Magnetic connectors

The trend towards more mobile, lighter and more powerful medical devices presents designers with enormous challenges when developing innovative solutions. The devices must not only cover a wide range of functions and be appealing to the end customer in terms of design, 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 are implemented in the smallest of spaces, is particularly challenging. Printed circuit boards are increasingly being packed with powerful components and multi-layer, flexible printed circuit boards are being used. The connection technology is more complicated, as the integration of plug-in sockets is often difficult, especially in small devices, due to the required installation depth.

In addition, Connectors and Cables The device connection must be designed to suit the target group in order to function intuitively and safely. Older users in particular often find it difficult to operate small and delicate connection systems.

Magnetic connectors based on spring contacts can offer a solution.

Magnetic connectors impress with their flat design

In contrast to conventional plug-in systems, which require a certain insertion depth for optimal locking, magnetic connectors can be implemented with a very flat and level design. This means that the socket can be inserted almost flat into the Plastic housing An installation depth of just a few millimeters is sufficient for secure contact. This makes them particularly interesting for applications in the medical environment. This is because the elevations, gaps and crevices that come with conventional plug-in systems pose a high risk of contamination.

Sealing with elastomer materials or directly overmolding the magnetic connector with Plastic, ensure a system that can be cleaned and disinfected very easily. Protection classes up to IP68 for immersion disinfection are even possible. Another advantage of direct implementation or overmolded 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, shock- and vibration-resistant connection between the plug and the device. This makes the application very simple and convenient, especially in difficult or small installation situations. The polarity of the magnets means that incorrect connection can be ruled out, which ensures a high level of contact and functional reliability. In contrast to conventional plugs, the stress during contact and the associated wear of the socket is minimal with magnetic plugs.

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 requirements using different compositions and the limit values ​​of sensitive devices, especially in medical technology, can be sufficiently taken into account.

In an example from industry, a high magnetic force was required for a diagnostic cable in order to quickly contact the socket located under tables through strong self-guiding.

Spring contacts with up to 15A per pin

For power and data transmission spring contacts which impress with their small pitch and high tolerance compensation. They also allow for a high integration density and have a long service life. The standard value for rated currents is 1A per pin.

Depending on the material and internal structure of the spring contact pin, currents of up to 15A per pin are possible. This is a decisive advantage, especially for the charging time of batteries. Spring contacts are available in very small designs, with working heights from 1,2mm. The arrangement in the so-called right-angle design is also space-saving and allows contact to be made in a very small space. The coating of the spring contacts is usually done with gold, which has excellent electrical conductivity and offers high 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.

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.

Integration of assemblies in magnetic connectors

Just like with conventional plugs, other components such as status lights can be integrated into the magnetic connector. Sensitive electronic components, circuit boards or sensors are sealed using the hot melt process. Specifications for flexibility, impact resistance and shock absorption as well as UV protection and chemical resistance are taken into account by choosing different materials.

These electronic components are safely protected against corrosion and environmental influences, which makes them suitable for difficult applications with high humidity or strong temperature fluctuations. The user has many options when selecting the cable. The magnetic connectors can be assembled with almost any cable.

The great advantages of a magnetic release mechanism become apparent in practice. If the cable is pulled unintentionally, the device and the plug are not damaged and the risk of injury to the user is avoided.

In a current project, the integration of magnetic plugs into a sister emergency call system prevented the integrated wall socket from being torn out and the resulting damage to the device if the cable was pulled too hard. Other areas of application in the medical sector include charging cables with magnetic plugs for prostheses and wheelchairs.

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.