DUAL SIDED CONTAINER

Abstract

A container has openings at each end and has two compartments for holding two complementary materials. The container stands on either end and can dispense one of the two materials from each end. In one embodiment the container is separable into two individual containers. The individual containers are attached together using various means such as shrink wrap material, perforated strips, interlocking sections and the like.

Description

BACKGROUND OF THE INVENTION

The present invention relates primarily to containers. More specifically, the present invention relates to an apparatus for holding two types of materials in a convenient, portable, cost effective, attractive and space saving manner.

For thousands of years mankind has continually developed better ways to carry and store materials of many types. Technology has advanced from animal skins and clay urns to modern day molded plastic containers. The variety of materials requiring containers is nearly limitless and ranges from materials such as liquids, solids, foods, and drinks to medicines, detergents, makeup, chemicals, adhesives, poisons and the like. More recently, the advance of technology and the rise in the number and variety of consumer and industrial goods has produced an explosion in the need for improved containers that have better functionality and mass appeal to consumers. Consumers place a high priority on packaging that is new, innovative, visually appealing, and convenient. They are eager for products that save time and simplify their hurried lives. Further, many consumers are attracted to anything new and different. As such, many types of containers and packaging have been introduced into the marketplace and the prior art shows many examples of containers and packages of countless shapes, sizes and features.

Businesses are interested in new and innovative containers. Businesses want to attract and satisfy customers, reduce storage space and reduce shipping costs. Customers want new and useful products and therefore businesses can attract and satisfy these customers by providing new and useful products/containers. Packaging may also influence a consumer's opinion about the quality of the product inside the container. An attractive container may raise a consumer's opinion of a product. Conversely, an old or unattractive container may lower a consumer's opinion of a product. Further, since space is at a premium at most businesses, a container that saves space is desirable. This is an advantage on store shelves where space is at a premium and also in warehouses. Finally, business is concerned with profit. Therefore a product that is less expensive to manufacture and ship is desirable. Business is always interested in improved containers.

Industry is likewise interested in new and useful containers. Industry desires containers/products that improve worker productivity, save time, reduce waste, and improve safety. The driving force of industry is profit. A container/package that improves workers' productivity improves profit. A container/package can do this by having an improved design that allows a worker to easily and quickly accomplish a task in a minimum amount of time. A worker that must spend time looking for multiple containers, studying the directions on each container, verifying proper mixture ratios, etc. can waste valuable time and money. Further, if multiple ingredients are required for a task, one lost or misplaced container can delay or cancel a task. Finally, if incorrect ingredients are used/mixed together, a poor quality product or job may result.

Similarly, industry is interested in reducing waste. When multiple containers of multiple ingredients must be purchased, the chance of purchasing the optimal quantity of each ingredient is remote. The unused portion of the surplus ingredient frequently degrades and has to be discarded. This creates waste.

Safety is also a concern with business and some containers can create an unnecessary safety risk. For example, where chemicals must be mixed, an inadvertent error in mixing ingredients by an employee could cause noxious fumes, toxic gas, or even violent explosions. It is clear that industry is interested in new and useful containers that provide solutions to these concerns.

Accordingly, a need exists for a new container to hold the many consumer and industrial materials that would benefit from an improved container. A new container is needed that provides visual appeal, more convenience, and more value for the consumer. Similarly there is a need for a new container that would simplify usage, save time, improve safety, reduce waste, reduce shipping costs and save space. Therefore, a container that provides the aforementioned advantages for consumers, business and industry is desired.

SUMMARY OF THE PRESENT INVENTION

The aforementioned drawbacks and disadvantages of the prior art containers have been identified and a solution is set forth herein by an inventive dual sided container and method which comprises a container having two compartments and openings at opposing ends. The dual sided container is useful in holding a wide variety of materials ranging from foods and beverages to medicines and chemicals. The container is useful for holding both consumer and industrial materials. In a preferred embodiment, the container has a support surface on each of the opposing ends such that the contain can sit on either end. One embodiment includes an internal divider for providing a barrier between the two materials in the container. The container may have two compartments of equal volume or of unequal volumes. In some preferred embodiments the container is separable into two compartments. One of these embodiments includes wrapping material that is applied to the exterior of both compartments and secures the two compartments together while also allowing a user to separate the two compartments if desired. In another embodiment, the container includes at least one perforation or scoring near the junction of the two compartments. This allows a user to easily separate the two compartments. In yet another embodiment, a removable belt secures the two compartments together. Another embodiment provides a twist-lock mechanism such that the two compartments may be separated and then re-connected. The inventive container is particularly useful in holding complementary materials such as mustard and ketchup. The two complementary materials thus remain close together and the container takes less space than two separate containers.

One feature of the present invention are the two compartments. Having two compartments in a single container provides the advantage of packaging complementary materials such as ketchup and mustard or epoxy and resin into a single container. This makes both materials available when needed. One material is not lost or misplaced. In addition, optimal quantities of each material can be packaged together, thus simplifying some mixing tasks and also reducing waste.

Another feature of the present invention are openings at opposing ends of the container. These openings make both materials readily available. For example, a consumer may pour ketchup from one opening of the container, and then simply flip the container over and pour mustard from the opposing opening. A related feature are the caps that cover the two openings. The caps are designed to support the container when it is set on a surface. The caps are sufficiently large and flat to provide a stable support for the container. A user simply sets the container on the end of the container that is not currently in use. The container can be quickly set on either end that is not currently in use.

Yet another feature of the present invention are the detachable compartments. Briefly, this feature allows the container to be separated into two independent containers. While packaging two complementary materials together often makes sense, it is also useful for a user to be able to separate the products. For example, packaging tartar sauce and cocktail sauce together may be useful. However, a user may also want to separate these products after they are purchased.

A related feature of one embodiment of the present invention is a wrapper or label that is applied to the exterior of the container and secures the two compartments together. For example, a plastic shrink wrap material may be easily applied to the container. The wrapper may then be weakened with perforations, scoring or the like so that the two compartments are readily separated if desired.

Another related feature of one embodiment of the invention is a removable belt that secures the two compartments together. The belt is similar to the removable perforated plastic tamper proof belts used on various products (e.g. plastic milk jug caps). The removable belt securely holds the two compartments together, yet allows a user to easily separate the two compartments. One embodiment also includes a pull tab to facilitate removal of the belt. In a related feature of one embodiment, the two compartments are attached with a twist-lock mechanism in which male and female portions of the two compartments interlock. This embodiment has the advantage of permitting the two compartments to be re-attached if desired.

To address the goals stated above, the inventive dual sided container provides a simple and elegant solution to some of the disadvantages of prior art containers. By combining the features of openings at opposing ends, two compartments, supporting caps, variable size compartments and detachability, the invention creates a new and interesting container for use by consumers, business, and industry. By solving the many deficiencies of the prior art, the invention provides a cost effective way to implement a new and improved container that can be used around the world. The invention is applicable to virtually any combination of materials/products whether in a home, at work, in business, for recreation, or elsewhere.

The present invention also includes a method of holding two complementary materials in a container that can dispense one of the materials from one end and the other material from the other end. The method also describes multiple embodiments of the container that are separable into two compartments and other features of the invention.

The invention comprises a container having a first compartment and a second compartment. Each compartment having an opening and each of the two compartments secured together. The compartments may be unequal in volume and may be detachable by a user. The openings are at opposing ends of the container. The invention further comprises caps that are sufficiently large and shaped to form a supporting surface for the dual sided container. The container may be set on either end.

The invention further comprises a means for attaching the two compartments together comprising a wrapper, a removable belt, perforated or scored portions of the container or interlocking parts.

The invention is useful in numerous environments including restaurants, airlines, hotels, travel, camping, and tailgating. Other environments include daycare centers, picnics, military deployment packages, construction sites, laboratories, businesses, schools, dormitories, and locker rooms.

A method of using the container comprisings the steps of: obtaining a container having two compartments and openings at opposing ends; obtaining two complementary materials and placing each material into one of the two compartments; obtaining two caps and securing the caps to the openings; and securing the two compartments together by various means. The method also envisions compartments of varying sizes so that different proportions of materials may be packaged together.

Other objects, advantages, and features of the invention will become apparent upon consideration of the following detailed description, when taken in conjunction with the accompanying drawings. The above brief description sets forth rather broadly the more important features of the present disclosure so that the detailed description that follows may be better understood, and so that the present contributions to the art may be better appreciated. There are, of course, additional features of the disclosures that will be described hereinafter which will form the subject matter of the claims.

In this respect, before explaining the preferred embodiment of the disclosure in detail, it is to be understood that the disclosure is not limited in its application to the details of the construction and the arrangement set forth in the following description or illustrated in the drawings. The dual sided container and method of the present disclosure is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for description and not limitation.

As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be used as a basis for designing other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims are regarded as including such equivalent constructions as far as they do not depart from the spirit and scope of the present invention.

Further, the purpose of the Abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers, and practitioners in the art who are not familiar with the patent or legal terms of phraseology, to learn quickly, from a cursory inspection, the nature of the technical disclosure of the application. Accordingly, the Abstract is intended to define neither the invention nor the application, which is only measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.

These and other objects, along with the various features, methods, and structures that characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the present disclosure, its advantages, and the specific objects attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention.

As such, while embodiments of the dual sided container are herein illustrated and described, it is to be appreciated that various changes, rearrangements and modifications may be made therein, without departing from the scope of the invention as defined by the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

As a compliment to the description and for better understanding of the specification presented herein, four pages of drawings are disclosed with an informative, but not limiting, intention.

FIG. 1A illustrates a front view of a dual sided container of one embodiment of the present invention with a shrink wrap label;

FIG. 1B is a side view of the dual sided container in FIG. 1A;

FIG. 1C is a top view of the dual sided container in FIG. 1A;

FIG. 2 illustrates a dual sided container of one embodiment of the present invention with a removable belt and pull tab;

FIG. 3 illustrates a dual sided container of one embodiment of the present invention with an internal divider and compartments of unequal volume;

FIG. 4 illustrates a dual sided container of the one embodiment of the present invention with interlocking parts;

FIG. 5A illustrates an alternate embodiment of a cap and one end of a dual sided container of the present invention; and,

FIG. 5B illustrates another alternate embodiment of a cap and one end of a dual sided container of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The best mode for carrying out the invention is presented in terms of the preferred embodiment. Similar referenced characters designate corresponding features throughout the several figures of the drawings.

For purposes of description herein, the terms “left”, “right”, “top” and “bottom” shall relate to the invention as oriented in FIG. 1A. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and methods illustrated in the attached drawings and described in the following specification are exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, these same referenced numerals will be used throughout the drawings to refer to the same or like parts. Like features between the various embodiments utilize similar numerical designations. Where appropriate, the various similar features have been further differentiated by an alphanumeric designation, wherein the corresponding alphabetic designator has been changed. Further, the dimensions illustrated in the drawings (if provided) are included for purposes of example only and are not intended to limit the scope of the present invention.

Hencefore, one preferred embodiment will be described. However, this is merely for description and it is understood that the size, shape, construction material, indicia, color and the like of container 10 and the various components are subject to change or variation consistent with the spirit of the invention.

An exemplary embodiment of the invention is shown in FIGS. 1A, 1B and 1C. The components of the invention will first be briefly described and then described in detail. Referring to FIG. 1A, the dual sided container 10 is viewed from the front. Container 10 includes first compartment 11A, second compartment 11B, first cap 12 and second cap 13. Wrapper 14 is attached to the exterior of first compartment 11A and second compartment 11B. Wrapper 14 includes perforations 14A, first indicia 14B and second indicia 14C. First cap 12 includes first lid 12A and second cap 13 includes second lid 13A. Body 15 includes both the first compartment 11A and second compartment 11B but does not include first cap 12 and second cap 13. Body 15 has first end 15A and a second end 15B.

Dual sided container 10 in one embodiment is constructed of conventional plastic material that is used to manufacture containers for products such as ketchup or mustard. This embodiment includes two compartments for holding two materials. First compartment 11A includes a first opening 11C by which material is placed into first compartment 11A and through which material is dispensed from first compartment 11A. Similarly, a second compartment 11B includes a second opening 11D by which a second material is placed into second compartment 11B and through which the second material is dispensed from second compartment 11B.

First cap 12 and second cap 13 are preferably made of plastic and cover first opening 11C and second opening 11D respectively. Caps 12 and 13 may screw on or snap onto first compartment 11A and second compartment 11B. Caps 12 and 13 include first lid 12A and second lid 13A that seal first opening 11C and second opening 11D. Caps 12 and 13 also preferably include a support surface 12B and 13B which is suitable for supporting the container 11 when it is set on a surface. Lids 12A and 13A may form a part of the supporting surface 12B and 13B when the lids 12A and 13A are closed.

Also shown in FIG. 1A is wrapper 14. Wrapper 14 serves dual purposes of providing labeling and also securing first and second compartments 11A and 11B together. While wrapper 14 may be made of many materials, the preferred embodiment uses plastic shrink wrap material. Wrapper 14 is preferably weakened along the junction of first compartment 11A and second compartment 11B by perforations/scoring 14A or the like. First indicia 14B and second indicia 14C are used to identify the product and communicate information to a user. While one preferred embodiment of container 10 is wide in the middle with tapered portions towards the top and bottom, the invention is not meant to be so limited. Those skilled in the art will understand that the invention may be adapted to many other shapes and sizes.

One of the features of the invention is having two complementary materials in one container. For this application we define complementary materials as materials that have some connection such that there is a some reason a user or manufacturer would consider it useful to package the materials together. Some examples of complementary materials include: creamer and sugar; salt and pepper; hot BBQ sauce and mild BBQ sauce; baby food carrots and applesauce; oil and vinegar; shampoo and conditioner; baby lotion and powder; pre-rinse mouthwash and mouthwash; dog shampoo and flea powder; eye makeup remover and makeup remover; car wash and rim cleaner; window cleaner and Rainx®; Tylenol® PM and regular Tylenol®; salad seasoning and bacon bits; tequila and lime juice; runners GOO and water; rubbing compound and wax; any two-part cleaners; any beverage and recommended mix; any pharmaceutical combination; any epoxy combination, any useful chemical combination; and doe urine and dominant buck. This is not an exhaustive list of materials, but is merely intended to illustrate the wide variety of complementary materials that would be useful to be packaged in the dual sided container of the present invention.

Referring now to FIGS. 1B and 1C, there are illustrated the side view of container 10 and top view of container 10 respectively. While many shapes are envisioned for the invention, this embodiment has the advantages of reducing space and all of the associated advantages related to space savings. FIG. 1B shows first compartment 11A, second compartment 11B, first cap 12, second cap 13, first supporting surface 12B, second supporting surface 13B, wrapper 14 and perforation/scoring 14A. FIG. 1C shows a top view of the container 10 (with lid 12A in an open position) and shows first cap 12 and first compartment 11A. Details of first cap 12 include supporting surface 12B, cap aperture 12C, lid 12A, lid nub 12D and flexible joint 12E. FIG. 1C is shown with lid 12A in the open position. Nub 12D plugs aperture 12C when lid 12A is closed.

Referring now to FIG. 2, there is illustrated an embodiment of the invention with a removable belt 16. Removable belt 16 secures first compartment 11A together with second compartment 11B. The concept of removable belts have been used in the prior art for such items as tamper proof bottles and the like. One example are removable belts used to secure caps to milk containers. The present invention uses removable belt 16 in a new way to secure two compartments together. Removable belt 16 preferably includes belt perforations 16B to facilitate removal of belt 16. Belt 16 may also include a pull tab 16A to aide in removing belt 16. FIG. 3 also illustrates a feature of the invention where compartments of materials are of unequal size. In FIG. 2, first compartment 11A is larger than second compartment 11B. This feature is advantageous in applications where unequal quantities of materials are applicable.

Referring now to FIG. 3, there is illustrated an embodiment of the dual sided container 10 that is not separable. In this embodiment first compartment 11A and second compartment 11B are permanently attached. Internal divider 31 separates the contents of first compartment 11A and second compartment 11B. First complementary material 30A is shown in first compartment 11A and second complementary material 30B is shown in second compartment 11B. Again, the compartments are of unequal size. In this embodiment, first material 30A could be salt and the second material 30B could be pepper. Since salt is typically used in higher quantities than pepper, it is advantageous to package them in unequal quantities.

Referring now to FIG. 4, there is illustrated an embodiment of the invention with twist-lock connections that permit compartments 11A and 11B to be detached and also to be reattached. Shown in FIG. 4 is first compartment 11A with interlocking aperture 40B and interlocking appendage 41A. Also shown is second compartment 11B with interlocking aperture 40A and interlocking appendage 41B. Interlocking apertures 40A, 40B are also referred to as female connectors 40A, 40B. Similarly, interlocking appendages 41A, 41B are also referred to as male connectors 41A, 41B. Interlocking appendage 41B couples with interlocking aperture 40B. Interlocking appendage 41A couples with interlocking aperture 40A. This embodiment permit's the first compartment 11A to be detached and reattached to second compartment 11B. Various designs and shapes of interlocking apertures and appendages are envisioned.

Referring now to FIG. 5A, there is illustrated an alternate embodiment of the top of container 50. In this embodiment body 51 does not taper near the top and cap 52 is larger. Cap 52 may attach to body 51 by means of snapping onto body 51 or by the use of threads (not shown). Cap 52 includes lid 52A and opening 52C and plug 52B. In this embodiment cap 52 and body 51 both provide a supporting surface on which container 50 can sit. An advantage of this embodiment is a larger and more stable supporting surface.

Referring now to FIG. 5B, there is illustrated yet another embodiment of the top of container 50 where container 50 does not taper near the top and cap 52 is yet larger. Also shown are threads 51B by which cap 52 is secured to body 51. Cap 52 includes lid 52A and opening 52C.

Those skilled in the art understand that these examples are illustrative of the invention and that many other configurations of shapes, size, and usage can be extrapolated from these descriptions.

These descriptions illustrate the advantages of the invention. For example, a significant advantage is convenience. When two materials are needed for a task, the complementary materials are always together and ready for use. One material is never misplaced.

Other significant advantages are space savings and reducing waste. Space is saved on restaurant tables, on store shelves, in warehouses, and in shipping. Waste is reduced because the two materials are packaged in proportions such that both materials will be completely used simultaneously.

The method of the invention follows from the description of the apparatus above. The method steps comprise:

Providing a dual ended container comprising a first compartment and a second compartment, said container having a first opening in a first end and a second opening in an opposing second end;

Providing a first cap and a second cap, said first cap forming a supporting surface for said dual ended container when it is attached to said first end;

Providing a first complementary material;

Placing said first complementary material into said first compartment;

Attaching said first cap to said first end of said container;

Providing a second complementary material;

Placing said second complementary material into said second compartment;

Attaching said second cap to said second end of said container;

Wherein said first and said second compartments of said dual ended container are detachably secured together;

Providing wrapping material; and,

Applying said wrapping material to the exterior of said first and said second compartments.

Alternate embodiments include the steps of wherein said first and said second compartments are detachably secured together using a perforated belt; and,

Wherein said first and said second compartments are detachably secured together with a twist-lock mechanism.

The specific configurations and features of the invention may vary according to specific requirements. In the preferred embodiment, the invention is generally used by consumers. However, the invention may be adapted to various applications in business, restaurants, and industry. Further, although only a few embodiments of the invention have been illustrated, it is understood that many adaptations of the invention may be implemented without departing from the spirit of the invention.

The solutions offered by the invention disclosed herein have thus been attained in an economical, practical, and facile manner. To whit, a novel container and method of use which is cost effective, convenient and easily adapted to many types of materials has been invented. While preferred embodiments and example configurations of the inventions have been herein illustrated, shown, and described, it is to be appreciated that various changes, rearrangements, and modifications may be made therein, without departing from the scope of the invention as defined by the claims. It is intended that the specific embodiments and configurations disclosed herein are illustrative of the preferred and best modes for practicing the invention, and should not be interpreted as limitations on the scope of the invention as defined by the claims, and it is to be appreciated that various changes, rearrangements, and modifications may be made therein, without departing from the scope of the invention as defined by the claims.

Claims

1. A dual sided container comprising:

a body having a first end and a second end;

a first opening located in said first end;

a second opening located in said second end;

a first cap secured to said first end and covering said first opening;

a second cap secured to said second end and covering said second opening; and,

wherein said first cap forms a supporting surface for said dispensing container.

2. The dual sided container according to claim 1:

wherein said body includes,

a first compartment for holding a first material; and,

a second compartment for holding a second material.

3. The dual sided container according to claim 2 wherein said first compartment is detachably secured to said second compartment.

4. The dual sided container according to claim 3 further comprising a wrapper in contact with the exteriors of said first compartment and said second compartment.

5. The dual sided container according to claim 4 wherein said wrapper is shrink wrap material.

6. The dual sided container according to claim 5 wherein said wrapper includes at least one perforation suitable for facilitating the separation of said first compartment from said second compartment.

7. The dual sided container according to claim 3 wherein said body includes a plurality of perforations located proximate to the junction of said first and said second compartments.

8. The dual sided container according to claim 3 wherein said body includes a perforated belt attached between said first compartment and said second compartment.

9. The dual sided container according to claim 8 wherein said perforated belt includes a pull tab.

10. The dual sided container according to claim 3 wherein,

said first compartment includes a male connector;

said second compartment includes a female connector; and,

said male connector is coupled with said female connector.

11. The dual sided container according to claim 2 further comprising an internal divider attached to the interior of said body and dividing the interior of said body into a first compartment and a second compartment.

12. The dual sided container according to claim 2 wherein said first compartment is larger than said second compartment.

13. A dispensing container comprising:

a first compartment having a first opening;

a second compartment secured to said first compartment and having a second opening;

a first cap attached to said first compartment and covering said first opening, said first cap having a supporting surface for supporting said dispensing container;

a second cap attached to said second compartment and covering said second opening; and,

wherein said first end and said second end are at opposing ends of said dispensing container.

14. The dispensing container according to claim 13 further comprising an internal divider secured between said first compartment and said second compartment.

15. The dispensing container according to claim 13, wherein said first and said second compartments are detachably secured together.

16. The dispensing container according to claim 15, further comprising a wrapper attached to the exterior of said first and said second compartments and securing said first and said second compartments together.

17. The dispensing container according to claim 16 wherein said wrapper includes at least one perforation suitable for facilitating the separation of said first compartment from said second compartment.

18. The dispensing container according to claim 16 wherein said wrapper is shrink wrap material.

19. The dispensing container according to claim 15, further comprising a perforated belt secured between said first and said second compartments and securing said first and said second compartments together.

20. The dispensing container according to claim 19 wherein said perforated belt includes a pull tab.

21. The dispensing container according to claim 15:

wherein said first compartment includes an interlocking appendage;

said second compartment includes an interlocking aperture suitable for coupling with said appendage; and,

wherein said interlocking appendage is secured in said interlocking aperture.

22. A method of holding two complementary materials comprising the steps of:

providing a dual sided container comprising a first compartment and a second compartment, said container having a first opening in said first compartment and a second opening in said second compartment;

providing a first cap and a second cap, said first cap forming a supporting surface for said dual sided container when it is attached to said first compartment;

providing a first complementary material;

placing said first complementary material into said first compartment;

attaching said first cap to said first compartment;

providing a second complementary material;

placing said second complementary material into said second compartment; and,

attaching said second cap to said second compartment.

23. The method according to claim 22 wherein said first and said second compartments of said dual sided container are detachably secured together.

24. The method according to claim 23 further comprising the steps of

providing wrapping material; and,

applying said wrapping material to the exterior of said first and said second compartments.

25. The method according to claim 23 wherein said first and said second compartments are detachably secured together by a perforated belt.

26. The method according to claim 23 wherein said first and said second compartments are detachably secured together with a twist-lock mechanism.