Connectors Offer Durability, Superior Functionality and Practical Application for the Modern Military
By David Impett, Product Manager at ITT Interconnect Solutions
Military and defense applications require component solutions that are highly reliable, as the consequences for in-field failure can be catastrophic. Material selection is critical for applications that experience shock, vibration, high pressure and/or extreme temperatures.
Harsh environment and mission-critical systems require connector solutions with superior performance, reliability and durability. Technological trends in military applications also call for highly dependable materials, reduced size and weight and greater functionality. Deployed in a variety of modern military and “future soldier” applications, such as sophisticated command, control, communication, computer, and intelligence (C41) systems, spring/probe connectors offer these design considerations. Rugged spring/probe interconnects offer a high-density signal packaging approach within a confined space, enabling soldiers to become more mobile and their advanced equipment to become more portable.
Most interconnect devices currently available do not offer design engineers a solution that increases signal functionality while meeting confined size constraints, high-temperature requirements and sealing ratings necessary for today’s military applications. The Nemesis Space Saver Series features two unique design elements – the breakaway Pogo Pin/Pad contact that delivers enhanced contact durability; and the canted spring/probe technology, which provides not only ‘snap-on’ and ‘rip-away’ coupling action to prevent a soldier’s life from being endangered if a cable is snagged, but also 360˚ EMI shielding. Combined, these designs deliver a miniature connector solution with superior performance, reliability and durability. The Nemesis Water Tight, High Mating and Super Clean Series is 50% lighter, 60% smaller and fully sealed compared to conventional connectors.
With its unique size 22 termination system, the interconnect successfully passed comprehensive design verification testing (DVT), including meeting stringent specifications for mating repeatability, temperature cycling, vibration, mechanical shock, humidity and mating durability. This connector also offers high density of up to 50 channels per square inch and removable sleeve inserts that allow direct end-face access for termination cleaning and inspection.
Size and Weight
While materials such as stainless steel are highly reliable, they add to a connector’s weight. Components for soldier-carried systems are always a compromise between weight and performance. Applications need to be robust, yet as lightweight and small as possible. These are conflicting demands – robustness often requires the use of stainless steel, as it is extremely durable and allows for a significant number of mating and un-mating cycles; yet it is heavier than alternate materials. An overall weight saving was achieved with Nemesis by decreasing the connector’s size.
In terms of size, the spring/probe contact spacing can be as small as 0.635mm, providing high signal density in minimal space, whereas other designs feature size 23 pin-and-socket contacts that have the equivalent electrical performance of size 22 contacts, reducing contact spacing to as little as 0.193mm. In some designs, the use of size 23 contacts for the interconnection of the cable also allows for the use of less stainless steel, thus decreasing both cost and weight.
The spring/probe contact spacing is reduced down to 0.635mm, thus providing high-signal density in the minimum of space. The lightweight, small form-factor design offers significant space savings for electronic equipment, and can reduce the size of a device by 60%. While many connectors are inherently small, especially given the amount of power they are capable of delivering, system designers continually seek smaller designs.
Durability and Rugged Performance
Most plastic connectors, even ones with metalized plating, are unable to meet the military reliability and performance standards. Connector shells made of stainless steel material meet stringent requirements for corrosion resistance under MIL-Spec “P” grade standards, while at the same time meeting JEDEC standards for RoHS compliance. Other connector designs are constructed with high temperature LCP dielectric materials, allowing them to be employed in applications with temperatures as high as 200°C, such as military vehicles as well as space and avionics use. The rugged stainless steel construction provides durability, while an enhanced strain relief design eliminates cable overstressing. Anti-reflective salt spray-resistant plating on the connector shells protect the vital cable interface and assist soldier camouflage in marine environment maneuvers, while the seamless ribbed overmolding provides a non-slip grip in damp conditions.
Receptacles that utilize spring probe contact system and touch pads allow for ease of cleaning in the field where dirt, moisture, mud, sand and other contaminants may be present. The individual touch pad contacts incorporate no crevices for contaminants to accumulate – a desirable feature in harsh environment field conditions – while eliminating the need for dust caps. This technology is complemented by Nemesis Super Clean patented draw back barrel cleaning technology, which allows the user to clean the plug connector and be operational again in only a few seconds.
Offering a simple mating mechanism enables users to mate and un-mate the connector system quickly as the need arises. The connector’s ‘blind mating’ design provides reliable and fast connection without the need to see the mechanical keying. Multiple keyway options are incorporated into the interconnect family to prevent any possibility of mis-mating. The interconnect also provides plug polarization color-coding to allow users to easily identify the correct mating connector, which is an important feature for applications with duplicated connectors. The typical pull force is 5lbs to 8lbs, but may be adjusted based on specific connector design considerations. The Pogo Pin/Pad connector technology increases the number of mating cycles, guaranteeing more than 10,000 cycles.
The internal clip mechanism also maintains constant connection with the contact itself, reducing electrical resistance and accommodating misalignment issues.
The pogo pin/pad connectors are fully sealed in the unmated state (watertight to 20m) and weigh less than 25g, which is critical for on-soldier applications. The spring probe system allows the connector receptacle to house individual touch pad contact areas. This design allows for an effective electrical engagement point of contact. Further, the spring probe contact system and touch pads allow for ease of cleaning in the field where dirt, moisture, mud, sand, and other contaminants may be present. Standard termination options include PCB tails, solder cups, and pin contacts.
Today’s military electronic system design engineers are required to develop products that increase functionality and withstand extreme environments. Even more demanding is the need for continuously evolving smaller and lighter electronic systems where space and weight are at a true premium. Not only must designers ensure that their system modules perform in demanding elements, they must ensure that the interconnect link for their systems survive and maintain signal integrity. Electronic interconnects designed and integrated into electronic equipment for harsh conditions must be able to withstand severe shock, vibration, and thermal dynamics.
ITT Interconnect Solutions
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