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emergency stop bar

taycat

Active Member
Active Member
#1
not sure if in right place.
hoping to get workshop set up again soon.
kids want to use lathe again and rather than standing with hand over em switch want to fit bar they can knock with knee.
i know some lathes have foot operated ones.
how hard are they to fit?
doesn't have to fitted to lathe can be fitted to stand.
needs to knee operated as they stand on platform to be at safe height for working.
 

markba633csi

Active Member
Active Member
#3
Sure you could arrange a microswitch with a bar tied to a latching relay or contactor-but
how big of a lathe are we talking about and how big are the kids?
would it not be easier to just move the existing switch so they could reach it easier?
Mark
 

taycat

Active Member
Active Member
#4
like the footswitch idea then i can use it as well.
they are 8 and ten and 4'3" and 4'6".
it's a clarke cl430.
the one in pic this pic is two yrs old and was taken after he had used lathe when using it he had sleeves rolled up out of the way.
couldn't take pic when using it as had hand over stop switch just in case.
tay1.jpg
 

woodchucker

Active Member
Active Member
#5
Sure you could arrange a microswitch with a bar tied to a latching relay or contactor-but
how big of a lathe are we talking about and how big are the kids?
would it not be easier to just move the existing switch so they could reach it easier?
Mark
Geez Mark, every time I look you have another avatar.
 

markba633csi

Active Member
Active Member
#6
Just restless I guess-
I really should go make something
M
ps my take on safety switches is by the time you hit 'em the damage has already been done,
also I think the hand is faster than the foot- it looks like the switch on the Clarke is in a perfect place.
 
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Linghunt

Active Member
Active Member
#7
Make sure any Safety / E-stop addition you add does the same function as all of the other devices on the machine.

That is an OSHA reg, that makes sense.

A Cable type E-stop switch might be better option for speed. Long bars for foot action seem to be the standard.
Finding the pocket foot switch in a panic, unless you have foot in there already.

Fastest device is the brain with solid safety practices and knowledge. When I'm using a table saw or band saw, I think about not cutting off my fingers or hand, a reminder that this bad boy can really hurt you BAD. A complacent mind of dangers tends to lead to bad things.
 

Uglydog

Active User
H-M Supporter-Premium
#9
the one in pic this pic is two yrs old and was taken after he had used lathe when using it he had sleeves rolled up out of the way.
View attachment 239665
Shop Gnomes. Wonderful things.

I've had two teenage neighbor boys this summer couple days a week. We are working through my old SMAW curriculum. Yep, every weld gets graded and redone until it's right.
Their mother reports she can't shut them up at dinner about everything they've done and their many failed welds. Evidently they are having fun...

Keep up the good work with yours!!!

Daryl
MN
 
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Linghunt

Active Member
Active Member
#10
FYI: NFPA section 10.7.2.1

The types of devices for emergency stop shall include, but are not limited to, the following

(1) Pushbutton operated switches in accordance with 10.7.2.2 and 10.7.3
(2) Pull cord operated switches
(3) Foot operated switches without a mechanical guard
(4) Push bar operated switches
(5) Rod operated switches

10.7.2.2 Pushbutton type devices for emergency stop shall be of the self latching type and shall have direct opening operation.

10.7.2.3 Emergency stop switches shall not be flat switches or graphic representations based on software applications.

Much more to it as well.
 

RandyWilson

H-M Supporter - Premium Content
H-M Supporter-Premium
#11
Cheap automotive two post lifts often have an overhead cable that is connected to the kill switch. Tug the cable and it pulls the "grenade pin" out of the kill switch. Cheap, available, and being cable the positioning of the runs are unlimited. You could do a box with the cable run around the work area, giving access high and low for multi-sized users.
 

Linghunt

Active Member
Active Member
#13
Light curtains are an amazing safety product. Just don't call them E-stop hardware.

As with other designs etc, do what you want, but when you label it E-stop then you got lots of hoops to jump through.
 

Silverbullet

Active Member
Active Member
#15
Just call it extra SAFTEY. You could use the foot switch as an open circuit till stepped on. Another words it won't run till you step on it. If you move it shuts off. It won't control the on/ off its just extra .
 

Ulma Doctor

Infinitely Curious
Active Member
#16
If you so desired, you could directly control magnetic contactors and the function of a machine tool with a footswitch
We do it everyday in my industry for meat processing
 

Uglydog

Active User
H-M Supporter-Premium
#17
FYI: NFPA section 10.7.2.1

10.7.2.2 Pushbutton type devices for emergency stop shall be of the self latching type and shall have direct opening operation.
Can someone please identify what self latching and direct opening means?

Thanks!!
Daryl
MN
 

tq60

Active Member
Active Member
#20
Often termed as a "dead man switch" a switch that is normal open is in series with the wire that controls the device.

Assume motor starter is a magnetic operator with a contactor controlled with normal start and stop buttons.

There is usually a loop wire to make the contactor latch.

The stop button usually is in series with that loop or the coil connection.

First hold stop and verify pushing start or run does nothing.

If so then locate a suitable foot switch that is normal open and close on press and wire it in series with stop.

Now one must stand on switch to allow running.

Lift foot and motor shuts off.

One also can use similar process but with a hand held device that forces one to have one hand busy holding it instead of resting on machine...

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 

RandyWilson

H-M Supporter - Premium Content
H-M Supporter-Premium
#21
Yeah, the whole system. You don't want the equipment starting back up when you let go the kill switch.

Two examples using the Cinny 1B

The drum switch on the head is inherently latching. You turn it to off, it stays off when you let go. The power buttons on the column are both momentary. They don't latch themselves. However, the wiring of the contactors they control is latching. Push the start button and the contactor closes. release the button, the switch opens, but the contactor stays latched closed. Push the stop button, the contactor opens and stays open until the start button is pushed again.
 

Linghunt

Active Member
Active Member
#22
Can someone please identify what self latching and direct opening means?

Thanks!! Daryl MN
Written by lawyer too. Part of understanding that stuff is knowing who wrote it and his definition of what different words mean. Not easy to do for me.

To be concise, My thought on the E-Stop Push button switch

-1- No springs in PB , latch open and closed
-2- Big Red mushroom top with lip so you can pull it back out after it is pushed.
-3- Proper labels ( Regs on that too I think)
-4- Location requirements
-5- different device is used to restart the system after e-stop event ( after the E-Stop PB is pulled out.)
-6- Contacts on E-Stop are typical Normally Closed in operational state. Goes open when activated. If a wire breaks it has same effect on system.
-7- functionality schedule ( how often is the system tested to be functional? probably a regulation on that)
-8- all E-Stops have to do the exact same thing with system. If you don't better have good documents and safety reviews as to why.


Typically , I wire my E-stops in one series string and then that drives a Safety relay. A separate PB is used to reset the E-stop string and safety relay. Feedback from each E-stop is run to computer system so the program can take action on the E-stop event as well. Program will act like it has to shutdown the system as if power is still somehow still there.

I like having power still on my PLC's and computers so I have use of programs and datalogging events. Typically have UPS's on them as well for same features as Power goes off when crazy events happen. [ had a ninja peaceful activist this year protesting capitalism and he climbed a power pole and was being all crazy, he fell off and hit power lines , shut the area down for a bit ]

Remember if something bad happens and you got dead bodies around, you will have investigators and OSHA hovering over you asking questions and looking to target someone for the event. Jail time and $$$ fines is the prizes to be given out.
 
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uncle harry

Active User
Active Member
#23
Many lathes have a mechanical foot brake, a long bar which is also connected to a NORMALLY CLOSED limit switch. This is only considered a stop function but it will quickly stop the lathe in an emergency situation. The unlatch function is essentially the same as a stop button in a typical relay logic latch rung circuit. This braking stop function can be very helpful when single point threading since the lathe stops very quickly and the operator can retract the cross feed in a less of a "panic" state. The motor stops both mechanically as well as electrically.
 

Uglydog

Active User
H-M Supporter-Premium
#24
Can someone please identify what self latching and direct opening means?
This is a huge help! And, it makes sense....
Thanks to all.
I was understanding this to somehow refer to the "can" or "enclosure".

It's discussions like this which teach me stuff and allows me to ask better questions, and do fun stuff more safely!

Daryl
MN
 
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