Patent Publication Number: US-5291679-A

Title: Magazine with indicator

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to magazines for firearms, and specifically to indicators showing the number of bullets remaining in a gun magazine. 
     Guns are usually constructed to fire a plurality of bullets, often by employing a removable magazine that contains a plurality of bullets (as used herein, &#34;bullets&#34; includes &#34;cartridges&#34;). Typically, a magazine comprises a hollow body configured to accept a plurality of bullets and having a bullet aperture through which bullets are loaded into the magazine and through which bullets are urged to enter the gun&#39;s firing chamber. The magazine is usually provided with a follower that is urged towards the bullet aperture, usually by a spring, so that a new bullet is urged towards the bullet aperture after a bullet is removed from the magazine. 
     It is very desirable to be able to determine the number of bullets in a magazine so that the user knows how many shots he has left. Of course, this can be determined by knowing the capacity of the magazine when full, and counting the number of bullets that have been fired. However, guns are often used in stressful situations, such as in gun battles, and it is therefore very easy to forget the number of rounds that have been fired. In such circumstances, it is also impossible to eject the magazine in order to count the number of bullets remaining. Also, the user might not be able to look at any visual indicator of the number of bullets that may be left in the magazine, either because of the circumstances or because there is not enough available light. 
     Many patents have been issued relating to indicators for magazines. 
     U.S. Pat. No. 2,377,661 to Baker discloses a magazine having a flexible ribbon joined to the follower and having an indicator means attached, where the position of the indicator means along a slot informs the user of the number of cartridges within the magazine. 
     U.S. Pat. No. 1,202,768 to Arnold discloses an indicator tape having indicating characters that are selectively displayed in a frame as ammunition is discharged. 
     U.S. Pat. No. 382,455 to Butler discloses a bar having gear teeth on an edge and a series of figures intended to be visible one at a time through an opening. 
     U.S. Pat. No. 3,828,568 to Sakewitz discloses a magazine having a plate marked with numbers that moves past two windows in the grip of a gun to indicate the number of cartridges remaining. 
     U.S. Pat. No. 2,620,582 to Stukas discloses a magazine having a slot on the side which would show the number of cartridges remaining. 
     U.S. Pat. No. 4,587,756 to Jakubaschk, et al., discloses a magazine having an indicator that follows a spring as it uncoils. 
     A number of other patents have been issued for indicator means for guns, including U.S. Pat. No. 343,471 to Maynard, U.S. Pat. No. 502,389 to Whitten, et al., U.S. Pat. No. 784,786 to Gottardi, U.S. Pat. No. 1,326,234 to Veeder, U.S. Pat. No. 1,332,936  to Veeder, U.S. Pat. No. 2,569,995 to Kapsa and U.S. Pat. No. 4,558,626 to Bartolles. 
     Of the above mentioned references, only U.S. Pat. No. 784,786 to Gottardi provides a means for determining the number of cartridges remaining without looking at the gun. Further, except for U.S. Pat. No. 2,377,661 to Baker, all of the above references require structures in the gun to cooperate with the magazine for the indicator to function. Thus, it would be impossible to provide existing guns with the indicators disclosed in the above references (except for Baker) unless the guns were modified to provide the requisite cooperating structures. This prevents retrofitting existing guns with these indicators by merely providing replacement magazines (except for Baker). 
     Accordingly, it is an object of this invention to provide an indicator that simply and reliably indicates the number of bullets remaining in a magazine. 
     It is also an object of this invention to provide such an indicator that can be used quickly, easily and reliably without the user looking at the magazine or the gun. 
     It is a further object of this invention to provide such an indicator that is self-contained in a magazine and that does not require cooperating structure on the gun so that the indicator can be used on existing guns merely by replacing the magazine. 
     It is a still further object of this invention to provide such an indicator that can be easily retrofitted to existing magazines. 
     It is a still further object of this invention to provide such an indicator that is simple and inexpensive to manufacture. 
     BRIEF SUMMARY OF THE INVENTION 
     These and other objects are obtained by a magazine that comprises a hollow body having a bullet aperture and an indicator aperture, a follower slidably mounted in the hollow body, and an elongated indicator member attached to the follower, extending through the indicator aperture and projecting outside the body by an indicator length so that displacement of the follower causes a change in the indicator length. Preferably the indicator length is very short if the magazine is empty. The indicator length therefore will correspond to the approximate distance that the follower has been displaced from the bullet aperture, which in turn will correspond to the number of bullets in the magazine. Preferably, also, the indicator member comprises a flexible strand that preferably includes a plurality of knots, knobs, beads, slots, holes or other configurations (all hereinafter collectively referred to as &#34;knots&#34;) that can be sensed by touch, spaced along the indicator length at predetermined intervals that are fixed so that when a number of bullets is inserted in the magazine, an equal number of knots projects outside the magazine. Thus, by counting the number of knots, the user can determine the number of bullets remaining in the magazine. The user can count the number of knots by feel, which would allow determining the number of bullets remaining without looking at the gun. In more elaborate embodiments, each knot could correspond to a predetermined number of bullets (such as 2, 3 or 5) or the configurations of the knots could vary and be coded so that a user could determine the number of bullets merely by touching the knot closest to the gun. 
     The short length of the indicator when the magazine is empty and the flexibility of the material used for the indicator allows for field stripping (i.e., disassembly, cleaning and reassembly in the field) without the need for additional tools or effort. Further, if the indicator aperture is drilled through an internal floor insert in the interior of the magazine and also through a slidably removable base plate at the bottom of the magazine, the indicator prevents accidental dismantling of the magazine because the base plate cannot be slidably removed while the indicator is projecting through the indicator aperture. Optionally, a retaining member can be provided at the end of the indicator and the user can pull on the retaining member to pull the follower downwardly and allow speed loading of the magazine. 
     Existing guns can be easily retrofitted merely by providing replacement magazines that are equipped with the indicator. Existing magazines can be easily retrofitted merely by forming an indicator aperture in the magazine (or by expanding the existing aperture already formed in some magazines), attaching one end of an indicator member to the follower, and allowing the other end of the indicator member to extend through the indicator aperture. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side cut away view of a preferred embodiment of the magazine of the present invention with three bullets in the magazine. 
     FIG. 2 is a front cut away view of the embodiment of FIG. 1 with five bullets in the magazine. 
     FIG. 3 is a side cut away view of another preferred embodiment of the indicator member. 
     FIG. 4 is a perspective view of still another preferred embodiment of an indicator member according to this invention in which a first plurality of knots has a second plurality of different configurations which provide a tactile code of how many bullets remain in the magazine. 
     FIG. 5 is a side elevational cut away view of a gun according to this invention having the indicator member of FIG. 4 extending from the indicator aperture indicating that there are several bullets remaining in the magazine. 
    
    
     DESCRIPTION OF A PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, a preferred embodiment of the magazine 10 of the present invention comprises a hollow body 12 configured to receive a plurality of bullets B. The hollow body 12 is provided with a bullet aperture 14 through which bullets are loaded into the hollow body 12. An internal floor insert 15 is provided near the bottom of the body 12 and is retained in the body 12 by a base plate 16, which is slidably removable from the bottom of the body 12. The internal floor insert 15 is provided with a first indicator aperture 15a, and the base plate is provided with a second indicator aperture 16a. A follower 20 is slidably mounted inside the hollow body 12 and is urged towards the bullet aperture 14, preferably by a coil spring 22 disposed between the follower 20 and the internal floor insert 15. An indicator member 30, preferably a strand provided with a series of knots 32, is attached to the bottom of the follower 24 (preferably by drilling a hole 24a through the follower and securing the indicator member 30 to the hole 24a) and projects through the indicator apertures 15a and 16a so that an indicator length 34 projects outwardly from the base plate 16. 
     Preferably, in the simplest embodiment, the number of knots 32 is equal to the number of bullets that the magazine can hold and the knots 32 are spaced at predetermined intervals so that when a number of bullets B is inserted into the magazine, an equal number of knots 32 projects outside the indicator apertures 15a and 16a. The intervals therefore would be determined by the pattern of displacement of the follower 20 as bullets B are removed from the body 12. It is also preferred that the series of knots 32 be displaced the appropriate distance from the bottom of the follower 24 so that the number of knots 32 extending outside the magazine 10 is equal to the number of bullets B remaining in the magazine 10. 
     For magazines in which the bullets are stacked directly on top of each other, the knots 32 would be spaced at intervals approximately equal to one bullet diameter because the pattern of displacement of the follower 20 as bullets B are removed from the body 12 would be a series of equidistant intervals, with each interval approximately equal to a bullet diameter. 
     For magazines in which the bullets B are not stacked directly on top of each other, but are laterally offset, as shown in FIG. 2 and as is done in high capacity magazines, the intervals in the pattern of displacement of the follower 20 would be less than the diameter of a bullet B. Further, for magazines in which the offset between vertically abutting bullets varies because the width of the magazine varies, as shown in FIG. 2, the intervals in the pattern of displacement of the follower 20 would not be equal, but would be spaced along the indicator member 30 at varying intervals determined by the displacement of the follower 20 caused by the ejection of each bullet B. For example, the ejection of the last bullet in the magazine 10 would cause the largest displacement of the follower 20 because part of the follower 20 can extend into the bullet aperture 14. However, the ejection of the second to last bullet would cause a smaller displacement because the presence of the last bullet would prevent the follower 20 from projecting into the bullet aperture 14 and because the second to last bullet is offset laterally from the last bullet, so that the displacement would be less than a single bullet diameter. Also, because the top of the magazine 10 is tapered towards the bullet aperture 14, the amount of lateral offset between vertically adjacent bullets will vary depending on the vertical position of the bullets in the magazine 10, which will cause the amount of displacement as bullets are ejected through the bullet aperture 14 to vary depending on the vertical position of the bullets as well. 
     The above description of the pattern of displacement of the follower 20 as bullets are removed from the body 12 is provided only as an example. Each type of magazine will have a different pattern of displacement of the follower as bullets are removed from the body. Although the necessary spacing of the knots 32 can be determined precisely using mathematical methods and analyses, it is simpler and preferable to determine the spacing empirically simply by attaching the indicator member 30 to the follower 20 and marking the positions for the knots 32 on the indicator length 34 as bullets are ejected from the magazine 10, thus marking the pattern of displacement of the follower 20 as bullets B are removed. The spacing between the knots 32 only needs to be approximate because the use needs only to count the number of knots 32 projecting outside the magazine 10, not to measure the spacing between the knots 32. 
     In a more elaborate embodiment, each knot could correspond to a predetermined number of bullets remaining in the magazine. For example, each knot could correspond to two, three or five bullets. This embodiment might be preferred if, for example, the user will be wearing gloves or otherwise have less ability to feel the number of knots if they are spaced closely together. 
     In an even more elaborate embodiment, there would be a first plurality of knots having a second plurality of configurations, and the configurations could be coded to indicate the number of knots remaining, so that the user would not have to count the knots, but could instead determine the number of bullets remaining merely by feeling the knot closest to the gun. For example, as shown in FIG. 4, the knots could be substantially round with a flattened side, and the orientation of the flattened side could vary depending on the number of bullets. Thus, the flattened side on the left could indicate a first number of bullets left, the flattened side facing forward could indicate a second number of bullets left, the flattened side facing to the right could indicate a third number of bullets left, and there could be individual round (unflattened) knots for each of the remaining bullets. For another example, the knots could have a polygonal cross section in a horizontal plane, with the number of sides on the polygon corresponding to a predetermined number of bullets remaining. Of course, the configuration of the knots could be varied by using a number of bumps on the knot, braille or some other tactile code on the knots as well. There are many ways in which the configurations of the knots can be varied to provide a tactile code of how many bullets remain in the magazine, but preferably the tactile code would require feeling only the knot closest to the magazine to determine how many bullets remain. However, the use of coded knots might not be preferred in certain situations, such as where the user will be wearing gloves so that the user would be impaired from tactilely reading the code. 
     Optionally, a removable grip 36 can be removably attached to the indicator length 34 so the user can pull the follower 20 to abut against the internal floor plate 15 so that bullets B can be loaded into the magazine 10 quickly because they can be loaded without having to overcome the bias of the coil spring 22. This is called &#34;speed loading.&#34; 
     The indicator member 30 is preferably sufficiently rigid to extend directly from the bottom of the follower 24 through the indicator apertures 15a and 16a. However, the indicator member 30 should be resilient enough that it will not present an impediment to use of the gun. As used herein, &#34;flexible&#34; shall mean sufficiently rigid yet sufficiently resilient, as indicated above. The indicator member 30 can be made from a single material, preferably plastic. 
     Referring to FIG. 3, shown is another preferred embodiment of an indicator according to this invention, with the magazine 10 cut away for clarity. This alternative embodiment comprises a strand 60, preferably of braided steel, that is attached to the follower (not shown), with indicator beads 64 spaced along its length at appropriate intervals by spacer beads 68. The indicator beads 64 and spacer beads 68 are retained on the strand by a lower retaining member 72 and an upper retaining member 74. The indicator beads 64 and spacer beads 68 can be made from various materials, such as plastics, metals, woods or ceramics, as can the retaining members 72 and 74. 
     Referring to FIG. 5, shown is a side elevational cut away view of a gun 102 according to the present invention. The gun 102 has a gun body 104 with a magazine aperture for a magazine 110. The magazine has a hollow body 112 with a bullet aperture 114 through which bullets B are loaded into the hollow body 112, and also has an indicator aperture 115. A follower 124 is slidably mounted in the hollow body 112, and an indicator member 130 having a plurality of knows 131, 132 is attached to the bottom of the follower 124 and extends through the indicator aperture 115. Because a number of bullets B remain in the magazine 110, a number of knots 131, 132 remain projecting outside the magazine 110 indicating that fact. The specific number and configuration of knots 131, 132 corresponding to a specific number of bullets B remaining is preferably determined by making each of certain knots 131 on a first part correspond to first predetermined numbers of bullets (such as three or fives) remaining, with each of the remaining knots 132 on a second part corresponding to second predetermined numbers of bullets (such as ones) remaining. 
     It is clear from the foregoing that it would be a very easy matter to retrofit existing magazines to practice this invention merely by attaching an indicator member to the follower and drilling a hole through the internal floor insert and base plate (if they are not already provided with a suitable aperture) to allow the indicator member to project out the bottom of the magazine. 
     It is also clear that existing guns can easily be provided with this indicator merely by providing replacement magazines equipped with the indicator because the indicator is self contained in the magazine and does not require any cooperating structure in the gun itself. 
     Of course, this invention can be employed in guns that do not have removable magazines but into which bullets are loaded directly, as long as there is a follower that urges the bullets into the firing chamber and an indicator aperture for the indicator member. 
     The invention has been described with respect to a particular preferred embodiment. It will be obvious to those skilled in the art that changes and modifications can be made to the embodiment described above without departing from the scope and spirit of the invention. Accordingly, no limitations are to be implied or inferred in the scope of the invention except as specifically set forth in the attached claims.