Volume 04 Issue 04-2022
58
The American Journal of Engineering and Technology
(ISSN
–
2689-0984)
VOLUME
04
I
SSUE
04
Pages:
58-67
SJIF
I
MPACT
FACTOR
(2020:
5.
32
)
(2021:
5.
705
)
(2022:
6.
456
)
OCLC
–
1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
ABSTRACT
An analysis of the performance of quarry hydraulic excavators shows that many excavators used in mining operations
operate at lower productivity than those specified in the technical description. This can be caused by unexpected
interruptions during operation, rapid failure of parts and unreliable operation of excavator personnel.
This article discusses the development of a protective element at the base of the jaw section of an excavator bucket
that is technically and cost-effective in increasing the efficiency of quarry excavators. In addition, the results of
experiments and their analysis of the proposed element of the protection of the base of the improved bucket jaw.
KEYWORDS
Quarry excavator, collapse size, bucket, jaw, protection element, durability, test, performance indicator, rhombus.
Research Article
DEVELOPMENT AND EXPERIMENTAL RESULTS OF A NEW
CONSTRUCTION OF THE ELEMENT OF PROTECTION OF THE BASE OF
THE JAVE PART OF QUARRY EXCAVATORS
Submission Date:
April 09, 2022,
Accepted Date:
April 17, 2022,
Published Date:
April 30, 2022 |
Crossref doi:
https://doi.org/10.37547/tajet/Volume04Issue04-05
Galiya Yeleubaevna Raykhanova
Republic of Uzbekistan, Tashkent region, Almalyk, Totuvlik str.
9-31, Uzbekistan
Rustam Umarhanovich Djuraev
Republic of Uzbekistan, Navoi region, Navoi, Spitamen str., 8 - 21, Uzbekistan
Sardorjon Abdumuminovich Turdiyev
Republic of Uzbekistan, Navoi region, Karmana, Bahor str., 39, Uzbekistan
Journal
Website:
https://theamericanjou
rnals.com/index.php/ta
jet
Copyright:
Original
content from this work
may be used under the
terms of the creative
commons
attributes
4.0 licence.
Volume 04 Issue 04-2022
59
The American Journal of Engineering and Technology
(ISSN
–
2689-0984)
VOLUME
04
I
SSUE
04
Pages:
58-67
SJIF
I
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FACTOR
(2020:
5.
32
)
(2021:
5.
705
)
(2022:
6.
456
)
OCLC
–
1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
INTRODUCTION
In solving the problems of quarry excavators in
excavation and loading, it is important to consider the
construction of these bucket elements, one of the
parts of which creates a high load with rocks of various
physical and mechanical properties. This leads to the
appearance and development of the following types of
defects:
Deformation of the walls on the inside and outside;
Deformation of connected parts and technological
holes (critical change);
A change in the geometry developed by the
manufacturer, ie a shift forward or backward
relative to the central axis.
In all these cases, the excavator bucket needs to be
repaired, which consists of lining (i.e. covering the
worn surfaces with a protective layer), closing the
cracks, replacing the jaw part, increasing the strength,
repairing the defects and restoring the original shape.
MATERIALS AND METHODS
Repairs are carried out using milling and welding
equipment (argon and electric arc), abrasive cleaning,
grinding, final painting.
An overview of quarry hydraulic excavator buckets is
shown in Figure 1 [1].
(a) is a straight shovel and (b) is a reverse shovel
Figure 1. General view of quarry hydraulic excavator buckets
Replacement parts that protect the bucket (lining,
interdental and corner protectors) Hardox-400, -450, -
500 steels, special corrosion-resistant coatings made
of carbide alloys (coating plates ("ESCO"), CDP
("Messer Eutectic Castolin") "), as well as lining
elements made of white chrome cast iron.
There are standard, reinforced, and highly reinforced
types of protection for straight shovels, depending on
where they are used [2].
The lightest bucket of the standard type without
additional protection. Designed to work on less stable
types of rock that do not require special protection
(made of 10XSND, 09G2, Hardox steels) (Figure 2 a).
The bucket used in the reinforced quarries is
additionally reinforced with Hardox-500 corrosion-
resistant plates and other additional protective
elements (made of Hardox, Hardox-HiTuf, Weldox
steels). It can be used in many types of rocks (Figure
2b).
Volume 04 Issue 04-2022
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The American Journal of Engineering and Technology
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VOLUME
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58-67
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(2022:
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OCLC
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METADATA
IF
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7.856
Publisher:
The USA Journals
The high-strength cast iron, in addition to the hardened
cast iron, is protected by carbide alloy plates and cast
elements made of white chrome cast iron. It is
designed to work in particularly difficult conditions
with high abrasiveness of high-density rocks (made of
Hardox, Hardox-HiTuf and Weldox steels with
protection from carbide alloys) (Fig. 2 v).
1 - cutting edge, 2 - side wall of the jaw part, 3 - fastening parts of the back and jaw part of the bucket, 4 - side cutter, 5 - lower
part of the jaw, 6 - tooth system (adapter and tooth), 7 - protection element between teeth, 8 - div, 9 - div protection
element, 10 - corner protection element, 11 - lower jaw and side wall protection element, 12 - external protection elements
Figure 2. Types of protection for straight shovels:
a - standard; b - reinforced; c - highly reinforced
Among the protective elements of the bucket
discussed above, the parts that create a high load
under the interaction with the rocks are the jaw part
after the cutting elements [3].
The jaw is used as one of the key elements of a straight
bucket quarry excavator, which is the moving element
of the bucket. When the back wall of the bucket is in
good condition and for additional economic savings,
only the bucket jaw can be replaced separately. In
order to increase the strength of the jaw structure and
to resist abrasive erosion, additional internal and
external castings made of high-strength steel with a
hardness of 500-600 HB according to Brinell are used.
It is equipped with teeth, adapters, interchangeable
sturdy side cutters, a guard between the teeth with
welded elements, welded elements to protect the
corners of the lower part.
Quick breakdown of the jaw surface of quarry hydraulic
excavators leads to an increase in the duration of
repairs and costs [4].
The protection of straight shovels according to the
place of use should increase the service life based on
the reduction and elimination of erosion and damage
of bucket parts, however, Quarry hydraulic excavators
used in open pit mines of NMMC JSC The following
factors have been identified by investigating the
factors affecting the degradation rates of the
protective elements of the 'section and the resulting
faults.
Volume 04 Issue 04-2022
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The American Journal of Engineering and Technology
(ISSN
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VOLUME
04
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58-67
SJIF
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(2020:
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(2022:
6.
456
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OCLC
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1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
As a result of the breakdown of the protective
elements of the bucket part, the cutting edge of the
bucket part does not pass, which results in fractures of
the bucket part during operation, which is shown in
Figure 3.
Figure 3. The fracture state of the cutting edge of the jaw
Analysis of the results of the above studies shows that
most of the faults in the jaw part of the quarry
hydraulic excavators used in open pit mining are
insufficient protection elements of the jaw part, low
strength and resistance to erosion, ie different types of
excavated rock It quickly loses its properties when
exposed to rocks, and as a result, the jaw part quickly
erodes, leading to failure of other parts of the
excavator and a decrease in operational performance
[5].
In view of the above, it is important to develop
technical solutions to increase the service life and
efficiency of the jaw part elements of quarry hydraulic
excavators.
THE MAIN PART
Today, quarry hydraulic excavators are equipped with
special protective elements on the base and side walls
to ensure that the jaw section is corrosion-resistant,
durable and long-lasting. HITACHI EX-1200 quarry
hydraulic excavators currently use plate-shaped
coatings to protect the base of the jaw section, and the
location and dimensions of the plate-based base
coatings at the base of the bucket jaw section are
shown in Figure 4 [6].
Volume 04 Issue 04-2022
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The American Journal of Engineering and Technology
(ISSN
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(2022:
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OCLC
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METADATA
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–
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Publisher:
The USA Journals
Figure 4. Location and dimensions of the base plates in the form of plates at the base of the jaw
As can be seen from Figure 4, 40 rectangular plates are
welded to the base to protect the base of the jaw. Each
plate weighs 6.9 kg, is 500 mm high, 100 mm wide and
14 mm high. The distance between each coating is 30
mm.
Currently, the service life of the above-mentioned
protective element, which is used to prevent the
collapse of the base of the jaw section of quarry
excavators, is 30-35 days. This means that every 30-35
days, the excavator bucket requires re-coating of the
jaw protection elements with new coatings. Repair
work, on the other hand, increases operating costs as
a result of labor time, labor, and materials required for
welding (gas, electrodes) [7].
With the above in mind, it will be possible to increase
the productivity of the excavator by reducing the
operating costs of the excavator by increasing the
durability and strength of the protective elements of
the jaw part of the excavator bucket and producing a
relatively lightweight improved design.
During theoretical and industrial studies, observations
of the operation of the jaw part protection elements
revealed the need to increase the strength of the base
and side walls of the jaw part, which make the most
contact with the rocks. To this end, an improved
rhombus-shaped protective element has been
developed to increase the efficiency of the quarry
excavators ’operating mode, in exchange for
increasing their resistance to collapse.
In the process of developing the protective elements,
it was taken into account that large fragments of rock
can withstand strong blows to the jaw and reduce
erosion by leaving the crushed rock within the
developed protective elements.
This improved protection element is designed to
penetrate rock with a length of 700 mm and a width of
300 mm. listed.
Volume 04 Issue 04-2022
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The American Journal of Engineering and Technology
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OCLC
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METADATA
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Publisher:
The USA Journals
Figure 5. The rhombus-shaped jaw is a protective element
The length and width of the rhombuses are 200 mm
and 173 mm, respectively. The distance between the
rhombuses and the side wall is 50 mm. The height of
the protection element is 20 mm.
12 of these protection elements can be installed on the
base of the bucket jaw, and the location of the
rhombus-shaped protection element on the base of
the bucket jaw is shown in Figure 6. The distance
between each protective element is 50 mm.
Figure 6. The rhombus-shaped protective element is located at the base of the bucket jaw
EXPERIMENTAL RESULTS
In order to determine the effectiveness of the new
design of the protective element of the jaw part of the
developed excavator bucket, they underwent
experimental tests.
During the experimental work, the abrasion resistance
of the protective elements of the base of the jaw part
of the excavator bucket, ie their service life, was
studied.
The following machines and equipment were used
during the experiments:
•
HITACHI EX-1200 Quarry hydraulic excavator;
•
protective elements of the base of the base and
rhombus-shaped jaw;
•
electronic caliper;
Volume 04 Issue 04-2022
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OCLC
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Publisher:
The USA Journals
•
Rocks with explosive hardness f = 12 ÷ 14.
The experimental work was carried out in the following
stages:
In the first stage of the experimental test, the
excavation was carried out during the excavation and
loading operations, with the installation of protective
elements in the form of a base plate at the base of the
jaw section. During the experimental tests, it was
determined that the thickness of the basic protective
elements installed on the base of the bucket jaw during
operation for a certain period of time.
In experimental tests, one of the most effective ways
to determine the size change of the base protection
element of the base of the bucket jaw due to frictional
erosion due to its thickness during operation for a
certain period of time is differential (micrometric)
method Δ = 0.1 mm error was carried out using an
electronic barbell caliper, which can be tolerated, and
these results are given in Table 1.
Based on the results of the above experiments, the
dependence of the service life of the protective
element, which has a basic structure, on the base of the
jaw part of the excavator bucket, is shown graphically
in Figure 7 below.
Figure 7. Graph of the magnitude of the breakdown of the basic protective element of the base of the jaw part
As can be seen from the graph of the dependence of
the service life of the base protection element on the
base of the bucket jaw section shown in Figure 7
above, an increase in the failure rate of the protection
element is observed as the excavator service life
increases.
The average lifespan of the jaw section of the
excavator bucket was 400 moto-hours.
In the second stage of the experimental test, the
developed rhombic bucket was implemented during
the operation of quarry excavators with the
installation of a protective element at the base of the
jaw section, without changing the above parameters.
The magnitude of the amount of erosion caused by the
friction of the rock during the full operation of the
protective elements of the base of the developed
rhombus-shaped jaw section during their full service
0
2
4
6
8
10
12
14
16
0
100
200
300
400
500
W
o
rk
in
g
ti
m
e,
T
(m
o
to
-h
o
u
rs)
Erosion size, Δh (mm)
Volume 04 Issue 04-2022
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SJIF
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(2020:
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)
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5.
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)
(2022:
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456
)
OCLC
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METADATA
IF
–
7.856
Publisher:
The USA Journals
life was measured, and these results are given in Table
1. 'shown.
Table 1
The amount of breakdown of the basic and developed protective elements of the base of the jaw part of the
excavator bucket
Working time, moto-hours
The amount of degradation of the
basic protective element Δh, mm
The height of the rhombus-
shaped protective element Δh,
mm
0
0
0
50
1,0
1,0
100
2,0
2,0
150
4,0
3,0
200
6,0
5,0
250
8,0
7,0
300
10,0
9,0
350
12,0
12,0
400
14,0
15,0
420
-
18,0
440
-
20,0
Also, the results of the performance of the new
protective elements of the base of the jaw part of the
excavator bucket, developed during the experimental
work, mentioned in Table 1 above, and on the basis of
these results improved the protective element of the
base of the jaw part of the excavator bucket. the
dependence of the service life of the developed
rhombus-shaped structure on the magnitude of the
collapse was established, and this dependence is
shown in Figure 8 below.
Volume 04 Issue 04-2022
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(2022:
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)
OCLC
–
1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
Figure 8. Graph of the magnitude of the deterioration of the service life of the improved rhombic protective
element of the base of the jaw part
As can be seen from the graph of the dependence of
the service life of the bucket jaw part with the
improved rhombus shape shown in Figure 8 above, the
rhombus-shaped bucket jaw as a result of the increase
in service life every 50 moto-hours. The magnitude of
the erosion on the thickness of the protective element
of the base of the part was 1-2 mm during the initial
working hours of the protective element, ie up to 250
moto-hours. During the next 250 to 460 moto-hours of
operation, every 50 moto-hours was 3-5 mm.
The average lifespan of the jawbone of the excavator
was 460 moto-hours.
CONCLUSION
Based on the results of the experimental studies,
graphs of the magnitude of the collapse of the
protective plate with the base plate and improved
rhombic shapes of the base of the jaw section were
established and their mutual comparison garden The
gravity graph is shown in Figure 9.
1 - basic protection element; 2 - rhombus-shaped protective element
Figure 9. Graph of the basic and improved protective elements of the base of the jaw part of the excavator bucket
depending on the rate of deterioration
0
3
6
9
12
15
18
21
0
100
200
300
400
500
W
o
rk
in
g
t
ime
,
T
(
mo
to
-h
o
u
rs)
Erosion size, Δh (mm)
0
2
4
6
8
10
12
14
16
18
20
22
0
50 100 150 200 250 300 350 400 420 440 460 480
W
o
rk
in
g
tim
e,
T
(m
o
to
-h
o
u
rs
)
Erosion size, Δh (mm)
Volume 04 Issue 04-2022
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The American Journal of Engineering and Technology
(ISSN
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2689-0984)
VOLUME
04
I
SSUE
04
Pages:
58-67
SJIF
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FACTOR
(2020:
5.
32
)
(2021:
5.
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)
(2022:
6.
456
)
OCLC
–
1121105677
METADATA
IF
–
7.856
Publisher:
The USA Journals
As can be seen from the graph of the bucket jaw part
protection elements with the basic and improved
rhombus shape shown in Figure 9 above, the
dependence of the magnitude of the fracture on the
thickness of the working life is improved relative to the
basic protection element. The working life of the
protective element of the jaw part of the bucket with a
rhombus shape was found to be 60 moto-hours, ie 15%
more time performance, the jaw part is 24 kg lighter
and consumes less metal.
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Poderny R.Y. Analysis of the current state of the
quarry machinery market in the world // M.: Mining
Industry, 2013. - №4 (110).
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Turdiyev S.A and Jurayev A.Sh 2022. Study of the
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Abduazizov N.A., Mahmudov Sh.A., Turdiyev S.A. A
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Turdiyev S.A., Djurayev R.U., Jo`rayev A.Sh.
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