As mentioned , BobTail ® fasteners are a two-part fastener , they consist of a headed pin and a collar . The BobTail ® pin is made with a series of pulling grooves at its tail end . The installation tool ( driven by pneumatic , hydraulic or battery power ) grips onto these grooves , pulls the work together , then the conical shaped cavity of the nose assembly is forced down the collar which is axially pressed firmly into the grooves of the pin by the processing tool . At this stage of the installation the tool has progressively cold formed ( swaged ) the collar into the grooves of the harder pin . The squeezing action reduces the diameter of the collar , increasing its length . This stretching of the pin and collar generates the clamp force over the joint . The pin and swaged collar combine to form the installed fastener providing a permanent and completely vibration resistant joint .
Installation is quick ; typically , less than two seconds per fastener , and unlike traditional LockBolts ® no pin-break is required , therefore leaving no corrosion-prone area of bare metal or spent mandrels to be collected . This direct metalto-metal contact of the collar swaged into the grooves of the pin eliminates the loosening effects of transverse vibration .
The setting process is complete with the deformation of at least one of the six indicators ( on sizes 12mm / 1 / 2 ” diameter and above ) on the flange of the formed collar . In the case of collars without indicators ( on sizes 9.5mm / 3 / 8 ” diameter and below ), in all diameters , a ring gauge check can be performed to check the installation procedure . Also available is a colour changing collar which shows a distinct visual difference between an installed or an uninstalled fastener .
Swage indicator on a Huck ® Collar
Lockbolt ® installation sequence ( BobTail ® )
1 2 3 4
Once installed , the fastener will perform consistently for the lifetime of the joint without requiring checking or retorquing .
Recognising the cost associated with assembly time , BobTail ’ s ® installations are fast , smooth , low noise and shock free ( no jolts or vibrations on the operator ’ s hands and arms ). The time saved by utilising BobTail ® fasteners is significant when considering the large number of potential fastening points . It could be argued that the cost of the BobTail ® fastener and installation tools are more than those of a nut and bolt , but when considered , the high fatigue strength of BobTail ® fasteners means that fewer are needed , joint integrity is not compromised , and overheads are quickly saved in other areas . Post-installation Huck ® BobTail ® only requires a quick visual inspection ( no torque , therefore no re-torque is required ), saving even more time and expense . In addition , Huck ® BobTail ® fasteners have been designed to be tamper-proof for an additional measure of security .
Huck ® BobTail ® fasteners are a cost-effective fastening solution for industries and applications where reducing labour and installation costs is essential . A combination of quick , straight forward installation and long-term reliability make them a preferred choice for many professionals looking to optimise both time and budget resources .
The pin is inserted into the prepared hole , and the collar is spun onto the pin . |
The installation tool is applied to the annular pull grooves . When the tool is activated , a puller in the nose assembly draws the pin into the tool , causing the swaging anvil to press on the collar , drawing up any sheet gap . |
At a predetermined
force , the anvil begins to
swage the collar into the
pin ’ s lockgrooves .
Continued swaging
elongates the collar and
pin , developing precis * clamp .
When swaging of the
collar into pin
lockgrooves is complete ,
the tool ejects the
fastener and releases the
puller to complete the
sequence .
Based on a typical installation of 5 / 8 " grade 8 fastener
|
Star Fasteners are Huck ® fastener experts and the UK ’ s largest Huck ® fastener distributor . We work globally with a diverse range of end users and distributors from across a number of industries , offering technical application knowledge and customer support . Huck ® fasteners guarantee performance and help maximise return on investment ; get the right fastener for your project and achieve your business goals . With many added value services and years of product application knowledge , Star Fasteners are able to offer a unique customer experience . |
For more information call us on + 44 ( 0 ) 115 932 4939 or email sales @ starfasteners . co . uk
20 PECM Issue 66