Volume 03 Issue 09-2023
28
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
03
ISSUE
09
Pages:
28-36
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
7.063
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
ABSTRACT
The scientific research illustrates that the results of experimental studies to determine the loading of the
recommended design of the compound paws with a rubber shock absorber of the mechanism for moving materials
in a sewing machine. Based on the analysis of the obtained oscillograms and the constructed graphical dependencies,
the best parameters of the shock absorber and the compound paws of the sewing machine are recommended.
KEYWORDS
Sewing machine, movement mechanism, paw, composite, rubber, rigidity, tension, oscillation, rotation frequency,
main shaft, stitches, pitch, thickness, spring, quality, parameter.
INTRODUCTION
During the operation of the machine, the presser paws,
with the help of a spring, creates the pressure
necessary for the normal advancement of the material
[1]. The clamping force can be adjusted in the range
from 20N to 50N [2]. The value of the clamping force is
selected from the following considerations: on the one
hand, constant contact of the paws with the material
in the process of its advancement and the adhesive
force of the rail with the material must be ensured,
sufficient to overcome all other forces that impede the
advancement of the material (friction between the
layers of material, friction between the paws and
material, product inertia forces, thread tension, etc.);
on the other hand, increasing the pressure of the paws
above the allowable one can lead to damage to the
material by the needle (especially products made from
bulky yarn), to the destruction of the material or the
appearance of marks from the teeth of the rack [3].
Research Article
EXPERIMENTAL REVIEW OF THE RUBBER PAD OF THE NEW DESIGN OF
THE SEWING MACHINE
Submission Date:
September 20, 2023,
Accepted Date:
September 25, 2023,
Published Date:
September 30, 2023
Crossref doi:
https://doi.org/10.37547/ajast/Volume03Issue09-06
Bozorova Farida Maxmudgonovna
Postgraduate Student Bukhara Engineering Technological Institute, Uzbekistan
Anvar Djuraev
Doctor Of Technical Science, Professor, Tashkent Institute Of Textile Technology, Tashkent, Uzbekistan
Journal
Website:
https://theusajournals.
com/index.php/ajast
Copyright:
Original
content from this work
may be used under the
terms of the creative
commons
attributes
4.0 licence.
Volume 03 Issue 09-2023
29
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
03
ISSUE
09
Pages:
28-36
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
7.063
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
Incorrect selection of the presser paws pressure to the
material or incorrect calculation of the spring can lead
to a violation of the adhesion of the material to the
teeth of the rack and to a change in the stitch length at
different speeds of the machine. With an increase in
the speed of the main shaft, the so-called hanging
(jump) of the paws is observed. The essence of this
phenomenon is that when the gear rack is raised, the
paws receives and bounces off the material [4]. The
magnitude of the jump and its duration depend on the
characteristics of the spring and on the impact. The
presser paws, which received the initial impulse, does
not have time to return to its original position in time
before the end of the material advance. In this case,
the material remains not clamped the adhesion force
of the toothed rack with the fabric decreases; the
phenomenon is reflected in the stitch length.
To solve this problem, an experimental installation was
developed on the basis of a YAMATA sewing machine
of a conventional design with the ability to install
standard and proposed paws designs on it.
Materials and methods. The general view and block
diagram of the experimental setup are shown in fig.1.
a - General view of the experimental setup of the sewing machine with the proposed paws design.
Volume 03 Issue 09-2023
30
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
03
ISSUE
09
Pages:
28-36
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
7.063
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
b - Structural scheme of the experimental setup for measuring the load on the paws of the sewing machine.
Fig.1. General view and block scheme of the experimental setup
Sewing machine "YAMATA" 1-stitch sewing machine, 2-
sewing machine, 3-drive pulley with Hall sensor, 4-paws
bar, 5-needle position control sensor, 6-strain sensor
for thread tension control, 7-sewing needle, 8-presser
paws with a strain gauge load control on the paws, 9-
controller for changing the direction of the stitch pitch,
10-controller for the stitch pitch, 11-thread spool, 12-
tensometric amplifier UT-4 and 13-amplifier 8-ANCH.14-
Digital Converter LTR-154, 15-computer, 16- Power
supply with voltage stabilizer. The block scheme of the
experimental paws and strain gauge [5, 6] sensor is
shown in Fig.3. A distinctive feature of this measuring
system is that for the first time in practice, the load
acting on the paws is measured in the dynamics of the
sewing machine. To measure the load on the paws and
the process of interaction of the rack mechanism of the
sewing machine in the process of flashing the material
in different modes, a measuring system was developed
consisting of a paws of the proposed design with a
strain gauge installed on it, which allows measuring the
load in the operating modes of the sewing machine.
The load measuring device works as follows. On the
stand of the paws 2 of the sewing machine mounted
on the guide bushings 1, the rod 2 is fixed with the help
of a bolt 4. The design of the proposed paws is changed
in accordance with the requirements for conducting
experimental studies and the requirements for
measuring the dynamic parameters of the paws with a
rack mechanism. Paws 7 having in the lower part of
glued rubber 8 a certain thickness and properties of
rubber, which can be changed, at the request of
factorial experiments on the rubber surface from the
side of the rack mechanism, a metal plate 9 0.3 mm
thick is glued, made of sheet metal with a chromium
composition in the form of a paws. When flashing the
plastic material 9, the paws 7 interact with the rail 12
installed on the plate 13 of the sewing machine, which
ensures the normal movement of the sewn materials.
Fig.2. Scheme of the paws installed on the stand with strain gauge sensors for controlling the load on the paws
Volume 03 Issue 09-2023
31
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
03
ISSUE
09
Pages:
28-36
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
7.063
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
The paws 7 it is mounted on a specially made bracket 6, which is a dry element, both for the paws 7 and is an elastic
element for gluing strain gauges 10 from the upper and lower parts of the surface of the plate 9. The support points
of the paws 9 are moved apart more than the length of the strain gauges and are installed on the axis of rotation 11.
When loaded with a spring, the supports cause the plates to bend, which ensures changes in the resistance of the
strain gauges. Figure 3 shows a general view of composite paws with a rubber shock absorber with a load change
sensor.
Fig.3. General view of the compound paws
For a comparative analysis of the results obtained, a
sensor for controlling the rotational speed of the main
shaft of the sewing machine in the form of a Hall sensor
was also installed on the head of the sewing machine
[7, 8]. To determine the beginning of the movement of
the rack and pinion mechanism and the moment the
beginning of the firmware process, a Hall sensor is
installed, which determines the position of the needle
in relation to the paws.
The load on the paws was recorded using the installed
sensor [9, 10] on the paws.
Results of experiments and their analysis. The results
obtained were recorded on oscillograms in the form of
diagram records. The oscillograms also reflect the
frequency of signal recording with an accuracy of up to
200 MHz In the time interval of 0.001 sec, this ensured
high measurement accuracy with respect to the
measured parameter.
Figure 4 shows an approximate recording of the
oscillogram of the piercing of a material using a
standard paws design without a damping element
installed in the lower part of the paws. Also on the
oscillogram are the main shaft rotation frequency
a-general view
b-paws with load change sensor
Volume 03 Issue 09-2023
32
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
03
ISSUE
09
Pages:
28-36
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
7.063
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
curve 1, curve 2 - the position of the needle in relation
to the needle bar, Curve 3 - the torque on the main
shaft.
Fig.4. An oscillogram of the recording, changes in the pressing force of the paws to the rack mechanism of the
sewing machine installed on it with a conventional standard paws.
This record was made for a conventional paws design without damping elements. On figure 5 shows an oscillogram
recording the change in the pressing force of the paws with an elastic element installed on it under the same
conditions.
3
1
Start and end
of the rail
progress
Revolutions of
the shaft head,
the beginning of
rotation of the
needle at the top
Needle in
the down
position
Presser
foot
load in
N
2
Volume 03 Issue 09-2023
33
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
03
ISSUE
09
Pages:
28-36
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
7.063
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
Figure5. Oscillogram of the recording, changes in the pressing force of the paws to the rack mechanism of the
sewing machine with the paws installed on it with an elastic element.
A comparative analysis of the obtained research results shows that the nature of the presser paws oscillations differ
significantly from each other, both in magnitude and in the pattern of vertical movement. To study the influence of
the frequency of rotation, the main shaft of the sewing machine on its operation, in particular on the frequency,
amplitude of oscillations of the presser paws of the sewing machine, we conducted experimental studies, during
which we determined the patterns of change in the amplitude of oscillations of the paws from such parameters as the
load on the paws, rubber thickness, stitch pitch, material and speed of the main shaft of the sewing machine. On fig.
6 shows an oscillogram recording the change in the amplitude of vibrations of the paws with an increase in the speed
of rotation of the main shaft of the sewing machine.
Foot load
Start and end
of the rail
progress
3
2
1
Volume 03 Issue 09-2023
34
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
03
ISSUE
09
Pages:
28-36
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
7.063
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
1 - shaft speed 1000 rpm, point 2 - shaft speed 2000 rpm, point 3 - shaft speed 3000 rpm, point 4 shaft speed 4000
rpm.
Figure6. Oscillogram recording, changes in the amplitude of the fluctuation of the paws from the frequency of
rotation of the shaft.
The shaft speed changes from 0 to 4000 rpm for a certain period of time and oscillation amplitude. The analysis of the
obtained oscillograms shows that, the nature of the change in amplitude, as the speed of the firmware increases, the
amplitude of the fluctuations of the paws decreases. The above results were obtained after decoding the
oscillograms.
Table 1 shows the main results of the measurements carried out on the sewing machine, in which the vibration
amplitude of the paws was measured for various rubber harnesses and on the rotational speed of the main shaft of
the sewing machine [11, 12].
Table1. With a stitching step of 1 mm and with a load of 40N, the thickness of the elastic band is 2 mm
Shaft speed rpm.
1000
2000
3000
4000
Oscillation
amplitude
Without rubber
Rubber hardness
2mm
1,75
1,50
1,25
75 MP
1,75
1,0
0,80
0,5
60 MP
1,75
1,0
0,85
0,5
Presser
foot
oscillation
amplitude
Shaft speed
4000min
-1
Maxim
um
amplit
ude
values
Minimum
1000 rpm
shaft
Point 1
2
3
4
Volume 03 Issue 09-2023
35
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
03
ISSUE
09
Pages:
28-36
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
7.063
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
50 MP
1,85
1,1
0,9
0,5
40 MP
1,90
1,2
1,0
0,5
Figure7. Dependences of the change in the amplitude of oscillations of the paws on the speed of the shaft
1 row for paws without rubber, for other cases, rubber
thickness 2mm. 2- Row for rubber 40 MP. 3-row for
rubber 50MP. 4-row for rubber 60 MP, 5-row for
rubber 75 MP. Paws load 40 N.
As noted above, comparing the results, the patterns of
change in the loading of the compound presser paws
with the existing design (see Fig. 4. and Fig. 5) in
sufficient stitches, the amplitude of loading decreases.
In this case, high-frequency load fluctuations are
actually eliminated due to the rubber shock absorber.
It should be noted that when using the recommended
design of the presser paws with a rubber shock
absorber, the amplitude of plate oscillations is
significantly reduced (see Fig. 6). This leads to an
increase in the uniformity of the grinding of materials
even with a large thickness from the data in table 1. It
follows that with an increase in the frequency of
rotation of the main shaft, the amplitude of vibrations
of the paws without a rubber shock absorber
decreases from 2,0∙10^(
-
3) m until 1,25∙10^(
-3) m
under n=(1000÷4000)rpm. When using a shock
absorber made of rubber with a hardness of 75 MP, the
vibration amplitude of the lower plate decreases from
1,75∙10^(
-
3) m until 0,5∙10^(
-3) m. with an increase in
the hardness of the rubber, the amplitude of the
fluctuations of the paws decreases accordingly (see
Fig. 7). The most acceptable value of rubber hardness
for the shock absorber of the paws is the brand of
rubber 1338 (hardness 50 ÷ 60 MP), at which the
amplitude of vibrations of the lower plate of the paws
is in the aisles 0,5∙1
0^(-3) m, under n=4000rpm
CONCLUSION
On the basis of experimental studies, the patterns of
loading and vibrations of the compound paws of the
sewing machine transportation mechanism were
obtained, the impudent parameters of the paws and
the rubber shock absorber were determined, which
ensure a decrease in the amplitude of vibrations of the
paws. Based on the analysis of the obtained patterns
of fluctuations of the compound paws and the
Volume 03 Issue 09-2023
36
American Journal Of Applied Science And Technology
(ISSN
–
2771-2745)
VOLUME
03
ISSUE
09
Pages:
28-36
SJIF
I
MPACT
FACTOR
(2021:
5.
705
)
(2022:
5.
705
)
(2023:
7.063
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
constructed graphical dependencies, the rubber brand
1338 is recommended as a shock absorber of the paws
with a hardness of (50-60) MP.
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Toshkent: “Voris
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nashriyot”, 2007.
-
160 p.
3.
Mansurova D.S. Kinematics and dynamics of four-
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the working bodies of sewing machines.
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Mansurova
M.A. “Improvement of the technology
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Ponomarov S.D., Biderman V.L., Licherev K.K. and
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Baubekov S.D., Dzhuraev A. Dynamics of machines
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Nemets I. Practical application of strain gauges,
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Raevsky N.P. Sensors of mechanical parameters of
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Grigoriev E.T. Calculation and design of rubber
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