Posted By Robert. Quite a mouthful John. I think I know what you mean, that the start operation is shrouded by the red flap to prevent accidental start-up The actuators irrespective of function should have "life span of actuations". I remember that Telemechanique or other manufacturer provided that info. based on that you could plan in a maintenance schedule. The e-stop could also double up as the functional stop insomuch that it isolates, through safety control relays / contactor, to a fail to safe situation. The stop may also initiate an elecro-brake system on each actuation on some rotating machinery. If youre having 50 stops a day then you are also having 50 starts except that the actuator makes contact momentarily when pushed. There is no reason why you shouldn't be able to put in a remote e-stop to satisfy the risk assessment should the operator for some reason be unable to actuate an e-stop. But also consider that other persons may not be near enough to use it. By the way is the red stop flap at knee height?

Posted By Peter Still John, I'm employed by a market leader in supplying e-stop buttons, so I'd like to tell you to fit extra buttons, but that simply can't be justified in many cases. As far as new machinery is concerned, EN 60204-1 will tell you to fit e-stops at all locations where they might need to be operated. However the standards for individual machine types (C standards), that in most cases will have been used to perform an EC Type Assessment for the machines, often allow the use of a combined functional stop and e-stop button. From a pushbutton manufacturer's point of view this is quite acceptable when a good-quality pushbutton is used. 50 stops per day is not a problem for any of the major manufacturers' products. What is more important is that you understand the tasks to be performed at of each of the machines, and the circumstances when the e-stop might be used. For example if an operator is using one hand to hold a workpiece on a pillar drill, and the other to feed the drill down, he will need to be able to reach an e-stop with his knee or foot but it is unlikely that a bystander would be able to recognise a risk and operate the e-stop. In the case of more complex machinery it is more common for additional e-stops to be needed to deal with problems that are not visible to the operator. However it is preferable to redesign the task to reduce the likelihood of needing to operate an e-stop; in my pillar drill example, the use of an appropriate fixture (e.g. a drill vice) can free up the opertor's hand to operate the stop control, as well as redicuing the likelihood of the workpiece catching on the drill and rotating. Remember that an e-stop is only there to stop dangerous mechanical movements. It is not for use to keep a machine stopped during e.g. tool changing, and it does not provide isolation so is not to be used for electrical work. There should be a supply disconnecting device that is capable of being locked in the off position and is accessible.

Posted By Peter Still Tabs, I can't argue with what you're saying. As I mentioned, EN 60204-1 would have you install e-stops at all locations where a risk assessment shows them to be necessary, and if you feel they are necessary at multiple locations on each machinethen you can of course install them. Please bear in mind though that they are not a substitute for adequate safeguarding. As the new Machinery Directive puts it: "Emergency stop devices must be a back-up to other safeguarding measures and not a substitute for them." As for normal stops failing and the e-stops working, in most cases they are the same kind of device, wired into the same circuit. In some machines the e-stop is monitored to detect electrical failures, but if that's considered necessary on an e-stop it should also be done on the normal stop.

Posted By Peter Still John, brakes fitted to bandsaws need careful setting to avoid stopping too quickly and breaking the blade. However all machines must by law have emergency stops fitted, with only 2 very specific exceptions allowed in the Supply of machinery(safety) regulations. Peter

Posted By Peter Still John, Ideally you should check with the manufacturer of the bandsaws that the machine and its motor can withstand the likely frequency of operation of the brake - presumably you are considering electrical braking, which can increase the motor's temperature if used too frequently. The manufacturer should also be able to confirm if stopping in 10 seconds is acceptable. Did you mean there is 5cm of blade exposed when the material being cut is present? That is, is there 5cm exposed under the guard, or 5cm plus the material thickness? Ther blade guard should be adjusted as close as possible to the material being cut. The advantages of knee-height or foot-operated e-stops are that they can be operated when both hands are occupied (e.g. by holding a workpiece). However they are less accessible to persons other than the operator. Regards Peter