Special tooth brakes from Mönninghoff, available from Techdrives, are used to fix a three-axis medical device for positioning a surgical probe. The brakes are part of an assembly that can be freely positioned by hand when power is off. Engaging the brakes by applying a safe 24V DC supply fixes the arms accurately in the chosen position. A key part of the decision to use tooth brake technology was the ability to produce high torques with compact dimensions, 200Nm with a body diameter 95mm in this case.
Mönninghoff electromagnetic tooth brakes normally have around 280 standard teeth. In this holding application the number was increased to 480, giving a maximum error on the engagement position of +/- 0.375 degrees. This is acceptable for the position of the probe. In the event of a power supply failure during use the brakes disengage allowing safe withdrawal. However, these tooth brakes can also be supplied as spring-applied, energise to release versions that hold position in the event of power failure.
Electromagnetic tooth brakes are also suitable to fix position with scanners, antennas, barriers and gates where their slip free and small size properties are valuable. Energise to engage brakes are available from 20 to 2200Nm and spring applied models from 10 to 1600Nm. In the UK Mönninghoff tooth clutches and brakes are available through Techdrives, with information on the website www.techdrives.co.uk and full technical support available.