Spring Applied Brake

What is a Spring Applied Brake?

A Spring Applied Brake is a type of brake that uses the powerful and reliable mechanical force of pre-compressed springs to engage (apply) the brake. It requires an external power source—such as hydraulic pressure, pneumatic pressure, or an electromagnetic field—to work against the springs and disengage (release) the brake.

This design is the foundation of virtually all modern industrial safety brakes and is often referred to as a “Fail-Safe Brake” or “Power-Off Brake.”

The Core Principle: Safety by Default

The operational philosophy of a spring applied brake is brilliantly simple and inherently safe. It operates in two states:

• Default State (Power Off): With no power applied, the springs are in their natural state of expansion, actively forcing the brake pads or shoes onto the disc or drum. The brake is ON by default.
• Energized State (Power On): When power is supplied, it creates a force greater than the spring force, compressing the springs and retracting the friction surfaces. The brake is OFF, allowing motion.

The Unmatched Advantage: Guaranteed Safety

The genius of this design is that any failure in the system—a power outage, a cut hydraulic line, a damaged cable—will eliminate the releasing force. When this happens, the springs instantly take over and engage the brake, bringing the machinery to a safe and secure stop. This makes the “safe state” the default state, rather than something that requires an active command.

Key Benefits:

• Inherently Fail-Safe: Provides automatic, reliable braking in any emergency or power loss scenario.
• Reliable Holding Force: The mechanical spring force is constant and highly reliable for static holding and parking applications.
• Fast Response Time: The mechanical action of the springs provides a near-instantaneous braking response when power is cut.
• Versatility: This principle is the backbone of emergency, parking, and in many cases, primary service brakes for critical machinery.

Applications:

The spring applied principle is the industry standard for any application where unintended movement could be catastrophic. You will find this technology in:

• Hoists and Cranes: To prevent loads from falling.
• Wind Turbines: For emergency rotor stops and secure parking.
• Elevators and Escalators: As the primary safety brake.
• Conveyor Belts: To hold the belt in place on an incline.
• Storm Brakes: To anchor large machinery against high winds.

The products and technical guides featured on this page are all centered around this critical safety technology. Explore these resources to learn how spring applied brakes form the core of modern industrial safety.