Sewing – Elements – Take-ups
Reexamination Certificate
2000-10-13
2001-07-24
Izaguirre, Ismael (Department: 3765)
Sewing
Elements
Take-ups
Reexamination Certificate
active
06263812
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved sewing machine, and more particularly to an improved looper thread take-up structure of sewing machine, which is capable of very easily clearing up tangling thread.
2. Description of the Prior Art
In each sewing travel of a conventional sewing machine, the looper thread is taken up once by a take-up mechanism so as to automatically feed the thread and adjust the tightness of the looper thread.
FIGS. 1 and 2
show the take-up mechanism which includes a set of take-up cam member
61
and a thread guiding member
62
. The looper thread
63
is first passed from a thread reel (not shown) through a thread guiding eye
64
of the thread guiding member
62
and then conducted to a looper (not shown) to cooperate with the upper thread
65
passed through the stitching needle
66
for sewing. Referring to
FIG. 3
, the take-up cam member
61
is a one-piece member formed of two identically shaped cam plates
67
by burning and welding. The two cam plates
67
are spaced by a wheel rim
68
with smaller diameter to define a cam gap
69
for the thread guiding member
62
to pass there through. By means of the rotation of the take-up cam member
61
, the path of the outer rims of the cam plates
67
rotating through the thread guiding member
62
is varied in height so as to take up the stitching thread.
The earlier take-up mechanism is hidden in the base seat (not shown) of the sewing machine and fixed on a lower shaft not shown ). Once the stitching thread is broken, the thread head will be wound and tangled on the rim between the two cam plates during continuous rotation of the take-up cam member. The take-up cam member is fixed in the base seat of the sewing machine so that it is impossible to detach the take-up cam member therefrom. Under such circumstance, it is necessary to use a thin artistic knife to clear up the tangling thread in a very narrow space. This is a task. In order to solve this problem, some manufactures try to mount the take-up mechanism beside the column of the sewing machine instead (as shown in
FIGS. 1
,
2
and
3
). However, such improved structure only makes it easier to detach the take-up cam member
61
from the sewing machine. In such structure, the take-up cam plates
67
still form a one-piece member made by burning and welding. After the take-up cam member is detached, it is still very difficult to clear up the tangling thread from the very narrow wheel gap (having a width of only 2 mm ). When the thin artistic knife is extended into the very narrow wheel gap to cut off the tangling thread, it often takes place that the polished outer rim of the take-up cam member is incautiously cut by the sharp blade of the artistic knife. After the take-up cam member is mounted back onto the sewing machine for further operation, the cut formed on the polished outer rim tends to cut off the stitching thread. This leads to a more serious problem of higher ratio of broken thread. Therefore, it is not secure to use the artistic knife for clearing up the tangling thread.
Furthermore, no matter what kind of tool is used to clear up the tangling thread, it is very hard to operate the tool in the very narrow gap for removing the tangling thread. Therefore, it often takes a considerably long time (half day to one day) to clear up the tangling thread. During this period, the machine must be stopped. This greatly affects the production efficiency and results in great trouble in working. Therefore, it is necessary to provide a measure to solve the above problem.
SUMMARY OF THE INVENTION
It is therefore a primary object of the present invention to provide a looper thread take-up structure of sewing machine, which is able to easily and quickly clear up the tangling thread and can be quickly totally installed back onto the sewing machine. (An operator only needs to open the cover and unscrew the screws to quickly separate the two take-up cam plates. Accordingly, the tangling thread can be easily and quickly removed. It only takes several minutes to clear up the tangling thread and totally install the two take-up cam plates back onto the sewing machine for further sewing operation.)
It is a further object of the present invention to provide the above looper thread take-up structure of sewing machine, which has simplified structure and thus can be more easily manufactured.
It is still a further object of the present invention to provide the above looper thread take-up structure of sewing machine, which will not damage the polished outer rim of the take-up cam plates during removal of the tangling thread.
According to the above objects, the looper thread take-up structure of sewing machine of the present invention includes: a rotary shaft; a first take-up cam plate having a cam outer rim and a non-circular shaft hole detachably keyed on the rotary shaft; a second take-up cam plate having a cam outer rim and a non-circular shaft hole detachably keyed on the rotary shaft; and a spacing ring having a through hole and fitted on the rotary shaft between the first and second take-up cam plates for spacing the same, the spacing ring being detachable from the rotary shaft, whereby in case a stitching thread is accidentally tangled on the spacing ring, the first and second take-up cam plates can be separated from each other for easily clearing up the tangling thread.
In the above looper thread take-up structure of sewing machine, the spacing ring can be integrally fixed with the first take-up cam plate.
In the above looper thread take-up structure of sewing machine, the spacing ring can be integrally fixed with the second take-up cam plate.
In the above looper thread take-up structure of sewing machine, the spacing ring, the first take-up cam plate and the second take-up cam plate are independent bodies.
Alternatively, the looper thread take-up structure of sewing machine of the present invention includes: a rotary shaft; a first fixing ring detachably keyed on the rotary shaft, the first fixing ring having a key section; a first take-up cam plate having a cam outer rim and a non-circular shaft hole detachably fitted with the key section of the first fixing ring; a second take-up cam plate having a cam outer rim and a non-circular shaft hole detachably fitted with the key section of the first fixing ring; a spacing ring having a through hole and fitted on the first fixing ring between the first and second take-up cam plates for spacing the same, the spacing ring being detachable from the first fixing ring; and a second fixing ring attached the second take-up cam plate to integrally lock the first take-up cam plate, the spacing ring and the second take-up cam plate with the first fixing ring, whereby in case a stitching thread is accidentally tangled on the spacing ring, the first and second take-up cam plates can be separated from each other for easily clearing up the tangling thread.
In the above looper thread take-up structure of sewing machine, the spacing ring can be integrally fixed with the first take-up cam plate.
In the above looper thread take-up structure of sewing machine, the spacing ring can be integrally fixed with the second take-up cam plate.
In the above looper thread take-up structure of sewing machine, the spacing ring, the first take-up cam plate and the second take-up cam plate are independent bodies.
The present invention can be best understood through the following description and accompanying drawings wherein:
REFERENCES:
patent: 1947333 (1934-02-01), Clayton
patent: 2391517 (1945-12-01), Rubel
patent: 2895441 (1959-07-01), Engel et al.
patent: 4633795 (1987-01-01), Von Hagen
patent: 4917033 (1990-04-01), Satoma
Ching Chi Machine Co., Ltd.
Izaguirre Ismael
Rosenberg , Klein & Lee
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