US3513793A - Magnetized sewing needles - Google Patents

Magnetized sewing needles Download PDF

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Publication number
US3513793A
US3513793A US758906A US3513793DA US3513793A US 3513793 A US3513793 A US 3513793A US 758906 A US758906 A US 758906A US 3513793D A US3513793D A US 3513793DA US 3513793 A US3513793 A US 3513793A
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United States
Prior art keywords
needle
magnetic
force
bar
magnetized
Prior art date
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Expired - Lifetime
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US758906A
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English (en)
Inventor
Donald R Dohr
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SINGER SPEZIALNADELFABRIK A CORP OF WEST GERMANY GmbH
SSMC Inc
Original Assignee
Singer Co
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Assigned to SINGER SPEZIALNADELFABRIK GMBH, A CORP OF WEST GERMANY reassignment SINGER SPEZIALNADELFABRIK GMBH, A CORP OF WEST GERMANY ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SINGER COMPANY, THE, A CORP OF NJ
Anticipated expiration legal-status Critical
Assigned to SSMC INC., A CORP. OF DE reassignment SSMC INC., A CORP. OF DE ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SINGER COMPANY, THE
Expired - Lifetime legal-status Critical Current

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    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05B—SEWING
    • D05B85/00—Needles
    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05D—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES D05B AND D05C, RELATING TO SEWING, EMBROIDERING AND TUFTING
    • D05D2207/00—Use of special elements
    • D05D2207/05—Magnetic devices
    • D05D2207/06—Permanent magnets
    • D—TEXTILES; PAPER
    • D05—SEWING; EMBROIDERING; TUFTING
    • D05D—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES D05B AND D05C, RELATING TO SEWING, EMBROIDERING AND TUFTING
    • D05D2209/00—Use of special materials
    • D05D2209/12—Metals or metal coatings

Definitions

  • the present invention comprises a sewing needle formed from a substantially permanent magnetic material, that is, a needle preferably composed of a hardened high carbon steel, which has aA magnetically hard state, ⁇ or in other words the steel is substantially vmore difficult to magnetize, but resists -demagnetization signiiicantly more so'than those needles formed of a soft magnetic material having a low carbonlcontent. Because of the magnetic properties of the needle, there is develv oped an attractive force between the needle and the nickel plated steel needle bar in which the needle normally is operatively disposed.
  • the predominant holdingfo'rce inv the needle-needle bar application comprises the frictional force at the needle-needle bar contact surface which is normal to the ux vector fand the magnetic attractive force.
  • the layer of gold acted as a multiplying factor of ⁇ the magnetic holding force. This unexpected phenomenon is attributed to a higher static coeicient of friction of the ducing no adverse effect on the magnetic holding force of the needle.
  • the gold plating further provides an aesthetically desirable product with a noncorrosive outer layer, as well as a more readily visible thread-receiving needle eye.
  • a further object of this invention is to provide for use in a sewing machine, a plated magnetized needle which provides a significant increase in the withdrawal force required for removal thereof from the needle bar.
  • a still yet further object of the present invention is to provide a plated magnetized sewing needle which combines highly desirable magnetic characteristics thereof with increased wear resistance and easier threading.
  • FIG. 3 illustrates an enlarged elevational view of a sewing needle constructed in accordance with the present invention, thelines indicating the magnetic iield develgold on the surface of the needlel bar compared to that y of nickel, the normal needle plating.
  • approximately 0.2 percent cobalt was used with pure gold. This composition was found to substantially double the hardness of the gold, while prooped lby the needle;
  • FIG. 4 illustrates a vertical sectional view of the needle disposed in the needle bar substantially taken onthe line 4--4 of FIG. 1, the lines indicating the magnetic field developed by the needle relative to the needle bar;
  • FIG. 5 illustrates a vertical sectional view substantially taken on the line ⁇ 5-5 of FIG. 4, the lines indicating the magnetic field developed by the'needle relative to the needle'bar; and i FIG. 6 killustrates a cross-sectional View substantially taken on the line 6,-6 of FIG. 5, thev lines indicating the vmagnetic field developed by'the needleV relativesto the adjacent needle bar surface.
  • FIG. 1 there is disclosed a sewing machine comprising the usual frame structure including a head overhanging the portion of the bed (not shown) mounting a throat plate 11 provided with the usual needle receiving throat plate hole 12.
  • a cylindrical needle bar 13 having a needle generally referred to by the numeral 14, to be described in detail hereinafter, secured at its lower end by a standard needle clamp 15, such as that forming the subject matter of a U.S. Pat. No. 2,973,733 assigned to the assignee of the present invention, to which reference may be had for a more complete description thereof.
  • the ⁇ lower end of the needle bar 13 is formed with a vertically vflat walls 18 and 19.
  • the needle clamp 15 comprises a clamping band 20 which surrounds the lower portion of the needle -bar and is formed with a bore 21 for slidingly receiving the needle-bar 13.
  • a boss portion 22 depending from the band 20 is provided with a threaded bore 23 into which is secured a thumb screw 24 whose inner end portion has a conical shape 25.
  • a screw 26 rmly secures the needle clamp band 20 to the needle bar 13 as shown in FIG. 5.
  • FIG. 2 illustrates the foregoing described needle clamp accommodating two needles 14-14 instead of the single needle disclosed in FIGS. l and 3-6, inclusive.
  • the needle clamp or for that matter any other suitable needle clamp is adapted to receive the sewing needle 14 illustrated as having a shank portion 27 formed as a slab-sided circular cylinder with the slabbed side 28 being disposed on the opposite side of the needle from the usual elongated groove 29 formed in the blade 33 of the needle, the usual thread-receiving eye 34 and needle point 35.
  • the needle properly is located in the needle-shank receiving yslot 16 with the slabbed side 28 of the needle 14 disposed adjacent the at wall 18 of the needle bar 13 as shown in FIG. 6.
  • FIGS. 4 and 5 show that the needle is located at the proper height within the needle bar 13 by means of the screw 26 which serves as an abutment stop for the needle as it is inserted upwardly into the slot 16.
  • the presently disclosed needle obviates the foregoing discussed problems found with conventional sewing needles and is unique in that it is magnetized and is formed with a thickness of gold plating over its surface. It is to be understood from the outset that it is not the purpose of this specification to discuss in detail the theory of magnetism and reference is made to a textbook such as Magnetic Circuits and Transformers prepared by the Department of electrical Engineering at M.I.T., John Wiley and Sons, Inc. for a detailed analysis and discussion thereof.
  • the needle 14 comprises a steel main body portion 30, the usual layer of nickel plating 31 found on conventional needles, and an outer layer of gold designed by the numeral 32.
  • the needle is of the hardened high carbon content variety.
  • the layer of gold can be applied to sewing needles of any variety.
  • the gold plating process consists essentially of cathodically cleaning the needle surface, activating the previous nickel plating and the gold plating.
  • the gold'plating preferably comprises an alloy (nominally v99.8 wt. percent Au, 0.2 wt. percent Co) with significantly higher inherent hardness than pure gold (140-200 Knoop compared to 70- This gold composition has excellent adhesion to the nickel substrate plate and in combination with the inherent hardness of the plate, a minimum plating thickness of approximately 20 microin'ches provides adequate Wear resistance for normal needle life.
  • the force required to withdraw the needle from the needle bar was greater than the force of gravity on the needle per se and therefore, the magnetic attractive force was suicient to hold the needle in place.
  • the use of materials other than gold to alter the attractive force Fn is within the scope of the present invention provided the coefficient of friction is such that the withdrawal force is greater than the :torce of gravity on the needle.
  • the attractive or normal force Fn is defined by the equation.
  • the needle 14 is held in the needle bar 13 primarily by a magnetic force wherein the magnetic force between the permanent magnet needle and the substantially flat wall 18 of the needle bar slot 16 holds the slab side 28 of the needle shank 27 against the needle bar wall 18, as best shown in FIG. 4.
  • the preferred approach comprisesusing a condenser d1scharge type magnet charger of the Radio Frequency Laboratory type' (Model 107A), which operates on the principleof storing energy in a capacitor over a period of time (at mostf several seconds) and then discharging the stored energy through an appropriate fixture, such as a coil, inV a relatively short time, i.e., several milliseconds.
  • a coil inV a relatively short time, i.e., several milliseconds.
  • Such units are powered from 115 v., 50-60 cycles/sec. single phase lines.
  • This method is advantageous in that the coil can be placed around a conveyor belt,VV for example, and electronically operated, thus, being very suitable for mass production.
  • the needles to be magnetized can be oriented in a controlled manner with respect to the magnetic field.
  • One approach would be to magnetize individual boxes of needle cards.
  • This property varies with the crystallographic structure of the material and its state of internal energy or stress.
  • quenching of high carbon steel, tot form martensite which makes up the major portion of the present needle composition produces the desired resistance to change of magnetic state.
  • the resultant martensitic crystal structure resists demagnetization moreso than other allotropic crystallographic structures of the needle steel.
  • Substantially permanent magnetization of high carbon steel requires a magnetizing field of substantially 6100 ampere-turns/in. (300 oersteds) for saturation.
  • Material of this type to be demagnetized must be subjected to a large externally applied field of opposite sense to lower its residual flux density, that is, the flux density remaining (Br, remanence) when the applied field is removed.
  • the measure of the permanence of the materials ferromagnetic property is the demagnetizing field necessary to reduce the magnetic flux density (Br) to zero and is defined as the coercive force.
  • a magnetic induction in gauss is induced in the needle when an external DC or pulsed magnetic field of predetermined strength is applied.
  • a residual magnetic induction (Br) or some fraction thereof, remains in the needle.
  • the magnetized needle is brought close to a separate magnetic field of opposite sense or touches an initially unmagnetized, magnetically soft or hard material such as the needle bar, then the residual mag-netic induction is further decreased until it attains an equilibrium position with the opposing field or with the magnetically soft or hard part.
  • Subsequent introduction of the needle to these same conditions Will reduce the magnetic force a minimal amount only. Therefore, for all practical purposes, it has attained an equilibrium condition. Its magnetized state will change only if brought into contact with a larger field.
  • the needles axially, i.e., with the external magnetic field applied coincident to the axis of the needle, rather than in a direction perpendicular to its axis (that is, cross magnetized) in order to obtain the greatest possible force (Fw) required for withdrawal of the needle from the needle bar.
  • Fw greatest possible force
  • thelength'of the needle shank becomes apole and there exists a very short magnet with poles of large area resulting, therefore, in a very large .reluctance path or in other words, .path or resistance, for the tiux lines, thus reducing the holding. forceof the' magnet.
  • the reluctance of the magnetic circuit may effect the value of Bg as it may contain areas where ii-ux leakage occurs thus reducing its value. This indicates, therefore, that when the needles .are -initially magnetized, the magnetically stronger needle will be the one whose direction of magnetization favors the path of least resistance (reluctance) for the magnetic circuit, namely in the axial direction.
  • the needle .with t-he lower reluctance path will have a higher Yresidual change in the cross section of the needle has on the flux density is readily apparent in this figure.
  • the needle 'shank portion 27, which has the largest cross sectional area of the needle will naturallyhave the largest number of fiux lines. Since the flux density is an intrinsicproperty of the needle material it remains constant throughout the needle per se. The flux density of the needle in air, however, is much lower than when the needle is inserted into a needle bar. This results from the fact that in the former the lines of fiux follow a path of high reluctance with a consequent decrease of magnemotive force (mmf). In the latter case the high permeability of the needle bar material results in a low reluctance path with a consequent increase in the mmf.
  • mmf magnemotive force
  • FIGS. 4, 5 and 6 illustrate a typical fiux distribution after the magnetized needle of FIG. 3 has been inserted into the needle bar slot 16.
  • the greatest concentration of liux lines appears at the interface denoted A between the slabbed side 28 of the needle 14 and the flat wall 18 of the needle bar.
  • the lines of ux predominantly take the path of lowest reluctance which is through the steel at the tip of the needle shank at the needle-needle bar interface.
  • the fiux density is highest ⁇ at and in the vicinity of the pole and decreases rapidly along the slabbed side 28 of the needle butt as it approaches the neutral magnetic axis in the shank of the needle.
  • the attractive or normal force, Fn can be calculated from the above formula or alternatively can be measured with a suitable instrument. If the formula is used the air gap area, Ag, between the needle and the needle bar surfaces must be accurately determined. Once the force Fn is known the Withdrawal force, Fw, can be determined by multiplying lt, the coefiicient of friction of the material (gold) comprising the needles outer surface relative to the surface of the needle bar, by the force Fn. It can be seen that the withdrawal force, FW, is a direct function of both the coeicient of friction, n, and the ux density, Bgz.
  • saidvneedle comprising ;a shank yportion adaptedrfto be disposed in "said slot, and being magnetized, at least the shank portion; of
  • said needle being coatedfwith a layer of' material, said magnetizred needle developing a magnetic e'ld which when the needle shank is placed in theLneedle-barfreceiving Vslot will have amagnetic'A attractive force disposed normal relative to anv adjacent "surface 'of the needle bar, said layer of material having when the needle shank is placed in the needle ibar receiving slot a coeicent of friction relative to an adjacent needle bar surface whereby there will be developed a combined magnetic-frictional retaining force requiring a force to withdraw the needle from the needle bar of a magnitude 8, 'greater than the force Aof gravity on the sewing vneedle'.
  • a :sewing needle including a shank portion and a vblade portion, said sewing needle being magnetized for developing a magnetic lield of predetermined flux density to product a resultant magnetic attractive force vector, atleast the shank portion of said needle having a layer of material disposed thereabout for substantially increas- ,ing the ⁇ :normal magnetic attractive .force developed by said. magnetizedsewing needle when brought into proximity, ⁇ with another ferromagnetic material.v

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Sewing Machines And Sewing (AREA)
US758906A 1968-09-10 1968-09-10 Magnetized sewing needles Expired - Lifetime US3513793A (en)

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US75890668A 1968-09-10 1968-09-10

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BR (1) BR6912330D0 (pt)
DE (1) DE6931782U (pt)
FR (1) FR2017699A1 (pt)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3894666A (en) * 1973-04-12 1975-07-15 Delahousse & Bruant S A Ets Upholstery needle for upholstering a stuffed article
JPS5519175A (en) * 1978-07-29 1980-02-09 Furumoto Makie Method of mounting sewinggmachine needle
US4242975A (en) * 1980-01-22 1981-01-06 The Singer Company Needle support means
EP1580309A2 (de) 2004-03-22 2005-09-28 Dürkopp Adler Aktiengesellschaft Knopfloch-Nähmaschine mit einer Knopfloch-Schneidvorrichtung

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11769A (en) * 1854-10-03 Sewing-needle
US2865376A (en) * 1956-03-27 1958-12-23 American Cyanamid Co Gold plating surgical needles

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11769A (en) * 1854-10-03 Sewing-needle
US2865376A (en) * 1956-03-27 1958-12-23 American Cyanamid Co Gold plating surgical needles

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3894666A (en) * 1973-04-12 1975-07-15 Delahousse & Bruant S A Ets Upholstery needle for upholstering a stuffed article
JPS5519175A (en) * 1978-07-29 1980-02-09 Furumoto Makie Method of mounting sewinggmachine needle
JPS5817636B2 (ja) * 1978-07-29 1983-04-08 古本 まきえ ミシン針の取り付け方法
US4242975A (en) * 1980-01-22 1981-01-06 The Singer Company Needle support means
EP1580309A2 (de) 2004-03-22 2005-09-28 Dürkopp Adler Aktiengesellschaft Knopfloch-Nähmaschine mit einer Knopfloch-Schneidvorrichtung
JP2005270654A (ja) * 2004-03-22 2005-10-06 Duerkopp Adler Ag ボタン穴裁断装置を備えたボタン穴ミシン
CN1673433B (zh) * 2004-03-22 2012-01-18 杜尔克普-阿德勒股份公司 带有钮扣孔切割装置的钮扣孔缝纫机

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FR2017699A1 (pt) 1970-05-22
BR6912330D0 (pt) 1973-01-11
DE6931782U (de) 1970-04-30

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AS Assignment

Owner name: SINGER SPEZIALNADELFABRIK GMBH, BAHNHOFSTR. 41-79,

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SINGER COMPANY, THE, A CORP OF NJ;REEL/FRAME:004647/0795

Effective date: 19861217

AS Assignment

Owner name: SSMC INC., A CORP. OF DE, CONNECTICUT

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SINGER COMPANY, THE;REEL/FRAME:005041/0077

Effective date: 19881202