Successfully eliminated loosening permanently with safety bolts and nuts! Passed JQA high-speed vibration loosening test!
The "Yurumanzo (W-V-LOCK)" is a safety bolt and nut that successfully eliminates loosening permanently by adopting a ratchet mechanism between the bolt, nut, and washer, and further incorporating protrusions on the bottom surface of the washer that bite into the workpiece. All five units tested in the vibration loosening comparison test conducted by the Japan Quality Assurance Organization passed without loosening for over 17 minutes. 【Features】 ■ The bolt and washer are connected using a ratchet system, with several protrusions on one side of the seating surface. ■ The protrusions bite into the fastened object in a wedge shape, preventing the washer from rotating and providing a loosening prevention effect for the entire screw. ■ Does not loosen even under strong vibrations or long-term use. ■ A loosening prevention mechanism with high safety and durability. ■ Patent obtained. *For more details, please request materials or view the PDF data available for download.
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basic information
"Outstanding performance in vibration loosening tests according to NAS3350 standards" ○ High-speed screw loosening test conditions: (100,000 cycles, 17 minutes) ○ Frequency: 1,780 rpm ○ Excitation table: 11 mm ○ Impact stroke: 19 mm ○ Vibration direction: Perpendicular to the bolt axis ○ No torque reduction even with the return torque after testing ● For more details, please contact us or download the catalog.
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Company information
Marunaka Co., Ltd. has established a consistent production system centered on metal pressing as its core technology, encompassing everything from mold design and manufacturing to parts processing (pressing, welding, cutting, polishing, and cathodic electrodeposition coating) and assembly. The company manufactures automotive parts, office equipment parts, and household parts, among others. In particular, it focuses on enhancing the sophistication of molds, which significantly affect the precision and labor involved in pressing. Marunaka has a dedicated section for mold design and manufacturing, working on improvements in pressing processes through innovative mold designs. By conducting all processes related to metal press parts, including molds, in-house, the company enhances its ability to respond to QCD (Quality, Cost, Delivery) requirements, striving to supply higher quality parts at appropriate prices and with speed. Additionally, leveraging the accumulated know-how from metal pressing, Marunaka is advancing research and development of original products, such as the "W-V-LOCK" bolts and nuts that do not loosen under strong vibrations. As a technical group specializing in metal press parts, Marunaka Co., Ltd. is committed to skill enhancement, upgrading equipment, and strengthening its integrated production system to meet customer demands at a high level.