Directly motor-driven structure of a sewing machine

Details Directly motor-driven structure of a sewing machine Directly motor-driven structure of a sewing machine

2003-06-25

2004-06-15

Izaguirre, Ismael (Department: 3765)

Sewing

Elements

Driving mechanisms

Reexamination Certificate

active

06748888

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to a directly motor-driven structure of a sewing machine, in which the driving motor is a high power motor with small volume and can directly drive the upper driving shaft to greatly reduce the noise and minify the vibration in operation. Moreover, the conventional fixing bracket for mounting the driving motor is omitted. Therefore, the structure and installation procedure are simplified.
2. Description of the Prior Art
FIGS. 1 and 2
show an existent sewing machine, especially an industrial sewing machine
40
. The driving motor
41
is locked under the table board
43
by a fixing bracket
42
. A belt wheel
44
is fixedly mounted on the rotary shaft of the driving motor
41
. Sequentially through a belt
45
and a belt wheel
46
, the belt wheel
44
drives the lower driving shaft
48
pivotally disposed in the lower section of the housing
47
of the sewing machine. A belt wheel
49
is fixedly mounted on the lower driving shaft
48
. Through a belt
50
and a belt wheel
51
of the upper driving shaft
52
, the belt wheel
49
drives the upper driving shaft
52
pivotally disposed in the upper section of the housing
47
of the sewing machine. Accordingly, the upper and lower driving shafts
52
,
48
synchronously respectively drive the upper and lower stitching needles (not shown) to perform sewing operation. In order to reduce the vibration generated in operation of the sewing machine, the bottom face of the entire sewing machine
40
is locked on the upper face of the table board
43
by four bolts. However, the vibration can be hardly eliminated. Therefore, the sewing machine is simply “placed” on four buffering pads
53
and can be hardly fir locked by the bolts. Such structure has some shortcomings in use as follows:
1. The transmission distance of the belt
45
is too long. In the case that the belt
45
is over-tensioned, in operation, the sewing machine will vibrate to make a noise.
2. In the case that the belt
45
is over-tensioned, when the belt
45
is revolved on the upper and lower belt wheels
46
,
44
, a noise will be produced.
3. The driving motor
41
has a large volume and heavy weight and must be locked on the table board
43
of the sewing machine by the fixing bracket
42
. Therefore, the sewing machine has a quite large volume and heavy weight and cannot be easily transferred.
4. The driving motor
41
is exposed to outer side of the sewing machine and not shaded. Therefore, the driving motor
41
tends to be contaminated by dust. Moreover, the belt
45
revolves on outer side of the sewing machine and is likely to tangle with alien article or even hurt a user's fingers.
Many kinds of improved motors with small volume and great torque have been developed. In the case that such driving motor is directly mounted on the sewing machine and the driving shaft of the motor is directly drivingly coupled with any rotary shaft of the sewing machine, the noise produced in transmission can be greatly reduced. In addition, the installation can be facilitated. However, it is necessary to consider the following problem:
Referring to
FIG. 2
, many transmission members are disposed on left side of the belt wheel
46
so that the belt wheel
46
cannot be retracted inward, that is, retracted leftward according to FIG.
2
. Besides, the upper and lower belt wheels
51
,
49
must be mounted in the housing
47
of the sewing machine
40
in alignment with each other. In the case that the driving motor
41
is mounted in lower section of the housing
47
, that is, mounted at right end of the lower driving shaft
48
, the driving motor
41
will protrude outward from right end of the housing
47
. As a result, the gravity center of the driving motor will suspend outside the housing
47
. Therefore, after the driving motor is added to the sewing machine, the gravity center of the entire sewing machine will moved rightward. Accordingly, when operating, the sewing machine is likely to vibrate and produce noise.
SUMMARY OF THE INVENTION
It is therefore a primary object of the present invention to provide a directly motor-driven structure of a sewing machine. The sewing machine includes: an upper driving shaft mounted on upper side of a housing of the sewing machine for driving an upper stitching needle; a lower driving shaft mounted on lower side of the housing for driving a lower stitching needle; and a driving motor for driving the upper and lower driving shafts, making the upper and lower stitching needles perform sewing operation. The directly motor-driven structure includes: a middle rotary shaft pivotally mounted in a middle section of the housing between the upper and lower driving shafts; a first transmission mechanism connected between the lower driving shaft and the middle rotary shaft to drivingly rotatably connect the lower driving shaft with the middle rotary shaft, the first transmission mechanism being spaced from the lower stitching needle by a first length; and a second transmission mechanism connected between the upper driving shaft and the middle rotary shaft to drivingly rotatably connect the upper driving shaft with the middle rotary shaft. The second transmission mechanism is spaced from the upper stitching needle by a second length. The second length is smaller than the first length, whereby the sewing machine is formed with a recessed installation space adjacent to the second transmission mechanism. The driving motor is installed in the recessed installation space and directly fixedly connected with the upper driving shaft so as to reduce the noise in transmission. The total volume of the sewing machine is reduced. Moreover, the conventional fixing bracket for mounting the driving motor under the table board is omitted. Therefore, the structure and installation procedure are simplified.
The present invention can be best understood through the following description and accompanying drawings wherein:


REFERENCES:
patent: 1130309 (1915-03-01), Mace
patent: 2161142 (1939-06-01), De Voe
patent: 2322397 (1943-09-01), Smith
patent: 4714037 (1987-12-01), Johnson et al.
patent: 5125354 (1992-06-01), Hayashi et al.
patent: 40269997 (1992-09-01), None

Affiliated with

Also associated with

Rating

Directly motor-driven structure of a 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 Directly motor-driven structure of a sewing machine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Directly motor-driven structure of a sewing machine will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3320596