RAPID LOADING MAGAZINE WITH REUSABLE MAGNETIC LOADING STRIP

Abstract

An apparatus and system for loading a firearm magazine by loading all cartridges at once. According to embodiments of the present disclosure, a firearm magazine has a cartridge guide that can be locked such that the loading spring is locked in a compressed position. A loading strip that is preloaded with cartridges may be loaded into a magazine and slidably removed to load all cartridges at once. Upon loading the cartridges, the cartridge guide may be unlocked such that the spring may enable the cartridge guide to feed the cartridges into a chamber when engaged with a firearm.

Description

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application 61/797,730, filed Dec. 14, 2012, hereby incorporated by reference.

FIELD

The present disclosure relates to the field of firearms, in particular a novel cartridge magazine for improved speed in loading a firearm.

BACKGROUND

Many solutions exist in the prior art exist for minimizing the loading time for a firearm magazine. While many of these solutions promote a more durable magazine, reduce the dexterity required by the operator, or allow greater simplicity of loading cartridges, all prior art solutions still require the operator to load cartridge one at a time or require a bulky ammunition cartridge to remain in the magazine and reduce the reliability of the firearm and increase cartridge jamming. A standard rifle magazine holds 30 cartridges. Loading a 30 cartridge magazine, even with the enhancements provided by some of the prior art solutions, still requires approximately one second or more per bullet. Despite the enhancements provided by the prior art, it still takes an operator at least 30 seconds to load a standard 30 cartridge magazine.

Gaidos U.S. Pat. No. 1,797,951 discloses a firearm magazine with a flat sliding plate for closing a side of its magazine chamber. However, it includes a slidably mounted latch sensitive to dirt and debris adversely affecting its operation. Also, the plate has slots machined along its edges for slidingly engaging inwardly-deformed edges of the magazine member. The slots are expensive to machine, and further the slots form a narrow track that may trap dirt and debris adversely affecting slidability of the plate, especially when the magazine is being loaded in dirty environments. Gaidos, like Brown, also discloses an open slot along its length that potentially allows debris to enter the magazine, thus greatly reducing its resistance to intrusion of debris. Also, a pull ring protrudes from an end of the plate and, along with the latch, is subject to getting caught on objects when manipulating the magazine.

Kim U.S. Pat. No. 4,688,344 discloses a separate loading apparatus that contains the ammunition for insertion into the magazine. This design is overly complex and uses many extra parts that would be cumbersome to carry or use. The process needed to load a magazine with this design is also more tedious than the conventional one-by-one loading method.

Guy et al. Patent Application Publication No. 2005/0081421 A1 discloses a “Heavy Duty Magazine Loader” that again requires the loading of a shell loader prior to loading the magazine itself. This design requires a multitude of heavy parts for its construction. The design of this loader is bulky, overweight, and is far from portable. It also does not allow for the loading of a magazine where the ammunition is inserted on an angle, such as most semi-automatic handgun magazines.

Ball U.S. Pat. No. 2,862,324 discloses a “Clip Slide Depressor.” This is yet another separate item that has to be carried by the user. The user's hands could just as easily accomplish the function that this design performs. This concept arguably offers no real advantage to loading a magazine.

Herpel Patent Application Publication No. US 2005/0150148 A1 discloses a magazine having a cord attached to the follower for pulling the follower toward the base to relieve the spring tension that would otherwise oppose the force of inserting ammunition. This concept requires the use of a ring at the bottom of the cord that remains extended from the magazine housing when the magazine is filled with ammunition. The cord and ring could easily be caught on objects while the magazine is dispensing the ammunition into the firearm, hence jeopardizing the critical function of the magazine's dispensing action. The cord also has the possibility of becoming tangled with the inner workings of the magazine, hence jeopardizing the function of the magazine. This concept also allows for the possibility that a round of ammunition could be inserted in the correct direction, but tumble while falling to the bottom and landing in the wrong direction.

Phillips U.S. Pat. No. 6,807,764 B1 discloses an object similar to that of the Ball U.S. Pat. No. 2,862,324. This is yet another separate item that has to be carried by the user. The user's hands could just as easily accomplish the function that this design performs. This concept arguably offers no real advantage to loading a magazine.

Pikula U.S. Pat. No. 6,678,985 B2 discloses a magazine-loading tray. This concept has little, if any, advantage over conventional one-by-one loading. The tray must be loaded, then the magazine must be loaded using the tray, providing no clear advantage to the user. This design is also quite bulky and would not be very portable.

No solution exists that allows a firearm user to load an entire 20 to 30 cartridge magazine in one step, while also eliminating any cartridge casing or strapping from remaining inside the magazine thereby ensuring firearm reliability. What is needed, therefore, is an apparatus and system that enables a user to load an entire firearm magazine at once, and allows the user to user off-the-shelf cartridges without any additional strapping or casings.

SUMMARY

The following presents a simplified summary of some embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later.

An object of the present invention is an ammunition loading apparatus comprising a first surface, the first surface being substantially planar and shaped to correspond with a contour of a firearm magazine; a side wall disposed substantially along a perimeter of the first surface and terminating at a distal end of the first surface defining an opening and an interior portion, the side wall being contoured at a distal portion opposite the opening defining at least one cartridge contour; a magnetic portion disposed substantially along a length of the first surface defining at least one cartridge row within the interior portion; and, a handle coupled to a distal potion of the side wall and the first surface adjacent to the at least one cartridge contour.

Another object of the present invention is an apparatus for storing cartridges for a firearm, with each cartridge including a hollow shell carrying a bullet at a first end thereof and having a circular bottom at an opposite second end thereof, comprising an elongated housing configured to selectively engage with a firearm, the housing having side walls and a base defining sides, a bottom and an opening disposed substantially along a side portion, and the housing having a channel disposed substantially the length of the housing and configured to be slidably coupled with an ammunition loading strip, the ammunition loading strip having a first surface, a side wall disposed substantially along a perimeter of the first surface and terminating at a distal end of the first surface defining an opening and an interior portion, the side wall being contoured at a distal portion opposite the opening defining a first cartridge contour, and a magnetic portion disposed substantially along a length of the first surface defining a cartridge row within the interior portion; a cartridge guide, the cartridge guide being slidably coupled with an interior portion of the housing, and the cartridge guide having a handle coupled to a cartridge rest; and, a cartridge guide lever having a protrusion selectively engaged with an aperture of the cartridge guide, and disposed on a lower portion of the housing.

Yet another object of the present invention is a firearm magazine system comprising a housing configured to selectively engage with a firearm, the housing having side walls and a base defining sides, a bottom and an opening disposed substantially along a side portion, and the housing having a channel disposed substantially the length of the housing and configured to be slidably engaged with an ammunition loading strip; a cartridge guide, the bullet guide being slidably coupled with an interior portion of the housing, and the cartridge guide having a handle coupled to a cartridge rest; a cartridge guide lever having a protrusion selectively engaged with an aperture of the cartridge guide, and disposed on a lower portion of the housing; and an ammunition loading strip, the ammunition loading strip comprising a first surface, the first surface being substantially planar and shaped to correspond with a contour of a firearm magazine; a side wall disposed substantially along a perimeter of the first surface and terminating at a distal end of the first surface defining an opening and an interior portion, the side wall being contoured at a distal portion opposite the opening defining a first cartridge contour and a second cartridge contour; and, a handle coupled to a distal portion of the side wall and the first surface adjacent to the first cartridge contour and the second cartridge contour.

The foregoing has outlined rather broadly the more pertinent and important features of the present invention so that the detailed description of the invention that follows may be better understood and so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the disclosed specific methods and structures may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should be realized by those skilled in the art that such equivalent structures do not depart from the spirit and scope of the invention as set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is an isometric view of a firearm magazine housing in accordance with an embodiment;

FIG. 2 is an isometric view of a bullet cover of a firearm magazine housing in accordance with an embodiment;

FIG. 3 is an isometric view of a bullet cover of a firearm magazine housing in accordance with an embodiment;

FIG. 4 is an isometric view of a bullet guide of a firearm magazine in accordance with an embodiment;

FIG. 5 is a cross sectional view of a firearm magazine housing in accordance with an embodiment;

FIG. 6 is a cross sectional view of a firearm magazine housing in accordance with an embodiment;

FIG. 7 is a cross sectional view of a firearm magazine housing in accordance with an embodiment;

FIG. 8 is an isometric view of an ammunition loading strip in accordance with an embodiment; and,

FIG. 9 is an isometric view of an ammunition loading strip and a bullet container in accordance with an embodiment.

DETAILED DESCRIPTION

Exemplary embodiments are described herein to provide a detailed description of the present disclosure. Variations of these embodiments will be apparent to those of skill in the art. Moreover, certain terminology is used in the following description for convenience only and is not limiting. For example, the words “right,” “left,” “top,” “bottom,” “upper,” “lower,” “inner” and “outer” designate directions in the drawings to which reference is made. The word “a” is defined to mean “at least one.” The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import.

The present disclosure provides for an apparatus and system for a rapid loading firearm magazine that can be loaded to full capacity without loading cartridges one at a time. A cartridge (also called a round or a shell) is a type of ammunition packaging a bullet, a propellant substance (usually either smokeless powder or black powder) and a primer within a metallic, paper, or plastic case that is precisely made to fit within the firing chamber of a firearm. According to an embodiment, a loading strip with a magnetic interface is configured to engage with a channel in a magazine. A magazine may be defined as an ammunition storage and feeding device within or attached to a repeating firearm. Magazines can be removable (detachable) or integral to the firearm. The magazine functions by moving the cartridges stored in the magazine into a position where they may be loaded into the chamber by the action of the firearm. The magazine often has a spring engaged with a cartridge guide to push each cartridge up to the chamber. As a cartridge is fired and the shell is evacuated from the chamber, the spring and cartridge guide ensure the next cartridge in the magazine is fed into the chamber. The magazine has an interior portion where the ammunition is stored and an upper portion where the ammunition is generally loaded into the magazine when disengaged from a firearm, and loaded into the chamber when engaged with a firearm. The loading strip should have the same curvature of the magazine so it can be fed substantially the entire length of the interior of the magazine. According to an embodiment, a firearm user can preload cartridges onto a surface of the loading strip containing a magnetized portion. The magnetized portion should provide enough attractive force to hold the cartridge in place on the loading strip, while also allowing the cartridge to be readily removed from the strip. In an embodiment, the loading strip may be configured to accept two rows of cartridges such that the cartridges are in the proper configuration when placed in the magazine to load correctly in the firearm chamber without jamming. Jamming occurs when the cartridge does not load properly into the chamber and the cartridge becomes jammed. The loading strip may be loaded by the user or may come loaded from the factory for faster loading, especially in a military setting.

According to an embodiment, a user loads a preloaded loading strip into a magazine. The magazine may have a slidable side portion that enables the cartridge guide to be lowered to a locked position, such that the spring cannot exert force on the cartridges to move them upward in the magazine. When the cartridge guide is engaged in the locked position, the user may feed the loading strip into the magazine. Once the cartridges are loaded, the loading strip may be removed by placing the user's hand over the opening of the magazine, such that no cartridges may be removed, and pulling upwards on the strip. The magnetic portion of the loading strip will become disengaged from the cartridges, and the loading strip will easily slide out of the cartridge leaving the cartridges behind in the magazine in the desired configuration. Once the cartridges are loaded into the magazine, and the loading strip is removed, the cartridge guide may reengaged and the spring will exert pressure on the loaded cartridges to move them upward in the magazine, and into the chamber when the magazine is engaged with a firearm.

FIG. 1 is an isometric view of a firearm magazine housing in accordance with an embodiment. In an embodiment, magazine 100 is configured to engage with the chamber of a firearm, for example an AR-15. Magazine 100 has an upper opening 102 to facilitate loading of cartridges into the magazine body 106, and the feeding of cartridges into the chamber of a firearm. Magazine 100 may have an open side portion to enable the user to see the cartridges as they are loaded into the magazine. A sliding magazine cap may be used to selectively cover the open side portion. Upper opening 102 has a substantially rectangular opening at one end to accommodate a loading strip with attached cartridges. The rectangular opening can be substituted for any geometric configuration to correspond with the shape of a loading strip. Upper opening 102 is engaged with the chamber of a firearm when in use. Magazine 100 has a channel 104 configured to guide a loading strip into magazine body 106. In an embodiment, channel 104 is comprised of a shallow rectangular groove, but this configuration can be readily substituted for other configurations to correspond with the shape of a cartridge loading strip, such as semi-circular or a keyed slot. Channel 104 runs substantially the entire length of magazine 100 to enable a loading strip to be fed to the bottom of magazine body 106.

Still referring to FIG. 1, a groove 108 may be disposed along an exterior portion of magazine body 106 such that a side face or cap (as shown in FIGS. 2 and 3) may be slidably connected to magazine 100 to enable a user to have selective access to the interior portion of magazine body 106. Groove 108 may run on opposing sides of magazine body 106, as illustrated in FIG. 1, and may be formed by the definition of a gap between an exterior surface of magazine body 106 and magazine casing 110. Magazine casing 110 may provide an additional exterior surface to magazine body 106, and may be integral to magazine body 106 or a removable shell to magazine body 106. Magazine 100 may also have a cartridge guide lever 112 to enable selective engagement of a cartridge guide in an interior portion of magazine body 106 between a locked position and an unlocked position. Cartridge guide lever 112 may be depressed to free a cartridge guide from a locked position.

FIGS. 2 and 3 show an isometric view of a cartridge cover of a firearm magazine housing in accordance with an embodiment. Cartridge cover 200 may interface with groove 108 in FIG. 1 to enclose an open side portion of magazine 100, as shown in FIG. 1. Cartridge cover 200 may have an upper portion 202 to enable selective coupling with magazine 100, as well as an opening 204 to enable a user to see how many cartridges, or rounds of ammunition, are housed in magazine body 106. Opening 204 should be wide enough to accommodate a handle from a cartridge guide housed in magazine body 106. Cartridge notations 206 may be included on a surface of cartridge cover 200 to correspond with the number of cartridges housed in magazine body 206. FIG. 3 shows a rear surface 302 of cartridge cover 200 that interfaces with groove 108 in FIG. 1 to enclose an open side portion of magazine 100.

FIG. 4 is an isometric view of a cartridge guide of a firearm magazine in accordance with an embodiment. According to an embodiment, a cartridge guide 402 has a cartridge rest 404 defined by an inclined upper portion. Cartridge rest 404 is configured to position cartridges housed in magazine 100, as shown in FIG. 1, in an inclined position such that the tip of the cartridge is at least one degree to 20 degrees higher than the base to facilitate loading of the cartridge into the chamber of a firearm. Cartridge guide 402 may have a handle 408 to enable a user to pull down on cartridge guide 402 to engage it in a locked position. Cartridge guide 402 may be locked by interfacing guide aperture 406 with a locking mechanism. Guide aperture 406 may be defined as longitudinal facing surface with a slot or opening configured to selectively engage with a locking mechanism, such as that shown in FIG. 5.

FIG. 5 is a cross sectional view of a firearm magazine housing in accordance with an embodiment. According to an embodiment, cartridge guide lever 112 has a protrusion or locking mechanism 502 that extends into magazine body 106. A spring 504 exerts lateral pressure on cartridge guide lever 112 such that lever 112 can be depressed to retract locking mechanism 502 in a lateral motion toward the side of magazine body 106. Spring 504 exerts lateral pressure on cartridge guide lever 112 such that locking mechanism 502 remains within magazine body 106. Referring now to FIG. 6, cartridge guide 402 is housed within magazine body 106. A spring 602 exerts upward pressure on cartridge guide 402 such that cartridges are continuously fed upward to a firearm chamber when the magazine is engaged with a firearm. Spring 602 can be compressed by pulling downward on handle 408. As shown in FIG. 7, guide aperture 406 can interface with locking mechanism 502 in order to lock cartridge guide 402 and keep spring 602 depressed. This allows a user to load an ammunition loading strip (as shown in FIGS. 7 and 8) into magazine body 106 without interference from cartridge guide 402. Once cartridges have been loaded, cartridge guide 402 can be unlocked by depressing cartridge guide lever 112 and disengaging locking mechanism 502 from guide aperture 406. Spring 602 is now free to exert upward force on the loaded cartridges to accommodate loading into a firearm chamber.

FIG. 8 is an isometric view of an ammunition loading strip in accordance with an embodiment. According to an embodiment, loading strip 800 is an elongated apparatus having a handle 802, a cartridge surface 806, and a magnetic surface 810. Handle 802 allows a user to more easily grip loading strip 800 and may include cut-outs 804 to improve grip. Cartridge surface 806 may be substantially planar and shaped to correspond with a magazine. Magnetic surface 810 may be disposed substantially the length of cartridge surface 806. Magnetic surface 810 enables a steel cartridge to be coupled to cartridge surface 806 through attractive magnetic forces. The magnetic force should be strong enough to hold the cartridge 812 to cartridge surface 806 when a loaded cartridge 812 is held perpendicular to vertical when engaged with magnetic surface 810. Side walls 808 are used to organize a row or rows of attached cartridges to facilitate organized loading into a magazine. In a preferred embodiment, the loading strip is organized into two rows. Side walls 808 may form a contour or contours to define the beginning of at least one row of cartridges. In some embodiments, the entire loading strip may be made of a magnetized material thereby eliminating magnetic surface 810 as a separate element. It is also anticipated that cartridge surface 806 may be made from a magnetized material, also eliminating magnetic surface 810 as a separate element.

Still referring to FIG. 8, according to an exemplary method of use, a user may engage cartridges 812 with magnetic surface 810 by placing the base of cartridges 812 on magnetic surface 810. The user can line up cartridges 812 on cartridge surface 806 according to rows defined by the contours in side walls 808. In an exemplary embodiment, loading strip 800 holds two rows of 15 cartridges 812. Once the cartridges are loaded on cartridge surface 806, the user can feed loading strip 800 into a firearm magazine, as exemplified by magazine 100 in FIG. 1. Once loaded into the magazine, the user should place their hand over the upper opening of the magazine, as illustrated by upper opening 102 of magazine 100 in FIG. 1, and pull firmly on handle 802. This will remove loading strip 802 from the interior portion of the magazine, but will leave cartridges 812 inside the magazine. This enables a user to load an entire 30 round magazine in one step without leaving any cartridge strapping or packaging inside the magazine. This is very desirable when the user wants to reduce the reload time for a firearm. In an embodiment, a magazine loading spring is compressed and the cartridge guide is locked as described in FIGS. 5-7 to facilitate loading of loading strip 800 without interference from internal mechanisms in the magazine.

FIG. 9 is an isometric view of an ammunition loading strip and a cartridge container in accordance with an embodiment. In some embodiments, cartridges 812 (as shown in FIG. 8) may be preloaded on loading strip 800 and housed in a box or packaging 900 until ready for use. This may be how ammunition is loaded from the factory or manufacturer, and enables the user to rapidly open ammunition box 900, remove preloaded loading strip 800, insert preloaded loading strip 800 into the magazine, remove the loading strip, and engage the magazine to the firearm. This would greatly reduce the time required to load a magazine, especially in a military setting.

The present disclosure includes that contained in the appended claims as well as that of the foregoing description. Although this invention has been described in its exemplary forms with a certain degree of particularity, it is understood that the present disclosure of has been made only by way of example and numerous changes in the details of construction and combination and arrangement of parts may be employed without departing from the spirit and scope of the invention.

Claims

1. A cartridge loading apparatus, with each cartridge including a hollow shell carrying a bullet at a first end thereof and having a circular bottom at an opposite second end thereof, comprising:

a first surface, the first surface being substantially planar and shaped to correspond with a contour of a firearm magazine;

a side wall disposed substantially along a perimeter of the first surface and terminating at a distal end of the first surface defining an opening and an interior portion, the side wall being contoured at a distal portion opposite the opening defining at least one cartridge contour;

a magnetic portion disposed substantially along a length of the first surface defining at least one cartridge row within the interior portion; and,

a handle coupled to a distal portion of the side wall and the first surface adjacent to the at least one cartridge contour.

2. The ammunition loading apparatus of claim 1 wherein the magnetic portion comprises substantially the area of the first surface.

3. The ammunition loading apparatus of claim 1 wherein the apparatus is made from a material selected from the group consisting of high density plastic, steel and aluminum.

4. The ammunition loading apparatus of claim 1 wherein the at least one cartridge contour defines rows for a first row of cartridges and a second row of cartridges.

5. The ammunition loading apparatus of claim 1 further comprising a first row of cartridges and a second row of cartridges.

6. The ammunition loading apparatus of claim 5 wherein the first row of cartridges and the second row of cartridges are removably engaged with the magnetic portion.

7. An apparatus for storing cartridges for a firearm, with each cartridge including a hollow shell carrying a bullet at a first end thereof and having a circular bottom at an opposite second end thereof, comprising:

an elongated housing configured to selectively engage with a firearm, the housing having side walls and a base defining sides, a bottom and an opening disposed substantially along a side portion, and the housing having a channel disposed substantially the length of the housing and configured to be slidably coupled with an ammunition loading strip, the ammunition loading strip having a first surface, a side wall disposed substantially along a perimeter of the first surface and terminating at a distal end of the first surface defining an opening and an interior portion, the side wall being contoured at a distal portion opposite the opening defining a first cartridge contour, and a magnetic portion disposed substantially along a length of the first surface defining a cartridge row within the interior portion;

a cartridge guide, the cartridge guide being slidably coupled with an interior portion of the housing, and the cartridge guide having a handle coupled to a cartridge rest; and,

a cartridge guide lever having a protrusion selectively engaged with an aperture of the cartridge guide, and disposed on a lower portion of the housing.

8. The firearm magazine of claim 7 wherein the cartridge guide is configurable between a first engaged position and a second locked position.

9. The firearm magazine of claim 7 wherein the cartridge guide further comprises an inclined portion configured to feed a cartridge into a firearm chamber according to a predetermined angle.

10. The firearm magazine of claim 7 further comprising a spring operably engaged with the cartridge guide lever.

11. The firearm magazine of claim 7 further comprising cartridge number notations on an exterior surface of the housing.

12. The firearm magazine of claim 7 further comprising a cartridge cover coupled to the cartridge guide and slidably engaged with the housing.

13. The firearm magazine of claim 8 wherein the locked position corresponds to engagement of the aperture of the cartridge guide and the protrusion of the cartridge guide lever.

14. A firearm magazine system comprising:

a housing configured to selectively engage with a firearm, the housing having side walls and a base defining sides, a bottom and an opening disposed substantially along a side portion, and the housing having a channel disposed substantially the length of the housing and configured to be slidably engaged with an ammunition loading strip;

a cartridge guide, the bullet guide being slidably coupled with an interior portion of the housing, and the cartridge guide having a handle coupled to a cartridge rest;

a cartridge guide lever having a protrusion selectively engaged with an aperture of the cartridge guide, and disposed on a lower portion of the housing; and,

an ammunition loading strip, the ammunition loading strip comprising:

a first surface, the first surface being substantially planar and shaped to correspond with a contour of a firearm magazine;

a side wall disposed substantially along a perimeter of the first surface and terminating at a distal end of the first surface defining an opening and an interior portion, the side wall being contoured at a distal portion opposite the opening defining a first cartridge contour and a second cartridge contour; and,

a handle coupled to a distal portion of the side wall and the first surface adjacent to the first cartridge contour and the second cartridge contour.

15. The firearm magazine assembly of claim 14 wherein the first cartridge contour and the second cartridge contour define rows for a first row of cartridges and a second row of cartridges.

16. The firearm magazine assembly of claim 14 wherein the magnetic portion comprises substantially the area of the first surface.

17. The firearm magazine assembly of claim 14 wherein the cartridge guide further comprises an inclined portion configured to feed a cartridge into a firearm chamber according to a predetermined angle.

18. The firearm magazine assembly of claim 14 further comprising a cartridge cover coupled to the cartridge guide and slidably engaged with the housing.

19. The firearm magazine assembly of claim 14 further comprising a spring operably engaged with the cartridge guide lever.

20. The firearm magazine assembly of claim 14 further comprising cartridge number notations on an exterior surface of the housing.