Abstract:
A slide-action stock for a semi-automatic firearm. The side-action stock includes a handle provided with an integral finger rest. The finger rest forms a cradle for the user&#39;s trigger finger. In use, the user grasps the handle with one hand while pressing the dorsal side of their index finger firmly against the cradle. When intending to fire a round of ammunition, the user pushes the receiver forward with their other hand so that the trigger collides with the stabilized index finger. Recoil force quickly separates the trigger from the user&#39;s finger against the cradle. The user pushes the receiver forward to repeat the firing cycle. A firing mode selector can be selectively engaged to restrict longitudinal movement of the trigger relative to the handle, thereby returning the firearm to normal semi-automatic functionality.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Provisional Patent Application No. 61/667,777 filed Jul. 3, 2012, the entire disclosure of which is hereby incorporated by reference and relied upon. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to firearms, and more particularly toward a manually reciprocated slide-action stock for semi-automatic firearms. 
         [0004]    2. Related Art 
         [0005]    Various techniques and devices have been developed to increase the firing rate of semi-automatic firearms. Many of these techniques and devices make use of the concept known as rapid-action or “bump firing”, which is the manipulation of the recoil of the firearm to rapidly activate the trigger. One such rapid-action firing technique is known as the “belt loop” method. To execute the belt loop method, the shooter first places the firearm next to his or her hip and hooks one finger through both the trigger guard (in front of the trigger) and a belt loop in his or her clothing. The opposite hand is placed on the forward hand guard attached to the barrel of the firearm. When the firearm is tugged forward by the shooter, the trigger is activated by the hooked finger to discharge a bullet. The recoil from the bullet pushes the firearm backwards away from the trigger finger, allowing the trigger to re-set. Forward force must be applied to the hand guard in order to activate the firing mechanism for each round that is fired. However, this may be achieved in very rapid succession. 
         [0006]    Although able to achieve a high rate of firing, the belt loop method has many safety and accuracy issues. For example, to correctly operate many firearms with the belt loop method, the operator&#39;s arm must be placed in the path of hot gasses being expelled from the ejection port of the firearm. This could lead to skin burns or possibly pinch the operator&#39;s sleeve or skin in the action. Another issue with the belt loop method arises because the operator cannot have a firm grip on the firearm. Because the belt loop method only works if the firearm is held loosely with one hand, the chances of the operator losing control of the firearm are greatly amplified. Because of this unnatural and unbalanced firing grip, the firearm is very difficult to aim and control during the belt loop method. 
         [0007]    Commercial devices are also available for assisting in the rapid-action firing concept, including the HELLSTORM 2000 and TAC Trigger. Both of these are small devices that mount to the trigger guard of the firearm and use springs to aid in quickly resetting the trigger while the firearm is rapid-action fired, as described above. However, the same safety and accuracy issues of the belt loop method apply to these devices because the firearm cannot be held securely with the trigger hand or the stock of the firearm. 
         [0008]    The slide-action stock concept marked under the trademark Slide Fire® pioneered by Slide Fire Solutions LP, Moran, Tex., has become a popular accessory enabling rapid fire capability to semi-automatic rifles without compromising safety. In use, a user pulls their trigger finger rearwardly against a specially designed rest adjacent the trigger while holding the butt section of the rifle snug against their shoulder in a normal shooting posture. Forward pressure is applied to the front hand-guard to initiate shooting. The user remains in complete control as the rifle continues to fire while forward pressure is maintained on the front hand-guard. For a more complete description of the Slide Fire) slide-action stock, reference is made to U.S. Pat. Nos. 8,127,658; 8,176,835; 8,356,542; 8,371,208; 8,448,562; 8,459,171 and 8,474,169, the entire disclosures of which are hereby incorporated by reference and relied upon. 
         [0009]    There exists a continuing need for further improvements in devices that will allow the shooter to practice new and interesting ways to shoot firearms in a legal and safe manner, to increase the firing rate of semi-automatic firearms without compromising the safety of the operator or the accuracy of the firearm, which are generally universally functional without respect to ammunition type, and which are sufficiently distinguished from a fully automatic weapon so as to fall within compliance of federal firearms regulations. There exists further a need for an improved interface device or system disposed operatively between the firing unit of a firearm and the handle portion of a firearm that is durable, sturdy, and not prone to binding in use. 
       SUMMARY OF THE INVENTION 
       [0010]    According to one aspect of this invention, a slide-action stock for a semi-automatic firearm includes a handle adapted to be grasped by a user&#39;s hand. The handle includes an opposing surface for directly interacting with a bearing element of the firearm so that the handle is able to reciprocate relative to the bearing element back-and-forth along a constrained path. The slide-action stock also includes a finger rest configured to stabilize the end of a user&#39;s trigger finger in a partially extended condition so that in use the user&#39;s trigger finger stretches in front of the firearm trigger while the remaining fingers of the user&#39;s hand grasp the handle. The finger rest and the handle are fixed together as a unit for concerted back-and-forth movement along the constrained path. The finger rest has a rearwardly facing cradle against which the dorsal portion of a user&#39;s trigger finger is pressed in a forwardly acting direction while the remaining fingers of the user&#39;s rear hand grasp the handle. 
         [0011]    According to another aspect of this invention, a method is provided for rapid-firing a semi-automatic firearm using a slide-action stock. The method includes the steps of: supporting a firing unit portion of a firearm in a handle for back-and-forth movement relative to the handle, the firing unit includes a trigger, grasping the handle with a hand of the user, and stabilizing an index finger of the user&#39;s hand in a partially extended condition stretched in front of the trigger. The stabilizing step includes pressing the dorsal portion of the user&#39;s finger forwardly against a rearwardly facing cradle. 
         [0012]    This invention fulfills many needs in the sporting arms field, including enabling shooters to practice new and interesting ways to shoot firearms in a legal and safe manner, increasing the firing rate of a semi-automatic firearm without compromising the safety of the user or the accuracy of the firearm, providing generally universal functional without respect to ammunition type, and in compliance with federal firearms regulations. This present invention represents an improved interface device disposed operatively between the firing unit of a firearm and the handle portion of a firearm that is durable, sturdy, and not prone to binding in use. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    These and other features and advantages of the present invention will become more readily appreciated when considered in connection with the following detailed description and appended drawings, wherein: 
           [0014]      FIG. 1  is a simplified side view of a firearm fitted with a sliding stock system according to one embodiment of the present invention; 
           [0015]      FIG. 2  is a an enlarged fragmentary view of the firearm of  FIG. 1  shown with stock and firing unit elements exploded apart; 
           [0016]      FIG. 3  is a fragmentary perspective view of the trigger area of a firearm as in  FIG. 1 ; 
           [0017]      FIGS. 4A and 4B  are time sequence views of the fragmentary portion of the firearm as depicted in  FIG. 3  and showing relative movement between the stock and firing unit elements with a human finger operatively disposed on a finger rest of the present invention; 
           [0018]      FIG. 5  is an enlarged view of a human hand grasping a pistol grip portion of the sliding stock system; 
           [0019]      FIG. 6  is a highly enlarged view of the trigger region with a human finger operatively disposed on a finger rest and depicting a rearward recoiled position of the trigger in phantom; 
           [0020]      FIG. 7  is an exploded view of the finger rest and pistol grip according to one embodiment of the invention; 
           [0021]      FIG. 8  is a perspective view of the upper side of the finger rest of  FIG. 7 ; and 
           [0022]      FIG. 9  is a perspective view of the underside of the finger rest of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]    Referring to the figures wherein like numerals indicate like or corresponding parts throughout the several views, a semi-automatic firearm according to one exemplary embodiment of this invention is generally shown at  10  in  FIG. 1 . In the illustrated examples, the firearm  10  is depicted as a rifle or long gun; however the principles of this invention may be applied with success to hand guns and pistols. Therefore, those of skill in the art should appreciate that the term firearm as used throughout this patent application is applicable to all forms of semi-automatic projectile-firing devices. 
         [0024]    The firearm  10  includes a receiver  12  and a barrel  14  and a trigger  16  operatively connected together as a firing unit. Ammunition (not shown) fed into the receiver  12  (such as through a magazine  17  or a belt system) is presented into a firing chamber (not shown) at the base of the barrel  14 . A firing pin struck by a hammer (neither of which are shown) ignites a round of ammunition in the firing chamber when a user pulls the trigger  16 . In the context of this invention, the firing unit is provided with at least one bearing element, generally indicated at  18 . The bearing element  18  in this illustrative example is attached to the rearward end of the receiver  12 . The bearing element  18  may include a channel  20  along its undersurface as shown for example in  FIG. 3 , as will be described in further detail below. Those of skill in the art will appreciate that the bearing element  18  could take many different forms, and is not intended to be limited to the specific design shown in the accompanying illustrations. 
         [0025]    A slide-action stock, generally indicated at  22 , is interactive with the firing unit and includes a handle configured to provide an interface through which a user grasps the firearm with at least one hand. The slide-action stock  22  includes an opposing surface  24  that directly interacts with the bearing element  20  of the firing unit so that the firing unit is able to reciprocate relative to the slide-action stock  22  back-and-forth along a constrained path. In the illustrated embodiment, the opposing surface  24  is a rib-like T-track perhaps best shown in  FIG. 2 . The channel  20  has a complementary shape to facilitate sliding motion along a constrained linear path that is generally parallel to the length of the barrel  14 . It should be understood, however, that the bearing element  20  and opposing surface  24  can take many different cooperating forms that provide linear, curvilinear and/or pivotal relative motion so that the firing unit may achieve its reciprocating back-and-forth movement with respect to the slide-action stock  22 . Thus, the term “slide action” with reference to the stock  22  must not be construed so narrowly as to preclude an interpretation of pivotal motion at the bearing element  20 /opposing surface  24  interface accomplished through links are other means. 
         [0026]    The slide-action stock  22  is shown according to one exemplary embodiment in  FIG. 1  including a finger rest  26  and a handle. The handle includes a pistol grip  28  and a shoulder stock  30 . In alternative variations, however, the shoulder stock  30  portion may be omitted (as in pistol-type configurations) or the pistol grip  28  may be omitted (as in hunting/patrol rifle type configurations). For primarily ergonomic benefits, the pistol grip  28  may extend obliquely downwardly and away from the finger rest  26 . The pistol grip  28  and shoulder stock  30  are interconnected (in this example) through a connector bar  32 , upon which the opposing surface  24  is positioned. A cheek-piece  34  may optionally be affixed to or otherwise integrated with the shoulder stock  30  as shown in  FIG. 1 . 
         [0027]    As shown in  FIGS. 4A-6 , the finger rest  26  is configured to stabilize a finger  36  of the user&#39;s hand, and more specifically the shooter&#39;s index or trigger finger, in a partially extended and hooked position so that in use the user&#39;s finger  36  is stretched in front of the trigger  16  when it is desired to shoot the firearm  10 . The finger rest  26  has a rearwardly facing cradle  38  against which the dorsal portion of the user&#39;s finger  36  is pressed in use. The rearward direction is defined as generally opposite the direction a projectile travels as it exits firearm  10 . The arrow  40  in  FIG. 5  depicts the forwardly-directed force with which the user exerts on their finger  36  in order to maintain the dorsal side (i.e., fingernail side) pressed against the cradle  38 . In the illustrated embodiment, the cradle  38  is comprises a section of a continuous bounded inner periphery formed by a generally D-shaped loop or ring-like extension from the connector bar  32 . Although the finger rest  26  is a depicted as being generally oblong in appearance, alternate embodiments include loops of various shapes (e.g., circular, square, triangular, polygonal, regular or irregular). In still further embodiments, the “loops” may not actually form a closed loop, but may instead simply provide a surface (e.g., a surface similar to the cradle  38 ) upon which a shooter&#39;s finger  36  can rest and which inhibits the forward movement of the shooter&#39;s trigger finger  36 . 
         [0028]    The loop portion of the finger rest  26  may have a size generally equivalent to the firearm trigger guard  42 , and be positioned so that the finger rest  26  lies to the left side (as shown) or right side (not shown) of the trigger guard  42 . The finger rest  26  may be used by left-handed and right-handed shooters without the need to switch the finger rest  26  from one side of the trigger to the other. Nevertheless, while the embodiments disclosed herein generally depict finger rest  26  as being positioned on the left side of the trigger  16  when installed on the firearm  10  (which may be more intuitive to use by right handed shooters than by left-handed shooters), alternate embodiments include a loop positioned on the right side of the trigger  16 , and still further embodiments include a loop positioned on both sides of the trigger  16 . 
         [0029]    Detailed views of one embodiment of the finger rest  26  are shown in  FIGS. 7-9 . The finger rest  26  may include a mounting lug  44  formed with an threaded hole  46  and adapted to receive a standard replacement pistol grip  28  via a through-the-grip fastener  48 . The finger rest may optionally include an adjustable mounting structure that enables selective adjustment of the spacing between the cradle  38  portion of the finger rest  26  and the handle. In the one illustrated example, the adjustable mounting structure includes a series of mounting holes  50  that engage cooperating features on the connector bar  32  (not shown) and enable the extended length of the cradle  38  to be custom fit for any particular application. Of course, many alternative approaches can be contemplated to enable selective adjustment of the cradle  38  relative to the handle. 
         [0030]    In use, a semi-automatic firearm can be rapid-fired by a human user using the slide-action stock  22  by supporting the firing unit in the handle for back-and-forth movement relative to the handle, grasping the handle with a hand of the user, and stabilizing an index finger  36  of the user&#39;s hand in a partially extended condition stretched in front of the trigger  16 . The stabilizing step includes pressing the dorsal portion of the user&#39;s finger  36  forwardly (arrow  40 ) against the rearwardly facing cradle  38 . In order to fire one or more rounds of ammunition, the user manually pushes the firing unit forward relative to the handle with their other hand while grasping the handle and stabilizing the finger with the first hand. 
         [0031]    As depicted in  FIGS. 4A-6 , with the receiver  12  positioned in a rearward orientation with respect to stock  22 , the cradle  38  of finger rest  26  is positioned forward of trigger  16  (see  FIGS. 4A and 5 ). Conversely, when the receiver  12  is positioned in a forward orientation with respect to stock  22 , the cradle  38  of finger rest  26  is positioned nearer to the trigger  16  (see  FIGS. 4B and 6 ). Thus, relative movement of the cradle  38  relative to the trigger  16  occurs as receiver  12  moves between its forward orientation and its rearward orientation with respect to the slide-action stock  22 . 
         [0032]    When using a firearm  10  with the finger rest  26  installed, a shooter may place the shoulder stock  30  against the shooter&#39;s shoulder, grasp the pistol grip  28  with the shooter&#39;s trigger finger hand, insert the shooter&#39;s trigger finger  36  (or other suitable appendage or non-human trigger actuator) into the space in front of the trigger  16  and behind the cradle  38  of the finger rest  26 . The shooter may then place the dorsal side of the shooter&#39;s trigger finger  36  against the cradle  38  and bias the trigger  16  (and generally the entire firing unit) forward by grasping a forward grip  52  with the shooter&#39;s non-trigger hand and urging the forward grip  52  in a forward (downrange) direction. The forward urging can be described as using the shooter&#39;s arm strength to bias the forward grip  52  and the trigger  16  using human muscle power. 
         [0033]    As the trigger  16  moves forward in response to the shooter urging the forward grip  52  in the forward direction, the trigger  16  eventually contacts the shooter&#39;s trigger finger  36 . Contact between the trigger  16  and the shooter&#39;s trigger finger results in actuation of the trigger  16  (and the trigger group assembly). Consequently, a projectile is discharged from the firearm  10 . The discharging of the projectile results in a recoil force that moves the trigger  16  rearward against arm tension in the shooter&#39;s hand that remains grasping forward grip  52 —provided, of course, that the user&#39;s forward muscle effort is not greater than the recoil force. 
         [0034]    After the firing unit has moved rearward a sufficient distance in response to the recoil force, the trigger assembly resets, i.e., the trigger  16  rotates forward with respect to the trigger assembly a sufficient amount to reset the trigger assembly. When the trigger  16  is again pushed forward a sufficient distance by the shooter maintaining a forward urging force on the forward grip  52 , trigger  16  will be actuated a second time by the shooter&#39;s trigger finger  36 , and a second round will be discharged. This sequence may be repeated by the shooter maintaining an appropriate amount of forward pressure on the forward grip  52  to continue rapid-action firing the firearm  10 . 
         [0035]    The rapid-action firing of a firearm  10  will continue until the shooter&#39;s non-trigger hand and arm cease the forward biasing of the firing unit (or decreases the forward biasing by a sufficient amount), thereby resulting in the trigger  16  not moving sufficiently forward to actuate trigger  16  and discharge another projectile from firearm  10 . The firing of firearm  10  can also continue until the shooter&#39;s non-trigger hand and arm increase the forward biasing of the trigger  16  by an amount sufficient to overcome the recoil force and prevent trigger  16  from moving the rearward to reset the trigger  16  after a projectile is discharged from firearm  10   
         [0036]    The slide-action stock  22  may include an optional firing mode selector  54  can control the interaction (e.g., sliding interaction) between the slide-action stock  22  and the firing unit. The firing mode selector  54  may be oriented in either of two positions: one position to allow the trigger  16  to move in relation to the slide-action stock  22 , and the other position to inhibit relative motion between the trigger  16  and slide-action stock  22 . To operate the firearm  10  in a traditional semiautomatic manner, the shooter sets the firing mode selector  54  to restrict the movement between stock  22  and the receiver  12 . Using this method, one shot is discharged for each squeeze of the trigger  16 . 
         [0037]    Use of the finger rest  26  allows the shooter to transition from bump firing a firearm to firing the same firearm using traditional semi-automatic firing techniques and back again to bump firing the firearm without the need to move the shooter&#39;s trigger finger, which can provide a more seamless transition from bump firing to traditional semi-automatic firing techniques. When firing the firearm using a traditional semi-automatic firing technique, the finger rest  26  supplements the trigger guard  42  and inhibits accidental actuation of the trigger  16  while providing unobstructed access to the trigger  16  by the shooter&#39;s trigger finger. 
         [0038]    The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and fall within the scope of the invention.