More help for K-9 - Punch tape system

[Dayle Hemsley]

Hi guys

 

Ok…..I have hit a snag with fitting my computer punch tape system into K-9.

 

I have worked out that I cannot put a spool of any kind in his head due to lack of space, therefore I will need to mount a spool ( with the punch tape wound onto it obviously ) inside his main body, then run a channel internally up his neck and into his head, it will then run under the antenna, light housing and blaster to the slot where the tape will come out.

 

The problem I have is that I need some form of channel that is very flexible to allow for some tight bends, in particular a near 90 degree turn at the exit inside his neck on entry into his head.

 

The channel material needs to very flexible but able to hold its rigidity so that there are no crimps that will make the tape snag as it is running up the channel. The tape is 1 inch wide so the channel needs to be a little wider than 1 inch to allow free movement on the sides as it travels.  The height needs to be fairly small, a few mm, around 5mm would be ideal. So that’s a bit more than 1 inch wide and about 5mm in height.

 

I have seen some plastic PVC oblong shaped conduit and some oblong shaped flexible steel conduit on image search. I have no idea where I begin to look for this type of stuff …..so….. if anyone has some bright ideas….please let me know.

 

Cheers

 

Dayle  

[Dayle Hemsley]

Hi Andy

 

5 inches across, about 6 inches longways from the back to the eye system, 1 inch either side of the mini miata antenna.

 

So the problem there is that the tape is 1 inch in width, if I offset the spool to either side of the antenna it still has a very sharp left or right turn to centre up for a straight run to the slot. As the spool can only sit to the side of the antenna any channel will need a very sharp bend to the left or right. The tape will definitely not do this.

 

If I mount the spool in his body and run a flexible channel up his neck I can keep the channel lined up straight with the slot all the way with the only bend being at the point on exit of the neck into the head where there would be a fairly sharp bend. On exit into the head the channel runs in a straight line under the antenna, eye system and blaster to the pinch roller mechanism for the slot.

 

There are some flexible PVC or stainless steel tubes I have seen on image search in Yahoo that flex very sharply but hold their shape on the turn without any crimping so the paper will still run up without snagging. To reload I should be able to hand feed the paper up the channel until it reaches the pinch mechanism at the slot, engage the motor so it grabs and then have this pull the tape up the rest of the way.

 

I just cant see any spool going inside his head at all.

 

Im stumped…..

 

Damn dog!

 

Dayle

 

From: Andy Gelme [mailto:an...@geekscape.org]
Sent: 05 May 2013 11:45
To: Dayle Hemsley; Stuart Young; John Spencer
Subject: Re: [CCHS] More help for K-9 - Punch tape system

 

hi Dayle,

On 2013-05-5 11:23 , Dayle Hemsley wrote:

I have worked out that I cannot put a spool of any kind in his head due to lack of space

Yesterday, John dropped off several small servo motors for you.  They would need to be modified, so that they turn continuously.

What is the maximum size of the empty cavity in K-9's head, please ?
 

The problem I have is that I need some form of channel that is very flexible to allow for some tight bends, in particular a near 90 degree turn at the exit inside his neck on entry into his head.

My gut feel is that this is going to be unreliable (stuck tape) and difficult to load new tape.

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[Michael Sullivan]

3D Print some cable chain at the correct size you need like vthis

http://www.thingiverse.com/thing:10915

Mick

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[Luke Weston]

Something like this?

http://www.cabletiesandmore.com/igus.php

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[Stuart Young]

While the igus stuff is nice for cables, it's not great for feeding stuff like tape which could catch in all the openings, especially if it's pre-punched for example. Also it'd be a right pain to feed the tape through if it runs out and all feeds through the mechanism.

For fixed bends and paths, perhaps we could 3D print something? Especially if the printed piece is ABS and then the acetone vapour method is used to smooth the tape path perhaps?

Note: There are various designs for the igus-style pieces you can download and print, such as Rob Gannon did for his Mendel Maxxed wiring, that might be able to be adapted for better feeding?

Stuart Young (aka Cefiar)

[damie...@gmail.com]

Presumably, there's enough room in K-9's nose/jaw to fit the motor/roller to pull the paper up from the roll.

A bit like the mechanism in thermal printer, such as a cardswipe terminal for EFTPOS/credit cards.

I was thinking that structurally, it doesn't need to be be very strong, but it needs to be continuous / without any places the paper can get caught on, and low-friction. It's just a guide. How about a sleeve made from three layers of felt sandwiched together, with the middle layer being thin strips that form "walls" on the sides of the channel? Or a tube of felt, ironed/pressed flat, and with the join in the middle of a flat side, so there's less of a pinch on the sides? 

Another alternative is to use a series of rollers and wire hooks/loops, each positioned at a point of inflection in the feed path, like inside a film projector or the thread-path in an overlocker. Again, this assumes you're pulling the tape under tension. I imagine this would be easier to re-load than any fully enclosed setup.

Damie...@gmail.com

[Luke Weston]

For the "conduit", how about something like a hose made of a rubber or vinyl like material of the right diameter? Simple and cheap, and continuous and smooth inside so there's nothing to snag on.

Cheers,

  Luke

[Michael Sullivan]

What about the large heat shrink tube and how it comes flat.

[Dayle Hemsley]

LOL…was just going to say I have some of that wide flat heat shrink (clear) that I can try. This stuff does crimp on tight bends though, but it depends how tight the bend is as to how much it crimps, in the end I need to keep this system as uncomplicated as possible.

 

dayle

[Russel]

Hi Daryl,

Do you know what shape the actual path will take?
A lot of the suggestions so far seem to over complicate whats required. I see the need for just a couple of thin strips of plastic (like what's used on shirt boxes/packaging etc) slightly wider than the tape and spaced slightly apart. A pair of pinch rollers near the exit slot to draw the tape through.
Are you planning on having the tape re-spool by itself? then roller and motor placement becomes more important.

Peter.

Just as another thought, I have worked on printing machines that printed on a ribbon of thin plastic film that we ran back and forth and turned it through right angles several times by running it over rollers placed at 45 degrees, you could do something similar and not need to place the spool of tape in the same plane as the exit slot. (now I guess I'm over complicating things)

.

On 5/05/2013 7:07 PM, Dayle Hemsley wrote:

LOL…was just going to say I have some of that wide flat heat shrink (clear) that I can try. This stuff does crimp on tight bends though, but it depends how tight the bend is as to how much it crimps, in the end I need to keep this system as uncomplicated as possible.

 

dayle

 

From: connected-commu...@googlegroups.com [mailto:connected-commu...@googlegroups.com] On Behalf Of Michael Sullivan
Sent: 05 May 2013 19:05
To: connected-community-hackerspace
Subject: Re: [CCHS] More help for K-9 - Punch tape system

 

What about the large heat shrink tube and how it comes flat.

 

 

 

On Sun, May 5, 2013 at 6:48 PM, Luke Weston <reindeer...@gmail.com> wrote:

For the "conduit", how about something like a hose made of a rubber or vinyl like material of the right diameter? Simple and cheap, and continuous and smooth inside so there's nothing to snag on.

Cheers,

  Luke

On 05/05/2013, at 5:35 PM, damie...@gmail.com wrote:

Presumably, there's enough room in K-9's nose/jaw to fit the motor/roller to pull the paper up from the roll.

A bit like the mechanism in thermal printer, such as a cardswipe terminal for EFTPOS/credit cards.

 

I was thinking that structurally, it doesn't need to be be very strong, but it needs to be continuous / without any places the paper can get caught on, and low-friction. It's just a guide. How about a sleeve made from three layers of felt sandwiched together, with the middle layer being thin strips that form "walls" on the sides of the channel? Or a tube of felt, ironed/pressed flat, and with the join in the middle of a flat side, so there's less of a pinch on the sides? 

 

Another alternative is to use a series of rollers and wire hooks/loops, each positioned at a point of inflection in the feed path, like inside a film projector or the thread-path in an overlocker. Again, this assumes you're pulling the tape under tension. I imagine this would be easier to re-load than any fully enclosed setup.

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[Dayle Hemsley]

Hi Andy and all.

 

Internally the power antenna in the head sits hard up against the back and with the head cover placed on there is about 1 inch of space between the top of the antenna to the head cover eliminating any possibility of fitting a spool as per Andy’s sketch. There really is no space in the head to fit a spool, the spool will have to go into the main body. Any guide track needs to very flexible at the point going up the neck into the head as this is an area that flexes a lot especially on the head movement up and down. A guide track can be made from styrene easily enough running from the spool to the neck entrance and from inside the head to the slot. But the point running up the neck and into the head cavity needs to very flexible which styrene will not handle.

 

The Hennig Stabiflex system looks ideal however looking at the measurements this stuff is too large and is only sold in long lengths.

 

Dayle

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[Clae]

Flexible electrical conduit?  It's a ribbed/rippled plastic cylinder so it holds its shape around bends.  I believe ebay seller motawizza in Brunswick has some rolls for cheap.