Do you recognize how much innovation is behind the simple pleasures of life like a carbonated beverage? A great deal of clever physics and science has gone into the subtle innovations that allow us to enjoy these beverages without, say, risking blindness every time we open a bottle of Sprite. In the early days of soda innovation, there was some risk in opening a screw-top container because the pressure was locked in by the interconnected threads until the screw cap came off: then the high pressure in the container could propel the up and away. Packaging engineers tacked the problem, leading to the first big breakthrough described in a 1961 patent, “Gas Escape Closure Cap” by Leo Garvey, US Patent No. 2,990,079. There were other earlier solutions proposed, including more complex venting caps, but the solution of grooves in the threads is elegant. Part of the patent is shown below, where in the lower right-hand corner you can see a drawing showing grooves in the ridges of the threads of a cap that help allow pressurized gas to escape while the bottle is being opened. A variety of later patents build on that theme, with 21 different patent families citing the Garvey patent. Today grooves in the threads of the bottle are also used, as shown, for example, in US Pat. No. 4392055 of Owens Illinois, providing the same kind of safe venting that Garvey sought. (That also reminds us of the need to consider alternative solutions in pursuing patent coverage.)
Gas venting threads are a tiny tweak of the bottle design that many people overlook, but they play an important role. There are numerous subtle innovations in almost every aspect of the soda bottle, from the design of the flange, the materials use to make it, the shape of the foot of the bottle allowing it to stand without the need for a separate stand or ring, the attachment of labels, the design of the cap, and the basic bottle manufacturing process itself. It’s all worth a toast the next time you have a sip. Innovation adds fizz to our daily lives–and safety.