Dr.-Ing. Hans-Albert Staedler
Customer Engineering Director Europe
Howmet Fastening Systems Industrial Products, Telford, UK
Howmet Fastening Systems Industrial has many years experience in mechanical fastening technologies. Louis Huck (the founder of Huck fasteners) developed in last century in the middle of the forties the very first lock bolt system. The functionality of lock bolt systems is based on cold forming/ extrusion technology. A so called collar gets cold formed during installation by an anvil (part of a special installation tool) into unique locking grooves of a pin. After the installation the fastener is mechanical locked due to this volume controlled swaging process. The locking grooves are more times filled with collar material. The system of this builds a natural barrier against vibration and clamp loss. Lock bolt systems create vibration resistant and high fatigue life joints. Since the very first lock bolt these systems have been permanent optimized. A revolution was, when Howmet Fastening Systems Industriel came to the market with pintail less lock bolts. These systems do not more have a pintail end with blank and rust effected surface. The installation gets faster, smoother and with reduced noise compared with traditional lock bolts and much faster than conventional bolts.
Germans highest construction authority DIBt tested the Bobtail® in accordance with the EN 1993 regulation and approved it as opportunity to generate total maintenance free joints so far correct installed and the work pieces do correlate with. The Bobtail® delivers also the performance of ISO 12944 C5 M corrosion protection.
The table 1 shows the evolution of lock bolt systems comparable with high strength conventional bolts...
