Any electrical engineers here

ExRayTed

ExRayTed

ExRayTed

Soldato
Joined
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I'm not sure whether this is doable or not. What I'm after is a rotary style switch underneath a push button switch. The idea is that the rotary switch needs to be operated in order for the push button switch to work. A safety feature sort of thing. Once the push button switch is operated ideally it would self cancel the rotary switch back to it's normal state.

How easy would this be to implement and would anyone know what parts I'd need? Thanks in advance.
 
Not sure how similar these are to what you describe:

http://uk.farnell.com/eao/51-253-02...rch=Featured New Products&MER=i-9b10-00002068

But if anywhere has this type of switch as a mechanical component, Farnell should do.

If this exact operation doesn't exist as a mechanical switch, you may need to use a push/pull switched rotary potentiometer and some electronics to produce an operation approximating your requirements.
 
I think an E-stop button is exactly the opposite of what he wants, I think he wants a button that can only be depressed if a rotary ring on the outside is turned.
 
Does it need to be a rotary switch for any particular reason, as what you described is effectively a pushbutton with a lift top flap covering the button itself.
 
joemo13 said:
I think an E-stop button is exactly the opposite of what he wants, I think he wants a button that can only be depressed if a rotary ring on the outside is turned.
Click to expand...

Perhaps, but it offers the functionality by simply using a relay such that the 'reset' operation of the switch closes contacts and the push button switches off. It's not exactly to his spec, it isn't momentary and is 'cancelled' by pushing the button, but it would offer some safety as the switch needs to be twisted to activate the normally closed relay contacts.
 
Thanks for the help so far.I'm not sure I explained myself properly..I'm after a 2 switch setup, that's 2 physical switches, the rotary switch below the push button switch. The idea is that a potentially unsafe action could occur if the button was pushed accidentally.The rotary switch would in effect 'liven up' the push button. Once the button is pushed it returns the rotary back to its original position.
 
Yeah you can do what you are asking.
Buy a rotary isolator, and wire before your push switch.

Edit ignore that. Do you want the rotary switch to auto return to the off position?

If so you would need some form of contactor arangement so the first switch pulls in a contactor supplying the seccond switch and to de energise after the second switch is turned off.
 
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Usually circuits like this are based around supplying power to a relay coil via a switch, coil then pulls in the contacts which bypasses this switch and supplies power to the coil continuously
- coil is now latched on regardless of state of the switch.

A secondary button interrupts the coil supply, resetting this latch,
an additional set of button contacts on this secondary button could perform the function desired.

Power for function derived either from coil supply or via secondary contacts on relay.

It's probably a bit easier to draw, but basically a self latching relay circuit should work.
It's getting the sequence of set, reset right that's fiddly

C2C_latching_relay_3.gif



You can get momentary rotary changeover switches if that's what you really want, (http://www.thetoolboxshop.com/0-656-05-momentary-changeover-rotary-switch-15a-2350-p.asp) but like above, a flip top button sounds simpler.


I'm guessing you are thinking that a rotary motion is different from a push motion and therefore has to be a conscious action
 
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I'm pretty sure you can get rotary switches that use a spring to return themselves when you let go. You could use one and a push button in series - then you have to hold the rotary and press the button for it to work. What are you trying to stop by the way?
 
What about a key switch and a push button in series? That way you can only turn it on with the key in.

Either way, a simple covered rocker switch would work just as well.
 
I have only ever once used an E-Stop button in anger.
The other hundred or so times have been accidental presses! Thats just down to inappropriate placings though!
 
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