mining engineering: Excavators/Backhoe

Features

Dash-7 Series

High production and low fuel consumption

• Working mode selection

Dash-7 excavators are equipped with three working modes (A, E and B mode).

Production is increased with larger output during Active mode while efficiency is further improved.

• Larger digging power provides increased production

Bucket digging force and bucket digging speed are increased, so resulting total bucket digging force increased.

(PC200-7, PC220-7)

Example: PC200-7

Bucket Digging Force Bucket Digging Speed Bucket Digging Power

• Larger arm crowd force and digging force provide increased production (PC300-7, PC350-7)

• Large lifting capacity

Lateral stability is improved resulting in increased lifting capacity.

• Larger maximum drawbar pull

Maximum drawbar pull is increased, provides superb steering and slope climbing performance.

• Power max function

This function temporarily increases digging force by 7% for added power in tough situations.

• Two boom settings

Smooth mode provides easy operation for gathering blasted rock or scraping down operation. When maximum digging force is needed, switch to Power mode for more effective excavating. (PC300-7, PC350-7)

Harmony with environment

• Low emission engine

Komatsu SAA6D102E-2 and SAA6D114E meets EPA, EU and Japan Tier ll emissions regulations.

• Environment oriented mode (Economy mode)

Economy mode offers the user fuel savings, quiet operation and less CO2 emission.

Large comfortable cab

• Large-sized cab

New cab volume is increased by 14%.

• Pressurized cab

With optional air conditioner, air filter and higher internal air pressure prevent external dust from entering the cab.

• Low noise

Noise is reduced not only from the engine but also during swing and hydraulic relief.

• Low vibration with cab damper mounting

The new cab damper mounting combined with strengthened left and right side decks aids vibration reduction at operator seat.

• Automatic air conditioner (Optional)

A 6,900 kcal (SAE) air conditioner is utilized.

Series Selection

The AVANCE line-up is expanded, with different excavator series for different jobs.

You can choose the right machines for your work, factory-equipped for your operation.

• “Dash-7” Series, AVANCE "Standard" Series

Flexible, efficient excavators for a wider range of work

• AVANCE "Mighty" Series

Extra-strong excavators for mining, quarrying and demolition

• AVANCE "HD" Series

"Heavy-duty" excavators with reinforced undercarriages for logging and scrap handling

• AVANCE "EXCEL and Custom" Series

Simple, basic excavators for easy operation and maintenance

• AVANCE "US" Series

Excavators with short tail swing profile for work on road ways,urban areas and logging road way Series selection by industry segment and application

Remarks: O - Optimum who require the following benefits. @- Possible

* EXCEL and CUSTOM models are recommendable to customers

Customers benefit

1. Simple operation

2. Simple maintenance & repair by customer

3. Dusty or marsh land - concern about mechatronics

4. Initial cost low - modification to install attachment

** When using hydraulic breaker, reinforcement of arm is required.

*** Modification of machine body by attachment maker, is required for PC200 / 220.

Specifications

* Operating weight includes coolant, lubricants, full fuel tank, operator 80kg(180lb) and, indicated implement, shoes and upper attachment.

Dimensions

Working Ranges and Digging Forces

** ISO rating

Component Dimensions and Weights

* UK source

Shoe selection

Semi-Double grouser shoes

These shoes offer two grousers of different heights (9). The designed heights are in between the single and triple-grouser shoes. As a result, excellent maneuverability, large traction and excellent groundbiting ability are obtained. To prevent shoes from becoming bent due to heavy loads, grousers with added thickness (10) provide maximum rigidity.

Triple-grouser shoes

On hard-ground surfaces, where it is impossible for grousers to penetrate the ground to hold the ground firmly with strong pressure advance the machine positively, triple-grouser shoes offer three grousers of the same height (12). Machine maneuverability is the results. And besides improving operator comfort, these shoes are less likely to become bent on hard terrain as compared to semi-double-grouser's biting depth.

Rubber shoes (Monolithic type)

Rubber shoes are suitable for traveling on paved roads without damaging their surface. Rubber shoes feature lower noise and less vibration than iron shoes.

Rubber pad shoes

For larger capacity and more power, count on medium-class hydraulic excavators equipped with rubber pad shoes. Rubber pad shoes provide the same strength as conventional tracks but with a smooth, quiet and gentle grip.

A blend of natural and synthetic rubbers assures maximum strength. This durable, hard material is baked onto the metallic triple-grouser shoe. As a result, the total shoe assembly is as strong as conventional shoes.

Komatsu swamp shoes (circular arc shoes)

Komatsu swamp shoes (circular arc shoes) were developed specifically for use in swampy or muddy terrain, or soft soils. These shoes have the following advantages:

• Less mud sticks to the shoe surface

• Will not damage compacted ground surface

Self cleaning effect of the swamp shoes

Komatsu swamp shoes with increased traction, have solved both problems. As shown in the right figure, the advanced circular arc shoe, moves along the compacted ground surface while maintaining an equal radius from link center "A". As the machine moves forward, tracks left by preceeding shoes, are traced precisely by the shoes that follow. As a result, the walls of compacted ground are neither scraped nor damaged, with minimal mud sticking to shoes.

Large traction of the swamp shoes

The larger the shoe-to-mud coefficient of traction and ground contact area is, the greater the traction is. On water-soaked and soft soil, coefficient traction is lower as traction is reduced. The reason why Komatsu swamp shoes obtain such large traction is due to their larger ground contact area and unique shoe shape which do not damage compacted ground surfaces.

Shoe Application

Ground Pressure

Definition: Ground pressure = machine operating weight / total ground contact area

where ; total ground contact area = (L + 0.35H) × shoe width × 2

* Standard shoe

NOTE: The shoe for the long-track excavator (L and LC), wide shoe (excluding the narrowest shoe for a model) and swamp shoe are provided with low ground pressure. These shoes should be used on soft and swampy terrain where the standard excavator with standard shoe is not usable due to sinkage of the tracks. If such shoes are used in swampy fields with stones, stumps and roots, bending of the shoe plates, cracks in the links, breakage of pins, loosening of shoe bolts and other damage may result. Therefore, the job site must be studied carefully, to provide the customer with correct instructions and advice.

Bucket Capacity Definition

BUCKET CAPACITY RATING

Bucket capacity is measured in terms of either struck or heaped capacity. Generally, the heaped capacity description is more frequently used. Komatsu Ltd. rates the excavator bucket capacity based on ISO and other standards such as JIS, PCSA and SAE (JIS and SAE are based on ISO.)

1) Struck Capacity

The struck capacity is the volume capacity of the bucket after it has been struck at the strike plane. The strike plane passes through the top back edge of the bucket and the cutting edge. (See top figure at right)

2) Heaped Capacity

The heaped capacity is the sum of the struck capacity plus the volume of material heaped on the bucket at a 1:2 angle of repose, as shown in the center figure at right. This in no way implies that the hoe must carry the bucket oriented in this attitude, or that all material will naturally have a 1:2 angle of repose.

Vh=Vs+Ve

Where:

Vs: struck capacity

Vh: heaped capacity

Ve: excess material heaped at 1:2 angle of repose

There are various standards for designating the heaped capacity of the bucket.

The principal difference among these definitions is the ''angle of repose'', as listed in the table below.

The angle of repose

Notes:

ISO........International Organization of Standerd - ISO 7451 and ISO 7546

JIS.........Japanese Industrial Standard - JIS A8401 - 1976

PCSA ....Power Crane and Shovel Association (USA) - PCSA No.37-26

SAE.......Society of Automotive Engineers (USA) - SAE J296/J742b

CECE....Committee of European Construction Equipment - CECE SECTION VI

Bucket Selection

Bucket selection for excavator

Komatsu offers various kinds and sizes of buckets so that the users are able to select the optimum bucket for

the type of soil and the work to be performed. This enables the work to be accomplished most efficiently.

The following is a guide for selecting the optimum bucket.

1. Selection of type (shape)

Various types can be attached to excavators.

• General purpose bucket

• Light duty bucket

• Heavy duty bucket

• Narrow bucket (Ditch bucket)

• Rock bucket

• Ripper bucket

• Other special buckets

The appropriate type should be selected for each job application. It is recommended to ask the Komatsu distributor about the availability of necessary buckets. When the necessary bucket is not currently available, the distributor can request Komatsu to develop it.

2. Selection of size

The following two points 1) and 2) should be considered altogether.

1) From the machine stability (For backhoe type)

If the bucket size (capacity) is too big, it will worsen the stability of the machine, resulting in danger of tipping over or rolling over. The concept of the bucket selection from the point of machine stability is from the following. Putting A as the maximum allowable load from over-side (sideways) machine stability and B as the

bucket working load (bucket weight + carrying material weight), the size of the bucket should be selected so as to be;

B = A

From Figure 1,

A = W1 + (L0 / L) W2 = W1 + W2 Approximately

where,

W1 : The weight of the empty bucket shown in the table of Lift Capacity. The value of the weight is shown in the tables of "Bucket and Arm Combination".

W2 : The smallest lift capacity in the table of Lift Capacity at respective boom length and arm length (The lift capacity differs by the arm vertical position)

From Figure 2,

B = W3 + W4

where,

W3 : The bucket weight used for the job

W4 : The weight of carried material

(= rated bucket capacity × specific gravity of carried material)

Bucket and Arm Combinations

This shows the bucket sizes currently available for respective models produced in various Komatsu plants, in

relation with the arm length. All allowable sizes from the concept of machine stability in "BUCKET SELECTION" are not shown, but it is possible for Komatsu plants to develop the various size buckets according to the theory of "BUCKET SELECTION", if it is requested through a distributor.

The theory of "BUCKET SELECTION" can be applied when a bucket is procured from a local attachment manufacturers. But the quality of the bucket from a local supplier can not be guaranteed by Komatsu.

* Strengthened bucket

*** Without side cutters

Teeth Features and Teeth Selection

Teeth Features

1) Long-life bucket tooth:

Fits the work site where wear resistance of the tooth is required because it must be used to collect sand and gravel.

2) Self-sharpened bucket tooth:

Fits the work site where penetration ease of the tooth is required because it must be used to dig rock and clay after blasting.

3) Super self-sharpened bucked tooth:

Fits the work site where penetration ease better than above is required because it must be used to dig rock after blasting.

4) Standard bucket tooth:

Fits other general work sites.

Teeth Selection

1. Teeth designed by Komatsu

O : Available

2. Hensley teeth

1) General information for ‘5’ Series / Parabolic? / Hammerless Teeth

Model Selection

1. Basic idea for excavator selection

The concept of the combination of bucket size, arm length, and boom length for hydraulic excavators to match the nature of the operation is as follows.

2. Wrong combination

1) Long Arm with Large Capacity Bucket

If the machine is operated with a long arm and a large capacity bucket with a capacity larger than recommended, the machine will become unstable, and it will also lose digging power, so the operating efficiency will drop. In particular, if a strong shock load is applied to the bucket, there is danger that the arm may break.

2) Additional Counterweight

If an excessive capacity bucket or heavy attachment is installed, the machine will become unstable, so it is common to see additional counterweights used. However, this means that an excessive load is applied not only to the work equipment and undercarriage, but also to the whole machine, so this will lead to a reduction in the service life of the machine.