Magnetic Interconnect System
Client : UK Manufacturer of Fuel Monitoring Systems
Industry : Industrial
Commission : The outline was to provide a cable and connection system for a Fuel Monitoring System that would link a fleet vehicle to the monitoring unit when back at base/depot for re-fuelling. The system would then allow transfer of information between the vehicle and the monitor unit.
The key challenges to address when developing the solution were:
- High number of mating cycles (up to several hundred cycles per day)
- Connector to accommodate a PCB and reader device
- Cable mounted connector to be ‘drop proof’ to protect internal electronics
- Connection to be ‘fail safe’ should vehicle drive away whilst still connected
- System to be protected for heavy automotive environment
- Cable to extend up to 6m in length
Scope of Works : The main challenge was to identify a connection method that would pull apart safely should the vehicle accidently drive away whilst still connected. Traditional pull-break connector systems were reviewed that use either coupling ring mechanisms or friction fit but neither of these solutions would survive the extremely high mating cycle requirement. Magnetic connection methods were therefore considered and trialled. The magnetic force however had to be just right - strong enough to hold the connection securely when static but able to pull apart should the vehicle accidently drive away. Variation in the angle of pull also had to be considered.
Results : The connection cable is built using an extending coiled cable with a Polyurethane outer jacket to survive the outside environment and chemical exposure. The PCB reader device is then attached to the end before being overmoulded using a special epoxy resin to provide the environmental sealing and the rugged drop-proof protection. The moulding is shaped to form a circular connector which houses six high power magnets in the mating surface. The mating vehicle mounted connector is also moulded and incorporates a magnetic stainless steel disc to which the magnets connect. The positioning of the magnets which are controlled by an assembly jig is critical in order to provide a strong connection but prevent interference with the electronic data transmission. A domed shape keying feature in the front face allows safe disconnect when pulled from all angles.
Further Notes : The system is now in full production and is currently in use by a number of vehicle fleet operators around the UK. Phoenix Dynamics 3D printing capabilities played a key part in the product development allowing scale replicas of early ideas to be demonstrated. Replicas of the final design where also supplied to the customer for marketing purposes at trade shows.
