Road Making Machines in Mines

Materials collected for classroom discussion and academic use only

Definition of Pavement Systems

• 100% coverage under the wheel

• Contact pressure up to 380 kPa

• Can be used on all soil types except for rocky soils.

• Compactive effort: static weight

• The most common use of large smooth wheel rollers isfor proof-rolling subgrades and compacting asphaltpavement.

• 80% coverage under the wheel

• Contact pressure up to 700 kPa

• Can be used for both granular and fine-grainedsoils.

• Compactive effort: static weight and kneading.

• Can be used for highway fills or earth damconstruction.

Pneumatic (or rubber-tired) roller

Smooth-wheel roller (drum)

Sheepsfoot rollers

• Has many round or rectangular shaped protrusions or “feet”attached to a steel drum

• 8% ~ 12 % coverage

• Contact pressure is from 1400 to 7000 kPa

• It is best suited for clayed soils.

• Compactive effort: static weight and kneading.

Tamping foot roller

• About 40% coverage

• Contact pressure is from 1400 to 8400 kPa

• It is best for compacting fine-grained soils (siltand clay).

• Compactive effort: static weight and kneading.

Mesh (or grid pattern) roller

• 50% coverage

• Contact pressure is from 1400 to 6200 kPa

• It is ideally suited for compacting rocky soils,gravels, and sands. With high towing speed, thematerial is vibrated, crushed, and impacted.

• Compactive effort: static weight and vibration.

Vibrating drum on smooth-wheel roller

• Vertical vibrator attached to smooth wheelrollers.

• The best explanation of why roller vibrationcauses densification of granular soils is thatparticle rearrangement occurs due to cyclicdeformation of the soil produced by theoscillations of the roller.

• Compactive effort: static weight and vibration.

• Suitable for granular soils

Features • The CV550 Series of Vibratory Soil Compactor is designed with track drive, which

enables these machines to conquer steep slope applications while compacting. • The machines provide a cost-effective means of compacting jobs like landfill

construction which in the past had to be handled by a vibratory compactor winched up the slope by dozer, thus necessitating the added expense of the dozer its operator.

• Wide variation of drum types; Smooth drum or padfoot drum with standard vibration mode (single eccentric type) or vertical vibration mode (twin eccentriic type) are available to select from Standard vibration models: CV550D (smooth drum), CV550T (padfoot drum) and Vertical vibration model; CV550DV (smooth drum).

• The CV550 Series is able to climb slopes up to 62% (32deg.) while developing the centrifugal forces required to reach density in a minimal number of passes over material.

• This concept also speed compaction of steep embankments, earthen dams and any application where slopes and / or traction may be a problem.

MOTOR GRADER

http://youtu.be/kZMWZwKy4z8

http://youtu.be/PPkr0_-exU8

A 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.

The grader is a long tractor-driven machine with a blade mounted underneath which can be lifted an lowered with a hydraulic system.

The functions of motor grader in making roads or leveling site are:a. Cuttingb. Liftingc. Grading

The main operating unit of the grader is the blade with renewable bottom and end cutting edges. The blade is having capability for the following movements:

• Up and down movement• Sideways movement• Rotational motion.

TYPES• Self powered grader• Mechanically controlled• Hydraulically controlled

Source: http://www.fao.org/docrep/f3200e/f3200e13.gif

Normally, it is a four wheel drive self propelling unit having the following main constructional components: Blade and circle: For grading of surface Transmission: For providing power from the engine to all functional elements Steering system: to steer the grader on travelling Blade control unit: for raising lowering and tilting of the blade Brake system: to control all the operating systems both parking and service brake.

1: Ripper2, 5: Hydraulic Cylinder3, 12: Propeller shaft4: Main frame6: Steering wheel shaft7: Cab8: Engine9: Radiator10: Rear Axle11: Clutch13: Gear Box14: Blade15: Slewing circle16: Slewing circle frame17: Front axle pivot18: Front axle

MOLDBOARDMotor graders are equipped with a moveable blade known as a moldboard. In general, standard moldboardsrange from 10 to 16 feet (3 to 4.9 m), but can be up to 24 feet (7.3 m) wide.[

Different sized moldboards are often required depending on the job. The largest-ever blade was manufactured byACCO in 1980 and is no longer in production – it was 33 feet (10 m) wide.Moldboards are normally mounted to the grader in a circle-mounted configuration. The moldboard is attachedunder the grader’s frame with a ring that can be swiveled vertically to adjust the casting angle of the blade. Byadjusting this way, the grader is able to work sideways, enabling it to do jobs such as pulling ditches and slopingbanks. The motor grader’s front wheels can be tilted up to 20 degrees so as to balance the machine horizontallywhen the moldboard is working at a vertical angle.

http://www.ritchiewiki.com/wiki/index.php/Motor_grader

FRAME:Each motor grader has one of two types of frames: rigid, or articulated. While most new models are comprised ofarticulated frames, some manufacturers have not upgraded the rigid models that were common in the 1980s and1990s; however, relatively few rigid models are available in North America today. An articulated frame is beneficial asit provides great maneuverability and versatility on a wider range of jobs than a rigid-framed motor grader.

Articulation Joints There are two main types of articulated motor graders: those with the articulation joint in front of the cab, and those with the articulation joint behind the cab. Arguably, the “behind the cab” configuration enables the grader operator to have better visibility and a clearer view of the moldboard. An example of a grader with the articulation joint behind the cab is the Champion grader. This machine, unlike other models, carries its transmission ahead of the joint, adding weight and additional power to the moldboard. John Deere graders have the articulation joint in front of the cab. The manufacturers argue that this permits the grader operator to know where the front half of the grader is in relation to the back.

Models whose joints are behind the cab must indicate this with a special monitor.

Transmissions Motor graders today use one of three types of transmissions: hydrostatic, direct-drive, and torque-converter-drive.[28] While large machines generally use direct-drive or torque-converter-drive, smaller machines tend to be hydrostatically driven. This means that a pump, whose flow is moderated with control valves and tubing, feeds a hydraulic motor to produce continuous power.

• The blade is used to push dirt to the front or to the side at a desired level. Though this machine can do light excavation, its main purpose is to prepare level surface.

• The circle or ring to which the blade is attached underneath can be swiveled vertically and the thereby the casting angle of the blade can be adjusted.

• The blade can be angled to shape road banks. Different sizes of blades and machines with different speeds are available from various manufacturers.

• Front tires are usually leaning to resist the force created when the blade is cutting and side casting the material.

• Modern graders are available with laser reader so that the operator can adjust grader depth and obtain desired level.

• The grader productivity depends on the grading speed, grading width, operating factors and number of passes required to cover the area to be graded.

Operations

A motor grader is deployed in a surface mine for profiling job. It is working on 3 shifts per day and the utilisation factor is 90%The geometric volume of the soil moved per working pass is 45 cubic meter and cycle time is 0.25 hour. The loosening factor for the site 0.85. Determine the volume cut by the motorgraderper shift.

The volume cut per shift is calculated as:Qsh = (T.Ku.V)/(t.Kr)where,Qsh: volume cut per shift, m3/shiftT: Shift duration, hr.Ku: Utilisation factorV; geometric volume of material moved per working pass, m3t: Cycle time, hrKr: site loosening factorThus from the given data,Qsh = (8x0.9x45)/(0.25x0.85)= 1524.7 m3/shift

Hazards

Roll over

Struck by hazards Hitting unknown objects Surveying going on in the surrounding area Pinch points Slips and falls

Source: http://www.contractjournal.com/blogs/digger-blog/assets_c/2009/06/Picture%20002-thumb-439x329-37661.jpg

Actual Cases

• At approximately 1:25 p.m. on May 28, 1991, employee #1 was walking behind the rear of a road grader that was backing up. The reverse alarm was sounding and was audible, according to witnesses. Suddenly the employee was caught on her left side by the left rear wheel of the grader and pulled under both tires. Employee #1 sustained injuries to her body including head, leg, and abdominal injuries which led to her death.

Source: Extracted from OSHA Accident Investigation Data 1990-2007

Actual Cases

• Employee #1 had started his galion road grader and left it idling in gear to let the engine and transmission oils warm up. While the machine was idling, he started to climb down from the machine. As he did this he apparently slipped and hit the accelerator pedal, causing the engine to speed up. As the machine started forward, employee #1 fell in front of the left front rear wheel and was run over. He suffered massive internal injuries and was pronounced dead.

Source: Extracted from OSHA Accident Investigation Data 1990-2007

Actual Cases

• The operator prepared to begin backing up the grader. Because the grader was missing the factory installed side rearview mirrors, he looked to the rear over his shoulders. He did not see anyone and backed up the grader. Employee #1 moved into the path of the grader from the right, and the left rear tires struck him and then ran over him. The grader's left side raised up and, when it leveled out, the operator stopped the grader, looked down to the left under the cab steps, and saw employee #1 prone on the ground in front of the left rear tires. Employee #1 suffered multiple injuries to the chest and abdomen. He died.

Source: Extracted from OSHA Accident Investigation Data 1990-2007

Actual Cases

• Employee #1 was using a hand-held optic grade checking device while the coworker was operating a 14 g caterpillar road grader. Employee #1 bent over, placing his head close to the ground to sight an elevation marker located on the side of the new road. At the same time, the coworker backed up the road grader to make another pass over the road fill that had recently been placed there. As he backed up, he ran over and crushed employee #1's head, killing him. The back-up alarm was inoperative.

Source: Extracted from OSHA Accident Investigation Data 1990-2007

Actual Cases

• Employee #1 was directing a road grader on how much grade to cut. After the road grader passed him, he attempted to cross behind it. But the road grader backed up and ran over him. Employee #1 died later in the day from internal injuries.

Source: Extracted from OSHA Accident Investigation Data 1990-2007

OSHA Regulations

• 1926.1001(a)-General. This section prescribes minimum performance criteria for rollover protective structures (ROPS) for rubber-tired self-propelled scrapers; rubber-tired front-end loaders and rubber-tired dozers; crawler tractors, and crawler-type loaders, and motor graders. The vehicle and ROPS as a system shall have the structural characteristics prescribed in paragraph (f) of this section for each type of machine described in this paragraph.

Source: 29 CFR 1926 OSHA Construction Industry Regulations

OSHA Regulations

• 1926.1001(b)-For motor graders: Operating between 0 and 10 miles per hour over hard clay where rollover would be limited to 360 deg. down a slope of 30 deg. maximum.

• 1926.1001(c)(1)(iii)-Recommended, but not mandatory, types of test setups are illustrated in Figure W-1 for all types of equipment to which this section applies; and in Figure W-2 for rubber-tired self-propelled scrapers; Figure W-3 for rubber-tired front-end loaders, rubber-tired dozers, and motor graders; and Figure W-4 for crawler tractors and crawler-type loaders.

Source: 29 CFR 1926 OSHA Construction Industry Regulations

OSHA Regulations

• 1926.1001(f)(2)(i)- The energy requirement for purposes of meeting the requirements of paragraph (e)(1) of this section is to be determined by referring to the plot of the energy versus weight of vehicle (see Figure W-6 for rubber-tired self-propelled scrapers; Figure W-7 for rubber-tired front-end loaders and rubber-tired dozers; Figure W-8 for crawler tractors and crawler-type loaders; and Figure W-9 for motor graders). For purposes of this section, force and weight are measured as pounds (lb.); energy (U) is measured as inch-pounds.

Source: 29 CFR 1926 OSHA Construction Industry Regulations

OSHA Regulations

• 1926.1001(f)(2)(ii)-The applied load must attain at least a value which is determined by multiplying the vehicle weight by the corresponding factor shown in Figure W-10 for rubber-tired self-propelled scrapers; in Figure W-11 for rubber-tired front-end loaders and rubber-tired dozers; in Figure W-12 for crawler tractors and crawler-type loaders; and in Figure W-13 for motor graders.

Source: 29 CFR 1926 OSHA Construction Industry Regulations

Best Practices

• PPE- foot protection, hi-visibility vest, hard hat, eye protection, and hand gloves.

• Always maintain 3 points of body contact when entering or leaving cabin.

• Check condition of, and adjust mirrors to provide good rear and side vision.

• Check terrain and area being graded for rocks, stumps or other obstacles that could cause machine to stop suddenly when grading or ripping.

Source: http://www.mitchellshire.vic.gov.au/Files/Motor_Grader%5B1%5D_28Aug09.pdf

Best Practices

• Perform a walk-around before beginning work with the equipment.

• Use flashing light to warn others of presence when operating in vicinity of other machinery, persons, or in close proximity to traffic on roadways, etc.

• Ensure that all safeguards and covers are fitted correctly and closed.

Source: http://www.mitchellshire.vic.gov.au/Files/Motor_Grader%5B1%5D_28Aug09.pdf

Design with Safety: M-series of Caterpillar graderOperator Safety

Advanced Joystick Controls - Two electro-hydraulic joysticks reduce hand and wrist movement as much as 78% compared to conventional lever controls for greatly enhanced operator efficiency.

Auxiliary Pod and Ripper Control for the 140M (Optional) - The optional ripper control and auxiliary control pod are ergonomically positioned to allow simple, comfortable operation for the multiple hydraulic options.

Visibility - The exceptional forward view is made possible by a unique raised cab design, elimination of the steering wheel and controls from in front of the operator, and a one-piece front window. The result is improved operator confidence and productivity. The large side windows offer a clear view of the moldboard heel and tandem tires. A wide rear window provides good visibility behind the machine. Glare reducing paint on the front frame, lift arms and rear enclosure help reduce glare, resulting in safer operation at night.

In-Dash Instrument Cluster - The instrument panel, with easy-to read, high-visibility gauges and warning lamps, keeps the operator aware of critical system information.

Controls and Switches - Reliable, long life rocker switches are located on the right side cab post and front instrument cluster, within easy reach for the operator. Controls and switches are backlit for increased safety during night time operations.

Operator Seat - The Cat Comfort Series air suspension seat has an ergonomic high-back design, with extra thick contoured cushions and infinitely adjustable lumbar support that evenly distributes the operator’s weight. Multiple seat controls and armrests are easy to adjust for optimal support and comfort all day.

Low Interior Sound and Vibration Levels - Isolation mounts for the cab, engine and transmission significantly reduce sound and vibration. The quiet interior with low vibration levels provide a comfortable work environment.

Comfort and Convenience - Caterpillar has built the most comfortable cab in the industry by replacing the control levers and steering wheel with two joystick controls. Extra leg and foot room create a spacious, open cab. Multiple adjustment capabilities for the arm rests, wrist rests and joystick pods help keep the operator comfortable throughout a long shift.

Optional HVAC system for the 140M - The optional heating, ventilation and air conditioning system uses intelligent vent placement for consistent climate control and clear windows for every condition. The high capacity system dehumidifies air and pressurizes the cab, circulating fresh air and sealing out dust. An easily accessible fresh air filter is located outside the cab at ground level for quick replacement or cleaning.

Optional HVAC Precleaner for the 140M - Increases the service interval of the HVAC fresh air filter by up to ten times.

VISIBILITY SAFETY

•Rear Vision Camera with In-Cab Monitor (Optional) - Visibility is further enhanced with an optional

Work Area Vision System (WAVS) through a 178 mm (7 in) LCD color monitor in the cab. Developed

specifically for rugged applications, this durable camera improves productivity and increases operator

awareness of surroundings.

•Windshield Cleaning Platform (Optional) - Provides the operator the ability to clean the windshield

while on the machine without having to go to ground level. See your dealer for availability.

•Drop-Down Rear Lights - Optional dropdown lights fold out from the rear of the machine. This creates

a wider, lower profile to be better aligned with passenger cars.

•High Intensity Discharge (HID) Lights (Optional) - Optional HID lights can replace the standard

halogen lamps. The powerful HID lights are four times brighter, improving night time visibility and safety.

•Heated Mirrors (Optional) - This system keeps the rear-view mirrors clear of ice and snow to facilitate

working in winter conditions.

•Warning Beacon Lights (Optional) - Rotating light beacons are available as an additional safety

feature. This option comes with two beacons placed on diagonal corners of the cab roof so they are

visible from any angle around the machine.

MACHINE SAFETY

•Operator Presence System - The Operator Presence System keeps the parking brake engaged and hydraulic implements

disabled until the operator is seated and the machine is ready for safe operation.

•Secondary Steering System - The standard secondary steering system automatically engages an electric hydraulic pump in case

of a drop in steering pressure, allowing the operator to steer the machine to a safe stop.

•Speed Sensitive Steering - The steering software automatically provides an infinitely variable ratio between the joystick and the

steer tires, resulting in less sensitive steering as the ground speed increases.

•Hydraulic Lockout - A simple switch located in the cab disables all implement functions while still providing machine steering

control. This safety feature is especially useful while the machine is roading.

•Brake Systems - Brakes are located at each tandem wheel to eliminate braking loads on the power train. In addition, the brake

systems are redundant and utilize accumulators to enable stopping in case of machine failure, further increasing operational safety.

•Steel Tandem Walkways - Perforated raised steel walkways cover the tandems. This provides a sturdy slip-resistant platform for

standing and walking, and additional protection for the brake lines.

•ROPS/FOPS Cab - Isolation mounted to the frame to reduce vibration and sound, the integral ROPS/FOPS structure meets ISO

and SAE criteria for operator protection.

•Circle Drive Slip Clutch - This standard feature protects the drawbar, circle and moldboard from shock loads when the blade

encounters an immovable object. It also reduces the possibility of abrupt directional changes in poor traction conditions, protecting

the machine, operator and surroundings.

•Blade Lift Accumulators - This optional feature uses accumulators to help absorb impact loads to the moldboard by allowing

vertical blade travel. Blade lift accumulators reduce unnecessary wear and help to avoid unintended machine movement for

increased operator safety.

•Fenders - To help reduce objects flying from the tires, as well as build-up of mud, snow and debris, optional fenders can be added.

MAINTENANCE SAFETY

•Engine Shutoff Switch - An engine shutoff switch is located at ground level on the left rear of the machine, allowing

anyone nearby to shut it down in case of an emergency.

•Electrical Disconnect Switch - A battery disconnect switch, located inside the left rear enclosure, provides ground-

level lockout of the electrical system to prevent inadvertent starting of the machine.

•Grouped Service Points - The M-Series groups daily service points in the left side service center to help ensure

proper maintenance and inspection routines.

•Ecology Drains - Conveniently located ecology drains shorten service times and help keep the environment safe by

preventing spills.

In a motor vehicle, the term powertrain or powerplant refers to the group of components that generate power and deliver it to the road surface, water, or air. This includes the engine, transmission, driveshafts, differentials, and the final drive (drive wheels, continuous track like with tanks or Caterpillar tractors, propeller, etc.). Sometimes "powertrain" is used to refer to simply the engine and transmission, including the other components only if they are integral to the transmission. In a carriage or wagon, running gear designates the wheels and axles in distinction from the body.A motor vehicle's driveline consists of the parts of the drivetrain excluding the engine and transmission. It is the portion of a vehicle, after the transmission, that changes depending on whether a vehicle is front-wheel drive, rear-wheel drive, four-wheel drive, or the more exotic Six-wheel drive.

The parts of a torque converter (left to right): turbine, stator, pump

Hydraulic power is defined as flow times pressure. The hydraulic power supplied by a pump:

Power = (P x Q) ÷ 600

where power is in kilowatts [kW], P pressure in bars, and Q is the flow in liters per minute. For example, a pump delivers 180

lit/min and the pressure equals 250 bar, therefore the power of the pump is 75 kW.

When calculating the power input to the pump, the total pump efficiency ηtotal must be included. This efficiency is the product of

volumetric efficiency, ηvol and the hydromechanical efficiency, ηhm. Power input = Power output ÷ ηtotal. The average for axial

piston pumps, ηtotal = 0.87. In the example the power source, for example a diesel engine or an electric motor, must be capable

of delivering at least 75 ÷ 0.87 = 86 [kW]. The hydraulic motors and cylinders that the pump supplies with hydraulic power also

have efficiencies and the total system efficiency (without including the pressure drop in the hydraulic pipes and valves) will end

up at approx. 0.75. Cylinders normally have a total efficiency around 0.95 while hydraulic axial piston motors 0.87, the same as

the pump. In general the power loss in a hydraulic energy transmission is thus around 25% or more at ideal viscosity range 25-

35 [cSt].

Calculation of the required max. power output for the diesel engine, rough estimation:

(1) Check the max. powerpoint, i.e. the point where pressure times flow reach the max. value.

(2) Ediesel = (Pmax·Qtot)÷η.

Qtot = calculate with the theoretical pump flow for the consumers not including leakages at max. power point.

Pmax = actual pump pressure at max. power point.

Note: η is the total efficiency = (output mechanical power ÷ input mechanical power). For rough estimations, η = 0.75. Add 10-

20% (depends on the application) to this power value.

(3) Calculate the required pumpdisplacement from required max. sum of flow for the consumers in worst case and the diesel

engine rpm in this point. The max. flow can differ from the flow used for calculation of the diesel engine power. Pump volumetric

efficiency average, piston pumps: ηvol= 0.93.

Pumpdisplacement Vpump= Qtot ÷ ndiesel ÷ 0.93.

(4) Calculation of prel. cooler capacity: Heat dissipation from hydraulic oil tanks, valves, pipes and hydraulic components is less

than a few percent in standard mobile equipment and the cooler capacity must include some margins. Minimum cooler capacity,

Ecooler = 0.25Ediesel

At least 25% of the input power must be dissipated by the cooler when peak power is utilized for long periods. In normal case

however, the peak power is used for only short periods, thus the actual cooler capacity required might be considerably less.

The oil volume in the hydraulic tank is also acting as a heat accumulator when peak power is used. The system efficiency is

very much dependent on the type of hydraulic work tool equipment, the hydraulic pumps and motors used and power input to

the hydraulics may vary a lot. Each circuit must be evaluated and the load cycle estimated. New or modified systems must

always be tested in practical work, covering all possible load cycles. An easy way of measuring the actual average power loss

in the system is to equip the machine with a test cooler and measure the oil temperature at cooler inlet, oil temperature at

cooler outlet and the oil flow through the cooler, when the machine is in normal operating mode. From these figures the test

cooler power dissipation can be calculated and this is equal to the power loss when temperatures are stabilized. From this test

the actual required cooler can be calculated to reach specified oil temperature in the oil tank. One problem can be to assemble

http://en.wikipedia.org/wiki/Hydraulic_machinery