Top Slewing Luffing Boom Tower Crane

[Matt Joyce]

Hello,

I've been building this crane project, it's still a work in progress and I have a couple of question which I thought I'd ask you guys.

The slewing motor is a stepper, and the boom and load motors will be a couple of geared dc motors, or if that does not work, a pair of continuous servos.

I'll probably add some sensors or limit switches.

What micro-controller springs to mind for this type of use case?

I need to strengthen the platform, 3mm pla with no load is bending.  I might use metal rods, or Alu channels.  I might simply print a much thicker platform, like a box.

Is 3d honeycomb infill any better than rectilinear for resisting torque?

Thinking about counter weights which will hang of the back.  This should about half the maximum lift load, which I don't know.  So I was thinking of small modular weights.

- water, very modular but not very heavy.

- lead shot, fiddly

- melt lead and make nicely formed pieces, how?

- concrete, make a mold, dusty need to seal it.

- steel barings, fiddly but good mass.

- steal plates, yes but how?

- use batteries and power it from the counterweight  - Intriging.

Any thoughts?

[STEPHEN BUCK]

There's been a number of articles on this subject in the free on line magazine Model Railroad Hobbyist, go to their webpage, and put crane in search.  Plenty of great ideas.  PS.  The crane looks great

 

I'd be a bit wary about melting lead and lead fume

 

A tube generally offers best rigidity for torsion

 

Stephen

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[Andrew Larkin]

Regarding counterweights, maybe use lead shot but mix it with epoxy and mould it into a useful shape.

[Kris]

I'd just use a printed box filled with fine gravel and epoxy

You can get weights from fishing shops and car mechanics will give you the old weights off tyre balancing

Sounds like a great project. With regards to rigidity, how about carbon fibre thread?
I think adafruit sell it.
You can make the boom like a suspension bridge.

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From: Andrew Larkin <and...@arcadius.com.au>
Sent: 11 August 2017 09:29:55 GMT+10:00
To: sydney-h...@googlegroups.com
Subject: RE: [RnD] Top Slewing Luffing Boom Tower Crane

Regarding counterweights, maybe use lead shot but mix it with epoxy and mould it into a useful shape.

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Sent from my Android device with K-9 Mail. Please excuse my brevity.

[Iain Chalmers]

On 11 August 2017 at 09:47, Kris <kr...@sleepingplanet.com> wrote:

I'd just use a printed box filled with fine gravel and epoxy

Or alternatively just a box you can fill with lead shot or sand or water to something - I'd at least try not epoxying it if you use sand/gravel/leadshot - which'd give you the ability to easily change the weight. 

big

 --

You can get weights from fishing shops and car mechanics will give you the old weights off tyre balancing

Sounds like a great project. With regards to rigidity, how about carbon fibre thread?
I think adafruit sell it.
You can make the boom like a suspension bridge.

---

From: Andrew Larkin <and...@arcadius.com.au>
Sent: 11 August 2017 09:29:55 GMT+10:00

To: sydney-hackspace@googlegroups.com

Subject: RE: [RnD] Top Slewing Luffing Boom Tower Crane

Regarding counterweights, maybe use lead shot but mix it with epoxy and mould it into a useful shape.

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.

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[Praetorian_TMOTC]

I bought a toy crane that uses the battery box as counterweight.

[Matt Joyce]

Thanks, I don't know much about epoxy, but I suspect there will be a wealth of information and tutorials on youtube.

On Fri, Aug 11, 2017 at 9:30 AM Andrew Larkin <and...@arcadius.com.au> wrote:

Regarding counterweights, maybe use lead shot but mix it with epoxy and mould it into a useful shape.

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[shykitten55]

Not wanting to further complicate your options, you asked about melting lead shot and moulding it.

Although epoxy has been suggested, here is a suggestion from left field:
There is this stuff called "kinetic sand" you can buy at toy shops, and I have seen it used on Hackaday for doing just what you want, though I think it was tin, not lead.

However, I think the idea would work.

Just a thought.

BTW, love the crane.

[Matt Joyce]

I have some kinetic sand, at least the kids do.  Hmm.

I'm actually leaning toward a SLA battery.  Regular shaped, heavy, useful.  I'm somewhat tempted to have it on linear bearings/rod to change the position.

Do you have any idea about how I might measure the load being lifted?

M

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[Praetorian_TMOTC]

I would suggest you buy yourself a "force meter". Readily available on fleabay etc you can measure your load in Nm.