Highly Flexible Cable...

[Ricketty C]

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

 

[Bill Sloman]

On Saturday, August 8, 2020 at 11:02:09 AM UTC+10, 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.

If it is just flexing one direction, balanced flexible printed circuits work fine, HP used them in their X-Y plotters, and it got written up in the HP journal as having lasted for 10 million excursions when tested. In two dimensions you\'d need it to twist and bend, but if you stay within the elastic range you should be fine. The flexi did seem to need to be symmetrical about it\'s central plane - having the copper layer stretch as well as bend lead to early failure.

--
Bill Sloman, Sydney

 

[Jasen Betts]

On 2020-08-08, Ricketty C <gnuarm.deletethisbit@gmail.com> 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.

Mostly they use easily replacable cables

Hard drives, ink jet, and impact printers use flat flexible pcb.

--
Jasen.

 

[whit3rd]

On Friday, August 7, 2020 at 6:02:09 PM UTC-7, 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.

If it\'s a hinge flex, can you use a hinge pin which is a tube? Then the cable flex
is just a small amount of torsion on a protected length, if you thread the
cable through that tube.

Display hinges often have a few wraps of a flexible circuit cable around the hinge pin.
Those wraps slightly expand and compress in diameter, but don\'t kink at the hinge angle.

 

[bilou]

On 08/08/2020 05:07, Jasen Betts wrote:

Mostly they use easily replacable cables

Hard drives, ink jet, and impact printers use flat flexible pcb.

Using reversible cables is also a good way to extend their lifetime.
It applies to lawn movers ,electric guitars and even firemen hoses.

 

[Tim Williams]

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.

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

\"Ricketty C\" <gnuarm.deletethisbit@gmail.com> wrote in message
news:c6032dc3-db6a-4763-abd7-b798d8ba7e80o@googlegroups.com...

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

 

[server]

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.

--

Rick C.

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

Others have mentioned flat cable. I notice the more flexible cables use wire that has multiple strands of finer wire to give it more flexibility. If a strand or two breaks there are many more remaining to make up for it.

 

[Ricketty C]

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.

--

Rick C.

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

 

[John S]

On 8/8/2020 7:46 AM, Ricketty C wrote:

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?

https://en.wikipedia.org/wiki/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.

 

[Michael Kellett]

On 08/08/2020 02:02, 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.

In the days when we had phones with cords they used tinsel (copper tape
wound round cotton or other fibre).
I couldn\'t find anyone (easily) just selling 2 or 4 core stuff on reels.

http://www.lk-tinsel-wire.com/

http://atagcables.co.uk/tinsel-wire.html

A long time ago we made military telephone handsets which used neoprene
sheathed tinsel curly cables - only necessary for wide temperature range
- I\'m sure PVC will do you for ventilator temperature range.

MK

 

[Clive Arthur]

On 08/08/2020 02:02, 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.

I\'m guessing the switch is detecting a position rather than switching
significant current.

So you don\'t /need/ copper. Steel will flex without fatiguing, think
guitar string.

[I have several kilometres of four-core copper plated solid steel
conductor wire, each conductor is enamel insulated and overall wrapped
with waxed cotton. It\'s very thin and was intended for use in
wire-guided missiles, a totally mental idea.]

https://en.wikipedia.org/wiki/Swingfire

--
Cheers
Clive

 

[Lasse Langwadt Christensen]

lørdag den 8. august 2020 kl. 16.58.50 UTC+2 skrev Clive Arthur:

On 08/08/2020 02:02, 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.


I\'m guessing the switch is detecting a position rather than switching
significant current.

So you don\'t /need/ copper. Steel will flex without fatiguing, think
guitar string.

I believe some headphone cables are also steel for the same reason

 

[Carl]

\"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.

--
Regards,
Carl Ijames

 

[Ricketty C]

On Saturday, August 8, 2020 at 9:23:28 AM UTC-4, Michael Kellett wrote:

On 08/08/2020 02:02, 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.

In the days when we had phones with cords they used tinsel (copper tape
wound round cotton or other fibre).
I couldn\'t find anyone (easily) just selling 2 or 4 core stuff on reels.

http://www.lk-tinsel-wire.com/

http://atagcables.co.uk/tinsel-wire.html

A long time ago we made military telephone handsets which used neoprene
sheathed tinsel curly cables - only necessary for wide temperature range
- I\'m sure PVC will do you for ventilator temperature range.

I looked for phone curly cords but didn\'t find much in the off the shelf department. Kinda obsolete these days I guess.

I\'m leaning toward a 12\" or longer flat flex cable but that will require an interface board and other cable to reach the control board. I think it would also require some sort of clamp so the stress isn\'t on the connectors. PITA

A wire cable is probably a better choice but finding one with a rated lifetime is the problem. But it looks like we can use a continuous flex control cable and live rich, full lives.

--

Rick C.

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

 

[Ricketty C]

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

 

[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.

 

[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.

 

[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

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.

 

[Lasse Langwadt Christensen]

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

 

[Rich S]

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.