Why do Spools have 3 springs?

[Chief Rudiger]

Why do spools have three springs? One of the springs in one of our club's Leon Paul spools broke recently so I took it apart for a tinker. The thing still springs back and seems to work fine but without the width of the third spring the whole mechanism will be loose inside the case.

Interestingly, we have these weird homemade spools at our club that are just spools without cases, turned on their sides. The spindle is screwed into a heavy base plate at one end and supports an arm carrying the cable nozzle from the other.

They were old and forgotten about even before I joined the club and only one has ever been known to rewind… once. I think this is because they only had one spring each which got broken, but who knows.

Significantly, being free standing it doesn't matter how many springs you stick in it. It rewinds with one, two and three! I haven't tested it on a full piste yet though.

I wonder though, why do LP spools have three springs? I can imagine one could get sprung up pretty tight as you go along the piste but they are big, though coils, why do you need three? Two maybe, but three?

I ask because if we can put two new springs in each of these flat spools then we get another piste! However, if something nasty happens with less than three springs i might not hazard the working ones and just buy another to get the Leon Paul spool back and working again.

[telkanuru]

I'm pretty sure it has to do with space constraints. Uhlmann reels use one larger spring, for example, so there's more spring to tighten, etc.

[fencerbill]

How many rotations of the spring to move all the layers from the outside to the inside? Figure the average diameter of the wire on the spool. The circumference of the spool times the number of rotations gives you the amount of wire that can feed out of the housing. I estimate it will take two and a half springs to pay out all of the 20 meters of wire in a new LP reel.

Where is Barry Paul when we have questions like this?

From your description your weird spools may be actually old Prieur spools with their cases removed. Prieur spools don't have rotating contacts but have an arm with a small (one inch) wheel on the end of a rotating arm and then a second small wheel near the center. Early reels had the wheel axis horizontal but later ones had the wheel axis vertical and a snout on top. Russian reels are similar to the later Prieur reels.

[Joe biebel]

Sorry to go off on a tangent here, but from you post, I could not tell if your club is in a dedicated (used exclusively for fencing where the scoring equipment is always left out) facility. If so, you should consider a "reeless" system employing bungees or gravity for tensioning. You get rid of a lot of the mechanical (springs breaking) and a lot of the electrical (contacts wearing and corroding) problems, typically, for a fraction of the cost of reels. The upkeep time and and replacement parts is close to nil. The initial cost is low, in fact, a lot of clubs, like mine, build there own and have their own design. If you have to set up and take down each time you fence or train, the reel system makes sense and continuing to repair or refurbish the subject reels may make sense.

I would bet a search in this forum would give you several good examples of reeless systems

[fencerbill]

I'm pretty sure it has to do with space constraints. Uhlmann reels use one larger spring, for example, so there's more spring to tighten, etc.

Another difference is the larger diameter, which means circumference and wire length, of the spool holding the wire.

[Barry Paul]

At a three day competition with 1500 entries. Will explain why three springs at the end of the week. Barry P.S. the spool you describe was a cheap Leon Paul club spool designed to work with a shorter cable and from memory only two springs.

[Mergs]

The three spring arrangement is, as you say, a way to pack more springs into a smaller space.

The three springs are set up in cansisters so that they are independent of each other. That is, they are not connected directly to each other, so they act in series. As you have noticed when you took apart the reel, the spring canister consists of a back plate that has a square hole in it. The spring hooks on to this piece, while the inside of the spring is connected to a round hub with a square boss, or extrusion, on it.

The back of the first spring canister locks into the square key that is attached to the spindle. Since the spindle is held tight to the case, it does not rotate, neither does the first spring canister. The center hub of the first canister locks into the back of the second spring canister; the center hub of that one locks into the back of the third canister and the center hub of that one locks into the spool.

So now you have the three canisters hooked to each other and anchored on the one end by the case. When the cable pulls out it tightens the far left spring (closest to the spool), which after a while, will start to tighten the second spring and then the third spring (closest to the case). This is known as a serial hook up or “compound spring” system. If all three springs were hooked up to the spindle together, you’d not only be fighting all of them at the same time, but you would be limited by the amount you could pull them before you completely wound them tight around the spindle. Thus you are able to get our 20 meters of distance from a relatively small diameter set of springs.

Horizontal reels normally have a much greater diameter spool, the reason being that a lower profile of the reel is desired. Because of this it is possible to get sufficient force out of only one spring, although there are some designs that utilize multiple/compound springs. Vertical reels, however, also need to maintain a somewhat low profile, albeit, not as low as a horizontal reel, but lower nonetheless. To do this, and still have enough force to maintain the proper tension and reeling capability, thus it has three springs.

Hope this helps explain why these are designed the way they are.

[yeoldearmourer]

One thing not mention here the most common cause for spring breakage is over tighten the springs. On a Leon Paul system ten turns clockwise is enough to make the reel operate just fine. more then that you runthe rise of breaking a spring.