The electromagnetic spring applied, power off brake (sometimes known as a safety brake or fail-safe brake) is designed so that when the electrical power supply is off, the brake comes on (power-off brake engagement). The spring applied brake can be designed to be used as a holding brake (parking), or dynamically where an emergency stop functionality is required (E-stop).
The spring applied brake is strong and reliable, generally incorporating multiple internal compression springs. The springs provide an added safety feature, where the brake would still function should one spring fail prematurely. On ‘power off’, as the coil’s magnetic field collapses, the springs force an axially moving armature plate forwards to engage and Read More...lock the rotating friction disc.
The electromagnetic spring applied brake is ideal for integration into servo motors and can be mounted externally or integrated into the motor housing.
The electromagnetic spring applied brake is one of our most versatile brakes with a torque range of 0.05Nm to 300Nm. The non-asbestos lining construction of the rotating friction element is available in three different types (depending upon the application and torque required):
1. Mainly static applications – single piece friction disc assembly, with drive interface direct into friction discs
2. Mainly semi-dynamic applications – two bonded aluminium friction discs for increased shear strength and shock loading
3. Higher strength applications – steel carriers of hardened steel with double bonded friction discs, for more demanding and dynamic applications
Depending on the acceptable level of backlash, some spring applied power off brakes have the option to have either a spline or hexagonal drive ensuring minimal circumferential backlash.
During its manufacture, the airgap is pre-set on the spring applied brake for ease of installation. Where longer term `in-situ` airgap resetting is required, this can be achieved with adjustable spacers, without needing to totally remove the brake from the motor.
The spring applied brake has a hand release option to manually override the brake without power. This is suited to applications such as fork lift truck machinery, wheelchairs and actuation and valve systems.
The spring applied power off brake can be face mounted or flange mounted in any orientation and due to its reliability, is suited to safety critical applications in the material handling, military and medical sectors. They are often used in automation and robotic applications as well as packaging machines, storage systems and in renewable energy.
As the spring applied brake does not contain permanent magnetic material, it is more tolerant of high temperatures than the permanent magnet brake. Its temperature range is between – 15°C to 120°C. An ‘IP’ water (or “Ingress Protection”) resistant design may also be available for installation into moist environments.
Rubber dust sealing rings may be incorporated to prevent ingress of foreign matter. Drive hubs can be supplied with brakes, complete with bore and keyways to suit the specific application.
This is a SG Transmission type 56 spring applied, power-off brake, download the datasheet.
Alternatively, click here to view the type 52, power-on brake.
- Power off brake engagement/electrically released
- High braking torque
- High operating speeds (dependent on size)
- Precision holding
- Low inertias
- Horizontal and vertical mounting
- Toothed hub/friction disc connection
- Water resistant versions available
- Optional voltages