Toggle Trigger
A trigger mechanism for a firearm which has a light trigger pull, reliably contains the high forces of the firing pin spring and achieves this with a mechanism which is simple and with few parts. A toggle linkage prevents the firing pin retainer releasing the firing pin whilst still allowing a light pull. It contains no internal sear and no pins within the toggle mechanism. It is adjustable for variations in manufacturing and can cater for various levels of trigger pull force. It realizes considerable economies for production, assembly and repair without sacrificing functionality.
This invention relates to a trigger assembly for firearms including target rifles. The mechanism provides for a light trigger pull whilst greatly simplifying the mechanism.
Description of Prior ArtTo enhance accuracy a great many shooters, desire the lightest trigger pull possible. However, the trigger must contain the high force of the firing pin spring to prevent inadvertent firing. Usually this force is contained by a sear type of arrangement. A sear may be described as a physical impasse being a block, other analytic or primitive shape or part, aligned with a mate to block movement until such time as it is moved. A trigger that is set too light or with too little sear engagement can have a tendency to go off prematurely. Containing the high force of the firing pin spring is thus at odds with the idea of a light trigger pull.
Referring to
Referring to
The sear is under great load and thus these triggers have both a heavier than desirable pull and have lost motion or creep when in use. To reduce the effect of this load and reduce creep, the sear and its mate must be both precisely geometrically aligned to provide only an iota of engagement and are often highly polished, usually by hand, resulting in intricate and time-consuming work.
Other alternate designs are difficult, expensive and geometrically complex, with a relatively high number of moving parts and are therefore complicated to manufacture. They predominantly use a large number of pins within said mechanisms and the precise alignment thereof requires unnecessarily tight tolerances and are thus arduous to produce, assemble and repair.
BRIEF DESCRIPTION OF THE INVENTIONThe invention overcomes these difficulties by being able to facilitate a light trigger pull, prevent premature firing, eliminate lost motion and significantly reduces excess complexities in manufacturing, the combination of these factors being the consummate goal of shooters and manufacturers. The trigger internal parts are contained between two outer sheets creating a chassis. The internal parts of the trigger consist of two toggles being a lower toggle, and a free-floating upper toggle.
Other parts are a trigger shoe, a torsion spring and a firing pin retainer. The invention does not rely on an internal sear nor any pins between the lower toggle, free-floating upper toggle and firing pin retainer. This is accomplished by having the lower toggle and free floating upper toggle aligned to create a geometrically rigid structure beneath the firing pin retainer. The combination of the lower toggle and free-floating upper toggle may also be described as the toggle linkage. This toggle linkage rests upon a trigger shoe with an adjustable screw at a point along its length. The trigger shoe and adjustable screw provide a stop for the toggle linkage. A torsion spring provides a pre-load to keep the toggle linkage against the adjustable screw of the trigger shoe and also provides a force to reset the mechanism for the next cycle.
When the trigger shoe is pulled it rotates and causes the adjustable screw to push the toggle linkage beyond its tipping point. At this stage the force of the firing pin spring via the firing pin which itself is pushing on the firing pin retainer causes the toggle linkage to collapse. This allows the firing pin retainer to release the firing pin and the firing pin moves forwards to fire the firearm.
When the trigger shoe is released and the firing pin is moved rearwards during reloading of the firearm, the torsion spring resets the lower toggle, the upper free-floating toggle and the firing pin retainer to their original positions ready for the next cycle.
With regards to firearms, the invention is able to facilitate a light trigger pull, prevent premature firing and importantly, significantly reduce excess complexity in manufacturing assembly and repair. Throughout this description the term forward, forwards, front or fore shall refer to the orientation of the firearm and trigger towards the direction of the barrel of the firearm. Throughout this description the term rearward, rearwards, rear or aft shall refer to the orientation of the firearm and trigger towards the direction of the butt of the firearm.
With reference to
With reference to
With reference to
With reference to
With reference to
With reference to
With reference to
Note that the ends of the Upper Free-Floating Toggle are pointed, nearly pointed or slightly radiused thus reducing bearing force to minimal levels. Note also that the Torsion Spring Upright is acting on the Lower Toggle close to the Lower Toggle Screw and thus has a low leverage force. This means that even though the Lower Toggle and Upper Free-Floating Toggle linkage was quite rigid in
With reference to
With reference to
With reference to
Undertravel Screw can be adjusted to set Trigger Shoe in the correct position while the trigger is on a cocked or ready to fire condition. This adjustment allows for broader manufacturing tolerances and for wear.
Overtravel Screw can be adjusted to limit the travel of Trigger Shoe too much beyond that necessary for Lower Toggle and Upper Free-Floating Toggle to go beyond the Tipping Line, that point at which the Toggle Linkage collapses and the Firing Pin fires the firearm. This adjustment allows for broader manufacturing tolerances and for wear.
Trigger Shoe Adjustment Screw can be adjusted to control the position of the Lower Toggle and Upper Free-Floating Toggle versus the Tipping Line. With Trigger Shoe adjusted to the desired position when the trigger is in the cocked or ready to fire condition by Undertravel Screw, the Trigger Shoe Adjustment Screw can then be adjusted forwards until the Tipping Line is exceeded, Toggle Linkage collapses and the Firing Pin moves forwards. The Trigger Shoe Adjustment Screw can then be finely adjusted rearwards to the point where the Toggle Linkage and Firing Pin Retainer just holds the Firing Pin in the cocked position. The Trigger Shoe Adjustment Screw may then be screwed further rearwards from this point to increase the rearwards bias of the Toggle Linkage, enhance the rigidity of the Toggle Linkage in the cocked position and thus prevent premature firing. Important is that in this cocked position the Toggle Linkage rests against the Trigger Shoe Adjustment Screw which therefore also acts as the rearward mechanical stop for the Toggle Linkage. Thus, the Trigger Shoe Adjustment Screw acts in direct mechanical communication between Trigger Shoe and Toggle Linkage. This mechanical train of Trigger Shoe to Trigger Shoe Adjustment Screw to Toggle linkage being that which will ultimately fire the firearm. Thus, being imbedded directly in this train, when adjusted, Trigger Shoe Adjustment Screw acts directly and without any intermediary upon and within this train. Being imbedded in this way, any adjustment made to Trigger Shoe Adjustment Screw, directly controls both the rearwards bias of the Toggle linkage to control premature firing whilst also completely avoiding any introduction of any lost motion of the Trigger Shoe when the trigger is being used. This ease and singularity of adjustment within the invention greatly enhances functionality and usability. Furthermore, this adjustment also allows for broader manufacturing tolerances and allows for wear.
Firing Pin Retainer Adjustment Screw can be adjusted for dimensional variations in Lower Toggle and Upper Free-Floating Toggle part sizes. In this case the Firing Pin Retainer Adjustment Screw can be adjusted to remove unnecessary free-play within this linkage and thus this adjustment also allows for broader manufacturing tolerances and for wear.
Note that in this invention all these adjustments are arranged so that they may be made from underneath the trigger and thus with the trigger still in situ in the firearm.
Note that there are no pins located between the Lower Toggle, Upper Free-Floating Toggle or Firing Pin Retainer. Whereas pins require precise alignment and therefore tight manufacturing tolerances of components in two, if not three dimensions to achieve fit between parts or within mechanical part trains, inventing a design which has a fully self-constrained Upper Free-Floating Toggle, free of pins, coupled with the ability to easily adjust the Toggle Linkage removes the necessity of tight manufacturing tolerances thus greatly easing production, assembly and repair. This adds to the novelty of the invention.
Note that solely using a Lower Toggle and Upper Free-Floating Toggle to lock the Firing Pin Retainer in place means that no internal sear is necessary in this invention. This removes geometric complexity of design, eases manufacturing tolerances and negates the necessity of hand polishing a sear and its mate to reduce trigger pull weight negating arduous, intricate and time-consuming work. This adds to the novelty of the invention.
Note that the parts of this invention are uniquely designed such that Side Sheets are able to be profile cut from sheet and internal parts are able to be profile cut from plate. Coupled with the aforementioned ability within the invention for inherent adjustments due to manufacturing variations to be made, profile cutting such as this versus intricate machining of parts, as is common in contemporary triggers, greatly simplifies and speeds manufacturing and this adds to the novelty of the invention.
Claims
1. A trigger assembly for use with firearms comprising:
- a) Two sheets of material which act as an external chassis for internal parts;
- b) A lower toggle which is pivotally attached to said sheet chassis;
- c) A firing pin retainer which is pivotally attached to said sheet chassis;
- d) An upper toggle being free floating and self-constrained between said lower toggle and said firing pin retainer with said upper toggle having pointed, near pointed or slightly radiused ends;
- e) A toggle linkage being the combination of said lower toggle and upper toggle;
- f) A geometric tipping line being a straight line between each end of said toggle linkage;
- g) Said toggle linkage being a rigid set when arranged ante said tipping line;
- h) A trigger shoe which is pivotally attached to said sheet chassis;
- i) A trigger shoe adjustment screw attached to said trigger shoe;
- j) Said trigger shoe adjustment screw being in operational communication with said toggle linkage;
- k) A torsion spring being grounded at one end with the other end applying force to said toggle linkage;
- l) Whereby when said trigger shoe is pulled causing said trigger shoe adjustment screw to move said toggle linkage forward and collapse said toggle linkage as toggle linkage is moved post said tipping line;
- m) Whereby when said toggle linkage collapses said firing pin retainer rotates downward releasing firing pin and firing the firearm;
- n) Whereby said trigger shoe adjustment screw may be adjusted to control bias between said toggle linkage and said tipping line;
- o) Whereby adjustment of said trigger shoe adjustment screw introduces no lost motion.
2) The trigger assembly in accordance with claim 1 further comprising of an overtravel adjustment screw for said trigger shoe.
3) The trigger assembly in accordance with claim 1 further comprising of an undertravel adjustment screw for said trigger shoe.
4) The trigger assembly in accordance with claim 1 further comprising of a firing pin retainer adjustment screw for adjustment of free-play in said toggle linkage.
5) The trigger assembly in accordance with claim 1 in modified form comprising said torsion spring installed in an inverted position to increase force of trigger pull.
6) The trigger assembly in accordance with claim 1 wherein the external chassis sheet may be profile cut from sheet material;
7) The trigger assembly in accordance with claim 1 wherein internal parts being said lower toggle said upper toggle said trigger shoe and said firing pin retainer may be profile cut from plate material;
8) The trigger shoe adjustment screw of claim 1 being able to be adjusted from beneath with the trigger in situ in the firearm;
9) The adjustment screw of claim 2 being able to be adjusted from beneath with the trigger in situ in the firearm;
10)The adjustment screw of claim 3 being able to be adjusted from beneath with the trigger in situ in the firearm;
11)The adjustment screw of claim 4 being able to be adjusted from beneath with the trigger in situ in the firearm.
Type: Application
Filed: Jul 31, 2018
Publication Date: Feb 6, 2020
Inventor: Martin Dieter Lobert (Edge Hill)
Application Number: 16/051,460