Abstract:
A passive safety mechanism which blocks the firing element until the trigger is deliberately pulled. A link which connects the trigger to the blocking piece serves a dual function by also connecting the trigger to the triggerbar and providing a pivot for the triggerbar. If the link is removed the triggerbar is disconnected from the trigger and the trigger is disconnected from the gun. The blocking piece also serves multiple functions by aligning the triggerbar and positioning the trigger return spring. If the blocking piece is removed the trigger return spring is disengaged.

Description:
BACKGROUND  
         [0001]    1. Field of Invention  
           [0002]    This invention relates to firearms, specifically to the passive safety mechanism of a handgun.  
           [0003]    2. Description of Prior Art  
           [0004]    Passive safety mechanisms designed to prevent firing until the trigger is deliberately pulled have long been known in the art. Such safety mechanisms typically incorporate a spring-loaded member which blocks the path of the firing element. Heretofore known passive safety mechanisms suffer from a number of disadvantages:  
           [0005]    (a) Such safety mechanisms are easy to disable because they are incidental to the basic mechanism of the firearm. Such safety mechanisms may be disabled by the simple removal of components without otherwise adversely affecting the normal functioning of the firearm.  
           [0006]    (b) In the event such safety mechanisms are disabled by the absence of components, this condition may not be readily evident from an external examination of the firearm.  
           [0007]    (c) The dedicated springs incorporated in such safety mechanisms are subject to loss during disassembly and failure in service.  
           [0008]    (d) Such safety mechanisms increase manufacturing costs due to the requirement of a dedicated surface on the firing element.  
         OBJECTS AND ADVANTAGES  
         [0009]    Accordingly, among the objects and advantages of the present invention are:  
           [0010]    (a) to provide a passive safety mechanism which precludes normal operation of the firearm when components of the safety mechanism are absent.  
           [0011]    (b) to provide a passive safety mechanism which shows external evidence that safety components are absent.  
           [0012]    (c) to provide a passive safety mechanism which is resistant to improper assembly.  
           [0013]    (d) to provide a passive safety mechanism which consists of a minimum of parts and does not require a dedicated spring.  
           [0014]    (e) to provide a passive safety mechanism which does not require a dedicated surface on the firing element.  
           [0015]    Further objects and advantages will become apparent from consideration of the following description and drawings.  
       
    
    
     DRAWING FIGURES  
       [0016]    [0016]FIG. 1 is a right side view of a single shot pistol incorporating the invention.  
         [0017]    [0017]FIG. 2 is a partial sectional right side view of the frame showing the blocking piece engaged.  
         [0018]    [0018]FIG. 3 is a partial sectional right side view of the frame showing the blocking piece disengaged and the firing element positioned fully rearward.  
         [0019]    [0019]FIG. 4 is a partial sectional right side view of the frame showing the blocking piece disengaged and the firing element positioned fully forward.  
         [0020]    [0020]FIG. 5 is a partial sectional left side view of the frame showing the blocking piece engaged.  
         [0021]    [0021]FIG. 6 is a partial sectional left side view of the frame showing the blocking piece disengaged and the firing element positioned fully rearward.  
         [0022]    [0022]FIG. 7 is an isometric view of the link.  
         [0023]    [0023]FIG. 8 is an isometric view of the blocking piece.  
         [0024]    [0024]FIG. 9 is a left side view of the blocking piece.  
         [0025]    [0025]FIG. 10 is an isometric view of the trigger.  
         [0026]    [0026]FIG. 11 is an isometric view of the triggerbar.  
         [0027]    [0027]FIG. 12 is an left side view of the triggerbar and trigger return spring.  
         [0028]    [0028]FIG. 13 is an exploded view of the trigger, triggerbar, link, and blocking piece.  
         [0029]    [0029]FIG. 14 is a top view of the trigger, triggerbar, link, blocking piece, and trigger return spring.  
         [0030]    [0030]FIG. 15 is a top view of the trigger, triggerbar, link, blocking piece, and trigger return spring with the trigger pulled fully rearward.  
         [0031]    [0031]FIG. 16 is a left side view of the frame.  
         [0032]    [0032]FIG. 17 is a left side view of the frame and blocking piece.  
         [0033]    [0033]FIG. 18 is a rear view of the frame and blocking piece.  
     
    
       [0034]    [0034]                                         Reference Numerals in the Drawings                                10   Single shot pistol       12   Right grip plate       14   Barrel       16   Hinge pin       18   Frame       20   Trigger       22   Triggerbar       24   Trigger return spring       26   Sear       28   Firing element       30   Sear catch       32   Driving Spring       33   Guide       34   Blocking piece       35   Vertical projection of blocking piece       36   Recess       38   Surface       40   Backstrap       42   Upper cross pin       43   Lower cross pin       44   Transverse projection of blocking piece       46   Mandrel       48   Stop pin       50   Link       52   Cam Track       54   Horizontal segment of cam track       56   Inclined segment of cam track       58   Camming stud of link       60   Connecting arm of link       62   Trigger hole       64   Triggerbar hole       66   Spring seat of trigger       68   Bearing surface of triggerbar       70   Assembly of 20, 22, 24, 34, and 50       72   Slot       74   Window       76   Opening                    
       DESCRIPTION  
       [0035]    FIGS.  1  to 18  
         [0036]    [0036]FIG. 1 shows a single shot pistol  10  which incorporates the invention. Pistol  10  has a barrel  14 , a frame  18 , and a trigger  20 . FIG. 1 also shows a right grip plate  12 . Barrel  14  is pivotally mounted to frame  18  via a hinge pin  16 .  
         [0037]    [0037]FIG. 2 shows a triggerbar  22  which is pivotably connected to trigger  20 . Trigger  20  is longitudinally slidable and is maintained in battery position by a trigger return spring  24 . Trigger return spring  24  is a left hand wound  90  degree torsion spring and is located within a recess  36  in frame  18 . Trigger return spring  24  is mounted on a cross pin mandrel  46  and is constrained from rotation by a stop pin  48 . Trigger return spring  24  bears upon triggerbar  22  and serves to place a forward bias on both trigger  20  and triggerbar  22 . Trigger return spring  24  also has a vertical component of force which urges the free end of triggerbar  22  upward into the battery position. Triggerbar  22  has an integral sear  26  which engages a firing element  28  via a sear catch  30 . A similar firing element is disclosed in U.S. patent application titled “Firing Mechanism” filed Oct. 31, 1997 which is hereby incorporated by reference in its entirety herein. Firing element  28  has a driving spring  32  mounted on a guide  33 . Inadvertant forward motion of firing element  28  is prevented by a blocking piece  34  having a vertical projection  35  which impedes the forward path of sear catch  30 . Blocking piece  34  is vertically slidable within recess  36 . Blocking piece  34  is substantially the same longitudinal length as the available space in recess  36 . Longitudinal translation of blocking piece  34  is constrained by a surface  38  and a removable backstrap  40 . Backstrap  40  aligns and guides blocking piece  34  and is retained by an upper cross pin  42  and a lower cross pin  43 . Removal of backstrap  40  allows for rearward access to recess  36  for installation of components. Transverse translation of blocking piece  34  is constrained by a transverse projection  44 , made integral with blocking piece  34 , which substantially spans the transverse width of recess  36 . FIG. 18 further shows the positioning of blocking piece  34  within recess  36 .  
         [0038]    In FIG. 3 trigger  20  has been translated rearward into the firing position. Trigger bar  22  and firing element  28  have translated with trigger  20 . Triggerbar  22  has also been cammed downward through known means to disengage sear  26  from sear catch  30 . Firing element  28  is about to be propelled fully forward. Blocking piece  34  has moved downward to provide a clear forward travel path for firing element  28 . Vertical projection  35  no longer impedes the path of sear catch  30 . In FIG. 4 firing element  28  is shown after having moved fully forward. Releasing trigger  20  at this point will allow trigger  20  and triggerbar  22  to automatically reset to the battery position.  
         [0039]    [0039]FIGS. 5 and 6 show a link  50  which translates with trigger  20 . Link  50  engages a cam track  52  integral with blocking piece  34  and thereby controls the vertical motion of blocking piece  34 .  
         [0040]    [0040]FIG. 8 gives an overall view of blocking piece  34  while FIG. 9 shows cam track  52  more clearly. Cam track  52  has a horizontal segment  54  and an inclined segment  56 . The shape of cam track  52  is such that blocking piece  34  does not begin downward movement until horizontal segment  54  has been cleared.  
         [0041]    [0041]FIG. 7 shows link  50  more clearly. Link  50  has a camming stud  58  which rides in cam track  52  of blocking piece  34 . A connecting arm  60  is designed to connect trigger  20  with triggerbar  22  and provide a pivot for triggerbar  22 . Connecting arm  60  passes through a trigger hole  62  shown in FIG. 10 and on into a triggerbar hole  64  shown in FIG. 11. These relationships are shown more consisely in FIG. 13.  
         [0042]    Returning to FIG. 11, triggerbar  22  has a bearing surface  68  and a spring seat  66  to accomodate trigger return spring  24 . FIG. 12 shows how trigger return spring  24  engages spring seat  66 .  
         [0043]    [0043]FIG. 14 shows an assembly  70  of trigger  20 , triggerbar  22 , trigger return spring  24 , blocking piece  34 , and link  50  in the battery position. Connecting arm  60  serves to join trigger  20  to triggerbar  22 . Because of this feature, normal operation of the firearm will be precluded if link  50  is removed from assembly  70  since trigger  20  will thereby be disconnected from triggerbar  22 . Bearing surface  68  bears against blocking piece  34  in order to maintain proper alignment of triggerbar  22 . A left hand wind tends to force trigger return spring  24  out of spring seat  66 . Blocking piece  34  counters this tendency and serves to keep trigger return spring  24  properly positioned in spring seat  66 . Thus, if blocking piece  34  is removed from assembly  70 , triggerbar  22  will suffer misalignment and become disconnected from trigger return spring  24 , thereby precluding normal operation of the firearm. FIG. 15 shows assembly  70  with trigger  20  in the rearwardmost position. Bearing surface  68  rides along blocking piece  34  while trigger return spring  24  is maintained within spring seat  66 .  
         [0044]    [0044]FIG. 16 shows a slot  72  which accepts link  50 . Near the forward portion of slot  72  is an opening  76  of small width. Connecting arm  60  accesses trigger hole  62  and triggerbar hole  64  through opening  76 . The rearward portion of slot  72  is cut through as a full width window  74  into recess  36 . Camming stud  58  accesses cam track  52  through window  74 . The location of window  74  is positioned such that link  50  cannot be fully installed unless camming stud  58  properly engages cam track  52 , assuming that blocking piece  34  is present. This feature is shown in FIG. 17. Mandrel  46  limits the downward position of blocking piece  34  such that window  74  is sufficiently obstructed by blocking piece  34  to prevent the inadvertant installation of link  50  with camming stud  58  located above blocking piece  34 . Provided blocking piece  34  is present, link  50  can only be fully installed when camming stud  58  properly engages cam track  52 .  
         [0045]    Conclusion, Ramifications, and Scope  
         [0046]    Thus, the reader will see that the passive safety mechanism of this invention precludes normal operation of the firearm when safety components are absent, shows external evidence that safety components are absent, is resistant to improper assembly, consists of a minimum of parts, does not require a dedicated spring, and does not require a dedicated surface on the firing element.  
         [0047]    Although the description above contains many specificities, these should not be construed as limiting the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Many other variations are possible. For example, the connecting arm could be replaced by a separate pin; trigger, triggerbar, and link could be connected through alternate means; camming means other than a track and stud could be used; the spring seat can be changed in shape and location so as not to be dependent on the locking block, a trigger return spring other than the torsion type could be used, etc.  
         [0048]    Accordingly, the scope of the invention should be determined not by the embodiment(s) illustrated, but, by the appended claims and their legal equivalents.