• Journal of the Korea Safety Management & Science
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• v.24 no.3
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• pp.23-28
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• 2022

Rack is a place to store products. Workers pick products from rack storage. After picking up, workers move to another location by forklift. Driving speed, worker condition, and number/frequency of operation is responsible for forklift accidents. When an accident occurs, products get damaged. Therefore, it is important to prevent one. As the research result, To prevent forklift accidents, the minimum order quantity, the minimum number of operations, and low speed operation are required.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.4
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• pp.313-323
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• 2017

Objectives: This study aimed to assess exposure to black carbon(BC) among forklift operators and to identify environmental and occupational factors influencing their BC exposure. Methods: We studied a total of 23 forklift operators from six workplaces manufacturing paper boxes. A daily BC exposure assessment was conducted during working hours from January to April 2017. A micro-aethalometer was used to monitor daily BC exposure, and information on work activities was also obtained through a time-activity diary(TAD) and interviews. BC exposure records were classified into four categories influencing BC exposure level: working environment, workplace, forklift operation, and job characteristics. Analysis of variance(ANOVA) was used to compare average BC exposure levels among the four categories and the relationships between potential factors and BC exposure were analyzed using a multiple linear regression model. Results: The operators' daily exposure was $12.9{\mu}g/m^3$(N=9,148, $GM=7.5{\mu}g/m^3$) with a range: $0.001-811.4{\mu}g/m^3$. The operators were exposed to significantly higher levels when they operate a forklift in a room ${\leq}20,000m^3$($AM=12.3{\mu}g/m^3$), in indoor workplaces($AM=16.3{\mu}g/m^3$), when they operate a forklift manufactured before 2006 ($AM=13.2{\mu}g/m^3$), a forklift with a loading limit of four-tons($AM=27.1{\mu}g/m^3$), with a roll and bale type clamp($AM=17.1{\mu}g/m^3$), and with no particulate filter($AM=15.7{\mu}g/m^3$). Conclusions: Occupational factors including temperature, smoking, season, daytime, room volume($m^3$), location of operating, and manufacturing era and model of forklift influenced the BC exposure of forklift operators. The results of this study can be used to minimize the BC exposure of forklift operators.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.577-581
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• 2006

In this study, it is presented a vibration cause of an electronic forklift by a variable excitation through experimental methods. It is presented a vibration influence by a variable excitation and established an FE model about structure vibration. It is used an FE model and presented parameters causing the vibration. It is presented a mechanism causing the vibration of the electronic forklift and proposed a vibration reduction of the electronic forklift.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.912-918
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• 2004

Main vibration problems of a transaxle type forklift truck are caused by the resonance of engine excitation force and natural mode shade of major components such as engine-mount system, mast, and main frame. But, it is well known that the reduction of vibration is very difficult because of the limitation of structural modifications. In this paper, the vibration characteristics of engine-mast system including engine mount were firstly identified by the experimental and simplified numerical methods. And also, the free and forced vibration characteristics of a whole forklift truck were surveyed with modal test and ODS(operation deflection shape) measurement. Based on these results, the reliable finite element model was developed. Finally, various countermeasures were considered and applied to a real forklift truck and then its effects were confirmed.

• Journal of the Korea Safety Management & Science
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• v.22 no.3
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• pp.9-14
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• 2020

A forklift accident occurs in the logisitcs center. there are many kinds of accidents such as a casualty accident or a minor accident, etc. there are many other causes of accident, including poor visibility and habitual operational mistakes The result of the accident is the phenomenon of cutting, falling, scratching of the product. In the case of minor accidents, workers do not report accidents, so the occurrence of accidents is unknown. The customer receives the goods and then notifies them that they are defective product. After the product is returned, we can see that the forklift accident caused the problem of the product The result of the late response affects the image of the enterprise. In this study, we recognized the need for safety education to prevent accidents and found out which of the education items could raise awareness of safety. As result of the study, disinfection and forklift maneuverability regarding speed were mentioned as the most important items in education.

• Journal of Drive and Control
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• v.19 no.4
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• pp.70-76
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• 2022

In this paper, we develops an unmanned test system for the purpose of realizing an actual forklift-based test-bed for the operation durability of the forklift mast. First, two robot actuators were applied to the lever to replace lever manipulation of the operator. For detecting the height of the fork and the tilt angle of the mast, the laser displacement sensor and the inclinometer were installed to the forklift. Next, the embedded control system was used to control the robot actuator with reference to test mode. Experimental evaluation verified that developed test system was effective and practical for the viewpoint of the repeatability of the test mode.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.1
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• pp.38-47
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• 2016

Objectives: The objective of this study was to determine the exposure levels of forklift operators to diesel engine exhaust(DEE) using black carbon(BC), elemental carbon(EC), and nitrogen dioxide($NO_2$) as indicators. Methods: A total of eight forklift operators in six collection companies were assessed over a period of two months from July to September 2015. BC was measured using a real-time monitor and respirable EC samples were analyzed using the NIOSH method 5040. $NO_2$ samples were collected using a passive badge-type sampler. Results: The geometric mean of BC, EC and $NO_2$ were $3.1-19.1{\mu}g/m^3$, $2.1-23.8{\mu}g/m^3$, and 12.5-166.6 ppb at all companies. When forklifts were operating both outside and inside, BC concentrations increased 2.0-5.6 times. The highest increase was observed when forklifts were operating indoors. The increase in BC concentrations varied by company(company A: 2.0 times, B: 3.2 times, C: 5.6 times, D: 2.1 times, E: 5.1 times, F: 2.6 times). The geometric mean of BC, EC, and $NO_2$ for the forklift operators was $9.6{\mu}g/m^3$, $7.9{\mu}g/m^3$, and 48.9 ppb, respectively. The geometric mean of BC, EC, and $NO_2$ for manufacturing workers was $9.3{\mu}g/m^3$, $0.9{\mu}g/m^3$, and 85.2 ppb, respectively. The mean BC and EC exposure levels for the forklift operators were slightly higher than those for manufacturing workers, but $NO_2$ levels for manufacturing workers were higher than those for the forklift operators(p>0.05). Multiple regression analysis revealed that diesel exhaust emissions standard, forklift weight and forklift manufacturer were the most influential factors in determining worker exposure. Conclusions: In the DEE work environment, workers who perform tasks within the workplace as well as inside forklifts as operators are likely to be exposed to a lack of ventilation. Further study of forklift operators' exposure to DEE indicators should be conducted to include a wider range of occupational and environmental situations, such as collection procedures, seasonal situations, types of fuel used, and number of forklifts.

• Journal of the Korea Society for Simulation
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• v.27 no.2
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• pp.71-81
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• 2018

Forklifts in a shipyard lift and transport heavy objects. Tasks occur dynamically and the rate of the task occurrence changes over time. Especially, the rate of the task occurrence is high immediately after morning and afternoon business hours. The weight of objects varies according to task characteristic, and a forklift also has the workable or allowable weight limit. In this study, we propose an online forklift dispatching algorithm based on nearest-neighbor dispatching rule using minimal cost assignment approach in order to attain the efficient operations. The proposed algorithm considers various types of forklift and multiple jobs at the same time to determine the dispatch plan. We generate dummy forklifts and dummy tasks to handle unbalance in the numbers of forklifts and tasks by taking their capacity limits and weights. In addition, a method of systematic forklift selection is also devised considering the condition of the forklift. The performance indicator is the total travel distance and the average task waiting time. We validate our approach against the priority rule-based method of the previous study by discrete-event simulation.

• Journal of Advanced Navigation Technology
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• v.23 no.2
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• pp.200-206
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• 2019

The most frequent type of safety-accident in industry is the overturning of forklift. The leading cause of this accident is overload in forklift. Thus, it is needed to measure the weight on board of forklift. The most common method is based on load cell, and this method has the merit of high accuracy. However, high price is the disadvantage of this method. In this paper, we propose the new measurement system of the weight on board of forklift based on the strain gauge sensor, which has the disadvantage of low accuracy. The differentiation of the proposed system is that the shape of the strain gauge sensor customized for anchor bolt of forklift in order to improve the accuracy and durability. In system four strain gauge sensors are inserted into four anchor bolts. The test result shows that 1% error of measurement is obtained in the proposed anchor bolt type strain gauge sensors.

• Journal of Drive and Control
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• v.18 no.1
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• pp.1-8
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• 2021

This paper presents research on methods for the reduction of forklifts' noise level for the increased comfort and safety of its operator. A cooling fan with a high air volume flow rate installed in the forklift acts as an important design parameter which efficiently cools the heat exchanger system, helping to transfer internal heat from the engine room to the outdoors with both transmitted and diffracted opening noises. The cooling fan contributes significantly to both the forklift's emitted sound power and the operator room's noise level, thereby necessitating research on the forklift's reduction of acoustic power level and transmission. A noise analysis for various fan models with a biomimetic design based on eagle-wing geometry was conducted. In addition to the acoustic power generation, the aerodynamic performance of the cooling blade is also strongly influenced by the design of airfoil distribution, thereby requiring optimization. The cooling fans were fabricated and installed in the forklift in order to check the efficacy of the forklift engine's cooling, and the final version of the fan was measured for its ability to lower acoustic power level and cool the engine room. This study explains the aerodynamic and acoustic features of the designed fans with the use of BEM analysis and forklift test results.