Abstract:
A reset apparatus for use in a firearm, comprising: a compression spring; a biasing member has a first end and a distal end wherein the compression spring is attached proximate to the first end of the biasing member; a notch disposed on the biasing member for cooperation with a trigger bar, wherein the trigger bar comprises a longitudinal axis defined by a front portion and a rear portion, wherein the front portion is mechanically cooperated with a firearm trigger; and wherein the compression spring communicates a force through the biasing member and onto the trigger bar in a direction substantially perpendicular to the longitudinal axis of the trigger bar.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/953,610, filed Jul. 29, 2013, which is a continuation of U.S. patent application Ser. No. 12/912,715, filed Oct. 26, 2010, now U.S. Pat. No. 8,510,980, both of which are incorporated in their entirety herein by reference. 
    
    
     FIELD OF INVENTION 
     This invention relates to an apparatus for enhancing the lateral movement of a trigger bar in a semi-automatic firearm when a trigger reset event occurs. In particular, this invention relates to enhancing the mechanical impact between a trigger bar and a sear as a firearm trigger is released. 
     BACKGROUND OF THE INVENTION 
     A striker-type fire control mechanism is commonly used in modern semi-automatic pistols. In striker fired pistols, the trigger is connected to a trigger bar. Movement of the trigger causes movement of the trigger bar, which in turn causes a sear to rotate about a pivot point. Upon rotation of the sear, a spring is compressed and an upper portion of the sear is displaced relative to the firing pin. Upon displacing the sear a sufficient distance to clear a depending leg of the firing pin, the firing pin is urged forward by a spring and strikes the rear of the cartridge, thereby discharging the firearm. After the firearm discharges, the trigger must be released forward to a point where the trigger bar re-engages the sear, resetting the trigger for the next shot. 
     In some firearms, the trigger reset is aided by a single tensioning coil spring located forward of the magazine channel. This trigger return spring performs the dual role of returning the trigger to a forward position and pulling the rear end of the trigger-bar back under the sear. During the forward return of the trigger bar, but before re-engagement with the sear, the trigger bar is laterally displaced out of cooperation with the sear such that the firearm may not yet be fired. As the trigger bar continues to move forward, the rear end of the trigger bar is pulled back under the sear, re-engaging the sear so that the firearm is again ready to fire. 
     The mechanical impact that occurs between the trigger bar and sear upon re-engagement physically communicates to the operator, through the operator&#39;s finger on the trigger, that the trigger reset is complete and that the firearm may be fired, i.e., that the firearm is set to fire when the trigger is pulled back again. However, because this mechanical impact can be slight, the physical communication to the operator through the trigger is subtle, and thus it can be difficult for a firearm operator to ascertain when trigger reset has occurred. 
     BRIEF SUMMARY OF THE INVENTION 
     Several embodiments of the present invention answer the above and other needs by providing a reset assist mechanism for biasing the trigger bar as the reset event occurs. 
     In one embodiment, the invention may be characterized as a reset apparatus for use in a firearm, comprising: a compression spring; a biasing member comprising a first end and a distal end wherein the compression spring is attached proximate to the first end of the biasing member; a notch disposed on the biasing member for cooperation with a trigger bar, wherein the trigger bar comprises a longitudinal axis defined by a front portion and a rear portion, wherein the front portion is mechanically cooperated with a firearm trigger; and wherein the compression spring communicates a force through the biasing member and onto the trigger bar in a direction substantially perpendicular to the longitudinal axis of the trigger bar. 
     In another embodiment, the invention may be characterized as method for signaling a trigger reset event comprising: attaching a compression spring to a biasing member, the biasing member comprising a first end and a distal end wherein the compression spring is attached proximate to the first end of the biasing member; disposing the biasing member to be in mechanical cooperation with a trigger bar, wherein the trigger bar comprises a front portion and a rear portion, the front portion being mechanically cooperated with a firearm trigger; applying a force from the biasing member onto the trigger bar in a direction substantially perpendicular to an axis of the trigger bar (longitudinal axis of the trigger bar, or longitudinal firing axis), the axis defined by the front and rear portions of the trigger bar. 
     In yet another embodiment, the invention may be characterized as a means for magnifying an impact resonance between a sear body and a trigger method for use with a modular irrigation controller comprising: a compression spring; a biasing member, the biasing member comprising a first end and a distal end wherein the compression spring is attached proximate to the first end of the biasing member; a notch disposed on the biasing member for cooperation with a trigger bar, wherein the trigger bar comprises a longitudinal axis defined by a front portion and a rear portion, wherein the front portion is mechanically cooperated with a firearm trigger; and wherein the compression spring communicates a force through the biasing member and onto the trigger bar in a direction substantially perpendicular to the longitudinal axis of the trigger bar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects, features and advantages of several embodiments of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings: 
         FIG. 1  is a simplified schematic perspective view of a fire control mechanism according to an embodiment of the present invention; 
         FIG. 2  is a simplified schematic perspective view of the sear of  FIG. 1 ; 
         FIG. 3  is a simplified schematic perspective view of the engagement of the sear and a trigger bar of the fire control mechanism; 
         FIG. 4  is a simplified schematic view of the fire control mechanism of  FIG. 1 ; 
         FIG. 5  is a simplified schematic view of the fire control mechanism in which the trigger bar is displaced away from the sear; 
         FIG. 6  is an enlarged perspective view of a biasing member of one embodiment of the present invention; 
         FIG. 7  is a side view of the biasing member of one embodiment of the present invention in which the biasing member is cooperated with a compression spring; 
         FIG. 8  is a left side view of the a sear housing block including a sear channel and an interior flange; 
         FIG. 9  is a right side view of the sear housing block including a channel and trigger bar (in this perspective view, a distal end of the biasing member is also shown); 
         FIG. 10  is a cut-away top view of the sear housing block in which the biasing member and the compression spring are mechanically cooperated with the trigger bar (the trigger bar is laterally displaced in the direction indicated by arrow D out of cooperation with cam portion  68 ; in this configuration, the compression spring  650  is compressed between the plunger head of biasing member and the sear flange such that a force is exerted on the trigger bar in the direction indicated by arrow F); and 
         FIG. 11  is a cut-away top perspective view of the sear housing block in which the biasing member and the compression spring are mechanically cooperated with the trigger bar (in this configuration, the trigger bar has been returned to its laterally unbiased position and is in cooperation with sear disposed under the cam portion). 
     
    
    
     DETAILED DESCRIPTION 
     The following description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of exemplary embodiments. The scope of the invention should be determined with reference to the claims. 
     Referring now to  FIG. 1 , the fire control mechanism  18  includes a striker-type firing pin  19  having a forward firing pin portion  20  and a depending leg  22  extending down from the firing pin portion  20 . The fire control mechanism  18  also includes a sear assembly  26  that is engagable by the firing pin  19 . The sear assembly  26  is operably engagable with a trigger assembly that includes the trigger  28 . Upon operation of the handgun (via movement of the trigger  28 ), a surface of the depending leg  22  selectively engages the sear assembly  26 . The trigger  28  is pivotally connected to a trigger bar  30  via a pin  35 . The trigger bar  30  may be biased in lateral directions via a spring or the like. Rearward movement of the trigger  28  causes movement of the trigger bar  30  in a rearward longitudinal direction. When the trigger  28  is actuated by being pressed in a rearward direction, the trigger  28  pivots about a pin  38 , thereby transmitting rearward longitudinal movement to the trigger bar  30  via the pin  35 . Longitudinal movement of the trigger bar  30  in a rearward direction, in turn, actuates the sear assembly  26 , e.g., it unblocks the sear assembly, thereby allowing the firing pin  19  to translate in a forward direction under the action of a decompressing firing pin spring for the firing pin portion  20  to engage a cartridge and fire the handgun. 
     The fire control mechanism  18  is further described in U.S. Pat. No. 7,617,628 (Curry), the entirety of which is incorporated herein reference. 
     Referring now to  FIG. 2 , in some embodiments the sear  50  is an elongated member having a major axis M. The elongated member is pivotal about the fulcrum  58 , which extends through the member in a direction that is substantially perpendicular to the direction in which the major axis M extends. The forward portion  59  of the sear  50  is configured to have both a ramp portion  67  and a cam portion  68 . From a side elevation, the cam portion  68  may have a cross-sectional configuration having an upper rounded surface  71  and a lower rounded surface  73 , both of which extend perpendicular to the direction in which the major axis M extends and parallel to the direction in which the pivot axis defined by the fulcrum  58  extends. The ramp portion  67  extends downward from the lower rounded surface  73 . A downward-facing surface of the ramp portion  67  is substantially flat. Both the forward portion  59  and the rearward portion are dimensioned and configured to have substantially the same masses relative to the fulcrum  58 . Thus, the sear  50  is substantially balanced front-to-back. 
     Referring now to  FIG. 3 , the dimensions and configuration of the sear  50  are such that the lower rounded surface  73  on the cam portion  68  acts cooperatively with the trigger bar  30 . In particular, the lower rounded surface  73  engages a corresponding sloped surface  75  on the trigger bar  30  such that as the trigger is pulled, the trigger bar  30  moves rearward in the direction of an arrow A and in a plane that is at least partially coplanar with a plane in which the sear  50  rotates. In doing so, the sloped surface  75  on the trigger bar  30  engages the lower rounded surface  73  of the cam portion  68 , the sear  50  is rotated in the direction of an arrow B, and the forward end of the sear  50  is urged upward, thereby causing the rearward surface  60  to move downward about the fulcrum  58 . At a pre-selected distance, the sear  50  is pivoted fully downward against the sear spring to allow the leg  22  of the firing pin  19  to disengage from the rearward surface  60 . 
     Referring now to  FIG. 4 , the depending leg  22  of the firing pin  19  is engaged by the sear  50 . As the trigger is pulled in the rearward direction, the trigger bar  30  likewise moves rearward, and the sloped surface  75  on the trigger bar  30  engages the lower rounded surface  73  of the sear  50  to urge the front of the sear  50  up and the rearward surface down (the sear  50  is pivoted about the fulcrum  58 ). The firing pin  19  is released and travels forward. The trigger bar  30  is fully extended in the rearward direction. 
     Referring now to  FIG. 5 , after the trigger has been released, the trigger bar  30  likewise moves forward and also laterally out of registration with the sear  50 . Once the trigger bar  30  has moved sufficiently in the forward direction, the sloped surface  75  reengages the lower rounded surface  73  on the cam portion  68  of the sear  50 . The trigger bar  30  may be provided with a track or guide  89  in the sear housing block  52 , for the purpose of laterally guiding the trigger bar  30  during lateral displacement. As should be appreciated, the connection of the trigger  28 , trigger bar  30 , and the sear assembly  26  is such that the trigger bar  30  can be laterally displaced when pressure is exerted on the trigger bar  30  in a direction that is perpendicular to the direction in which the longitudinal firing axis extends. 
       FIG. 6 , is perspective view of a biasing member  600 . Shown is a cylindrical rod  610 , a cylindrical plunger head  620 , a first end  630 , a distal end  640 , a compression spring  650  and a notch  660 . 
     The biasing member  600  is comprised of the cylindrical rod  610  with the cylindrical plunger head  610  of a greater diameter and disposed on one side of the cylindrical rod  610 . The top surface of the cylindrical plunger head  620  includes a surface forming the first end  630  of the biasing member  600 . At the opposite end of the rod  610  is the distal end  640 . The notch  660  is disposed in one surface of the cylindrical rod  610  nearer to the distal end  640  than the first end  630  of cylindrical plunger head  620 . The notch  660  is of a size and shape suited to accommodate the trigger bar  30 , such that the trigger bar  30  is at least partially laterally constrained, i.e., is not free to slide side-to-side independently of the biasing member  600 , within the notch  660  when the biasing member  600  is cooperated with the trigger bar  30 . The trigger bar  30  is not constrained longitudinally, i.e., is free to slide forward and backward independently of the biasing member  600 , within the notch  660  when the biasing member  600  is cooperated with the trigger bar  30 . 
     In operation, the biasing member  600  is cooperated with the trigger bar  30  via the notch  660 . That is, the trigger bar  30  sits within notch  660  such that the longitudinal axis of trigger bar  30  is substantially perpendicular to the longitudinal axis of the biasing member  600  and parallel to the firing axis (longitudinal firing axis). In this configuration, the trigger bar  30  is allowed to move in its forward and rearward longitudinal directions as it is not fixed to any point within the notch  660  on the biasing member  600 . The lateral axis of the trigger bar is substantially parallel to the longitudinal axis of the biasing member  600  and perpendicular to the longitudinal firing axis. In this configuration, the trigger bar  30  moves in its side-to-side lateral directions and is constrained within the notch  660  on the biasing member  600 . 
       FIG. 7  is a side orthogonal view of a biasing member  600  cooperated with a compression spring  650 . Shown is a rod  610  with a plunger head  620 , a first end  630 , a notch  660 , a distal end  640  and a compression spring  650 . 
     Fixed under the plunger head  620 , is the compression spring  650  such that the rod  610  is disposed within the inner circumference of the compression spring  650 . In this configuration, the compression spring  650  can be compressed against the plunger head  620  in response to lateral displacement of the trigger bar  30  such that movement of the rod  610  and the plunger head  620  causes compression of the compression spring  650 . 
     In operation, the notch  660  is cooperated with the trigger bar  30  such that the trigger bar  30  freely moves in the forward and backward longitudinal directions. However, the notch  660  will affect the motion of the trigger bar  30  in the lateral direction perpendicular to the longitudinal axis (longitudinal firing axis) of the trigger bar  30 . When lateral displacement of the trigger bar  30  occurs, the compression spring  650  compresses against the plunger head  620  and around the rod  610 , translating a lateral force into the trigger bar  30  via the notch  660 . 
       FIG. 8  is a left perspective view of a sear housing block  52 . Show is a trigger bar  30 , a sear housing block  52 , a sear channel  810  and a flange  820 . 
     The sear channel  810  is a cylindrical hole in the sear housing block  52  in a direction perpendicular to the longitudinal axis (longitudinal firing axis) of the trigger bar  30 . The diameter of the sear channel  810  is narrowed by the flange  820  disposed within the sear channel  810  and beneath the surface of the sear housing block  52 . The dimensions of the sear channel  810  and the flange  820  are such that the distal end  640  of the biasing member  600  can fit into the inner diameter of the flange  820  within the sear channel  810 . However, the diameter of the compression spring  650  is larger than the inner diameter of the flange  820  and yet smaller than the inner diameter of the sear channel  810 . Thus, when the biasing member  600  is inserted into the sear channel  810 , the compression spring of the biasing member presses up against the flange  820  permitting the rod  610  to move in the lateral direction relative to the longitudinal axis of the trigger bar  30  as the compression spring  650  is compressed or decompressed. 
     In practice, the biasing member  600  together with the compression spring  650  is inserted into the sear channel  810 . Because of the relative dimensions of the compression spring  650  and the rod  610 , the larger diameter compression spring cooperates with the flange  820  allowing the rod  610  to penetrate sear housing block  52  via the inner diameter of the flange  820 . Inside the sear housing block  52 , the trigger bar  30  cooperates with the notch  660  on the rod  610  such that when the trigger bar  30  moves in a lateral direction, a lateral force is imparted on the rod  610  via the notch  660  causing the compression or decompression of the compression spring  650 . Compression of the compression spring  650  occurs when the trigger bar  30  is moved laterally in a direction away from the left side of the sear housing block  52 . Upon compression of the compression spring  650 , the biasing member  600  exerts a force of opposite direction on trigger bar  30 . This force exerted by the biasing member  600  tends to restore the trigger bar  30  back into cooperation with the sear  50 . 
       FIG. 9 , is a right perspective view of a sear housing block  52 . Shown is a trigger bar  30 , a guide  89  and a distal end  640  of a biasing member  600 . 
     The biasing member  600 , is shown inserted into the sear channel  810  and mechanically cooperated with the trigger bar  30  such that the distal end  640  is visible from the right perspective view of the sear housing block  52 . The geometry of the guide  89  is such that the trigger bar  30  is moveable along its lateral axis. 
     In practice, when the trigger bar  30  is laterally displaced, the biasing member  600  exerts a restoring force on the trigger bar  30 , in a direction into the page, forcing the trigger bar  30  back into mechanical cooperation with the sear  50 . 
       FIG. 10  depicts a top perspective cut away view of the sear housing block  52 , wherein the biasing member  600  is fully inserted into the sear channel  810  and mechanically cooperated with the trigger bar  30  and wherein the trigger bar  30  is displaced laterally out of cooperation with cam portion  68 . Shown is the distal end  640 , the rod  610 , the cam portion  68 , the compression spring  650 , the plunger head  620 , the first end  630 , the flange  820  and the frame  110 . 
     In this configuration, the cam portion  68 , the biasing member  600  and the trigger bar  30  are all disposed within the sear housing block  52 . The cam portion  68  is elevated above the trigger bar  30  which is in turn disposed above the biasing member  600 . Mechanically cooperated, the trigger bar  30  and the biasing member  600  are laterally displaced in the direction of arrow D such that plunger head  620  is pulled into sear channel  810 . Lateral displacement of the trigger bar  30  and the biasing member  600  results in compression of compression spring  650  against flange  820 . 
     In practice, after a shot has been fired, the trigger bar  30  is pulled in the forward longitudinal direction, indicated by arrow T, by a trigger return spring (not depicted) that is located forward of the magazine channel. During this forward return, the trigger bar  30  is laterally displaced out of cooperation with the cam portion  68  of the sear  50 . While the trigger bar  30  is laterally displaced out of cooperation with the sear  50 , the firearm may not yet be fired. Due to the mechanical cooperation between the trigger bar  30  and the biasing member  600 , the lateral displacement of trigger bar  30  results in a corresponding lateral displacement of the biasing member  600  with respect to the longitudinal axis (longitudinal firing axis) and in the direction of arrow D. The displacement of the biasing member  600  in turn causes the compression of the compression spring  650  between the plunger head  620  and the flange  820  such that the compression spring  650  exerts a force on the plunger head  30  in the direction indicated by arrow F. This force is translated along the rod  610  and into the trigger bar  30  so that the trigger bar  30  is also forced in the lateral direction of arrow F. This restoring force will tend to return the trigger bar  30  under the cam portion  68  such that the trigger bar  30  is re-cooperated with the sear  50 . Upon reengagement with the sear  50  by the trigger bar  30 , the trigger reset event will be complete, allowing the fire to be fired. 
     Absent the biasing member  600  of the present embodiment, a stock firearm relies on the forward force provided by a trigger return spring in the direction of arrow T in order to both laterally restore the trigger bar  30  into cooperation with the sear  50  and return the trigger to a forward position. Thus, in the event that the trigger return spring were to malfunction, trigger reset would be difficult because there is no method with which to re-position the trigger bar  30  beneath the cam portion  68  such that the trigger bar  30  and the sear  50  are mechanically cooperated. However, with the present embodiment, due to the lateral force imparted on the trigger bar  30  by the biasing member  600 , the trigger bar  30  maintains a relationship with the cam portion  68 . As such, trigger reset can be accomplished so long as the firearm operator is able to manually restore the trigger  28  to a forward position. 
       FIG. 11  depicts a top perspective cut away view of the sear housing block  52 , wherein biasing member  600  is inserted into the sear channel  810  and mechanically cooperated with the trigger bar  30  and wherein the trigger bar  30  is mechanically cooperated with the cam portion  68 . Shown is a distal end  640 , a rod  610 , a cam portion  68 , a compression spring  650 , a plunger head  620 , a first end  630 , a flange  820  and a frame  110 . 
     In this configuration, mechanically cooperated, the trigger bar  30  and the biasing member  600  are laterally restored such that the trigger bar  30  is re-cooperated with the sear  50 . As such, the compression spring  650  is disposed between the flange  820  and the plunger head  620  and is uncompressed. In this position, the first end  630  of the plunger head  620  is in contact with the interior frame surface  110 . 
     In practice, it is the impact resonance that occurs between the trigger bar  30  and the sear  50  upon re-engagement, that physically communicates to the operator, that the trigger reset (trigger reset event) is complete, i.e., that the firearm may be fired. However, in firearms lacking the benefits of the present embodiment, the mechanical impact between the trigger bar  30  and the sear  50  upon re-engagement can be so insignificant, that it is often difficult for an operator to ascertain when the re-cooperation has occurred, i.e., when the trigger reset has completed. More specifically, in most stock firearms, there is only one lateral force exerted on the trigger bar  30  that originates from the trigger return spring. However, the trigger return spring, located forward of the magazine channel, is too distant from the location of the trigger reset event to cause an appreciable mechanical impact as the trigger bar  30  rejoins the sear  50 . 
     The biasing member  600  of the present embodiment serves to enhance the mechanical impact between the trigger bar  30  and the sear  50  without adversely affecting the trigger pull weight. As the trigger bar  30  moves in the forward longitudinal direction of arrow T, the lateral displacement of the trigger bar  30  is corrected by both the lateral restoring force imparted by biasing member  600  and the lateral force due to the effects of the trigger return spring. That is, in some embodiments, the trigger bar  30  receives a lateral restoring force from two independent sources, the trigger return spring and the biasing member  600 . The addition of the lateral force contributed by biasing member  600  enhances the mechanical impact between the trigger bar  30  and the sear  50  as the trigger bar  30  and the sear  50  reconnect. This added force in turn enhances the impact resonance at the trigger reset event, allowing an operator to more easily ascertain when the reset even has occurred. Furthermore, the longitudinal movements of the trigger bar  30  are not significantly impeded by the mechanical cooperation with the notch  660  of the biasing member  600 . Because the trigger bar  30  is allowed to slide freely in the forward and rearward longitudinal directions within the notch  660 , the mechanical cooperation of the trigger bar  30  and the biasing member  600  does not impact the trigger pull weight. 
     Additionally, a secondary impact resonance is created between the first end  630  of the biasing member  600  and the interior surface of the frame  110 . As the compression spring  650  decompresses and the trigger bar  30  is laterally biased back into cooperation with the sear  50 , the biasing member  600  is also laterally biased, in the direction opposite of arrow D, such that the plunger head  620  re-emerges from the sear channel  810  such that the first end  630  of the plunger head  620  contacts the interior of the frame  110 . This mechanical impact contributes a secondary impact resonance to the operator, facilitating an indication of when the trigger reset event has occurred.