Jonathan Beach, European Director of Product Management at ITT ­Interconnect Systems explores the advances of interconnect ­solutions that are emerging in response to the demands of Mil/Aero system applications

Arguably the most vulnerable part of any electronic system is the connector. Required not only to make electrical contact but also often to provide a physical, sometimes even load-bearing link, the interconnect system sees physical stresses that other electronic components never encounter.

In high reliability (hi-rel) applications the issue becomes even more challenging: systems used for aerospace and defence contracts must survive hostile and demanding environmental conditions where shock, vibration and extremes of temperature are routinely experienced.

Yet the same pressures that apply to commercial applications – size, weight, performance, cost – also apply to hi-rel applications.

Weight is especially critical: to take just two examples, modern soldiers are expected to carry sophisticated electronic equipment into conflict zones, while Unmanned Aerial Vehicles (UAVs) can carry a limited payload.

In order to satisfy such challenging demands, connector makers such as ITT Interconnect Solutions (ITT ICS) have had to come up with innovative solutions 100 percent sealed against harsh environments and addressing the need for increased interconnectivity, solutions. In response, the company developed its Nemesis connectors that provide the fast, reliable signal integrity demanded by C4I (Command, Control, Communications, Computer and Intelligence) systems and other applications in the field.

These connectors suit applications such as portable computers, weapons, vision systems, head sets, GPS equipment and radios. These interconnects are fully-sealed to IP67 or IP68 and are up to 50 percent lighter and 60 percent smaller than comparable 38999 connectors. Profiles have also been reduced, and a ‘Ripaway’ extra-fast decoupling action has been developed for wearable systems.

Ready for action in the line of duty

The devices are constructed from stainless steel for strength and durability, ensuring the connectors remain fully sealed in both mated and unmated condition.  Enhanced strain relief eliminates cable overstressing, ensuring the integrity of cable sealing. 

The company’s canted spring technology not only enables snap-on/ breakaway coupling and decoupling but also 360 degree EMI shielding, an important factor with high-speed data signal rates. 

The design of the devices includes ‘blind mating’ for reliable and fast connection without the need for visual. 

Anti-reflective salt spray-resistant plating on the connector shells protects the vital cable interface and assists soldier concealment in marine environment manoeuvres. Human factor considerations include seamless ribbed over-moulding to give non-slip grip in damp conditions. 

The connectors can feature a patented draw back barrel design for cleaning and reconnection in seconds under field conditions. Rugged stainless steel construction provides durability, while an enhanced strain relief design eliminates cable overstressing.

Out in the field it is important that connectors are both small and light, to address this the company has developed its Trinity MKJ mini circular connectors. These provide similar electrical and mechanical performance to military standard environmental connectors but are up to 71 percent lighter and 52 percent smaller. They are available with threaded, bayonet and breakaway coupling for maximum functionality and flexibility.

The connectors use size 23 pin and socket contacts which accommodate 22 – 28 AWG, reducing contact spacing and giving the equivalent electrical performance of size 22 contacts.

Split tine contact design provides proven reliability in harsh environments and the connectors have been tested to withstand up to 20Gs vibration and up to 300Gs shock, in accordance with MIL-STD-1344. 

Of course the Mil-DTL 38999 circular connector remains ever-popular, but military and commercial aerospace manufacturers alike are under continual pressure to reduce the weight of aircraft and lightweight components can play a key role in achieving this. Consequently, many OEMs are migrating from aluminium to lightweight composite materials.

Using advanced materials and techniques the company’s new Mil-DTL-38999 Series III composite connector is on average 30 percent lighter than equivalent standard aluminium interconnects. Full advantage has been taken of recent improvements in the qualified ‘KJB’ design, which include part standardisation plus faster and easier assembly.  

The new composite connector includes Mil-DTL-38999/20 Wall Mount Receptacles and 38999/26 Straight Plugs in both Class J olive drab cadmium and Class M electroless nickel. Suitable applications include military and commercial aircraft, avionics systems and unmanned aerospace vehicles. 

To support local European customers and as part of its company commitment to the military and aerospace markets the company has also recently announced a major £500,000 investment at its Basingstoke UK plant.

The upgraded facility now offers streamlined manufacture and assembly, which delivers MIL-DTL-38999 connectors with market-competitive pricing and short lead times. 

The Basingstoke facility provides well managed levels of service for volume orders from OEM customers as well as value-add distributor partners operating in the fast-turnaround small volume sector. It is qualified to ISO9001-2008 and ISO 14001-2004, including the in-house plating line.

ITT Interconnect Systems