I’m interested to read that even the best bicycle locks are all still vulnerable to attack by angle grinders or disc cutters.
Today’s invention aims to decrease that problem.
It takes the form of a steel spring which can be slipped over the U section of a bike lock, before it is closed around a bike.
The spring has a ‘beard’ consisting of numerous stainless steel wires and kevlar fibres. These are designed to obstruct access to the U section.
More importantly, they act as the fibres in chainsaw-proof clothing do, so that when a rotary cutter blade presses onto the lock, many fibres snag on the cutting edge and wrap themselves around its spindle (and also clog any safety guards). Fibre-loops would probably work best in terms of entangling with the disc.
This jamming makes cutting through the lock significantly more time-consuming.
When cycling, the ‘beard’ can be carried either in situ around the lock or pressed axially inside a tube (like the trunk of an artificial Christmas tree).
Here is another article about various approaches to locking bikes…pretty obvious really.
http://lifehacker.com/5942301/the-proper-way-to-lock-your-bicycle
No mention of the freeze-then-hammer technique. This reminds me that I spent a while working on payphone design in the old days. These had to resist people arriving with a lorry containing a generator and multiple, heavy power tools.