• Current Research on Agriculture and Life Sciences
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• v.27
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• pp.7-11
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• 2009

Persimmon occupied the second largest cultivation area next to apple among the fruits in Korea. Since 70 % of its cultivating field is located at slope, the efficiency of its harvesting operation is very low. Also, the traditional high-ground trimmer show very low efficiency due to its structure problem.. In this paper, a high-ground trimmer which is a persimmon cultivator was developed by solving the problem of a traditional high ground trimmer. The results of the research are summarized as follows : 1. In case of the developed hydraulic type high ground trimmer, the required average lever tension is 2.9 N. 2. However, the required average tension force of the existing spring type is 25.5 N, which was 8.7 times greater than developed hydraulic lever type trimmer in this study.

• Journal of Korean Society of Steel Construction
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• v.28 no.6
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• pp.459-465
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• 2016

In this paper, it was performed the fatigue test to examine the effect of cyclic loading for the simple T-joint. Axial force of bolt by clamping and the change of the force by applied load were measured in the joint. And the bolt force, the failure mode and the fatigue strength under cyclic loading were investigated. The parameters of the tension joint were set to be the flange thickness and the diameter of bolt to a different stiffness of the joint in response to the combination. From the fatigue test, failure mode of tensile joints under cyclic loading could be evaluated using a static ultimate load of the specific failure mode in EC3. The fatigue strength of the tension joints was considerably higher than the fatigue strength of the EC3(36) that does not consider a lever action. However, the additional axial force by lever action occurs to an increase in the axial force of the bolt it requires a careful evaluation of the fatigue strength.

• The Research Journal of the Costume Culture
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• v.21 no.6
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• pp.967-973
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• 2013

During high speed sewing, the needle thread is exposed to dynamic loading, short strike loading, inertia forces, friction, rubbing, force of check spring, bending, pressure, friction, impact, shock and thermal influence. The dynamic thread loading/tension alters throughout the stitch formation cycle and along its passage through the machine. The greatest tensile force occurs at the moment of stitch stretching, when the take up lever pulls for required thread length through the tension regulator. These stresses act on the thread repeatedly and the thread passes 50-80 times through the fabric, the needle eye and the bobbin case mechanism, before getting incorporated into the seam, which result in upto 40% loss in tensile strength of the sewing thread. This damage in the sewing thread adversely affects its processing and functional performance. In this paper, the contribution of dynamic loading, passage through needle and fabric, and bobbin thread interaction in the loss in tensile properties has been studied. It is observed that the loss in tensile properties occurs mainly due to the bobbin thread interaction. Dynamic loading due to the action of take up lever also causes substantial loss in tenacity and breaking elongation of cotton threads.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.751-755
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• 2011

Electric Parking Brake(EPB) is the system operated by electric control actuator. It differs from the mechanical parking brake system which is operated by lever and pedal in need of human power. The EPB system is composed of DC motor, helical and differential epicyclic gear, screw, cables, and sensor. This paper describes about the EPB system mathematically and constructs a modeling of the EPB system using MATLAB/SIMULINK. Especially, SimMechanics library in SIMULINK is used to make each parts of system a module. By made modeling of the friction torque between bolt and nut. Cable tension can be maintained after the motor operating stops.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.3
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• pp.394-410
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• 1993

This study was accomplished for appreciation of the mandibular moments according to antero- posterior movement of pivot placed on the lower natural dentition. For this study, 20 subjects(male, $21\sim30$ yrs., average age 24) in the category of normal occlusion were selected, and the intraoral Vitallium clutches were cast and fabricated for each subjects. A 2-dimension PSD(Position Sensitive Detector, Hamamatsu Photonics Co., Japan) was attached to maxillary clutch in a mode of three dimensional control and LED (Light Emit Diode, Hamamatsu Photonics Co., Japan) was set up on mandibular clutch. Both clutches were set into oral cavity of each subjects and adjusted. Then the subjects were allowed to intercuspated with maximal bite force while the pivoting ball in the mid-line moving from anterior toward posterior position. The displacement scales were recorded by CCD camera(Sony, CCD-TR-705) and VCR, The conclusions were as follows : 1. When the subject was allowed to bite the metal pivoting ball in the midline of lower dentition with maximal bite force voluntarily while moving from lower central incisor to canine, 1st premolar, End premolar, 1st molar and 2nd molar. The lever actions on the pivot were revealed in all subjects. The equilibrium of moment were revealed on the pivots of 1st premolar(14 subjects), End premolar(4 subjects), and canine(2 subjects) areas. 2. The changes of loading on the TMJ according to antero-posterior positional changes of metal pivoting ball were able to recognize as follow. Compression on the TMJ was increased when the pivot moves anteriorly from the equilibrium point, and tension on the TMJ was increased when posteriorly. 3. 13 subjects were recognized their habitual chewing sides(Rights, Left8), and 7 subjects were not. During maximal biting, mandible was displaced toward their habitual chewing sides on the metal pivoting ball in the frontal plane. 4. In cephalometric analysis, the average genial angle of 20 subjects was $116.75^{\circ}$ and the average mandibular body length was 79.77mm. The equilibrium points of mandibular moment were positioned more posteriorly in the subjects having larger Genial angle than in the smaller(p<0.05). Relationships among the angle between FH plane and occlusal plane, the angle between occlusal plane and mandibular plane , and mandibular body length were not significant(p>0.05).