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Structure & Function

The FUJILOK U-NUT introduced the industry's first "Metal ring locking function".
The FUJILOK U-NUT sparked a revolution in the area of bolts and nuts where up until that point loosening had been considered unavoidable.
since its creation over 50 years ago.
The FUJILOK U-NUT is now highly regarded as the first name in locknuts across all industries from steel structures such as railways and connecting bridges to automobiles, motorcycles, and on up to industrial machines.
[Locking effect] created by the friction ring
When the FUJILOK U-NUT is tightened onto the bolt, the friction ring comes into contact with the thread portion of the bolt.
As the nut is tightened further, the friction ring begins to bend along with the screw thread and presses against the shaft screw threads.
A spring effect produced by the friction ring (P), along with a reactionary force that pushes against the screw flank surface (P'), generates prevailing torque (frictional torque) and demonstrates the locking function.




"FINE U-NUT" can be positioned arbitrarily and appropriately regardless of whether it is a toothed washer, and torque management is easy. An epoch-making lock nut for bearings that does not require shaft keyway machining or toothed washer mounting technology. It improves the rotational balance of bearings that generate the "force" of all industrial machinery. In addition, we have achieved a reduction in equipment rotation loss and a reduction in power consumption.
[Locking effect] created by the friction ring

When "FINE U-NUT" is screwed onto a shaft, the friction ring comes into contact with the shaft thread. As the nut is tightened further, the friction ring begins to bend along with the screw thread and presses against the shaft screw threads.
A spring effect produced by the friction ring (P), along with a reactionary force that pushes against the screw flank surface (P'), generates prevailing torque (frictional torque) and demonstrates the locking function.
Reasons why FUJILOK U-NUT・FINE U-NUT is chosen
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Fastening function
Demonstrates stable locking function.
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Dropout prevention
Demonstrates stable locking function.
Effective even at the intermediate position of the bolt -
Reusability
Can be reused with the function of prevailing torque
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Simple fastening
The FUJILOK U-NUT is easy to install, just like general nuts.
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Simplex parts
It demonstrates a locking effect by itself.
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Heat and cold resistance
An all-metal product with excellent resistant to heat and cold,and is not affected by heat.
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Various shapes
Various shapes are available, such as CAP type U-NUT and weld type U-NUT.
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Variety of sizes and types
Thread size of FUJILOK U-NUT is M3-M115, FINE U-NUT is up to M8-M150
*Standards are Metric, Whit, and Unified -
Special product production
We can also manufacture special shapes upon request.
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Cost reduction
Machining, parts management, and fastening technology are unnecessary.
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Balance
(FINE U-NUT)Improves the rotational balance of shafts and bearings.
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Weight reduction
(FINE U-NUT)The number of parts can be reduced. It allows for the use of hollow shafts that are thinner than normal.