived need to be able to adjust the range of the spring tension. 
     Accordingly, there is a perceived need for a mounting assembly that allows for the releasable mounting of various accessories onto the standard dovetail rail  22  found on modern combat weapons  2  and that can be reliably mounted onto a dovetail rail  22  while including an actuator that includes the ability to adjust the spring tension that is exerted by the clamping foot. 
     SUMMARY OF THE INVENTION 
     In this regard, the present invention provides for an improved mounting assembly that is configured to be releasably attached to a standard dovetail rail profile wherein the clamping tension of the clamping assembly is adjustable. 
     The mounting assembly of the present invention generally includes a main body having a lower portion that is configured to engage the dovetail rail found on most modern combat weapons and an upper portion that can take a variety of configurations depending on the accessory that is to be mounted thereon. A boss formation including an opening extends outwardly to the side of the main body. A bushing including a central opening is mounted within the opening of the boss formation. The lower portion of the main body has a first engagement member extending downwardly along one side thereof for engaging one side of the dovetail rail. 
     The clamping assembly comprises a foot portion positioned adjacent the bottom surface of the boss formation and an actuator arm extending from the foot portion. The foot portion includes a cam surface similar to the prior art foot portion. A shaft extends upwardly from the top surface of the foot portion through the opening in the bushing. At least one spring is received around the shaft adjacent the upper surface of the bushing, and a retention nut is threaded onto the upper end of the shaft such that the spring is captured between the bottom surface of the retention nut and the upper surface of the bushing. The spring is compressed as the retention nut is tightened thereby providing for adjustment of the spring tension of the clamping assembly. 
     The retention nut includes a plurality of indexing slots around the peripheral edge thereof as well as a plurality of corresponding indexing marks on the upper surface of the retention nut for reference by the operator. 
     To insure that the retention nut remains in the position set by the user, actuator arm includes a spring-biased indexing and lock lever that engages the indexing slots on the outer surface of the retention nut. 
     The indexing and lock lever is pivotally mounted on the actuator arm adjacent to the retention nut. The index and lock lever is configured and arranged with a blade end that engages in the indexing slots in the retention nut and an actuator end that is moved by the user to move the blade end into and out of engagement with the retention nut. 
     The lock lever is pivotally mounted about a horizontal pin extending through the actuator arm so that downward movement of the actuator end of the lever causes upward movement of the blade end. The lock lever is normally biased by a spring to a down or engaged position with the retention nut. The spring is captured in the actuator arm between a recess on the actuator arm and a bottom surface of the actuator end of the lever. 
     Pivoting movement of the lock lever may be reversed to the lower side of the actuator arm with the pivot pin in the same location so that a forward movement of the actuator end would cause a corresponding upward movement of the blade end. The actuator pin remains in the same location, and the lever extends through the actuator arm to the lower side thereof. 
     Accordingly, it is an object of the present invention to provide an improved mounting assembly that allows for the releasable mounting of various accessories onto the standard dovetail rail found on modern combat weapons. Further, it is an object of the present invention to provide a mounting assembly that can be reliably mounted onto a dovetail rail while including an actuator that includes the ability to adjust the spring tension that is exerted by the clamping foot. It is still a further object of the present invention to provide a mounting assembly having an adjustable actuator that further includes a retention nut that allow a user to predictably and reliably control the spring tension and clamping force of the mounting assembly. 
     These, together with other objects of the invention, along with various features of novelty that characterize the invention, are pointed out with particularity in the claims annexed hereto and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated a preferred embodiment of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings which illustrate the best mode presently contemplated for carrying out the present invention: 
         FIG. 1  is a side view of a prior art combat firearm; 
         FIG. 2  is a perspective view of a prior art rail interface system; 
         FIG. 3A  is an end view of a prior art mounting assembly in the engaged position; 
         FIG. 3B  is an end view of a prior art mounting assembly in the disengaged position; 
         FIG. 4  is a perspective view of the mounting assembly of the present invention; 
         FIG. 5  is a right side view of the mounting assembly of the present invention; 
         FIG. 6  is a top view of the mounting assembly of the present invention; 
         FIG. 7  is a bottom view of the mounting assembly of the present invention; 
         FIG. 8  is an exploded perspective view of the mounting assembly of the present invention; 
         FIG. 9  is a partial view of the foot assembly of the mounting assembly of the present invention; and 
         FIG. 10  is a cross-section view through line  10 - 10  of  FIG. 9 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Now referring to the drawings, the mounting assembly is shown and generally illustrated at  40  in  FIGS. 4-10 . The mounting assembly  40  is configured to be releasably attached to a standard dovetail rail profile  12  as is depicted in  FIG. 1 , and includes a means for adjustment to control the clamping force exerted by the mounting assembly  40  against the dovetail rail  12 , as will be discussed in more detail below. The mounting assembly  40  of the present invention is particularly suited for use in connection with any firearm  2  that utilizes a standard dovetail rail  12  or the dovetail rail  22  of a supplemental rail system as depicted in  FIG. 2 . The mounting assembly  40  is also suitable for use with any weapon system or device that utilizes a dovetail rail as a platform for attachment. 
     Turning now to  FIG. 4 , as can be seen, the mounting assembly  40  includes a main body  42  that is configured in substantially the same manner as a traditional prior art device and further includes a lower portion  43  that is configured to engage the dovetail rail  12  found on most modern combat weapons  2  and an upper portion  44  that can take on a variety of configurations depending on the accessory that is to be mounted thereon. As can best be seen in  FIG. 6 , the lower portion  43  of the main body  42  has a first engagement member  46  extending downwardly along one side thereof for engaging one side of the dovetail rail  12 . Opposite the first engagement member  46 , a boss formation  48  is provided adjacent the side of the main body  42  wherein the boss formation  48  includes a large central opening  50  therein to receive a clamping assembly generally indicated at  52 . An annular bushing  64  with a smaller central opening  65  is installed into the large central opening  50 . 
     Turning back now to  FIG. 4 , in the scope of the present invention, the clamping assembly  52  replaces the clamping assembly of the prior art as is depicted in  FIGS. 3A and 3B . In the present invention, the clamping assembly  52  is configured to releasably engage a dovetail rail interface  12  with a self-adjusting clamping force that has an adjustable range of spring tension. The clamping assembly  52  and the first engagement member  46  cooperate to hold the main body  42  on the dovetail rail  12 . 
     The clamping assembly  52  is received into and supported by the boss formation  48  that extends outwardly from the side of the body  42  of the mounting assembly  40 . The clamping assembly  52  generally includes a foot portion  54  that is positioned adjacent the bottom surface of the boss  48  formation. The foot portion  54  includes an angulated cam surface  55  that extends around the side surface of the foot portion  54  as in the prior art devices. However, in contrast to the prior art as described, the actuator arm  56  extends outwardly directly from the foot portion  54  below the boss formation  48  rather then being attached to the foot above the boss formation. The foot portion  54  may be configured as a dual-sided foot so that only one foot and arm need be provided for either left or right hand mounting assemblies. The actuator arm  56  extends outwardly directly from the foot portion  54  below the boss formation  48  and allows the user to rotate the foot portion  54  between engaged and disengaged positions. A shoulder  59  extending from said boss  48  formation may be provided to prevent said actuator arm  56  from being rotated passed said disengaged position. A shaft  58  is affixed to and extends upwardly from the foot portion  54  through the bushing  64  and terminates in a threaded end  60 . 
     At least one spring  70  in the form of a coil spring or spring washer is received around the shaft  58  and is seated on the bottom wall of the bushing  64 . 
     A retention nut  62  having a threaded bore  63  is threadedly received on the threaded terminal end  60  of the shaft  58  such the spring  70  is captured between the bottom surface of the retention nut  62  and the upper surface of the bottom wall of the bushing  64 . The spring  70  is compressed as the retention nut  62  is tightened thereby providing for adjustment of the initial spring tension of the clamping assembly  52 . 
     There is also shown a steel buffer pad  72  having a flat horizontal base portion with an arm  74  at each end of the base extending upwardly at an oblique angle of 135 degrees. The free end of each arm  74  is curved approximately 150 degrees. Two side-by-side openings  76 , corresponding in separation to the separation between buffer pad arms  74 , are formed in the main body  42 . The arms  74  of the buffer pad  72  are slid through the openings  76 . In operation, the buffer element  72  sits between the angulated surface of the rail  12  and the cam surface  55  of the foot portion  54 . Rotation of the actuator arm  56  causes the foot portion  54  to press the buffer element  72  into the side of the firearm rail  12 . The buffer element  72  prevents the foot portion  54  from directly touching and thereby marring the outer surface of the firearm rail  12 . Rotation of the actuator arm  56  and the consequent movement of the foot portion  54  against the buffer element  72  overcomes the resistance of the spring washers  70  and moves the buffer element  72  against the engagement surface of the rail interface  12 . The foot portion  54  may further include a recess  73  thereon to hold a magnet  77 . In the disengaged position, the magnet  77  will pull the buffer pad  72  towards the foot portion  74  and away from the first engagement member  46  thereby allowing the mounting assembly  40  to be easily removed or place on the rail without the buffer pad  72  swinging in the way. 
     To insure that the retention nut  62  remains in a position as set by the user, the clamping assembly  52  further comprises a locking means for positively locking the position of the retention nut  62  on the threaded shaft  58 . The locking means preferably comprises at least one locking formation (indexing slot)  82  on the outer edge surface  80  of the retention nut  62  and a pivoting lock lever  84 . The indexing slots  82  extend all the way around the outer surface  80  of the retention nut  62  to provide a wide range of adjustment. Indexing marks  83  may also be provided on the top surface of the retention nut  62  to allow a user to determine the amount of spring tension being applied. The lock lever  84  is received within a cradle  85  formed in the handle portion of the actuator arm  56  and is held in place by a roll pin  87 . The lock lever  84  includes a blade end  90  that engages in the indexing slots  82  in the retention nut  62  and an actuator end  92  that is pressed by the user to move the blade end  90  into and out of engagement with the indexing slots  82  on the retention nut  62 . 
     The lock lever  84  is pivotally mounted about a roll pin  87  extending through the cradle  85  of the actuator arm  56  so that downward movement of the actuator end  92  of the lock lever  84  causes upward movement of the blade end  90 . The lock lever  84  is normally biased by a spring  94  to a down or engaged position with the indexing slots  82  on the retention nut  62 . The biasing spring  94  is captured in the actuator arm between a recess  96  on the actuator arm  56  and a bottom surface of the actuator end  92  of the lock lever  84 . 
     Because the spring  70  is trapped between the retention nut  62  and the bushing  64 , tightening of the retention nut  62  causes compression of the spring  70 , shortens the range of the vertical travel of the foot portion  54  relative to the bottom surface of the boss  48  and increases the spring clamping force. Accordingly, when the actuator arm  56  rotates the foot portion  54  into engagement with the rail  12 , additional spring pressure is exerted on dovetail rail  12 . Similarly, as the retention nut  62  is loosened, the compression of the spring  70  is reduced, the range of vertical travel of the foot portion  54  is increased, and the clamping force is reduced. In order to tighten or loosen the retention nut  62 , the actuator end of the lock lever  84  is pressed down relative to the actuator  56  until the blade end of the locking pin  84  is clear of the indexing slots  82  in the retention nut  62  thereby allowing rotation of the retention nut  62  relative to the clamping assembly  52 . After the retention nut  62  is adjusted and the desired spring tension is set, the actuator end of the lock lever  84  is released and the blade end is allowed to engage with the indexing slots  82  on the retention nut  62  preventing rotation of the retention nut relative to the clamping assembly  52 . 
     It can further be appreciated that the actuator end  92  of the lock lever  84  may include texturing or knurling thereon to facilitate pressing of the lock lever  84  by hand. 
     Accordingly, it can be seen that the present invention provides a unique and novel modular accessory mount that fills a critical need for soldiers in the field by ensuring positive and reliable operation. For these reasons, the instant invention is believed to represent a significant advancement in the art, which has substantial commercial merit. 
     While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.