6 Novel Electrical Toy Risk Assessment Tools
Just how safe is that electronic toy?
09 June 2015
Exactly how safe is that electrical cable if your child decides to bite down on it? Will the button cell batteries of that toy come flying out if you child throws it against the wall? Intertek Product Intelligence was recently asked to develop some risk assessment fixtures and methods to address the safety issue for such scenarios. These novel fixtures assess risks from exposed current/voltage, manipulation of electrical cables, access to button cell batteries, and physical instability resulting in component damage.
The simplest path to electrical injury for a child is to simply touch a part of a toy that has live current accessible when the child and toy share a common ground. To address this, Intertek designed a set of voltage/current accessibility probes cast with electrically conductive silicon in various shapes such as a child's tongue and finger. The probes are equipped with built-in electrical resistance to mimic the worst-case resistance of skin. Any voltage or current detected is shown on an LCD display. Think of it as a high-tech version of the game Operation, where the point is to identify accessible current, instead of avoiding it.
Button cell batteries can cause horrible injuries to a child if ingested. A brand new, out-of-the-box toy should not have accessible button cell batteries, but what if a child has thrown it as hard as he/she can at a wall? If you have young children at home, you might agree it's a likely scenario. Compliance testing does address such hazards with a drop test, however, the fixture Intertek developed takes it a step further by propelling the toy at a steel plate at a speed determined by pediatric biomechanical studies.
A further set of 3 fixtures assess the robustness of electrical cords and cables including USB cables and charging cables. Each fixture focuses on a specific path to injury. The first fixture tests the cable when bitten, pulled, and twisted simultaneously. The second test focuses specifically on biting of cables, and the final test focuses on gnawing of cables. Each fixture uses cast bronze teeth molded from children's teeth. The fixtures bite, pull, and twist to forces determined by pediatric biomechanical studies.
The final fixture looks at the physical stability of the toy. A physically unstable toy can tip over and impact the ground, other objects, or even the child, potentially damaging the toy and allowing access to voltage/current or button cell batteries. A sensor detects when a sample is placed on the fixture test surface, then the angle of the test surface relative to horizontal increases until the sample falls off. The angle at which it falls is automatically detected and sent to an LCD display and computer.
It is important to stress that these are risk assessment tools, not compliance testing fixtures. If we see compliance testing as a ticket for entering the marketplace, risk assessment determines whether the product will last in the marketplace. Additionally, understanding the weaknesses of toys currently available can help the industry develop best practices to ensure safer toys in the future.
Ben Grigg, Research Scientist and Subject Matter Expert. Ben is a mechanical engineer and research scientist at the Oak Brook, IL location. His main focus is on the programming and design of custom electro-mechanical test fixtures and risk assessment.