Hardlock nuts utilize a wedge, a technique used in traditional Japanese wooden architecture, to eliminate play in the "fitting thread portion."
 
It consists of two types of nuts, one with a protruding and one with a concave shape. The wedge-shaped, eccentrically machined convex nut, which acts as the tightening nut, is tightened first, and then the perfectly round concave nut, which acts as the locking nut, is placed over it and tightened. This causes the entire threaded portion of the convex nut to be pressed against the bolt, while the entire threaded portion of the concave nut is pressed against the bolt thread on the opposite side.

Hardlock nuts lock completely with nuts that have different textures. Therefore, even when subjected to repeated external forces perpendicular to the bolt axis, which are said to "always loosen any screw fastener," the screw will not rotate backward.
Furthermore, because it can maintain its initial tightening force for an extended period, it is a product with unparalleled performance worldwide.

The bearing nut was developed as a locking nut for bearings.
Its high anti-loosening effect ensures a stable and perfect fastening state, unaffected by vibrations from high-speed rotation or shocks from forward and reverse rotation, enabling significant cost reductions through maintenance-free operation.
 
Furthermore, an innovative application of this technology to hex socket set screws is the self-locking set screw, which is mainly used to secure the casting pins in molds.

Product: Hardlock Bearing Nut

Vertical articulated robots have joints similar to those in human shoulders, elbows, and wrists, allowing them to perform complex movements just like a human arm. Many vertical articulated robots have six axes of articulation, and in principle, six axes are sufficient to cover a full range of hand position and orientation.
The more axes there are, the more different postures can be adopted, increasing versatility.
 
1) Places of employment
- Locations where bearings are fastened with low axial force
- Sections that repeatedly perform forward and reverse rotation movements
 
2) Improvement
- It enabled fastening in areas where smooth movement is required and where low axial force fastening is necessary.
• Maintenance cycles have been significantly extended, resulting in longer operating hours and improved productivity.

Product: Hardlock Nut

The railway tracks on bridges are ballastless (without ballast or slabs), and when a train passes over them, the impact load and vibration from the vehicle are concentrated on the fasteners. Hook bolts are used to secure the sleepers to the bridge girders.
 
1) Places of employment
- Areas that are subjected to impact loads and vibrations from the train
- Railway sleepers are designed to sag to absorb impact, and therefore cannot be tightened too tightly in certain areas.
- The detachment of parts is a dangerous area that could lead to personal injury to people below the bridge.

2) Improvement
- The burden of inspection work during nighttime inspections has been significantly reduced.
• The problem of parts falling due to loosening has been eliminated, resulting in improved safety.

A technical information site about screws in general and loosening.

Engineers facing challenges with screw fastening should obtain specialized technical information, including the following, from "Screw Fastening Technology Navi."
 
- Loose screws
• Design and tightening of screw fasteners
・About screws
Screw troubles
• Download materials