Small Solutions, Big Advances

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Designers of military, law enforcement, homeland security and border protection equipment have a seemingly impossible job. In addition to delivering rock-solid products for today’s applications, they are challenged to predict the future - to look beyond existing platforms and performance standards and produce gear that is lighter, faster and easier to deploy, with fewer components and more flexibility. In their search for solutions to this challenge, a growing number have discovered the simple, versatile Bal Spring® canted coil spring.

Pioneered more than 50 years ago by engineer and entrepreneur Peter J. Balsells, the Bal Spring consists of wire (in various materials, sizes and surface treatments) that has been precision coiled and resistance or laser welded to a specific diameter. In addition to fastening or “latching,” the spring can be designed to permanently lock two pieces together, or to perform a holding function through the application of a specific amount of friction between two components. It also performs electromagnetic interference (EMI) shielding and grounding functions, and can serve as an electrical contact between two pieces.

While engineers have relied on the canted coil spring to solve mechanical fastening and electrical conducting problems in the past, the increasing complexity of designs, coupled with escalating pressures to “do more with less,” has led to more widespread adoption in defense and security equipment. The spring’s multi-function capabilities and compact footprint have earned it a critical role in designs for unmanned aerial vehicles, ground robotics, man-worn field systems and many other platforms.

In Unmanned Systems

As UAVs are deployed for a broader scope of missions, the drive has been to make them smaller, more light-weight and more man-portable. One of the most common challenges in compact UAVs is the need to quickly assemble or remove and replace modular parts (i.e., wings, tails, EO/IR pods, etc.) during normal operation or in the event of a hard landing/crash – without the use of hand tools. Additionally, weight is a concern for these smaller vehicles, so the need for multi-function components is critical.

The canted coil spring, combined with the appropriate groove dimensions, has helped engineers address these problems. With the ability to customize the insertion and removal forces of the spring latching technology, a user can easily assemble or re-assemble the wings, tail-section, EO/IR pod or other pieces without tools. If the aircraft lands hard, the wings can be engineered to “pop off” at the desired removal force and allow for quick re-attachment. And if electrical, grounding or electro-magnetic interference (EMI) capabilities are required, the springs answer these needs, as well.

Similarly, unmanned ground systems requiring the capability to quickly connect and disconnect modular hardware (i.e., manipulator arms, mechanical fingers, sampling tools, etc.) have benefited from canted coil spring technology. The custom design of a canted coil spring and groove configuration has allowed for quick and easy assembly of modular parts, and the spring’s ability to ground/shield has proven to effectively protect systems from the harmful effects of EMI emitted by other electronics.

In Ground Personnel Equipment

In radios, GPS units, laser range finders, laser pointers, flashlights, computers and other electronic devices used by military or law enforcement ground personnel, maintenance of a rugged, reliable electrical connection is a must. In addition, weight is a consideration; for personnel carrying loads over long distances, every ounce counts. Other requirements often include ease of installation and removal (blind mating), temperature resistance and excellent EMI shielding properties.

The unique mechanical and electrical properties of the Bal Spring canted coil spring also have made it an ideal solution for these types of applications. The spring offers customizable connect/disconnect forces, 360° shielding capabilities, and reliable performance at high temperatures in the harshest environments.

The Bal Spring may not be the answer to all defense equipment design challenges. In fact, there may be instances in which the variability of more traditional fastening methods will be acceptable for an application. But for engineers tasked with creating tomorrow’s technology, this simple, multi-purpose component is an alternative that provides the right mix of performance characteristics.



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