• Journal of the Ergonomics Society of Korea
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• v.31 no.3
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• pp.469-474
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• 2012

The aim of this study is to develop an ergonomic design of magic saw handle considering user experiences. Background: Frequent use of hand tool can cause musculoskeletal disorders by inadequate wrist posture, excessive strength, repetitiveness, friction and pressure, vibration, etc. A hand tool that is inappropriately designed has higher risk causing musculoskeletal disorders. Complaints for the design of magic saw handle has been raised by many users according to the increasing use of magic saw. Method: Hand tool has to be designed considering worker's characteristics and task condition to prevent worker's musculoskeletal disorders. For this, user experiences for magic saw handle were measured through questionnaire survey and observation. Results: An ergonomic design of magic saw handle considering user experiences was proposed and then its design suitability was evaluated in comparison with the existing handle design using EMG and subjective evaluation. Conclusion: The proposed handle design showed higher satisfaction and lower muscular fatigue. Application: The results of this study can be effectively used to develop a new magic saw.

• Journal of the Korea Safety Management & Science
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• v.16 no.4
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• pp.371-378
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• 2014

Manual materials handling tasks are the main risk factors for the work-related musculoskeletal disorders. Many assistant tools for manual materials handling are being used in various kind of industries. One of them is a 4-wheeled cart which is widely used in manufacturing factories, hospitals, etc. The major force required to control the 4-wheeled cart is pushing and pulling. There are two types of handles being used for the 4-wheeled cart : vertical type (two vertical handles), and horizontal type (one horizontal handle). This study tried to investigate the pushing forces and subjective discomforts (hand/writst, shoulder, low back, and overall) of the two handle types with different handle height and distance conditions. Twelve healthy male students (mean age = 23.4 years) participated in the experiment. The independent variables were handle angle (horizontal, vertical), handle height (low, medium, high), and handle distance (narrow, medium, wide). The full factorial design was used for the experiment and the maximum pushing forces were measured in 18 different conditions ($2{\times}3{\times}3$). Analysis of variance (ANOVA) procedure was conducted to test the effects of the independent variables on the pushing force and discomfort levels. Handle height and angle were found to be the critical design factors that affect the maximal pushing forces and subjective discomfort. In the middle height, subjects exerted higher pushing forces, and experience lower discomfort levels compared to the high, and low height. There was no statistical influence of the handle distance to the pushing forces and subjective discomfort levels. It was found out that the effects of the handle angle (horizontal and vertical) on both pushing force and subjective discomfort were statistically significant (p < 0.05). The vertical handle revealed higher pushing force and lower discomfort level than the horizontal handle. The reason for that was thought to be the different postures of the hand when grasping the handles. The horizontal handle induced pronaton of the hand and made hand posture more deviated from the neutral position.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.123-129
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• 2013

Among various manual materials handling tasks, pushing/pulling was known to be one of the risk factors for the low back and shoulder musculoskeletal disorders (MSDs). This study was conducted to find out an optimal solution set of the handle height and distance for 4-wheel cart with two vertical handles. Ten male college students participated in the pushing force measurement experiment. The face-centered cube design, one of the central composite designs, was applied for the experiment, and the isometric voluntary pushing force was measured in 9 treatment conditions. The second order response surface model was predicted by using the pushing strength as a response variable, and the handle height and distance as independent factors. According to the 2nd order response model, the handle height and distance showed nonlinear relationship with the isometric pushing strength. To maximize the 2nd order response model (pushing force), the handle height and distance were optimized. The optimal handle height was 'xyphoid process height - stature', and the optimal handle distance was '$1.25{\times}shoulder$ width'. When calculated using the anthropometric data of the subjects of this study, the optimal handle height was $115.4{\pm}3.4$ cm, slightly higher than the elbow height, and the handle distance was $52.9{\pm}2.3$ cm.

• Journal of the Korea Furniture Society
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• v.21 no.3
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• pp.253-260
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• 2010

The drop handle in the Chosun-Dynasty played a role lifting up the cabinet and box which was attached to and besides this had the decoration function. The scope of this study should include the drop handles from the $18^{th}$ century up to now by investigating and analyzing their definition & function and furthermore the types of their designs. The object of the study was the drop handle having 2 golden fixing parts which are definitive difference from ring or loop, and the design typology of drop handle was concentrated on the handle part, and it can be classified in two types. The one is the figuration of bow, bat, bamboo, fish and bird and so on from the motive of nature on the handle part, and the other one is the drop handle of the simple ㄷ-shape, the temple-symbol shape or geometrical forms. According to the analysis of relics & literature from the past it was found that there were more quantitative nature-motive figurations than the geometrical forms. The nature-motive figurations were again classified in box-, bat-, cloud- bamboo-, fish- and bird-type, and the geometrical forms in ㄷ-shape, the temple-symbol shape and others. The cases applied to furniture are roughly divided into the front-attached type and the side-attached type. In comparison of the drop handle in the Chosun-Dynasty with that of modern times, ㄷ-shape and bow-type keep the long tradition of the drop handles despite of the constructive change partly. Ring-type is similar to the just ring or loop of the part and drop handle with one golden fixing part, while the knob-type shows almost same forms in the past as well as in the modern times. Which type among handles in the modern times has little connection with the past is the reclaimed type, and it was showed in the Chosun-Dynasty and also is showed up to now identically that the man-made hole on the front side of the drawer for the function as handle.

• Proceedings of the Korea Society of Design Studies Conference
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• 2001.05a
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• pp.128-129
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• 2001

• Journal of the Korea Furniture Society
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• v.27 no.2
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• pp.104-110
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• 2016

The aim of this study is to develop and suggest the handle for lockers according to the design process which are used for keeping of student's personal stuffs such as books, writing implements and gym uniform in elementary, middle and high school and university as well. This includes the design development for ILGUMTUR which is specialized for office furniture, but does not own the intellectual property right yet. The design concept based on the domestic locker market survey is recessed handle at low- to intermediate price and it's material should be plastic what is solid and light. The lock system should be constructed by molding process and the name plate can be exchanged every time the owner of locker changes. Contrary to the right angle of it's external appearance, the handle of the locker is designed to be softly round and the simplicity is pursued for an easy production. On the basis of this design concept the sketch has been drawn and upgraded in full by 3D-rendering. Then the mock-up has been completed by 3D printer and ILGUMTUR has obtained a patent for the locking system based on the rotation of 2 circles.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.357-360
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• 2011

In these days, the passenger vehicles usually have equipped various comfort & security systems to appeal to customers. And then, the importance of emotional quality gives added weight to the noise performance of those system devices. Door inside handle system is one of the most popular devices for passenger. This paper shows developing process about the operating sound of door inside handle. We used DFSS process to develop the door inside handle snap back sound and confirmed the improvement.

• Journal of the Korean Society of Safety
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• v.27 no.2
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• pp.84-91
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• 2012

This study evaluated three forces (lifting, pushing and twisting) required to maneuver the single-wheel barrows according to handle height, width, horizontal angle and vertical angle. The four independent variables were varied in two levels. Handle height was varies in two levels : 'knuckle height (KH)' and 'KH + 0.1 ${\times}$ stature'. The two handle widths were '1.5 ${\times}$ shoulder width (SW)' and '1.75 ${\times}$ SW'. Two angles of $0^{\circ}$ and $15^{\circ}$ were used for horizontal and vertical angles. The 24 factorial design was used in the experiment. Twelve healthy male students (undergraduate and graduate) participated in the experiment. Subjects exerted three forces (pushing, lifting, and twisting clockwise) in each experimental condition. The order of 16 treatment conditions was determined randomly. Results showed that the effects of the four factors were different according to three forces. While lifting and twisting forces were higher in 'knuckle height', the pushing force was higher in 'KH + 0.1 ${\times}$ stature' (p < 0.05). Lifting and pushing forces showed higher values in the horizontal angle $0^{\circ}$ than in $15^{\circ}$. Handle width and vertical angle showed no statistically significant main effects on three forces (p > 0.05). Results of this study could be used as basic data for the ergonomic design of handle variables of one- or two-wheel barrows.

• Archives of design research
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• v.19 no.1 s.63
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• pp.293-302
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• 2006

clay cups with handles made in studios in Korea and the United States were selected and analyzed. The shape of cup were fixed to ensure proper comparison between handle size of the cup and position. The variable factors were the thickness of the handle, the number of fingers required to hold the cup, the relationship between the handle's shape and the position of its attachment to the cup, the effect of the handle's setter, the change in shape of the handle's thickness, and the relationship between the cup's weight center and handle. Preference test were designed and tested to the users, and the results were analyzed. The results showed that to make a comfortable handle, it is important to incorporate the shape of the resting hand in the design of the handle. Specifically, the design should be such that the cup can be held comfortably. This is possible if the weight of the cup is spread evenly when several fingers are inside the handle's curve and if such factors as the hand size, the curve of the fingers, and the position that best controls the cup's weight center are carefully considered. At this time, if there is a setter for the thumb, a cup of the same weight can be lifted more lightly. In the design of such a cup, the oval line is drawn by extending the cup's handle toward the direction of the cup's body. If the cup's weight center is located on the oval line, the cup's handle may be said to be effective. In such a case, the nearer the handle is to the cup's body weight center, the less power is needed to lift the cup efficiently. Our test results can be applied as a powerful tools in design and manufacturing cups with handle in terms of artistry and functionality.

• Journal of Aerospace System Engineering
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• v.12 no.2
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• pp.59-65
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• 2018

The landing gear (L/G) handle of an aircraft is an essential piece of equipment for aircraft take-off and landing. The bracket in the landing gear handle was fractured during a vibration test when developing the landing gear handle. This paper summarizes the vibration test procedures performed during landing gear handle development. A cause analysis, design improvements, and verification results of the fault in the vibration test are also provided.