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Maintaining a construction equipment fleet: Efficiency and Organization. (Cover Article).

Efficient construction equipment fleet management consists of several interdependent characteristics that form a cycle. Modern fleet managers must successfully and continuously execute each component of the cycle to assure proper fleet operation.

A well-conceived maintenance management information system can be developed and deployed to serve many vehicle maintenance information needs. But such a system must have a structure or a framework that fits in the vehicle maintenance environment. For example, data collection should be a by-product of daily operations. Data should be collected at the lowest possible level of the organization and then collated, manipulated, and summarized for reporting information to appropriate higher levels in the organizational structure.

Modern electronic data collection techniques and telecommunications make a startlingly different approach to management information services possible for vehicle managers. The basis of this approach is to use the computer as a device for controlling the flow of work and events inside the maintenance operation rather than using it merely for historically reporting (which is really an accounting function and not a maintenance management function).

The information flow in a modern maintenance management information system could be something like the following:

* When the vehicle is purchased, its serial number (and the serial numbers of major components) are entered into the system.

* When work is to be done on that vehicle, the job is started by a work initiator: 1) preventive maintenance is triggered by a computer generated report based on time or mileage; 2) response to a breakdown is triggered by a telephone call or printed message from the operator or dispatcher; 3) operator defect reporting is accomplished by using a computerized optical scanner triggered by the operator's time card; 4) adverse information from a fluids management system (oil, fuel, transmission fluid, coolant monitoring) is fed from a remote "electronic clipboard" at the fuel pump; 5) corrective work uncovered by preventive maintenance is triggered from a terminal in the garage.

* The computer sorts all these work initiators instantly and presents the foreman with an up-to-date list of all work pending (including previously deferred work).

* The foreman can electronically assign work or defer it based on: 1) vehicle number--if a certain type of vehicle is needed in service; 2) component type--if only certain repair facilities are available; 3) estimated time to repair--if vehicles are in short supply and needed immediately.

* As the worker begins the job, he clocks in with a badge reader and a computer assigned job number.

* As parts and tools are required, the mechanic may find those pre-positioned by the computer (based on the type of work initiator) or charged to the vehicle while he is at the parts window. Of course, this action can also trigger reorder activity in the computerized inventory system. The parts window will already be alerted to save turned-in, warranty related parts for the warranty claim.

* On completion of the work (or his part of it) the mechanic clocks off and prepares for the next assignment.

* The foreman's work queue is automatically adjusted upon completion of the work and all pertinent data relative to that work are stored in the computer.

* From the computer record the following information can be developed for supervisors--for any given reported defect what the most likely cause is, who on the average can repair it the fastest, and how much work has to be accomplished on a shift and skills needed to perform the necessary repair work; for managers--which vehicles require the most repair, automatic processing of warranty claims from parts verification to accounts receivable, which mechanics perform above or below average, which vehicle operators have the most breakdowns, and which garages have the fewest breakdowns, the most repeat work, and the lowest ratios of overtime and absenteeism; for strategic policy makers--whether maintenance performance trends are positive or negative, which vehicle fleets perform better than others, which components have the least life cycle cost, whether it is cheaper to contract outwork or continue to use in-house forces, and what estimates about future budgets can be made with the increased ability to access all the information that the maintenance management information system is capable of providing.

PREVENTIVE MAINTENANCE

The development of the maintenance program depends on the type of vehicle, its intended use, and the operating environment. It is important to recognize from the outset the need for a blend of preventive and corrective maintenance; that blend (expressed as a ratio) may change over time. The ratio of preventive to corrective maintenance depends on the age of the vehicle and the user's ability to tolerate unscheduled breakdowns.

In any vehicle fleet the ability to predict critical component failure means having highly skilled diagnosticians conduct the regularly scheduled preventive maintenance checks.

Whether or not highly qualified talent is available, vehicle fleet managers can employ techniques to achieve much the same end. The preventive maintenance inspector or diagnostician should not, even if a good mechanic, execute the repair work uncovered in the inspection. Human nature suggests that a person will be more likely to call for a difficult, albeit necessary, repair if he knows he will not have to do the job.

Continuous and vigorous retraining of the diagnosticians/inspectors is critical. Diagnosticians should be trained to look carefully for symptoms of a problem and then to look beyond the symptom, in a logical way, for the exact cause of the problem. With continuous retraining and experience, these same individuals, in large vehicle fleets, become the backbone of a post-repair quality assurance team. These people are also candidates for short factory visits during manufacturing inspection and testing.

The preventive maintenance program for a vehicle fleet begins by adhering to the manufacturer s recommended preventive maintenance program, as long as that program is needed to meet warranty requirements. After that time, the program may be adjusted to reflect available human and physical resources, i.e., maintenance personnel and the right tools, equipment, and space. The key to executing a preventive maintenance program is being able to identify and predict critical component failure. Successful motor vehicle maintenance managers know that timely, continuous tracking of the consumption of fluids, i.e., coolant, fuel, lubricants, hydraulic oil, transmission oil, etc., is critical to the identification of premature engine or transmission failure.

Cover photograph courtesy of New Holland Construction, Carol Stream, Illinois.

RELATED ARTICLE: GLOSSARY OF COMPACT EXCAVATOR TERMS

In a tight budgetary environment, the versatility of equipment is critical. Many public works departments are finding compact excavators useful for multiple tasks. The following glossary, supplied by Bobcat Company, clarifies some of the terminology related to compact excavator specification and use.

Arm -- Also referred to as "dipper," it is the structure that connects the excavator's attachment to the boom.

Arm Force -- The Excavator's ability to produce a pulling force, using the arm hydraulic force. This is also referred to as "dipper force,' or crowd force."

Auxiliary Hydraulics -- A dedicated source of hydraulic oil, intended to provide oil flow for specific attachments. The oil is sourced from the excavator's pump system and routed to the attachment via tube lines and hoses on the workgroup. Auxiliary hydraulic flow rates and pressures are a key determinant of an excavator's attachment capacity and compatibility. Flow direction, rate, and duration are controlled by the operator.

Boom -- The primary component of the workgroup that is attached to the house structure via the swing frame. It supports the arm and attachment.

Bucket Breakout Force -- The excavator's ability to produce a "prying force" using the bucket hydraulic circuit.

Compact Excavator -- Also called "mini" excavators. Compact excavators generally include those with operating weights of 14,000 lb or less and dig depths of 14 ft or less.

Control Lockouts -- A safety system that requires the operator to consciously place a console in an "operational" position for predeter. mined hydraulic functions to be active on the excavator. The purpose of the control lockouts is to prevent unintentional movement of the excavator's components.

Control Patterns (ISO or Standard) -- The operating pattern of an excavator's joysticks. There are two predominant joystick patterns on compact excavators. When operating in the ISO pattern, the right-hand joystick controls the boom up/down function, and the left-hand joystick controls the arm in/out function. With the "standard" pattern, these two functions are reversed.

Counter Weight--A weight added to the read of the excavator's house structure in an effort to improve its lifting characteristics. Counterweights are also added to the machine to accommodate variations in arm configurations such as long-arm options or extendable arm options.

Cycle Time -- Cycle time refers to the amount of time, usually in seconds, that a particular function can be cycled (i.e., "boom up"). Cycle time is a means of comparison among excavators.

Expandable Undercarriage -- A variation of the traditional excavator undercarriage in that the undercarriage structure can be expanded. providing a wider machine stance. This allows for increased performance of the excavator when working over the side of the machine, yet when retracted, still allows the machine to enter confined areas.

Extendable Arm -- A telescoping arm structure in place of the standard arm. The extendable arm provides increased reach from trench cleaning or truck loading when needed. It is hydraulically activated and can be used simultaneously with other digging functions. When extra reach is not required, the dipper can be retracted to provide maximum arm-digging force.

Flotation -- The machine's ability to traverse soils or surfaces that have little load-bearing capability.

Gear Pump System -- An oil supply mechanism that produces oil flow from rotating gear assemblies within a pump housing. A gear pump system has a fixed displacement and requires a change in pump shaft speed to affect pump volume.

Independent Boom Swing -- The primary purpose of boom swing is for offset digging around obstacles or along foundations, walls, and forms. A secondary use is cycling in areas too narrow for cab rotation. Independent boom swing is a major advantage of a compact excavator.

Offset Digging -- The practice of excavating with the boom offset to either the right or the left. Offset digging is accomplished by using the boom swing" capability of the compact excavator. Offset digging allows for simple excavation of spoil adjacent to an existing structure. It allows the tracks of the excavator to remain parallel to the trench for efficient repositioning.

Piston Pump System -- An oil supply mechanism that produces oil flow from a rotating assembly of small pistons within a pump housing. Unlike the gear pump system, the piston pump system has the capability to vary oil flow independent of pump shaft speed.

Reach at Ground Level -- Measured from the excavator's center rotational axis to the tip of the standard bucket tooth, at ground level.

Repositioning -- The process of moving the excavator to the next position when excavating. As an operator is trenching and has excavated up to the point where the machine is restricting his digging, the machine is moved back along the path of the intended trench. Repositioning with a compact excavator simply involves raising the blade, activating the travel controls in the appropriate direction, and lowering the blade to the ground.

Slew -- Slewing refers to rotating the excavator's house assembly. The operator can "slew" the entire house and workgroup upon the undercarriage for spoil placement. This introduces minimal fatigue to the operator as his or her body is traveling with the workgroup for maximum visibility and minimal body movement. Compact excavators feature a full 360 degrees of unlimited rotational capability.

Spool Metering -- The ability of the valve assembly to control oil flow to a given function in a consistent and predictable manner.

Tail Swing -- Refers to the rear overhang of the excavator as it rotates upon the undercarriage. It is measured from the central rotational axis to the farthest rear point of the machine.

TOPS/ROPS -- TOPS is an acronym for "Tip Over Protective Structure." ROPS is an acronym for "Roll Over Protective Structure." A TOPS or ROPS rating defines the protection afforded an operator in the event the machine would roll over or tip over. The structural integrity of an operator's compartment must meet standards prescribed by ISO or SAE to be certified as TOPS or ROPS.

Variable Flow Auxiliary Hydraulic System -- Allows for infinite control of oil flow to the excavator's auxiliary hydraulic circuit.

360-Degree Cab Rotation -- The ability to continuously rotate the house 360 degrees, enabling an operator to dig on one side, then rotate and unload the dirt into a truck or onto a pile several yards from the hole. This allows enhanced spoil placement, superior visibility, and minimal operator fatigue.

POOR PCS UNDERMINE MAINTENANCE TECHNOLOGY

Old, outdated, and poorly configured computers are a leading cause of maintenance technology implementation problems. Many problems that occur early in the initial fleet maintenance software setup cause higher than necessary program failure rate.

Arsenault Associates, Inc. (Atco, New Jersey)a maker offleet maintenance software, said a study of agency software support records shows that initial installation problems can often be traced to a computer previously used by another department or individual in the organization. "Providing the fleet maintenance department with a computer that may have been sitting on a shelf in IT department for who knows how long, is a formula for failure. Most often these make-do computers still hold data, software, and all of the operating problems of the previous users," said Charles Arsenault, president.

Arsenault said that PC troubles are frequently traceable to attempts to update older computers by simply removing old programs and cleaning off hard drives, but not verifying that the machine has the memory and processor speed required by the software.

"Arsenault recommends that new fleet maintenance software installations start with at least a "clean machine" if not a new one. "The best thing is a new computer, but if that isn't possible, make sure the computer you do have is properly configured and that it has enough RAM memory and processor speed to handle today's modern software and Internet technologies like online ASP services."

"Erasing the entire hard drive and installing an operating system, then installing your fleet applications may take a few hours, but then you are assured of properly configured software.
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Publication:Public Works
Geographic Code:1USA
Date:Mar 1, 2002
Words:2347
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