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 MoreQ & A: Category 2 and Testing Intervals

During the Free Safety Talks with Schmersal Canada and Franklin Empire, we had a “hot question” regarding Category 2 architecture and the testing interval requirement. Category 2 in [1, 6.2.5] does not mention a minimum testing rate, but [1, 4.5.4], “Simplified procedure for estimating the quantifiable aspects of PL,” adds a requirement for test rate…
Read MoreFive reasons you should attend our Free Safety Talks

Reason #1 – Free Safety Talks You can’t argue with Free Stuff! Last week we partnered with Schmersal Canada and Franklin Empire to put on three days of Free Safety Talks. We had full houses in all three locations, Windsor, London and Cambridge, with nearly 60 people participating. We had two great presenters who helped…
Read MoreCSA Z432 Safeguarding of Machinery – 3rd Edition
If you build machinery for the Canadian market or modify equipment in Canadian workplaces, you will be familiar with CSA Z432, Safeguarding of Machinery. This standard has been around since 1992, with the last major revision published in 2004. CSA has reconvened the Technical Committee responsible for this important standard to revise the document to…
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…
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