INTRODUCTION

Excavator is most of the time a self-propelled Heavy Equipment having for function to dig to ground. Mainly, we find excavators in the following industries like construction, excavation, earthwork, mining, quarry and roads. We also find excavators in the following industries such as forestry, recycling, demolition, lakes and rivers cleaning.It is a common fact that we find a wide variety of construction machines on every construction sites, which make the construction jobs easy, safe and quicker. Good project management in construction must vigorously pursue the efficient utilization of labour, material and equipment. The use of new equipment and innovative methods has made possible wholesale changes in construction technologies in recent decades. The selection of the appropriate type and size of construction equipment often affects the required amount of time and effort and thus the job-site productivity of a project. These act as a backbone in the case of huge construction projects. Proper use of the appropriate equipment contributes to economy, quality, safety, speed and timely completion of a project. Equipments are used for highway projects, irrigation, buildings, power projects etc. Almost 15-30% of total project cost has been accounted towards equipment and machinery. It is therefore important for site managers and construction planners to be familiar with the characteristics of the major types of equipment most commonly used in construction.

DEFINITION

Hydraulic power is the key to the utility of many excavators. Hydraulic front shovels are used predominantly for hard digging above track level and for loading haul units. Hydraulic hoe excavators are used primarily to excavate below the natural surface of the ground. There are many variations in hydraulic excavators. With the options in types, attachments, and sizes of machines, there are differences in appropriate applications and therefore variations in economic advantages.Hydraulic power is the key to the advantages offered by these machines. The hydraulic control of machine components provides faster cycle times, outstanding control of attachments, high overall efficiency, smoothness and ease of operation and positive control that offers greater accuracy and precision.Hydraulic excavators are classified by the digging motion of the hydraulically controlled boom and stick to which the bucket is attached. A downward arc unit is classified as a "hoe." It develops excavation breakout force by pulling the bucket toward the machine and curling the bucket inward. An upward motion unit is known as a "front shovel." A shovel develops a force by crowding material away from the machine Hydraulic excavators are classified by the digging motion of the hydraulically controlled boom and stick to which the bucket is attached.A downward arc unit is classified as a "hoe." It develops excavation breakout force by pulling the bucket toward the machine and curling the bucket inward. An upward motion unit is known as a "front shovel." A shovel develops a force by crowding material away from the machine. The boom of a shovel swings upward to load therefore; the machine requires a material face above the running gear to work against.

DEFINITIONExcavator is very versatile heavy equipment. With the times, excavators reveal it more than simple digging machine. His constitution allows him to access many configurations and with the appropriate attachment, excavator can transform itself into heavy equipment. Thus, with a delimber boom or feller processor head, excavator turns itself into forest machinery. With Grapple installed on his arm end, excavator can be used like a log loader or a refuse sorting machine. With a shear, excavator takes the role of demolition equipment without parallel capacity to cut concrete and metal structures. With hammer, excavator can break stones, with drill he dig deep hole. Besides that, with extended boom excavator can contribute to lakes and rivers cleaning.