Unidirectional internal thread with 30˚ wedge ramp

Paul Boughton

Spiralock Corporation has re-engineered the standard internal (female) thread form and added a unique 30° wedge ramp at the root of the thread.This unidirectional internal thread form, called Spiralock, mates with standard 60° male thread fasteners.

The thread design allows the bolt to spin freely relative to the female threads until torque is applied. At that point, the crests of the standard male thread form are drawn tightly against the wedge ramp, eliminating radial clearances and creating a continuous spiral line contact along the length of the thread engagement, which allows a more even load distribution and improves integrity of the threaded joint.

Through its design, Spiralock thread form is exceptionally resistant to thread loosening and stripping, caused by transverse vibration. Furthermore, by elimination of secondary locking devices, ease of assembly, reusability and overall dependability, Spiralock reduces overall costs of threaded joints and solves fastening problems across many industries, with applications including space shuttles and military aircraft, diesel engines, trucks, automobiles, agricultural and construction machinery, oil exploration equipment, railway, medical implants and devices, appliances and others.  

Spiralock Corporation is based Madison Heights, MI, USA. www.spiralock.com


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