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Breakaway Connectors in Medical Devices

Breakway connectors used in surgery

Breakaway connectors can shortly disconnect to guard individuals and gear, but nonetheless present the identical pin and housing sturdiness as their mechanically secured counterparts.

By Steven Lassen, Product Purposes Engineer, and Julie Carlson, Advertising Communications, LEMO Breakaway connector

Breakaway connectors break the principles of system design that anticipate digital connectors to make a safe attachment — whether or not between a cable and a tool or two cables to one another. Sometimes, we would like connectors to be stronger than the load of the system or the bounds of the cable holding them collectively. In a surgical setting, for example, mechanically secured connectors can be sure that an by chance snagged cable doesn’t lose energy in the midst of a process.

Mechanically secured connectors sometimes make use of push-pull, lever-actuated, partial-turn, or different guide locking mechanisms which are designed to launch solely with particular consumer intervention initiated immediately on the connector interface and are in any other case engineered to carry tight — typically withstanding a pull pressure of dozens and even tons of of kilos.

LEMO breakaway connectors

Nevertheless, in lots of purposes there’s a want for connectors which are engineered to carry tight as much as a predetermined level after which, when that pressure is reached, easily and cleanly let go. Breakaway connectors, that are also called quick-release or quick-disconnect connectors, are sometimes employed in purposes together with aviation helmets and headsets that hooked up to cockpit consoles with cables, cellular medical monitoring gear hooked up to sufferers, and unmanned automobiles designed to launch payloads so as to forestall twine entanglement, snags, and pulls from hindering or harming the individuals and gear they’re hooked up to. 

breakaway connectors help protect patients

Find out how to Specify Breakaway Connectors

When specifying breakaway connectors, design engineers ought to first determine the variety of pins wanted with a purpose to calculate the specified quantity of pressure wanted to efficiently unmate the connector. Too little drive might result in overly frequent unmating, and an excessive amount of drive might contribute to bodily damage or gear injury. As a rule of thumb, the extra contact pins there are, the higher the inherent friction, which creates a direct minimal quantity of drive that the breakaway connector design should be sure you account for and overcome. In follow, most breakaway connectors are made to carry tight till subjected to forces between four and 15 kilos, though some can go a lot greater, and they’re virtually by no means specified for a precise determine (e.g., 5 kilos of pressure), however fairly for a slender vary (e.g., four–6 kilos of drive) to permit for small variances.

Breakaway Connector Applied sciences

As soon as the pressure vary is set upon, designers can choose from a variety of breakaway connector applied sciences able to satisfying each the pressure requirement and different software calls for. Latched breakaway connectors are one widespread answer since they make use of latch or tab options just like these employed in most mechanically secured connectors. Nevertheless, as an alternative of being designed to grip the within of the connector housing till purposefully launched via consumer intervention, the latches or tabs in breakaway connectors are designed — by way of cautious engineering and precision machined tolerances — to launch when the precise degree of drive is reached. Therefore, they’re also known as reduced-latch-force connectors.

One other group of breakaway connector applied sciences depends upon friction quite than mechanical means to create quick-release connections. Most of these breakaway connectors are typically known as latch-less options and are exactly engineered — typically utilizing one or a number of rubber or plastic O-rings or canted coil springs — to create the precise quantity of drag wanted to offer the specified degree of breakaway drive. The O-rings employed in breakaway connector designs are often wrapped round grooves machined into the connector housing with a excessive diploma of accuracy and tight tolerances to make sure that they obtain the specified drag and quick-release forces. Using O-rings also can present breakaway connectors with environmental sealing, water resistance, temperature resistance, and different helpful properties. For instance, Viton rubber is very immune to jet gasoline and different chemical compounds, EPDM elastomer is radiation resistant, and silicone could be immune to temperatures starting from -50°C to 200°C. So O-rings made of those and different specialised supplies are sometimes specified to be used in harsh-environment breakaway connector purposes.

breakaway connector technologies

O-ring, lanyard, and snap-ring breakaway connector applied sciences.

Canted coil spring breakaway connector applied sciences are additionally designed immediately into connector housings to offer the specified breakaway pressure and may present larger retention forces than O-rings even they nonetheless depend on friction, quite than latching mechanisms, to realize it. As well as, they too may be laid out in quite a few totally different supplies — sometimes metals comparable to brass, copper, or tungsten — to realize numerous properties, together with wonderful temperature resistance and EMI/RFI shielding.

One other breakaway connector know-how, the snap-ring design, works roughly like snap-on attire fasteners, with the connector clicking in, holding securely, and sliding again out over the connector solely when applicable pressure is exerted. Like canted coil spring variants, some of these breakaway connectors might be additionally engineered to realize larger breakaway forces.

Lanyard know-how is yet one more widespread breakaway connector answer. On this technique, a lanyard or ring-shaped wire is hooked up to the surface of a connector that should in any other case be launched on the connector juncture by the use of commonplace mechanical safety mechanisms, akin to push-pull or rotation options, and can override the guide unmating technique, enabling fast launch, if subjected to the required diploma of pull pressure. These lanyards can simply be marked with a tag or label for clear visibility and can be simply manipulated with gloves or different low dexterity means, corresponding to a robotic, which might be advantageous in some medical, industrial, and aviation purposes.

Matching Software Calls for to Connector Traits 

Along with figuring out the specified unmating pressure for a given breakaway connector answer, it’s additionally very important to look at the working surroundings through which it’ll be deployed, making an allowance for potential publicity to environmental circumstances — together with warmth, flame, chilly, sand, mud, salt water, rain, radiation, chemical compounds, vibration, ice, RFI/EMI, crushing forces, unusually excessive pulling forces, chopping forces, and different hazards — because the affect of such elements may be mitigated by correct element specification. Useful and aesthetic points referring to the appliance additionally loom giant within the connector choice course of, together with pin rely, wire measurement, color-coding, shell measurement, and weight.

Supplies

All kinds of supplies, together with numerous plastics and metallic alloys, can be utilized to fabricate breakaway connectors, and every delivers their very own set of execs and cons. For instance, plastic can present decrease weight and decrease value over time, however requires an funding in tooling. Aluminum is extra immune to put on than most plastics and is comparatively light-weight in comparison with different metals, however it’s much less corrosion resistant. Different metals, comparable to chrome steel or brass, are heavier however can supply greater levels of wear and tear resistance, sturdiness, and corrosion resistance.

Plating Supplies and Finishes 

In lots of instances, a connector’s base supplies could be plated to offer further properties or overcome limitations. For instance, a designer could possibly leverage the low weight and different useful properties of aluminum in a probably corrosive setting by specifying chrome plating to offer the required corrosion resistance and sturdiness, and even improved aesthetics. 

Plating supplies and different finishes might be specified for each practical and aesthetic causes. For instance, connectors is perhaps color-coded to match their mating companions to allow faster, simpler meeting in high-density electronics, for model differentiation, or to mix into the gadget design, which could be fascinating for connectors employed on the surface of digital methods, like medical screens. Colour-coding meant to help correct mating might seem as small dots or markings, whereas coloration meant for branding or glint discount, like a black matte end, is usually all-over.

One other consideration when specifying plating supplies and different finishes is sturdiness, which ought to match that of the connector itself. A coloured end or plating that degrades earlier than the top of a connector’s helpful lifetime can considerably detract from the advantages its meant to offer.

Shell Measurement 

Usually, the extra pins there are in a housing, the bigger the shell measurement must be. Equally, greater breakaway forces additionally are likely to require bigger shell sizes. Nevertheless, these generalizations are simply that and aren’t universally true. There may be huge variations in relative talents to pack extra pins or higher forces into smaller connectors based mostly on elements together with the dimensions of a given producer’s connector housings and mechanism designs, in addition to machining and engineering expertise.

Mating Cycles and Constant Efficiency 

As with all mechanical elements, the sides of the pins, housings, and different parts of breakaway connectors uncovered to friction can turn into blunted and worn over time, resulting in decrease minimal unmating drive necessities and elevated electrical resistance. Nevertheless, the purpose at which this begins to occur can range significantly, with greater high quality connectors designed to reliably carry out for a number of thousand cycles. Most connector producers supply both approximate tips or a assure relating to the variety of mating cycles their merchandise are designed to offer based mostly on elements together with materials and engineering high quality, in addition to testing and subject expertise.

Cable Interface Reinforcement 

A standard concern amongst product designers is the power of the termination level between the connector and the cable, and particularly so in purposes that make use of breakaway connectors and are thus more likely to be topic to excessive pull forces. Further reinforcement strategies, reminiscent of overmolding and potting, may help shield the cable terminations and be sure that the connector will unmate as anticipated slightly than rip the cable and wiring out of the connector when subjected to a sudden yank or excessive vibrations.

Element Value 

It’s also necessary to think about the whole value of possession for a given breakaway connector design fairly than simply the element value. For example, an element that may present a number of thousand extra mating cycles however is priced barely larger than an analogous half may be nicely well worth the funding of even a number of additional dollars, particularly since specifying low cost options over confirmed name-brand options may end up in downstream prices together with gear injury, guarantee points, security and legal responsibility points, gear downtime, and lack of enterprise. Some connectors additionally include value-added providers, reminiscent of product traceability and entry to technical specialists or restore technicians, which positively issue into complete value as properly.

The connection between the price of the gear and the relative value of the connector also needs to be thought-about. For instance, specifying a low-cost connector on a $500,000 moveable X-ray machine that’s anticipated to ship excessive accuracy and sturdiness is unlikely to end in long-term success.

The Worth of Customization for breakaway connectors

These are just some of the various specification issues and alternatives for breakaway connectors. Relying on the goal software, these connectors can be designed with shielding that resists electromagnetic radiation or radio interference, with breakaway capabilities from a number of totally different angles, and with touch-proof protections to mitigate the danger of electrical shock. Many breakaway connector producers additionally supply to work in partnership with design engineers to develop semi- to fully-custom options that take each conceivable component of a given software setting, desired connector efficiency, and general worth under consideration.

This text is excerpted from LEMO’s white paper, “Tips on how to Specify a Breakaway Connector.” See the article in its entirety on LEMO’s provider web page on Connector Provider.

Like this text? Take a look at our different Connector Fundamentals articles, our 2019 Article Archive, and our Medical Market Web page.

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