On Sunday, August 9, 2020 at 1:31:12 AM UTC-4, Michael Terrell wrote:
> On Friday, August 7, 2020 at 9:02:09 PM UTC-4, Ricketty C wrote:
> > We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm.  The arm swings through up to a 90 degree angle with most often a 60 degree angle.  
> > 
> > I know there are special cords that provide for this sort of flexing.  They use cables to connect to printer heads in 3D printers and laser cutting devices.  What do they use.    
> 
> 
> https://www.uniqueelectronics.com/index.php can make what you want. I helped them with a problem with custom SMA cables in the late '80s. I proved that their customer supplied coax was no good, by taking a handful of SMA hardline to the factory, and letting them look at them vs a new cable on their HP network analyzer. The engineer that I knew has passed away, or I would have given you his name.

Thanks

-- 

  Rick C.

  ++ Get 1,000 miles of free Supercharging
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On Friday, August 7, 2020 at 9:02:09 PM UTC-4, Ricketty C wrote:
> We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm.  The arm swings through up to a 90 degree angle with most often a 60 degree angle.  
> 
> I know there are special cords that provide for this sort of flexing.  They use cables to connect to printer heads in 3D printers and laser cutting devices.  What do they use.    


https://www.uniqueelectronics.com/index.php can make what you want. I helped them with a problem with custom SMA cables in the late '80s. I proved that their customer supplied coax was no good, by taking a handful of SMA hardline to the factory, and letting them look at them vs a new cable on their HP network analyzer. The engineer that I knew has passed away, or I would have given you his name.

On Saturday, August 8, 2020 at 8:36:02 PM UTC-4, Dean Hoffman wrote:
> On 8/7/20 8:02 PM, Ricketty C wrote:
> > We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm.  The arm swings through up to a 90 degree angle with most often a 60 degree angle.
> > 
> > I know there are special cords that provide for this sort of flexing.  They use cables to connect to printer heads in 3D printers and laser cutting devices.  What do they use.
> > 
>       Is telephone handset cable anywhere close to what you want?
>   <https://www.aliexpress.com/item/32748646228.html>

Yeah, I expect that could work.  Cut off one end to connect to the switch, plug the other end into the circuit board.  I guess I haven't seen these sold in a long time I figured they would be hard to get in large quantity.  I've also been focused on stuff that has specs.  That seems less interesting to these people. 

I found a company selling them and just sent a request for quote on 10,000.  I got an automated reply in a few seconds based on the 500 piece price and no delivery info.  lol  Maybe it will get some attention tomorrow. 

I think the mechanical issues might be something.  It will need to be attached to the arm in a way that keeps it from getting in the way of movements.  

Thanks for the prod. 

-- 

  Rick C.

  +- Get 1,000 miles of free Supercharging
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On 8/7/20 8:02 PM, Ricketty C wrote:
> We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm.  The arm swings through up to a 90 degree angle with most often a 60 degree angle.
> 
> I know there are special cords that provide for this sort of flexing.  They use cables to connect to printer heads in 3D printers and laser cutting devices.  What do they use.
> 
      Is telephone handset cable anywhere close to what you want?
  <https://www.aliexpress.com/item/32748646228.html>

On Saturday, August 8, 2020 at 7:15:50 PM UTC, Lasse Langwadt Christensen wrote:
> lørdag den 8. august 2020 kl. 21.07.24 UTC+2 skrev Rich S:
> > On Saturday, August 8, 2020 at 1:02:09 AM UTC, Ricketty C wrote:
> > > We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm.  The arm swings through up to a 90 degree angle with most often a 60 degree angle.  
> > > 
> > > I know there are special cords that provide for this sort of flexing.  They use cables to connect to printer heads in 3D printers and laser cutting devices.  What do they use. 
> > > 
> > > -- 
> > > 
> > >   Rick C.
> > > 
> > >   - Get 1,000 miles of free Supercharging
> > >   - Tesla referral code - https://ts.la/richard11209
> > 
> > Well, yes. Your everyday inkjet printer has a long ribbon cable leading from
> > the main board to the print head.
> > For example:
> > https://www.ebay.com/itm/Epson-WorkForce-Pro-WF-4734-Printer-Replacement-Print-Head-Ribbon-Cable/202811366906
> > 
> > A key issue besides the basic electrical and mechanical ones is "bend radius". The design, during motion, should keep the cable from making any "tight" bends.
> > The ribbon cable maker, I expect, would specify this radius. In the inkjets
> > I've seen, the ribbon cable is not held down so the flexing can occur over
> > a long portion of it length - which I suppose, evens out the stresses.
> > 
> > Cheers, Rich S.
> 
> that's a FFC, https://en.wikipedia.org/wiki/Flexible_flat_cable
> 
> not a ribbon cable, https://en.wikipedia.org/wiki/Ribbon_cable
> 
> I believe one of the 3D printers used a ribbon cable and it didn't last very long

Indeed! Thank you, Lasse.

lørdag den 8. august 2020 kl. 21.07.24 UTC+2 skrev Rich S:
> On Saturday, August 8, 2020 at 1:02:09 AM UTC, Ricketty C wrote:
> > We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm.  The arm swings through up to a 90 degree angle with most often a 60 degree angle.  
> > 
> > I know there are special cords that provide for this sort of flexing.  They use cables to connect to printer heads in 3D printers and laser cutting devices.  What do they use. 
> > 
> > -- 
> > 
> >   Rick C.
> > 
> >   - Get 1,000 miles of free Supercharging
> >   - Tesla referral code - https://ts.la/richard11209
> 
> Well, yes. Your everyday inkjet printer has a long ribbon cable leading from
> the main board to the print head.
> For example:
> https://www.ebay.com/itm/Epson-WorkForce-Pro-WF-4734-Printer-Replacement-Print-Head-Ribbon-Cable/202811366906
> 
> A key issue besides the basic electrical and mechanical ones is "bend radius". The design, during motion, should keep the cable from making any "tight" bends.
> The ribbon cable maker, I expect, would specify this radius. In the inkjets
> I've seen, the ribbon cable is not held down so the flexing can occur over
> a long portion of it length - which I suppose, evens out the stresses.
> 
> Cheers, Rich S.

that's a FFC, https://en.wikipedia.org/wiki/Flexible_flat_cable

not a ribbon cable, https://en.wikipedia.org/wiki/Ribbon_cable

I believe one of the 3D printers used a ribbon cable and it didn't last very long

On Saturday, August 8, 2020 at 1:02:09 AM UTC, Ricketty C wrote:
> We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm.  The arm swings through up to a 90 degree angle with most often a 60 degree angle.  
> 
> I know there are special cords that provide for this sort of flexing.  They use cables to connect to printer heads in 3D printers and laser cutting devices.  What do they use. 
> 
> -- 
> 
>   Rick C.
> 
>   - Get 1,000 miles of free Supercharging
>   - Tesla referral code - https://ts.la/richard11209

Well, yes. You everyday inkjet printer has a long ribbon cable leading from
the main board to the print head.

For example:
https://www.ebay.com/itm/Epson-WorkForce-Pro-WF-4734-Printer-Replacement-Print-Head-Ribbon-Cable/202811366906

It might be worth a look inside any inkjet model, just to get the idea.

A key issue besides the basic electrical and mechanical ones is "bend radius".

The design, during motion, should keep the cable from making any tight bends.
The ribbon cable maker, I expect, would specify this radius. 

In the inkjets that I've worked with, the majority of the ribbon cable is not 
secured -- it flexes over much of its length, so the radius stays large enough,
so the stresses are minized and get spread out. 

Cheers, Rich S.

On Saturday, August 8, 2020 at 1:02:09 AM UTC, Ricketty C wrote:
> We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm.  The arm swings through up to a 90 degree angle with most often a 60 degree angle.  
> 
> I know there are special cords that provide for this sort of flexing.  They use cables to connect to printer heads in 3D printers and laser cutting devices.  What do they use. 
> 
> -- 
> 
>   Rick C.
> 
>   - Get 1,000 miles of free Supercharging
>   - Tesla referral code - https://ts.la/richard11209

Well, yes. Your everyday inkjet printer has a long ribbon cable leading from
the main board to the print head.
For example:
https://www.ebay.com/itm/Epson-WorkForce-Pro-WF-4734-Printer-Replacement-Print-Head-Ribbon-Cable/202811366906

A key issue besides the basic electrical and mechanical ones is "bend radius". The design, during motion, should keep the cable from making any "tight" bends.
The ribbon cable maker, I expect, would specify this radius. In the inkjets
I've seen, the ribbon cable is not held down so the flexing can occur over
a long portion of it length - which I suppose, evens out the stresses.

Cheers, Rich S.

On Saturday, August 8, 2020 at 1:02:09 AM UTC, Ricketty C wrote:
> We are going to need a highly flexible cable on this vent project if we mount a switch on the motor arm.  The arm swings through up to a 90 degree angle with most often a 60 degree angle.  
> 
> I know there are special cords that provide for this sort of flexing.  They use cables to connect to printer heads in 3D printers and laser cutting devices.  What do they use. 
> 
> -- 
> 
>   Rick C.
> 
>   - Get 1,000 miles of free Supercharging
>   - Tesla referral code - https://ts.la/richard11209

Well, yes. You everyday inkjet printer has a long ribbon cable leading from
the main board to the print head. 
For example:
https://www.ebay.com/itm/Epson-WorkForce-Pro-WF-4734-Printer-Replacement-Print-Head-Ribbon-Cable/202811366906

A key issue besides the basic electrical and mechanical ones is "bend radius". The design, during motion, should keep the cable from making ny tight bends.
The ribbon cable maker, I expect, would specify this radius.

Cheers, Rich S.

  

On Saturday, August 8, 2020 at 12:25:04 PM UTC-4, Carl wrote:
> "Ricketty C"  wrote in message 
> news:9953c06c-d32a-4e6c-ac1a-ac93188de7a1o@googlegroups.com...
> >
> >On Saturday, August 8, 2020 at 6:55:24 AM UTC-4, Tim Williams wrote:
> >> Right, flat flex cables are nice, for simple in-plane bending motion like
> >> you get in a linear axis.  If more current (or better signal quality?) or
> >> more complicated motion is required, or just more signals in a smaller 
> >> cross
> >> section, go with multiconductor cable, high strand count, neoprene 
> >> jacket.
> >
> >What is special about neoprene?
> >
> >I figured there would be someone selling cable specifically intended for 
> >this sort of use.  I wasn't able to find anything with any particular 
> >specifications.
> >
> >This use only requires the cable to bend around a single axis.  No torsion 
> >is required.  We have a pretty fair length to work in.  In fact, the motor 
> >is on the other side of the bag from the control board, so if we use a flex 
> >cable we likely would either need something two or three feet long to reach 
> >or would need a local attachment point connected to the control board by a 
> >separate cable.
> >
> >This is all about not wanting to add a $20 position encoder to sense the 
> >specific position of the arm.  There are various failure modes that can be 
> >detected by knowing when the arm is expected to contact the bag vs. when 
> >air starts to flow (which we are sensing).  So either know where the arm is 
> >via a position encoder, or put a contact sensor on the arm.
> >
> >I also drew up a simple diagram showing how contact with the bag could be 
> >sensed via a "feeler" arm with a pivot point on the main arm translating 
> >contact with the bag to a point at the center of rotation.  Then the switch 
> >can be at a fixed position at the center of rotation without the flexible 
> >cable.  But that seems to be a bit much to ask the mechanical engineer to 
> >figure out.  Sounds to me like something fun to design.
> 
> Give https://www.mcmaster.com/flexible-cable a look.  They list several 
> varieties of cable meant for continuous flexing.

Thanks.  I think the problem is this is a well established matter and you need to have particular knowledge of what works and what doesn't.  I don't see any guides anywhere on specifics of this sort of design.  The data I find on the cables is a bit shy of the info needed to know what will work and what won't. 

Heck, the listing in McMaster seems to be a single company and doesn't even say what the stranding is in the conductors. 

-- 

  Rick C.

  -+ Get 1,000 miles of free Supercharging
  -+ Tesla referral code - https://ts.la/richard11209