US20100005633A1

US20100005633A1 - Method for designing detachable objects using magnetic holding force

Info

Publication number: US20100005633A1
Application number: US12/168,982
Authority: US
Inventors: Julianne Nolet
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-07-08
Filing date: 2008-07-08
Publication date: 2010-01-14

Abstract

Provided is a method for designing a detachable object to an item by setting design objectives including a magnetic holding force objective needed to hold the detachable object to the item. A set of magnetic pieces are selected based on the holding magnetic force objective. An outer magnetic piece is fabricated onto the detachable object and an inner magnetic piece is fabricated and positioned within the item. The selection of the magnetic set and/or the position of the outer and inner magnetic pieces are modified until the design objectives are met.

Description

BACKGROUND

1. Field
The present application generally relates to the design of detachable objects, more particularly, to a method of designing detachable objects using magnetic holding force that meet one or more design objectives.
2. Related Art
Detachable objects are used extensively in jewelry and ornaments. Pendant connectors, permanent magnet rings, and magnetic necklace clasps are known in the prior art. Most of the magnetic necklace clasp specifies the use of a magnet that remain magnetized in the face of stray magnetic fields, mechanical movement or shock, and a range of temperatures. These magnets are known as permanent magnets. There are three types of permanent magnets currently in use; alnicos, hard ferrites, and rare-earth magnets. Two types of commercially available rare-earth magnets, neodymium-iron-boron (Nd—Fe—B) and samarium cobalt (SmCo), are much stronger permanent magnets than alnicos or hard ferrites. A hard ferrite magnet would have to be ten times the size of either of these rare-earth magnets to achieve the same pull force.
A magnet's holding strength derives from the magnet's atomic structure and from the magnet's method of manufacture. A samarium cobalt magnet holds its standard property in higher maximum temperatures than a neodymium-iron-boron magnet, but the neodymium magnet achieves a higher maximum energy product as measured in megagauss-oersteds. Samarium cobalt is more brittle than neodymium-iron-boron and more expensive because samarium is the least abundant of the light rare-earth elements. Sintered neodymium-iron-boron magnets processed by a melting method are about three times stronger than bonded neodymium-iron-boron magnets processed by a gluing method. Because magnetic pull force, cost, and stability are the most relevant factors to magnets used in jewelry production, sintered neodymium-iron-boron magnets are practical magnets to use in manufacturing a convertible magnetic pendant clasp necklace. The use of relatively strong magnetic materials permits less magnetic material to be used to achieve the same magnetic strength than if weaker magnetic material were used.
One limitation of known magnetic detachable objects is their inability to serve as a mount for ornaments. For example, a magnetic clasp must have a flat center if it is to serve as such a mount. If the clasp has a center that is not flat or if the center is uneven in any way due to the presence of integrated latches or release devices, pendant items will tilt or fall off when bumped. Another problem typically encountered with detachable objects especially objects used as jewelry or other consumer items is the requirement for making the item both aesthetic and comfortable for the user of the item. There is a need for a method of designing detachable objects using magnetic force that will keep the objects attached to the item under normal intended use while meeting aesthetics and functionality objectives.

SUMMARY

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is an architectural diagram illustrating an exemplary embodiment where the holding force for detachable objects utilizes a set of magnets; FIG. 1B depicts a graph of magnetic flux density versus distance from the magnet; and FIG. 1C depicts a graph of pull force versus the distance from the magnet.

FIG. 2A depicts an architectural diagram of an exemplary embodiment where the inner magnetic piece of the set of magnetic pieces is positioned within the item whereas FIG. 2B depicts an architectural diagram or an exemplary embodiment where inner magnetic piece is positioned in between layers of material within the item.

FIG. 3 depicts an architectural diagram of exemplary embodiments securing the outer magnetic piece to the detachable object.

FIG. 4 depicts an exemplary cross sectional view of embodiments of detachable objects with a plurality of arrangements of the outer magnetic pieces and inner magnetic pieces.

FIG. 5 depicts an exemplar flowchart for designing and testing detachable objects using magnetic holding force.

FIG. 6 depicts exemplary diagrams of items utilizing magnetic holding force for detachable objects.

DETAILED DESCRIPTION

In order to facilitate the description of the present invention, a detachable object for a shoe is utilized to illustrate an application of the concept.
FIG. 1A is an architectural diagram illustrating an exemplary embodiment where the holding force for detachable objects utilizes a set of magnets. The item 100 may be a shoe, handbag, purse, hat, cap, jacket, boot, suitcase, briefcase, belt, or a consumer item not sensitive to magnets. Item 100 may also be a commercial item or industrial item not sensitive to magnets but requiring one or more detachable objects 120. The detachable object 120 comprises an ornament 104 and an outer magnetic piece 108. The ornament 104 may be jewelry or a decorative piece. In one embodiment, the ornament 104 is made of precious metals such as gold, silver, platinum or the like. In another embodiment, the ornament 104 utilizing one or more combination of precious metals may be adorned with diamonds and/or gemstones. The outer magnetic piece 108 is coupled to the ornament 104 using mechanical means or by using bonding agents. Mechanical means include use of clips or applying a layer of plating on the outer magnetic piece 108 that keeps the outer magnetic piece 108 attached to the ornament 104. Bonding agents may include metal to metal adhesives or bonding compounds. The outer magnetic piece 108 may be coupled to the ornament 104 with the outer magnetic piece 108 as a base of the ornament 104 or inside a cavity (not shown) in the ornament 104 such the outer magnetic piece 108 is flush to the bottom surface of the ornament 104.
The outer magnetic piece 108 may be one or more types of magnet or one or more pieces of permanent magnets bonded together or may be an electro magnet powered by batteries. In one embodiment, the outer magnetic piece 108 may comprise magnets including rare earth, ceramic, or industrial magnets. Rare earth magnets may include neodymium or samarium cobalt magnets. Neodymium magnets are powerful permanent magnets and are also referred to as NdFeB magnets, or NIB, because they are composed mainly of Neodymium (Nd), Iron (Fe) and Boron (B). Neodymium magnets are typically over ten times stronger than the strongest ceramic magnets. The material of the item 112 separates the outer magnetic piece 108 from the inner magnetic piece 116. The inner magnetic piece 116 may comprise magnets including rare earth, ceramic, or industrial magnets. Similar to the outer magnetic piece 108, the inner magnetic piece 116 may comprise one or more pieces of permanent magnets bonded together or may be an electro magnet powered by batteries. In one embodiment, either the inner magnetic piece 116 or the outer magnetic piece may be a ferromagnetic material such as iron, cobalt, nickel, or various alloys including iron, cobalt, and/or nickel.
For applications that require high holding magnetic force, neodymium magnets may be used in both the outer magnetic piece 108 and the inner magnetic piece 116. The selection of the outer magnetic piece 108 and the inner magnetic piece 116 will be discussed below. Commercially available neodymium magnets are made from a powdered mixture that is pressed under great pressure into molds. The material is then sintered (heated under a vacuum), cooled, and then ground or sliced into the desired shape. Coatings are then applied if required. Finally, the blank magnets are magnetized by exposing them to a very powerful magnetic field in excess of 30,000 Oersted. Typical neodymium magnets are plated with layers of nickel, copper, and nickel again. This triple coating makes neodymium magnets more durable than the more common single nickel plated magnets. Some other options for coating are zinc, tin, copper, epoxy, silver, and gold. Gold plated magnets are actually quadruple plated with nickel, copper, nickel and a top coating of gold.
FIG. 1B depicts a graph 150 of magnetic flux density in the Y-axis versus distance from the magnet in the X-axis. Flux density is typically measured in millions of Gauss Oersted (MGOe). The flux density curve 154 depicts the flux density of a specific magnet as a function of distance from the magnet. For example, at point A in the flux density curve 154, the flux density is 1.7 MGOe for a distance of 6 millimeters from the magnet. The graph 150 of the flux density diminishes quickly as the distance from the magnet increases. In embodiments using neodymium, the strength of neodymium magnets is expressed in the grade, or “N rating” of the magnet, referring to the Maximum Energy Product of the material that the magnet is made from or the maximum strength that the neodymium can be magnetized to. The grade of neodymium magnets is generally measured in units millions of Gauss Oersted (MGOe). A magnet of grade N42 has a Maximum Energy Product of 42 MGOe. Generally speaking, the higher the grade, the stronger the magnet. The highest grade of neodymium magnet currently available is N52 but magnet manufacturers are continuously discovering newer manufacturing techniques and processes to produce newer and stronger magnets.
The strength of a magnet is also measured in pull force defined as the holding force of a magnet that is in contact with a flat steel plate. Pull forces are measured in pounds or kilograms. FIG. 1C depicts a graph 180 of pull force in the Y-axis versus distance from the magnet in the X-axis. The pull force curve 184 depicts for a given magnet the pull force in pounds as a function of the distance from the magnet in inches. The pull force curve 184 drops very quickly with the increase in distance. For example, point B in the pull force curve 184, the magnet is rated at 35 pounds and at point C, the magnet is rated at less than 10 pounds after moving 0.05 inch from point of contact.
FIG. 2A depicts an architectural diagram of an exemplary embodiment where outer magnetic piece 214 of detachable object 220 comprises two magnets and the inner magnetic piece 222 is positioned within the item 200. The material 210 of the item 200 is subjected to the magnetic pull force of the outer magnetic piece 214 and the inner magnetic piece 222. The ornament 218 includes a cavity 234 filled with the two magnets of the outer magnetic piece 214 where the bottom surface of outer magnetic piece 214 is flush with the upper surface of the material 210. In one embodiment where the item is a shoe, hat, or jacket, the inner magnetic piece 222 may be wrapped in soft plastic or laminated with plastic or other material (not shown) in order to make the item more functional. In one embodiment, the cavity 234 is disc shaped and is between 0.50 to 0.75 inches in diameter and the thickness of the cavity 234 is 1/16 to 1/10 of an inch, depending on the pull force needed for the outer magnetic piece 214. The outer magnetic piece 214 can be one disc magnet instead of several stacked disc magnets. The cavity 234 can he shaped like a disc, block, ring, arc, or half of a sphere.
As mentioned above, the outer magnetic piece 214 can be attached to the ornament 218 using metal adhesives or epoxy such as J-B Weld epoxy from J-B Weld Company. J-B Weld epoxy uses a liquid steel/epoxy resin and a hardener. The mixture comprising the epoxy and the hardener sets in 4 to 6 hours and cures fully in 15 to 24 hours. In one embodiment, the cavity 234 is cleaned with a solvent such as acetone, ethyl acetate, or the like and left to dry. The side of the outer magnetic piece 214 to be attached to the ornament 218 in the cavity 234 is lightly sanded to create a better bonding texture. The epoxy resin is then mixed with the hardener, creating a chemical reaction that turns the mixture into a hard compound after a curing process. This compound is placed inside the recessed cavity 234 of the ornament 218 and the outer magnetic piece 214 is placed inside the cavity 234. The compound covers the lower side and the surrounding edges of the outer magnetic piece 214 for a better hold. Once cured, the bottom area of the outer magnetic piece 214 and proximate area of the ornament 218 are lightly sanded to create a smooth and even surface and appropriate color paint is applied to cover the color of the compound. Other metal adhesives and hardening materials may be used. If the ornament 218 is made of gold, silver, platinum, or alloys, then an appropriate metal paint is used to make ornament 218 and the outer magnetic piece 214 blend in color and texture.
FIG. 2B depicts an architectural diagram of an exemplary embodiment where inner magnetic piece 222 is positioned in between layers 226 and 230 of material 210 within the item 250. For example, in the case where the ornament 218 is jewelry and the item 250 is a shoe, the inner magnetic piece 222 is inserted between two materials 226 and 230 of the shoe 250. In another example where the item 250 is a briefcase, the inner magnetic piece 222 is inserted between two materials 226 and 230 of the briefcase.
FIG. 3 depicts an architectural diagram of an exemplary embodiment where the outer magnetic piece 308 is secured to the detachable object 304. As mentioned above, the outer magnetic piece 308 can be attached to the detachable object 304 using a disc magnet with or without using a cavity as in 3A or by using a block magnet with or without using a cavity as in 3B or by using a ring magnet with or without using a cavity as in 3C or using a strip magnet with or without using a cavity as in 3D or by using a wire magnets with or without using a cavity as in 3E. To one knowledgeable in the art, other variations of the shape and method of attachment of the outer magnetic piece to the ornament exist that are within the scope and concepts of the invention.
FIG. 4 depicts an exemplary cross sectional view 400 of the embodiments of detachable objects with a plurality of arrangements of outer magnetic pieces and inner magnetic pieces. In 4A, the detachable object 414 comprising the ornament 404 and the outer magnetic piece 406 utilizes a single block magnet attached to the ornament 404 where the inner magnetic piece 410 comprises three magnets enclosed in container 412 and placed against the material 408 of item 414. In one example, the item 400 may be a briefcase or luggage piece where the inner magnetic piece 410 comprises three magnets inside an container 412, attached to the inside of the briefcase or luggage piece. In 4B, arc magnets are used. These are special magnets where the magnetic blanks are radially magnetized. The outer magnetic piece 426 is attached to the ornament 424 where the arc angle follows the outer curvature of the material 428 of the item 420. Similarly, the inner magnetic piece 430 can be an arc magnet where the arc angle follows the inner curvature of the material 428 of the item 420. In 4C, the outer magnetic piece 466 comprises three magnets attached to the ornament 464 to form the detachable object 474. The inner magnetic piece 470 comprises a magnetic sheet or flexible magnetic slab positioned against the material 468 of the item 460. An inner magnetic piece 470 in the form of a magnetic sheet or flexible magnetic strip provides flexibility in positioning the detachable object 474 anywhere in the area covered by the inner magnetic piece 470. To one knowledgeable in the art, other variations of the configuration and number and shape of the outer and inner magnetic pieces exist that are within the scope and concepts of the invention.
FIG. 5 depicts an exemplary flowchart for designing and testing detachable objects using magnetic holding force. In step 500, design objectives for a detachable object are set. The design objectives can include a holding force that keeps the detachable object attached to the item. The holding force may be based on empirical data correlating the weight and size of the detachable object and distance of the outer magnetic piece to the inner magnetic piece to the effective holding force of the magnetic set. Magnetic holding force may be expressed as effective pull force or magnetic flux density and the distance to the magnet as depicted in the graphs in FIGS. 1B and 1C. Other design objectives for the detachable object may include aesthetic appeal especially for jewelry, and decorative items. Another design objective may be functionality, defined as the ability of the item in the presence of the detachable object(s) allowing unimpeded use of the item for its normal intended purpose. For example, if the detachable object is jewelry or decorative article for a shoe, the detachable jewelry or decorative article and the attachment technique should allow for regular normal use of the shoe. In step 504, a magnetic set is selected based on the initial holding force objective. The magnetic set comprises the outer and inner magnetic pieces. As mentioned above, the outer or the inner magnetic piece may include one or more magnets. Furthermore, the outer magnetic piece may be a ferrite material, i.e., attracted to magnets such as iron, copper, nickel, or alloys including at least one of iron, copper, or nickel. Similarly, the inner magnetic piece may be a magnet or a ferrite material. The shape and dimensions of the outer and inner magnetic pieces are determined based on the type and number of detachable objects designed for the item. In one embodiment, the item is a shoe and the detachable object is jewelry. The jewelry may use gold, silver, platinum, or the like and may be adorned with diamonds and/or precious stones. The outer magnetic piece can include a neodymium block or disc magnet or an electromagnet and the inner magnetic piece may be a disc neodymium magnet or a ferrite material. In another embodiment, the item is a bag or purse and the detachable object is a set of decorative jewelry. The outer magnetic piece can be a set of magnets, one for each piece of decorative jewelry and the inner magnetic piece can be a flexible sheet of rare earth magnet such as neodymium or samarium cobalt magnets or a flexible sheet of ferrite material placed in between layers of the material of the bag or purse.
In step 508, the process of attaching the outer magnetic piece is determined. As mentioned above, the outer magnetic piece may be attached to the ornament using the appropriate adhesive. In one embodiment, a cavity is used for attaching the outer magnetic piece to the ornament. If the detachable object is jewelry or decorative article, a cavity may be utilized to conceal or minimize the profile of the outer magnetic piece, thus enhancing the aesthetic appeal of the detachable object. The outer magnetic piece may be placed in a cavity slightly larger than the outer magnetic piece, attached to the ornament with metal adhesive, where the exposed side of the outer magnetic piece is lightly sanded and painted with appropriate paint to match or complement the color of the ornament. In another embodiment, instead of painting, the exposed side of the outer magnetic piece is covered with plating material such as gold, silver, or platinum and the like. In step 512, the design and positioning of the inner magnetic piece is determined. The design and positioning of the inner magnetic piece is based on the intended normal use of the item. For example, if the item is a shoe, the inner magnetic piece needs to be easy to position and must not impede in the use of the shoe. In one embodiment where the item is a shoe, the inner magnetic piece is a neodymium disc magnet with a diameter of ½ to ¼ inch and thickness of 1/32 to 1/16 of an inch and the magnet is placed inside the shoe on top of the foot. Alternatively, the magnet may be taped inside the shoe proximate to the position of the detachable object.
In step 516, the outer magnetic piece is fabricated onto the detachable object using the design determined in step 508. In step 520, the inner magnetic piece is fabricated onto the item or positioned on the item. If the inner magnetic piece is a sheet of ferrite material or a magnetic sheet, the inner magnetic piece can be attached to the item or fabricated in between layers of material of the item. If the inner magnetic piece was designed to be placed on or taken off, then the inner magnetic piece is positioned as designed in step 512. For example, it the item is a shoe and the detachable object is jewelry or decorative article, this step can be positioning the inner magnetic piece inside the shoe on top of the foot. In step 524, the performance of the detachable object is compared to the design objectives. For example, if the design objectives of a detachable object include a holding force of 50 pounds for the detachable object such as shoe jewelry and functionality as a shoe, these objectives are compared with the actual performance of the shoe jewelry. If the objectives are not met, the design of the magnetic set, i.e., the outer and inner magnetic pieces are modified and processes in steps 508, 512, 516, 520, and 524 are iterated until the design objectives are met.
FIG. 6 depicts exemplary diagrams of sample items 600 utilizing magnetic holding force for detachable objects. Several items are depicted that may use one or more detachable objects. One item 610 is a shoe 614 shown with one detachable object 618 where the inner magnetic piece (not shown) would be placed by wearer on top of the foot proximate to detachable object 618. Other items depicted, 630, 650, and 670, illustrate a handbag 634, a briefcase 654, and a hat 674 and a plurality of detachable objects, 638, 658, and 678 respectively. Many others such as caps, jackets, boots, belts, and other consumer items may be accentuated with detachable objects using the principles and concepts of the present invention. Other applications including commercial and/or industrial items such as appliances and furniture can also be adorned with detachable objects.
Although exemplary embodiments have been described, various modifications can be made without departing from the spirit and/or scope of the present invention. For example, mobile and regular phones may utilize detachable objects. Interiors and exteriors of cars and recreational items such as motorcycles, and boats may use the concepts and principles described with the present invention. Therefore, the present invention should not be construed as being limited to the specific forms shown in the drawings and described above.

Claims

1. A method of designing a detachable object for an item, the method comprising:

setting one or more design objectives for designing a detachable object for an item using magnetic force wherein one objective is a holding magnetic force objective;

selecting a magnetic set based on the determined holding magnetic force, the magnetic set including an outer magnetic piece and an inner magnetic piece;

determining a process of attaching the outer magnetic piece to the detachable object;

determining a design and position of the inner magnetic piece in the item;

fabricating the outer magnetic piece onto the detachable object and positioning the inner magnetic piece in the item;

if the one or more design objectives are not met, modifying the selection of the magnetic set and/or position of the inner magnetic piece and iterating determining the process of attaching the outer magnetic piece onto the detachable object, determining the design and position of the inner magnetic piece in the item, fabricating the outer magnetic piece onto the item and positioning the inner magnetic piece until the one or more design objectives are met.

2. The method of claim 1 wherein the holding magnetic force is provided by neodymium magnets, samarium cobalt magnets, or electro magnets.

3. The method of claim 2 wherein the neodymium magnets have a rating of N42, N50, or higher.

4. The method of claim 1 wherein the item is a shoe and the detachable object is shoe jewelry.

5. The method of claim 4 wherein the outer magnetic piece is a disk neodymium magnet.

6. The method of claim 4 wherein the outer magnetic piece is a square, ring, strip, rectangular, or cylindrical neodymium magnet.

7. The method of claim 1 wherein the inner magnetic piece is a disc or block neodymium magnet securely positioned between two layers of materials of the shoe.

7. The method of claim 1 wherein the inner magnetic piece is disc or plate neodymium magnet varying in thickness from 1/16 inch thickness to 1/32 inch thickness or less.

8. The method of claim 1 wherein the inner magnetic piece is a flexible sheet of neodymium magnet.

9. The method of claim 1 wherein the inner magnetic piece is ferrite magnet or a flexible sheet of ferrite material.

10. The method of claim 1 wherein the fabricating the outer magnetic piece onto the detachable object comprises:

creating a cavity in the detachable object wherein the cavity is slightly larger than the outer magnetic piece; and

attaching the outer magnetic piece to the detachable object using the cavity.

11. The method of claim 10 wherein the outer magnetic piece is attached to the detachable object using metal adhesive.

12. The method of claim 1 wherein the outer magnetic piece comprises two or more neodymium magnets attached to the detachable object.

13. The method of claim 1 wherein the detachable object is jewelry made of gold, silver, platinum, or any combination of the foregoing.

14. The method of claim 1 wherein the detachable object is jewelry made of precious metals or jewelry made of precious metals decorated with diamond and/or gemstones.

15. The method of claim 1 wherein the item is a shoe, handbag, purse, hat, cap, jacket, boot, suitcase, briefcase, or belt.

18. The method of claim 1 wherein the outer magnetic piece is painted with a color substantially close to the color of the surrounding portions of the detachable object.

17. The method of claim 1 wherein modifying the selection of the magnetic set and/or position of the inner magnetic piece includes changing the thickness of the inner magnetic piece or changing the inner magnetic piece to a sheet magnet or flexible magnet.

18. An apparatus fabricated to keep a detachable object attached to an item under normal intended use, the system comprising:

an item having a normal intended use;

a detachable object configured to be attached to the item using a set of magnetic pieces, the set of magnetic pieces comprising:

an outer magnetic piece coupled to the detachable object; and

an inner magnetic piece positioned within the item;

wherein the outer magnetic piece and the inner magnetic piece are configured to generate a holding magnetic force sufficient to keep the detachable object attached to the item under normal intended use.

19. The apparatus of claim 18 wherein the holding magnetic force is provided by neodymium magnets, samarium cobalt magnets, or electro magnets.

20. The apparatus of claim 18 wherein the neodymium magnets have a rating of N42, N50, or higher.

21. The apparatus of claim 18 wherein the item is a shoe and the detachable object is shoe jewelry.

22. The apparatus of claim 18 wherein the outer magnetic piece is a disk neodymium magnet or block neodymium magnet.

23. The apparatus of claim 18 wherein the outer magnetic piece is a square, ring, strip, rectangular, or cylindrical neodymium magnet.

24. The apparatus of claim 18 wherein the inner magnetic piece is a disc neodymium magnet securely positioned between two layers of materials of the item.

25. The apparatus of claim 18 wherein the inner magnetic piece is flexible sheet neodymium magnet or wherein the inner magnetic piece is a ferrite magnet or a flexible sheet of ferrite material.

26. The apparatus of claim 18 wherein outer magnetic piece is coupled to the detachable object by creating a cavity in the detachable object wherein the cavity is slightly larger than the outer magnetic piece.

27. The apparatus of claim 18 wherein the outer magnetic piece is attached to the detachable object using epoxy resin and a hardener.