Technical
Couplings that can be connected and disconnected in seconds without tools are taken for granted today – on machine tools, in hydraulics, in medical technology and in every workshop. But it was a long way to get there: from the thread via the fire hose coupling to the leak-free, standardised high-tech connection.
Industrialisation brought steam engines, pressurised water and gas lines. Almost everything was connected via threads: pipes and hoses were screwed together – reliable, but slow. Anyone wanting to change a line needed tools, time and often new sealing material. As hoses became more widespread, the demand grew for a connection that could be made and released more quickly.
Fast coupling was particularly urgent for fire brigades: every second counts in an emergency, and hoses from different brigades had to fit together. In 1882 the architect Carl August Guido Storz developed a symmetrical coupling with no "male" and "female" side that locks with a quarter turn. It was patented in Switzerland in 1890 and is still the standard for fire hoses in large parts of Europe today. This proved that a quick connection can be safe, tight and standardised.
Fred Hansen is regarded as the inventor of the industrial quick-release coupling. In 1915 he founded the Hansen Manufacturing Company in the USA and launched a coupling that could be connected simply by plugging it together and released again with one movement. The basic principle – a plug (nipple), a socket (coupling) with locking mechanism and shut-off valves that close on disconnection – still characterises quick-release couplings today.
In the following decades compressed air tools became established in industry and trade. Screwdrivers, drills and spray guns had to be reconnected constantly – ideal for the new technology. Numerous designs with ball locking and sliding sleeve emerged that shut off automatically on disconnection. In the 1950s in particular, many new designs were patented that significantly improved handling, tightness and flow.
With the mechanisation of agriculture and construction, the demand for hydraulic couplings grew: tractors, implements and construction machinery had to be connected quickly and safely – at pressures of several hundred bar. The couplings were made of steel, with robust valves and seals that withstand the high pressure. Because each manufacturer used its own dimensions, equipment often did not fit together – the call for standards grew louder.
With the triumph of plastics in the second half of the 20th century, injection moulding became a key technology. Injection moulds have to be precisely temperature-controlled via many cooling circuits – with water or oil, often at high temperatures. Quick-release couplings are what make mould changes economical. Different countries developed their own coupling profiles, which still exist side by side today – such as the European profile, the French profile and the international profile. At FLEXQ these include the HPT, MPT and IPT series.
The more circuits a mould has, the longer it takes to reconnect – and the greater the risk of mixing up supply and return. The solution is multi couplings: plates that connect all circuits simultaneously with one movement. The machine side stays on the machine, the mould side on the mould. This saves a lot of time during mould changes, prevents mix-ups and is the basis for automated quick-change systems.
At the end of the 1970s the first plastic couplings with push-button locking came onto the market – lightweight, corrosion-free and operable with one hand. Instead of pulling back the sleeve, you simply press a button. This design conquered medical technology, laboratory equipment and chemistry and is now also widespread in industry. FLEXQ offers push-button couplings in the PBW, PBP and PBH series.
With ISO 7241-1, internationally uniform interface dimensions for hydraulic quick couplings were defined for the first time in 1987. The standard describes two series: series A, predominantly used in Europe, and series B, predominantly used in America. Since then, couplings from different manufacturers within a series can be connected to each other. At FLEXQ, the PPT series corresponds to ISO 7241-1 series B.
Conventional couplings lose some medium when disconnected and trap air when connected. For clean, environmentally friendly work – for example on construction machinery or test benches – flat-face couplings with flat front faces were developed. ISO 16028 defined their interface dimensions and requirements in 1999: on disconnection, both sides seal automatically, practically without drips. At FLEXQ this is the HPF series.
Modern quick-release couplings are precision components: they withstand temperatures of over 200 °C, are made of stainless steel for aggressive media, prevent unintentional disconnection with safety locks and can be connected cleanly thanks to flat-face valves. New applications such as liquid cooling of electronics and data centres place further demands on tightness and flow. At the same time, the connection is becoming digital: flow monitoring detects blocked or incorrectly connected circuits before rejects occur.
More than 100 years after the first quick-release coupling, the basic principle has remained the same: plug instead of screw. FLEXQ is taking this idea further – with couplings, multi couplings, collectors and hoses for mould temperature control, hydraulics and many other applications.