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Magnetic fasteners

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US2742250A
US2742250A US27864052A US2742250A US 2742250 A US2742250 A US 2742250A US 27864052 A US27864052 A US 27864052A US 2742250 A US2742250 A US 2742250A
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magnetic
fastener
shank
fig
pole
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Luther C Cronberger
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Luther C Cronberger
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    • AHUMAN NECESSITIES
    • A47FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
    • A47GHOUSEHOLD OR TABLE EQUIPMENT
    • A47G1/00Mirrors; Picture frames or the like, e.g. provided with heating, lighting or ventilating means
    • A47G1/16Devices for hanging or supporting pictures, mirrors, or the like
    • A47G1/17Devices for hanging or supporting pictures, mirrors, or the like using adhesives, suction or magnetism
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T24/00Buckles, buttons, clasps, etc.
    • Y10T24/32Buckles, buttons, clasps, etc. having magnetic fastener

Description

p 17, 1956 1.. c CRONBERGER MAGNETIC FASTENERS Filed March 26, 1952 INVENTOR mm c. GRONBERGER W ATTORNEY United States Patent 2,742,250 MAGNETIC FASTENERS Luther C. Cronberger, Tulsa, Okla.

Application March 26, 1952, Serial No. 278,640

1 Claim. (Cl. 248206) This invention relates to fasteners in general, more particularly to fasteners of the magnetic type, and the present patent application is a continuation-in-part of my co-pending patent application Serial No. 223,991, filed May 1, 1951, now abandoned.

A general object of my invention is to provide an improved fastener for supporting magnetizable objects on nonmagnetic structures.

A more specific object of my invention is to provide a fastener which can be secured to any desired nonmagnetic structure in the way of a tack and which has a high magnetic attractive power enabling it to firmly support against the action of gravity many different kinds of magnetizable objects.

Another object of my invention is to provide a magnetic fastener including a permanent magnet and a mag netic pole piece for the permanent magnet adapted to support magnetizable objects by magnetic attraction at a surface which is considerably larger than the cross-sectional area of the permanent magnet.

Further objects and advantages will readily become apparent upon a reading of the following specification taken in conjunction with the drawing, in which:

Fig. 1 is a cross-section of a magnetic fastener and a magnetizable object which is being supported by it against the action of gravity;

Fig. 2 shows the same structure as Fig. 1 in front view;

Fig. 3 is a top-plan view of a modified magnetic fastener;

Fig. 4 is a side view, partly in cross-section, of the fastener shown in Fig. 3; and

Figs. 5 and 6 are sectional front views of two magnetic fasteners in the shape of tacks.

According to this invention a magnetic fastener comprises a substantially rod-shaped element approximately of the same size, length and cross-sectional area as the shank of a small nail or screw. This rod-shaped element is arranged, or intended to be arranged in a bore provided in a nonmagnetic structure, e. g. of a wooden structure, and securely held therein. The magnetic fastener comprises also a magnetic head of considerably shorter length than the above referred-to rod-shaped element coaxially arranged immediately adjacent to one end of said rod-shaped element in engagement with the above referred-to nonmagnetic structure. Said magnetic head has a surface remote from said rod-shaped element having a considerably larger area than the cross-sectional area of said rod-shaped element. An object of magnetizable material is in physical engagement with and supported against the action of gravity by said magnetic head and the area of physical engagement between said head and said object exceeds the cross-sectional area of said element.

Referring now to the drawing, and more particularly to Figs. 1 and 2 thereof, reference numeral 1 designates a fixed structure of nonmagnetic material such as, for instance, wood. The structure to which numeral 1 has been applied may be considered to be a wooden panel.

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Four tacks, generally designated by numeral 2, are driven into the wooden structure 1. The heads 3 of tacks 2 have attractive magnetic power and firmly hold in position the iron or steel plate 5. Plate 5, in turn supports against the action of gravity a mirror 6, picture or the like which may be attached to its front surface by suitable adhesive means not shown. The shanks 4 of tacks 2 are formed by permanent bar magnets preferably made of a suitable aluminum nickel alloy such as that generally known in the trade as Alnico.

The fastener shown in Figs. 3 and 4 comprisesa small powerful permanent magnet 8 as, for instance, an Alnico rod of A inch diameter which is inserted into a hole 9 drilled into a block 1 of wood. The magnet 8 is loosely inserted into hole 9 but prevented from dropping out by a flat cap 10 which forms a pole piece for magnet 8. Magnet 8 is attracted to cap 10 and stays permanently in engagement therewith. The separate spherical cap 10 is cemented to block 1 by an adhesive 11.

The fasteners shown in Figs. 5 and 6 comprise a permanent shank-shaped magnet 8, preferably made of an aluminum nickel alloy and a head 10 made of a ferromagnetic material. Both may be bonded together by any suitable cement, i. c. any cement providing a sufficiently strong mechanical bond. The fastener shown in Fig. 5 has a spherically shaped hollow head of relatively thin cross-section and of such magnetic reluctance as to result in a substantial leakage flux along the surface thereof remote from shank 8. In the structure of Fig. 6 the magnetic head 10 is solid rather than hollow and most of the flux goes through the head, i. e. there is virtually no leakage flux at the surface of head 10 remote from shank 8. Some flux lines have been shown in Figs. 5 and 6 and indicated by reference letter F. Inasmuch as it is desired to cause the flux F originating at one pole of shank 8 to flow through another structure before returning to the other pole of shank 8, the arrangement of Fig. 5 is more desirable than that of Fig. 6. Accordingly the heads of the fasteners shown in Figs. 1 to 4, inclusive, should be hollow, as shown in Fig. 5.

It is possible and desirable to make up shank 8 of two parts, i. e. of an inner core element which is a permanent magnet and an outer sleeve element which is nonmagnetic and adapted to be driven into a Wooden or the like nonmagnetic body. The sleeve element may be screw-threaded, if desired.

It will be observed from the foregoing that the magnetic portion of my fasteners intended to be in physical engagement with the object to be supported by magnetic attraction is large, i. e. considerably larger than the cross-sectional area of the rod-shaped portion of the fastener which projects into the nonmagnetic material by which the fastener is supported. This is an important feature because the holding power of the fastener increases within limits with the size of this area of engagement. For this reason the radius of curvature of the pole piece 10 should be relatively large, as best shown in Fig. 4. The joint magnetic flux through the permanent magnet 8 and the magnetic head or pole piece 10 is always sufficiently large to preclude relative movement under the actions of gravity and accidental impact forces between said pole piece and the object of magnetizable material which is being supported by it.

The geometrical configuration of the magnetic field is different depending upon whether the pole piece is fiat or convex, as shown in Figs. 3 to 6. I have found that the convex type of pole piece is preferable, i. e. that fasteners which are provided with convex pole pieces have a considerably increased attractive or holding power. In such pole pieces the holding surface follows more closely an equipotential plane, resulting in a more even distribution of the magnetic flux over the holding surface,

Whereas if the holding surface is flat, this tends to result in an undue concentration of the magnetic flux along the circumference of the pole piece.

Although I have shown and described specific structures it is to be clearly understood that the same were merely for the purpose of illustration and that changes and modifications may readily be made herein by those skilled in the art Without departing from the spirit and scope ofthe appended claim.

I claim as my invention:

A magnetic fastener comprising a shank portion and a separate spherical hollow head portion in abutting relation with said shank portion, said shank portion consisting of a permanently magnetic material and said head 4 portion consisting of a magnetizable sheet material magnetized by said shank portion to such high degree of saturation as to result in a substantial leakage flux along the surface thereof remote from said shank portion.

References Cited in the file of this patent UNITED STATES PATENTS 32,527 Nichols et'al. June 11, 1861 10 2,203,580 Ronning June 4, 1940 2,495,644 Rowley Ian. 24, 1950 2,510,634 Hull June 6, 1950 2,570,626 Abraham Oct. .9, 1951 2,627,778 Hodell Feb. 10, 1953

US2742250A 1952-03-26 1952-03-26 Magnetic fasteners Expired - Lifetime US2742250A (en)

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Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2960924A (en) * 1957-11-14 1960-11-22 Frank S Grott Air distributing conduit system for portable air conditioners
US2975880A (en) * 1954-11-16 1961-03-21 Rowe Mfg Co Inc Coin separator and slug ejector
US3196548A (en) * 1963-02-04 1965-07-27 Harold C Moore Measuring device
US3332373A (en) * 1966-08-10 1967-07-25 Ruiz Leon Drop leaf tables
US3332695A (en) * 1965-01-26 1967-07-25 Kenneth P Rosenberg Magnetic ski bindings
US3357712A (en) * 1965-01-26 1967-12-12 Kenneth P Rosenberg Magnetic ski bindings
US3384934A (en) * 1965-12-16 1968-05-28 Elton Ind Inc Magnetic fastener
US3661048A (en) * 1969-06-16 1972-05-09 Town Line Erection Co Inc Fastening means for structural members
US3668624A (en) * 1969-11-20 1972-06-06 Novatek Inc Method and apparatus for vehicle control and guidance
US4211382A (en) * 1977-10-20 1980-07-08 Bonfils Robert J Picture frame retainer
US4875654A (en) * 1987-12-29 1989-10-24 Yvon Chandoneet Magnetic picture retainer
US6305656B1 (en) 1999-02-26 2001-10-23 Dash-It Usa Inc. Magnetic coupler and various embodiments thereof
US6484996B2 (en) * 2000-03-13 2002-11-26 Benjamin F. Astell Device for removably fastening a picture to a board
US20050006552A1 (en) * 2003-07-11 2005-01-13 Edward Giles Soft pad picture mount
US20070245613A1 (en) * 2006-03-21 2007-10-25 Williams Matthew V Image display device with permanently incorporated pins
US20080005873A1 (en) * 2006-07-06 2008-01-10 Helen Of Troy Limited Magnetic pushpin
US20100242230A1 (en) * 2009-03-27 2010-09-30 Saul Cohen Clothing fasteners
US20110042542A1 (en) * 2008-01-22 2011-02-24 Russo Kelley M Magnet-based mounting systems for frames
WO2013068582A2 (en) * 2011-11-11 2013-05-16 Meredith Yates Magnetic attachment system
US8695934B2 (en) 2010-11-03 2014-04-15 Palm Coast Imports Llc Remote control unit wall docking system
US9328754B2 (en) 2013-01-02 2016-05-03 K & K Products, Llc Fastener
US20160138630A1 (en) * 2013-12-26 2016-05-19 Fujikin Incorporated Lower member fixing device and fluid control device provided with the same
US20170037614A1 (en) * 2015-08-06 2017-02-09 Hydra Heating Industries, LLC Magnetic clasps for insulation
US9589461B1 (en) 2014-03-29 2017-03-07 Hkc-Us, Llc Battery powered wall mounted remote control for ceiling fans and lights
US20170173920A1 (en) * 2015-08-06 2017-06-22 Hydra Heating Industries, LLC Magnetic insulation
US9867754B2 (en) 2013-08-10 2018-01-16 Donald Burke Magnetic conveyance system

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US32527A (en) * 1861-06-11 Improved nail or screw head
US2203580A (en) * 1938-06-09 1940-06-04 Ronning Adolph Door catch
US2495644A (en) * 1948-01-16 1950-01-24 Chauncey L Rowley Holder for hairpins
US2510634A (en) * 1945-11-03 1950-06-06 Parker Pen Co Magnetic desk set
US2570626A (en) * 1947-03-06 1951-10-09 Ruberoid Co Roofing fastener
US2627778A (en) * 1949-06-14 1953-02-10 Nat Screw & Mfg Company Screw and cap

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US32527A (en) * 1861-06-11 Improved nail or screw head
US2203580A (en) * 1938-06-09 1940-06-04 Ronning Adolph Door catch
US2510634A (en) * 1945-11-03 1950-06-06 Parker Pen Co Magnetic desk set
US2570626A (en) * 1947-03-06 1951-10-09 Ruberoid Co Roofing fastener
US2495644A (en) * 1948-01-16 1950-01-24 Chauncey L Rowley Holder for hairpins
US2627778A (en) * 1949-06-14 1953-02-10 Nat Screw & Mfg Company Screw and cap

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2975880A (en) * 1954-11-16 1961-03-21 Rowe Mfg Co Inc Coin separator and slug ejector
US2960924A (en) * 1957-11-14 1960-11-22 Frank S Grott Air distributing conduit system for portable air conditioners
US3196548A (en) * 1963-02-04 1965-07-27 Harold C Moore Measuring device
US3332695A (en) * 1965-01-26 1967-07-25 Kenneth P Rosenberg Magnetic ski bindings
US3357712A (en) * 1965-01-26 1967-12-12 Kenneth P Rosenberg Magnetic ski bindings
US3384934A (en) * 1965-12-16 1968-05-28 Elton Ind Inc Magnetic fastener
US3332373A (en) * 1966-08-10 1967-07-25 Ruiz Leon Drop leaf tables
US3661048A (en) * 1969-06-16 1972-05-09 Town Line Erection Co Inc Fastening means for structural members
US3668624A (en) * 1969-11-20 1972-06-06 Novatek Inc Method and apparatus for vehicle control and guidance
US4211382A (en) * 1977-10-20 1980-07-08 Bonfils Robert J Picture frame retainer
US4875654A (en) * 1987-12-29 1989-10-24 Yvon Chandoneet Magnetic picture retainer
US6305656B1 (en) 1999-02-26 2001-10-23 Dash-It Usa Inc. Magnetic coupler and various embodiments thereof
US6484996B2 (en) * 2000-03-13 2002-11-26 Benjamin F. Astell Device for removably fastening a picture to a board
US20050006552A1 (en) * 2003-07-11 2005-01-13 Edward Giles Soft pad picture mount
US20070245613A1 (en) * 2006-03-21 2007-10-25 Williams Matthew V Image display device with permanently incorporated pins
US20080005873A1 (en) * 2006-07-06 2008-01-10 Helen Of Troy Limited Magnetic pushpin
US20110042542A1 (en) * 2008-01-22 2011-02-24 Russo Kelley M Magnet-based mounting systems for frames
US8397411B2 (en) 2008-01-22 2013-03-19 Kelley M. Russo Magnet-based mounting systems for frames
US20100242230A1 (en) * 2009-03-27 2010-09-30 Saul Cohen Clothing fasteners
US8695934B2 (en) 2010-11-03 2014-04-15 Palm Coast Imports Llc Remote control unit wall docking system
WO2013068582A2 (en) * 2011-11-11 2013-05-16 Meredith Yates Magnetic attachment system
WO2013068582A3 (en) * 2011-11-11 2013-07-11 Meredith Yates Magnetic attachment system
US9328754B2 (en) 2013-01-02 2016-05-03 K & K Products, Llc Fastener
US9867754B2 (en) 2013-08-10 2018-01-16 Donald Burke Magnetic conveyance system
US20160138630A1 (en) * 2013-12-26 2016-05-19 Fujikin Incorporated Lower member fixing device and fluid control device provided with the same
US9810252B2 (en) * 2013-12-26 2017-11-07 Fujikin Incorporated Lower member fixing device and fluid control device provided with the same
US9589461B1 (en) 2014-03-29 2017-03-07 Hkc-Us, Llc Battery powered wall mounted remote control for ceiling fans and lights
US20170173920A1 (en) * 2015-08-06 2017-06-22 Hydra Heating Industries, LLC Magnetic insulation
US20170037614A1 (en) * 2015-08-06 2017-02-09 Hydra Heating Industries, LLC Magnetic clasps for insulation
US9868268B2 (en) * 2015-08-06 2018-01-16 Hydra Heating Industries, Llc. Magnetic clasps for insulation

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