Patent Description:
The following background information may present examples of specific aspects of the prior art (e.g., without limitation, approaches, facts, or common wisdom) that, while expected to be helpful to further educate the reader as to additional aspects of the prior art, is not to be construed as limiting the present invention, or any embodiments thereof, to anything stated or implied therein or inferred thereupon.

Typically, a firearm is a portable gun that discharges projectiles that are driven by the action of an explosive force caused by pressure during the discharge of ammunition. An automatic firearm includes a firearm that continues to load and fire cartridges from its magazine as long as the trigger is depressed and until the magazine is depleted of available ammunition.

It is known in the art that a bolt is the part of a repeating, breech-loading firearm that blocks the rear of the chamber while the propellant burns and moves to facilitate loading of cartridges from the magazine. Automatic and semi-automatic firearms are provided with a bolt catch which retains the bolt in the open position upon firing the last round in a magazine. The bolt is thereafter manually released after a fresh magazine is inserted, so that a round is chambered in readiness for firing.

Typically, locking the bolt carrier group in its rearward position allows the user to look into the ejection port of the firearm and inspect the chamber for a live round or to clear an operational malfunction. Once a loaded magazine is inserted into the receiver, or a malfunction is cleared, the user needs an efficient means for releasing the bolt carrier group from the locked-back position.

Other proposals have involved restricting automatic recoil of the bolt or bolt carrier group. The problem with these bolt catch devices is that they do not convert automatic rifles to single-shot mode by automating the restriction of forward recoil by the bolt. Even though the above cited bolt catch devices meets some of the needs of the market, an automatic firearm single-shot bolt catch assembly that utilizes a tensioned spring operational with a bolt catch, such that tension from the spring works to displace a plate in the bolt catch to a catch position, which restricts the recoiling bolt carrier group in linear path of the firearm, is still desired.

<CIT> describes a mechanism for a repeating firearm that includes a bolt catch configured to restrict motion of the bolt carrier. The bolt catch is also configured to engage with the trigger when the bolt carrier is released to restrict motion of the trigger and prevent discharge of the firearm.

The invention is a firearm single-shot bolt catch assembly according to claim <NUM> and its associated method of operation according to claim <NUM>. Illustrative embodiments of the disclosure are generally directed to a firearm single-shot bolt catch assembly and method of operation. The automatic firearm single-shot bolt catch assembly uses a tensioned spring that operates with a bolt catch. The tension from the spring works to pivotally articulate a plate in the bolt catch to a catch position, which restricts the recoiling bolt carrier group in linear path of the firearm. The tension from the spring presses the plate upwardly into the linear path to restrict the passage of, and hold, the bolt carrier group towards the rearward end of the firearm. This restriction of movement inhibits automated recoiling responses from the bolt carrier group, consequently creating a single-shot mode by disabling the automated firing sequence of the firearm. Applying force to a lever that forms in the bolt catch overcomes the spring bias to displace, or pivotally articulate, the plate out of the linear path followed by the bolt carrier group.

In one non-limiting embodiment, firearm single-shot bolt catch assembly provides a bolt catch operational with a firearm. The bolt catch comprises a plate and a lever. The plate is defined by a plate first end, a plate second end, a top edge, and a bottom edge forming a spring cavity. The lever is defined by a lever first end, a lever second end, and a middle region forming an aperture. The middle region of the lever joins with the plate in a generally coplanar relationship.

The automatic firearm single-shot bolt catch assembly further comprises a spring that detachably fits inside the spring cavity at the bottom edge of the plate. The spring is tensioned to bias the plate into a linear path followed by a bolt carrier group of a firearm. This restrictive disposition of the plate restricts the bolt carrier group at a rearward end of the firearm. Furthermore, applying force to the lever pivotally articulates the plate out of the linear path followed by the bolt carrier group.

One objective of the present invention is to reconfigure an automatic rifle pattern from an automatic or semi-automatic mode, to a single-shot mode.

Another objective is to adapt an automatic or semi-automatic firearm to be legal.

Yet another objective is to enable facilitated installation of a bolt catch into the receiver slot on the side of the firearm.

Another objective is to enable facilitated release of the bolt carrier group from a linear path in the firearm through application of force on the lever with the thumb.

Yet another objective is to provide a spring cavity in the bottom edge of the plate and a tensioned spring that fits into the spring cavity.

Yet another objective is to provide an inexpensive to manufacture automatic firearm single-shot bolt catch assembly.

Other systems, devices, methods, features, and advantages will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims and drawings.

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:.

The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word "exemplary" or "illustrative" means "serving as an example, instance, or illustration. " Any implementation described herein as "exemplary" or "illustrative" is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. For purposes of description herein, the terms "upper," "lower," "left," "rear," "right," "front," "vertical," "horizontal," and derivatives thereof shall relate to the invention as oriented in <FIG>. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims.

At the outset, it should be clearly understood that like reference numerals are intended to identify the same structural elements, portions, or surfaces consistently throughout the several drawing figures, as may be further described or explained by the entire written specification of which this detailed description is an integral part. The drawings are intended to be read together with the specification and are to be construed as a portion of the entire "written description" of this invention as required by <NUM> U.

In one non-limiting embodiment of the present invention presented in <FIG>, a firearm single-shot bolt catch assembly <NUM> and method <NUM> of operation allows a firearm <NUM> to convert from an automatic mode to a single-shot mode by restricting movement of a bolt carrier group <NUM> that recoils forward from a rearward end <NUM> of a firearm <NUM> after discharging a projectile. Assembly <NUM> and method <NUM> works to automatically restrict bolt carrier group <NUM> to the rearward end <NUM> of firearm <NUM> with a spring tensioned plate <NUM>; and then enables manual release of the bolt carrier group <NUM> to a release position <NUM> through application of force on a lever <NUM>, so as to enable single-shot discharges. This single-shot mode allows a banned automatic firearm <NUM> to operate as a legal firearm <NUM>.

As <FIG> references, firearm single-shot bolt catch assembly <NUM>, hereafter "assembly <NUM>" leverages the tensional forces inherent in a spring <NUM> with a bolt catch <NUM> operational in the firearm <NUM>. The tension from spring <NUM> works to displace, or pivotally articulate, a plate <NUM> in the bolt catch <NUM> to a catch position <NUM>, which restricts bolt carrier group <NUM> from recoiling forward along a linear path <NUM> that forms longitudinally along the rearward end <NUM> firearm <NUM>. It is this restriction of automated recoil that converts firearm <NUM> into a single-shot mode.

Specifically, as shown in <FIG>, the tension from spring <NUM> displaces, or pivotally articulates, the plate <NUM> upwardly into linear path <NUM> to restrict bolt carrier group <NUM> at the rearward end <NUM> of firearm <NUM>. This restriction of movement inhibits automated recoiling responses from bolt carrier group <NUM>, consequently creating a single-shot mode by disabling the automated firing sequence of the firearm <NUM>. Furthermore, by applying force to a lever <NUM> in the bolt catch <NUM>, the spring bias on plate <NUM> is overcome, enabling pivotal articulation of the plate <NUM>, out of the linear path <NUM>, and into a release position <NUM>. Release position <NUM> enables forward recoil by bolt carrier group <NUM>.

As illustrated in <FIG>, assembly <NUM> is especially useful for converting a banned automatic firearm <NUM> to a legal single-shot firearm <NUM>. Those skilled in the art will recognize that multiple variations of automatic firearms have been developed to remove banned features. Examples of banned features include telescoping/foldable stocks, excessive grips, bayonets, and muzzled and threaded barrels. Examples of banned firearms are shown in <FIG>, illustrating: an automatic firearm <NUM> having a folding stock <NUM>; an automatic firearm <NUM> having a second handgrip <NUM>; an automatic firearm <NUM> having a capacity to attach a magazine <NUM> outside the pistol grip, and a shroud (not shown) that is attached to or completely encircles the barrel and that permits the shooter to hold the firearm with the non-textured grip surface hand without being burned.

Furthermore, the automatic firearm <NUM> may have a telescoping stock (not shown); an automatic firearm having a protruding pistol grip <NUM>; an automatic firearm <NUM> having a thumb spring cavity stock (not shown); an automatic firearm <NUM> having a threaded barrel <NUM> that can accept accessories, such as flash suppressors, muzzle brakes, and compensators; and an automatic firearm <NUM> having a bayonet mount <NUM>. The present disclosure works to adapt the banned automatic firearm <NUM> described above, to a legal single-shot firearm <NUM> by restricting forward recoiling of the bolt carrier group, and consequently limiting the number of shots fired in rapid succession.

Looking now at the relationship between assembly <NUM> and firearm <NUM> in <FIG>, the assembly <NUM> comprises a bolt catch <NUM> that is insertable through a receiver slot <NUM> in the side <NUM> of firearm <NUM>. Bolt catch <NUM> is operational in a linear path <NUM> of firearm <NUM> followed by bolt carrier group <NUM>. The essence of assembly is to pivotally displace bolt catch <NUM> in and out of path <NUM> followed by bolt carrier group <NUM> through use of a tensioned spring <NUM> that biases bolt catch <NUM> into the path <NUM>, and a thumb-controlled lever <NUM> that displaces bolt catch <NUM> from the path <NUM>.

In one non-limiting embodiment, bolt catch <NUM> comprises substantially two components fixedly joined together - a plate <NUM> and a lever <NUM>. Lever <NUM> is generally elongated and flat, forming a surface for the thumb or other digits of the hand to manipulate bolt catch <NUM>. Thus, lever <NUM> functions primarily to enable manipulation of bolt catch <NUM>.

Looking again at <FIG>, lever <NUM> may be defined by a first end <NUM> having a textured grip surface <NUM>, a middle region <NUM> forming an aperture <NUM>, and a second end <NUM>. In one embodiment, known in the art, a pin <NUM> may pass through aperture <NUM> to enable insertion and attachment of bolt catch <NUM> to a receiver slot <NUM> forming on the side <NUM> of the firearm <NUM>. Pin <NUM> may include a cotter pin, a role pin, and a fastening mechanism known in the art.

Plate <NUM> forms integrally with the lever <NUM>, forming a unitary component to effectively restrain and release the bolt carrier group <NUM> along linear path <NUM> of firearm <NUM>. In one embodiment, the plate <NUM> is generally flat and coplanar with lever <NUM>. Plate <NUM> functions primarily to restrict linear displacement of bolt carrier group <NUM> at the rearward end <NUM> of firearm.

In one non-limiting embodiment, plate <NUM> may be defined by a top edge <NUM> forming a lip <NUM>, a bottom edge <NUM>, a plate first end <NUM>, and a plate second end <NUM>. The lip <NUM> at top edge <NUM> of plate <NUM> engages receiver slot <NUM> in firearm <NUM> to hold bolt catch <NUM> in place. Plate second end <NUM> fixedly joins with middle region <NUM> of lever <NUM> in a generally coplanar relationship. In one embodiment, plate <NUM> and lever <NUM> may be welded together to withstand recoil forces caused from discharge of firearm <NUM>.

As shown back in <FIG>, bottom edge <NUM> of plate <NUM> forms a spring cavity <NUM>. Spring cavity <NUM> may be approximately in the center area of bottom edge <NUM> of plate <NUM>. Bottom edge <NUM> of plate <NUM> has sufficient width to enable spring cavity <NUM> to form therein. In one embodiment, spring cavity <NUM> is dimensioned about <NUM>" deep X <NUM>" diameter. Though spring cavity <NUM> may have other dimensions in other embodiments.

In one non-limiting embodiment, assembly <NUM> further utilizes a spring <NUM> having a spring first end <NUM> and a spring second end <NUM>. In one embodiment, spring second end <NUM> tapers out and is wider than spring first end <NUM>. Spring first end <NUM> is sized and dimensioned to at least partially fit into the spring cavity <NUM> at bottom edge <NUM> of plate <NUM>. Spring second end <NUM> buttresses the trough at the bottom of the slot of the receiver. In one embodiment, spring <NUM> is about <NUM>" X <NUM>".

In one non-limiting embodiment, spring <NUM> may have a tension. Those skilled in the art will recognize that an elastic object, such as a coil or spring, is used to store mechanical energy. When a coil or spring is compressed or stretched from its resting position, it exerts an opposing force approximately proportional to its change in length. The rate or spring constant of the coil or spring is the change in the force it exerts, divided by the change in deflection of the spring. Thus, the tension, or change in the force of spring <NUM> is sufficient to pivotally articulate, or press, bolt catch <NUM>, and specifically the plate <NUM>, upwardly, substantially into the linear path <NUM> of the bolt carrier group <NUM> in a catch position, as shown in <FIG>. The tension from spring <NUM> also works to retain bolt carrier group <NUM> at the catch position until further operator action.

Thus, as the tensioned spring <NUM> pushes off the bottom of the trough in the receiver slot, the plate <NUM> of bolt catch <NUM> restricts passage of bolt carrier group <NUM>. This inhibits the automatic responses from bolt carrier group <NUM>, which creates a single-shot mode, and disables the automated firing sequence of firearm <NUM>.

While forcibly retained in the catch position, bolt catch <NUM> restricts linear displacement of bolt carrier group <NUM> along path <NUM>. Bolt carrier group <NUM> cannot move towards forward end of firearm <NUM> to enable access to another round without operator action, i.e., release of the bolt carrier group <NUM> from the receiver slot <NUM> in firearm <NUM>. This is illustrated in <FIG>, where assembly <NUM> does not release bolt carrier group <NUM> without fully releasing bolt catch <NUM> from receiver slot <NUM>. This process creates, in essence, a single-shot firearm.

In order to fire a subsequent round, the bolt carrier group <NUM> must be released from the receiver slot <NUM>. This is accomplished by applying force to the lever <NUM>, so as to pivotally articulate the plate <NUM> out of the linear path <NUM>. In some embodiments, the lever first end <NUM> may have a textured grip surface <NUM> to facilitate manipulation of lever <NUM> in such a manner. Only after plate <NUM> is displaced to release position <NUM> by manipulation of lever <NUM>, may a subsequent projectile be discharged by firearm <NUM>. Release position <NUM> is illustrated in <FIG>.

In one non-limiting embodiment, plate first end <NUM> of plate <NUM> attaches in an articulated manner to a catch depression <NUM> that is disposed in the receiver slot of the firearm <NUM>. The catch depression <NUM> is known in the art, forming an opening in the receiver slot <NUM>. In another embodiment, a catch spring <NUM> and a catch plunger <NUM> are fitted into catch depression <NUM>. Catch plunger <NUM> serves to fasten catch spring <NUM> into catch depression <NUM>. In this manner, bolt catch <NUM> pivots about the catch plunger <NUM> between the release position <NUM> and the catch position <NUM>.

Those skilled in the art will recognize that a bolt catch is a firearm component usually under the bolt carrier group that engages the bolt after the last round is fired. When the last round is fired, the bolt comes back to complete the cycle and eject the round. As the bolt reaches the rearward position of the firearm, it is caught by a pin or lever of the bolt catch. The bolt catch holds the bolt in a rearward position, thereby allowing the magazine to be replaced and the following round to be chambered without charging the action. In the present disclosure, bolt catch <NUM> includes a lever <NUM> release mechanism that allows bolt catch <NUM> to be pivotally articulated from a catch position <NUM> to a release position <NUM>.

Thus, the purpose of a bolt catch on any firearm is to retain the principal members of the bolt or bolt carrier mechanism in a rearward position. The rear-hold position is desirable as a safety measure to allow an unobstructed view of the chamber of a firearm; to provide access to the chamber area for cleaning or clearing an obstruction, or other maintenance; as a signal to the operator that the magazine is empty; and to provide a means for rapid reloading, by holding the bolt carrier group <NUM> to the rearward end <NUM> of firearm <NUM> while the empty magazine is removed and a new magazine is installed.

For purposes of the present disclosure, the function of bolt catch <NUM> is to stop displacement of bolt carrier group <NUM> when pushed upward by the follower of an empty magazine (<FIG>). Bolt catch <NUM> enables bolt carrier group <NUM> to be locked to the rearward end <NUM> of firearm <NUM> after expending a magazine so that a new one can be inserted and bolt catch <NUM> pushed back to the release position to fire another round. For this, after the last shot has been fired, the cartridge loader normally pushes the magazine onto the bolt catch lever and pivots it or pushes it into the movement path of the bolt, i.e. into the catch position.

The bolt carrier group <NUM>, which first returns after firing then meets the bolt catch <NUM> when it again moves forward, and the two block each other in a reciprocal manner. After a full magazine has then been inserted, the bolt <NUM> can again be released through a manual actuation of the lever <NUM>, i.e. the bolt catch <NUM> again ends up in the release position <NUM> (<FIG>). The bolt carrier group <NUM> then guides a cartridge into the chamber as it moves forward, and the firearm <NUM> is again ready for discharging. It is this last step that the assembly <NUM> restricts bolt carrier group <NUM>.

To highlight the advantages of assembly, <FIG> illustrates a prior art bolt catch <NUM> that operates substantially the same as the assembly <NUM> taught above, except that there is no use of the spring <NUM> that biases the plate <NUM> to the catch position <NUM>. Nonetheless, the prior art bolt catch <NUM> still utilizes a plate <NUM> and an integrally formed lever <NUM> that are pivotally held into the receiver slot <NUM> with a pin <NUM>, a catch spring <NUM>, and a catch pin <NUM>. The primary difference being that a spring <NUM>, as taught above, does not insert into the bottom edge of the plate <NUM>. Thus, the present disclosure configures the banned automatic firearm <NUM> described above, to a legal single-shot firearm <NUM> by restricting forward recoiling of the bolt carrier group with a plate <NUM> from the bolt catch <NUM>, and consequently limiting the number of shots fired in rapid succession.

<FIG> illustrates a flowchart of an exemplary method <NUM> for operation of a firearm single-shot bolt catch assembly in a firearm. Method <NUM> may include an initial Step <NUM> of inserting a bolt catch into a linear path of a firearm, the bolt catch comprising a plate and a lever. The method <NUM> may further comprise a Step <NUM> of fitting a spring into a spring cavity forming in the bottom edge of the plate, the spring comprising a tension. A Step <NUM> includes biasing, through the spring tension, the plate into a linear path that forms in the firearm.

In some embodiments, a Step <NUM> comprises sliding a bolt carrier group towards a rearward end of the firearm. A Step <NUM> includes discharging the firearm to displace a bolt carrier group along the linear path towards the bolt catch. In some embodiments, a Step <NUM> may include restricting, with the plate, forward recoil by the bolt carrier group, in a catch position. A Step <NUM> comprises pivotally articulating the lever to overcome the spring bias. A final Step <NUM> includes enabling forward release of the bolt carrier group, in a release position, for subsequent discharges by the firearm.

Although the process-flow diagrams show a specific order of executing the process steps, the order of executing the steps may be changed relative to the order shown in certain embodiments. Also, two or more blocks shown in succession may be executed concurrently or with partial concurrence in some embodiments. Certain steps may also be omitted from the process-flow diagrams for the sake of brevity. In some embodiments, some or all the process steps shown in the process-flow diagrams can be combined into a single process.

Claim 1:
A firearm single-shot bolt catch assembly for restricting the movement of a firearm bolt carrier group, the assembly comprising:
a bolt catch (<NUM>) comprising a plate (<NUM>) and a lever (<NUM>), the plate defined by a plate first end (<NUM>), a plate second end (<NUM>), a top edge (<NUM>), and a bottom edge (<NUM>), and the lever (<NUM>) defined by a lever first end (<NUM>), a lever second end (<NUM>), and a middle region (<NUM>) forming an aperture (<NUM>), the middle region (<NUM>) of the lever being joined with the plate in a generally coplanar relationship; and
a spring (<NUM>) having a spring first end (<NUM>) and a spring second end (<NUM>);
whereby the bolt catch (<NUM>) is configured to be pivotally articulated between a catch position and a release position;
the spring (<NUM>) is tensioned to bias the bolt catch (<NUM>) upwardly into the catch position;
the lever (<NUM>) is arranged such that applying force to the lever (<NUM>) displaces the plate (<NUM>) from the catch position to the release position;
characterised in that:
a spring cavity (<NUM>) is formed in the bottom edge (<NUM>) of the plate (<NUM>) and a first end of the spring is fitted inside the spring cavity at the bottom edge of the plate.