• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1473-1478
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• 2000

Severe fork-lift truck noise is annoying to an operator as well as one of the noise pollution elements. This paper presents the noise contribution analysis of a cabin type fork-lift truck to identify the major sources and its usage to reduce the interior noise level. The methodologies for this work are sound field analysis, sound intensity test, insertion loss test of duct system and etc. An effective method to suppress interior noise level of fork-lift truck and design guides are suggested.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.04a
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• pp.155-160
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• 1996

The vibration analysis of the automobiles has been a good subject for the engineers seeking solutions for more comfortable life. In the area of industrial vehicles, however, the seriousness of the vibration annoyance has not been considered so much. In this paper, a finite element model was built which was good for the low-frequency system(of fork-lift truck), and a forced vibration analysis was obtained for the component of 2n of harmonic orders from engine excitation to this model. Finally, a design optimization upon dynamic responses was made to minimize the vibration acceleration level at selected points representing the vibration level of the whole system.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.913-914
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• 2006

In industrial field, electric fork-lift has been mainly powered by batteries which are varied from DC 36V to 80V. Operating electric fork-lift truck depends on stable electric power supplies which are ensured by using Switched Mode Power Supply (SMPS). This paper presents design of SMPS for stable electric power supply. The SMPS has much strength such as high effectiveness, low cost and high stability of output voltage. At the same time, SMPS is small and multi output and has simple design of circuit.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1176-1178
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• 1992

This paper shows enhanced working performance of the battery fork-lift truck by developing the IGBT full bridge dc-dc convertor using one-chip micro-processor. The PWM pulse is generated from a 16 bit one-chip micro-processor for the speed control of DC motor. In order to ensure the operation of IGBT and motor pecewisely, IGBT gate drive circuit was designed by using current limiting IC and hige voltage limit IC. And also It is able to regenerative braking.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.2
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• pp.124-129
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• 2018

A forklift is used to lift materials above a height of 2 m. The width of the fork determines the weight of the material it can carry. In this paper, three models of fractured forklifts were analyzed to determine if the fracture was caused by load fatigue due to the width of the fork. The position of the fork was fixed on each model, and a 2.5 ton load was placed at the upper part of the fork. The width distances on each of three models were 500 mm, 750 mm and 1000 mm, and the maximum equivalent stresses were 237.5MPa, 227.62MPa and 230.99MPa, respectively. This analysis demonstrated that as the load increased with use of the wider fork, the fatigue life remained to be nearly equivalent irrespective of fork width among all three models. The results of this study contribute to the durability and safety design of forklifts.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.557-563
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• 1997

In order to satisfy the regulations concerned with the noise emission of fork-lift trucks and thereby increase export to the western countries, a noise reduction technique should be developed in the early design stage. In this paper, several noise sources are identified using the sound suppression method and sound intensity measurement, and their contributions to the sound levels at the operator's ears and at the distance of 7m from the vehicle are studied. For each of the major noise producting components, noise abatement alternative are suggested and their effects are analyzed.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.11
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• pp.1309-1315
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• 2011

The design process for obtaining the reliable steeraxle casting beam of fork lift truck is studied in this paper, as the casting beam is major component of steeraxle which has a steering function at driving. In this study, the driving mode and damage pattern of casting beam which could be occurred from the customer site were analyzed and it established the design process to predict the fatigue life by FEA(Finite Element Analysis) so that the reliability of steeraxle casting beam could be verified at DVT(Design Validation Test) mode. This paper provides guidance on the process of designing the reliable steeraxle casting beam at the initial design stage and also, provides guidance on the process of solving the problem when the failure is occurred in the field.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.99-103
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• 1995

소음저감 설계기술은 제품의 경쟁력 향상을 위해 자동차, 항공기, 건설 장비, 선박, 심지어 가전 제품에 있어서도 소음 문제에 대한 관심이 크게 대두되고 있다. 특히 수출을 하기 위해서는 그 지역의 소음 규제법을 만족시켜야 하며 제품의 경쟁력을 위해서는 그 이상의 것이 요구되고 있다. 또한, 소음 문제는 소비자의 제품구매 선택에 영향을 주기도 한다. 일본의 경우 JIS 규격으로 건설 장비의 소음을 규제하고 있으며, 소음수준에 따라 일반 장비, 저 소음 장비, 초 저소음 장비로 구분하여 장비에 따라 건설 작업을 제한하기도 하며, 특히 초 저소음 장비 인증을 받은 것은 장비 사용 단가 및 사용에 있어 차등을 두어 혜택을 주고 있다. 본 논문에서는 현재 구미지역에서 소음규제로 사용되는 BITA 방식에 따라 지게차의 소음원 규명 및 소음 저감 대책을 논하고자 한다.