PURPOSES : In this study, the amount of core stone breaking in the size of boulders by excavator braker work was analyzed quantitatively through on-site test construction. In addition, the factors affecting workload were studied. METHODS : In the field test, 30 core stones of boulder sizes (1–4 m3) that appeared during earthworks, such as road construction and site construction, were collected from three locations, and the rock breaking work was carried out simultaneously using three excavator breakers(1.0-m3 volume). During the core stone breaking, progress was analyzed through video recordings. RESULTS : After the completion of rock breaking, the amount of breaking work was analyzed by direct loading and weighing using a 15- ton dump truck. As a result of the test construction, there was a significant difference in the amount of work completed per hour. CONCLUSIONS : It was found that the results were greatly affected by not only the performance of the excavator braker equipment, but also the skill of the driver and the size of the core stones.

Recently, in construction vehicles like exacavator, many customers demand the interior parts to be convenient and handy to operate. Futermore, that parts had to be more lightweight and better quality and durability. For this reaseon, the combination switch, a part for operation of head lamps, wipers, horn, etc, had been designed as a new lightweight structure by using PA plastics material and had been changed the mechanical contact into electric non-contact by using Hall IC and FET.

Excavator working in the quarry and junkyard, is very difficult to move the things in the truck, because the position of the cab is low, eyesight is not visible. The cab visibility, safety and ease of operation is obtained by the development of the cab lifting system moving the position. To apply cab lifting system on the existing excavator, development of new sub-frame is positively necessary. In this study, the sub-frame, which is suitable for its main function, is manufactured and is verified through hardness test, finite element analysis and endurance test.

This study carried out the investigation about the actual conditions of the management, disaster analysis and safety awareness on excavator in one of construction equipment and tried to make it's preventive measures. To achieve this, first of all, the accident of the internal Construction Industry process Investigation and Analysis, and then analyze an cause of accident based on it. Next, For the conditions of safety management conduct a survey to Investigation and Analysis and Propose preventive measures. The results of this study can be summarized as follows. 1st, Status of safety awareness and management of construction equipment tend to seek quickly and easily for the interests of sight. 2nd, Half the precincts of the equipment is causing major disaster. 3rd, The risk of excavator operation's indicators and drivers is so much potential. 4th, The preventive measures are needed for strengthening safety education, professional legal education, changes in safety awareness, the development of prevention system.