EOX Elevator Safety Components
The safety gear system in an elevator is the last line of defense when all else goes wrong.
That means that these mechanical components have to operate consistently and effectively even when there is no power to the system. This project married my love for calculations and for design work, as well as the responsibility that my designs could directly help save lives should the time come.
The Safety Gear System consists of three main components: an overspeed governor, which a flywheel that locks up if the elevator moves too fast; safety blocks made up of wedges that gradually slow the car during such an event; and a tensioning weight or device that keeps a rope linking the governor and block taut. When the overspeed governor locks up, the block’s wedges clamp down onto the vertical rails that guide the elevator’s motion.
The challenge here is to slow the car down just enough to prevent harm to the people inside the car, but quickly enough to prevent the car from hitting the elevator buffers at the bottom of the elevator shaft. While ASME A17 Elevator Code and building inspector tests dictate hard requirements on the limits of when the safety gear should trip, the nuances of the forces required to trip the mechanism are still left to the design engineer.
Example of a Safety Gear block (above) that would be on one side of the elevator car. Another block similar to this would be on the other side of the elevator car.
Example of Overspeed Governor (right) that would be at the top of the elevator shaft, and locks up when the car moves too fast.
I was fortunate to join TK Elevator under the tutelage of two senior engineers, one of them a Chief Engineer that helped design for the current One WTC elevator. When they moved to other projects, I helped shepherd the launch of the safety gear and overspeed governor in the first EOX elevator. During this development, I also helped deep dive into elevator code compliance and aided in getting future versions of the code improved. Since then, I have worked hard on developing solutions for future releases on the EOX elevator platform.