Sewing – Elements – Bobbin winding
Reexamination Certificate
2002-05-30
2003-11-04
Izaguirre, Ismael (Department: 3654)
Sewing
Elements
Bobbin winding
Reexamination Certificate
active
06640734
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a lower thread winding device and a lower thread winding amount control device, and more particularly to a lower thread winding device suitable for supplying a lower thread to a bobbin without removing the bobbin from a horizontal holder.
2. Description of the Related Art
Conventionally, there have been proposed various lower thread winding devices capable of supplying a lower thread to a bobbin without removing the bobbin from a horizontal holder.
These conventional examples have been described in JP-A-11-47480. This publication has described that a needle bar is separated from an upper shaft by means of a needle bar separating mechanism and is held in an upper position during a thread winding operation, and at the same time, an outer holder and a bobbin are rotated through a lower shaft by means of a sewing machine motor and a thread is wound upon the bobbin, thereby carrying out lower thread winding.
[Problems that the Invention is to Solve]
In the conventional lower thread winding device, however, the needle bar separating mechanism is operated to disconnect the upper shaft from the needle bar, thereby stopping the needle bar in the upper position while the thread is wound upon the bobbin.
For this reason, even if the needle bar separating mechanism is operated to stop the needle bar, a thread take-up interlocking with the upper shaft does not stop but continues a vertical motion. For example, consequently, an upper thread is intermittently pulled and loosened by the thread take-up moving vertically while the thread pulled out of the supplied thread is wound by the lower thread winding device. In the case in which a sewing operation is automatically restarted after the lower thread winding operation is ended, therefore, a stitch formed immediately after the start of stitch formation is loosened.
Moreover, in the case in which a thread to be wound as a lower thread by the lower thread winding device is set to be an upper thread subjected to upper thread winding and the upper thread is pulled out and is wound upon the bobbin through a needle, a thread tension is changed by the thread take-up moving vertically. Therefore, there is a problem in that a great load is applied to each member of a thread winding mechanism through which the upper thread passes and thread fastening for the lower thread to be wound upon the bobbin fluctuates.
In some cases in which the upper thread acts violently and is thus entangled with a component on a thread path or slips out of the needle by the vertical motion of the thread take-up during the thread winding operation or the upper thread is to be wound upon the bobbin, moreover, the thread is pulled so that the upper thread cannot be appropriately guided to a winding position. Furthermore, the needle bar separating mechanism is incorporated around the needle bar. Therefore, there is also a problem in that a structure is complicated in the vicinity of the needle bar.
SUMMARY OF THE INVENTION
The invention has been made in consideration of these respects and has an object to stop a needle bar and a thread take-up while a lower thread is supplied to a bobbin without removing the bobbin from a horizontal holder by a lower thread winding device.
In order to achieve the object, a first aspect of the invention is directed to a lower thread winding device comprising:
a bobbin including upper and lower flanges provided on a central shaft upon which a lower thread is to be wound and both ends thereof, the upper flange having a slit opened to an outer peripheral edge;
a horizontal holder having an inner holder capable of accommodating the bobbin and an outer holder provided with a blade tip for catching a thread;
a bobbin driving member provided on an axial center of the outer holder and capable of being rotated integrally with the outer holder;
first moving means for moving the bobbin driving member to a connecting position in which the bobbin driving member and the bobbin are connected to cause the bobbin to be rotatable during an operation for winding the thread upon the bobbin and a separating position in which the bobbin driving member is disconnected from the bobbin during a sewing operation;
a thread holding member including a thread holding portion capable of holding a thread end of the thread supplied to the bobbin during the thread winding operation and a thread position regulating portion for positioning the supplied thread on a supply side by the thread holding portion during the thread winding operation to abut on the upper flange, the thread holding portion being movable to a retreat position in the vicinity of an outer peripheral surface of the outer holder and an entry position in which the supplied thread is caused to enter an inner upper part of the inner holder to be positioned above the upper flange during the thread winding operation;
second moving means for moving the thread holding portion of the thread holding member to the retreat position and the entry position;
an upper shaft clutch mechanism (
410
, a needle oscillation stepping motor
446
) provided between a drive shaft (a lower shaft
414
) to be driven by a sewing machine motor and a reciprocating member (a thread take-up crank
456
) for reciprocating a needle bar and a thread take-up in a vertical direction and capable of carrying out electrical switching into a connecting state in which the drive shaft is connected to the reciprocating member during the sewing operation and a holding state in which the connection is released and the thread take-up and the needle bar can be held in an upper position during a lower thread winding operation; and
thread winding operation control means (
193
,
193
A) for operating the first moving means and the second moving means to cause a supplied thread connected between the thread holding portion and the thread position regulating portion to enter the slit and for bringing the upper shaft clutch mechanism into a release state so that the thread can be wound upon the bobbin without vertically moving the thread take-up and the needle bar during the thread winding operation. By employing such a structure, it is possible to easily supply the bobbin with the thread to be used for embroidering without removing the bobbin from the horizontal holder. In addition, since the thread take-up is not moved vertically during the thread winding operation, the thread does not act violently and the upper thread can be prevented from being entangled or cut.
Moreover, a second aspect of the invention is directed to a lower thread winding device comprising:
a bobbin including upper and lower flanges provided on a central shaft upon which a lower thread is to be wound and both ends thereof, the upper flange having a slit opened to an outer peripheral edge;
a horizontal holder having an inner holder capable of accommodating the bobbin and an outer holder provided with a blade tip for catching a thread;
a bobbin driving member provided on an axial center of the outer holder and capable of being rotated integrally with the outer holder;
first moving means for moving the bobbin driving member to a connecting position in which the bobbin driving member and the bobbin are connected to cause the bobbin to be rotatable during an operation for winding the thread upon the bobbin and a separating position in which the bobbin driving member is disconnected from the bobbin during a sewing operation;
a thread holding member including a thread engaging portion capable of holding a thread end of an upper thread supplied to a needle during the thread winding operation and a thread position regulating portion for positioning the upper thread on a supply side by the thread engaging portion during the thread winding operation to abut on the upper flange, the thread engaging portion being movable to a retreat position in the vicinity of an outer peripheral surface of the outer holder and an entry position in which the supplied thread is caused to enter an inner upper part of the inne
Fukuba Naofumi
Hayashi Minoru
Kotaki Hiroyuki
Matsuzawa Kiyoshi
Wada Fumio
Izaguirre Ismael
Juji Corporation
Merchant & Gould P.C.
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