Contactless Adjustable Tensioner for Craft Spinning Apparatus

Abstract

A hobbyist spinning apparatus uses a position-adjustable permanent magnet to induce eddy currents in a rotating conductive disc. The eddy currents oppose the rotation, and the opposing (braking) force applies a consistent tension to a fiber yarn being wound onto a bobbin.

Description

FIELD

The invention relates to machines for spinning fibers into yarn. More specifically, the invention relates to an adjustable tensioner for a manually-operated spinning wheel.

BACKGROUND

A variety of machines have been conceived to assist in manufacturing yarns from bulk fiber, and for preparing those yarns for further use in making textiles by knitting, weaving and other techniques. These may be referred to generically as “spinning wheels.” Large-volume, industrial-use machines have progressed far beyond the manually-operated spinning wheels of old, but manual and modest-capacity automatic machines are still popular among hobbyists, artists, and for spinning yarn from unusual fibers of limited large-scale commercial value. Improvements to the latter type of machine may increase hobbyist's enjoyment of textile crafts and permit them to make better, more uniform yarns and fabrics.

SUMMARY

Embodiments of the invention use a non-contact mechanism to apply a controllable braking force to a rotational movement. In one aspect, a permanent magnet adjustably disposed near a rotating conductive disc applies the controllable braking force. In another aspect, a fan or turbine compresses air into a chamber from which an adjustable orifice allows it to escape. The braking force is proportional to tension on a yarn or thread being twisted and wound onto a spool. Consistent tension helps produce a uniform yarn and allows the spool to be wound smoothly for improved characteristics during subsequent use.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a partial cutaway view of a representative embodiment of the invention.

FIGS. 2-6 are photos from various vantage points of an electric spinning machine incorporating an embodiment of the invention.

DETAILED DESCRIPTION

Spinning wheels wind twisted fiber (yarn) onto a spool. To achieve uniform spooling, the tension in the yarn as it is wound should be maintained at a relatively constant level. This is typically accomplished by turning the feed mechanism or “flyer” faster than the bobbin, so that the yarn from the flyer pulls the bobbin along (thus tensioning the yarn). Or, from another perspective, the bobbin may be retarded or braked, so that tension in the yarn pulls it along.

Embodiments of the invention brake the bobbin using a non-contact means—that is, by a mechanism that does not use mechanical friction between two surfaces to provide braking. Alternate embodiments use electromagnetic fields or air pressure, as described below.

FIG. 1 shows a partial cutaway view of a representative embodiment of the invention. In a spinning machine, a frame 100 supports a flyer 110 and a bobbin 120 so that they can rotate about a common axis 130. The flyer 110 and bobbin 120 rotate in the same direction, but at slightly different speeds. The user feeds fiber 140 into the Y-shaped flyer 110 through the stem of the Y; rotation of the flyer imparts a twist to the fiber, turning it into a twisted yarn. The yarn passes through guides 152, 154, 156 before being spooled onto bobbin 120. In a preferred embodiment, guide 156 is configured to advance and retreat along an arm of the flyer so that the yarn is deposited evenly across the length of the bobbin. (See, e.g., U.S. Pat. No. 4,458,474 to inventor Robert Lee.) In other embodiments, guide 156 may be stationary (but adjustable). In such an embodiment, the user may stop the apparatus occasionally to adjust guide 156 so that yarn is wound onto a different portion of the bobbin.

To achieve uniform spooling of the fiber, steady tension should be applied to the yarn as it passes from the last guide on the flyer to the bobbin during spinning. This is traditionally accomplished through friction braking of at least one of the flyer 110 and bobbin 120. For example, a loop of string or fishing line (monofilament) may be tensioned over a groove in the bobbin or flyer to provide drag. However, this arrangement is inconvenient when changing bobbins, and at higher spinning speeds, the string experiences friction heating and can break or burn through.

An embodiment of the invention provides adjustable drag or braking on the flyer or bobbin by coupling the braked component to turn along with a conductive disc 160 (shown connected to the bobbin in this illustration), and providing a permanent magnet 170 that can be positioned at an adjustable distance from the conductive disc. (In this Figure, adjusting control 180 back and forth moves magnet 170 closer or further from conductive disc 160.) The permanent magnet induces eddy currents in the conductive disc, and these currents oppose the force rotating the bobbin. Thus, although there is no contact between the disc and the magnet, an adjustable braking force can be applied to maintain steady winding tension.

The conductive disc may be, for example, an aluminum, brass, copper or steel disc. Conductive plastics and other materials may be employed as well. Both ferromagnetic (e.g. iron or steel) and non-ferromagnetic (aluminum, brass, copper) materials may be used. The disc may take a different form, such as the “squirrel cage” rotor of an alternating-current (“AC”) electric induction motor.

It is appreciated that the conductive-disc and magnet apparatus behaves somewhat like an alternating-current motor being operated in a regeneration or braking mode. In fact, instead of a permanent magnet, an embodiment may provide one or more electromagnets (wire coils) that, when energized, induce the eddy currents that provide braking. The control system to perform commutation of the coils makes this embodiment more complex, but if controllable commutation is provided, then mechanical motion of a permanent magnet (closer or further from the disc) may be omitted: the braking force can be controlled by advancing or retarding the commutation timing instead of changing a mechanical gap. Furthermore, in an embodiment that uses controllable commutation to influence the conductive disc via suitable electromagnetic fields, the commutation could act to accelerate rather than brake the conductive disc. In effect, the conductive disc serves as an electric motor, urging the flyer or bobbin to spin faster than the other component so that the yarn is held under tension as it winds on.

In another embodiment, conductive disc 160 may be replaced by a fan or turbine, which draws atmospheric-pressure air into the machine and forces it into a closed chamber. The chamber has an adjustable pressure-relief valve, and the braking force provided by the apparatus is controlled by the spinning speed and the pressure. In this arrangement also, braking is accomplished without contact or mechanical friction.

Mechanical power to spin the bobbin and flyer can be applied to the apparatus in any conventional way. For example, a pedal-actuated belt, string, chain or gear train may be provided, or an electrical motor can be connected to the drive train.

In some embodiments, the disc-magnet distance (and corresponding braking force) may be adjusted manually by a linear or rotating threaded control. In other embodiments, the disc-magnet distance may be adjusted automatically, under the control of a servo or similar actuator. An automatic adjustment system may incorporate a measurement of present fiber tension in a feedback loop, thus allowing consistent tensioning as the diameter of the bobbin increases (because of different bobbin geometries or because the bobbin diameter increases as more yarn is wound on).

FIG. 2 is a photo of a prototype similar to the structure depicted and described in FIG. 1. This partial view shows the conductive disc, the permanent magnet and its adjustment mechanism, and a portion of a bobbin and flyer.

FIG. 3 shows another view of the same prototype. In this photo, the complete flyer and bobbin are visible, as is an electric motor for driving the spinning apparatus and an electronic speed control for the motor. In an embodiment where such electronic control is present, the commutated-electromagnet braking/tensioning arrangement could be added relatively easily. (For a fully-manual embodiment, the manually-adjustable braking from a permanent magnet may be preferred.)

FIG. 4 is another view of the conductive disc and bobbin assembly. FIG. 5 shows a front view of the prototype embodiment, and FIG. 6 shows the prototype in operation (note that the flyer is spinning so rapidly that it cannot be seen clearly in this picture. These figures show a hobbyist electric spinning machine where the flyer is driven at an adjustable speed by an electric motor to twist the fibers fed by the user and wind the resulting yarn onto the bobbin. The bobbin is pulled along by the yarn winding onto it, but is braked or retarded to tension the yarn by a non-contact mechanism such as described above. The braking force can be adjusted by moving a permanent or constant-value electromagnet near a conductive disc or rotor, or by active commutation among a plurality of electromagnets. Adjustment can be done manually, or automatically by a feedback loop that senses back EMF in the commuting electromagnets and adjusts the commutation to achieve a target tension.

The applications of the present invention have been described largely by reference to specific examples and in terms of particular allocations of functionality to certain hardware and/or software components. However, those of skill in the art will recognize that adjustable uniform tension by contactless, electromagnetic braking can also be achieved by structures that distribute the functions of the illustrated components of the invention differently than herein described. Such variations and implementations are understood to be captured according to the following claims.

Claims

1. An adjustable tensioner for a spinning wheel, comprising: a Y-shaped flyer having a yarn guide on one arm of the Y;a cylindrical bobbin with flanges at either end;a frame arranged to hold the cylindrical bobbin and the Y-shaped flyer on a common axis about which both the cylindrical bobbin and the Y-shaped flyer can rotate, the cylindrical bobbin being disposed between arms of the Y;a conductive member coupled to one of the Y-shaped flyer or the cylindrical bobbin so that the conductive member rotates with the one of the Y-shaped flyer or the cylindrical bobbin; anda permanent magnet held by the frame so that a distance between the permanent magnet and the conductive member may be adjusted.

2. The adjustable tensioner of claim 1 wherein the conductive member is a circular disc.

3. The adjustable tensioner of claim 1 wherein the conductive member comprises at least one of aluminum, copper, brass or steel.

4. The adjustable tensioner of claim 1 wherein the conductive member is a non-ferromagnetic metal.

5. The adjustable tensioner of claim 1 wherein the yarn guide on one arm of the Y is configured to automatically advance and retreat smoothly along the one arm of the Y.

6. The adjustable tensioner of claim 1 wherein the yarn guide on one arm of the Y is manually adjustable in position along the one arm of the Y.

7. A spinning wheel with an adjustable tensioner, comprising: a rotating bobbin to wind spun yarn;a feed mechanism to convey the spun yarn onto the rotating bobbin;a drive mechanism to cause the rotating bobbin and the feed mechanism to rotate; andadjustable tensioning means for altering a rotation of one of the rotating bobbin or the feed mechanism without physical contact to cause said altering.

8. The spinning wheel of claim 7 wherein the adjustable tensioning means is coupled to the rotating bobbin.

9. The spinning wheel of claim 7 wherein the adjustable tensioning means is coupled to the feed mechanism.

10. The spinning wheel of claim 9 wherein the feed mechanism is a Y-shaped flyer.

11. The spinning wheel of claim 7 wherein the adjustable tensioning means is a conductive disc adjacent a permanent magnet, said conductive disc coupled to rotate with either the rotating bobbin or the feed mechanism.

12. The spinning wheel of claim 7 wherein the adjustable tensioning means is a conductive disc adjacent an electromagnet, said conductive disc coupled to rotate with either the rotating bobbin or the feed mechanism.

13. The spinning wheel of claim 7 wherein the adjustable tensioning means is an AC induction motor rotor adjacent an electromagnet, said rotor coupled to rotate with either the rotating bobbin or the feed mechanism.

14. An electric hobbyist spinning wheel comprising: an electric motor;a Y-shaped flyer driven by the electric motor;a bobbin;a conductive disc coupled to the bobbin;a frame to hold the Y-shaped flyer and the bobbin so that they can rotate on a common axis, the bobbin positioned between arms of the Y-shaped flyer; anda magnet adjustably positioned near the conductive disc, oriented to oppose rotation of the conductive disc and the bobbin coupled thereto without physical contact between the magnet and the conductive disc.