• 한국생산제조학회지
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• 제25권2호
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• pp.149-155
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• 2016

The purpose of this study is to develop special tools used to extend the tool life for the boom of heavy equipment. The boom of heavy equipment is manufactured by cutting the inner and outer surface with respect to the assembly site essential. In particular, when cutting the inner surface, entry of the tool is difficult owing to the limited size of the inner diameter and non circular cutting. In addition, the productivity is poor because the use of the cutting tool made of the SKH material. Therefore, it is necessary to develop a special tool for machining heavy equipment boom to extend tool life and to improve productivity. The special tool developed this study has the form of a holder and tip. The tip was created by applying a commercially available tungsten carbide insert.

• 산업경영시스템학회지
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• 제46권spc호
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• pp.61-67
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• 2023

Special equipment used for snow removal is only used in the winter and must be moved into storage during non-winter seasons. However, when moving heavy equipment using a forklift within a limited space, safety accidents may occur due to deformation and damage due to the worker's limited visibility and excessive loading of heavy objects. In this study, the scissors boom of the developed heavy load transporter was conducted in two cases: link structural analysis and position-based structural analysis. In detail, the link structural analysis covers four cases of stress and safety factor according to material and thickness to optimize the specifications of the material selected during development, and the structural analysis according to position covers two cases before and after the lift, when maximum stress concentration is achieved. Safety was evaluated through finite element analysis. As a result of the study, when manufacturing a scissors boom type heavy load transporter that can withstand a load of 10 tons, the link showed safety at SS400 4.5mm or higher, and reinforcement is needed in the upper and lower structures, so it is judged to be useful in applying materials according to the load.

• 드라이브 ㆍ 컨트롤
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• 제14권2호
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• pp.23-29
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• 2017

In this study, a flexible multi-body dynamic simulation model of a knuckle boom crane is developed to evaluate the stress of spindle and rack gears under dynamic working conditions. It is difficult to predict potential critical damage to a knuckle boom crane if only the static condition is considered during the development process. To solve this issue, a severe working scenario (high speed with heavy load) was simulated as a boundary condition for testing the integrity of the dynamic simulation model. The crane gear model is defined as a flexible body so contact analysis was performed. The functional motion of a knuckle boom crane is generated by applying forces at each end of the rack gear, which was converted from hydraulic pressure measured for the experiment. The bending and contact stress of gears are theoretically calculated to validate the simulation model. In the simulation, the maximum stress of spindle and rack gears are observed when the crane abruptly stops. Peak impact force is produced at the contact interface between pinion and rack gears due to the inertia force of the boom. However, the maximum stress (bending/contact) of spindle and rack are under the yield stress, which is safe from damage. By using the developed simulation model, the experiment process is expected to be minimized.

• 플랜트 저널
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• 제8권2호
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• pp.59-69
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• 2012

This study focuses on avoiding the failures from the wrong selections by experiences as simulation programs is not available, and suggests the methods which effectively select the alternatives when the selected model is not appropriate for the original plan. First, CC8800-1K of DEMAG has the longest boom whose length is 216 m at the maximum. The combination of the boom is feasible to second level except for MANITIWOC M 2250 (M-1200 RINGER) which is possible to third level. Second, the angle of boom is from 20 degrees to 82 degrees. Suitable angle to work is in the 55-78 degrees. The working load of crawler type and hydraulic one to be applied is 75-85% in the critical loads capacity. As increasing operating radius, crawler type is a favorable position over hydraulic one. Lastly, related problems were verified through examination by suggestions for the design of the selection methods for the case analysis. The major problems are stemming from the selection based on its experiences, unreasonable demand for the existing facility and repeated selections by the designer who accumulates his experiences via same or similar projects.

• 문화기술의 융합
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• 제5권3호
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• pp.263-269
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• 2019

본 연구에서는 붐 길이를 측정할 수 있는 센서, 붐 및 로더의 좌우측의 경사를 측정할 수 있는 각도센서 그리고 리프팅 시 무게를 측정할 수 있는 로드셀 등의 여러 센서를 장착한 다목적 로더의 특성과 운행에 관련된 데이터 값을 디스플레이하는 시스템을 구현하였다. 시스템의 구성은 다음 각종 센서로부터 값을 읽어와 이를 차량제어기에 보내고 제어기에서 계산한 전복률 결과와 기타 중요한 정보를 디스플레이 장치에 CANOpen 프로토콜을 이용하여 전달하게 하였다. 또한 전복률 계산에 있어서는 다목적 로더의 구조가 중장비에 속하는 크레인의 구조와 비슷하여 크레인 전복률 계산방식을 사용하였으며 좌우 경사도에 따른 전복 위험성은 실험을 통하여 전복가능성이 있는 좌우 경사각을 추출하였다. 본 연구를 통하여 중장비 차량의 상태를 관찰하며 전복 등의 비상 상황을 디스플레이 장치를 통해 사전 인지할 수 있게 하였다.

• 대한기계학회논문집A
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• 제34권12호
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• pp.1901-1907
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• 2010

굴삭기 유압실린더는 붐, 암, 버킷과 같은 작업장치를 작동시키는 핵심 부품이다. 일반적으로 유압실린더는 반복적인 고압으로 인해 좌굴이나 피로 파손과 같은 구조적 문제가 종종 발생한다. 따라서, 유압실린더의 내구설계 시 설계수명 동안의 피로, 항복, 좌굴 등에 대한 구조 안전도 평가가 반드시 이루어져야 한다. 내구설계는 기본설계와 상세설계 두 단계로 구성되는데, 기본설계 단계에서는 굴삭기의 작업능력, 작업속도, 작업영역 등을 고려하여 항복과 좌굴 안전도를 만족하도록 로드와 튜브의 주요 치수를 결정한다. 상세설계 단계에서는 로드 노치, 용접부, 튜브 끝단, 글랜드, 오리피스, 쿠션링 등의 상세치수를 주로 피로 안전도 측면에서 결정한다. 본 연구에서는 이러한 내구설계의 전반적인 절차와 각 설계 단계에서 내구설계 평가를 위한 해석기법에 대해 기술하였다.