Techdrives is now supplying Intorq energise-t-release calliper brakes for safety-critical applications with large masses or falling loads. Effectively these calliper designs are developed from disc brakes and their kidney shape enables compact assemblies to be created with disc diameters from 150-850mm. Interruption of the DC supply voltage results in the full clamping force being applied to the brake disc. Depending on dimensions and the number of callipers, the brake torque can be from 100 to 10,000Nm.
The main calliper brake model, the BFK466, is robustly constructed for safety-critical applications. Multiple helical springs apply force to a floating armature plate that clamps onto a brake disc, which would normally be part of the machine. High-stability friction material between the brake and the rotating disc increases the resulting torque. To release the brake a DC voltage is applied to typically four electromagnetic coils inside the brake, which pull back the armature plate to a released position with no residual torque. Intorq 'cold brake' technology applies over-excitation of the coils for the fast release and then a lower holding current. This reduces energy consumption and heat generation, and also speeds the brake re-engagement when the DC supply is interrupted.
As well as the reliable design concept of multiple springs and coils, Intorq gives a high priority to long service life and safety. B10d lifetime data is available for evaluating the performance level of machine braking systems; for the BFK466 it is 12million hours. The concept of a 'redundant calliper' is normally used in safety-critical applications so that if one calliper fails there is another available to stop the load. This is most effective where there are several callipers. For example, a brake with five active callipers would only require one more to be added for redundant safety – on the basis that only one calliper would ever fail at one time. Costs are therefore minimised and the redundant calliper only adds an extra 20 per cent torque, which avoids over-braking lighter loads. Intorq also fits microswitch detection of brake actuation so a fault is identified immediately.
Intorq spring-applied calliper brakes are described on the Techdrives website. The BFK463, which is a new model, suits smaller drives with typical braking torques of 100Nm. There is an intermediate model BFK456 and a larger BFK466 that can deliver around 1500Nm per calliper. These caliper brakes are aimed at lifts and hoists, particularly where the motor is of the direct-drive type without gearbox. They also suit general braking duties for high loads - for example, where safety integrity requires braking at the low speed output rather than through a gearbox.
Follow the link for more information about Intorq calliper brakes for safety-critical applications.