# emergency stop bar



## taycat (Aug 13, 2017)

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.


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## Ulma Doctor (Aug 13, 2017)

you can add a footswitch to the power cord.
there are some import footswitches that are inexpensive like this....

http://www.ebay.com/itm/AC-250V-15A...429077&hash=item3ae6bb1ce2:g:7ecAAOSw5cRZOCqA


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## markba633csi (Aug 13, 2017)

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


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## taycat (Aug 13, 2017)

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.


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## woodchucker (Aug 14, 2017)

markba633csi said:


> 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.


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## markba633csi (Aug 14, 2017)

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 (Aug 24, 2017)

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.


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## Uglydog (Aug 24, 2017)

Ulma Doctor said:


> you can add a footswitch to the power cord.
> there are some import footswitches that are inexpensive like this....
> 
> http://www.ebay.com/itm/AC-250V-15A...429077&hash=item3ae6bb1ce2:g:7ecAAOSw5cRZOCqA



Great!
Now you got me wondering if I could wire the 2 wire plus ground, covered pedal switch through the control voltage of a 3phase magnetic starter.

Daryl
MN


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## Uglydog (Aug 24, 2017)

taycat said:


> 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 (Aug 24, 2017)

_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.


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## RandyWilson (Aug 24, 2017)

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.


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## kd4gij (Aug 24, 2017)

You could use a light curtain.


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## Linghunt (Aug 24, 2017)

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.


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## Ulma Doctor (Aug 25, 2017)

Uglydog said:


> Great!
> Now you got me wondering if I could wire the 2 wire plus ground, covered pedal switch through the control voltage of a 3phase magnetic starter.
> 
> Daryl
> MN


yes sir you can


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## Silverbullet (Aug 25, 2017)

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 .


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## Ulma Doctor (Aug 25, 2017)

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


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## Uglydog (Aug 26, 2017)

Linghunt said:


> _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


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## RandyWilson (Aug 26, 2017)

Uglydog said:


> Can someone please identify what self latching and direct opening means?
> 
> Thanks!!
> Daryl
> MN




When the switch is operated, triggered to the open/off/stop position, it stays in the stopped condition when released until manually reset. It latches off.


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## markba633csi (Aug 26, 2017)

I think they mean the whole system; the contactor and button together latch closed to run and open to shut off when button is pressed
Mark


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## tq60 (Aug 26, 2017)

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


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## RandyWilson (Aug 26, 2017)

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.


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## Linghunt (Aug 26, 2017)

Uglydog said:


> 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 (Aug 26, 2017)

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.


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## Uglydog (Aug 26, 2017)

Uglydog said:


> 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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## uncle harry (Oct 21, 2017)

markba633csi said:


> 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



There are foot switches that are alternate action, that is one "tap" turns on and the next "tap" turns off.  You could interface higher loads with a contactor.


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## Linghunt (Oct 21, 2017)

uncle harry said:


> There are foot switches that are alternate action, that is one "tap" turns on and the next "tap" turns off.  You could interface higher loads with a contactor.



Those are amazing switches in the right application.  Can't remember who makes them, I remember buying them before thou.    

As stated earlier, be careful with whatever type hardware you decide to use with an E-stop.  The government regulation that term might cause a headache n the future.  The easy fix is to not call it an "E-Stop".


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## British Steel (Oct 22, 2017)

If your lathe has a no-volt-release for incoming power (which it should, IMHO), the stop bar can operate a normally closed microswitch wired in the NVR's coil return (in series with the existing stop button) built into the bar's pivot, or even better one each end so that should the bar twist when stamped on you have two chances for it to operate (to be sure, to be sure, as they say in the Old Country) - if you can link it to a brake to stop the spindle faster or another relay to e.g. operate the VFD's Estop* if you have one, it can make awkward threading jobs easier too?

A remote Estop's a good idea, so your loved ones don't have to step over your corpse and dodge flailing limbs to stop that annoying thump-thump-thump noise - again wire in series with the existing Estop circuit.

Dave H. (the other one - did the above while converting lathe, on the VFD, also linked in a "neutral" switch on the Fwd/Rev lever to disable the power-on button if it's "in gear")

* Most VFD's hold enough power with the input AC disconnected to brake to a stop in an emergency - YMMV!


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## 4GSR (Oct 22, 2017)

My e-stop is pull electric cord from receptacle.  I have most of my machines wired up with L14-30 receptacles and plugs.  Do have fused safety switches at each machine, too.


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