Stopping Safely with ServoStop

Sometimes an assembly line has to be stopped immediately to ensure the safety of employees and protect manufacturing machinery. Stober Drives, Inc. of Maysville, Kentucky, has introduced an emergency braking system called ServoStop, which provides safe braking at emergency stops and during power outages. "It's an attention grabber," said Adam Mellenkamp, ServoStop product manager for Stober. "Everyone we show it to may not be able to use it right now, but can think of a situation where they could have used it in the past. It was originally designed for a safety application where you need redundant braking. No one else really has it on the market, and it has a lot of innovative features."

ServoStop can brake dynamically up to 1,000 cycles. It has electronic release monitoring and sensors, manual brake release, and electrical wear monitoring options. The emergency braking system can be mounted on almost all common servomotors, giving it endless applications in factories universally, and is an integral part of Stober's ServoFit gear reducers. It has a plug-in coupler for simple motor removal, and no matter what position the braked axis is in, prevents gravity-affected axes from sinking or crashing.

"If you need a brake, this is the 'easy button' to get it," said Mellenkamp. "You won't need another supplier to adapt it. The ServoStop is also extremely compact due to the integration into the gear unit." Providing safe braking can be difficult as well as dangerous, especially when machinery incorporates vertical axes which is common in material handling for robotics or machine tools industries. Dangerous situations can be caused by a cut-off of drive power due to a problem in the machine controller, power failure or brake failure in the motor, said Mellenkamp. "While other brakes can allow sliding, ServoStop can brake at full speed, prevent accidental sliding or falling of vertical axes with gravity load, and provide reliable braking during emergencies and power failures."

Advantages of the ServoStop coupling are that it allows for simple removal of the motor regardless of the position of the brake axis, even with load; it is backlash-free and smooth-running; it offers frictional shaft to hub for high torque; and provides a compact design for low inertia.