Many machine designers think interlocks are exclusively electrical devices; a movable mechanical guard is fitted with an electrical interlocking device, and the interlocking device is connected to the control system. Trapped Key Interlocking is an equally effective way to interlock guards that is often more appropriate in severe environmental conditions or where the guard is…
Read MoreHow to Apply a Safety Edge to a Machine Guard – Part 3: Stopping Performance
In Part 2 of this article, I looked at the pressure-sensitive devices (safety edges) themselves. This part explores the stopping performance requirements that engineers and technologists must consider when applying these devices.
Read MoreHow to Apply a Safety Edge to a Machine Guard – Part 2: Design Considerations
In Part 1 of this article, I looked at the pressure-sensitive devices (safety edges) themselves. This part explores the design requirements that engineers and technologists must consider when applying these devices.
Read MoreHow to Apply a Safety Edge to a Machine Guard – Part 1: Pressure-sensitive devices
Safety Edges are often forgotten as safeguarding devices. Most machinery engineers and designers are familiar with interlocking devices and light curtains. Once we step away from the familiar, our understanding of applying safeguarding devices like a safety edge becomes a bit foggy.
Read MorePresence Sensing Devices – Reaching over sensing fields
I recently heard about an application question about a light curtain with a small gap at the top of the sensing field, between the last beam in the field and the surrounding structure of the machine. Some concern was raised about the gap and whether or not additional guarding might be needed to close the…
Read MoreCanada Adopts ISO 13857 – Safety Distances
Safety Distances As part of the work on the 3rd Edition of CSA Z432, Canada has decided to adopt ISO 13857 as CAN/CSA-ISO 13857. The standard was adopted in 2015 without technical deviations. Why ISO 13857? CSA Z432 has long had portions of the information in ISO 13857 in its annexes – Annex C has…
Read MoreInterlocking Devices: The Good, The Bad and the Ugly
Note: A shorter version of this article was published in the May 2012 edition of Manufacturing Automation Magazine. When designing safeguarding systems for machines, one of the basic building blocks is the movable guard. Movable guards can be doors, panels, gates or other physical barriers that can be opened without using tools. Each of these…
Read More