Flat Spiral Spring Compression

[Moulder]

Not sure this is 100% the correct place for this but hoping someone can help.

I have a flat spiral spring (similar to below) that forms part of a seat return mechanism that I need to put back in place. To do this I need to compress the spring but have not been able to find any tools/methods to do this.

Any suggestions how to do this gratefully received.

Thanks

[Munter]

I have no idea really but I think I'd try to put it in a vice and then tie it at the narrowest point on both sides....

I'm sure an expert will be along and say that's a really dumb idea though!

[smartphone hater]

Not had any experience with seat springs but normally the best way to tension a spring like that is to install it inplace with the two different parts of the mechanism disassembled, then by moving the parts to the position where they're fixed will tension the spring.. I hope that makes sense as it's a bit difficult to try & explain.

[Moulder]

smartphone hater said:

Not had any experience with seat springs but normally the best way to tension a spring like that is to install it inplace with the two different parts of the mechanism disassembled, then by moving the parts to the position where they're fixed will tension the spring.. I hope that makes sense as it's a bit difficult to try & explain.

Thanks for the reply. I see what you mean about how to tension the spring, the issue is that getting all my weight behind it I can move the outside hook about one eighth of the circumference. To get everything to sit right it needs to move half the circumference before the fixings can be bolted together.

It is a very strong and the default position is under tension, so really needs some sort of compressor. The only thing I can think of is a very big/strong jubilee clip.

[stoocake]

Would a piston ring compressor be any use?

[smartphone hater]

Yes a bit of a puzzle. I don't think simply compressing will help as the spring needs to be twisted with one end held stationary to compress. Do you own one of these? I'm thinking maybe something square up the centre square held in a vice & then this used to twist/compress, then you need to secure the compressed spring somehow & I know chunky cable ties to be amazingly strong. What ever you use needs to be easily removable once the spring is in place.

I am only saying what I would try & please be careful with compressed springs, if that releases unexpectedly it will go with a twang.

[Evoluzione]

Get hold of the end with a pair of pliers/molegrips and twist it round.

[stevieturbo]

Without seeing the entire mechanism and what you need to do, difficult to say.

But in it's most simple form, just grab the centre and rotate whichever way it's need tensioned.

[Moulder]

Thanks for all the replies so far. One thing that I am not sure comes across in the pictures is quite how strong the spring is, when in place it acts as the resistance/return for the seat, so is effective with a torso pushing against it the length of the seat back away from the spring centre. The spring resistance when using a pair of mole grips is very large.

Below is a picture of the spring in place. When fitting the hook on the spring starts where the yellow line is, and then needs to be rotated/compressed to the hook position at the top.

Looking at the image one possibility may be a longish pole with a bolt going through it into the hole in the centre, and another inside the hook of the spring. If it is the length of the seat back this will give a better lever, similar to the action of the seat back.

Any other suggestions gratefully received. Thanks

[stevesingo]

How about,

Push the seat back fully forward
Fit the centre of the spring to the base
Put a loop in a length of insulated wire place over hook
Sit in the back seat and pull, rotating the spring past the peg on the seat back and get an assistant to place the hook on the peg with a screw driver.

[stevieturbo]

So the spring pushes the seat back forwards ? to assist bringing it into the upright position from a reclined position ?

Only thing I can suggest is to tilt the seat as far forward as possible. Then maybe try and make up some sort of long lever system to crank the spring around before hooking the end into place.

ie, 2ft bar with perhaps a circle welded onto the bottom to encompass the body of the spring, and a dowel pin or similar to use as a hook.

Then that will give you the lever with which to compress, but it is not going to be easy.

[Moulder]

Thanks for all the replies. The spring is always under considerable tension, even when in its forward position which has the least tension. This is far too much to compress by hand to get the spring initially in place.

Below is what I ultimately used. It is a large jubillee clip with a cable tie between the spring hook and the clip fixing. When tightening the clip it compresses the spring, with the cable tie pulling the spring hook against the clip to aid compression. Once in place the cable tie was cut and the clip released.

It has not compressed the spring as much as I would have ideally liked, but was enough to get the spring in place with some tension on it. The next step will be to make a bar/lever as above if over time the compression is not enough.

Thanks again for all the replies.