Magnetic connectors - design-oriented solution for medical devices

Magnetic connectors - design-oriented solution for medical devices

Also published in the Meditronic Journal 03/2022.
Article about magnetic connector as .pdf >>

The trend towards more mobile, lighter and more powerful medical devices presents designers with enormous challenges when developing innovative solutions. The devices not only have to cover a wide range of functions and be appealing in design for the end customer, but also meet the high requirements of the medical industry in terms of safety, reliability and hygiene. The development of small medical devices such as hearing aids, wearables or tracking systems, where powerful electronics have to be implemented in the smallest of spaces, is particularly challenging. Printed circuit boards are being fitted more and more densely with high-performance components or multi-layer, flexible printed circuit boards. It gets more complicated with the connection technology, because the integration of plug-in sockets is often difficult, especially with small devices, due to the required installation depth. In addition, connectors and cables for connecting devices must be designed for the target group in order to function intuitively and safely. Older users in particular often find it difficult to operate small and filigree connection systems.

Magnetic connectors based on spring contacts can offer a solution.

Integration of the magnetic socket in the housing
Integration of the magnetic socket in the housing

Magnetic connectors impress with their flat design

In contrast to conventional connector systems, which require a certain insertion depth for optimal locking, magnetic connectors can be implemented with a very flat and planar design. In this way, the socket can be integrated almost flat into the plastic housing. An installation depth of just a few millimeters is sufficient for reliable contacting. This makes them particularly interesting for applications in the medical field. Because it is precisely the elevations, gaps and crevices that conventional connector systems entail that harbor a high risk of contamination. Sealing with elastomer materials or the direct overmoulding of the magnetic plug with plastic ensure a system that can be cleaned and disinfected very well. Protection classes up to IP68 are even possible for immersion disinfection. Another advantage of direct implementation or overmoulded system solutions is that assembly times and costs can be significantly reduced.

Self-guiding connection through magnetic force

The implementation of magnets ensures a self-guiding, as well as shock and vibration resistant connection between connector and device. This makes it very easy and convenient to use, especially in difficult or small installation situations. Due to the polarity of the magnets, incorrect connection can be ruled out, which ensures high contact and functional reliability. In contrast to conventional plugs, the stress during contact and the associated wear on the socket with magnetic plugs is minimal. The risk of moisture and dirt penetrating the interior of the device is also virtually eliminated. In addition, the magnetic force can be adjusted to the respective requirement through different compositions and the limit values ​​of sensitive devices, especially in medical technology, can be sufficiently taken into account. In an example from the industry, a high magnetic force was desired for a diagnostic cable in order to quickly contact the socket located under tables through strong self-guidance.

customer-specific magnet solution for a round installation situation
Customized magnet solution for a round installation situation

Spring contacts with up to 15A per pin

Spring contacts are used for power and data transmission, which impress with their small pitch and high tolerance compensation. They also allow a high integration density and have a long service life. The default current rating is 1A per pin. Depending on the material and internal structure of the spring contact probe, currents of up to 15A per pin are also possible. This is a decisive advantage, especially for the charging time of batteries. There are spring contacts in very small designs, with working heights from 1,2mm. The arrangement in the so-called right-angle design also saves space and allows contacting in a very small space. The spring contacts are coated as standard with gold, which has excellent electrical conductivity and offers a high level of protection against corrosion and oxidation.

Coating against electrolytic or galvanic corrosion

However, there are already further developments that are particularly interesting for wearables. For example, the Super AP coating is extremely resistant to electrolytic/galvanic corrosion while maintaining very low resistivity. Compared to a gold coating, the Super AP coating is twice as resistant to salt water, five times more resistant to perspiration and 30 times more resistant to electrolysis. Corrosion of the electrical contacts caused by sweat or moisture is effectively minimized.

Round magnetic connectors allow 360° rotation
Round magnetic connectors allow 360° rotation

Individual design for magnetic connectors

There are almost no limits to the shape and color of a magnetic plug. Individual color accents and design requirements can be easily implemented using the appropriate tools. Some forms also require advantageous features. For example, round plugs with an outer magnetic ring allow 360° rotations with constant contact. When used in a handset, the cable cannot be twisted and cable breaks avoided.

Diagnostic cable in the hotmelt process to protect electronic components
Diagnostic cable in the hotmelt process to protect electronic components

Integration of assemblies in magnetic connectors

Just like with conventional connectors, other components such as status lights can also be integrated into the magnetic connector. Sensitive electronic components, circuit boards or sensors are sealed using the hotmelt process. Specifications related to flexibility, impact resistance and shock absorption, as well as UV protection and chemical resistance can be accommodated by different materials. The electronic components are protected against corrosion and environmental influences and are therefore also suitable for difficult applications with high humidity or strong temperature fluctuations. When selecting the cables, the user can draw from plenty. The magnetic connectors can be assembled with almost any cable.
In practice, the great advantages of a magnetic release mechanism are evident. In this way, the device and the plug are not damaged if the cable is pulled unintentionally, and ultimately the risk of injury to the user is avoided.

In a current project, the integration of magnetic plugs into a nurse's emergency call system prevented the integrated wall socket from being torn out and the associated damage to the device caused by tugging on the cable too hard. Other areas of application in the medical field include charging cables with magnetic plugs for prostheses and wheelchairs.

Magnetic adapter for re-design - custom development
Magnetic adapter for re-design - custom development

The wheel does not always have to be reinvented to equip a product with magnetic plugs. With the help of customer-specifically developed magnetic adapters, existing operating systems can also be easily converted to this convenient connection system. Proven input devices are given a design-oriented relaunch. In addition, some standard solutions enable a quick conversion of USB connections.

Creative solutions for developers

In summary, it can be said that magnetic connectors offer developers creative solutions and open up new design approaches - not only in medical technology. The extent to which a customer-specific solution is worthwhile, also taking into account economic aspects, always depends on the individual case. Perceived as a convenient and innovative connection solution, it definitely offers the devices added value in terms of design and handling, along with a differentiation from competitive products.

Inquiry about magnetic connectors

We realize magnetic connectors including cable assembly for all sectors and industries. We are happy to take over the design and development for your application.
Especially in the field of medical technology and e-mobility, we have already been able to implement a large number of magnetic connector solutions for our customers.
We look forward to your inquiry, gladly by email: or by telephone: 02154 81250.

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