Patent Publication Number: US-9891016-B2

Title: Firearm with a hammer mechanism

Description:
FIELD OF THE DISCLOSURE 
     The disclosure relates to a firearm with a hammer mechanism. 
     BACKGROUND 
     This type of firearm is known under the name Sauer 303. It also contains a housing, a barrel fastened to the housing, a bolt assembly for closure of a cartridge chamber provided in the barrel and a hammer mechanism to activate a firing pin arranged in the bolt assembly. The hammer mechanism in this known gas-operated firearm consists of a hammer mounted to rotate on a trigger housing, which acts directly on the firing pin arranged in the bolt assembly. 
     SUMMARY 
     A firearm of the type just mentioned with an alternative hammer mechanism is disclosed. Expedient modifications and advantageous embodiments are also disclosed. 
     In an embodiment, the hammer mechanism in the firearm according to the disclosure has a hammer strut arranged between the firing pin and a cocking piece offset parallel to the firing pin. A connection can be made via this hammer strut between the cocking piece arranged in the housing behind a magazine shaft and the firing pin arranged in the bolt assembly. 
     The hammer strut expediently runs above and along a downwardly open magazine shaft arranged in the housing and in a particularly advantageous embodiment can be guided to move in a longitudinal groove on the inside of a rear part of the barrel parallel to the center line of the barrel. 
     In a preferred embodiment, the hammer strut has a front crosspiece and a rear crosspiece for connection to the firing pin and the cocking piece. The crosspieces expediently protrude inward for contact with the cocking piece and activation of the offset firing pin. 
     A cocking element cooperating with the firing pin and operable by the hammer strut can be arranged on the bolt assembly to activate the firing pin in another advantageous embodiment. The cocking element can be designed in the form of a lever and attached with one end to the rear end of the bolt assembly to pivot about a pin offset laterally relative to the longitudinal axis of the bolt assembly and perpendicular to the longitudinal axis. The other end of the lever-like cocking element can be designed as a free end protruding laterally relative to the bolt assembly for contact with the hammer strut. 
     The cocking element in another advantageous embodiment can be arranged to pivot in a transverse groove on the rear end of the bolt assembly and designed in the form of a wedge with an oblique surface facing the firing pin. 
     The cocking element can be expediently arranged to rotate on a breech lock mount insertable into the housing around a transverse pin between a rear starting position and a front firing position. The cocking piece is acted upon by a cocking spring, which is stretched between the cocking piece and a cocking lever movable by means of a cocking slide between a rear uncocked position and a front cocked position. The cocking spring is therefore only tensioned when the locking lever is moved into a cocked position via the cocking slide. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Additional details and advantages of the disclosure are apparent from the following description of a preferred embodiment example with reference to the drawing. In the drawing: 
         FIG. 1  shows a partial longitudinal section of gas-operated firearm; 
         FIG. 2  shows a breech lock of the gas-operated firearm depicted in  FIG. 1 ; 
         FIG. 3  a partial cutaway perspective view of the rear part of the gas-operated firearm depicted in  FIG. 1  with the breech lock in an unlocked position; 
         FIG. 4  shows a longitudinal section of the rear part of the gas-operated firearm depicted in  FIG. 3  with the breech lock in the unlocked position; 
         FIG. 5  shows a partial cutaway perspective view of the rear part of the gas-operated firearm depicted in  FIG. 1  with the breech lock in the locked position; and 
         FIG. 6  shows a longitudinal section of the rear part of the gas-operated firearm depicted in  FIG. 5  with the breech lock in the locked position. 
     
    
    
     DETAILED DESCRIPTION 
     A partial longitudinal section of a gas-operated firearm is depicted in  FIG. 1  with a receiver or housing  1 , a barrel  2  mounted on housing  1  and a front shaft  3 . A guide rod  4  protruding forward when viewed in the direction of firing and parallel to the center line of barrel  2  is fastened to housing  1 . A bolt-operating device  5  for movement of a bolt  6  depicted in  FIGS. 2 to 6  is guided to move on the guide rod  4  freely protruding forward and not fastened to barrel  2 . A recoil spring  7  is also arranged on the guide rod  4 , via which the bolt-operating device  5  is forced forward. The front shaft  3  with its front end viewed in the direction of firing is fastened on the guide rod  4  via external threads  8  on the front free end of guide rod  4  and a threaded sleeve  9  provided with corresponding internal threads. 
     The bolt-operating device  5  has a carrier  10  guided to move on the guide rod  4  and two push rods  11  fastened to carrier  10 . Each rear free end of the two push rods  11 , viewed in the direction of firing, contains a ramp-like control cam (not shown here), via which the bolt  6 , provided with lateral protrusions  12  and depicted in  FIG. 2 , can be moved between an upper locked position depicted in  FIG. 3  and a lower unlocked position by displacement of the operating device  5 . The bolt-operating device  5  is forced forward, viewed in the direction of firing, via the bolt spring arranged on guide rod  4  and stretched between housing  1  and carrier  10 . In this position, the bolt  6  is forced upwards, so that a locking block  13  protruding upwards from the top on bolt  6  enters into engagement according to  FIG. 3  in a locking groove  14  on barrel  2 . If the bolt-operating device  5 , on the other hand, is pushed rearward, viewed in the firing direction, either via a bolt handle  15  or the gas pressure during firing of a shot against the force of the bolt spring  7 , the bolt  6  can be moved downwardly due to the control cam and the locking block  13  can disengage from the locking groove  14  on barrel  2  for opening of the bolt. 
     It follows from  FIG. 1  that the barrel  2  has a rear part  16  that can be mounted on housing  1  and firmly connected to it and a front part  17  freely protruding from lock housing  1 . The rear part  16  enlarged in diameter relative to front part  17  of the barrel  2  has a front area closed in the peripheral direction and a rear area opened downwardly. A side ejection opening  18  for cartridge ejection is provided in the tunnel-like rear area with the cross section of an annular segment on the rear part  16  of barrel  2 . The rear part  16  and the front part  17  of barrel  2 , when viewed in the direction of firing, are made from a single piece in the depicted embodiment. The two parts  16  and  17  of barrel  2 , however, can also be made as individual parts, connected and firmly joined to each other, for example, by soldering or another appropriate means of connection. 
     Two radially protruding retaining pins  19  are provided on the rear part  16  of barrel  2  lying on housing  1  for fastening of barrel  2  to housing  1 . The retaining pins  19  are provided with external threads and can be radially inserted into the rear part  16  of barrel  2  or directly molded onto the barrel  2 . The retaining pins  19  are designed for engagement in two holes  20  arranged next to each other in a protruding support part  21  of housing  1 . The barrel  2  can be fastened to housing  1  via the two retaining pins  19  with the freely protruding front part  17  through two nuts  22  accessible from the bottom of housing  1 . The rear end of the front shaft  3  is also fastened to the support part  21  of lock housing  1 . A downward protruding gas-discharge block  23  is provided in the middle area of the barrel  2  on front part  17 . 
     As follows from  FIG. 1 , the gas-discharge block  23  has a gas cylinder  24  with a gas-discharge hole  25  opening into barrel  2  and a pressure piston  26  guided to move axially in gas cylinder  24 . The pressure piston  26  contains a piston rod  27  extending through a rear hole in the gas-discharge block  23 , which cooperates with the carrier  10  of the bolt-operating device  5  to move the bolt  6  into the unlocked position. 
     A chamber  28  provided in barrel  2  is closed off downward by the bolt  6  depicted in cross section in  FIGS. 3 and 4 . A firing pin  29  is guided to move axially in the bolt  6 . A firing pin spring  30 , arranged around firing pin  29 , is also accommodated in the bolt  6 , through which the front tip  31  of the firing pin  29  is forced into a retracted position. The rear end  32  of firing pin  29 , viewed in the direction of firing, lies on a lever-like cocking element  34  arranged to pivot in a transverse groove  33  on the rear end of bolt  6 . The lever-like cocking element  34  is connected to the bolt  6  with its one end to pivot about a pin  35  laterally offset relative to the longitudinal axis of the bolt  6  and perpendicular to the longitudinal axis. The free other end  36  of the lever-like cocking element  34  protrudes laterally from the bolt  6  according to  FIG. 2 . 
     A firearm lock with a cocking piece  37  movable between a rear initial position and a front triggering position for activation of the firing pin  29  arranged in bolt  6  via a hammer strut  38  and the lever-like locking element  34  on bolt  6  is shown in  FIG. 2 . A hammer mechanism for operation of the firing pin  29  arranged in the bolt  6  is formed by the cocking piece  37 , the hammer strut  38  and the lever-like cocking element  34 . The hammer strut  38  offset parallel to the center axis of the bolt  6  has a front crosspiece  39  that comes to a stop on its front end with the protruding end  36  with a lever-like cocking element  34  and a rear crosspiece  40  that cooperates with the cocking piece  37 . 
     The cocking piece  37  is mounted to rotate on a lock carrier  41  insertable into housing  1  around a cross pin  42 . A slide stop  43  is also arranged on the lock carrier  41 , via which the cocking piece  37  can be held in the rear initial position or released via a trigger not shown here for firing of a shot. A locking lever  44  is also linked on the lock carrier  41  to pivot about another cross pin  45  between a rear uncocked position and a front cocked position. A cocking spring  46  is stretched between the locking lever  44  and the cocking piece  37 . Displacement of the locking lever  44  between the rear uncocked position and the front cocked position occurs through a cocking slide  47 , which contains a lower part  48  connected to a locking lever  44  and an upper part  49  connected to it. The slide-like upper part  49  operable by the thumb of a shooter is guided according to  FIG. 3  in a recess  50  on the oblique top of a rear end  51  of housing  1  so that the cocking slide  47  can be moved between a lower safe position and an upper off-safe position. 
     It is apparent in  FIG. 3  that the hammer strut  38  is guided to move in the longitudinal grove  52  on the inside of the tunnel-like rear part  16  of the barrel  2  offset laterally and parallel to the firing pin  29  and also the center line of barrel  2 . The front crosspiece  39  and the rear crosspiece  40  of the hammer strut  38  protrude inwardly, so that they can come to a stop with the cocking element  34  in the bolt  6  and the cocking piece  37 . The hammer strut  38  runs above and along a downwardly open magazine shaft  53  arranged in housing  1 , into which a magazine can be inserted. The connection between the cocking piece  37  arranged behind the magazine shaft  53  and the firing pin  29  arranged in bolt  6  can be made via hammer strut  38 . The lever-like cocking element  34  according to  FIG. 4  is designed in the form of wedge with an oblique surface  54  facing the firing pin  29 . 
     The breech lock is shown in an unlocked position in  FIGS. 3 and 4 . The cocking slide  47  is situated in the lower safe position so that the locking lever  44  is also situated in a rear locked position and the main spring  46  is unlocked. In this position of the cocking slide  47  the cocking piece  37  held in the rear starting position cannot be knocked off even during operation of the trigger. 
     Only when the cocking slide  47  is pushed upward into the upper off-safe position depicted in  FIGS. 5 and 6  does the locking lever  44  also enter the front cocked position, so that the main spring  46  is tensioned and the breech lock is therefore in a cocked position. If the trigger is then operated, the cocking piece  37  can reach the depicted front firing position through the force of the tightened main spring  46 , in which case the cocking piece  37  pushes the hammer strut  38  forward (viewed in the direction of firing) and the hammer strut  38  via the lever-like cocking element  34  also forces the firing pin  29  within bolt  6  forward to release a shot against the force of the firing pin spring  30 . 
     When a shot is fired, some of the powder gases are guided into gas cylinder  24  through the gas-discharge hole  25  of barrel  2 . The pressure piston  26  is forced rearward, viewed in the direction of firing, by the gas pressure taken off in gas cylinder  24 . The bolt-operating device  5  with the carrier  10  and the two push rods  11  is then also pushed rearward against the force of recoil spring  7 . The bolt  6  can be moved downwards by the backward movement of the two push rods  11 , so that the locking block  13  is unlocked on barrel  2  and the bolt  6  can open the chamber rearwards in barrel  2 . During backward movement of the bolt  6 , the empty cartridge is ejected via the ejection opening  18  and the breech lock is locked. A new cartridge can then be brought to the level of the chamber via the magazine spring of a magazine (not shown here). The bolt  6  is forced forward by the recoil spring  7  via the bolt-operating device  5  with the carrier  10  and the two push rods  11  and the new cartridge forced into the chamber. The bolt  6  goes back to the locked position and the bolt is closed via the control cam on the push rods  11 . 
     LIST OF REFERENCE NUMBERS 
     
         
         
           
               1  Housing 
               2  Barrel 
               3  Front shaft 
               4  Guide rod 
               5  Bolt-operating device 
               6  Bolt 
               7  Main spring (recoil or bolt spring) 
               8  External threads 
               9  Threaded sleeve 
               10  Carrier 
               11  Push rods 
               12  Protrusions 
               13  Locking block 
               14  Locking groove 
               15  Bolt handle 
               16  Rear part of barrel 
               17  Front part of barrel 
               18  Ejection opening 
               19  Retaining pin 
               20  Holes 
               21  Support part 
               22  Nuts 
               23  Gas-discharge block 
               24  Gas cylinder 
               25  Gas-discharge hole 
               26  Pressure piston 
               27  Piston rod 
               28  Chamber 
               29  Firing pin 
               30  Firing pin spring 
               31  Front end of firing pin 
               32  Rear end of firing pin 
               33  Transverse groove 
               34  Cocking element 
               35  Pin 
               36  Free end of cocking piece 
               37  Cocking piece 
               38  Hammer strut 
               39  Front crosspiece 
               40  Rear crosspiece 
               41  Lock carrier 
               42  Cross pin 
               43  Slide stop 
               44  Locking lever 
               45  Cross pin 
               46  Cocking spring 
               47  Cocking slide 
               48  Lower part 
               49  Upper part 
               50  Recess 
               51  End part 
               52  Longitudinal groove 
               53  Magazine shaft 
               54  Oblique surface