Patent Application
20050183311
The present invention relates to a fire control or trigger mechanism for a firearm and more particularly to a trigger mechanism having a series of adjustable engagement settings.
A firearm trigger serves the purpose of initiating the firing sequence of the firearm. Typically, upon actuating the trigger, a sear operatively connected thereto is disengaged from locking engagement with a hammer/striker or the firing pin of the firearm, which in turn strikes a round of ammunition within the firing chamber. The sensitivity of the trigger thus is of particular importance in the operation of the firearm. For example, too heavy a trigger pull generally is undesirable since it can lead to jerking of the trigger that can cause shifting or misalignment of the weapon immediately prior to firing and spoil the shooter's aim. On the other hand, too light a trigger pull can raise issues of inadvertent or unintentional discharge of the firearm, especially if dropped or otherwise jarred. Further, with multi-barrel firearms, the trigger pull must not be too light to avoid doubling, that is, an undesirable or unintentional release of a second striker, which can cause the firing of more than one round at the same time.
The trigger and sear generally are calibrated so as to provide an engagement between these parts that should insure a desired trigger pull or response. However, because of normal manufacturing tolerances, this engagement can vary from sharp to loose. This variation or looseness is described as trigger “take-up”. In addition, after extended use, further looseness or take-up can develop in the engagement between the trigger bar and the sear. Such “take-up” or looseness in the action of the trigger is undesirable from a user's standpoint since the accuracy of the shot depends in large measure on the responsiveness of the trigger, and thus the sharper the trigger response, the more accurate the marksmanship.
Some shooters accordingly will try to sharpen or adjust the responsiveness of the trigger to their own preferences, though often to such an extent that the firearm becomes unsafe without their realizing that the newly adjusted trigger setting poses a danger. Since the area of engagement between the trigger and the sear is such a small amount, typically between about 0.024 inches to 0.027 inches, measuring a setting typically requires the use of an optical comparator, and therefore, it is difficult for the user to determine the resulting new settings upon adjustment and the dangers that may result from a setting that is too small. Thus, resetting the firearm to the original factory setting or determining if the setting is safe generally is not possible for the ordinary user.
Thus, what is needed is an apparatus that enable easy and concise adjustment of various operating parameters of a firearm trigger assembly to a desired user setting to “sharpen” the trigger up to a minimum safe level of operation.
Briefly described, in accordance with the present invention, there is provided a fire control assembly or trigger mechanism for firearms having a series of adjustments for adjusting various engagements or operative settings of the components of the trigger mechanism for adjusting or “sharpening” the responsiveness and function or operation of the trigger mechanism to suit user preferences, while maintaining proper operation of the trigger mechanism. The trigger mechanism of the present invention generally includes a moveable trigger mounted within a trigger housing and a sear adapted to engage the trigger for preventing movement of the firing pin or a hammer/striker of the firearm in which the present trigger mechanism is mounted. The trigger is biased toward a non-engaged, rest position in which it blocks movement of the sear out of engagement with the firing pin until the trigger is moved during a firing operation to fire a round of ammunition from the firearm.
The trigger mechanism of the present invention further includes a series of adjustment mechanisms for adjusting approximately five different operational features of the trigger mechanism. Among the adjustment mechanisms are an over-travel adjustment and a trigger pull adjustment. The over-travel adjustment helps set or fix the amount of rearward movement of the trigger after sear or hammer release, while the trigger pull adjustment adjusts the force required to move the trigger to a position to release the sear. The over-travel and trigger pull adjustment mechanisms typically include setscrews, pins, or other similar devices that are received within the bores formed within the trigger housing. The position of the setscrews or pins is adjustable by engagement of a tool, such as a screwdriver or similar tool, into a head portion thereof for moving the adjustment screws longitudinally along their respective bores.
In addition, a minimum and maximum trigger engagement adjustment is provided, which includes a first or outer sleeve or screw that projects through a forward portion of the trigger. Typically, the maximum trigger engagement adjustment is set or fixed at the factory to provide a maximum trigger engagement or safety limit for the trigger mechanism. A minimum trigger engagement screw or pin will further be received within the outer sleeve or first engagement screw and will be adjustably moveable therealong to set a minimum trigger engagement for the trigger mechanism. Lastly, a trigger block adjustment will be provided for adjusting the travel or engagement between a safety and a rear arm portion of the trigger. The trigger block adjustment typically will include a set screw or pin received in the rear arm of the trigger, with its position with respect to the safety generally being factory set and can be fixed against further adjustment.
Various objects, features and advantages of the present invention will become apparent to those skilled in the art upon a review of the following detailed description, when taken in conjunction with the accompanying drawings.
Referring now to the drawings in which like numerals indicate like parts throughout the several views,
As generally indicated in
As indicated in
Turning now to the drawings,
As indicated in
As depicted in
The minimum or variable engagement adjustment 28 generally can include a setscrew, pin or similar device that is received within, and is moveable vertically along the bore or channel 31 of the sleeve 29 in the direction of arrows 32 and 32′. The variable engagement adjustment 28 may be secured within the sleeve 29 so as to prevent loss of the variable engagement adjustment screw or similar device 28, and further may be restricted to permit only adjustments within a predetermined safe setting range for the trigger engagement setting. Still further, while the variable engagement adjustment 28 generally is shown as a setscrew or other threaded fastener received within a sleeve or cylinder, other adjustment mechanisms other than a threaded screw and/or sleeve also can be used as long as such adjustment mechanisms enable a substantially precise and consistent adjustment of the trigger engagement setting.
As further indicated in
Thereafter, the trigger engagement setting for the trigger assembly further can be adjusted down to a minimum engagement setting of typically approximately 0.01 inches by adjustment or movement of the variable engagement adjustment 28. The variable engagement adjustment 28 generally is designed to be moved in the direction of arrows 32 and 32′ along the bore or inner channel of the sleeve 29 so as to permit reduction of the trigger engagement setting generally by about 50%, up to approximately 100% of the preset or maximum engagement setting, with a minimum value of the variable engagement setting generally being fixed at or around approximately 0.01 inches for safety considerations.
As further illustrated in
A spring 47 generally is received within the rear end of the bore 42, with a first or proximal end 48 of the spring being at least partially received within the bore 42 so as to be engaged by the setscrew 41. A second or distal end 49 of the spring is received in recess 51 formed within the trigger body 15 so as to secure the distal end of the spring against lateral or vertical movement. As the set screw 41 is moved in the direction of arrow 46 along its bore 42, it causes compression of the spring 47, while conversely, moving the set screw in the direction of arrow 46′ releases the compression on the spring. As a result, as the compression of the spring is increased, the amount of force required to move the trigger during a trigger pull is correspondingly increased, while releasing the compression on the spring lightens or reduces the amount of force needed for a trigger pull so the trigger pull can be varied due to user preference for reduction of lock time and sharper response of the trigger. The trigger adjustment further can be fixed with a minimum trigger pull amount so as to limit the adjustment of the trigger pull by a user to within a predefined range.
Additionally, there is provided a trigger block adjustment 60 for adjusting or setting the engagement between the trigger and a safety mechanism 61 upon actuation of the safety mechanism to prevent movement of the trigger. The trigger block adjustment mechanism 60 generally is provided or mounted within the rear arm portion 18 of the trigger body 15, as shown in
The trigger block adjustment mechanism 60 is shown here as including a set screw 70 that is received within a bore 71 formed within the rear trigger arm portion 18, although it will also be understood that other types of similar adjustment devices also can be used. The set screw 70 generally is adjustable by threaded movement thereof along the bore 71 in the direction of arrows 72 and 72′ so as to adjust the distance at which a head portion 73 of the set screw 70 projects above the rear trigger arm portion 18 to a desired point at which a lower portion 76 of the safety arm 62 will be engaged at a tight point of contact to ensure substantially minimal or no movement of the trigger upon engagement of the safety mechanism 61.
By providing such varying adjustments of the trigger assembly or fire control mechanism, the present invention enables the manufacture of various component parts of the trigger mechanism such as the safety and trigger with a wider range of manufacturing tolerances, instead of requiring a highly precise fit between the safety mechanism and trigger, which thus enables a lower cost to manufacture such parts, while still providing a precise, tight engagement between the safety mechanism and trigger of the fire control. Further, once set, the trigger block adjustment typically will be permanently affixed, such as by welding or the use of a sealing material such as a resin, such as lock-tight, or other similar material. It is also possible to allow the trigger block adjustment to remain unfixed, as needed or desired for maintenance or other adjustment of the fire control mechanism after extensive use.
Although the present invention has been described with various embodiments, it is understood that the modifications and variations may be utilized without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the appended claims and their equivalents.
