• The Journal of Korea Robotics Society
• /
• v.6 no.1
• /
• pp.10-17
• /
• 2011

This paper deals with researching and designing the fastening parts to be used in order to assemble various Teaching Aids Robots (or Hands-on Robots) with originally incompatible parts supplied by different manufacturers. The suggested fastening parts provide the compatibility among Teaching Aids Robots even though the educational robot customers use incompatible parts from different companies. The designed fastening parts are classified into four set groups such as frame set, sliding-bar set, connector set, and set of chuck and rivet/bolt. Each set of the fastening parts reflects the needs collected from the users, and then some portion of new idea has been added to implement the needs. In this paper, the examples of the Teaching Aids Robots which are assembled with both commercial parts and the designed parts are presented in order to evaluate the compatibility and usability of the suggested fastening parts. As a result, both compatibility and usability of the fastening parts suggested in this paper were proved. The designed fastening parts have been distributed to more than 100 elementary schools nationwide.

• Journal of Applied Reliability
• /
• v.11 no.3
• /
• pp.305-318
• /
• 2011

In the statement of logistics reliability prediction methodology, all components should be managed as the analysis objectives. However, in some reliability prediction of weapon systems, fastening parts, e.g., screws, bolts and nuts, have been frequently ignored because some organizations related to weapon systems have emphasized that those parts are not significant in their failures rate and functions. In this paper, failure rates, modes, and distributions were presented to prove that fastening parts should be included in reliability prediction objectives. Also, failure rate prediction methods of fastening parts are presented and compared.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.2090-2100
• /
• 2011

Railway rail fastening system is the critical device which gives big influences to not only the vehicle driving stability and the orbit's structural stability against the impulsive load, but also the noise vibration and the ride comfort. As a part of the low-carbon green growth, the importance of the railroad industry is getting highlights on its excellent energy-efficiency and eco-friendliness. However, so far the Korea's domestic rail fastening system technology is not so good and the technical reliance to abroad is very heavy. In this study, we conducted comparative analysis on the rail fastening system with new and used one of the same type. And those systems are imported by Seoul Metro and are being used by it. With this basis, we developed the components and the materials and then, established the durability assessment methods appropriate to the Korean domestic circumstances. And through the reliability qualification test on the 7 parts of the rail fastening system, we've improved the reliability and guaranteed the 15 years of service lifetime. ($B_{10}Life15$) Establishment and standardization of Reliability Standard on the parts of the rail fastening system such as anti-vibration pads, guide-plate, screw spike made it possible to perform the internationally fair assessment. And it is thought that we can satisfy the manufactures' and consumers' needs of cost-cutting and qualification security by shortening of assessment period on rail fastening system.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.17 no.2
• /
• pp.187-192
• /
• 2009

A snap ring is a kind of metal spring with open ends which can be installed into a groove to prevent lateral movement. In this study a nonlinear finite element analysis model is developed to simulate the fastening process of a snap ring connecting the constant velocity joint and the transmission. Insert load, disengage load and breakage are three important issues. They are analyzed using the developed model. The load histories of simulations are similar to those of tests and the differences of maximum load are around 10%. Bending of the entire ring and unfolding of the end section are major contributors of the fastening load. The load variations caused by the angular position of spline tooth are about 50%. Breakage is highly sensitive to the position of a snap ring.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.04a
• /
• pp.561-566
• /
• 2000

A screw driver is essentially used in assembling machine parts and electronic products such as the printed circuit board with a housing. As the parts to be assembled becomes small and precise, the higher precision of the controling screw driver torque is required. However, because the operator controls the fastening torque by his experience, it must be inexact. Thus the screw driver which can exactly control the fastening torque by a bellows is designed and developed in the study. The bellows is expanded by the inner air pressure and contracted and by the spring operation. The bellows driver is composed of the entrance solenoid valve, the exit solenoid valve and the pressure sensor. The pressure sensor senses the bellows pressure. When the pressure sensor output reaches the setting value, it operates the exit solenoid valve not to deliver further torque by letting the air of the bellows out. Through a series of experiments, the performance is studied and verified.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.10 no.5
• /
• pp.53-59
• /
• 2001

A screw driver is widely used in assembling machine parts or electronic products such as the printed circuit board with a housing. As the parts to be assembled becomes small and precise, the higher precision of the controlling screw driver torque is required. However, because the operator controls the fastening torque based on experience, it must be inexact and the setting procedure will be time consuming job. Thus the screw driver which can exactly control the fastening torque is developed utilizing a bellows in this paper. The bellows is expanded by the inner air pressure and contracted by the spring operation. The bellows type driver is composed of a clutch mechanism with two solenoid valves and a pressure sensor. Those valves are controlled using the detected bellows pressure by the sensor. When the pressure reaches the setting value, the exit solenoid valve is opened to release the air pressure from the bellows so as not to deliver further torque. Through a series of experiments, the performance is examined and verified.

• Journal of the Korean institute of surface engineering
• /
• v.48 no.3
• /
• pp.93-99
• /
• 2015

This test focuses on the correlations between joining axial force at non-room temperature and at room temperature according to the surface treatment (Geomet, Dacro, Green Kote, Armore Galv.). The quality characteristics of the fastening axial force required by the KSB 2819 and EN14399-10 standards were discussed. Surface treatment was implemented to S10T and 10.9HRC sets of bolts under the same environmental factors. Development for the stabilization of the fastening axial force required by each standard should continually be enforced, and the fastening and storage in the field should be maintained at room temperature. Managing stabilization of torque enumerated data is required after application of surface treatment. It is concluded that, by conducting the test of applying surface treatment to effectively manage, each lot-specific rate of axial force at room temperature conditions should be maintained below the maximum 4.47%. The decline rate of axial force should be maintained under 2.15% maximum, and the standard deviation of the room temperature condition should be maintained below 0.5.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.1
• /
• pp.112-119
• /
• 2009

The mechanical fastening has some advantages in respect of the fastening strength and disassemble of the fastened parts. However, at the same time it has some dangerous factors, can cause fatigue crack initiation and propagation due to not only the static loading such as cargo and passengers but also the dynamic loading like vibrations which occur in the engines and the propellers. For this reason, the strength evaluation for the mechanical fastenings along with the sophisticated and detailed mechanical design and the safety evaluation should be executed, In this paper, we were carried out experiments to study fatigue crack growth paths in structures containing the multiple circular holes. It was investigated that how circular holes are affected on fatigue crack growth paths using the specimen consists of A5052-H112, which is widely used as the ship materials. It was found from the experimental results that the fatigue crack as if it is drawn to circular holes when crack tip approach to circular holes. However, it did not go into circular hole if there is the next circular hole. Therefore, the clarification of mechanism on the fatigue crack initiation and the propagation in structures containing the multiple circular holes can be expected in this study.

• Transactions of Materials Processing
• /
• v.28 no.5
• /
• pp.266-274
• /
• 2019

Metal sealing is used to connecting the parts between valves and fuel pipes for a FCEV which utilizes hydrogen gas of 700 bar. Instead of general carbon steel, stainless steel is the primary material used to manufacture fuel pipes due to hydrogen embrittlement. The shape of deformation between metals is an important factor on the air-tightness of the metal to metal contact. Since the stainless steel pipe is hardened using the plastic forming during the tip shaping stage, this work hardening could have an effect on the deformed shape and characteristics of contact surfaces in fastening of pipes. In this paper, the deformation history of the pipe model was considered in order to analyze the hydrogen-tightness on the metal sealing part. The contact distance and the forward displacement for fastening were compared using experimental results and the simulation results. The simulation of the effect of material change on the fitting body demonstrated that the hardness or the strength of the formed tip of the pipe was designed to a proper valued level since the characteristics of the contact surface was exhibited better when the strength of the pipe was lower than that of the fitting body.

• Proceedings of the KSR Conference
• /
• 2006.11b
• /
• pp.508-513
• /
• 2006

Anchor bolt in baseplate fastenings on the slab track is an important component to conform placing and safety of fastenings. Due to the way of load transmission control of fastenings, sometimes anchor bolt has to be applied lateral load. So we have to take care for it when we design. Especially, in the case of anchor bolt which is applied loads repeatedly, we have to consider fatigue failure. If parts of machine are damaged in static loads, stress will exceed the yield strength. So parts could be transformed largely. Therefore because they are visible to the naked eyes, we can replace parts before failure. However, because fatigue failure that are invisible to the naked eyes happen unexpectedly, it's very dangerous. To make a reasonable design of anchor bolts, we will analyze them by changing diameters of anchor bolt, quality of insert, initial gap between anchor bolt and insert, the presence of insert, etc. which affect the stresses of anchor bolts. We can get the maximum and minimum amplitude of stress through the modified Goodman diagram or Smith diagram which represents limit of all strengths and stress components to the average stress. We also tried to show the way of examining the expected th life of anchor bolt briefly through considering above.