Sewing – Elements – Needles
Reexamination Certificate
2003-10-06
2004-07-13
Izaguirre, Ismael (Department: 3765)
Sewing
Elements
Needles
Reexamination Certificate
active
06761121
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thread guide device for a sewing machine comprising thread transfer means for transferring an upper thread to the vicinity of a needle eye, and threading means for inserting, into the needle eye, the upper thread transferred to the vicinity of the needle eye by the thread transfer means.
2. Description of the Related Art
Conventionally, JP-A-11-179084 and JP-A-11-267383 have disclosed a sewing machine comprising an automatic thread guide device for automatically delivering an upper thread to the vicinity of a needle eye and inserting the upper thread through the needle eye, for example.
An embroidering sewing machine described in the JP-A-11-179084 comprises thread delivery means for delivering an upper thread to be overhung from the upper part of the sewing machine to the vicinity of the eye of a sewing needle, and threading means for inserting the upper thread delivered by the thread delivery means into the eye of the sewing needle. The thread delivery means includes a thread delivery arm to be rotated by half, and the thread delivery arm is provided with a thread delivery holding portion for holding the upper thread. The thread delivery arm is rotated by half so that the thread delivery holding portion is reciprocated between the standby position of the upper part of the sewing machine and the vicinity of the sewing needle.
In a thread guiding operation to be carried out until the upper thread is inserted through the eye of the sewing needle, first of all, the upper thread is held by the thread delivery holding portion moved to the standby position of the upper part of the sewing machine so that the upper thread is held. At this time, the holding force of the thread delivery holding portion is reduced such that the upper thread can easily be set.
When the upper thread is held by the thread delivery holding portion, the thread delivery arm is rotated by half and the thread delivery holding portion is moved to the sewing needle with the upper thread held therein. When the thread delivery arm is to be rotated by half, the thread delivery holding portion is set to have great holding force such that the upper thread does not slip off.
When the thread delivery holding portion is moved to such a position that the upper thread is overhung toward the eye of the sewing needle, the upper thread is inserted through the eye of the sewing needle by the threading means. At this time, the thread delivery holding portion has the holding force reduced such that the upper thread can be removed from the thread delivery holding portion after the threading.
Then, the thread delivery arm is rotated reversely so that the thread delivery holding portion is moved from the sewing needle side toward the standby position. Thus, the thread guiding operation of the upper thread is completed.
In the conventional sewing machine, however, holding force of the thread delivery holding portion cannot be changed when the thread delivery arm is rotated by half to move the thread delivery holding portion from the standby position to the vicinity of the sewing needle and to move the thread delivery holding portion from the sewing needle side to the standby position. Therefore, in the case in which the thread remains in the thread delivery holding portion after the threading, there is a possibility that the thread delivery holding portion might strongly hold and pull up a thread and remove the thread from the eye of the sewing needle and the thread cannot be consequently guided with high precision.
Moreover, when the thread delivery holding portion is moved from the standby position to the vicinity of the sewing needle, the holding force of the thread delivery holding portion is reduced. In order to guide the thread with higher precision, it is more preferable that the holding force of the thread delivery holding portion should be properly adjusted into appropriate holding force during upper thread setting or threading.
In order to guide the thread with higher precision, moreover, it is preferable that the stop position of the thread delivery holding portion in the standby position should be placed to reliably set the upper thread into the thread delivery holding portion or the stop position of the thread delivery holding portion in the vicinity of the sewing needle should be placed to carry out the threading well.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a thread guide device for a sewing machine which can carry out a thread guiding operation with higher precision.
In order to attain the object, as shown in
FIGS. 1
,
2
,
9
and
12
, for example, a first aspect of the invention is directed to a thread guide device (
1
) for a sewing machine comprising:
thread transfer means (
10
) including a thread holding portion (a thread holding portion
30
) capable of holding an upper thread and serving to hold the upper thread in a thread holding position by means of the thread holding portion and to transfer the upper thread to the vicinity of a needle eye (N);
threading means (
50
) for inserting, into the needle eye, the upper thread (A) transferred to the vicinity of the needle eye by the thread transfer means; and
holding pressure changing means (a transfer cam
19
, a holding pressure switching roller
46
, a holding pressure switching operating plate
40
, a holding pressure switching adjusting plate
42
, a holding pressure switching link
43
, a holding pressure switching plate
44
) for changing a holding pressure of the thread holding portion during transfer in which the upper thread is to be transferred from the thread holding position to the vicinity of the needle eye and during return in which the thread holding portion is to be returned to the thread holding position after the upper thread is transferred to the vicinity of the needle eye.
According to the first aspect of the invention, the thread guide device for a sewing machine comprises the holding pressure changing means. Therefore, the holding pressure of the thread holding portion can be changed during the transfer in which the upper thread is to be transferred from the thread holding position to the vicinity of the needle eye and during the return in which the upper thread is to be transferred to the vicinity of the needle eye and the thread holding portion is to be then returned to the thread holding position.
Accordingly, it is possible to set that the holding pressure of the thread holding portion is increased during the transfer and the upper thread is prevented from slipping off from the thread holding portion, and the holding pressure of the thread holding portion is reduced during the return and the thread holding portion holds the upper thread without a pull even if the upper thread remains in the thread holding portion after threading. Thus, it is possible to carry out a thread guiding operation with higher precision.
As shown in
FIG. 2
, for example, a second aspect of the invention is directed to the thread guide device for a sewing machine according to the first aspect of the invention, wherein the thread transfer means includes the thread holding portion and a thread transfer member (
20
) for reciprocating the thread holding portion between the thread holding position and the vicinity of the needle eye by a rotation, and
the holding pressure changing means includes:
a rotor (a transfer cam
19
) having two different cams (
19
b
,
19
c
) from each other and rotated relatively with respect to the thread transfer member around a rotating shaft (a shaft
18
) of the thread transfer member during the rotation of the thread transfer member;
a contact (a holding pressure switching roller
46
) provided in the thread transfer member and coming in contact with the cams of the rotor rotated relatively with respect to the thread transfer member; and
holding pressure switching means (holding pressure switching operating plate
40
, holding pressure switching adjusting plate
42
, a holding pressure switching link
43
, a holding
Izaguirre Ismael
Juki Corporation
LandOfFree
Thread guide device for sewing machine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thread guide device for sewing machine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thread guide device for sewing machine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3221062