Category: Hierarchy of Controls

Emergency Stop Pull-Cords

This entry is part 14 of 14 in the series Emer­gency Stop

When it comes to emer­gency stop devices there is no doubt that the red mush­room-head push but­ton is the most com­mon – they seem to be every­where. The second most com­mon emer­gency stop device is the pull-cord, and like the light-cur­tain in safe­guard­ing, the pull-cord is prob­ably the most mis­ap­plied emer­gency stop device. Con­tin­ue read­ing “Emer­gency Stop Pull-Cords”

Trapped Key Interlocking

This entry is part 3 of 7 in the series Guards and Guard­ing

Many machine design­ers think of inter­locks as exclus­ively elec­tric­al devices; a switch is attached to a mov­able mech­an­ic­al guard, and the switch is con­nec­ted to the con­trol sys­tem. Trapped Key Inter­lock­ing is a way to inter­lock guards that is equally effect­ive, and often more appro­pri­ate in dif­fi­cult envir­on­ment­al con­di­tions. Con­tin­ue read­ing “Trapped Key Inter­lock­ing”

How to Apply a Safety Edge to a Machine Guard – Part 3: Stopping Performance

This entry is part 7 of 7 in the series Guards and Guard­ing

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 need to con­sider when apply­ing these devices. Con­tin­ue read­ing “How to Apply a Safety Edge to a Machine Guard – Part 3: Stop­ping Per­form­ance”