Thanks to the drive concept consisting of converging surfaces and the special geometry between the screw head drive and the bit (drive tool), we were able to combine three key requirements: axial alignment, maximum contact area and a firm hold of the screw by the bit. The combination of these properties makes it easier to perform overhead jobs and screw in components or parts in inaccessible locations, and facilitates automated screw driving processes.
Axially aligned self-fixing screws
The system self-aligns axially as the bit is inserted into the screw head. This is an advantage in robotic screw driving systems with automatic screw feeding and in critical applications where it is important not to damage the screw or nut thread. The converging surfaces ensure that the screws cannot fall out of the bit, thus greatly facilitating overhead working. No additional spigot, for instance, is needed below the bit to align the screw axially (see diagram of contact area).
Compared to an internal hexalobular (TX bit), tensions are considerably reduced in the TOBI® bit thanks to the approximately ten times larger contact area. As the load on the screw tool is reduced significantly, TOBI® bits offer an exceptionally long tool life. Compared to a piloted internal hexalobular bit, more of the tool penetration depth can be used for torque transmission.
More contact area than ever before!
The load on the bit is much reduced thanks to red-highlighted contact area (Ac) between the TOBI® screw head profile and the bit, which is far larger than to all other systems. The special design increases tool life significantly, which helps to reduce costs.
Compatible with hexalobular-round (TX) and AW bits
Due to the slightly larger opening of the drive profile in relation to the Internal-6-lobe (TX) and AW drive, the respective TX or AW bits also fit in screws with TOBI®-DRIVE-SYSTEM.
In this way, TOBI® screws can also be dismantled and screwed back in for service purposes using commercially available TW and AW bits. The availability of corresponding TOBI® bits at the user side is therefore not a mandatory requirement for the use of TOBI® screws.
SCREW HEAD AND DRIVE LOAD COMPARISON
Thanks to the exceptionally minimised load achieved by the innovative TOBI® DRIVE SYSTEM, in most use cases constant tightening torques can be maintained with much smaller drive sizes and/or shallower penetration depths. If this advantage is taken into account in the structural design of a screw connection, screws with much smaller head diameters and heights can be used. Benefits arising from weight and raw material savings, not to mention completely new installation possibilities for narrow spaces, are thus generated. Last but not least, TOBI® helps design engineers to comply with sustainability requirements. The diagram on the left shows a FEA model with a tightening torque of 10 Nm and 22 Nm respectively (based on strength class 8.8).