マルナカ List of Products and Services

The "W-V-LOCK Yurumanzō New Model" employs a ratchet mechanism between the bolt, nut, and washer, and additionally features protrusions on the bottom surface of the washer that bite into the workpiece, successfully eliminating loosening almost permanently. This product is the new model of "W-V-LOCK Yurumanzō," in the hex socket bolt (small diameter cap bolt) type. 【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 tightened object in a wedge shape, preventing the washer from rotating. ■ It does not loosen even under strong vibrations or long-term use. ■ If removal of the screw is necessary, it can be removed by applying a slightly higher loosening torque than the tightening torque. *For more details, please refer to the PDF document or feel free to contact us.

• bolt
• nut

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.

• bolt
• nut

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 by 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 tightened object in a wedge shape, preventing the washer from rotating and providing a loosening prevention effect for the entire screw. ■ No loosening occurs even under strong vibrations or long-term use. ■ A high safety and durability loosening prevention mechanism for screws. ■ Patent obtained. * For more details, please request documentation or view the PDF data available for download.

• bolt
• nut

The "Yurumanzo (W-V-LOCK)" is a safety bolt and nut that successfully eliminates loosening permanently by employing a ratchet mechanism between the bolt, nut, and washer, and by 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 any loosening for over 17 minutes. 【Features】 ■ The bolt and washer are connected using a ratchet mechanism, with several protrusions on one side of the seating surface. ■ The protrusions bite into the clamped object in a wedge shape, preventing the washer from rotating and providing a loosening prevention effect for the entire screw. ■ No loosening occurs even under strong vibrations or long-term use. ■ A high safety and durability loosening prevention mechanism for screws. ■ Patent obtained. * For more details, please request documentation or view the PDF data from the download. * If you would like a sample, please contact us.

• bolt
• nut

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 by 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 tightened object in a wedge shape, preventing the washer from rotating and providing a loosening prevention effect for the entire screw. ■ Does not experience loosening under strong vibrations or long-term use. ■ A high safety and durability loosening prevention mechanism for screws. ■ Patent obtained. *For more details, please request materials or view the PDF data from the download. *If you would like a sample, please contact us.

• bolt
• nut

Marunaka Co., Ltd. is a company that has established a comprehensive production system centered on metal pressing as its core technology, covering everything from mold design and manufacturing to parts processing (pressing, welding, cutting, polishing, and cathodic electrodeposition coating) and assembly. It manufactures automotive parts, office equipment parts, household parts, and more. The company aims to enhance the sophistication of molds, which influence the precision and labor involved in pressing, by having a dedicated section for mold design and manufacturing within the company. It is committed to improving pressing processes through innovative mold designs. Additionally, by conducting the entire process in-house, the company enhances its ability to respond to QCD (Quality, Cost, Delivery) and strives to supply higher quality parts at appropriate prices quickly. It is also advancing research and development of original products. **Main Products and Categories** - **Automotive Parts**: Car air conditioning parts, steering parts, chassis parts, motor parts - **Office Equipment Parts**: Disk steel parts, chair parts, cabinet parts, partition parts - **Household Parts**: Battery parts, earth parts, oven range parts, rice cooker parts *For more details, please refer to our catalog or feel free to contact us.*

• Mold Design
• Press Dies
• Processing Contract