The present invention relates generally to a shoulder-fired firearm primary and secondary recoil attenuator adapted to mount on the butt of a shoulder-fired firearm. More so, the invention teaches a shoulder-fired firearm recoil attenuator that mounts to the butt of the firearm and absorbs both the primary and secondary recoil impulses when the firearm is fired; the molecular structure being oriented as a result of compression of the material (shape engineering) such as a copolymer elastomer and shape engineered to exhibit time-dependent strain that provides recoil damping; whereby the copolymer viscoelastic damper comprises a material molecular structure that compresses a minimum of 40% of normal dimensions during recoil and returns to normal dimensions; whereby the configuration and performance of the damper is tailorable through use of a design database.
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:
Like reference numerals refer to like parts throughout the various views of the drawings.
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
An illustrative embodiment of a shoulder-fired firearm primary and secondary recoil attenuator 100 is referenced in
As illustrated in
The damper 104a, 104b may be fabricated from a viscoelastic copolymer elastomer material having a hollow body elastomer construction, as illustrated in
The damper 104a, 104b may be shape-engineered to exhibit a time-dependent strain that provides the double recoil cushioning while also protecting against wear and tear. The viscoelastic material of the damper 104a, 104b may be manufactured using a damper design database that enables customizable dimensions for the damper 104a, 104b. The shape engineering process may not, however, change the composition of the material of the damper 104a, 104b, but rather the shape of the damper 104a, 104b and the shape of the force-travel curve of the damper 104a, 104b, as shown in
In one aspect, a shoulder-fired firearm primary and secondary recoil attenuator 100 may include:
A shoulder-fired firearm primary and secondary recoil attenuator, the attenuator comprising:
In another aspect, the attenuator 100 may be developed via a damper design database which enables tailorable shape and dimensions for the damper 104a, 104b.
In another aspect, the mount plate 102a may transfer recoil load from the firearm butt 202 to the damper 104a, 104b and to the shoulder plate 102b, respectively.
In another aspect, the distance between the mount plate 102a and the shoulder plate 102b may form a plate space 112 which allows the damper 104a, 104b to compress.
One objective of the present invention is to reduce the dynamic load on the shoulder of a shoulder-fired firearm user while discharging the firearm 200, caused by the recoil of the firearm 200.
Another objective is to improve the ballistic characteristics of the shoulder-fired firearm 200 by reducing recoil forces during discharge.
Another objective is to dampen both the primary recoil caused by the acceleration of a bullet traveling through a firearm barrel and a secondary recoil caused by the ejection of the gases exiting the firearm barrel.
Another objective is to facilitate distinct spring rates for primary recoil caused by the acceleration of a bullet traveling through a firearm barrel, and a secondary recoil caused by the ejection of the gases exiting the firearm barrel.
Another objective is to dampen the recoil characteristics of a firearm without use of a spring or moving mechanical parts.
Another objective is to absorb recoil energy in less weight and space than hydraulic, urethane, or rubber recoil absorbing devices.
Another objective is to absorb more recoil energy in a smaller space, for a minimal impact on component packaging, so that minimal firearm stock modification is required.
Another objective is to construct the viscoelastic material from a proprietary molecular orientation process that greatly enhances the strength and durability of the damper 104a, 104b, up to 10 times than that for rubber and 20 times that for urethane.
Another objective is to provide a simple installation of the attenuator 100 on the firearm butt 202 on a firearm 200 which may be accomplished with at least one plate fastener 118a, 118b passing through at least one aperture 106a, 106b in the mount plate 102a.
Those skilled in the art will recognize that firearm recoil pads extend rearward from the rear of a rifle stock. The pads are often configured to absorb recoil impulse when the firearm is fired. Many of these pads are constructed from closed cell foamed viscoelastic materials. Further, many pads are constructed from urethane and other TPE (thermoplastic elastomers) viscoelastic materials. These materials are prone to fail if compressed more than approximately 38% of their original length. The present invention is easily installed on the butt 202 of a shoulder-fired firearm 200 and constructed from a viscoelastic material having a hollow body elastomer configuration and may further be compressible to more than fifty percent of the original dimensions, length or volume.
As
Turning now to
As referenced in
Looking now at
In any case, the damper 104a, 104b may be the primary component that compresses in response to discharge of the firearm 200 to absorb some or most of the primary and secondary recoil impulses from the firearm 200. The damper 104a, 104b may be compressible in response to a primary recoil caused by the acceleration of a bullet traveling through the barrel of the firearm 200, and a secondary recoil caused by ejection of the gases exiting the barrel. Compression of the damper 104a, 104b may occur in two distinct impulses, with the higher spring rate typically occurring during primary recoil and the lower spring rate typically occurring during secondary recoil.
In some embodiments, the damper 104a, 104b may be fabricated from a viscoelastic material having a hollow body elastomer configuration. The energy absorption of the damper 104a, 104b may be accomplished via internal resistance to strain from shear between the polymer molecular chains in the damper 104a, 104b.
Those skilled in the art will recognize that a viscoelastic damper 104a, 104b may be fabricated substantially from a viscoelastic material, which is a material that exhibits both viscous and elastic characteristics when undergoing deformation. In essence, the viscoelastic damper 104a, 104b may act like a spring and damper system, and in certain cases may approximate the performance of an ideal hydraulic damper.
Furthermore, the typically hollow body elastomer configuration of each damper 104a, 104b of the present invention may be shape-engineered to exhibit a time-dependent strain. The viscoelastic damper 104a, 104b may have a unique material molecular structure. Through the shape engineering process, the molecular structure may be oriented such that under deformation, the damper 104a, 104b retains its integrity after every recoil.
As discussed above, the viscoelastic material may be compressible to more than 50% of the dimensions, length or volume of the damper 104a, 104b. Evidence of the compressibility of the dampers 104a, 104b is shown in
The Force vs. Stroke curve of the graph 700 illustrates the ability of the attenuator 100 to absorb energy. Essentially, the molecular structure of the elastomer damper 104a, 104b resists deformation as internal friction is generated between the polymer chains in the damper 104a, 104b. There is thus hysteresis between the compression curve 702 and the return curve 704, corresponding to the absorbed energy or energy converted to heat, as illustrated in
The shape engineering of the viscoelastic material of the damper 104a, 104b may include a process of shaping the viscoelastic material to the desired shape between the mount plate 102a and the shoulder plate 102b. The shape engineering may orient the molecular structure in such a way as to achieve specific performance in the force vs travel performance and hysteresis. The damper design database may include numerous saved data points so as to enable multiple shapes of the viscoelastic material to be achieved.
Looking now at
Thus, graph 800 shows the different spring rates and hysteresis between the attenuator designs. For example, curve A is a very short damper before deformation but is still compressed >40%; thus, it has much less travel than damper D. All of the dampers 104a, 104b may be compressed more than 40% to create the shape-engineered design. On the graph 800, the stroke axis is in terms of displacement and not a percentage of initial length.
In yet another advantage that can be achieved by adjusting the shape of the viscoelastic material, the damper 104a, 104b may be configured to absorb energy in less weight and space than hydraulic, urethanes, or rubbers. Also, the damper 104a, 104b may absorb a larger quantity of energy in a smaller space, for a minimal impact on component packaging. In this manner, minimal firearm stock modification is required. These multiple shapes are possible because the damper 104a, 104b is constructed from a proprietary molecular orientation process that greatly enhances the strength and durability of the damper 104a, 104b, which in some embodiments can be up to 10 times that of rubber and 20 times that of urethane. The shape engineering process may change the shape of the damper 104a, 104b and the shape of the force-travel curve, as shown in
Thus, the present invention teaches an actuator 100 that has many advantages over conventional damper designs. This is depicted in the graph 1000, shown in
As shown in the graph 1000 of
Another advantage provided by the attenuator 100 of the present invention is that the damper 104a, 104b may form a solid state recoil pad which absorbs maximum quantities of recoil energy while requiring little or no maintenance. For example, the damper 104a, 104b may not require steel coil springs or hydraulic fluids, and thus, exhibits significantly fewer failure modes. Yet another advantage provided by the attenuator 100 of the present invention is the easy installation of the mount plate 102a to the butt 202 of the firearm 200, unlike conventional hydraulic recoil pads.
Despite its significant compression, the damper 104a, 104b has a long life expectancy due to its unique shape-engineering capacity. This life expectancy is significantly longer and more resilient than conventional hydraulic pads, which are mechanical and thus require maintenance. Furthermore, the damper 104a, 104b is lightweight and may be fabricated primarily of lightweight foams and plastics. By offering such simplicity, very few components are needed for the attenuator 100, necessitating a limited number of failure modes.
In typical application of the attenuator 100, the mount plate 102a may be attached to the firearm butt 202 of the firearm 200. In some embodiments, this may be accomplished by extending attenuator mount fasteners (not illustrated) through the respective apertures 106a, 106b in the mount plate 102a and threading the attenuator mount fasteners into respective fastener openings (not illustrated) in the firearm butt 202. In other embodiments, the mount plate 102a may be attached to the firearm butt 202 using clips, clamps brackets and/or other suitable attachment mechanism.
Preparatory to firing the firearm 200, a firearm shooter (not illustrated) may place the mount plate 102a of the attenuator 100 against the shooter's shoulder. The shooter may then fire the firearm 200. As it travels through the barrel of the firearm 200, the bullet creates a primary recoil which causes the firearm butt 202 to travel rearwardly against the damper 104a, 104b. Accordingly, as the mount plate 102a travels toward the shoulder plate 102b, the damper 104a, 104b is compressed and may shorten at least about 50% of its length. The shortening damper 104a, 104b may absorb some or most of the primary recoil pressure of the primary recoil and transmit the remaining primary recoil pressure against the shoulder plate 102b. The shoulder plate 102b may, in turn, apply a minimal magnitude of the primary recoil pressure against the shoulder of the firearm shooter. The damper 104a, 104b may then recoil back to the pre-compression length as the mount plate 102a travels away from the shoulder plate 102b.
As the gases from the ejected bullet subsequently travel through and are ejected from the forearm barrel, the gases create a secondary recoil which causes the firearm butt 202 to travel rearwardly against the damper 104a, 104b. The mount plate 102a thus travels toward the shoulder plate 102b and the damper 104a, 104b is compressed to absorb the secondary recoil pressure. The shortening damper 104a, 104b may absorb some or most of the secondary recoil pressure and transmit the remaining secondary recoil pressure against the shoulder plate 102b. The shoulder plate 102b may, in turn, apply a minimal magnitude of the secondary recoil pressure against the shoulder of the firearm shooter. The damper 104a, 104b may then again recoil back to the pre-compression length as the mount plate 102a travels away from the shoulder plate 102b. Because the viscoelastic material of the damper 104a, 104b may be shape-engineered to exhibit time-dependent strain, the damper 104a, 104b may have distinct spring rates in response to the primary recoil impulse and the secondary recoil impulse.
Referring next to
Application of the attenuator 300 may be as was heretofore described with respect to application of the attenuator 100 in
These and other advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims and appended drawings.
There are polymer additives and processes that increase molecular chain length that lead to improved cold temperature performance and increases energy absorption.
Because many modifications, variations, and changes in detail can be made to the described preferred embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalence.
This application claims the benefit of U.S. provisional application No. 62/599,257, filed Dec. 15, 2017 and entitled SHOULDER-FIRED FIREARM PRIMARY AND SECONDARY RECOIL ATTENUATOR, which provisional application is hereby incorporated by reference herein in its entirety.
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