When do the compression springs push on the toggle links?

When do the compression springs push on the toggle links?

• A. When the air pressure is applied
• B. When the barrier is first energized
• C. When the air pressure is removed from the air cylinder
• D. When the pins shear

Answer: (C)

Compression springs provide the restoring force that moves the toggle links back to the safe position when the pneumatic actuation is released. While air pressure is applied, the cylinder holds the linkage in place and the spring is compressed, so it isn’t pushing on the links. When the air pressure is removed from the cylinder, the spring expands and pushes on the toggle links, driving them to the reset/safe position (and typically moving the barrier to its safe state). This is a fail-safe action: the system returns to a known safe state once control air is lost. The other options don’t describe this return action: applying air pressure holds the position, energizing the barrier isn’t the spring action, and pins shearing would be a fault, not normal operation.

Compression springs provide the restoring force that moves the toggle links back to the safe position when the pneumatic actuation is released. While air pressure is applied, the cylinder holds the linkage in place and the spring is compressed, so it isn’t pushing on the links. When the air pressure is removed from the cylinder, the spring expands and pushes on the toggle links, driving them to the reset/safe position (and typically moving the barrier to its safe state). This is a fail-safe action: the system returns to a known safe state once control air is lost. The other options don’t describe this return action: applying air pressure holds the position, energizing the barrier isn’t the spring action, and pins shearing would be a fault, not normal operation.