# Scroll bender switch problem in need of a solution ??



## Taildrager (Aug 17, 2013)

The plan was to use a band clamp around the yellow part . The band clamp would have a bump on it to activate a micro switch . By using the clamp it would be easy to time were it stopped by sliding the clamp around .
 All was well until it dawned on me that the scrolls will be more than 360 degrees . The plan that went south was to use a foot switch going to a mag start with a hold circuit to a drum switch to reverse the motor . Is there any way to hold the foot petal down until the micro switch passes the first time then remove my foot allowing the hold circuit  to hold until the micro switch stops it ?? Thanks Dommy i mean Donny:thinking::thinking:   P.S .     I thought i might add the scrolls i am bending are out of 3/4 solid round bar and i have a boat load of then to bend . The bender has the power to bend the bar stock 180 degrees around a 3/4 pin making a large hair pin. Having the capability of stopping the rotation at the same place will speed production and improve consist scroll shape


----------



## Tony Wells (Aug 18, 2013)

Put the stop switch wherever the ultimate stop point will be. Wire it parallel with the foot switch if it is a momentary contact style. They should be NC for the microswitch, NO on the foot switch. When you start the bend, have your foot switch closed, and the trip dog will open the microswitch with no effect. After it passes, you can release the foot switch, opening it. Then as the dog trips the microswitch this time, it is the only path, and will open and kill the contactor.

Clear as mud?


----------



## Codered741 (Aug 18, 2013)

This may seem too simple, but couldn't you just step on the pedal again?  Eg. 1 press/step = 1 revolution?  

Of course there is a way to wire the switch so that it stops only if the pedal is not pressed.  

This circuit will do what you want.  You will need a relay that has at least 1 extra, unused pole.  Looking at your setup I am guessing that you have a 110/220v motor, so a three pole single throw (3PST) relay will do what you need.  That specific combo is difficult to find, so a four pole, single/double throw (4PS(D)T) relay is what you will probably find.  Make sure that the relay has a sufficient amperage rating for the motor you will be using.  

(Sorry for the PaintCAD, I don't have my Electrical Design Software on this machine.... Also, the drawing shows DC power, not necessary, could be AC)


The lower Normally Open (NO) contact is on the relay, with the other poles that are controlling the motor.  The upper contact will be the NO foot switch, and the NC contact will be the stop switch.  

This circuit will run the motor as long as the foot switch is depressed, and only stop when the micro switch hits its stop, and the pedal is released.  

Of course, an auxiliary stop button would be in order, as an Emergency Stop, preferably as a separate relay system/dead-man pedal.  

Good luck! Don't hesitate to ask questions!

-Cody


----------



## Taildrager (Aug 18, 2013)

I think were on the right track ! I know for a fact that this tool will bend my steel but for two reasons i didn't want to stop until the scroll was completed . One is having to start under load [ i realize i could momentarily reverse direction ] but more importantly i have the belief that they will turn out more uniformly with out stopping ??  The first solution looks like the one but the water is still a little cloudy  the second may be just as good but the mud is a bit thicker it is my hope it will all become clearer when rereviewed ? Donny


----------



## Tony Wells (Aug 18, 2013)

They're basically the same solution, one described, the other also illustrated. Our explanations are just different ways of saying it, I believe.


----------



## Codered741 (Aug 18, 2013)

It is not completely clear to me, where things are not completely clear to you.  :lmao:

Starting under load, while not ideal, is entirely possible.  The main concern is that the amperage at startup will be higher, therefore increasing the wear on the contactor.  This is easily remedied by over-rating the contactor to double or even triple the required running amperage.  

I tend to agree with you about not stopping until the scroll is complete.  The circuit I provided will run as long as the foot pedal is depressed, and once released, stop at the designated point.  

If you have a question about anything specific, please let me know how I can clarify.  If you have the parts that you are planning on using, post a photo of them.  It will help us to help you!

-Cody


----------



## Taildrager (Aug 18, 2013)

I will try to describe what your looking at in the photos .To start  the bender gearing is mounted under one end of  a 4 x 10 table  with a 3/4 inch top.   All components are salvage the small motor driven box is 1 hp 40 to1 with 1406 inch pounds of torque , large g/b is a worm drive  50 to 1  69,000 inch pound of torque . Geared to a final rpm of 2.5 .  The coupler between the gear box an bender tooling is splined ag pto components . The one photo is of the under side of the table with the tooling disc dropped in . The top side photos show the recess were the disc drop in . The mandrills bolt or weld to the disc when not in use as a bender i will drop a blank in giving me a smooth top again .  The hub  has a nylon  bushing and i also am using a 1/4 inch disc of nylon under the 3/4 in steel disc very quiet even under load .  I will take some more photos of the gear box mounted when the camera comes home  Donny


----------



## Taildrager (Aug 18, 2013)

Of course, an auxiliary stop button would be in order, as an Emergency Stop, preferably as a separate relay system/dead-man pedal.  
!

-Cody[/QUOTE]

I know its not a dead man but the drum switch would stop everything if switched off but i do like the idea of a emergency stop button very much.   Would it require a separate relay or could everything be done with one of those ice cube relays ?  Donny


----------



## Codered741 (Aug 19, 2013)

> I know its not a dead man but the drum switch would stop everything if switched off but i do like the idea of a emergency stop button very much.   Would it require a separate relay or could everything be done with one of those ice cube relays ?  Donny



As long as your components are rated for the amperage that you will be using, the E-stop switch could be wired directly inline with the supply power.  If you choose to use a relay for the e-stop, you would not be able to run both the foot pedal control and the emergency stop on the same relay.  

Though it is not good practice, a STOP (not emergency stop) button could be made by wiring an NC switch inline with the coil, AFTER the latch/footswitch circuit.  It is technically not an e-stop, because it is not a redundant system, nor does it directly cut power from the machine.  The real idea is that if the relay for the footswitch were to weld itself closed, the E-stop, being a separate system, would cut power to the entire device.  

-Cody


----------



## TOOLMASTER (Aug 19, 2013)

you can add an interval 
	

		
			
		

		
	



	

		
			
		

		
	
 timer relay till you get past first bump/lobe/revolution

you other guys can verify this..i'm half asleep but i think i got it right..lol


also depending on how fast it is turning you may need a wider lobe in case the spool down drags past the lobe..


you can also make it do 2-3-4-5----- revolutions with the right timer..minutes/seconds


----------



## Codered741 (Aug 19, 2013)

TOOLMASTER said:


> you can add a delay on break relay till you get past first bump..
> 
> you other guys can verify this..i'm half asleep but i think i got it right..lol
> 
> ...



I think what you are referring to as a "delay on break" relay is commonly known as a timer relay.  This could certainly be an option, though adjustment for more spirals will be a trial and error process.  

The beauty of the latch circuit is that even if the lobe does not stop with the switch still struck, the circuit is broken, and the motor will come to a stop.  That is unless the foot pedal is depressed.  The only quirk is that if the foot pedal must be held long enough for the lobe to move off of the switch for the first revolution.  Otherwise the circuit will break as soon as the pedal is released.  In this regard, the lobe could be very small, enough so that the motor will coast past it upon stopping.  This way a quick tap of the pedal will start the motor.  

-Cody


----------



## TOOLMASTER (Aug 19, 2013)

meant interval  timer relay...you can get multi function also

timer relay is rather broad


----------



## BluCab (Aug 19, 2013)

Attach a small chain sprocket or a belt pulley to the device. Run a chain or link belt to a larger sprocket or pulley. Three to one or whatever ratio you need. Put a bolt or bump on the large sprocket and trip-switch on that. If you use a pulley, you can spring load it so to adjust the trip position. The spring will keep it tight during operation, but you can loosen it to adjust the trip location. 

If you use a bicycle chain and sprocket, you can use the "pedal-backwards" feature to adjust the trip point.


----------



## rdhem2 (Aug 20, 2013)

Good thought BluCab.  Fix it with a mechanical fix instead of electrical and it is easier for most to understand.  You could use a counter also and just count the bumps.

Foot switch activates the counter, signals the mag to go and when preset is reached, drops out mag.  Emergency stop button should be first device in the circuit.  Opening the entire control circuit not just the foot switch portion.  

The signals off these plug in type counters are usually a low voltage signal making the cord across the floor a much safer proposition when the cord is cut or wears out.  Never saw cords last long in a steel working environment unless a hard service type cord is used.  Even then good maintenance is mandatory.

Any chance of a overhead pendant to actuate the process?  Just a thought.


----------



## Taildrager (Aug 21, 2013)

Hope to take some more photos tomorrow now that the gear boxes are installed . The jury is still out but i think Tony and Cody have the most simplistic approach . It allows me to still incorporate the long hose clamp around the hub that will facilitate timing and complete change for different setups . And an E stop is also a good idea .


----------



## Glmphoto (Aug 21, 2013)

I know most will reject this idea for many reasons......Just a different take here so be nice.....  An encoder and a Basic Stamp or an Arduino or even a simple brick PLC.  Not the cheapest idea but by far the most control options.  I use BSII on a lot of projects cause its cheap and easy to implement.     Have a great day everyone


----------



## Codered741 (Aug 21, 2013)

Glmphoto said:


> I know most will reject this idea for many reasons......Just a different take here so be nice.....  An encoder and a Basic Stamp or an Arduino or even a simple brick PLC.  Not the cheapest idea but by far the most control options.  I use BSII on a lot of projects cause its cheap and easy to implement.     Have a great day everyone



That was actually my first thought, but the OP was looking for a relay based solution, so I didn't want to complicate it too much.  

I would use an Arduino/PLC with a prox switch to count sprocket teeth, and dip switch to set the number of teeth.  But I tend to over-engineer everything.  

This doesn't really need to be more complicated than the relays.  

-Cody


----------



## furpo (Aug 21, 2013)

Have you ever looked Allen Bradley Pico Controllers or there are numerous other brands out there.
Fully programmable, built in HMI, counters, timers, and relay outputs. Any time I can scarf one off Flea Bay for under $50 I grab it.


----------



## Codered741 (Aug 21, 2013)

furpo said:


> Have you ever looked Allen Bradley Pico Controllers or there are numerous other brands out there.
> Fully programmable, built in HMI, counters, timers, and relay outputs. Any time I can scarf one off Flea Bay for under $50 I grab it.



I personally steer clear of Allen Bradley.  Just a bit too proprietary for my tastes.  For personal projects, not professional, I like the Automation Direct PLC's.  The CLICK series of PLC's have free software, and all of the same features of the AB controllers.  

For professional projects, I use Beckhoff, or Siemens controllers.  Top notch stuff, can't beat it. 

-Cody


----------



## Taildrager (Aug 22, 2013)

What language is that ?? Is it like pie are round and corn bread are square ?):thinking::LOL:


      Really  say what


----------



## Codered741 (Aug 22, 2013)

Taildrager said:


> What language is that ?? Is it like pie are round and corn bread are square ?):thinking::LOL:
> 
> 
> Really  say what



I wish I could say this is the first time that someone has said that! 

PLC stands for programmable logic controller. They are very popular for industrial control applications, and are now becoming affordable enough for hobbyist use. They basically use relay logic, like we are using here for your project, but instead of having to wire everything specifically, you could just plug them all into the PLC and write a bit of ladder logic (code) to make the motor stop just right. 

This becomes more efficient as projects become larger and larger, the last project that I worked on was 110+ servo controlled high speed axes, all controlled by PLC's. 

-Cody


----------



## TOOLMASTER (Aug 22, 2013)

does this thing need to start and stop at any particular position.

do you have a picture of the bent part?


----------



## rdhem2 (Aug 23, 2013)

TOOLMASTER said:


> does this thing need to start and stop at any particular position.
> 
> do you have a picture of the bent part?



*WOW!*  The man with the sprocket has the best/simplest/cheapest idea.  Sprocket turning with teeth going by an inductive sensor being counted by a plug in counter.  Counter trips at entered preset from pushbutton/thumb wheel on the front of the counter.  Accuracy is only limited by the tooth spacing on the sprocket.  I had thought of the PLC angle but thought it over-kill for this simple a project.  I think even the so called smart relays they have out now have a couple timers and counters built into them.

Whether the sprocket is direct drive or turned via chain or belt, 1 to 1, or at a ratio it can be pretty accurate.  Heck if you used a 4 to 1 ratio you could divide the tooth spacing into quarters or whatever ratio you like.  Sounds pretty accurate for this job and affordable enough to build then tear apart for other uses when this job is over.  That is where a PLC really shines.  Operating a punch press today--a automated paint booth tomorrow!  Only limited by your imagination!

I love 'em and have installed lots.


----------



## Glmphoto (Aug 23, 2013)

Everyone has great ideas here, That”s why I really like this site. 
      I am glad my original comment has spurred some interest. The last BSII -or- Arduino I bought was very competitively priced. Well cheaper than the cheapest of PLCs. When you start adding up the real cost of materials they come in pretty close to any of the other ideas and deliver a lot more control options for the money. Of course all the ideas, be they low tech or high tech will work and the guy doing the job has to chose his own road.  We all have scrap metal laying around we make things out of and always call it "free". Some of us are the same way with electronics. For me a BSII and a couple sensors are laying around. We all weigh these things out on our projects. 
        In reading the comment “Sprocket turning with teeth going by an inductive sensor being counted by a plug in counter.” I wonder if a plug in counter, and inductive sensor and a sprocket are in fact so much cheaper than a BSII and an encoder or if its favoring the familiar. Don’t get me wrong here….I don’t care how its done and I don’t sell Microprocessors for a living..LOL…  I just like to see people step up there game and this site has some very imaginative people.
        Have a great day all!!!!!   (((SMILE)))


----------

