Nama : Mustofa A.S

Nim : 15028

Bulldozer

bulldozer is a crawler (continuous tracked tractor) equipped with a substantial metal plate (known as a blade) used to push large quantities of soil, sand, rubble, etc., during construction work and typically equipped at the rear with a claw-like device (known as a ripper) to loosen densely-compacted materials.

Bulldozers can be found on a wide range of sites, mines and quarries, military bases, heavy industry factories, engineering projects and farms.The term "bulldozer" is often used erroneously to mean any heavy equipment (sometimes a loader and sometimes an excavator), but precisely, the term refers only to a tractor (usually tracked) fitted with a dozer blade. That is the meaning used here.

Most often, bulldozers are large and powerful tracked heavy equipment. The tracks give them excellent ground hold and mobility through very rough terrain. Wide tracks help distribute the bulldozer's weight over a large area (decreasing pressure), thus preventing it from sinking in sandy or muddy ground. Extra wide tracks are known as 'swamp tracks'. Bulldozers have excellent ground hold and a torque divider designed to convert the engine's power into improved dragging ability. The Caterpillar D9, for example, can easily tow tanks that weigh more than 70 tons. Because of these attributes, bulldozers are used to clear areas of obstacles, shrubbery, burnt vehicles, and remains of structures.The bulldozer's primary tools are the blade and the ripper.

Some bulldozers, especially bulldozers in military usage, have been fitted with armor to protect the driver from enemy fire, enabling the bulldozer to operate in battle zones. The best-known use of an armored bulldozer is probably the use by the Israeli Defence Forces (IDF) of the IDF Caterpillar D9, for earth moving, clearing terrain obstacles, opening routes, detonating explosive charges and demolishing structures whilst under fire. The extensive use of armored bulldozers during the Second Intifada drew controversy and criticism from human rights organizations while military experts saw it as a key factor in reducing IDF casualties.

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Ripper

The Rips machine assigns to a stable isometric action of a finitely generated group G a certain "normal form" approximation of that action by a stable action of G on a simplicial tree and hence a splitting of G in the sense of Bass–Serre theory. Group actions on real trees arise naturally in several contexts in geometric topology: for example as boundary points of the Teichmüller space (every point in the Thurston boundary of the Teichmüller space is represented by a measured geodesic lamination on the surface; this lamination lifts to the universal cover of the surface and a naturally dual object to that lift is an R-tree endowed with an isometric action of the fundamental group of the surface), as Gromov-Hausdorff limits of, appropriately rescaled, Kleinian group actions,and so on.

The use of R-trees machinery provides substantial shortcuts in modern proofs of Thurston's Hyperbolization Theorem for Haken 3-manifolds. Similarly, -trees play a key role in the study of Culler-Vogtmann's Outer space as well as in other areas of geometric group theory; for example, asymptotic cones of groups often have a tree-like structure and give rise to group actions on real trees. The use of R-trees, together with Bass–Serre theory, is a key tool in the work of Sela on solving the isomorphism problem for (torsion-free) word-hyperbolic groups, Sela's version of the JSJ-decomposition theory and the work of Sela on the Tarski Conjecture for free groups and the theory of limit groups.

The ripper is the long claw-like device on the back of the bulldozer. Rippers can come as a single (single shank/giant ripper) or in groups of two or more (multi shank rippers). Usually, a single shank is preferred for heavy ripping. The ripper shank is fitted with a replaceable tungsten steel alloy tip.

Ripping rock breaks the ground surface rock or pavement into small rubble easy to handle and transport, which can then be removed so grading can take place. With agricultural ripping, a farmer breaks up rocky or very hard earth (such as podzol hardpan) which is otherwise unploughable, in order to farm it. For example, much of the best land in the California wine country consists of old lava flows. The grower shatters the lava with heavy bulldozers so surface crops or trees can be planted.

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Power Shovel

Power shovel (also stripping shovel or front shovel or electric mining shovel) is a bucket-equipped machine, usually electrically powered, used for digging and loading earth or fragmented rock and for mineral extraction. Shovels normally consist of a revolving deck with a power plant, driving and controlling mechanisms, usually a counterweight, and a front attachment, such as a boom or crane which supports a handle with a digger at the end.

The machinery is mounted on a base platform with tracks or wheels.The bucket is also known as the dipper. Modern bucket capacities range from 8 m3 to nearly 80 m3 Power shovels are used principally for excavation and removal of overburden in open-cut mining operations, though it may include loading of minerals, such as coal. They are the modern equivalent of steam shovels, and operate in a similar fashion.

The shovel operates using several main motions:

hoist - pulling the bucket up through the bank (i.e. the bank of material being dug) crowd - moving the dipper handle out or in to control the depth of cut and when

positioning to dump swing - rotating the shovel between digging and dumping propel - moving the shovel unit to different locations or dig positions

A shovel's work cycle, or digging cycle, consists of four phases:

digging swinging dumping returning

The digging phase consists of crowding the dipper into the bank, hoisting the dipper to fill it, then retracting the full dipper from the bank. The swinging phase occurs once the dipper is clear of the bank both vertically and horizontally. The operator controls the dipper through a planned swing path and dump height until it is suitably positioned over the haul unit (e.g. truck).

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Motor Grader

grader, also commonly referred to as a road grader, a blade, a maintainer, or a motor grader, is a construction machine with a long blade used to create a flat surface. Typical models have three axles, with the engine and cab situated above the rear axles at one end of the vehicle and a third axle at the front end of the vehicle, with the blade in between. In certain countries, for example in Finland, almost every grader is equipped with a second blade that is placed in front of the front axle. Some construction personnel refer to the entire machine as "the blade."

In civil engineering, the grader's purpose is to "finish grade" (refine, set precisely) the "rough grading" performed by heavy equipment or engineering vehicles such as scrapers and bulldozers.Graders can produce inclined surfaces, to give cant (camber) to roads. In some countries they are used to produce drainage ditches with shallow V-shaped cross-sections on either side of highways.

Graders are commonly used in the construction and maintenance of dirt roads and gravel roads. In the construction of paved roads they are used to prepare the base course to create a wide flat surface for the asphalt to be placed on. Graders are also used to set native soil foundation pads to finish grade prior to the construction of large buildings.

In some locales such as Northern Europe, Canada, and places in the United States, graders are often used in municipal and residential snow removal. In scrubland and grassland areas of Australia and Africa, graders are often an essential piece of equipment on ranches, large farms, and plantations to make dirt tracks where the absence of rocks and trees means bulldozers are not required. A more recent innovation is the outfitting of graders with GPS technology, such as manufactured by Topcon Positioning Systems, Inc., Trimble Navigation, Leica Geosystems or Mikrofyn for precise grade control and (potentially) "stakeless" construction.

Capacities range from a blade width of 2.50 to 7.30 m and engines from 93–373 kW (125–500 hp). Certain graders can operate multiple attachments, or be used for separate tasks like underground mining.

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Loader

loader is a heavy equipment machine often used in construction, primarily used to load material (such as asphalt, demolition debris, dirt, snow, feed, gravel, logs, raw minerals, recycled material, rock, sand, and woodchips) into or onto another type of machinery (such as a dump truck, conveyor belt, feed-hopper, or railcar).

Loader (also known as: bucket loader, front loader, front end loader, payloader, scoop loader, shovel, skip loader, and/or wheel loader) is a type of tractor, usually wheeled, sometimes on tracks, that has a front mounted square wide bucket connected to the end of two booms (arms) to scoop up loose material from the ground, such as dirt, sand or gravel, and move it from one place to another without pushing the material across the ground. A loader is commonly used to move a stockpiled material from ground level and deposit it into an awaiting dump truck or into an open trench excavation.

Loaders are used mainly for uploading materials into trucks, laying pipe, clearing rubble, and digging. A loader is not the most efficient machine for digging as it cannot dig very deep below the level of its wheels, like a backhoe can. The capacity of a loader bucket can be anywhere from 0.5 to 36 m³ [1] depending upon the size of the machine and its application. The front loader's bucket capacity is generally much bigger than a bucket capacity of a backhoe loader.

Unlike most bulldozers, most loaders are wheeled and not tracked, although track loaders are common. They are successful where sharp edged materials in construction debris would damage rubber wheels, or where the ground is soft and muddy. Wheels provide better mobility and speed and do not damage paved roads as much as tracks, but provide less traction.

In construction areas loaders are also used to transport building materials - such as bricks, pipe, metal bars, and digging tools - over short distances.

Front loaders are commonly used to remove snow especially from sidewalks, parking lots, and other areas too small for using snowplows and other heavy equipment.

Bac khoe

backhoe, also called a rear actor or back actor, is a piece of

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excavating equipment or digger consisting of a digging bucket on the end of a two-part articulated arm. They are typically mounted on the back of a tractor or front loader. The section of the arm closest to the vehicle is known as the boom, and the section which carries the bucket is known as the dipper or dipperstick (the terms "boom" and "dipper" having been used previously on steam shovels). The boom is attached to the vehicle through a pivot known as the kingpost, which allows the arm to slew left and right, usually through a total of around 200 degrees. Modern backhoes are powered by hydraulics.

Most backhoes are at their strongest curling the bucket, with the dipper arm next most powerful, and boom movements the least powerful.

A backhoe loader is a tractor-like vehicle with an arm and bucket mounted on the back and a front loader mounted on the front. This type of vehicle is often known colloquially as a JCB in Europe (after its inventor) and simply a Backhoe or a Tractor Loader Backhoe (TLB) in North America. In North American terms, a Backhoe includes both a front bucket and a rear hoe, on a chassis originally derived from farm tractors. A dedicated hoe on its own chassis is more properly referred to as an excavator.

Backhoes can be designed and manufactured from the start as such, or can be the result of a farm tractor equipped with a Front End Loader (FEL) and rear hoe. Though similar looking, the designed backhoes are much stronger, with the farm variation more suitable for light work. The farm variation also requires that the operator switch seats from sitting in front of the backhoe controls to the tractor seat in order to reposition the equipment while digging, and this often slows down the digging process.

Backhoes are general purpose tools, and are being displaced to some extent by multiple specialist tools like the excavator and the speciality Front End Loader, especially with the rise of the mini-excavator. On many jobsites which would have previously seen a backhoe used, a skidsteer (colloquially often called a Bobcat after the most well known manufacturer and inventor of the category) and a mini excavator will be used in conjunction to fill the backhoe's role. However, backhoes still are in general use.

Clam Shell

Clam Shell is an excavator with a function as pengeduk flops. What distinguishes the Back Hoe is on bucketnya, a bucket at the Clam Shell sepertihalnya crab claw like pincers.

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Scrapper

Scrapper is a kind of tractor with a blade at the center and have a bucket or container to hold the material you want to move a particular capacity, Scrapper serves to peel soil material and the material is then inserted in a bucket or container in the Scrapper is a closed or can be regarded as heavy equipment wheels tires (tire) that is usually used to load / transport and dispose of (spreading) in individuals with or without assisted driving (bulldozers).

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Dragline

dragline excavator is a piece of heavy equipment used in civil engineering and surface mining.

In civil engineering the smaller types are used for road, port construction, and as pile driving rigs. The larger types are used in strip-mining operations to move overburden above coal, and for tar-sand mining. Draglines are amongst the largest mobile equipment ever built on land, and weigh in the vicinity of 2000 metric tonnes, though specimens weighing up to 13,000 metric tonnes have also been constructed.

A dragline bucket system consists of a large bucket which is suspended from a boom (a large truss-like structure) with wire ropes. The bucket is manoeuvred by means of a number of ropes and chains. The hoist rope, powered by large diesel or electric motors, supports the bucket and hoist-coupler assembly from the boom. The dragrope is used to draw the bucket assembly horizontally. By skillful manoeuvre of the hoist and the dragropes the bucket is controlled for various operations. A schematic of a large dragline bucket system is shown below.

In a typical cycle of excavation, the bucket is positioned above the material to be excavated. The bucket is then lowered and the dragrope is then drawn so that the bucket is dragged along the surface of the material. The bucket is then lifted by using the hoist rope. A swing operation is then performed to move the bucket to the place where the material is to be dumped. The dragrope is then released causing the bucket to tilt and empty. This is called a dump operation.

The bucket can also be 'thrown' by winding up to the jib and then releasing a clutch on the drag cable. This would then swing the bucket like a pendulum. Once the bucket had passed the vertical, the hoist cable would be released thus throwing the bucket. On smaller draglines, a skilled operator could make the bucket land about one-half the length of the jib further away than if it had just been dropped. On larger draglines, only a few extra metres may be reached.

Draglines have different cutting sequences. The first is the side cast method using offset benches; this involves throwing the overburden sideways onto blasted material to make a bench. The second is a key pass. This pass cuts a key at the toe of the new highwall and also

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shifts the bench further towards the low-wall. This may also require a chop pass if the wall is blocky.

Mobile Crane

Mobile Crane A cable-controlled crane mounted on crawlers or rubber-tired carriers. A hydraulic-powered crane with a telescoping boom mounted on truck-type carriers or as self-propelled models.

A truck carrier provides the mobility for this type of crane. This crane has two parts: there carrier, often referred to as the Lower, and the lifting component which includes the boom, referred to as the Upper. These are mated together through a turntable allowing the upper to swing from side to side. These modern hydraulic truck cranes are usually single-engine machines, with the same engine powering the undercarriage and the crane. the upper is usually powered via hydraulics run through the

turntable from the pump mounted on the lower. In older model designs of hydraulic truck cranes there were 2 engines. One in the lower pulled the crane down the road and ran a hydraulic pump for the outriggers and jacks. The one in the upper ran the upper through a hydraulic pump of it's own. Many older operaters favor the 2 engine system due to leaking seals in the turntable of aging newer design cranes.

Generally, these cranes are able to travel on highways, eliminating the need for special equipment to transport the crane unless weight or other size constrictions are in place such as local laws. If this is the case most larger cranes are equipped with either special trailers to help spread the load over more axles or are able to disassemble to meet requirements. An example is counterweights. Often a crane will be followed by another truck hauling the counterweights that are removed for travel. In addition some cranes are able to remove the entire upper. However, this is usually only an issue in a large crane and mostly done with a conventional crane such as a link-belt HC-238. When working on the jobsite, outriggers are extended horizontally from the chassis then vertically to level and stabilize the crane while stationary and hoisting. Many truck cranes have slow-travelling capability (a few miles per hour) while suspending a load. Great care must be taken not to swing the load sideways from the direction of travel, as most anti-tipping stability then lies in the stiffness of the chassis suspension. Most cranes of this type also have moving counterweights for stabilization beyond that provided by the outriggers. Loads suspended directly aft are the most stable, since most of the weight of the crane acts as a counterweight. Factory-calculated charts (or electronic safeguards) are used by crane operators to determine the maximum safe loads for stationary (outriggered) work as well as (on-rubber) loads and travelling speeds.

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Truck cranes range in lifting capacity from about 14.5 short tons (12.9 long tons; 13.2 t) to about 1,300 short tons (1,161 long tons; 1,179 t.

Dump Truck

Dump truck (or, UK, dumper truck) is a truck used for transporting loose material (such as sand, gravel, or dirt) for construction. A typical dump truck is equipped with a hydraulically operated open-box bed hinged at the rear, the front of which can be lifted up to allow the contents to be deposited on the ground behind the truck at the site of delivery. In the UK and Australia the term applies to off-road construction plant only, and the road vehicle is known as a tipper, tipper lorry (UK) or tip truck (AU). standard dump truck is a truck chassis with a dump body mounted to the frame. The bed is raised by a hydraulic ram mounted under the front of the dumper body between the frames, and the back of the bed is hinged at the back to the truck. The tailgate can be configured to swing on hinges or it can be configured in the "High Lift Tailgate" format wherein pneumatic rams lift the gate open and up above the dump body.

In the United States, a standard dump truck has one front axle, and one or more rear axles which typically have dual wheels on each side. Rear axles are either powered or unpowered. Most unpowered rear axles can be raised off the pavement, to minimize wear and tear when the truck is unloaded or lightly loaded, and lowered to become load-bearing when the truck needs the extra support. These are referred to as lift axles or drop axles. Lift axles can be steerable or non-steerable; steerable lift axles are always configured with single wheels on each side, instead of dual wheels. Lift axles positioned in front of the powered axles are called pushers; lift axles positioned behind the powered axles are called tags. A trailing tag is a special type of tag mounted on an arm that extends 12 to 15 ft (3.66 to 4.57 m) behind the truck frame to extend the overall outer bridge length of the vehicle.

Common configurations for a standard dump truck include the six wheeler which has one powered rear axle, the ten wheeler with two powered rear axles, the tri-axle with one lift axle and two powered axles, and the quad with two lift axles and two powered axles.. The largest of the standard dump trucks is commonly called a "centipede" and has seven axles. The rear two axles are powered, the front axle is the steering axle, and the remaining four are lift axles. The intermediate axles are present to support the weigh over the length of the chassis and sometimes to provide additional braking power. In the European Union, the

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dump truck configurations are 2, 3 and 4 axles. The 4 axle eight wheeler has 2 axles at the front and 2 at the rear[notes 1] and is limited to 32 metric tons (35 short tons; 31 long tons) gross weight in most EU countries.

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Trailer

semi-trailer does not trail completely behind the towing vehicle, but is attached at a point that is just forward of the rear-most axle of the towing unit, so that some fraction of the weight of the trailer is carried by the prime mover, with most of that at the rear axle of the prime mover, but a small amount at the front axle. This arrangement requires both tractor and semi-trailer to be distinct in design from a rigid truck and trailer.

In North America, semi tractors usually have 3 axles, the front, or "steer", axle having two wheels, and each of the two rear, "drive", axles having a pair of "dualies" (double wheels) on each side. Thus, the most common configuration of tractor has 10 wheels; however, in some cases dual wheels are replaced by tires known as "super singles" (see below), or wide-base singles, to reduce the weight of the tractor. (The weight reduction is about 180 pounds (82 kg) per axle when using super singles). In this case the tractor will only have six wheels. A smaller tractor, having a single drive axle (six wheeler) is often used to pull shorter trailers in tight urban environments, such as downtown areas where a 60-foot (18 m) rig would be too difficult to maneuver. Sleeper cabs (trucks with sleeper units) usually don't have single axles, but both day cabs and trucks with sleepers are produced with them.

The cargo trailer usually has two "tandem" axles at the rear, each of which has dual wheels, or eight wheels on the trailer. Many trailers are equipped with movable tandems and fifth wheels that can be set to adjust the weight on each axle to stay within legal limits.

Although the sum of the weights of the tractor and the trailer (the gross weight) is normally limited to a certain amount, some roads are marked with a different gross restriction to prevent road damage. Cargoes that exceed allowed weights are usually marked with overweight load and must obtain a permit to use certain roads.

In most areas a truck is generally limited to two trailers and a total length of 26 metres (85 ft) and in urban areas this length limit is further reduced to 19 metres (62 ft). 25 or 26 metre - with permits from state authorities - (82 ft to 85 ft), 62.5 ton (137,788 lb) B-doubles are very common in all parts of Australia including state capitals and on major routes may outnumber single trailer configurations.

Although dual wheels are most common, use of two single, wider tires (known as "super singles") on each axle is becoming popular, initially among bulk cargo carriers and other weight-sensitive operators. With a growing desire to reduce greenhouse gas emissions the use of the super single tire is gaining popularity.

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Tridum Roller

Road rollers use the weight of the vehicle to compress the surface being rolled (static) or use mechanical advantage (vibrating). Initial compaction of the substrate on a road project is done using a padfoot drum roller, which achieves higher compaction density due to the pads having less surface area. On large freeways a four wheel compactor with padfoot drum and a blade, such as a Caterpillar 815/825 series machine, would be used due to its high weight, speed and the powerful pushing force to spread bulk material. On regional roads a smaller single padfoot drum machine may be used. The next machine is usually a single smooth drum compactor that compacts the high spots down until the soil is smooth, and this is usually done in combination with a motor grader to get a level surface. Sometimes at this stage a pneumatic tyre roller would be used. These rollers feature two rows (front and back) of pneumatic tyres that overlap, and the flexibility of the tyres provides a kneading action that seals the surface and with some vertical movement of the wheels, enables the roller to operate effectively on uneven ground. Once the soil base is flat the pad drum compactor is no longer used on the road surface.

The next course (road base) would be compacted using a smooth single drum, smooth tandem roller or pneumatic tyre roller in combination with a grader ,and a water truck to achieve the desired flat surface with the right moisture content for optimum compaction. Once the road base is compacted, the smooth single drum compactor is no longer used on the road surface (There is however an exception, if the single drum has special flat-wide-base tyres on the machine). The final wear course of asphalt concrete (a.k.a. asphalt or blacktop in North America, or macadam in England) is laid using a paver and compacted using a tandem smooth drum roller, a three-point roller or a pneumatic tyre roller. Three point rollers on asphalt were very common once and are still used, but tandem vibrating rollers are the usual choice now, with the pneumatic tyre roller's kneading action being the last roller to seal of the surface.

Rollers are also used in landfill compaction. Such compactors typically have padfoot or "sheep's-foot" drums, and do not achieve a smooth surface. The pads aid in compression, due to the smaller area contacting the ground.

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Double Drum Roller

Tandem Roller: comprises the pivot 2 (two axles) and pivot 3 (three-axle tandem rollers). The use of the roller is generally to obtain a rather smooth surface, such as the rolling of asphalt concrete and others. Tandem roller provides the same path on each wheel, weighing between 8-14 tons, weight gain caused by fluid filling (ballasting) ranged between 25% - 60% of the weight roller. To obtain additional density is usually used on the job rolling three axle tandem roller. Tandem roller should not be used to crush rocks are hard and sharp as it will damage the wheels penggilasnya.

bulldozers are large and powerful tracked heavy equipment. The tracks give them excellent ground hold and mobility through very rough terrain. Wide tracks help distribute the bulldozer's weight over a large area (decreasing pressure), thus preventing it from sinking in sandy or muddy ground. Extra wide tracks are known as 'swamp tracks'. Bulldozers have excellent ground hold and a torque divider designed to convert the engine's power into improved dragging ability. The Caterpillar D9, for example, can easily tow tanks that weigh more than 70 tons. Because of these attributes, bulldozers are used to clear areas of obstacles, shrubbery, burnt vehicles, and remains of structures.

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PNEUMATIC-TIRED ROLLERS

The pneumatic-tired rollers are widely used for compaction of subgrades, bases, bituminous mixes, and many types of material. They have rubber tires instead of steel tires or drums and generally feature two tandem axles, with three or four tires on the front axle and four or five tires on the rear, as shown in figure 11-42. They are aligned so the rear tires cover the spaces left between the tracks of the front tires. The tires are mounted in pairs that can oscillate, or singly with spring action, so tires can move down into soft spots that would be bridged by a steel drum.

The rubber tires add to their downward pressure a kneading effect, as material is pressed toward spaces between the tires. Pneumatic-tired rollers can be ballasted to adjust the weight. Depending on size and type, the weight may vary from 10 to 35 tons. However, more important than gross weight is the weight per wheel for the material being compacted. Figure 11-43.—Action of a pneumatic-tired roller. CAUTION Pneumatic rollers ballast with water are top heavy and are very unstable when operating on uneven terrain

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Dredger

Dredging is an excavation activity or operation usually carried out at least partly underwater, in shallow seas or fresh water areas with the purpose of gathering up bottom sediments and disposing of them at a different location. This technique is often used to keep waterways navigable.

It is also used as a way to replenish sand on some public beaches, where too much sand has been lost because of coastal erosion. Dredging is also used as a technique for fishing for certain species of edible clams and crabs, see fishing dredge.

A dredge is a device for scraping or sucking the seabed, used for dredging. A dredger is a ship or boat equipped with a dredge. The terms are sometimes interchanged.

The process of dredging creates spoils (excess material), which are carried away from the dredged area. Dredging can produce materials for land reclamation or other purposes (usually construction-related), and has also historically played a significant role in gold mining. Dredging can create disturbance in aquatic ecosystems, often with adverse impacts.

Capital: dredging carried out to create a new harbour, berth or waterway, or to deepen existing facilities in order to allow larger ships access. Because capital works usually involve hard material or high-volume works, the work is usually done using a cutter suction dredge or large trailing suction hopper dredge, but for rock works drilling and blasting along with mechanical excavation may be used.

Preparatory: work and excavation for future bridges, piers or docks/wharves, often connected with foundation work.

Maintenance: dredging to deepen or maintain navigable waterways or channels which are threatened to become silted with the passage of time, due to sedimented sand and mud, possibly making them too shallow for navigation. This is often carried out with a trailing suction hopper dredge. Most dredging is for this purpose, and it may also be done to maintain the holding capacity of reservoirs or lakes.

Land reclamation: dredging to mine sand, clay or rock from the seabed and using it to construct new land elsewhere. This is typically performed by a cutter-suction dredge or trailing suction hopper dredge. The material may also be used for flood or erosion control.

Beach nourishment: mining sand offshore and placing on a beach to replace sand eroded by storms or wave action. This is done to enhance the recreational and protective function of the beaches, which can be eroded by human activity or by storms. This is typically performed by a cutter-suction dredge or trailing suction hopper dredge.

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Tower Crane

crane is a type of machine, generally equipped with a hoist, wire ropes or chains, and sheaves, that can be used both to lift and lower materials and to move them horizontally. It uses one or more simple machines to create mechanical advantage and thus move loads beyond the normal capability of a man. Cranes are commonly employed in the transport industry for the loading and unloading of freight, in the construction industry for the movement of materials and in the manufacturing industry for the assembling of heavy equipment.

ower cranes are a modern form of balance crane that consist of the same basic parts. Fixed to the ground on a concrete slab (and sometimes attached to the sides of structures as well), tower cranes often give the best combination of height and lifting capacity and are used in the construction of tall buildings. The base is then attached to the mast which gives the crane its height. Further the mast is attached to the slewing unit (gear and motor) that allows the crane to rotate. On top of the slewing unit there are three main parts which are: the long horizontal jib (working arm), shorter counter-jib, and the operators cab.

The long horizontal jib is the part of the crane that carries the load. The counter-jib carries a counterweight, usually of concrete blocks, while the jib suspends the load to and from the center of the crane. The crane operator either sits in a cab at the top of the tower or controls the crane by radio remote control from the ground. In the first case the operator's cab is most usually located at the top of the tower attached to the turntable, but can be mounted on the jib, or partway down the tower. The lifting hook is operated by the crane operator using electric motors to manipulate wire rope cables through a system of sheaves. The hook is located on the long horizontal arm to lift the load which also contains its motor.A tower crane rotates on its axis before lowering the lifting hook.

In order to hook and unhook the loads, the operator usually works in conjunction with a signaller (known as a 'dogger', 'rigger' or 'swamper'). They are most often in radio contact, and always use hand signals. The rigger or dogger directs the schedule of lifts for the crane, and is responsible for the safety of the rigging and loads.

A tower crane is usually assembled by a telescopic jib (mobile) crane of greater reach (also see "self-erecting crane" below) and in the case of tower cranes that have risen while constructing very tall skyscrapers, a smaller crane (or derrick) will often be lifted to the roof of the completed tower to dismantle the tower crane afterwards, which may be more difficult than the installation

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Stone Crusher

crusher is a machine designed to reduce large rocks into smaller rocks, gravel, or rock dust. Crushers may be used to reduce the size, or change the form, of waste materials so they can be more easily disposed of or recycled, or to reduce the size of a solid mix of raw materials (as in rock ore), so that pieces of different composition can be differentiated. Crushing is the process of transferring a force amplified by mechanical advantage through a material made of molecules that bond together more strongly, and resist deformation more, than those in the material being crushed do. Crushing devices hold material between two parallel or tangent solid surfaces, and apply sufficient force to bring the surfaces together to generate enough energy within the material being crushed so that its molecules separate from (fracturing), or change alignment in relation to (deformation), each other. The earliest crushers were hand-held stones, where the weight of the stone provided a boost to muscle power, used against a stone anvil. Querns and mortars are types of these crushing devices.

crushers are machines which use a metal surface to break or compress materials. Mining operations use crushers, commonly classified by the degree to which they fragment the starting material, with primary and secondary crushers handling coarse materials, and tertiary and quaternary crushers reducing ore particles to finer gradations. Each crusher is designed to work with a certain maximum size of raw material, and often delivers its output to a screening machine which sorts and directs the product for further processing. Typically, crushing stages are followed by milling stages if the materials need to be further reduced. Crushers are used to reduce particle size enough so that the material can be processed into finer particles in a grinder. A typical circuit at a mine might consist of a crusher followed by a SAG mill followed by a ball mill. In this context, the SAG mill and ball mill are considered grinders rather than crushers.

In operation, the raw material (of various sizes) is usually delivered to the primary crusher's hopper by dump trucks, excavators or wheeled front-end loaders. A feeder device such as an apron feeder, conveyor or vibrating grid controls the rate at which this material enters the crusher, and often contains a preliminary screening device which allows smaller material to bypass the crusher itself, thus improving efficiency. Primary crushing reduces the large pieces to a size which can be handled by the downstream machinery.

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Sheep Foot Roller Pounder type of leg of lamb, the principle of sheep foot roller is a cylinder mounted on the outside legs. On the legs is the case of high pressure, so that these legs into the ground and give the effect of "solidification from below". Sheep foot roller is best used for sandy soils with little clay containing, also for plastic and cohesive soils. Very effectively used for compacting loose material with a layer thickness between 15-25 cm. In addition to the pull of sheep foot roller (towed) also found that sheep foot roller engine that can move itself at speeds of about 32 km / hour. For the sheep foot roller-drawn, if the force is large enough tractor pullers, usually drawn some distance, lined to the side, one line or a combination of both. Sheep foot roller size is between 3-5 tons, but some are 12-30 tons.

Some bulldozers have been fitted with armor by non-government civilian operators to prevent

bystanders or police from interfering with the work performed by the bulldozer, as in the case

of strikes or demolition of condemned buildings. This has also been done by civilians with a

dispute with the authorities, such as Marvin Heemeyer, who outfitted his Komatsu D355A

bulldozer with homemade composite armor to then demolish government buildings.

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