Abstract:
Automatic firearms and safety mechanisms for automatic firearms are disclosed. In an illustrated example, a disclosed firearm includes a breech mounted for movement between a fired position and a cocked position, a breech catch having an inoperative position and a locked position, and a sear arm mounted to the breech catch. The disclosed firearm also includes a safety to permit at least one of the sear arm and the breech catch to move out of a motion path of the breech when the breech moves from the fired position toward the cocked position, but to maintain the sear arm in engagement with the breech when the breech is in the cocked position and the firearm is dropped.

Description:
RELATED APPLICATION  
       [0001]    This patent issues from a continuation which claims priority from International Patent Application Serial No. PCT/EP02/14599 which was filed on Dec. 19, 2002 and is hereby incorporated by reference in its entirety. 
     
    
     
       FIELD OF THE DISCLOSURE  
         [0002]    This disclosure relates generally to firearms, and, more particularly, to safety mechanisms for automatic firearms.  
         BACKGROUND  
         [0003]    When position references such as “above”, “in front” or the like are mentioned in this document, the weapon is assumed to be in normal firing position, firing horizontally “forward” (i.e., away from the shooter).  
           [0004]    U.S. Pat. No. 4,133,128, DE-OS 1 428 772 and EP 0 204 691 A2 are known prior art.  
           [0005]    Automatic weapons, such as machine guns or sub-machine guns, which are only intended for sustained fire have a rather simple trigger mechanism. As used herein, the term “automatic firearm” is intended to encompass all rapid-firing weapons including machine guns and sub-machine guns. A representative example of a prior art trigger mechanism for an automatic firearm is described in the following.  
           [0006]    Beneath the motion path of the breech there is a butt, in which a trigger is swivel-mounted. The swivel axis, which proceeds laterally to the longitudinal axis of the firearm, is located over the trigger, so that, upon operation of the trigger, the rear upper part travels a curved path upward. This rear upper part of the trigger acts on the front end of a breech catch. The breech catch is mounted in the weapon casing or in the butt and can be pivoted around an axis which is also lateral to the longitudinal axis of the firearm. The rear end of the breech catch is constructed as a sear arm. When the trigger is pressed forward to its resting position by a trigger spring, then the front end of the breech catch moves downward, and the sear arm moves upward. This upper position of the sear arm is the locking position.  
           [0007]    The breech catch is usually cushioned by a separate spring, which forces it into the locking position. If the breech is pulled back to its resting position with the breech catch in its locking position, then the breech moves the sear arm and, thus, the rear end of the breech catch downward as it passes at least partially over the sear arm. When a sear catch, which is constructed on the bottom of the breech, has passed over the sear arm, then the sear arm snaps upward and engages the sear catch to hold the breech in its rearward position. The weapon is now cocked and ready to fire.  
           [0008]    When the trigger is operated, then the sear arm sinks until it releases the sear catch and the weapon begins sustained fire. When the trigger is released, then the sear arm and the sear catch move up to hold the breech in its fire readiness position (rear position). As a result, the sustained fire ceases.  
           [0009]    Usually only a safety catch is used as a safety mechanism. While the safety catch rules out unintentional operation of the trigger, it does not rule out a giving way of the sear arm due to, for example, forces of gravity, if the loaded, cocked and trigger-secured machine gun falls off a truck.  
           [0010]    While one could also lock the breech catch for security, such an approach has the disadvantage that the breech gets jammed over the breech catch when it is pulled back with a locked weapon, because the breech catch cannot give way.  
           [0011]    It is proper to put the weapon on safety when an extraordinary situation occurs. An empty magazine or the end of the ammunition belt can be an extraordinary situation for inexperienced shooters if the breech is located in the front position. However, particularly in the case of a jammed loading mechanism, the attention of the shooter may be completely occupied, so that a mistaken operation of operating devices can occur. In the case of a jammed loading mechanism, the breech should, as the first measure, be pulled back so far that the sear arm falls into the sear catch, so that the caught breech does not come loose, run to the front and inadvertently trigger a shot.  
           [0012]    At least in training and at the shooting range, it is also desirable that the breech be pulled back when the safety is on and the firearm not be ready to fire until right before the shot is fired. However, up to now this has only been possible with safety catches.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a partially cut away sectional view of a butt of an automatic firearm and the rear, bottom part of the breech in the front position.  
         [0014]    [0014]FIGS. 2 through 5 are similar to FIG. 1. However, they illustrate the weapon in a locked state as the breech is moved further to the rear from figure to figure. 
     
    
       [0015]    Only in FIG. 1 are all of the drawing reference numerals entered. For reasons of clarity, certain reference numerals have been omitted in FIGS. 2 through 5. However, all of the figures show the same weapon. Therefore, the drawing reference numerals as used in FIG. 1 are valid for all of the figures.  
       DETAILED DESCRIPTION  
       [0016]    A butt  1  of a handheld automatic weapon is shown in the figures. A breech  3  is mounted for movement above the butt  1  such that the breech  3  can be moved horizontally along a center axis  5 . The butt  1  is attached to a casing that defines a motion path for the breech  3 . For simplicity of illustration, the casing is not shown.  
         [0017]    The butt  1  has a trigger guard  7  on the front. A trigger  9  is positioned within the trigger guard  7 . The main part of this trigger  9  is an acute triangle with the apex pointed to the bottom. The triangle is penetrated by a lateral running trigger shaft  11  near the middle of its base. A trigger spring  13  in the form of a spiral-shaped wire spring has two legs. The bottom spring leg  15  forces the trigger  9  forward. The central spiral section of the trigger spring  13  loosely surrounds a cross pin  17 . The upper spring leg  19  of the trigger spring  13  engages a breech catch  21 .  
         [0018]    This breech catch  21  is approximately rectilinear in design and has two lever arms, namely, a front lever arm  23  and a rear lever arm  25 . The upper spring leg  19  of the trigger spring  13  engages the bottom of the rear lever arm  25 . A release roller  27  sits under the center of the front lever arm  23 . This release roller  27  can be pivoted around a lateral axis which is seated in the trigger  9 , to be precise, near the rear part of the base of the trigger  9 . The breech catch  21  is swivel-mounted to a lateral lever axle  29  between the front  23  and the rear lever arm  25 .  
         [0019]    The upper spring leg  19  loads the breech catch  21  in a counter-clockwise direction. The lower spring leg  15  loads the trigger  9  in a clockwise direction. The swivel directions used in this document are referenced to the drawings in which they appear.  
         [0020]    If the trigger  9  is operated, that is, pivoted counter-clockwise against the force of the trigger spring  13 , the release roller  27  lifts the front lever arm  23  against the force of the trigger spring  13  and the end of the rear lever arm  25  is lowered.  
         [0021]    A safety catch  33 , which pivots around a crossbolt  39 , is attached at the rear end of the rear lever arm  25 . A sear arm  37  is constructed behind the crossbolt  39  on the upper side of the safety catch  33 . A nose  41  which extends forward and downward is constructed in front of the crossbolt  39 . A compression spring  35  sits between the bottom side of the rear lever arm  25  and the top side of the nose  41 . The compression spring  35  forces the safety catch  33  upward.  
         [0022]    When the breech catch  21  is in the resting position, the sear arm  37  engages in the motion path of the breech  3 . If the breech  3  is guided to the rear end of its motion path, then a breech-closing spring (not shown in the figures) attempts to return the breech  3  forward to the position that is shown in FIG. 1. The breech  3  has a sear catch  31  constructed on its bottom side. Therefore, when the breech-closing spring moves the breech  3  forward, the sear catch  31  engages the sear arm  37  and thrusts it forward. As the breech  3  moves forward, it forces the safety catch  33  to an end position against the breech catch  21 . The force of the compression spring  3   5  is supported thereby (FIG. 5).  
         [0023]    The front lever arm  23  is bent on its front end and is held in a specified operating position, which is shown in FIG. 1, by a trip-releasing catch  43  positioned underneath. This trip-releasing catch  43  is pivoted around a pin against the force of a catch spring  45 . The catch spring  45  biases the trip-releasing catch  43  in a counterclockwise direction. The pin is near the front part of the base of the trigger  9 , attached within.  
         [0024]    When in the operating position shown in FIG. 1, the free end of the trip-releasing catch  43  extends into the motion path of the breech  3 . As a result, the breech catch  21  is kept in the inoperative position when the trigger  9  is released and the breech  3  is not currently in its rear position. Not until the breech  3  moves toward the rear does it engage the trip-releasing catch  43  and turn it in the clockwise direction (compare FIGS. 2 and 3). When the trip- releasing catch  43  turns in the clockwise direction, it releases the breech catch  21 . As a result, the breech catch  21  turns counterclockwise, so that the sear arm  37  can engage the sear catch  31  of the breech  3  and hold it in the rear position (FIG. 5). Thus, the trip-releasing catch  43  makes controlled firing of shots possible, as though it were absent.  
         [0025]    The trip-releasing catch  43  is, however, also a reason why it is not possible to simply lock the breech catch  21  in the safety-on state by means of a simple so-called “trigger pin safety.” For example, FIG. 1 shows the state of the firearm when the shooter has emptied the ammunition belt with the trigger pulled and then releases the trigger. If only the breech catch  21  were locked by means of a trigger pin safety, then, because the trip-releasing catch  43  holds the breech catch  21  in the position of FIG. 1, one could pull back the breech  3  in the safety on state, but the sear arm  37  could not fall into the sear catch  31  of the breech  3 . The breech  3  would simply run forward again.  
         [0026]    If the trip-releasing catch  43  were not present, then in the position of the breech  3  and the trigger  9  of FIG. 1, the front lever arm  23  would rest on the release roller  27  of the trigger  9 . If the breech catch  21  were then locked by means of a trigger pin safety, then the breech  3  could be pulled back, because the safety catch  33  would give way to the force of the compression spring  35  and let the breech pass to the rear. The trigger  9  would still be movable. The shooter, thus, could not determine whether the safety was on or off by lightly activating the trigger (the so-called “taking up the slack of the trigger”).  
         [0027]    In the following, the manner in which the illustrated trigger device locks both the breech catch  21  and the trigger  9  in the safety-on state is demonstrated.  
         [0028]    The butt  1  is penetrated in the rear, upper part by a lateral pivoting safety roller  47 . A safety-operation lever sits on an end of this safety roller  47  on the exterior of the butt  1 . (Alternatively, two safety levers may be used, one safety lever positioned on each end of the safety roller  47 .) The safety-operation lever (which is shown in the figures in dotted lines), is preferably positioned to be easy to reach with the thumb of the hand activating the trigger. Thus, if one lever is used, it should be positioned on the side of the firearm that corresponds to the shooting hand preference of the shooter.  
         [0029]    The safety roller  47  has two defined positions, namely, the firing position and the safety position. The firing position is shown in FIG. 1. The safety position is shown in FIGS. 2 through 5.  
         [0030]    The safety roller  47  has two recesses at its outer periphery, namely, a safety catch recess  49  and a safety bolt recess  51 . Further a horizontal safety bolt  53  is attached in the butt  1  between the trigger  9  and the safety roller  47 . The horizontal safety bolt  53  may be moved horizontally to the rear against the force of a safety spring (not shown). The end of the safety bolt  53  facing the safety roller  47  is a stop head constructed in the shape of a truncated cone. When the safety roller  47  is in the firing position, the stop head of the safety bolt  53  falls into the safety bolt recess  51  (FIG. 1) to reliably hold the safety roller  47  in the firing position. When the safety roller  47  is in the safety position (FIGS. 2-5), the apex of the stop head of the safety bolt  53  falls into a small depression in the outer surface of the safety roller  47 . This depression cannot be seen in the drawings, but is located between the two recesses  49  and  51 .  
         [0031]    The safety spring is located in a pocket bore of the butt  1 . The bottom of this pocket bore is formed by a wall  70  in the inside of the butt  1 . The trigger  9  has a spur-shaped extension  55 , which extends from the middle of its rear triangle corner to the rear and above. When the trigger  9  is operated, the free end of this extension  55  moves past the wall  70 .  
         [0032]    The safety bolt  53  penetrates the pocket bore and pierces through its floor  70  (i.e., the aforementioned wall  70 ). In the firing position, in which the safety bolt  53  falls into the deep safety bolt recess  51  of the safety roller  47 , the front end of the safety bolt  53  terminates about at the surface of the wall  70  facing the trigger  9  (FIG. 1). The trigger  9  can thus be pulled without hindrance.  
         [0033]    If the safety roller  47  is moved to the safety position (FIGS. 2-5), then the safety bolt  53  is forced out of the safety bolt recess  51  (i.e. forward; to the left in the figures). The front end of the safety bolt  53  then lies in the swivel path of the extension  55  of the trigger  9 . Therefore, the trigger  9  cannot be operated; or at least the trigger cannot be pulled to the full extent of the trigger slack.  
         [0034]    If the trigger device is in the position of FIG. 1, then the breech catch  21  is swiveled by means of the trip-releasing catch  43  into an end position, in which the nose  41  of the safety catch  33  runs into the one side wall of the wedge-shaped safety catch recess  49 . By turning the safety roller  47  counterclockwise into the safety position, the safety catch recess  49  encompasses the nose  41 .  
         [0035]    If the breech  3  is now pulled back (FIG. 3), then the trip-releasing catch  43  is turned clockwise and releases the breech catch  21 . The rear lever arm  25  then moves in an upward direction and the breech catch  21  snaps counterclockwise under the effect of the powerful trigger spring  13 . In the process, the edge of the nose  41  strikes the other side wall of the safety catch recess  49 . The impact of the nose  41  on the side wall of the safety catch recess  49  turns the entire safety catch  33  clockwise against the relatively weak force of the compression spring  35  such that the nose  41  gives way and runs over the edge of the safety catch recess  49  toward the top (see FIG. 4).  
         [0036]    When the sear catch  31  is above the sear arm  37 , then the sear arm  37  falls into the sear catch  31  and the nose  41  pivots over the safety roller  47  (FIG. 5). If the weapon now, for example, falls off a truck to the ground and forces of gravity attempt to swivel the breech catch  21 , then the lower area of the nose  41  will collide with the periphery of the safety roller  47 . As a result, swivel movement of the safety catch  33  is prevented and the safety catch  33  is locked.  
         [0037]    If the safety roller  47  is swiveled back into the firing position, then the trigger  9  and the safety catch  33  are again simultaneously released.  
         [0038]    This is how a trigger device with optimum safety and the highest operating convenience is created.  
         [0039]    From the foregoing, persons of ordinary skill in the art will appreciate that a firearm has been provided wherein it is possible to put the safety on without the forces of gravity being able to bring the breech catch  21  out of engagement with the breech  3 . However, it should always be possible to pull back the breech  3 . In other words, while the breech catch  21  is not movable in response to forces of gravity, it is be able to give way to the pulled back breech  3 .  
         [0040]    To this end, a rapid-firing portable firearm is provided with a trigger device including a trigger  9  that can be pivoted against the force of a spring  13  from a resting position to a fire position. The trigger  9  acts on a swiveling breech catch  21 . The breech catch  21  has a sear arm  37  which may be positioned in the motion path of the breech  3 . The firearm is further provided with a safety catch mechanism that preferably locks the trigger  9  in its resting position. The sear arm  37  is located on a safety catch  33 . The safety catch  33  is swivel-mounted to the breech catch  21 . The safety catch  33  may be moved against the force of a spring  35  from a locking position to an inoperative position. In the inoperative position, the safety catch  33  is not in the motion path of the breech  3 . The safety catch  33  can be forced into its locking position by the breech  3 . The safety catch mechanism ( 47 - 55 ) is also set up to lock the breech catch  21 . A spring-mounted trip-releasing catch  43  is attached to the trigger ( 9 ). In its resting position, the trip-releasing catch  43  does not permit the breech catch  21  to move into its operative position until the breech  3  moves backward.  
         [0041]    The catch  21  has low mass. As a result, the forces of gravity, which become operative in a fall, are lower than the elastic force of the spring  15  which loads the catch  21 . In addition, the breech-closing spring forces the breech  3  into engagement with the catch  21 , thereby holding the catch  31  in the locking position.  
         [0042]    It is possible for the trigger  9  to act exclusively on the breech catch  21 . If the trigger  9  is released only a little while the machine gun is firing, then the breech  3  strikes the edge of the sear arm  37  after its recoil. As a result, the safety catch  33  is forced out of the motion path of the breech  3 . The precise firing of a single shot or short burst of fire is not possible, because one always has to take into account the possibility that one or two unintended shots will follow.  
         [0043]    This problem can be alleviated by means of appropriate training by teaching the soldiers to release the trigger very quickly. However, this is not an acceptable solution. Instead, the illustrated safety catch mechanism addresses this problem by providing a movable edge  47  in the motion path of the safety catch  33 . The safety catch  33  and its spring  35  are constructed such that, upon release of the breech catch  21 , the safety catch  33  may move past the edge  47 , and, in the operative position of the breech catch  21 , the edge  47  locks the breech catch  21  and the safety catch  33 .  
         [0044]    When the trigger is in the released position shown in FIG. 1, the trip-releasing catch  43  keeps the breech catch  21  in an inoperative position until the breech  3  moves back a distance sufficient to operate the catch  43 . When the breech  3  pivots the trip-releasing catch  43 , the catch  43  releases the breech catch  21 . The breech catch  21  responds by snapping into its operative position. Since the spring of the breech catch  21  is stronger than the spring  35  of the safety catch  33 , the safety catch  33  gives way to the breech  3 , so that, upon attempting to move forward to fire a shot, the breech  3  can fall into the sear catch  37 .  
         [0045]    The safety catch  33  is swivel-mounted. This mounting takes place at a lateral axis which penetrates the safety catch  33 . This lateral axis is mounted on the breech catch  21 . When the sear arm  37  gives way to the breech  3  in a counter-clockwise motion, the other end of the safety catch  33  also gives way in a counter-clockwise motion. In the process, the other end of the safety catch emerges under an edge of the safety roller  47 . Since the breech catch  21  continues to swing upward under the influence of the spring  15 , the safety catch  33  is lifted and swings back above the edge of the safety roller  47 , again when the sear arm  37  falls into the sear catch  31 . The breech  3  then forces the safety catch  33  firmly against the breech catch  21 , since the direction of the force acting upon the sear arm  37  runs above the swivel axis of the breech catch  21  and above the swivel axis of the safety catch  33  and, thus, both elements are turned in the same direction (i.e., toward the breech  3 ).  
         [0046]    When a force of gravity acts on the breech catch  21  and endeavors to move it against the elastic spring force  15 , then the safety catch  33  moves along with it and strikes the safety roller  47  with its bottom side (on the same side of the lateral axis as the sear arm  37 ). The breech catch  21  is, thus, not directly locked, but rather indirectly locked by the safety roller  47 .  
         [0047]    A backward motion of the breech  3  is, on the other hand, possible, since in response to such backward motion, the safety catch  33  simply swings down. In the process, the safety roller  47  is arranged such that the swinging down of the safety catch  33  is just barely possible. The arrangement and development of the breech catch  21 , the safety catch  33 , and the safety roller  47 , must therefore occur rather precisely with regard to the butt  1 . However, this is easily possible without any hand finishing being necessary, since rather few tolerances add up.  
         [0048]    The safety catch mechanism could basically be any conventional type of safety catch, (e.g. a sliding safety catch or a push-button safety catch). However, it is particularly advantageous to implement the safety catch mechanism as a lateral running, rotating safety roller  47  in which a recess  49  is constructed whose side wall, together with the circumference of the safety roller  47 , forms the edge which engages the safety catch  33  as mentioned above. Such a safety roller  47  has the advantage of laterally penetrating the butt  1 , so that an operating handle or safety lever can be attached on either or both of the roller&#39;s ends outside of the butt  1 . This right or left safety lever has in each case the same allocation to the trigger  9  and can, thus, be used in the same manner, both for right-handers and left-handers.  
         [0049]    Advantageously, the safety roller  47  may include a stop recess  51 . A safety bolt  53  is also provided, which, in the firing position of the safety roller  47  falls into the stop recess  51 . The safety bolt  53  engages in the motion path of the trigger  9  to lock the trigger  9  when the safety roller  47  is located in the locking position and the safety bolt  53  is not, therefore, engaging in the stop recess. Thus, in the illustrated example, a trigger lock is integrated in the safety catch mechanism. Persons of ordinary skill in the art will appreciate that this integration is not only possible with a safety roller  47 , but is also possible with different types of safety catches. In locking an automatic firearm, it is required that the safety catch  33  be locked by a powerful stop if the weapon is exposed to severe vibrations during sustained fire. In other words, it is necessary to prevent the weapon from inadvertently locking during the firing.  
         [0050]    In the illustrated example, the powerful stop is implemented as a safety catch  33  which automatically engages when and for as long as the safety roller  47  is moved to the safety position. For this purpose, an extension  55  is provided on the trigger  9  which, when the trigger  9  is operated, enters into the motion path of the safety bolt  53 . Since the trigger  9  is usually manufactured as a die cast part or a precision cast part, this extension  55  can be manufactured without any additional costs.  
         [0051]    A stop recess  51  is also provided in the safety roller  47 . The safety bolt  53  falls into this recess  51  as a stop bolt when the weapon is on safety, as is common practice. One or more firing position recesses are also provided. When the safety bolt  53  secures the safety roller  47  in a firing position, rotational motion of the safety roller  47  is restricted in every direction. These firing position recessess can alternatively be constructed on the exterior of the butt  1  and can interact with the operating levers of the safety roller  47 .  
         [0052]    Although certain example methods and apparatus have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.