Compact flat magazine spring

A flat spring for firearm magazines has a one-piece unitary body with end half-coils at opposite ends and interior coils in a repeating arrangement between the end half-coils. Each of the interior coils includes an upper half-coil and a lower half-coil, each extending between outer tips on opposite sides of the spring body. Increasing and staggering the half-coil lengths, adjusting the radii of the outer tips and shaped matching the end half-coils and upper and lower half-coils within the magazine housing all contribute to a flat magazine spring that uses all available space within a firearm magazine to effectively reduce the number of coils and material thickness so that the compressed spring height is at its absolute minimum, thereby allowing for maximum space for ammunition.

BACKGROUND OF THE INVENTION

This non-provisional patent application is based on provisional patent application Ser. No. 62/857,989 filed on Jun. 6, 2019.

FIELD OF THE INVENTION

The present invention relates to a magazine spring as used in automatic and semiautomatic pistols and rifles, and more particularly an improved one-piece magazine spring that allows additional space for bullet storage by requiring less space for the compressed spring, thereby accomplishing a more compact design.

DISCUSSION OF THE RELATED ART

Typical magazines for firearms contain a single oval spring wound from round wire. Because of the length and force required from the spring, a conical style cannot be used. When compressed, the coils (i.e., winds) of the spring stack upon one another. In a typical wire magazine spring, much of the space available for the spring is wasted as the spring is formed in the shape of an oval and contains a large unused area in its center. This makes for a very inefficient design as it relates to utilizing the space within the magazine. While far less common, there have also been magazine springs made of a flat strip material that is formed into an accordion shape. This type of spring has also suffered from inefficient use of the available space within the magazine housing.

Firearm magazines come in many different sizes, shapes, and configurations. For example, the follower may ride at an angle within the magazine housing, the magazine housing itself may be angled or the base of the magazine housing may be angled relative to the front and rear surfaces. The magazine may also be larger at the bottom and taper to a smaller size at the top. A typical magazine spring of the prior art does not effectively utilize the area within the irregular shapes of the magazine housing, especially when the spring is compressed. Magazine springs compress into a generally symmetric vertical stack though the space within which it is compressed may be of an irregular angled shape leaving valuable unused space that could be utilized to contain spring material (as part of the spring). Additional spring material would increase the length and or the force of the spring per coil which ultimately would allow fewer coils. It may also allow a thinner spring material. Fewer coils and thinner material equals shorter compressed height of the spring. When the compressed height of the spring is reduced, there is more room in the magazine for additional ammunition.

Firearms, particularly pistols, are often miniaturized for easier carry and concealment. Typical compact firearm designs often sacrifice bullet capacity to accomplish miniaturization especially in pistols where the bullets are stored in a magazine within the grip. Whether a miniaturized firearm or not, it is preferred that the magazine house as many bullets as possible while maintaining as small a size as possible. There is a need for an improved single magazine spring design that allows for more bullet storage within the same amount of space without sacrificing performance.

SUMMARY OF THE INVENTION

The present invention is directed to a flat firearm magazine spring formed in a shape that compresses to a fraction of the height (fully compressed) of a typical wire spring or prior flat springs, while maintaining appropriate forces. In a novel way, this spring takes advantage of all volume available within the magazine housing when the magazine is full (i.e., fully loaded with bullets) and the spring is fully compressed, as well as when the magazine is empty and the spring is extended. The result is utilization of maximum spring material within the irregularly shaped available space of firearm magazines, which is unlike any prior magazine spring. This design provides a considerably shorter compressed spring without sacrificing the free length or force of the spring which allows for more bullets in the magazine in a simple single spring design.

GENERAL PARTS DESCRIPTION

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the several views of the drawings, the compact flat magazine spring of the present invention is shown according to several embodiments thereof and is generally indicated as1throughout the drawings. The spring1is formed as a one-piece, unitary body having repeating interior coils5each consisting of an upper half-coil6and a lower half-coil7that are formed together in a general accordion shape. There are two end half-coils8, one at each the beginning end and the terminating end of the spring1. Each interior half-coil6,7consists of two opposing arc shapes9,10that are tangent or near tangent to one another. The half-coils6,7are attached together at each outer tip12with the smallest radius that the chosen material will allow on at least one side. The end half-coils8differ from the interior half-coils6,7in that they are formed as a single arc shape extending outward from the spring rather than two opposing arc shapes9,10thus maximizing the free length of the spring1. The formed shape of the spring1is designed so that, upon compression, equal and opposing forces are created that flatten the curved half-coils6,7,8. When the spring is fully compressed, every half-coil6,7,8of the spring is nearly flat so that the compressed height of the spring stack is as short as possible.

It should be noted that when referring to the lengths of the upper and lower half-coils6,7, the half-coil length is the distance measured between the outer tips on opposite sides of the spring body at the opposite ends of each of the upper and lower half-coils6,7. This is different than the coil length5awhich, as seen inFIGS. 2 and 4A, is the distance between adjacent outer tips on the same side of the spring body when the spring body is in the relaxed state.

In some embodiments, the upper half-coil6is a different overall length than the lower half-coil7in each coil5which creates an angled stack when the spring is compressed, as seen inFIGS. 3 and 4, for example. The desired forward or rearward angle of the compressed spring stack would determine which half-coil would be longer. The amount of angle of the compressed spring stack would be determined by the difference in length between the upper half-coil6and the lower half-coil7. Refer toFIGS. 4 and 6-6Afor an example. This angled stack allows the half-coils6,7to be lengthened into areas under the follower2that are otherwise vacant spaces15in prior art designs (seeFIGS. 5 and 5A) when the spring is compressed. Longer half-coils results in greater coil lengths5a. This additional coil length5acontributes to a spring design with fewer coils5, but equal free (uncompressed) length compared to prior spring designs. Depending on other factors, the gain in coil length5acould also mean reduced material thickness, while maintaining desired spring performance. Fewer coils5and less material thickness equals less room necessary for the compressed spring1and more room for ammunition4. For example,FIGS. 5 and 5Aillustrate a prior art wire spring in the fully compressed state at the base of the magazine3, and below the follower2, which creates vacant space15. In comparison,FIGS. 6 and 6Aillustrate the flat spring1of the present invention, in accordance with the embodiment ofFIG. 4, wherein the equal radii of the outer tips on opposite sides of the spring body results in a uniform, level spring stack arrangement and the varying lengths of the upper half-coils versus the lower half-coils results in the slanted stack configuration. The result is a significantly lower overall height of the spring stack in the fully compressed state compared to the wire spring of the prior art seen inFIGS. 5-5A, while also filling in the vacant space15as a result of the slanted spring stack arrangement. As noted above, the longer half-coils results in greater coil lengths5a, which contributes to a spring design with fewer coils5, but equal free (uncompressed) length compared to prior art spring designs. As seen in the comparison of the prior art wire spring inFIGS. 5-5A, compared to the flat spring1of the present invention shown inFIGS. 6 and 6A, the significantly reduced height of the compressed spring stack of the spring1inFIGS. 6 and 6Aallows for an additional bullet4to be loaded into the same size magazine3. This additional space, allowing for the additional bullet4, is a result of the design of the flat spring1that maximizes the available space while reducing the overall height of the compressed spring stack.

Referring toFIGS. 1-3 and 7-7A, some embodiments of the flat spring1provide the radii at the outer tips12to be minimized down one side of the spring while the radii of the outer tips12is larger on the other side of the spring where room in its compressed state permits. More specifically, referring toFIGS. 1-3, the radii of the outer tips12aon the right side of the spring is greater than the radii of the outer tips12bon the left side of the spring1. By increasing the radii at the outer tips12a, the two half-coils6,7that the outer tip12aconnects are spread further apart, therefore adding to the coil lengths5a. Also, the larger radius spreads the bending stress at the outer tips12aover a larger material length. This increases the potential angle between half-coils on one side of the spring where the larger radii are used. When the angle between half-coils6,7is increased, the coil length5ais also increased. As with the longer half-coils6,7described in the prior paragraph, the longer coil lengths5acreated by a greater angle between half-coils6,7contributes to a spring design with fewer coils5but equal or greater free (uncompressed) length compared to prior designs. The larger radius at the outer tips12ais sized so that the compressed spring1fills the maximum amount of space under the follower2when the magazine is full and the spring is fully compressed, as seen inFIGS. 7 and 7A.

The shape matched version of the spring1is seen inFIG. 1andFIGS. 8-9. In these embodiments, the spring1is shaped so that the uncompressed spring in an empty magazine fits within the shape of the magazine housing3. In magazines that taper from large at the bottom to small at the top, as is common in many double stack pistol applications, the flat spring1would also taper to match. The corners at each end of the outer tips12may contain a shape matching radius17if necessary to match the interior shape of the magazine housing3. This shape matching feature maximizes the spring material width within the magazine housing3. By increasing the spring width (i.e., the widths of the half-coils6,7and8) the spring material thickness can be reduced without sacrificing spring performance. Reduced spring material thickness contributes to minimizing the compressed height of the spring1.

Increasing and staggering the half-coil6,7lengths to create an angled stack, adjusting outer tip12radii to maximize the distance and angle between half-coils6,7and shape matching the half-coils6,7and8of the uncompressed spring (FIGS. 1, 8 and 9) within the magazine housing3are design features that contribute to a flat magazine spring design that uses all available space within a firearm magazine to effectively reduce the number of coils5and material thickness so that the compressed spring height is at its absolute minimum, thereby allowing for maximum space for ammunition.