Keeping Shocks under Pressure - Legal?

[Lipko]

Hi all!

What do you think, is it legal to keep the shock absorber completely compressed by default in a model? I want to make a boom where the lifting capacity would be (hopefully) increased by adding some shock absorber parts which would pre-lift the boom. This means that the shocks would be compressed most of the time, and this can lead to some relaxation.

I have no experience/knowledge how Lego springs (and the stressed assembly) behave in such conditions, and I wonder if it's considered legal or illegal.

Thanks for any comments in advance!

Edited October 14, 2014 by Lipko

[Blakbird]

Leaving a LEGO spring at solid height for extended periods of time should have no detrimental effects. The wire has not yielded at solid height, so this doesn't hurt anything.

[Anio]

Definitely illegal if totally compressed.

The natural position of shock absorber is decompressed. They can however survive if they are a bit compressed (by 10 or 20%), even on a long period.

If you consider sets like 8446, 8285, 8448, trans-clear shock absorbers / cylinders do break if fully compressed for a long period.

Lipko, as for your mechanism, you should look at the instruction of 10240.

[aol000xw]

The problem is the plastic, at least I can confirm trans-clear ones end breaking and regular ones at minimum bend. The spring however will happily recover its original shape with no sings of fatigue.

[dhc6twinotter]

I'd say that's legal and have thought about using a similar system myself.

[Blakbird]

I don't really think of the trans clear parts as shock absorbers, and those are not the parts I was talking about. There is absolutely nothing wrong with compressing the 6.5L shocks for any length of time you like. For the trans clear dampers, there are two designs. Early parts were prone to failure when the spring was compressed. The part was redesigned and the new parts are much better. I have many MOCs which use them and they have been fully compressed for years with no problems.

[SNIPE]

I'd say it is legal as lots of things, even in real life have 'spring pre-load'. Either because there not the perfect length or because it can be useful to have in order to push something outwards or to increase the force when it decompresses. That's why shocks sometimes have special nuts over them, - to compress the spring.

If you're bothered about it being broke don't do it. if your not then do it.

You can take the spring itself off the assembly as its just a clip holding it on and therefore put it over a regular axle - good for if there's too much or little room for a regular, spring assembly, or the wrong type/angle of connection.

So yeah, its just doing what it is designed to do, but for longer periods of time, even some official lego models keep it compressed to some extent.

Edited October 15, 2014 by SNIPE

[Lipko]

Thanks for the comments.

Yes, I am talking about the so-called shock absorber (see picture), not the more realistic and fragile transparent shock absorber dumper thing.

Edited October 15, 2014 by Lipko

[Sariel]

Note that the 42029 Pick-up set keeps springs partially compressed at all times. They got a wonderfully responsive suspension this way.

[PhyBuilder]

Everything has already been said. Like Sariel says, springs are sometimes under tension by design. On many mid- and highclass mountainbike shocks there even is a dial dedicated to do just that: preloading the positive or negative acting spring to adjust for the rider's weight and to adjust the reaction speed of the fork/shock.

Same goes for cars: lowering a normal car almost always implies more tension in the spring, this to improve the bottom contact the tyres have and to prevent the shock from bottoming out (like the rear axle on Sariels buggy sometimes did). One important note, just for the archive: only metallic materials remind their form. Over time, this doesn't apply to all kinds of synthetic materials (ABS, nylon, even polymere plastics).

If you use these under heavy weight (multiple KG) for months or years, for example as leaf springs, they will loose their original form.

[Rockbrick]

...so when they lose their original form you go to bricklink.....

[jantjeuh]

True, they're dirt cheap.