Patent Publication Number: US-7219461-B1

Title: Bolt assembly with locking system

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present patent application is a continuation of U.S. patent application Ser. No. 10/851,491, filed May 21, 2004, now U.S. Pat. No. 7,107,715 B2, which application claims the benefit of U.S. Provisional Application Ser. No. 60/473,277 entitled “Dual Lug Rotary Lockup” filed May 23, 2003, both applications being hereby specifically incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to firearms, and in particular to a bolt assembly with a locking system for use in a repeating firearm. 
     BACKGROUND OF THE INVENTION 
     Most repeating firearms generally utilize a “rotary lock-up” bolt locking system in which a locking member rotates about a centerline of the barrel assembly, engaging and disengaging tabs or lugs with mating surfaces in the barrel assembly. The tabs, or lugs, traditionally have been integral components of the bolt head and are required to support the rearward axial load produced by the shell or cartridge when fired. As a result of this integral design, the entire bolt head assembly is required to rotate to engage and disengage the lugs. Firearms further must incorporate an extractor to pull the shell or cartridge out of the chamber when the bolt is opened, which extractor typically is mechanically attached the bolt head so as to rotate as an integral component of the bolt head assembly. 
     In the case of shotguns, the extractor is an appendage that extends beyond the face of the bolt head and as a result requires axial and radial clearances be formed in the barrel to accommodate such movement. Machining such radial clearances in the barrel has been and continues to be a difficult operation in the manufacture of rotary lockup barrel assemblies. Typical centerfire rotary lock up bolt assemblies therefore have recessed the extractor within the bounds of the bolt head to eliminate the requirement for axial or radial clearances in the barrel. In either case, the extractor engages the rim of the shell when the firearm is locked up and upon rotation of the bolt head from unlocked to locked or from locked to unlocked, the extractor must slide along the outside diameter surface of the shell or cartridge. Depending on the mechanical interface of the extractor and rim of the shell or barrel, significant malfunctions accordingly can occur. Ideally, the extractor engages the rim of the shell upon close up of the firearm and should remain stationary relative to the cartridge through the entire extraction process, thus reducing the potential for extraction malfunctions and as well as significantly reducing the difficulties in the manufacture of barrels with such axial and/or radial clearance for extractors. 
     Accordingly, it can be seen that a need exists for a bolt assembly and locking system for firearms that addresses the foregoing and other related and unrelated problems in the art. 
     SUMMARY 
     Briefly described, the present invention generally relates to a bolt assembly and locking system for firearms including long guns such as rifles and shotguns, although the principles of the present invention could be applied to other types of firearms including handguns and other firearms, for use in the extraction of a spent cartridge or shell and loading of a live round of ammunition within the chamber of the firearm. In general, the bolt assembly with locking system of the present invention will include a housing or bolt slide having an internal chamber or passage in which a rotary locking lug or member and bolt are received. The rotary locking lug or member includes a cylindrical body portion that is received and is movable along the passage of the bolt slide, and a forward locking ring or section attached to the body. One or more helical slots are formed in the body of the rotary locking lug behind the locking ring, with the rotary locking member being designed to rotate with respect to the bolt slide and bolt as it is translated and moved longitudinally along the passage of the bolt slide. The rotary locking lug further includes a longitudinally extending passage or channel through the locking ring and body thereof. 
     The bolt includes a cylindrical bolt body adapted to be received and be movable longitudinally through the passage of the bolt slide, and a bolt head attached to a first or forward end of the bolt body. An extractor typically is attached to the bolt head for engaging and extracting a spent cartridge or shell during operation of the locking system of the present invention upon firing of a round of ammunition. A firing pin passage or channel further is formed through the bolt and bolt head, in which a firing pin for the firearm is received and can slide so as to engage or contact a round of ammunition for firing the round. A longitudinal slot generally is formed along the upper portion of the bolt body so as to at least partially coincide with the helical slot formed in an upper portion of the rotary locking lug as the bolt translates through the rotary locking lug. 
     A cam member or assembly, which can include one or more cam pins, is received through the bolt slide so as to engage the helical slot(s) of the rotary locking member/lug and the longitudinally extending slot of the bolt. Engagement of the cam member with the longitudinal slot of the bolt prevents the bolt from twisting or rotating with respect to the bolt slide while enabling the longitudinal or translational movement of the bolt along the passage of the bolt slide during operation of the system of the present invention. At the same time, the engagement of the cam member in the helical slot of the rotary locking lug causes the rotary locking lug to be rotated with respect to the bolt head during movement of the bolt and rotary locking lug along the passage of the bolt slide while the bolt head remains generally fixed against substantial rotation. 
     In operation, as a round of ammunition is discharged and the action sleeve assembly of the firearm is driven rearwardly, carrying the bolt slide rearwardly while the cam member contained therewithin engages the helical slot(s) of the locking ring so as to cause the rotation thereof while the bolt head remains fixed against rotation as the bolt slide moves therealong. As the complete bolt assembly translates rearwardly, the extractor will engage the rim of the spent or fired shell or cartridge and pull the cartridge from the chamber until it contacts ejection surfaces of the carrier of the firearm at which time the cartridge is ejected from the firearm. As a next live round is fed from the magazine, the bolt slide is released and moves forwardly until the round is fully seated within the chamber of the firearm stopping the forward motion of the bolt head and rotary locking lug. 
     Various objects, features, and advantages of the present invention will become apparent to those skilled in the art when taken upon review of the following specification, when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a firearm and the bolt assembly and the locking system of the present invention. 
         FIG. 2A  is a perspective view of the action sleeve and bolt assembly of a firearm. 
         FIG. 2B  is an exploded perspective illustration of the bolt assembly and locking system of the present invention. 
         FIG. 3  is a perspective view of the bolt assembly and locking system of the present invention. 
         FIGS. 4A and 4B  are perspective views of the bolt, locking member and bolt slide of the present invention. 
         FIGS. 5A and 5B  are side elevational views, taken in partial cross-section, of the bolt assembly with locking system of the present invention. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     To accomplish a consistent interface between the extractor and a shell or cartridge, the extractor should not rotate, which in turns requires that rotation of the bolt head should be limited as well. Therefore, the present invention is directed to a bolt assembly and locking system  10  for firearms F, that is designed to maintain the extractor alignment with respect to a cartridge or shell to be extracted while still providing a rotating locking lug for engagement with the barrel, with the bolt head/extractor unit generally being substantially mounted/fixed against rotation.  FIGS. 1–5B  show the components of the bolt assembly  10  according to one example embodiment of the present invention. As shown in  FIG. 1 , the bolt assembly  10  can be used with various types of firearms, such as an auto-loading shotgun and other types of long guns, having a receiver  11  in which the bolt assembly  10  is mounted, a barrel  12 , having a chamber  13  defined therein, stock  14 , a fire control or trigger assembly  16 , an action sleeve assembly  17  ( FIG. 2B ) on which the bolt assembly is carried, and a carrier  18  ( FIG. 2A ), for loading a cartridge or round of ammunition  19 . It will further be understood that the principles of the present invention can be applied to other types of firearms, including hand guns. 
     As shown in  FIGS. 2A–3 , the bolt assembly  10  with the locking system of the present invention generally includes a bolt slide  25  or housing, typically formed from a high strength metal material such as steel, which includes a first, rearward or distal end  26  and a second, forward or proximal end  27  with a central passage or counter bore  28  extending therethrough from the forward or proximal end  27  toward the rear end  26 . The bolt slide generally is mounted on the action sleeve assembly so as to be moved or translated through the receiver with the movement of the action sleeve assembly upon firing of a round of ammunition. As shown in  FIG. 2A , the carrier  18  generally is pivotally attached to the receiver and includes a pair of longitudinally extending arms or tabs  29  adapted to engage the round of ammunition  18  for loading the round through the receiver and into the chamber of the firearm. A carrier support  31  is pivotally attached to a side surface of the bolt slide  25  by pivot pin  32 , as indicated in  FIG. 2B , and generally is biased by a spring member  33  into a lowered, resting position. 
     As shown in  FIGS. 2B–5B , a rotary locking member or locking lug  36  is slidably received within the passage or channel  28  of the bolt slide. The locking lug is rotatable about a longitudinal axis, shown at phantom lines  37  in  FIG. 2B , with respect to the bolt slide, and includes a substantially cylindrical body portion  38  defining a central passage or channel  39 . The locking lug further includes a locking ring  41  mounted to a forward portion thereof. The locking ring  41  generally is a plate that is formed with or mounted to the body portion  38  and includes lug or cam surfaces  42  about its peripheral edge for engaging in rotating the arms  29  ( FIG. 2A ) of the carrier  18  to a raised position for engaging and extracting the spent or fired cartridge of the round of ammunition  19  from the chamber. In addition, at least one helical slot  43  is formed through the body portion  38 , extending about the body portion from the rear end thereof toward the locking ring in a spiral or helical configuration. One or more helical slots can be used, typically with one extending across an upper portion of the body along the side to a point along the lower portion of the body as indicated in  FIG. 2B . 
     As shown in  FIGS. 2B ,  3 , and  5 A– 5 B, a bolt  46  is slidably received through the channel  39  of the locking lug and the bolt slide passage or bore  28 . The bolt  46  generally is formed from a metal such as steel and includes a rearwardly extending body portion  47  with a bolt head  48  attached to a forward or front portion of the body and defining a bolt face  49 . At least one longitudinal slot  51  is formed in the bolt body  47  ( FIG. 2B ), typically extending along an upper portion thereof and will be aligned or will coincide with the at least one helical slot  43  formed in the locking lug  36 . An extractor  55  is mounted to the bolt face  49  by a pivot pin  56 , and typically is biased to a raised, engaging position by a spring  57  to engage the rim of a cartridge or shell within the chamber of the firearm in a locking engagement for extraction of the cartridge. 
     As further indicated in FIGS.  2 B and  5 A– 5 B, a firing pin  60  having a rear end  61  and a forward end or tip  62  is received through the bolt slide, locking lug and bolt, extending through the passages of the bolt slide and locking lug and through a firing pin bore or passage  63  formed through the bolt  46 . Additionally, a linkage  64  is pivotally attached to the rear end  26  of the bolt slide  25  to help control the sliding or translational movement of the bolt assembly  10  during extraction and loading of a spent shell/live round of ammunition after firing. 
     As further indicated in  FIGS. 2B and 5A  and  5 B, a cam member or assembly  70  is provided for engaging and causing rotation of the rotary locking lug  36 . In one embodiment illustrated in the drawings, the cam member  70  generally comprises a pair of cam pins  71  and  72  that are received within a vertical passage  73  ( FIGS. 5A and 5B ) formed through the bolt slide  25  and project into the bore or passage  28  of the bolt slide so as to engage the locking lug and bolt. It will also be understood that while a pair of cam pins are shown, it is also possible to use a single cam pin or rod as well. The upper cam pin  71  further is shown with a transverse bore  74  ( FIG. 2B ) formed therein, through which the firing pin  60  is received and guided along its longitudinal movement through the bolt assembly. The cam pins engage the helical and longitudinal slots  43  and  51  of the locking lug  36  and bolt  46 , respectively, so as to cause the rotation of the locking ring  41  of the locking lug, while maintaining the bolt and bolt head, and thus the extractor, in a position substantially fixed against rotation with respect to the cartridge or shell within the chamber during an extraction and loading operation of the bolt assembly of the present invention. 
     As indicated in  FIGS. 4A–4B , the locking lug  36 /locking ring  41  slide along and rotate about the shaft of the bolt  46 , with both of these components, being received within and moveable along the counter bore or passage  28  of the bolt slide  25 . The longitudinal slot  51  ( FIG. 4A ) and helical slot(s)  43  of the bolt and locking lug  38 , respectively, mate with the cam pin or pins  71 / 72 , which are supported within the passage  28  of the bolt slide.  FIGS. 4A and 5A  show the bolt assembly in the “unlocked” mode, that is, the bolt  46  is fully extended from the bolt slide  25 , limited by contact with the cam pins  71 / 72 . The locking lug  36  is also fully extended as well, with the locking ring  41  against the bolt head and its lug or cam surfaces  42  oriented in the vertical plane.  FIG. 4B  shows the bolt assembly in the “locked up” mode, that is, the bolt head and locking ring are fully seated within and against the front end face  27  of the bolt slide. As it is moved to its locked position as shown in  FIG. 4B , the locking ring is rotated such that its lug or cam surfaces will engage mating pockets within the barrel assembly and will urge the carrier to a raised position to eject the spent or fired round or cartridge from the chamber. 
     As the bolt assembly then translates within the firearm towards the shell or cartridge, the bolt head and locking ring remain in the unlocked position until the shell or cartridge is firmly seated within the chamber of the firearm. At that point, as the shell or cartridge becomes fully seated in the chamber, the bolt head and locking ring cease their forward, longitudinal movement. The bolt slide  25 , however, continues to translate forward, with its cam pin(s) engaging and moving ( FIG. 2B ) along the slots  51  and  43  of the bolt and locking lug, respectively. Due to the helical configuration of the slot(s) of the locking lug, the axial translation of the bolt slide/cam pins causes the locking ring to be rotated about the bolt head into its locked position as shown in  FIGS. 2A ,  4 B and  5 . The axial translation or movement of the bolt slide thereafter stops when the locking ring is fully rotated and seated against the bolt slide. 
     In operation of the bolt assembly  10  of the present invention, as indicated in  FIGS. 3–5B , as the trigger of the firearm is squeezed, it releases the hammer of the firearm, which in turn impacts or strikes the firing pin. Upon impact, the firing pin  60  translates forwardly so as to strike the primer of the round of ammunition loaded within the chamber, causing the round to fire. The shot column generated from the fired round of ammunition progresses down the bore of the barrel of the firearm, due to gas pressure from the burning powder, with a portion of the gases generated thereby being redirected rearwardly through ports in the barrel so as to drive the action sleeve assembly  17  ( FIG. 2B ) on which the bolt slide  25  of the bolt assembly  10  with locking system of the present invention is mounted. As the bolt slide is thus carried or translates rearwardly through the receiver of the firearm, the cam pins  71  and  72  ( FIGS. 5A and 5B ) engage and slide along the helical slot or slots  43  of the locking lug, while at the same time moving longitudinally along the longitudinal slot  51  of the bolt  46 . As a result of the engagement of the cam pins within the longitudinal and helical slot(s) of the bolt and locking lug, respectively, the locking ring is caused to rotate counterclockwise, while the bolt head is restricted from rotating. The locking ring will be rotated until the cam pins meet the ends of the helical slot(s) of the locking lug. 
     Upon completion of the locking ring rotation, the cam pins  71  and  72  generally will be at the rear end of the mating slots  43  and  51  of the locking lug and bolt, respectively, and thus further rearward translation or movement of the bolt slide will impart a rearward movement to the locking ring and bolt head. As the complete bolt assembly  10  is translated rearwardly, the extractor  55  engages the rim of the fired shell or cartridge and pulls the shell from the chamber of the firearm. The spent shell or cartridge and the bolt assembly continue moving rearwardly until the rim of the shell contacts the ejection surfaces of the arms or prongs of the carrier, at which time the spent shell is forced to rotate downwardly and is ejected out of the receiver of the firearm, while the bolt assembly continues to move rearwardly so as to engage the carrier, wherein it imparts a clockwise rotation to the carrier to position the carrier prongs downwardly below the magazine so as to receive a next live round of ammunition from the magazine. 
     The bolt slide continues its rearward movement until contact is made between the rear end or face  26  of the bolt slide and the inside face of the firearm receiver. As the next live round of ammunition is released from the magazine, it typically is urged rearwardly due to the magazine spring force and contacts a bolt stop release button on the front of the trigger plate of the firearm fire control, in response to which the bolt slide is released and begins a forward movement through the receiver. As the bolt slide moves forwardly, mating surfaces of the bolt slide and carrier cause the carrier to be rotated counterclockwise so as to raise and align the live round of ammunition with the chamber, with the entire bolt assembly continuing forwardly until the round is fully seated within the chamber of the firearm, which stops the forward motion of the bolt head and locking ring. The bolt slide further continues forwardly with its cam pins  71  and  72  engaging the helical slot(s) of the locking lug so as to cause the locking ring to be rotated in a clockwise direction as indicated in  FIG. 4B , with the prongs or arms of the carrier being positioned above the bolt slide as indicated in  FIG. 2A . 
     It will be further understood by those skilled in the art that while the foregoing has been disclosed above with respect to preferred embodiments or features, various additions, changes, and modifications can be made to the foregoing invention without departing from the spirit and scope of thereof.