The core idea here is a modified drill chuck (the ones where you turn it and three prongs slide in or out to grip the drill bit) where the prongs each have a 120° angle inside and outside. What you do is either use the inner surface to grip hex nuts or the outer and use it like an allen wrench for hex screws.

The non-business end has two circular holes cut in to it, one along and one at right angles to the main axis. These have a slot along one side, and a circular opening at the end (like a tumbler lock). The tool's handle is inserted here and turned 90° like a key, so it stays locked in the slot. the vertical slot lets the tool be used like a scrwdriver, the horizontal one like a wrench.
-- Aegis, Aug 14 2004

Unbrako http://www.unbrako.com/
Better strength to mass than Ti fasteners. So if you want lightness design with these. [eight_nine_tortoise, Mar 20 2009]

The allen key version of the adjustable spanner!
-- cindik, Mar 20 2009


The trouble with this is that you often need the full torque that only a fully dense hardened shaft can give you. Expecially when using super strength screws such as Unbrakos [link], or trying to undo screws with loctite and corrosion. So anything with moveable prongs is likely to get bent the first time you lean on it [-].
-- eight_nine_tortoise, Mar 20 2009


It's gonna be tricky to get this into tight spaces, but sounds useful to me!
-- Skrewloose, Mar 20 2009


Excellent idea! Don't know if it's bakeable but definitely a killer concept. +
-- placid_turmoil, Mar 20 2009


I agree with the torque problems mentioned above, but [+] for the 90% of bolts I come across this would help with.
-- Srimech, Mar 20 2009


hex head hardware us frequently used in low clearance mounting points where the use of a conventional head for later R&R is not possible or very inconvenient. I can't think of many situations where a bulky hex key would be useful. In concept I can imagine it working, even using a simple cam action to spread three dogs that would grip the hex as you applied torque, but in application I have broken enough keys to know that even a solid shaft is sometimes inadequate.
-- WcW, Mar 20 2009



random, halfbakery