Thong diapers and beerbrellas: US patent office celebrates some of its most bizarre applications

Unless you belong to the insular and wonkish world which is obsessed with patent law and intellectual property, an upcoming milestone might escape you: the US Patent Office is on the verge of issuing its nine millionth patent.

The agency issued its most recent posted patent, US 8,990,961 B2, on March 24.

So after the monumental task of narrowing it down to a select few, here are some of the most bizarre and improbable patents ever issued.

- This one is self-explanatory. It's a thong that is also a nappy. The Brooklyn woman who filed for a patent in 2005 leaves the device's possible uses to the imagination, claiming only that it is an "ornamental design for a thong diaper".

- Possibly inspired by everyone's favourite lover of fava beans and chianti , this apparatus involves strapping a "cup-shaped member" made of rigid wire over the mouth and chin, and locking it in place behind the head with leather straps.

- A twin feat of marketing and relaxation, this "novelty accessory" is described as a 12cm-18cm umbrella that users can attach to beverages - even those which are not beer, so long as they are in bottles - in order to keep them cool. The plans said the umbrella would first be made with plastic, with the possibility of adding a more high-end cloth model down the line.