What is a Motor Grader

Motor grader

A motor grader, also commonly referred to as a road grader, a blade, or a maintainer, 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 motor 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.

Motor 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.

 Motor 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, motor graders are often used in municipal and residential snow removal. In scrubland and grassland areas of Australia and Africa, motor 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.

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

What is a Hydraulic excavators

Hydraulic Excavator

Excavators are heavy construction equipment consisting of a boom, bucket and cab on a rotating platform (known as the "house"). The house sits atop an undercarriage with tracks or wheels. All movement and functions of the excavator are accomplished through the use of hydraulic fluid, be it with rams or motors. Their design is a natural progression from the steam shovel.

Usage

Excavators are used in many ways:

• ·         Digging of trenches, holes, foundations
• ·         Material handling
• ·         Brush cutting with hydraulic attachments
• ·         Forestry work
• ·         Demolition
• ·         General grading/landscaping
• ·         Heavy lift, e.g. lifting and placing of pipes
• ·         Mining, especially, but not only open-pit mining
• ·         River dredging
• ·         Driving piles, in conjunction with a Pile Driver

Configurations

Excavators come in a wide variety of sizes. The smaller ones are called mini or compact excavators. Caterpillar's smallest mini-excavator weighs 3,549 pounds (1,610 kg) and has 19 hp; their largest model weighs 187,360 pounds (84,990 kg) and has 513 hp

Engines in excavators drive hydraulic pumps; there are usually 3 pumps: the two main pumps are for supplying oil at high pressure (up to 5000 psi) for the rams, swing motor, track motors, and accessories, and the third is a lower pressure (700 psi) pump for Pilot Control, this circuit used for the control of the spool valves, this allows for a reduced effort required when operating the controls.

The two main sections of an excavator are the undercarriage and the house. The undercarriage includes the blade (if fitted), tracks, track frame, and final drives, which have a hydraulic motor and gearing providing the drive to the individual tracks, and the house includes the operator cab, counterweight, engine, fuel and hydraulic oil tanks. The house attaches to the undercarriage by way of a center pin, allowing the machine to slew 360° unhindered.

The main boom attaches to the house, and can be one of 3 different configurations:

• ·         Most are mono booms: these have no movement apart from straight up and down.
• ·         Some others have a knuckle boom which can also move left and right in line with the machine.
• ·         The other option is a hinge at the base of the boom allowing it to hydraulically pivot up to 180° independent to the house, however this is generally available only to compact excavators.

Attached to the end of the boom is the stick (or dipper arm). The stick provides the digging force needed to pull the bucket through the ground. The stick length is optional depending whether reach (longer stick) or break-out power (shorter stick) is required.

On the end of the stick is usually a bucket. A wide, large capacity (Mud) bucket with a straight cutting edge is used for cleanup and levelling or where the material to be dug is soft, and teeth are not required. A general purpose (GP) bucket is generally smaller, stronger, and has hardened side cutters and teeth used to break through hard ground and rocks. Buckets have numerous shapes and sizes for various applications. There are also many other attachments which are available to be attached to the excavator for boring, ripping, crushing, cutting, lifting, etc.

 Excavator attachments

In recent years, hydraulic excavator capabilities have expanded far beyond excavation tasks with buckets. With the advent of hydraulic powered attachments such as a breaker, a grapple or an auger, the excavator is frequently used in many applications other than excavation. Many excavators feature a quick coupler for simplified attachment mounting, increasing the machine's utilization on the jobsite. Excavators are usually employed together with loaders and bulldozers. Most wheeled, compact and some medium sized (11 to 18 tonne) excavators have a backfill (or dozer) blade. This is a horizontal bulldozer-like blade attached to the undercarriage and is used for levelling & pushing removed material back into a hole.

Compact excavator

A compact or mini excavator is a tracked or wheeled vehicle with an approximate operating weight from 0.7 to 7.5 tones. It generally includes a standard backfill blade and features independent boom swing.

Hydraulic Excavators are somewhat different from other construction equipment in that all movement and functions of the machine are accomplished through the transfer of hydraulic fluid. The compact excavator's work group and blade are activated by hydraulic fluid acting upon hydraulic cylinders. The excavator's slew (rotation) and travel functions are also activated by hydraulic fluid powering hydraulic motors.

Structure

Most compact hydraulic excavators have three distinct assemblies: house, undercarriage and workgroup.

House

The house structure contains the operator's compartment, engine compartment, hydraulic pump and distribution components. The house structure is attached to the top of the undercarriage via a swing bearing. The house, along with the workgroup, is able to rotate or slew upon the undercarriage without limit due to a hydraulic distribution valve which supplies oil to the undercarriage components.

Slew

 Slewing refers to rotating the excavator's house assembly. Unlike a conventional backhoe, the operator can slew the entire house and workgroup upon the undercarriage for spoil placement.

Undercarriage

 The undercarriage consists of rubber or steel tracks, drive sprockets, rollers, idlers and associated components/structures. The undercarriage supports the house structure and the workgroup.

Workgroup

 The workgroup of a compact hydraulic excavator consists of the boom, dipper or arm, and attachment (e.g. auger, bucket or breaker). It is connected to the front of the excavator's house structure via a swing frame that allows the workgroup to be hydraulically pivoted left or right to achieve offset digging for trenching parallel with the tracks.

Backfill blade

 The backfill blade is used for grading, leveling, backfilling, trenching, and general dozer work. The blade can be used to increase dump height and digging depth depending on its position in relation to the excavator's workgroup, this makes it very versatile.

Zero-tail Swing

There are two distinct classes of compact excavators, conventional tail swing - units that have a rear counterweight that will extend beyond the tracks when the house rotates, and zero-tail swing - units with a house whose diameter stays within the width of the tracks through full rotation. Zero-tail swing units allow the operator to focus on digging and not watching where he or she is swinging.

What is a Cold planer

Cold planer

 A cold planer (also known as a pavement planer, pavement recycler, mill or asphalt milling machine or rotomill) is Heavy equipment used to remove bituminous pavement or asphalt concrete from roadways, resulting in a smooth, even surface. This is accomplished by bringing a spinning mandrel or "head" into contact with the pavement at an exact depth or slope. It is normally fed by conveyor into a dump truck, or semi trailer but can be left in place or "wind-rowed" to be removed at a later date or used in reclaiming.

Backhoe 

 A backhoe, also called a rear actor or back actor, is a piece of 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 dipper stick (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.

Characteristics

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.

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.

With the advent of hydraulic powered attachments such as a tilt rotator, breaker, a grapple or an auger, the backhoe is frequently used in many applications other than excavation and with the tilt rotator attachment, serves as an effective tool carrier. Many backhoes feature quick coupler (quick-attach) mounting systems for simplified attachment mounting, dramatically increasing the machine's utilization on the job site. Backhoes are usually employed together with loaders and bulldozers. Excavators that use a backhoe are sometimes called "trackhoes" by people who do not realize the name is due to the action of the bucket, not its location on a backhoe loader.

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 and a mini excavator will be used in conjunction to fill the backhoes role. However, backhoes still are in general use.

What is an Asphalt paver

Asphalt paver 

A paver (paver finisher, asphalt finisher, paving machine) is an engineering vehicle used to lay asphalt on roadways. It is normally fed by a dump truck. A separate machine, a roller, is then used to press the hot asphalt mix, resulting a smooth, even surface. The sub-base being prepared by use of a grader to trim crushed stone to profile after rolling.

What is an Articulated dump truck

Articulated dump truck

A dump 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).

 An articulated dump truck, or Yuke in the construction world, has a hinge between the cab and the dump box, but is distinct from semi trailer trucks in that the cab is a permanent fixture, not a separable vehicle. Steering is accomplished via hydraulic rams that pivot the entire cab, rather than rack and pinion steering on the front axle. This vehicle is highly adaptable to rough terrain. In line with its use in rough terrain, longer distances and overly flat surfaces tend to cause driveline troubles, and failures. Articulated trucks are often referred to as the modern scraper, in the sense that they carry a much higher maintenance burden than most trucks. See the first mass produced articulated dump truck (articulated hauler)