US 2008/0000406 A1Published application

Sewing machine, bobbin and bobbin case therefor and use

OwnerPaolo COUTOinventor

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Abstract

A sewing machine which may employ a loop-making hook rotating about a vertical axis employs a one-way bobbin and bobbin case. A bobbin can have a larger flange and a smaller flange so as to fit in a suitably configured bobbin case in only one way. The bobbin may have a blind axial opening with a guide groove to fit a winder spindle in only one way so that the bobbin can only be wound in one way. Attempts at incorrect orientations cause the bobbin to protrude from the bobbin case in an obviously incorrect manner. Inadvertent efforts to wind the bobbin incorrectly are likely to be fruitless. Thus, a user can readily install the bobbin in the bobbin case with a proper orientation and with the thread correctly wound. Surprisingly, stitching problems, such as poor seams or the like, can be reduced.

Claims25

Dependent claims

A sewing machine including:

a needle mounted for reciprocal movement in opposed descending and ascending directions toward and away from a workpiece to sew the workpiece with an upper thread;
a bobbin adapted to be mounted to supply a lower thread to the needle, the bobbin comprising a hub to support wound thread and respective first and second flanges located at opposed ends of the hub to retain the thread on the hub;
a bobbin case to support the bobbin for movement beneath the workpiece, the bobbin case having a chamber to receive and seat the bobbin, wherein the bobbin and bobbin case are cooperatively configured to seat the bobbin in the bobbin case chamber in a working orientation and to prevent seating of the bobbin in a nonworking orientation;
and
a winder spindle for winding thread on to the bobbin, wherein the bobbin hub has an axial opening to receive the winder spindle in one axial direction, the hub opening being at least partially obstructed to prevent insertion of the winder spindle into the hub opening in another axial direction opposed to the one axial direction, and wherein the bobbin hub opening and the winder spindle have a cooperative locking structure to lock the bobbin to the winder spindle against rotation of the bobbin relative to the winder spindle.

2 more elements

A method of winding thread on a bobbin on a sewing machine useful for sewing a workpiece with an upper thread and a lower thread, the method employing a needle mounted for reciprocal movement in descending and ascending directions toward and away from the workpiece to sew the workpiece, an upper thread being supplied downwardly to the needle and employing a bobbin locatable beneath the needle to supply the lower thread to the needle, wherein the bobbin comprises a hub to support wound thread, respective first and second flanges located at opposed ends of the hub to retain the thread on the hub, the bobbin hub having an axial opening to receive a bobbin winder spindle in one axial direction, the hub opening being at least partially obstructed to prevent insertion of the bobbin winder spindle into the hub opening in an opposed axial direction and wherein the method comprises the steps of:

a) assembling the bobbin, when in need of thread, to the bobbin winder spindle by inserting the bobbin winder spindle into the bobbin hub in said one axial direction;
b) winding thread on to the bobbin mounted on the bobbin winder spindle;
c) in the event of an attempt to insert the bobbin winder spindle into the hub opening in said opposed axial direction, removing and reorienting the bobbin when said partial obstruction prevents the insertion attempt;
and
d) after performing step c), effecting steps a) and b).

2 more elements

Dependencies are inferred from the claim text.