How accurate would this be?

cormie

I'm in the process of getting a waste application sorted out for my business so I'll be able to collect old sofas etc to bring to a waste facility, where it will be weighed and I'll be charged per kg.

I didn't think there was anything to help so I thought of a good invention, 4 little ramps for each tyre connected wirelessly to a display which I could show the customer before loading their waste, and then after, and charge by the difference, I googled and low and behold, my invention was already out, exactly as I pictured it, but costs a lot :eek:

I just found this and I'm just wondering if it would work and how accurate it would be. It says in the video if you're within 10% of your manual description it's good, but 10% is too big a gap for what I need it for I think.

Any other crazy methods to get the weight that don't involve spending thousands on equipment or spending 30 minutes doing these calculations?

Any feedback appreciated

LeixlipRed

Not sure this is in the right forum tbh. Engineering is your best bet.

Could you get a big flat scales for the back of the van which could either be moved out of the van for weighing stuff or else for when stuff is put on top of it? A quick google gave something like this: http://www.scalesexpress.com/product.php?productid=16533&cat=373&page=1

Not sure whether the llama comes with it or not though... there are some minus the llama for £224 or so, might be something you're looking for.

mathew

cormie wrote: »

I'm in the process of getting a waste application sorted out for my business so I'll be able to collect old sofas etc to bring to a waste facility, where it will be weighed and I'll be charged per kg.

I didn't think there was anything to help so I thought of a good invention, 4 little ramps for each tyre connected wirelessly to a display which I could show the customer before loading their waste, and then after, and charge by the difference, I googled and low and behold, my invention was already out, exactly as I pictured it, but costs a lot :eek:

I just found this and I'm just wondering if it would work and how accurate it would be. It says in the video if you're within 10% of your manual description it's good, but 10% is too big a gap for what I need it for I think.

Any other crazy methods to get the weight that don't involve spending thousands on equipment or spending 30 minutes doing these calculations?

Any feedback appreciated

Thats a pretty clever method for weighing a car. You have to make sure the the paper was exactly straight tho, and you got accurate measurements of the distances.

Dunno how forces dissipated in the suspension/bulging of the tyers when the load is added would affect it tho...
I theory I would think that resistance in the springs and rubber would affect your reading... I could however be completely wrong.....

Pines

mathew wrote: »

Thats a pretty clever method for weighing a car. You have to make sure the the paper was exactly straight tho, and you got accurate measurements of the distances.

Dunno how forces dissipated in the suspension/bulging of the tyers when the load is added would affect it tho...
I theory I would think that resistance in the springs and rubber would affect your reading... I could however be completely wrong.....

I think the method is pretty bogus, myself, though it looks plausible on the surface.

It assumes that each tyre is in contact with the ground over a rectangular area which is measured by the cards. In fact, only the treads contact the ground, and the actual area in contact with the ground is far less than the method measures.

The easy way to test it would be to repeat the method with different amounts of pressure in the tyre - say at 15, 20, 25, 30 and 35 psi, and see how much variation there is (I'm guessing the area won't change too much and the calculated weight will therefore increase at increasing tyre pressures when it ought to stay constant).

The next thing to test would be to add a known weight onto the vehicle and see how much the area changes. Again I'm thinking it won't change too much, so that the change in measured weight (= tyre pressure x measured change in tyre area for each tyre) will be an understimate ... and the OP will get hit with higher charges at the dump than expected.

cormie

Thanks for the replies, I was thinking the same too as when I've looked at my tyres from being an empty van to being a full van, they never looked that different.

Unfortunately the flat scales linked to wouldn't be good enough, it would need to cover the whole floor space of the van and if for example I had two sofas, one leaning on another with it's back leaning against the side of the van, wouldn't the weight be carried by the side, down to below the scales therefore not getting read? My invention idea would have been perfect, but look at the prices of what's out there at the moment :eek: http://truckscales.com/massload/wheelweighers1.htm

I think when you're dealing with something up to 3.5tonnes, the price is huge unfortunately!

Turbulent Bill

I assume you're only charged/charging by the weight of the waste rather than the total loaded weight of the van, so just weigh what you need. I'd use a dial gauge with a sling/harness as a weighing scales - think of the system used by fishermen to measure specimen fish, just on a bigger scale. This could be mounted on a simple tripod or even to the van. Big items like a sofa would have to be weighed individually, but you could group smaller items in a net to reduce the number of measurements needed.

From experience, vehicle weighing is surprisingly difficult and needs expensive equipment. Weighing just the load is much easier and more accurate.

DublinDilbert

If there was some system of measuring the deflection of the shocks this would give you a measure of the weight... This is used in alot of cars for self levelling lights, if you had this measure you could calculate the weight in the van i'm sure....

On some cars they have a hydralic valve which adjusts the rear brake assist based on the weight in the back of the car....

bushy...

Ask one of the lads that races in Mondello etc , they use portable gear to do cornerweights etc