Patent Publication Number: US-11035639-B2

Title: Firearm spring compression tool

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Continuation-in-Part of and claims priority in U.S. Non-Provisional patent application Ser. No. 16/223,487, filed Dec. 18, 2018, which claims priority in Provisional Patent Application No. 62/607,164, filed Dec. 18, 2017, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to firearm servicing, and in particular to a tool for compressing springs for firearm assembly and disassembly procedures. 
     2. Description of the Related Art 
     Firearm servicing procedures typically require disassembly and reassembly of various parts. For example, AR-15 (civilian model) and M-4 and M-16 (military models) rifles and carbines commonly include handguards enclosing their barrels and gas tubes. The handguards are configured for gripping by shooters, and are longitudinally split into separate (e.g., upper and lower) handguard halves. With the AR-15, M-4 or M-16 rifles assembled, the handguard halves are clamped together at their rear ends by compressible delta rings (“D-rings”). The handguard disassembly procedure includes compressing the D-ring to release the rear ends, and extracting the front ends of the handguard halves from a handguard front cap connected to the barrel. 
     Specialized tools have previously been developed for compressing D-rings. However, heretofore there has not been available a firearm spring compression tool with the features and advantages of the present invention. These include compactness for portability and simplicity of use. Another advantage relates to adaptability to different firearm models. 
     SUMMARY OF THE INVENTION 
     In practicing an aspect of the present invention, a firearm spring compression tool is provided for compressing a D-ring in connection with a handguard removal procedure. The tool generally includes a base configured for placement in a magazine receiver, a yoke engaging the D-ring and an actuator configured for flexing the yoke rearwardly on the firearm and thereby compressing the D-ring and releasing the handgrip rear ends. In practicing another aspect or alternative embodiment of the present invention, an extended base is configured for vice-mounting the compression tool and a firearm secured thereto. Another aspect of the invention includes a further modified base with a transversely-extending handle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings constitute a part of this specification and include exemplary embodiments of the present invention illustrating various objects and features thereof. 
         FIG. 1  is a fragmentary, side elevational view of an AR-15, M-4 or M-16 rifle, showing placement of a spring compression tool embodying an aspect of the present invention. 
         FIG. 2  is a side elevational view thereof, showing the tool in position for compressing a D-ring. 
         FIG. 3  is a front, lower, right side perspective, exploded view of the spring compression tool. 
         FIG. 4  is a rear, lower, right side perspective, exploded view of the spring compression tool. 
         FIG. 5.1  is a side, elevational view of the spring compression tool, taken generally within circle  5 . 1  shown in  FIG. 2 , with the D-ring and the handguard rear end engaged. A portion of the AR-15, M-4 or M-16 rifle is shown in broken lines. 
         FIG. 5.2  is a side, elevational view of the spring compression tool, with the D-ring and the handguard rear end disengaged. A portion of the AR-15, M-4 or M-16 rifle is shown in broken lines. 
         FIG. 6.1  is a front, lower, perspective view of the compression tool in a first position for placing the compression tool over a D-ring. 
         FIG. 6.2  is a front, lower, perspective view of the compression tool in a second position for releasing a handguard rear end from the compressed D-ring. 
         FIG. 7.1  is a lower, front, elevational view of the compression tool in a first position for placing the compression tool over the uncompressed D-ring. 
         FIG. 7.2  is a lower, front elevational view of the compression tool in a second, compression position for releasing the handguard rear end from the compressed D-ring. 
         FIG. 8  is a right side elevational view of a spring compression tool comprising a first modified or alternative embodiment of the present invention, shown with an adapter for an alternative D-ring configuration. 
         FIG. 9  is an upper, front, perspective view of the modified embodiment spring compression tool. 
         FIG. 10  is a lower, front, perspective view of the modified embodiment spring compression tool. 
         FIG. 11  is an exploded, lower, front, perspective view of a yoke and attachment of the modified embodiment spring compression tool. 
         FIG. 12  is an exploded, lower, rear, perspective view of the yoke and attachment of the modified embodiment spring compression tool. 
         FIG. 13  is an exploded, upper, front, perspective view of the yoke and attachment of the modified embodiment spring compression tool. 
         FIG. 14  is a front, right side perspective view of a spring compression tool comprising a second modified or alternative embodiment of the present invention, shown with an extended base. 
         FIG. 15  is left side elevational view of the extended base thereof. 
         FIG. 16  is a cross-sectional view of the extended base thereof, taken generally along line  16 - 16  in  FIG. 15 . 
         FIG. 17  is a left side elevational view thereof. 
         FIG. 18  is a rear view of a yoke thereof, taken generally along line  18 - 18  in  FIG. 17 . 
         FIG. 19  is a lower, front, right side perspective view of a spring compression tool comprising a third modified or alternative embodiment of the present invention, shown with a modified base with a transverse handle. 
         FIG. 20  is a right-side elevational view thereof. 
         FIG. 21  is a right-side elevational view of the modified base thereof. 
         FIG. 22  is a cross-sectional view of the modified base thereof, taken generally along line  22 - 22  in  FIG. 21 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     I. Introduction and Environment 
     As required, detailed aspects of the present invention are disclosed herein, however, it is to be understood that the disclosed aspects are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art how to variously employ the present invention in virtually any appropriately detailed structure. 
     Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, up, down, front, back, right and left refer to the invention as orientated in a use position. The words, “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the aspect being described and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof and words of similar meaning. 
     II. Firearm Spring Compression Tool  2   
     Referring to the drawings more detail, the reference numeral  2  generally designates a spring compression tool embodying an aspect of the present invention. Without limitation on the generality of useful applications of the present invention, the tool  2  is shown compressing a delta ring (“D-ring”)  4  on a firearm  6  for releasing a handguard  8 . The firearm  6  can comprise, without limitation, an M-16, an M-4 carbine, an AR-15, various models thereof, and other firearms. Removing the handguard  8  is a common procedure in connection with servicing the applicable firearms, and provides access to barrel, gas tube and other components. 
     The firearm  6  includes upper and lower receiver assemblies  10 ,  12  and a barrel  14  partially enclosed by the handguard  8 , which comprises upper and lower halves  16 ,  18  with rearwardly-projecting, arcuate flanges  20 . With the firearm  6  assembled, the D-ring  4  (also referred to as a delta ring and a retaining ring) is pressed forwardly into engagement with the handguard  8  rear end and captures the flanges  20 . A front cap  22  captures the front ends of the handguard halves  16 ,  18 . 
     The compression tool  2  facilitates service procedures by compressing the D-ring in connection with removing and installing the handguard  8 . The compression tool  2  includes a base  24 , which inserts into the magazine well or opening  26  of the lower receiver assembly  12  and anchors the tool  2  during use. A yoke  28  ( FIGS. 3, 4 ) includes a proximal portion  30  and a distal portion  32 , the latter extending generally upwardly with a U-shaped configuration including a pair of yoke arms  34 . The yoke distal portion  32  forms an opening  36  between the arms  34 . The opening  36  converges forwardly and generally mates with the forwardly-converging D-ring  4  with the tool  2  in place ( FIG. 2 ). The yoke  28  includes a bearing  38  connected to the proximal and distal portions  30 ,  32  ( FIGS. 6.1 and 6.2 ). 
     The yoke  28  rotatably mounts an actuator  40 , which includes a toggle  42  with a circular opening  44 . The actuator  40  includes a rearwardly-projecting actuator flange  46 . The flange  46  slopes from a minimum rearward-extension at a 1st (uncompressed position) stop  47   a  to a 2nd (compressed position) stop  47   b . The stops  47   a ,  47   b  engage the yoke  28  opposite sides, thus restricting the rotation of the actuator  40  between its respective uncompressed/compressed positions. Without limitation and by way of example only, the actuator  40  rotates through about a 315°-330° arc between its extreme positions. The flange  46  engages and slides along bearings  38  on the sides of the yoke proximate portion  30  as the actuator  40  is rotated between its extreme positions with the D-ring  4  uncompressed (handguard  8  retained) and compressed (handguard  8  released) positions. The tool  2  includes an axle bolt  48  extending through aligned receivers in the base  24 , the yoke  28  and a rearwardly-extending boss  49  of the actuator  40 . The axle bolt  48  is retained in place by a nut  50 , which is captured in the rear of the base  24  ( FIG. 4 ). 
     III. Operation 
     In operation, the compression tool  2  is installed by inserting the base  24  into the magazine well or opening  26  and the yoke  28  is placed over the D-ring  4 . In the placement configuration, the actuator  40  is fully rotated counterclockwise (when viewed from the front) to a starting position as shown in  FIG. 6.1 , with the toggle  42  on the left side of the firearm  6 . The actuator  40  is then rotated clockwise (when viewed from the front), placing the toggle  42  on the right side of the firearm  6 . The actuator flange  46  rides across the bearing  38 . Due to its tapered or spiral configuration, the flange  46  tilts or flexes the actuator  40 , tilting the yoke  28  rearwardly and thereby compresses the D-ring  4  captured therein. The base  24  cooperates with the lower receiver assembly  12  to securely anchor the compression tool  2 . With the D-ring  4  compressed rearwardly, the handguard flanges  20  are released from the D-ring  4  ( FIG. 5.2 ), enabling separating the handguard  8  from the front cap  22  and removal of the handguard halves  16 ,  18 . Reassembly can be accomplished by reversing the procedure described above, with the compression tool  2  retaining the D-ring  4  in a rear position until the handguard halves  16 ,  18  are in place, whereupon the D-ring  4  can be released to capture the flanges  20 . 
     The handguard  8  removal/replacement procedure described above can generally be accomplished with only the tool  2  using a one-handed actuation procedure. The effective simplicity of this procedure accommodates operation and firearm servicing under adverse ambient conditions, e.g., in darkness, dampness and in extreme temperatures. 
     III. First Modified or Alternative Embodiment Firearm Spring Compression Tool  102   
       FIGS. 8-13  show a firearm spring compression tool  102  comprising a first modified or alternative aspect of the present invention. The compression tool  102  is configured for compressing a retaining ring  104  to release a handguard  106 . The retaining ring  104  is generally cylindrical, as opposed to the tapered, conical configuration of the D-ring  4  described above. The compression tool  2  is convertible to the spring compression tool  102  and thereby adaptable for compressing the retaining ring  104  by placing an adapter  108  over the yoke arms  34 . The adapter  108  includes lower panels  110 ,  112 , side panels  114  and an opening  116 , which selectively receives the retaining ring  104 . The adapter  108  captures the retaining ring  104  with a flange  118  extending inwardly into the opening  116  and configured for placement over a front end of the retaining ring  104 . 
     With the compression tool  102  installed, the retaining ring  104  compression/decompression and the corresponding handguard  8  removal/placement procedures are similar to those described above in connection with the compression tool  2  and the D-ring  4 . 
     IV. Second Modified or Alternative Embodiment Firearm Spring Compression Tool  202   
       FIGS. 14-18  show a firearm spring compression tool  202  comprising a second modified or alternative embodiment or aspect of the present invention, including an extended base  224 . The extended base  224  has a proximal, magazine well section  226  and a distal, extension section  227 . The longitudinally aligned base sections  226 ,  227  generally extend in opposite directions from a rotational axis for a yoke  228  and an actuator  240 , which are substantially similar in construction and function to the yoke  28  and the actuator  40  described above. 
     The yoke  228  includes a rearwardly-extending bearing hub  252 , which terminates at a bearing surface  254 . The bearing surface  254  includes an upper, sloping bearing surface portion  256 , and a lower, generally flat bearing surface portion  258  configured for accommodating yoke  228  rotation (e.g., counterclockwise, as shown in  FIG. 17 ) whereby the delta ring  4  is depressed for firearm handguard disassembly. The sloping bearing surface portion  258  of the bearing hub  252  facilitates the delta ring compression procedure, substantially as described above in connection with the compression tool  2 . 
     In operation, the second modified firearm spring compression tool  202  can be mounted on a firearm by inserting the base proximate, magazine well section  226  into the firearm magazine well  26 . The base distal extension section  227  is adapted for clamping, e.g., in a bench vise or other clamping tool. Moreover, the extension section  227  can be grasped as a convenient handle by a person servicing the firearm  6 . Compression of the delta ring  4  and removal of the handguard  8  can otherwise proceed as described above. 
     V. Third Modified or Alternative Embodiment Firearm Spring Compression Tool  302   
     A spring compression tool comprising a third modified or alternative embodiment or aspect of the present invention is shown in  FIGS. 19-22  and is generally designated by the reference numeral  302 . The tool  302  includes a modified base  324  with a distal, hollow T-handle  326  in lieu of the extended base  224  described above. The T-handle  326  is configured for being gripped and rotated by an operator. Moreover, the T-handle  326  is generally cylindrical with a coaxial bore  328 , which can receive a cylindrical member or tool for extended leverage as necessary. 
     VI. Conclusion 
     It is to be understood that while certain embodiments and/or aspects of the invention have been shown and described, the invention is not limited thereto and encompasses various other embodiments and aspects. For example, the components of the tools  2 ,  102 ,  202  and  302  are scalable and reconfigurable to accommodate various applications.