Abstract:
The present invention comprises a new and improved one-piece trigger for a lever action rifle which eliminates trigger flop found on two piece factory triggers. The trigger allows the sear to slip up and past the half and full cock notches on the hammer via an elliptically shaped rigger pivot hole.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   Priority is claimed from provisional application U.S. Ser. No. 60/396,675 filed on Jul. 18, 2002, and incorporated by reference herein. 

   FIELD OF THE INVENTION 
   In general, the present invention relates to firearms. More particularly, the present invention relates to an improved one-piece trigger for a lever action rifle having an exposed hammer. 
   DESCRIPTON OF THE PRIOR ART 
   All rifles are equipped with a standard trigger that is designed by the manufacturer and installed at the factory. The “factory trigger” is entirely adequate for the average shooter, however, many shooters especially hunters and target shooters demand a better trigger action than is offered by the standard factory trigger. The perceived shortcomings of factory triggers usually consist of non-uniform trigger pull (creep and backlash), overtravel, heavy trigger pull and in the specific case of the MARLIN 336™ rifles the shortcoming is trigger flop. Trigger flop is caused by the design of the trigger installed on these rifles. 
   The MARLIN 336™ rifle is a lever action rifle. Manipulating a lever located on the underside of the rifle operates the action. When the lever is opened downward the bolt is opened cocking an exposed hammer which pivots rotatibly around a hammer screw. The hammer has two operating positions created by notches, which the sear of the trigger slips into, as the hammer is cocked. The first position is the half cock position. When the hammer is in the half cock position the rifle is considered safe. The shape of the half-cock notch locks the sear against the hammer and prevents the trigger from being pulled to fire the weapon. The second position of the hammer is the full cocked position. When the hammer is fully cocked, pulling the trigger will release the hammer and fire the weapon. A second safety feature on the MARLIN 336™ rifle is a trigger safety block. The trigger safety block stops the trigger from being pulled prior to the lever being fully closed and the bolt completely locked up inside the receiver. The trigger cannot be pulled to allow the sear to release the hammer and fire the weapon unless the lever is fully closed deactivating the trigger safety block. 
   In order to allow the weapon to be cocked without the operator having to pull the trigger to clear the notches as the hammer is cocked, the factory Marlin™ trigger is built of two separate pieces as shown in prior art  FIGS. 6 &amp; 7  of the present invention. The first piece is called the trigger shoe  94 . The second piece is called the sear  92 . The trigger shoe extends downwardly below the receiver and is the part of the trigger that is seen and pulled by the shooter to fire the weapon. The sear is hidden inside the receiver of the rifle and is the part which makes contact with the notches on the hammer holding it in its cocked position until the shooter releases it by pulling the trigger to fire the weapon. The two-pieces are pivotally attached two each other and pivot together over the trigger pin. The two-piece design allows the sear to move forward independently of the trigger to slip over the cock and half-cock notch on the hammer as it is cocked, even though the sear can slip over the notches it cannot move forward to release the hammer until the trigger is physically pulled. The trigger cannot be pulled until the lever is fully closed and the trigger safety block is depressed. While the two piece design functions reliably it allows the trigger to flop forward when the rifle is cocked prior to shooting. 
   Many target shooters and hunters find the floppy trigger distracting and detrimental to good marksmanship. The two piece design of the factory Marlin 336™ trigger is inherently more prone to failure than a one-piece design. This is due to the potential of dirt and powder residue build up and impede the function of the trigger. The two piece design is also more prone to mechanical failure because of the greater number of small parts that could fail. Additionally, the manufacture of a two piece trigger requires additional steps to machine the parts and assemble them into a finished rifle, making the rifle more expensive and less profitable to manufacture. Efforts of others to eliminate the trigger flop of the Marlin 336™ rifle have centered on improving or changing the design of the factory trigger. 
   One such effort is that of WILDWEST GUNS™ of Anchorage, Ak. Their product the HAPPY TRIGGER™ shown in prior art  FIG. 12  of the present invention eliminates the trigger flop of the Marlin™ trigger, however, it still incorporates multiple pieces in its design and manufacture. While an improvement over the factory trigger, the WILD WEST GUNS™ trigger is still composed of two or more pieces, and thus, is not as inherently reliable or as efficient to manufacture as a one-piece design would be. 
   Thus, there is a need for an improved one-piece trigger for a lever action rifle such as but not limited to the Marlin 336™ rifle that eliminates the floppy trigger, is more reliable in operation and is less expensive to manufacture and assemble. 
   SUMMARY OF THE INVENTION 
   In view of the above described disadvantages inherent in the triggers for the Marlin 336™ lever action rifle of the prior art, the present invention not only prevents the flop present in the standard factory trigger, but is also inherently more durable and less expensive to manufacture and assemble due to its one-piece design. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved one-piece trigger for a lever action rifle, such as the Marlin 336™ which has all of the advantages of the prior art and none of the disadvantages. 
   To attain this purpose the present invention essentially comprises a trigger shoe and sear machined from a single piece of steel or other metal of suitable hardness and durability. The design innovation that allows the sear to slip over the notches as the hammer is cocked and yet not be able to be pulled until the trigger block is depressed, is a change in the dimension and shape of the trigger pin hole. This change allows for variable geometry of the relationship between the trigger and the hammer during the operating cycle of the trigger. Variable geometry of the trigger is achieved by altering the trigger pin pivot hole from a round hole sized to fit the round trigger pin tightly, to an elliptical or oval shaped pivot hole. The elliptically shaped trigger pin pivot hole allows the trigger and sear to slip up and out slightly as the hammer is cocked giving enough clearance for the sear to slip over the half-cock and full-cock notches on the hammer. When the hammer is fully cocked spring tension from a mainspring forces the trigger back down into its original position where the sear cannot move forward until after the lever is fully closed releasing the trigger block and the trigger is pulled by the shooter. 
   There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
   In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in this application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
   Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way. 
   Therefore, an object of the present invention to provide a new and improved trigger for a lever action rifle such as but not limited to the MARLIN 336™ which eliminates the trigger flop found on the factory trigger. 
   It is a further object of the present invention to provide a trigger for a lever action rifle such as but not limited to the MARLIN 336™ that is less costly and more efficient to manufacture. 
   An even further object of the present invention is to provide a new and improved trigger for a lever action rifle such as but not limited to the MARLIN 336™ which is less costly to assemble into the finished rifle. 
   Still another object of the present invention is to provide a new and improved trigger for a lever action rifle such as but not limited to the MARLIN 336™ which provides a lighter and crisper trigger feel to the shooter than the factory trigger. 
   Another object of the present invention is to provide a new and improved trigger for a lever action rifle such as but not limited to the MARLIN 336™, which is stronger and more durable than the factory trigger. 
   Yet another object of the present invention is to provide a new and improved trigger for a lever action rifle such as but not limited to the MARLIN 336™ which is more reliable than the factory trigger. 
   An even further object of the present invention is to provide a new and improved trigger a lever action rifle such as but not limited to the MARLIN 336™ I with simplified operation and fewer parts than the prior art. 
   A still further object of the present invention is to provide a new and improved one piece trigger for a lever action rifle which may be installed and adjusted without the need of hiring a gunsmith. 
   These, together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages, and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated preferred embodiments of the invention. 

   
     BRIEF DESCRIPTION OF THE PICTORIAL ILLUSTRATIONS AND DRAWINGS 
       FIG. 1  is pen and ink drawing of a preferred embodiment of the invention installed in the trigger floor plate of the rifle and showing the relationship between the trigger and the hammer. 
       FIG. 2  is a pictorial illustration of the trigger floor plate which the trigger and hammer are installed in showing the hammer block mechanism. 
       FIG. 3  is a schematic diagram and parts list for a MARLIN 336™ lever action rifle showing the relationship of parts discussed in the present application to each other. 
       FIG. 4  is a pen and ink drawing of the invention showing the relationship of the hammer and trigger as the hammer is being cocked. 
       FIG. 5  is a pen and ink drawing of the invention showing the relationship of the hammer and trigger when the hammer is completely cocked. 
       FIG. 6  is a pen and ink drawing showing the prior art (factory trigger) as the parts are assembled. 
       FIG. 7  is a pen and ink drawing showing the individual parts of the prior art (factory trigger). 
       FIG. 8  is a pen and ink drawing showing the preferred embodiment of the invention by itself. 
       FIG. 9  is a pen and ink drawing showing an alternative embodiment of the invention. 
       FIG. 10  is a pen and ink drawing showing another alternative embodiment of the invention. 
       FIG. 11  is a pen and ink drawing showing yet another alternative embodiment of the invention. 
       FIG. 12  is a pictorial illustration of the prior art WILDWEST GUNS™ HAPPY TRIGGER™ 
       FIG. 13  is an exploded view of a further embodiment of the present invention incorporating a set screw for the adjustment of the trigger safety block. 
       FIG. 14  is a further illustration of the present invention incorporating a set screw for the adjustment of the trigger safety block. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to  FIG. 1  and  FIG. 2  is a trigger group  10  of a lever action rifle depicted in  FIG. 3 . The trigger group  10  is comprised of a trigger guard plate  20 , a hammer  40 , a one-piece trigger  60  and a trigger safety block  80 . The trigger guard plate  20  forms part of the rifle receiver as shown in  FIG. 3 . Mounted in the trigger guard plate  20  are the hammer  40 , and the one-piece trigger  60  and the trigger safety block  80 . 
   Still referring to  FIG. 1 , the hammer  40  pivots on a hammer screw  42  and has a spur  44  to which thumb pressure is applied to cock the hammer  40  and a convex surface  46  which pivots against a concave surface  70  of a sear  62  of the one-piece trigger  60 . Located on the convex surface  46  is a half-cock notch  48  and a full-cock notch  50  ( FIG. 4 ). The one-piece trigger  60  is mounted in the trigger guard plate  20  as shown in  FIG. 1 . 
   Shown in  FIGS. 4 and 5 , the one-piece trigger  60  consists of the sear  62 , a trigger shoe  64 , a rear surface  65  and a trigger pivot hole  66 . The rear surface  65  is dimensioned to interact with the trigger safety block  80  to prevent the trigger  60  from being pulled prior to the lever (not shown) being fully closed. The trigger pivot hole  66  is shaped generally in an oblong or oval shape. The trigger pivot hole  66  has a first end  67 , a second end  69 , a bottom side  71 , and a topside  73 . The first end  67  and the second end  69  are sized so that a round trigger pin  68  fits tightly when it is positioned at either first end  67  or second end  69 . The bottom side  71  and the topside  73  are elongated to create the oval or oblong shape of the trigger pivot hole  66 . Additionally the bottom side  71  and the topside  73  are curved slightly so that the curvature of the bottom side  71  and the topside  73  matches the curvature of the concave surface  70  of the sear  62 . The sear  62  also has a point  72 . The one-piece trigger  60  pivots on the round trigger pin  68  that passes through the trigger pivot hole  66  and is secured to the trigger guard plate  20  as shown in  FIG. 1 . 
   The hammer  40  and the one-piece trigger  60  of  FIG. 1  work together to control the firing of the rifle shown in  FIG. 3 . As the hammer is cocked (shown in  FIGS. 1 ,  4  &amp;  5 ) the convex surface  46  of the hammer  40  rotates against the concave surface  70  of the sear  62 . The one-piece trigger  60  shifts from its starting position biased against the first end  67  of the trigger pivot hole  66  upwards until it is biased against the second end  69  of the trigger pivot hole  66 . The upward motion changes the geometry of the relationship between the sear  62  and the hammer  40  allowing the point  72  of the sear  62  to clear the half-cock notch  48  and the full-cock notch  50  as the hammer  40  is cocked. The point  72  of the sear  62  first slips into the half-cock notch  48  of the hammer  40 . At this time, the rifle is considered in a safe condition because the point  72  of the sear  62  is locked into the half-cock notch  48  and the one-piece trigger  60  cannot be pulled to release the hammer  40 , which is biased rearward under spring pressure (not shown), to strike the firing pin (not shown). If the cocking motion is continued, the hammer  40  continues to pivot around the hammer screw  42  and the point  72  of the sear  62  next slips into the full-cock notch  50 . When the hammer  40  is cocked to either the half-cock position or the full-cock position pressure from a compressed mainspring  54  puts pressure on the one-piece trigger  60  again biasing it against the first end  67  of the trigger pivot hole  66 . When the one-piece trigger  60  is in this position it cannot clear the half-cock notch  48  or the full-cock  50  and thus, it is unable to release the hammer  40  to strike the firing pin (not shown) until the trigger safety block  80  is deactivated by the closing of the lever (not shown). When the lever (not shown) is closed deactivating the trigger safety block  80  the rifle (not shown) is then ready to fire when the shooter pulls the one-piece trigger  60  by putting finger pressure on the trigger shoe  64  to cause the one-piece trigger  60  to pivot on the trigger pin  68  and release the point  72  of the sear  62  from the full-cock notch  50  of the hammer  40 . When the sear  62  is released the hammer  40  is propelled under pressure of the main spring  54  pushing forward on a hammer rod  52  to pivot forward on the hammer screw  42  and strike the firing pin (not shown) discharging the weapon. The trigger safety block  80  shown in  FIGS. 1 ,  2  &amp;  3  consists of a spring loaded bar hingeably attached to the trigger guard plate  20 . When the trigger safety block  80  is in the down position the end of said trigger safety block  80  contacts the rear surface  65  of the trigger  60  preventing said trigger  60  from being pulled. When the lever (not shown) is fully closed, it pushes the trigger safety block  80  into its up position causing the trigger safety block  80  to cease to contact the rear surface  65  of the trigger  60  and allowing the trigger  60  to be pulled causing the rifle to fire. 
   An alternative embodiment of the present invention shown in  FIG. 9  is a one-piece trigger  100  manufactured having a trigger pivot hole  101  that is cut oversize. Molded inside the trigger pivot hole  101  is a polymer or elastomeric bushing  102  with a metal insert  103  through which a trigger pin  104  is inserted. As the hammer (not shown) is cocked the polymer or elastomeric bushing  102  will flex allowing a point  106  of a sear  107  to clear the half cock notch (not shown) and the full cock notch (not shown) of the hammer (not shown). The plastic or elastomeric bushing  102  would then flex back into its original position under spring pressure from the hammer spring (not shown) and function essentially the same as the one-piece trigger  60  with the oblong pivot hole  66  ( FIG. 1 ) that is described above. 
   Another alternative embodiment of the present invention shown in  FIG. 10  is a one-piece trigger  110  is manufactured having a trigger pivot hole  112  that is round in shape and cut oversize. Inside the trigger pivot hole  112  is a movable metal bushing  114  with an offset pivot hole  116 . In operation the movable metal bushing  114  would rotate to allow a point  118  of a sear  119  to clear the half cock notch (not shown) and the full cock notch (not shown) as the hammer (not shown) is cocked. 
   Yet another alternative embodiment of the present invention shown in  FIG. 11  is a one-piece trigger  130  manufactured having a trigger pivot hole  132  that is round in shape and cut oversize. Inserted in the trigger pivot hole  132  is a tightly fitted metal bushing  134  with an oval or elliptically shaped hole  136 . The oval or elliptically shaped hole  136  would be dimensioned identically and function identically to the trigger pivot hole  66  of the one-piece trigger  60  as shown in  FIG. 8 . 
   Still another alternative embodiment of the present invention shown in  FIGS. 13 and 14  is a one piece trigger  150  manufactured having a set screw  152  inserted in a threaded hole  154  wherein the set screw  152  can be screwed in or out to tune the interaction of the rear surface  156  of the trigger  150  with the trigger safety block  80  so that the trigger may be easily fitted to the trigger safety block  80  without having to machine and polish the rear surface  65  or the trigger safety block  80 . 
   Yet another alternative embodiment of the present invention (not shown) would include an over travel adjustment screw for the adjustment or elimination of trigger over travel. 
   Changes may be made in the combination, operations, and arrangements of various parts and elements described herein without departing from the spirit and scope of the invention. 
   PARTS LIST 
   
       
         10  Trigger Group 
         20  Trigger Plate 
         40  Hammer 
         60  One Piece Trigger 
         40  Hammer 
         42  Hammer Screw 
         44  Hammer Spur 
         46  Convex Surface 
         48  Half-cock Notch 
         50  Full Cock Notch 
         52  Hammer Rod 
         54  Mainspring 
         60  Trigger 
         62  Sear 
         64  Trigger Shoe 
         65  Rear Surface 
         66  Trigger Pivot Hole 
         67  First End 
         68  Trigger Pin 
         69  Second End 
         70  Concave Surface 
         71  Bottom Surface 
         72  Point 
         73  Top Surface 
         80  Trigger Safety Block 
         90  Prior Art Trigger Mechanism 
         94  Prior Art Trigger 
         96  Prior Art Trigger Hole 
         99  Pivot Art Sear 
         100  Trigger w/t Polymer Bushing 
         102  Polymer Bushing 
         103  Metal Insert 
         104  Trigger Pin 
         106  Point 
         107  Sear 
         110  Trigger w/t Movable Bushing and Offset Hole 
         112  Trigger Pivot Hole 
         114  Metal Bushing 
         116  Offset Pivot Hole 
         118  Point 
         119  Sear 
         130  Trigger w/t Oblong Hole in Bushing 
         132  Trigger Pivot Hole 
         134  Metal Bushing 
         136  Oval Hole 
         150  Trigger with Set Screw Adjustment 
         152  Set Screw 
         154  Threaded Hole 
         156  Rear Surface