• Journal of the Korean Society of Safety
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• v.26 no.2
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• pp.1-5
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• 2011

In order to evaluate fatigue endurance for an ultra-light weight inline skate frame, FEM analysis was performed. Tensile properties and a S-N curve were determined through tensile and fatigue tests on a modified Al-7075+$S_c$ alloy. The yield and ultimate tensile strengths were 553.3 MPa and 705.5 MPa, respectively. The fatigue endurance limit of this alloy was 201.2 MPa. For evaluating the fatigue endurance of the inline skate frame, the S-N data were compared with the stress analysis results through FEM analysis of the frame. The maximum Von-Mises stress of the frame was determined 106 MPa through FEM analysis of the frame, assuming that the rider weight is 75 Kg. Conclusively, on the basis of fatigue limit, the inline skate frame has a safety factor of approximately 2.0.

• Korean Journal of Computational Design and Engineering
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• v.10 no.1
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• pp.17-26
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• 2005

In-line skate generally consists of four major parts: boot, frame, bearing and wheel, and the most important part among those for necessary functionality is the frame. It is the most expensive, and it also makes a decisive role in practical race skating. The functional behavior of a frame is greatly affected by external dynamic forces as well as the static weight of a skater. We are proposing a new inline speed-skating frame design that has been improved in structural strength and weight for providing optimum speed in $20\sim40km$ marathon skating.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1507-1514
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• 2011

Injection molding is the most commonly used process that uses plastic material. Today, the uses of plastic material are continuously increasing, and the range of application is also being extended by the development of novel materials. An inline skate consists of 4 components: the boot, frame, wheel and brake. Among these components, the frame is the most critical. The injection formability for a variety of injection materials for inline skate frames was studied. We also studied the injection formability of the product for various sizes of the runner and gate. In this study, injection molding analysis was performed using MOLDFLOW, and structural analysis was performed using ANSYS.

• Korean Journal of Applied Biomechanics
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• v.15 no.2
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• pp.11-20
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• 2005

This study has a purpose on contributing to apprehend safe and right way to stop to the inline skate beginners and to the instructors who teaches line skating on the basis for the result of the kinematical analysis on Heel brake stop movement of the inline skate, focusing on the displacement on COG, angle displacement of ankle joint, angle displacement of knee joint, angle displacement of hip joint, using a 3D image method by DLT. To achieve this goal, we analysed the kinematical factor of the 3 well-trained inline skating instructors and obtained the following results. 1. During the movement of heel-brake stop, when strong power was given to a stable and balanced stop and the lower limbs, if the physical centroid is lowered the stability increases, and if it is placed high from the base surface, as the stability decreases compared to the case of low physical centroid, we should make a stop by placing a physical centroid in the base surface and lowering the hight of physical centroid. 2. To make a stable and balanced stop and to provide a strong power to the lower limbs, it is advisable to make a stop by decreasing an angle displacement of ankle joint during a "down" movement. In case of the left ankle joint, in all events and phases the dorsiflexion angle showed a decrease. Nevertheless, in the case of the right ankle joint, the dorsiflexion angle shows an increase after a slight decrease. The dorsiflexion angle displacement of ankle joint can be diminished because of the brake pad of the rear axis frame of the right side inline skate by raising a toe, but cannot be more decreased if certain degree of an angle is made by a brake pad touching a ground surface. To provide a power to a brake pad, it is recommended to place a power by lowering a posture making the dorsiflexion angle of the left ankle joint relatively smaller than that of the right ankle. 3. To make a stable and balanced stop and to add a power to a brake pad, the power must be given to the lower limbs in lowering the hight of physical centroid. For this, it is recommended to make a down movement by decreasing the flexion angle of a knee joint and it is necessary to make a down movement by a regular decrease of the angle displacement of knee joint rather than a swift down movement in every event and phase. 4. The right angle displacement of hip joint is made by lowering vertically the hight of physical centroid as leaning slightly forward. If too narrow angle displacement of hip joint is made by leaning forward too much, the balance is lost during the stop by placing the center in front. To make a stable and balance stop and to place a strong power to the lower limbs, it is recommendable to make a narrow angle by lower the hip joint angle. However, excessive leaning of the upper body to make the angle too narrow, can cause an instable stop and loss of physical centroid. After this study, it is considered to assist the kinematical understanding during the heel brake stop movement of the inline skate, and, to present basic data in learning a method of stable and balanced stop for the inline skating beginners or for the inline skate instructors in the present situation of the complete absence of the study in inline skating.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.2
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• pp.289-295
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• 2010

Injection molding process is one of the most important methods to produce plastic parts with high efficiency and low cost. Today, injection molded parts have been increased dramatically the demand for high strength and quality applications. In this study, In-line skates are made of Al alloy and plastic materials to replace the frame for the optimization process is all about. I interpreted through mold design, Injection molding process that minimizes the runner and the gate dimension will determine the size and shape. Runner and gate dimensions of change based on availability of the product, I'll discuss the injection molding. This report investigates that the optimum injection molding condition for minimum of shrinkage. The FEM Simulation CAE tool, Moldflow, is used for the analysis of injection molding process.