Bobbin assembly with backlash preventing structure

Information

  • Patent Grant
  • 6585181
  • Patent Number
    6,585,181
  • Date Filed
    Tuesday, April 3, 2001
    23 years ago
  • Date Issued
    Tuesday, July 1, 2003
    21 years ago
  • Inventors
  • Examiners
    • Matecki; Kathy
    • Pham; Minh-Chau
    Agents
    • Wood, Phillips, Katz, Clark & Mortimer
Abstract
The combination of a bobbin assembly and a support for the bobbin assembly. The bobbin assembly has a core around which a supply of thread can be wrapped and having a rotational axis, a first flange having first and second oppositely facing surfaces with the first surface bounding a storage space for thread wrapped around the core, and a magnetic element. The support has a third surface with a first metal material facing the second surface with the bobbin assembly operatively connected to the support and sufficiently close to the magnetic element so that a magnetic field is generated between the magnetic element and first metal material that tends to resists movement of the bobbin assembly relative to the support around the rotational axis of the core.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




This invention relates to bobbin assemblies for supplies of thread as used on different sewing machines and, more particularly, to a bobbin assembly having structure which cooperates with a support for the bobbin assembly to prevent backlash of thread due to overrunning.




2. Background Art




Bobbins are used for thread supplies on a wide range of sewing equipment. Typically, the bobbin has a core with a rotational axis and axially spaced flanges which bound a storage space for thread wrapped around the core. The bobbin is mounted on a support for rotation around the core axis. By rotating the bobbin, thread wrapped around the core is controllably paid out.




Ideally, the bobbin is guidingly rotated during operation without any significant resistance as might cause uneven line distribution or, in a worse case, jamming of the bobbin. While smooth rotation of the bobbin is desirable during sewing operations, the unimpeded rotation of the bobbin potentially causes thread backlash. Ideally, as the machinery is stopped, the bobbin rotation simultaneously ceases. However, due to the free rotation of the bobbin, the momentum of the rotating bobbin causes it to continue to rotate which could produce a backlash in the thread. This may require that the machinery be shut down to allow the backlash to be eliminated. Severely backlashed thread may have to be cut. Potentially, there is a significant loss of operating time, as well as the inconvenience of having to manually remedy the backlash situation. Severe backlashing may require replacement of the bobbin with a bobbin having a new supply of thread. Consequently, significant amounts of thread may be wasted.




Potentially of greater significance is the fact that a slackened thread resulting from overrunning of the bobbin may cause at least temporary defective stitching after the equipment is re-started. This may lead to defective product that may have to either be re-stitched or destroyed.




To address this problem, it is known to install disk-like spring elements on a case which confines the bobbin into its operative position. These springs have deflectable arms which produce a frictional bias force on the bobbin. This force is preferably controlled so that it does not significantly impede rotation of the bobbin during a sewing operation yet produces enough resistance that the bobbin will not continue to rotate once the equipment is stopped, as might cause thread backlash.




SUMMARY OF THE INVENTION




In one form, the invention is directed to the combination of a bobbin assembly and a support for the bobbin assembly. The bobbin assembly has a core around which a supply of thread can be wrapped and having a rotational axis, a first flange having first and second oppositely facing surfaces with the first surface bounding a storage space for thread wrapped around the core, and a magnetic element. The support has a third surface with a first metal material facing the second surface with the bobbin assembly operatively connected to the support and sufficiently close to the magnetic element so that a magnetic field is created between the magnetic element and first metal material that tends to resist movement of the bobbin assembly relative to the support around the rotational axis of the core.




In one form, the first metal material is attracted to the magnetic element with a force that tends to resist movement of the bobbin assembly relative to the support means around the rotational axis of the core.




In one form, the magnetic element is a first discrete element on the first flange.




In one form, the first flange is made from a non-metallic material to which the first discrete element is attached.




The non-metallic material may be a moldable material, such as plastic.




In one form, the third surface is defined by a second material that is different than the first metal material.




A second magnetic element may additionally be provided on the first flange.




The invention is also directed to the combination of a bobbin assembly and a support for the bobbin assembly. The bobbin assembly has a core around which a supply of thread can be wrapped and having a rotational axis, and a first flange having first and second oppositely facing surfaces, with the first surface bounding a storage space for thread wrapped around the core. The first flange is made of a first metal material. The support has a third surface facing the second surface with the bobbin assembly operatively connected to the support and a magnetic element that is one of at or adjacent to the third surface so that a magnetic field is created between the magnetic element and first metal material that tends to resist movement of the bobbin assembly relative to the support around the rotational axis of the core.




The first metal material defines at least a part of the second surface.




The first metal material may be embedded in the first flange.




In one form, the first metal material is attracted to the magnetic element with a force that tends to resist movement of the bobbin assembly relative to the support around the rotational axis of the core.




The magnetic element may be a discrete element embedded in the support.




The invention is also directed to the combination of a bobbin assembly and a support for the bobbin assembly. The bobbin assembly has a core around which a supply of thread can be wrapped and having a central axis, a first flange having first and second oppositely facing surfaces with the first surface bounding a storage space with thread wrapped around the core, and a first magnetic element. A support has a third surface facing the second surface with the bobbin assembly operatively connected to the support and a second magnetic element that is one of at or adjacent to the third surface. The first and second magnetic elements interact to produce a force that tends to resist movement of the bobbin assembly relative to the support around the rotational axis of the core.




The force produced by the interaction of the first and second magnetic elements may be either an attractive force or a repulsive force.




The combination may further include a third magnetic element on the bobbin assembly that interacts with the second magnetic element to produce a force that tends to resist movement of the bobbin assembly relative to the support around the rotational axis of the core.




A third magnetic element may be provided on the support to interact with the first magnetic element to produce a force that tends to resist movement of the bobbin assembly relative to the support around the rotational axis of the core.




The third magnetic element may be embedded in moldable material.




The first magnetic element may be embedded in the first flange.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a partially schematic, exploded, partial cross-sectional view of a bobbin assembly with projections on spaced flanges thereon, according to the present invention, and with the bobbin assembly operatively connected to a bobbin basket, a bobbin case, and a loop taker;





FIG. 2

is a side elevation view of the bobbin assembly in

FIG. 1

with a supply of thread wrapped therearound;





FIG. 3

is a perspective view of a bobbin assembly with an alternative form of projection on one flange thereof, according to the present invention;





FIG. 4

is a perspective view of a flange on the inventive bobbin assembly with another form of projection thereon;





FIG. 5

is a side elevation view of the flange in

FIG. 4

;





FIG. 6

is a view as in

FIG. 4

of a still further form of projection which is embedded in the flange, according to the invention;





FIG. 7

is a cross-sectional view of the flange taken along line


7





7


of

FIG. 6

;





FIG. 8

is a view as in

FIG. 4

of a further modified form of projection, according to the present invention;





FIG. 9

is a view as in

FIG. 8

of a further modified form of projection, according to the present invention;





FIG. 10

is a view as in

FIG. 9

with a still further form of projection, according to the present invention;





FIG. 11

is a cross-sectional view of the flange taken along line


11





11


of

FIG. 10

;





FIG. 12

is a view as in

FIG. 10

of a still further modified form of projection, according to the present invention;





FIG. 13

is a side elevation view of the flange in

FIG. 12

;





FIG. 14

is a view as in

FIG. 12

of a still further modified form of projection, according to the invention;





FIG. 15

is a view as in

FIG. 14

of a still further modified form of projection, according to the present invention;





FIG. 16

is a side elevation view of the flange of

FIG. 15

;





FIG. 17

is a partially schematic, partial cross-sectional view of a modified form of bobbin assembly, according to the present invention, operatively connected to a bobbin basket and bobbin case as in FIG.


1


and utilizing magnetic elements;





FIG. 18

is a perspective view of one of the flanges on a bobbin basket as in FIG.


17


and showing magnetic elements thereon, according to the present invention;





FIG. 19

is a fragmentary, cross-sectional view of a modified form of bobbin assembly and support, according to the present invention, and showing the cooperation between one of the bobbin basket flanges and a magnetic element on the bobbin case;





FIG. 20

is a view as in

FIG. 19

of a further modified form of the invention wherein the bobbin basket is made from a plastic material having a metallic element attached thereto;





FIG. 21

is a fragmentary, partial cross-sectional view of a bobbin assembly as in FIG.


17


and operatively connected to the bobbin case according to the invention;





FIG. 22

is a view as in

FIG. 21

of a modified form of the invention wherein the bobbin case of

FIG. 21

is made from a plastic material and has metallic elements embedded therein;





FIG. 23

is a view as in

FIG. 19

of a further modified form of the invention with a magnetic element fully embedded in the bobbin case;





FIG. 24

is a view as in

FIG. 20

with the metallic element on the bobbin assembly embedded so as to be fully surrounded by material defining the bobbin basket;





FIG. 25

is a view as in

FIG. 24

showing magnetic elements on the bobbin assembly/bobbin case, according to the invention, which cooperate to retard relative rotational movement between the bobbin assembly and bobbin case;





FIG. 26

is an end view of magnetic elements on the bobbin assembly and bobbin case according to the present invention;





FIG. 27

is a view as in

FIG. 26

with a modified form of magnetic elements, according to the invention; and





FIG. 28

is a fragmentary, elevation view showing a magnetic element, attached to a surface as by adhesive, according to the invention.











DETAILED DESCRIPTION OF THE DRAWINGS




In

FIG. 1

, a sewing machine assembly is shown at


10


and consists of a bobbin basket


12


and a cooperating bobbin case


14


which are matable to produce a compartment


16


for one form of bobbin assembly


18


, according to the present invention. The bobbin basket


12


has a cup-shaped body


20


with a post


22


projecting upwardly therefrom for passage through a hollow sleeve


23


depending from a top wall


24


and a contiguous opening


25


through the top wall


24


of the cup-shaped bobbin case


14


. The post


22


is directed through the sleeve


23


fully so as to be exposed at the top of the wall


24


. A latch assembly


30


is operable to engage a notch


32


in the post


22


to prevent separation of the mated bobbin case


14


and bobbin basket


12


, as with the bobbin assembly


18


operatively connected thereto and captive therebetween. A conventional loop taker


34


is operably associated with the joined bobbin basket


12


and bobbin case


14


and is useable in conventional manner, as well known to those skilled in this art.




The bobbin assembly


18


, as seen also in

FIG. 2

, consists of a cylindrical core


36


around which a supply of thread


38


is wrapped. The hollow sleeve


23


extends through a bore


37


in the core


36


so that the bobbin assembly


18


is rotatable guidingly around the sleeve


23


about an axis


40


relative to the bobbin basket


12


and bobbin case


14


.




The bobbin assembly


18


further consists of disk-shaped, first and second flanges


42


,


44


, at axial ends of the core


36


and cooperatively bounding a thread storage space


46


.




The bobbin assembly construction may vary considerably in terms of its shape and composition. As one example, the entire bobbin assembly


18


can be molded or otherwise formed from one piece of plastic. Alternatively, the bobbin assembly


18


can be made from metal. As a still further alternative, the flanges


42


,


44


can be made from a different material than the core


36


. It is known, for example, to make the flanges


42


,


44


from a paper-type material.




The bobbin basket


12


and bobbin case


14


cooperatively define a support for the bobbin assembly


18


. The flange


42


has a first surface


48


that bounds the storage space


46


, and an oppositely facing second surface


50


. With the bobbin assembly


18


operatively connected as in

FIG. 1

, the first surface


48


faces a third surface


52


on the bobbin case/support


14


.




The flange


44


has a surface


54


bounding the storage space


46


and an oppositely facing surface


56


which is in proximity to an oppositely facing surface


58


on the bobbin basket/support


12


with the bobbin assembly


18


operatively connected as in FIG.


1


and the bobbin basket


12


and bobbin case


14


joined to each other.




According to the invention, one or both of the surfaces


50


,


56


has at least one projection


60


, and in this case a plurality of projections


60


. The projections


60


shown are fiber-like projections


60


which are either integrally formed with the flanges


42


,


44


or separately adhered thereto, as by an adhesive. The fiber-like projections


60


may be integrally formed in a molding operation or attached as part of a sheet, or individually, as by an adhesive. The fiber-like projections


60


may be made from plastic, metal, or virtually any other type of material having sufficient integrity to remain reasonably intact after use in this environment, as described below. The projections


60


might be made from metal, or other material that is embedded in the flanges


42


,


44


.




The projections


60


on the first flange


42


bear against the bobbin case surface


52


, whereas the projections


60


on the flange


44


bear against the surface


58


on the bobbin basket


12


, with the bobbin assembly


18


operatively connected as in FIG.


1


and the bobbin basket


12


and bobbin case


24


joined to each other. The projections


60


are dimensioned so that, while they bear against the surfaces


52


,


58


as the bobbin assembly


18


is rotated around the axis


40


in operation, they do not significantly impede the rotation of the bobbin assembly


18


relative to the bobbin basket


12


and bobbin case


14


. At the same time, the projections


60


produce enough resistance to prevent overrunning of the bobbin assembly


18


, once the machinery is stopped and thread is no longer being drawn off of the bobbin assembly


18


as might otherwise produce backlash. The projections


60


can be made of a dimension to either be maintained in their straight configuration or bent partially towards the surface from which they project, as shown for the projections


60


acting against the bobbin case surface


52


in FIG.


1


. The projections


60


could also be configured to be bent against the surface from which they project.




In

FIG. 3

, a bobbin assembly


70


is shown with the same general construction as the bobbin assembly


18


and has a flange


72


with a surface


74


and a plurality of cantilevered, post-like projections


76


from the surface


74


, at spaced locations, to bear against a facing support surface, such as those


52


,


58


, previously described. As in all embodiments described herein, the bobbin assembly


70


may be made from virtually any material, with the projections


76


likewise being made from any material that facilitates sliding movement against either of the support surfaces


52


,


58


and which produces enough resistance to avoid overrunning. The projections


76


may be relatively rigid or somewhat flexible so as to be bendable during operation.




In

FIGS. 4 and 5

, an alternative form of projection is shown on an exemplary flange


78


that may be useable on a bobbin basket to cooperative with a support surface. The flange


78


has a surface


80


which supports a layer


82


having projections


84


thereon. The layer


82


may be maintained on the flange


78


by an adhesive


86


. The projections


84


may be rigid or in the form of fibers. As just one example, the layer


82


with the projections


84


thereon may be a component typically used in hook-and-loop type fasteners systems. That is, the projections


84


may be part of a hook-type element or loop-type element that is part of such a fastener system.




In

FIGS. 6 and 7

, a flange


90


is shown with ridge-like projections


92


that are embedded in the flange


90


. As just one example, the material defining the flange


90


may be plastic, which is molded around each projection


92


. Alternatively, the projections


92


may be frictionally held in place or held in place by an adhesive. The projections


92


shown have convex outer surfaces


94


which bear on a cooperating support surface. The number, shape and configuration of the projections


92


in

FIGS. 6 and 7

may vary from that shown.




In

FIGS. 8 and 9

, separate flanges


100


,


102


are shown with integrally formed ridge-like projections


104


,


106


from surfaces


108


,


110


on the flanges


100


,


102


. The projections


104


have a curved shape, with the projection


106


having a continuous spiral shape. The projections


104


,


106


might be separately formed and attached to the flanges


100


,


102


.




In

FIGS. 10 and 11

, a flange


116


is shown with projections


118


defined on a surface


120


thereof. In this case, the projections are formed by roughening the surface


120


by any means known to those skilled in this art.




In

FIG. 14

, a flange


130


is shown with a surface


132


having another form of projection, including long and short, generally straight, ridge-like projections,


134


,


136


. As in all embodiments, the projections


134


,


136


may be integrally formed, molded in place, or attached as by an adhesive.




In

FIGS. 12 and 13

, a flange


140


is shown with projections


142


in the form of spring-type elements with offset free ends


144


. The free ends


144


are biased upwardly and are urged under a captive force slightly downwardly towards a flange surface


146


from which they project with the bobbin assembly on which the flange


140


is provided operatively connected to a support therefor.




One or both of the projections


142


shown may be made from a shape-retentive material, such as thin metal, which can be placed and maintained in a plurality of different configurations, as shown for example in dotted lines in

FIG. 13

, to thereby vary the resistive force.




In

FIGS. 15 and 16

, a flange


152


is shown with a pair of projections


154


,


156


from a surface


158


. The projection


154


has an end


160


secured to the surface


158


, as by a fastener


162


, and a free end


164


that is bent upwardly, and preferably reconfigurable as the projections


142


in

FIGS. 12 and 13

.




The projection


156


has a fastener


166


which maintains a central portion thereof attached to the surface


158


, and spaced free ends


168


,


170


, corresponding to those


144


previously described, and projecting upwardly from the surface


158


to be biased against a cooperating support surface. The free ends may be reconfigurable and made from a shape-retentive material that can be reconfigured, or a spring-type material which tends towards a single configuration.




In all the embodiments shown, the bobbin assemblies, according to the present invention, can be operatively connected so that the projections on the flange surfaces thereon abut to a surface on a cooperating support to guide, yet not significantly inhibit, rotation of the bobbin relative to the support. The projections shown are but exemplary of the many different types of projections contemplated by the invention. It is desirable that, regardless of the shape of the projection, the projection(s) occupy an area on its associated flange surface that is less than the area of that flange surface.




In

FIGS. 17 and 18

, a further modified form of sewing machine assembly, according to the present invention, is shown at


200


. The sewing machine assembly


200


consists of a bobbin assembly


202


, having a construction corresponding to that of the bobbin assembly


18


, previously described, and including a cylindrical core


204


having a rotational axis


206


, and axially spaced flanges


208


,


210


with axially facing surfaces


212


,


214


cooperatively bounding a thread storage space


216


. Flange surfaces


218


,


220


face axially oppositely to the surfaces


212


,


214


and are situated in adjacent, facing relationship with support surfaces


222


,


224


on the aforementioned bobbin basket


12


and bobbin case


14


with the bobbin assembly


202


operatively connected to the bobbin basket


12


and bobbin case


14


.




Discrete magnetic elements


226


,


228


are embedded in the flange


208


at diametrically opposite locations. In this embodiment, the magnetic elements


226


,


228


are embedded in the flange


208


so as to be flush with the surface


218


. The magnetic elements


226


,


228


generate a magnetic field in the space


230


between the facing bobbin assembly and bobbin basket surfaces


218


,


222


.




In this embodiment, the bobbin basket


12


is shown made entirely from a metal material which may or may not be attracted to the magnetic elements


226


,


228


. The resulting magnetic field produces a force that tends to resist movement of the bobbin assembly


202


around the axis


206


relative to the bobbin basket


12


. The system is designed so that there is a slight resistance to rotation that reduces the likelihood of thread backlash which does not significantly impede the free relative rotation between the bobbin assembly


202


and the bobbin basket


12


. At the same time the system can be designed to produce a controlled resistance to rotation of the bobbin assembly


202


to thereby selectively control thread tension.




A like arrangement of magnetic elements


232


,


234


may be provided on the flange


210


to cooperate with the metallic material on the bobbin case


14


. The magnetic elements


232


,


234


are likewise shown to be embedded in the bobbin assembly


202


so as to be flush with the flange surface


220


. This embedding is facilitated by forming the bobbin assembly


202


from a moldable material that can be formed around the magnetic elements


226


,


228


,


232


and


234


in a well known manner. The bobbin assembly


202


may be made from plastic or any other moldable material. Alternatively, the magnetic elements


226


,


228


,


232


,


234


could be mounted in a pre-formed receptacle in a non-moldable material, or surface mounted, as hereafter described.




The metallic material defining the bobbin basket


12


and bobbin case


14


may either be attractive or unattractive to the magnetic elements


226


,


228


,


232


and


234


. In the latter case, the entire bobbin basket


12


and bobbin case may be made from the metallic material. This allows a magnetic field to be generated in the spaces between the bobbin assembly


202


and the bobbin basket


12


and the bobbin assembly


202


and bobbin case


14


.




In the event that the metal material on the bobbin basket and the bobbin case


14


is attractive to the magnetic elements


226


,


228


,


232


and


234


, it is desirable, though not required, that the metal material on the bobbin basket


12


and bobbin case


14


be provided as one or more discrete elements attached thereto.




In

FIG. 18

, a modification to the flanges


208


,


210


is shown wherein the magnetic elements


226


,


228


,


232


and


234


project outwardly from the associated surfaces


218


,


220


as opposed to being flush therewith as in FIG.


17


.




In

FIG. 19

, the bobbin basket


12


is shown to be made from a plastic material. A magnetic element


236


, corresponding to the magnetic elements


226


,


228


, is embedded in the bobbin basket


12


so as to protrude outwardly from the surface


222


into the space


230


. In this embodiment, the flange


208


on the bobbin assembly


202


is shown to be made entirely of metal to cooperate in the manner previously described. That is, the magnetic element


236


is designed to generate a magnetic field within the space


230


without attracting the flange


208


or may attract the flange


208


with a force calculated to generate a retarding force without significant impedance to rotational movement.




In

FIG. 20

, a modified flange, corresponding to the flange


208


of

FIG. 19

, is shown at


237


. Rather than making the entire flange


237


from metal, the flange


237


is made from plastic, or other material, and has embedded therein a metallic element


238


which preferably radially coincides with the location of the magnetic element


236


to produce the retarding force, as previously described. One or more of the metallic elements


238


may be embedded in the flange


237


with a combined circumferential extent partially or fully around the axis


206


. Discrete metallic elements


238


may be provided with a circumferential extent that is dictated by the degree of retardation of the rotational movement of the bobbin assembly


202


that is desired.




It should be understood that while variations are described with respect to the cooperation between the bobbin assembly


202


and the bobbin basket


12


, the same construction can be used between the flange


210


and the bobbin case


14


. As just one example, as shown in

FIG. 21

, the flange


210


is shown with the magnetic elements


232


,


234


cooperating with a metallic surface


224


on the bobbin case


14


.




In

FIG. 22

, the system in

FIG. 21

is modified by making the bobbin case


14


from plastic, or other non-metallic material, in which one or more discrete metallic elements


240


are embedded in radial overlap with the magnetic elements


232


,


234


. In this embodiment, the metallic elements


240


are fully embedded so that they are not directly exposed at the support surface


224


on the bobbin case


14


.




In

FIG. 23

, a variation from the structure in

FIG. 19

is shown wherein the magnetic element


236


is embedded and fully surrounded, as by a plastic material, so as not to be directly exposed at the surface


222


.




In

FIG. 24

, variation of the structure in

FIG. 20

is shown wherein a metallic element


238


is embedded in the flange


208


and fully surrounded by the material defining the flange


208


, so as not to be directly exposed at the flange surface


218


.




In

FIGS. 25 and 26

, a further modification, according to the present invention, as shown wherein cooperating magnetic elements


244


,


246


are embedded in the bobbin basket


12


and bobbin case


14


, shown in this case to be plastic, but not limited to this composition. The magnetic elements


244


,


246


may be such as either to attract or repel each other. This mutual attraction or repulsion produces an impedance to the free relative rotation between the bobbin basket


12


and bobbin case


14


.




In

FIG. 26

, the magnetic elements


244


,


246


are shown in the form of discrete, arcuate elements which are circumferentially spaced around the axis


206


.The shape and circumferential extent of the magnetic elements


244


,


246


is dictated by the desired retarding force.




As another example, as shown in

FIG. 27

, corresponding magnetic elements


244


′,


246


′ have a circular cross section, with the diameter, number and location being dictated by the desired retarding force.




As an alternative to embedding the magnetic elements, each of the magnetic elements described above, and shown generically at


248


in

FIG. 28

, can be attached to an associated support or flange


250


on an external surface


252


thereof, as by the use of an adhesive


254


.




All of the above designs lend themselves to controlling bobbin assembly rotation to avoid thread backlash and/or control thread tension.




The foregoing disclosure of specific embodiments is intended to be illustrative of the broad concepts comprehended by the invention.



Claims
  • 1. In combination:a) a bobbin assembly comprising: i) a core around which a supply of thread can be wrapped, the core having a rotational axis; ii) a first flange having first and second oppositely facing surfaces, the first surface bounding a storage space for thread wrapped around the core; and iii) a magnetic element; b) a support for the bobbin assembly, said support comprising: i) a third surface comprising a first metal material facing the second surface with the bobbin assembly operatively connected to the support and sufficiently close to the magnetic element so that a magnetic field is generated between the magnetic element and first metal material so as to generate a force that resists movement of the bobbin assembly relative to the support around the rotational axis of the core to a degree that the force does not significantly impede free relative rotation between the bobbin assembly and support but resists rotation to reduce the likelihood of thread backlash; and c) a loop taker for drawing thread off of the bobbin assembly by causing rotation of the bobbin assembly.
  • 2. The combination according to claim 1 wherein the first metal material is attracted to the magnetic element.
  • 3. The combination according to claim 1 wherein the magnetic element comprises a first discrete element on the first flange extending through less than 360° around the rotational axis.
  • 4. The combination according to claim 3 wherein the first flange is made from a non-metallic material to which the first discrete element is attached.
  • 5. The combination according to claim 4 wherein the non-metallic material comprises a moldable material.
  • 6. The combination according to claim 5 wherein the non-metallic material comprises plastic.
  • 7. The combination according to claim 1 wherein the third surface comprises a second material that is different than the first metal material.
  • 8. The combination according to claim 1 further comprising a second magnetic element on the first flange.
  • 9. In combination:a) a bobbin assembly comprising: i) a core around which a supply of thread can be wrapped, the core having a rotational axis; ii) a first flange having first and second oppositely facing surfaces, the first surface bounding a storage space for thread wrapped around the core, wherein the first flange comprises a first metal material; b) a support for the bobbin assembly, said support comprising: i) a third surface facing and adjacent the second surface with the bobbin assembly operatively connected to the support; and ii) a magnetic element that is one of at or adjacent to the third surface so that a magnetic field is generated between the magnetic element and first metal material so as to generate a force that resists movement of the bobbin assembly relative to the support around the rotational axis of the core to a degree that the force does not significantly impede free relative rotation between the bobbin assembly and support but resists rotation to reduce the likelihood of thread backlash; and c) a loop taker for drawing thread off of the bobbin assembly by causing rotation of the bobbin assembly.
  • 10. The combination according to claim 9 wherein the first metal material defines at least a part of the second surface.
  • 11. The combination according to claim 9 wherein the first metal material is embedded in the first flange.
  • 12. The combination according to claim 9 wherein the first metal material is attracted to the magnetic element.
  • 13. The combination according to claim 9 wherein the magnetic element comprises a discrete element embedded in the support.
  • 14. In combination:a) a bobbin assembly comprising: i) a core around which a supply of thread can be wrapped, the core having a rotational axis; ii) a first flange having first and second oppositely facing surfaces, the first surface bounding a storage space for thread wrapped around the core; and iii) a first magnetic element; b) a support for the bobbin assembly, said support comprising: i) a third surface facing the second surface with the bobbin assembly operatively connected to the support; and ii) a second magnetic element that is one of at or adjacent to the third surface, the first and second magnetic elements interacting to produce a force that resists movement of the bobbin assembly relative to the support around the rotational axis of the core to a degree that the force does not significantly impede free relative rotation between the bobbin assembly and support but resists rotation to reduce the likelihood of thread backlash; and c) a loop taker for drawing thread off of the bobbin assembly by causing rotation of the bobbin assembly.
  • 15. The combination according to claim 14 wherein the force produced by the interaction of the first and second magnetic elements is an attractive force.
  • 16. The combination according to claim 14 wherein the force produced by the interaction of the first and second magnetic elements is a repulsive force.
  • 17. The combination according to claim 14 further comprising a third magnetic element on the bobbin assembly that interacts with the second magnetic element to produce a force that resists movement of the bobbin assembly relative to the support around the rotational axis of the core.
  • 18. The combination according to claim 17 wherein the third magnetic element is embedded in a moldable material.
  • 19. The combination according to claim 14 further comprising a third magnetic element on the support that interacts with the first magnetic element to produce a force that resists movement of the bobbin assembly relative to the support around the rotational axis of the core.
  • 20. The combination according to claim 14 wherein the first magnetic element is embedded in the first flange.
CROSS REFERENCE

This application is a continuation-in-part of application Ser. No. 09/794,702, filed Feb. 27, 2001, entitled “Bobbin Assembly With Backlash Preventing Structure”.

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2555658 Ritter Jun 1951 A
2561155 Thomas, Jr. et al. Jul 1951 A
2784690 Brandt Mar 1957 A
3716202 Thomas Feb 1973 A
4328932 Nelson May 1982 A
4434951 Nakajima Mar 1984 A
4830308 Puryear May 1989 A
4940194 Young Jul 1990 A
5018465 Hager et al. May 1991 A
5108042 Puryear et al. Apr 1992 A
5301899 Sato Apr 1994 A
5636804 Jeung Jun 1997 A
5842431 Wu Dec 1998 A
6257512 Schoeck et al. Jul 2001 B1
Continuation in Parts (1)
Number Date Country
Parent 09/794702 Feb 2001 US
Child 09/825417 US