The O ring seems to have been around forever, but is still extensively used throughout the engineering world and is still a vital component in many pieces of equipment.
The O ring was first patented in 1937 in the USA by a 72 year old machinist by the name of Niels Christiensen.
He was not originally a US citizen as he was born in Denmark and emigrated to the USA in 1891.
His major claim to fame was the development of an air brake for the streetcars of the USA which he patented.
Whilst this patent went well despite his best legal efforts the patent for the O ring was passed around various US companies before it was finally passed to the major company Westinghouse.
Their hold on it was short lived as the patent was commandeered by the US Government in World War 2 and several companies were given the rights to manufacture as it was considered a crucial item in the manufacture of war equipment.
Mr Christiensen was given the sum of $75,000 in a lump sum for his efforts.
After the war the court cases continued until 1971 when the family was awarded $100,000 some nineteen years after he had died.
Today the O ring has moved on but it is still essential where a joint is required from a flexible pipe to a fixed pipe.
The O ring supplies a pressure around the full ring of the tube and pulls the flexible pipe onto the fixed pipe so that there is no chance of liquid leakage at any part of the circumference.
Originally the O ring was made from fairly cheap materials but these days a good supplier can supply mild steel, zinc plated rings for the lower pressure application and is also able to supply the higher strength models which are made of stainless steel with a T bolt clamp for the higher pressure applications.
ACE who are one of the major manufacturers produce a stainless T bolt clamp which gives a much higher torque setting and is used for applications such as hydraulic, compressors and pumping uses as well as agriculture, irrigation and the motor and plant equipment trade.
A typical O ring with a band width of 18mm and thickness of 0.
6mm made of stainless steel can be tightened to around 6N/m.
The most fascinating thing is that the fastener design has not changed at all since it was developed.