Clamshell buckets are construction equipment used for digging and material handling. They are bucket attachments with two hinged halves that open and close like a clam shell. There are several types of clamshell buckets classified by operation method (hydraulic, mechanical via cables) and size (light to extra heavy duty). They are used for applications like excavation, dredging, loading/unloading trucks. Proper maintenance and task planning is important when using clamshell buckets to ensure safety. Key factors in clamshell bucket selection include the material properties and quantities to be moved.

1. CLAM SHELL
CONSTRUCTION EQUIPMENT
BY AKANKSHA PENDHARKAR

2. SIZE OF CLAMSHELLS BUCKETS :
• Clamshells buckets are available in various sizes; and in
heavy duty type for digging, medium-weight type for
general purpose, medium light-duty type for handling
light materials.
• Buckets may have teeth that can be easily removed or
they may be without teeth. Teeth are used in digging
harder types of materials but are not required when a
bucket is re-handling materials.
The clam-shell bucket is a sophisticated articulating two-piece bucket
mechanically hinged at the middle to form a claw-like appendage with an
internal volume.
• Clamshells are used primarily for handling loose materials such as sand, gravel,
crushed stone, etc. and for removing materials from cofferdams, pier foundations,
etc.
• They are specially suited to vertical lifting of materials from one location to another.
The limit of vertical movement maybe relatively large when they are used with long
crane booms.
1.WHAT IS CLAM-SHELL BUCKET?
https://eikengineering.com/products/grab-series/clamshell-bucket/

3. https://www.researchgate.net/figure/Structure-of-clamshell-grab_fig1_330558119
CLAMP-SHELL
COMPONENTS

4. This classification is done mainly based on the operating method
And purpose of using.
2. TYPES OF CLAMP-SHELL BUCKETS
HYDRAULIC
CLAM-SHELL BUCKET
MECHANICAL/CABLE
CLAM-SHELL
BUCKET
HYDRAULIC CLAM-
SHELL
FOR TELESCOPIC ARM
1 2 3
https://aprgrabs.com/mechanical-clamshell-bucket/

5. • Hydraulic clamshell grab bucket is an equipment creation with two shells,
controlled by hydraulic cylinder with one, two or four cylinders available can be
horizontal or vertical mounted.
• Clamshell bucket can be used for loading & digging or dredging purposes.
• Hydraulic clamshell bucket can be execute work (load) precisely such as wood chips,
waste, paper, sand, dirt, mud, & food etc.
• hydraulic clamshell buckets can be installed on
fixed cranes, truck, forestry cranes, excavators,
crawlers and so on.
• Bucket have two types as light & heavy.
• Light bucket used for handle waste, dirt as other
hand heavy models used for intensive heavy work.
FEATURES:
•Sturdy structure with high tensile steel.
•Anti-wear manganese steel teeth built grabs.
•Grab specially build from 0.75 cbm up to 30 cbm.
•Reduced height, multi-stable, can work at any angle.
•Hydraulic rotator for 360˚ rotation.
HYDRAULIC CLAMPSHELL BUCKET
https://aprgrabs.com/mechanical-clamshell-bucket/

6. • The Mechanical Clamshell is designed specifically to be used on a crane for
large capacity dredging and digging applications.
• The opening and closing action is operated via cable.
• The inner side of the bucket has a smooth surface for easy unloading of high viscosity
material such as mud and clay, while the outer layer is reinforced with an additional layer
of wear strips.
• The hanger is constructed with high tensile steel.
• Opening and closing scoop grabs is operated through rope cable. It gives an advantage
when bulk materials with various densities are discharged.
MECHANICAL CLAMPSHELL BUCKET
https://aprgrabs.com/mechanical-clamshell-bucket/

7. • These are specially
designed clamshell buckets
for use with cranes that are
not equipped with
independent holding and
closing lines.
• simple to operate.
• Single rope clamshells can
be used to unload bulk
material for large land
work projects or to remove
aggregates during dredging
operations.
• Two Rope Clamshell
buckets for two line
operated cranes (One
Holding Rope and One
closing Rope).
• These grabs are especially
designed for charging and
discharging gravel, sand
and other bulk materials.
• The grabs are
manufactured of anti-
abrasive steels. sheaves
bearings are heavy duty
and sealed for optimal
performance.
https://aprgrabs.com/mechanical-clamshell-bucket/
SINGLE ROPE FOUR ROPE
TWO ROPE
• These are specially
designed clamshell buckets
for use with cranes that are
not equipped with
independent holding and
closing lines.
• simple to operate.
• Single rope clamshells can
be used to unload bulk
material for large land
work projects or to remove
aggregates during dredging
operations.
• Four Rope Mechanical
Clamshell Grabs are used
for attachment to four line
operated large cranes, two
Holding Ropes and Two
Closing Ropes.
• It is an excellent tool for
charging and discharging
sands, coal, mineral
powder and bulk chemical
fertilizer. electricity, vessel,
metallurgy, preservation
and transportation, and
are exported in quantities.

8. • Productive Deep-Digging Excavator with Clamshell Telescopic Arm.
• The clamshell telescopic arm allows the excavator to dig deep underground,
down to a depth of 25 m, and to load a truck with a short cycle time,
increasing uptime and production.
Clamshell Telescopic Arm
• The clamshell telescopic
arm gives dynamic actions
for productive underground
excavation by a
combination
• of ropes and hydraulic
cylinders.
• Bucket capacity: 1.30 m3
• Digging depth: 25.0 m
HYDRAULIC CLAMPSHELL FOR TELESCOPIC ARM

9. HYDRAULIC CLAMPSHELL
FOR TELESCOPIC ARM

10. COUNTERWEIGHTS
• Two types of counterweights,
a standard heavier type and an optional
put-on type,are available.
TWIN-ROPE SYSTEM
• The twin-rope system makes the machine
safe further. Even if one of the twin ropes
breaks accidentally, the other can hold the
telescopic arm in position.
SLIDING CAB
• The cab on the clamshell telescopic
arm excavator is positioned forward,
to allow the operator to look down
deep excavation from the operator’s
seat for confident excavation.
• The cab can further slide forward
• A walkway and handrail are deployed
for easy access to the cab.
• Sliding stroke distance: 1 300 mm
HYDRAULIC CLAMPSHELL FOR TELESCOPIC ARM
SLIDING CAB COUNTERWEIGHTS
TWIN ROPE
SYSTEM

11. THE TYPES OF GRAB BUCKET CAN BE DIVIDED ACCORDING TO THE
VOLUME DENSITY OF GRASPING MATERIALS
• Light , Medium , Heavy , Extra-heavy type.
• These four different types of grab bucket, in order to adapt to different volume
density materials, in the case of the same volume, the weight of the grab bucket has
a big difference.
ACCORDING TO THE DRIVING MODE OF CLOSURE AND OPENING OF THE
JAW PLATE, THE GRAB CAN BE DIVIDED INTO:
Rope type: the rope grab relies on the wire rope to create a closed force to achieve the
purpose of grasping the material. The rope grab is divided into single rope, double rope
and four-rope grab.
Power grab: power grab through the load on the power unit and the transmission device
to open and close the jaw plate, such as: electric grab, motor grab.

12. DOUBLE JAW PLATE GRAB
WOOD GRAB BUCKET
SCISSOR GRAB BUCKET
ELECTRIC MOTOR GRAB
MULTI-VALVE TYPE GRAB BUCKET
ELECTRIC HYDRAULIC GRAB

13. 3. SELECTION CRITERIA FOR EQUIPMENT
There are many types of factors behind the selection of construction equipment, and the
types are completely describe below
• Economic Consideration.
The economic consideration such as owning costs and operating fuel costs of equipment,
the resale value, the replacement cost , salvage value
are most important in selection of equipment.
• Site Specific.
Site condition, both ground conditions as well as climatic conditions may affect the
equipment selection decision.
• Equipment Specific.
Construction equipment come with high price tags.
• Client and project Specific.
The owner/client in acertain project may have certain preferences that are no in
line with the construction companys preferred policies as far as equipment procurement
is concerned.
• Manufacturer Specific.
A construction company may prefer to buy equipment from the same manufacturer again
and again, and that too from a specific dealer.
• Labor Consideration.
Shortage of manpower in some situations may lead to decision in favor of procuring
equipment that is highly automated.

14. 4. SELECTION CRITERIA FOR CLAMSHELL
• Quantities of material to be moved
• The available time to complete the work the job conditions
• The prevailing soil types, the swell and compaction factors, etc.
• The job conditions include factors such as availability of loading and
dumping area, accessibility of site, traffic flows and whether conditions at
site
• In order to plan the number of earthwork equipment needed, the planner
first determine the following:-
The suitable class of equipment for earthwork-for example, if the soil
to be excavated is loose and marshy, and bulk excavation is involved
in the project, one may optimized for a dragline.

15. When working with any type of equipment, it is critical that a thorough pre-use
inspection be performed.
Proper task planning helps to ensure that:
• Everyone involved in the work activity is aware of what the team is doing.
• Each individual is aware of his/her responsibility.
• The correct tools and equipment are available.
• Potential hazards are identified and mitigated.
• Clamshell dredging is a duty cycle process and will require more frequent planned
maintenance. This will allow you to be prepared at all times and help to eliminate
surprises; it also prevents overlooking of maintenance while focusing on other areas of
the work, such as the spoils pile.
Following are several items to consider during the development of a task plan for
clamshell dredging operations.
Condition of equipment:
--Is the crane the right size and type for the operation?
--Have the crane and components been properly inspected?
--Has the clamshell bucket been properly sized and inspected?
--What potential hazards were found during inspection of the equipment?
--Is all required equipment documentation current and available?
5.TASK PLANNING FOR GREDGING WITH CLAMPSHELL

16. EQUIPMENT SETUP
--How stable and level is the surface area upon which the crane and the clamshell, and other
associated equipment, will be set?
--What size equipment mats are needed?
--Have measures been taken to prevent the bucket from opening while unloading/loading?
--Are there structures (buildings, trees, electrical lines or poles, bridges, pipes, etc.) that have
the potential to contact any part of the crane or its attachments during operation (think 360s)?
--Has personnel access to the swing area and load travel path been closed and properly
barricaded so nobody will be under a load?
--Have all equipment, materials and other items that could be damaged by a falling load been
moved out of the swing area and travel path or otherwise been protected?
--Are there vibrations from other sources (local traffic, work operations, etc.) that may pose a
potential settling or tipping hazard to the equipment or clamshell bucket while set stationary
or during operation?
5.TASK PLANNING FOR GREDGING WITH CLAMPSHELL

17. SCHEDULED AND UNSCHEDULED MAINTENANCE
--Is time scheduled to inspect and service the boom, wire rope, and sheaves of the crane
at least twice per shift and the bucket pins, arms, teeth, sheaves, and ropes even more
often?
--Have the area and equipment been identified so the bucket can be blocked, secured,
and prevented from opening while being serviced?
--Has the "Jack line," or closing line, been prepared in advance to be replaced on a
regular basis prior to its breaking?
--How will the bucket be kept secured in the event of a wire rope or pin failure?
Protection of the public and other workers:
--Is the public protected from access to the work site?
--Are other workers able to maintain a safe distance from the clamshell operations?
--Has the spoil removal process been set up to limit exposure to other workers and the
public?
5.TASK PLANNING FOR GREDGING WITH CLAMPSHELL

18. • Digging pits for ground construction work.
• Ideal for digging and loading material in tight and limited spaces.
• Material handling, loading and unloading industrial wastes, grains, sands, etc.
• Heavy duty mechanical clam-shell is ideal for dredging application by crane.
6.APPLICATIONS

19. • Clamshell Grab Buckets for Mucking -foundation well mucking.
• Rehandling Clamshell Buckets-These are widely used for many industrial purpose of
transferring products from one place to other.
• Hydraulic clamshell buckets - commonly used to carry aggregates such as earth,
sand and gravel.
• Single rope cable clamshell buckets – these are more heavy duty clamshell buckets are
are typically used on cranes
• Two Line Digging Buckets-powerful earth-moving for large projects that can range
from commercial, civic, or marine applications. These buckets are used with cranes
• Digging clamshell bucket – as the name suggests, this is the clamshell bucket of choice for
excavation work where heavy loads are to be dug and moved out.
• Rock Grapples-Ideal for moving aggregates, creating construction driveways, jetties, and
other large rock features. These can also be used to remove rocks and debris from soil
efficiently or clear land before a piling project begins.
• Electro-Hydraulic Buckets- marine or terrestrial projects
• Ore Buckets-heavy loads and operate in any conditions for transporting large amounts of
aggregate.commonly used in mining operations.
6. APPLICATIONS ACCORDING TO TYPES OF BUCKETS

20. • CYCLE TIME (TCYCLE) -The cycle time is the total time required for the dredge to
empty, move to the desired location, fill the bucket and empty it. As the cycle time
increases, so does the project length, and therefore cost.
• SWING ANGLE (ΘSW) -The first parameter is swing angle()sw θ. The swing angle is
the difference between the location where sediment is dropped into the hopper barge and
the location where the sediment is excavated.
• SWING SPEED (ΩSW) -Swing speed ()sw ω is the rate that the mechanical clamshell
dredge rotates to and from the excavation site and the barge.
• Fall Velocity (uf) The rate or speed at which the bucket is lowered to the bottom is the
fall velocity()f u.
• GRAB TIME (TG)- The grab time ()g t is the time required to close the clamshell on
the sediment and is given in seconds. A common grab time value is 1 second, and it can
be adjusted for buckets of various sizes.
• EMPTY TIME (TE) -The empty time ()e t is the time required for the sediment to leave
the bucket after opening. An average value is 2.6 seconds, which is the suggested
default value.
7. CLAMPSHELL THEORY

21. 8.TOP BRANDS OF CLAMPSHELL
https://blog.iseekplant.com.au/blog/top-ten-heavy-equipment-manufacturers

22. THANK YOU
BY AKANKSHA PENDHARKAR