When do the compression springs push on the toggle links?

The correct answer indicates that compression springs push on the toggle links when air pressure is removed from the air cylinder. This mechanism works typically in systems where the springs are engaged to restore or reset the position of the toggle links once the compressive force (in this case, the air pressure) is no longer present.

In such systems, the springs are designed to apply force to the toggle links when the operating pressure is removed. This ensures that the links return to a home position or engage in another function that requires their movement. As the air pressure releases, the springs exert their stored energy, resulting in the to-and-fro motion necessary for the operation of the toggle mechanism.

In contrast, air pressure being applied to or removed from the cylinder affects the system's state in other ways but does not lead to the activation of the springs in relation to the toggle links. For example, when air pressure is applied, it typically serves to engage or move components rather than allow springs to take action in pushing against the toggle links.