Everyday Poka-Yoke: Door Knob Safety

Poka-Yoke, or Error Proofing, Mistake Proofing is a helpful tool in Lean Thinking.  But, like any tool, there’s a method to how to implement the principle of “prevent defects from happing”.  And, the method and principle is important to know, otherwise the situation becomes one of learning how to use a hammer and then looking at everything as a nail.

What Are We Solving For?

Here’s one example:

• Defect: My child opens doors he is not supposed to open, endangering his safety.
• Root Cause: Nothing prevents my child from opening the door
• Countermeasure: Prevent the Door from Opening

PDCA

The problem solving involved in implementing the principle of Poka-Yoke still follows the Plan-Do-Check-Act (adjust) cycle, as I show above.  The countermeasure?

Yeah, prevent the door knob from being opened.  This simple Poka-Yoke device will prevent your children from opening doors and potential safety hazards.  Simple, right?  But, the important lesson is the thinking that went into the development of this device – a device that became a huge market for this company (Safety First, Safety 1st).