Attachment Interface for Recoil Environments

This non-provisional application is a continuation-in-part of U.S. Non-provisional application Ser. No. 18/889,282, filed on Sep. 18, 2024, which claims benefit of U.S. Provisional Application Nos. 63/670,690 (filed on Jul. 12, 2024) and 63/592,519 (filed on Oct. 23, 2023), all of which are incorporated by reference herein.

This non-provisional application also claims benefit of U.S. Provisional Application No. 63/673,654, filed on Jul. 19, 2024, which is incorporated by reference herein. This non-provisional application is also a continuation-in-part of U.S. Non-provisional application Ser. No. 18/480,451, filed on Oct. 3, 2023, which claims benefit of U.S. Provisional Application Nos. 63/417,236 (filed on Oct. 18, 2022) and 63/412,758 (filed on Oct. 3, 2022), all of which are incorporated by reference herein.

Some firearms have modular grip assemblies. In one example of a modular grip assembly, a backstrap attaches to the grip frame. A grip characteristic of the firearm (e.g., grip size or grip profile/shape) may be changed by using the same grip frame in combination with a different backstrap.

In firearms with modular grip assemblies, a backstrap may attach to a back of the grip frame using a rotatably-driven fastener. However, in recoil environments, recoil forces may cause the backstrap to loosen over time, as recoil forces are transmitted into the grip frame as well as into other components of the grip assembly. While it may be possible to still use a firearm with a grip having some “play,” any play in the grip is undesirable and highly noticeable (given that an operator's hand is in contact with it). To re-tighten the rotatably driven fastener, the operator of course needs to have a rotatable driving tool (e.g., a screwdriver) available.

To reduce loosening, an operator may install a threaded rotatably driven fastener with an adhesive, such as Loctite®. However, this approach may be undesirable for reasons explained in U.S. patent application Ser. No. 18/480,451, filed on Oct. 3, 2023, which is herein incorporated by reference.

Besides the possibility of loosening from recoil, each fastener or its fastener hole may create a discontinuity in a surface of the grip assembly. For example, a fastener to attach the backstrap (or its fastener opening if it is countersunk) may create a discontinuity on a grip surface of the backstrap. This discontinuity may affect grip effectiveness (which may be impactful in, say, wet conditions), grip comfort, accumulation of debris, and/or appearance (a manufacturer may be constrained in the kind of aesthetic grip designs it can develop, when there is a requirement for a discontinuity in the grip surface). The discontinuity may have the most negative impact when it is located at a mid-back position of a backstrap, which many are as this location may enable use of only one fastener for the backstrap.

Any of the problems explained above with regard to a backstrap can affect other grip parts, such as magwells. A magwell (e.g., a flared detachable magwell) may couple to a bottom of a grip frame, and may act as a guide for loading a magazine into the magazine well of the firearm. A magwell (e.g., a flared detachable magwell) may increase the entry area of the magazine well.

illustrates a sectional view of the grip frame assembly described in more detail in U.S. patent application Ser. No. 18/480,451, filed on Oct. 3, 2023, which is herein incorporated by reference. The grip frame assembly includes a grip partmountable to a modular grip assembly of a firearm (not shown), and another part(e.g., a magwell in this example) coupled to different part of the grip frame. A threaded holefor a rotatably-driven fastenerA extends through magwelland into backstrap.

The rotatably-driven fastenerA may have features to prevent loosening due to recoil forces, e.g., self-locking threads along its length and/or a tapered head, as described in more detail in the '451 application. However, other advantages of this arrangement over the known arrangements that use a threaded rotatably driven fastener will be apparent to one of ordinary skill in the art (for example, the entire back surface of the separable grip may be free of discontinuities such as fastener heads or counter openings, which may provide a better grip for an operator of the firearm and allow a manufacturer to make a more unique/desirable appearance of the grip assembly).

The various advantages of the grip frame assembly described by the '451 application notwithstanding, it may still be desirable to provide some further grip assembly arrangements in which there is no requirement for a discontinuity on the part of the grip assembly to make contact with the operator's hand when operating the firearm.

illustrates an exploded isometric view of a frame assemblyfor a firearm, according to various embodiments. The frame assemblyincludes a grip frame, a first separable part(e.g., a grip part, such as a backstrap), a second separable part (e.g., a grip accessory such as a magwell), and a plunger assembly (e.g., plungerand spring).

The grip surface of the separable part(e.g., the back exterior surface) does not have any fastener discontinuities for attachment features (e.g., no fastener or fastener opening on the back exterior surface). This may improve grip when operating the firearm, such as in wet conditions.

Regarding the magwell, instead of a fastener or fastener opening discontinuity, it has a push tool access port, which may have a diameter that is smaller than the head of a typical fastener used in a grip assembly. This push tool portmay receive a push tool, as opposed to a rotatable driving tool that may be required to install rotatably driven fasteners. One example of a push tool usable with the portmay be a paper clip or small wire.

The backstrapmay be backwards compatible with known grip frames, and may be mounted to the grip framein place of an original backstrap (not shown). The backstrapmay have an interface (e.g., one or more channels) to mate with the extrusionsof the grip frame. In various embodiments, the backstrapmay have other interface features to mate with known grip frames, such as a retention pin hole (not shown) to receive a retention pin (not shown) of the frame. In these embodiments, the backstrapmay define a retention pin hole (not shown) to receive a retention pin of the interface of the grip frame. The backstrapmay be mounted to the grip framein place of an original backstrap (not shown) using the same retention pin.

Similarly, the magwellmay be backwards compatible with known grip frames. For example, the backstrapmay have an interface(e.g., a lip) to slidingly mount onto a grooveof the grip frame.

In various embodiments, the backstrapmay have any interface to mate with any grip frame interface now known (e.g., used on known grip frames), or later developed. The interface on the back of the grip frame may be an attachment interface (such as one or more channels) to mate with the interface of the grip frame(e.g., the extrusion).

Referring now to, a user may wish to remove the backstrapfor a number of reasons. For example, the grip assembly may not properly fit the hand of an intended operator. A backstrap of a different size (e.g., smaller, larger, differently shaped, etc.) may produce a better overall grip for the intended operator. Alternatively, a user may wish to replace the backstrapfor any other reasons such as a different material backstrap, a different atheistic design, an alternative textured pattern, or the like, or combinations thereof.

The backstrapmay be easily removed from the frame assemblyby an operator, using the plunger assembly. In a first stage of disassembly, a user may insert a push toolinto the portto at least partially collapse the spring, as illustrated in. The push toolmay be any tool that fits into the port, such as an improvised tool (in some embodiments, a paper clip may be used as a tool to at least partially collapse the spring).

With the springpartially collapsed, referring tothe magwellmay be moved slidingly forward relative to the backstrap. This forward sliding may cause the interfacesandofto be slidingly released from one another. The forward movement may also cause a protrusion on one or the backstrapand the magwellto be removed from a corresponding opening on the other of the backstrapand the magwell. Referring to, in this example the openingis defined by the magwelland the protrusionis defined by the backstrap. It may be possible and practical to reverse this arrangement in other embodiments (with a protrusion defined by a magwell). Also, in this embodiment the openingis an undercut opening (e.g., a dovetail groove to receive a dovetail), but in other examples an opening may be some other kind of undercut opening to receive some other kind of protrusion (e.g., a T-slot).

Referring to now, with the magwellpositioned from the forward movement described previously, the plunger assembly may be removed from the plunger assembly opening(e.g., the plungerand springmay be removed). The user may then remove the backstrapfrom the grip frame(), such by moving the backstrapdownward to slidingly release it from the grip frame.

With the backstrapremoved, a user may then attach some other separable part that may have a same mounting interface as backstrapto the grip frame(). For example, the user may install a different backstrap that may be larger or smaller than the backstrap.

To install the different backstrap, the user may mount it on the grip frame() by, say a sliding upward movement. The user then may install the same plunger assembly into a plunger assembly opening on the different backstrap. The user may then slidingly move the interface() of the magwellinto the interfaceof the grip frame.

While a typical reason to remove the magwelland backstrapmay be to use a different backstrap, it should be appreciated that one may remove the magwellregardless of whether the backstrapis removed. It may be possible to provide another grip accessory, such as a magwell with a different well geometry or some other grip accessory having an attachment interface similar to the magwell. As one example, a glass breaker accessory may be provided with the same attachment interface as the magwell. The magwellmay be replaced with the glass breaker accessory, and the glass breaker accessory could retain the backstrapin a similar way that the magwellretains the backstrap. Any grip accessory or other grip part, now known or later developed, may include an attachment interface similar in various respects as the described attachment interface of the magwell.

Referring now to, when the springis in a default state (e.g., a state that is less collapsed than the partial collapsing needed to move the magwellforward relative to the backstrap), part of the plungermay be located in the hole. The holemay be a bore having a vertical sidewall, but this is not required (in other examples, a holecould be a faceted hole with plural flat faces, a hole having a sloped sidewall(s), etc.)

The part of the plungerlocated in the holemay include a tapered nose. An entire length of the taper to make contact with a sidewall of the hole, in some embodiments. In the illustrated embodiment, a slope of the taper may be similar to a slope of the holeto provide this contact. In this example, the end of the taper nose is flat; however, this is not required (in one example, the end of the plungermay have a dimple or other depression to receive a push tool inserted into the port). Another part of the plunger, e.g., an opposite endof the plunger as illustrated, may have an outer diameter that is less than an inner diameter of the spring.

The illustrated embodiment of a firearm grip accessory assembly (e.g., magwelland backstrap) is compatible with an original SIG P365® X MACRO® grip frame. However, other embodiments of a firearm grip accessory assembly including a magwell having an interface to mate with a corresponding interface of a backstrap may be made compatible with grip frames of any other firearm.

In the illustrated embodiment of an accessory assembly, the separable part of the modular grip assembly is a backstrap. However, in other embodiments, an accessory assembly may include any separable part, now known or later developed, that is mountable with a grip frame of a modular grip assembly.

Although the grip accessory in the illustrated embodiments is a magwell, in other embodiments any grip accessory mounting interface described herein may be used to attach any kind of grip accessory, now known or later developed, to attach to firearm grip.

In the illustrated embodiment, the spring of the plunger assembly is a metal spring. However, this is not required. In various embodiments any type of spring, now known or later developed, may be used in place of the illustrated metal spring. A spring may include any object to generate a spring force, such as any elastic object that stores mechanical energy. Also, any retention device described herein (e.g., a plunger) may be a part that is separable from a spring or may be integrally formed with the spring.

In some embodiments, a grip accessory may retain a separable part on a grip frame (e.g., prevent the separable part from sliding off the grip frame). However, this is not required. The plunger assembly described herein and/or the undercut attachment structures, or any other feature(s) described herein, can be used with a self-retaining separable part (e.g., a separable part retained on the grip frame using its own one or more rotatably driven fasteners). In self-retaining embodiments, it may be possible for the any retention system described herein to retain a grip accessory and/or redundantly retain the separable grip part.

In the illustrated embodiment modular grip assembly includes two separable parts; however, this is not required. In other embodiments, a retention system (e.g., including a spring and a plunger) may be used to retain a single part. In one example, the grip surface of the backstraps described herein may be an integral part of a grip frame. In these embodiments, the protrusion() and/or the holemay be defined by the grip frame. A separable part having any features of any magwell described herein may be used in combination with such a grip part. This may allow a manufacturer to produce, say, a magwell that is usable with a wide variety of grip frames (e.g., grip frames that have a separable part such as a backstrap, and grip frames in which the grip surface is integrally formed on the grip frame).

Some known plunger assemblies are non-canted. For example, U.S. Pat. No. 11,747,100, granted on Sep. 5, 2023 (which is incorporated by reference herein) describes a spring loaded plunger described with respect toof the '100 patent in which a center axis of the spring and/or the stud is at a right angle with an axis along with the retained part that is slidingly removed (e.g., a center axis of the removable cap described with respect toof the '100 patent).

Referring again toof the present application, a canted retention system is used. As illustrated in, a center axis of the retention system including the springand the retention deviceforms an oblique angle with an axis along which at least one of the retained parts (e.g., magwell) is slidingly removed. Stated another way, inthe magwellmoves along a horizontal axis of the illustration, whereas the plunger assembly moves along an axis that is tilted with respect to a vertical axis of the illustration. A center axis of the holeis also at an oblique angle relative to a center axis of the openingthat receives the tapered nose.

The tapered nosemay have a shape of a truncated cone. As the retained part (e.g., the magwell) is pushed along its axis of movement (e.g., along a horizontal axis in this embodiment) by an operator's force, the truncated cone shaped section of the retention device is urged by the spring force into the hole. However, the holehas a non-sloped sidewall (e.g., a shape of a cylinder), so the truncated cone shaped section moves downwardly until line contact is provided between the sloped surface of the truncated cone and the non-sloped sidewall of the hole(e.g., a cylindrically shaped bore in this example).

The line contact urged by the canted spring force in turn provides a rearward contact force that urges the retained part (e.g., magwell) in a rearward direction (e.g., orthogonal to the center axis of the bore, as shown by arrow). Furthermore, since the only contact is on a single side (e.g., a rearward sidewall) of the opening, all the contact force is in one direction (e.g., a rearward direction in this example). Essentially, once a user pushes the retained partinto the illustrated position, the retained partis locked into place. Referring to, this locates the front part of the lipin the front part of the groove. This may eliminate the highly noticeable slight “play” that is present in other retention arrangements used in recoil environments (in which a front part of lip on the separable part may not completely locate within a front part of a mating groove on the grip frame even when other parts of the lip are completely located in the mating groove).

Even if the user does not push the retained partall the way (e.g., a few thousands of an inch short), any forward force applied to the separable part will not move the separable part relative to the base due to the plunger. Optimally, any rearward force applied to the separable part during operation or carry will allow the plungerto be urged further into the opening, further engaging the retention system and thus further seating a front part of the lipinto a front part of the groove.

A groove and lip are not required to use the canted retention system described herein. In other embodiments, a base part (e.g., a grip frame) may have a flared section where the separable part may have a ledge to mate with the flared section. The canted retention system may be used in combination with any interface (e.g., an interface for sliding coupling parts), now known or later developed.

A retention system including at least the features of the tapered retention device and the canted spring force described above can be used in any recoil environment to retain one part to another part without requiring a threaded rotatably driven fastener.

When a firearm provides a modular grip assembly, such as a firearm including a backstrap described with reference to, a threadless region for attaching a grip attachment thereon may be provided on the modular attachment. For example, in the embodiment described in, a slideable attachment interface is provided on the modular attachment (e.g., a protrusionis provided on the backstrap, in the illustrated embodiment). A grip attachment (e.g., magwell) can then be used in combination with the existing frame (which may be an original frame or an aftermarket frame that is similar to the original frame).

One approach for providing a grip attachment usable with “non-modular” frame would be to replace the existing frame with a new design that incorporates a slideable attachment interface. For instance, it may be possible and practical to provide a new frame that includes a slideable attachment interface similar to the slideable attachment interface of the backstrapof. However, it may be desirable to allow users to utilize a grip attachment in combination with their original frame.

Some embodiments described herein provide a grip attachment that may be used with a wide variety of grip assemblies (e.g., usable with a non-modular frame and any other type of non-modular firearm part). In this approach, a kit of parts may be provided, which allows a user to utilize a grip attachment in combination with an existing frame (even in cases where the existing frame does not have modular features).

Referring briefly to, a frame without modular features has been retrofitted to include a slideable attachment interface, similar to the slideable attachment interface on the backstrapof. In various embodiments described herein, this retrofit can be completed without drilling, damaging, or otherwise altering the existing frame. Also, in various embodiments a part including the slideable attachment interface may be removably coupled to the existing frame, e.g., a user can couple and uncouple the part including the slideable attachment interface without adhesives, without damaging the existing frame, and/or without damaging the that includes the slideable attachment interface.

It is known that molding, casting, and other manufacturing techniques used to form parts, have various process requirements to ensure a well-formed part (e.g., a well-formed molded part, a well-formed casted part, etc.) These process requirements may include a maximum thickness of material. For example, if a manufacturer attempts to manufacture a frame using molding, the manufacturer ought to provide design features that avoid thick volumes of material. Typically, this is accomplished by providing a hollow. Also, generally speaking, a part that is formed may have one or more other process artifacts of the formation process, such as tool openings to remove manufacturing tooling (e.g., an opening through which the core is pulled out during manufacturing).

It is known that many existing frames typically include at least one of these process artifacts. For instance, looking at the bottom of some frames, one will see, rearward of the magazine well, a D-shaped opening, and a thin wall of material between the D-shaped opening and the magazine well. This “hollow” was provided by the manufacturer's original design to address molding process requirements, and as such it may be referred to herein as a molding process artifact.

Various embodiments described herein provide a kit of parts, which include an expandable body to wedgingly install in a hollow or other process artifact of an existing part such as a frame. This expandable body may provide a point of attachment for a slideable attachment interface, such as a female dovetail or corresponding male feature, a female T-slot or corresponding male feature, or some other undercut opening or corresponding male feature.

The frame having the expandable body installed therein may have one or more threadless regions, including the expandable body's threadless region having the slideable attachment interface. These one or more threadless regions may be used to couple a grip attachment, such as a magwell having a threadless region, to the frame. Due to the use of the threadless regions, like other embodiments described herein, the grip attachment (e.g., the magwell) may remain fixably attached over time (e.g., may not loosen over time as recoil forces are transmitted into the grip frame as well as into other components of the grip assembly, as is observable with some known magwells).

In the embodiment illustrated in, the assemblyincludes a grip attachment(e.g., a magwell) retained on a grip partusing an expandable body(illustrates an exploded isometric view of the assembly, andillustrates an isometric view of the assemblywith the grip attachmentseparated therefrom).

Referring to, to attach the grip attachment(e.g., the magwell) to the frame, an operator/installer may removably couple the expandable bodyto the frame. Then, the operator/installer may slide the grip attachmentonto the frame(the frameand the grip attachmentmay have a sliding attachment interfaces similar to any sliding attachment interfaces described herein). Once the grip attachmentis slid on (e.g., into a predefined position), a plunger similar in any respect to any plunger described herein may drop into the plunger into a plunger engagement holedefined by the grip attachment.illustrates an isometric view of the assembly ofin an assembled state without showing the frame() for case of illustration.

To remove the grip attachment(e.g., the magwell), an operator/installer may insert a tool into a tool port (which may be similar to the tool port described with reference toherein, but is not visible in the views of), which allows the operator/installer to slidably remove the grip attachmentoff the frame. The operator/installer may also uninstall the expandable bodyfrom the cavity, if desired, using opposite steps as installation.

illustrates a side view of the grip attachmentof.illustrates a rear end view of the grip attachmentof. The tool access portis illustrated in. In this example, the tool access portis canted at an angle similar to a cant of any canted retention system described herein. However, the tool access portmay be canted in a different amount, or not canted, in other examples.