Focal lengths

[Burgerman]

Those into photography...

From my bed!
This is bunch of 1/4 sized images, that were all focused on the brass fire extinguisher valve. With 14mm, 16mm, 24mm, 35mm, 50mm, 85mm, 100mm,120mm, 135mm, 200, 300, and 400mm lens one after the other. To see the difference! All at 800 ISO except the 400mm one which was 25,000 ISO! (Mistake).

[martin007]

Great!
You received the camera.

[Burgerman]

It arrived at xmas. And a couple of lenses. You dont want to know how much. But its my hobby. Mostly paid for by selling previous lenses and camera body etc.

Now I just need a portrait lens. Not yet... Expensive. When my rainy day account gets back to the usual level! Will be at lest 6 or 8 months. People keep on sending me bills

[martin007]

Is the beam where you have the anchor placed steel or concrete?
How is the anchor attached?

[Burgerman]

Anchor?

Do you mean the orange scale for weighing?
Its a high carbon steel 12mm bolt passed through a10 inch (250mm) I section Lintel. It can hold a car up. This was once a large window.

Its a bit of this. Sat on a 11 inch thick brick wall at each end. Not going anywhere!

[martin007]

Do you mean the orange scale for weighing?

Yes!
Is the bolt welded or screwed on?

[Burgerman]

Its a high tensile M12 bolt. It goes in from the top, and has a nut screwed on the bottom followed by a 12mm lifting ring.

M12

[Burgerman]

So I can hang 192KG powerchairs on it.

[martin007]

Is it a manual traction hoist?
Don't you have an electric elevator?

[Burgerman]

Dont need one. A manual one is easy with a couple of fingers.

[martin007]

Have you raised the powerchair that hangs from the beam?

[Burgerman]

Yes. I do it all the time. To clean, swap tyres, remove motors etc. As needed.

[martin007]

Yourself or someone else?
Strong arms...

[Burgerman]

Its about gearing. It is super easy. About 3kg pull, lifts a 192kg chair easily. Takes almost no strength. Thats the entire point. A child can lift a powerchair with one hand. Around 50 to one ratio? 192 div by 50 = 3.92kg pull neeed.

Different hoists are different ratios. If you buy a 1000kg hoist, then its posible to lift 1000kg with one hand. Or if only lifting 192kg its less than 1/5th of that effort... So easy.

[martin007]

Which hoist do you have?
Where did you buy it?

[Burgerman]

Some shop online. Dont remember which. Years ago. Theres loads of different ones.

[martin007]

Are you saying that that model multiplies the force by 50?

[Burgerman]

Yes you pull the chain which is a loop, and it moves say 5 foot per handful. So it takes 10 handfuls of chain to lift 1 foot higher. With little effort. It was a guestimate. They vary. But its something like that. Chair goes up slow.

Are you saying you never came across a hoist like These before?

[martin007]

Exactly what brand and model is it?
I can't find any x 50 hoist for sale.

[Burgerman]

No idea. Its yellow! It might not be 50. Thats my estimate. Thats what it feels like. Its a 1000kg hoist.

Around 50 to one ratio?

Hence the question mark...
All I can tell you is that I can lift the chairs, with 2 fingers! But its not exactly fast... But I am in no hurry.

Yourself or someone else?
Strong arms...

You dont need strong arms! Its easy work.

[martin007]

How do you deactivate the brake to lower the load?

[Burgerman]

No brake of any kind fitted.
No need for one.
The weight of the chair compared to the effort/gearing needed to rotate the control chain isnt enough to lower the chair. Even at 1 tone or 1000kg.
Just pull the chain loop the other way to lower it. And its even lighter to pull.

[Burgerman]

Watch...
This one is bigger, and old. But works same way.

150 pound effortless lift with fingers!
No brake needed. It shows how it does this for itself. Cant fall or run away.


youtu.be/3j55IAg3GgE

[biscuit]

Can a cheap pulley system like this bear the weight of a wheelchair?
https://amzn.eu/d/2QQIBC4
For the garage. Would need a high rail to hang from. For about £15, Amazon also has a pulley lifter for storing a bicycle, but it would scarcely lighten the load.

[Burgerman]

In theory... It will be stretchy and hard work though and you will need to tie it up to prevent it falling. It isnt a proper lifting certified safe chain hoist. It might work in a fashion. But I wouldnt go near it...

With 4 pulleys it will give a leverage ration of 8x so if your chair weighs 190 kg like the salsa/Q700/Explore chair shown in my pic for e.g, you would be pulling that rope with 1/8th of that amount to lift it. So thats a serious 24kg. Or some 52lb which is a lot! It will actually be a fair bit more in reality due to frictional losses of rope on 8 pulleys and the pulley shafts. Maybe another 15 or 20lb. Is this possible? Yes. Is it practical? Not really.

These sorts of pulleys are what martin was imagining I think.

[martin007]

These sorts of pulleys are what martin was imagining I think.

That rope hoist model gives very bad results.
The feedbacks on the internet are clear.
It's like throwing 15 pounds in the trash.

[biscuit]

Suddenly I remember when I was about 10 years old a school friend lay under a foefie slide (I don't know what it is actually called) that he and his friends had made, a garden chair running along a washing line. As you do when you are 10.

The washing line and chair came down, a steel chair leg went right through him, miraculously without damaging anything vital.

My scheme above is scary!

[Burgerman]

IF its spec is accurate it would be safe. IF yu could lift it! But that looks like a bit of a nightmare.

At least a proper geared hoist is safety approved and certified. So safe even to get under it. And easy to lift.

[Burgerman]

This thread was about focal lengths!

[martin007]

This thread was about focal lengths!

You can change the title...