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Bygone · Sep 11, 2012, 03:27 PM

If I have two equal coil springs, and I compress the first one two inches, can that stored energy be used to compress the second spring two inches ? In other words can the first one relax and compress the second an equal distance ?

smoothy · Sep 11, 2012, 04:39 PM

No... think about it a bit and you will figure out roughly how much you would get and why.

Bygone · Sep 11, 2012, 05:51 PM

Are there no simple machines that you know of that will enable my scenario ? I understand that the springs would settle at equal tensions, is there no combination of levers you know of to accomplish this ? And thank-you for your time : )

smoothy · Sep 11, 2012, 07:02 PM

For that to happen you would have essentially invented the perpetual motion machine. Which can't exist. Unless I am misunderstanding the exercise you are trying to accomplish.

The springs would have something a little less than half of that transferred before they hit equilibrium... due to losses from friction etc.

Bygone · Sep 12, 2012, 03:37 AM

If a person had discovered a lever that would do this, would it be a " big deal "?

smoothy · Sep 12, 2012, 04:40 AM

Originally Posted by Bygone

If a person had discovered a lever that would do this, would it be a " big deal "?

Unless they somehow managed to defy the basic laws of physics, it couldn't exist.

Bygone · Sep 12, 2012, 04:55 AM

I'm very pleased you took the time to respond to my question, I wanted to be sure that I did not unknowingly overlook a device which is widely known to already be out there. I must say I am very pleased to hear your answer, hopefully your thinking on it is the only one out there. Once again thank-you very much, have a great day : )

smoothy · Sep 12, 2012, 05:20 AM

Originally Posted by Bygone

I'm very pleased you took the time to respond to my question, I wanted to be sure that I did not unknowingly overlook a device which is widely known to already be out there. I must say I am very pleased to hear your answer, hopefully your thinking on it is the only one out there. Once again thank-you very much, have a great day : )

You too... this really doesn't require a Mechanical engineer to answer... actually anyone that has had an advanced Physics course could do it.

The key points to remember there are differences between theoretical and physical realities, there are always losses in transferring energy and thus you will always have somethiing less than you began with, in some cases you end up with a lot less, but never will you have 100% transferance though you might get close to it sometimes.

Example with the springs... one has 100 pounds of tension on it... the other zero, in theory you would end up with both having 50 because that's the point of equalibrium. In reality due to internal friction and heat loss of the material you actually end up with a tiny bit less than 50 pounds tension on both.

ebaines · Sep 12, 2012, 06:50 AM

The answer to your original question is yes - it's not hard to envision a mechanism that transfers the energy from the first compressed spring to compress a second. The first spring would end up in an uncompressed state while the 2nd is compressed. To smoothy's point there will be some loss of energy, so the 2nd spring would actually be compressed a bit less than 2 inches. Here's how it could work: if you compress the first spring, then connect it to the second and release it, the system will go into dynamic oscillation with amplitrude 2 inches - you can then implement a mechanism that would latch the system at the moment when the 2nd spring is compressed.

Bygone · Sep 12, 2012, 08:28 AM

I'm talking about a controlled compression using a two to one lever, which will only compress the second one half of the distance, unless there was a lever which could compress like a pair of pliers, a controlled two to one compression.

ebaines · Sep 12, 2012, 09:26 AM

Are you asking whether a system can be designed that causes both springs to be at equilibrium with the 2nd spring compressed 2 inches? The answer is no, but you can get close. Make the lever a 10:1 with the short arm positioned over the initially compressed spring and the long arm on the uncompressed spring and the equilibrium point will be with the 2nd spring compressed 1.98 inches while the first has relaxed to a compression of only 0.198 inches. Make the lever arm even more uneven and you can get closer - for example at 100:1 the second spring gets compressed to 1.998 inches. Perhaps that's "good enough" for your purposes?

**EDIT - oops! I'm afraid I made an error in my calculations - this won't work. See post #17 for correction.

chinninani · Sep 12, 2012, 09:37 AM

No if coil are of equal size and made with different materials.YES ,if the both are in contact and the second is fixed.If they are not ,it is impossible to compress but it can push.

ebaines · Sep 12, 2012, 09:39 AM

Originally Posted by chinninani

No if coil are of equal size and made with different materials.YES ,if the both are in contact and the second is fixed.If they are not ,it is impossible to compress but it can push.

I have no idea what you're trying to say. Please clarify.

chinninani · Sep 12, 2012, 09:50 AM

The first cannot compress the second if they are made up of different materials.
It is possible only when both are in contact and the second is fixed at the other side.
If the second is not fixed the first just pushes the other forward.

chinninani · Sep 12, 2012, 09:54 AM

Asking about possibility only. RIGHT!

smoothy · Sep 12, 2012, 01:06 PM

I still would say no, because if they are looking at theoretical absolutes discounting real world losses... you might, but only on paper, but in the real world practice I'd like to see how its ever been done in the history of man.

If you can go one way then you could go back the other way and then you have the impossible perpetual motion device...

Not at all being argumenative... this is genuine interest, because if there is a way... I'd love to see it drawn out... ( Because I've tested in the top 1% on the Armed forces battery aptitude test or that the heck ever they were called)... on most of the categories. I can see things intuitively many people can't be taught...

I'm not a mechanical engineer but I've had college level advanced physics classes when I got my Electronic Engineering degree.

ebaines · Sep 12, 2012, 02:08 PM

Smoothy - you seem to be focusing on whether this would be a perpetual motion machine - but I don't get that from the OP's question. Maybe I should read more between the lines...

However - I think you are correct about it being impossible to build a mechanism using levers to compress the 2nd spring by the same amount the frist spring was originally compressed and resulting in equilibrium. I realize now that I made an error back in post #11 - the most you can get the 2nd spring to compress is 1/2 the original spring compression. Messing with levers with different lengths on either side of the pivot will result in a smaller deflection of the second spring, not larger. So I think the only solution is the one using dynamic principals as I offered back in post #9.

smoothy · Sep 12, 2012, 02:25 PM

Originally Posted by ebaines

Smoothy - you seem to be focusing on whether this would be a perpetual motion machine - but I don't get that from the OP's question. Maybe I should read more between the lines...

However - I think you are correct about it being impossible to build a mechanism using levers to compress the 2nd spring by the same amount the frist spring was originally compressed and resulting in equilibrium. I realize now that I made an error back in post #11 - the most you can get the 2nd spring to compress is 1/2 the original spring compression. Messing with levers with different lengths on either side of the pivot will result in a smaller deflection of the second spring, not larger. So I think the only solution is the one using dynamic principals as I offered back in post #9.

OK... that's falling in line with that I believed... I just wanted to be certain that there wasn't something fundamental I was somehow overlooking. Because that was something that got stuck in my head (luckily it was a slow day) because I just couldn't think of a way it was possible. You know... like a song you are trying to remember the name of and its almost there but not quite?

I was focusing on perpetual motion because if one could do this.. one could also build one of those because this could power it.

Bygone · Sep 12, 2012, 05:16 PM

There would be one drawback that would require more thought to overcome, since the first spring would be fixed(pushing only in one direction), while the second would be compressed on both ends half the distance of the first spring, with both ends compressing half the distance of the first, it would equal the same distance.

smoothy · Sep 12, 2012, 05:18 PM

Originally Posted by Bygone

There would be one drawback that would require more thought to overcome, since the first spring would be fixed(pushing only in one direction), while the second would be compressed on both ends half the distance of the first spring, with both ends compressing half the distance of the first, it would equal the same distance.

Won't work... because halfway you will hit the point of equilibrium and not gain any further compression, no matter what leverage you use. And that is completely ignoring any form of loss you will have in the real world.

Second problem is with #1 compressed 2" and #2 needing to be compressed 2" and both springs being equal... you really CAN'T use any mechanical advantage because you will never get the 1:1 ratio required. There is no workable solution without adding additional external energy beyond what's stored in srpring #1.