"Grounding out" question

[Rick_L]

In a recent tournament, which was using Triplette boxes apparently prone to this problem, all foil fencers with sweaty hands and non-insulated grips were grounding out when they hit.

Two questions:

1. How is this happening? I don't understand how the current is getting from the B line to the ground line through my sweaty hand. Shouldn't it still be going up the wire to the tip, before it can travel back down the blade to the grip?

2. What's the best way to insulate the grip? I bought a spray-on "rubberized tool grip", gave my grips several coats, and let them dry. Within five minutes of use, the coating was peeling off. Should I just put on several layers of spray paint? A thin layer of epoxy? Something better?

Regards,
Rick_L

[edew]

[quote]Originally posted by Rick_L:
<strong>In a recent tournament, which was using Triplette boxes apparently prone to this problem, all foil fencers with sweaty hands and non-insulated grips were grounding out when they hit.

Two questions:

1. How is this happening? I don't understand how the current is getting from the B line to the ground line through my sweaty hand. Shouldn't it still be going up the wire to the tip, before it can travel back down the blade to the grip?

2. What's the best way to insulate the grip? I bought a spray-on "rubberized tool grip", gave my grips several coats, and let them dry. Within five minutes of use, the coating was peeling off. Should I just put on several layers of spray paint? A thin layer of epoxy? Something better?

Regards,
Rick_L</strong><hr></blockquote>

This is a hardware problem and Triplette should replace some firmware chip. Make sure it's indeed a hardware problem by changing the sides of the reels and see if the same side on the machine is showing this grounding.

Triplette machines (once, don't know if it's still happening) has an overheating problem, as well, which also manifested itself with grounding, even when the fencers were not fully sweaty. Although, given that it was an overheating problem, it occurred when the room is hot, chances are the fencers were overheated and sweaty as well.

[Rick_L]

At the time, we didn't swap positions; I'll keep your advice in mind next time it happens. The problem was very intermittent (a fencer would hit, nothing would happen, he would hit again a second or two later, and get the light). In mid-bout, the ref had me reach out and hit my opponent - nothing. He took my foil, asked me to release my hand from the grip, hit my opponent, got the light.

Finally, the ref said we were grounding out due to sweaty hands, and said there wasn't much he could do about it. We finished the bout with perhaps every other touch not registering, both my opponent and myself swapping gloves as often as possible and learning the hard way "don't look at the lights."

[saberwillie]

hey there rick i have delt with the triplette boxes first hand i know Mr. Triplette and have asked about the problem. Fencer A is grounding out like edew said because fencer A's hand is wet and when the fencer makes an attack, he is squezeeing the grip tight and the sweat from his hand is causing the weapon to ground out. Either carry two gloves or use an exterior spray paint they works well but, u need put a couple of coats like once every two week or so. That works pretty well the better insulation you use the better off u will be. Sorry if it a little long winded <img src="graemlins/jawa.gif" border="0" alt="[Jawa]" /> <img src="graemlins/jawa.gif" border="0" alt="[Jawa]" />

[oiuyt]

K, who wants to explain the circuitry involved here.... If MY hand is wet and therefore my hand/glove/etc is electrically connected to my grip/bell/blade/C-line/ground, HOW does that make the touches that _I_ score ground out? I'm not clear on what's happening here, chip problem or no.... When my tip is depressed my tip, their lame, my wire, and my B-line are NOT connected to ANY of the above mentioned parts.

-B

[Methix]

I think what's happening is that your sweat is connecting your weapon to your lame and grounding A-C. Similar to if you put the weapon on your lame and tried to hit your opponent. I'm not an expert armourer though so this is just my hunch.

[Craig]

moving this to the armory

[Masterfulks]

We use duck tape to insulate the inside of all of our bells. We havent had a problem with grounding out due to sweaty hands since.......

[Rick_L]

Thanks Saberwillie, that answers #2.

Can anyone describe the path of the current as it grounds out this way? Without knowing this, I can't understand why Masterfulks advice would solve the problem.

To repeat the symptoms: hit while holding the weapon with sweaty hand, no lights. Release weapon, have someone else hit something with the still-plugged-in weapon, get the appropriate light. How is current getting from B to C? Or is it grounding out via some other path?

[Rick_L]

Methix: I just reread your post and realized you said A-C, not B-C. (Image: light bulb turns on.) So current is running from A-line > lame clip > lame > sweaty jacket > sweaty glove > grip > C-line? (Or vice-versa?)

[oiuyt]

What he's saying is that the sweaty person isn't scoring rather than the sweaty person can't be scored on. Grounding your weapon to your lame (through sweaty hands, glove, sleeve, lame) should NOT cause this, none of those things are part of the electrical circuit in question (sweaty person's B-line, socket, wire, tip, opponent's lame, A-line) nor are any of them in contact with any of the component's of the circuit.

Eric- you asserted that this is a Triplette chip problem. Could you explain the electrical connection involved?

-B

[damianip]

OK, I'm coming into this late but I'm confused.

Grounding your lamé with your weapon would prevent you from being scored upon except that the new machines detect this. If your lamé is grounded, then it would fail to record a hit: going to ground being preferable to going through the scoring circuit for the electrons involved.

If a person is sweaty enough: glove, uniform, and lamé damp and using an uninsulated grip then they could become part of a grounded circuit through their weapon and will not record being hit. However, newer machines measure this and compensate, or so I thought.

So is this machine failing to compensate for these various conditions? Seems so. Did the fencers have unisulated grips? Yes it seems so.

Isn't this why insulated grips and bell pads are required for foil?

Paolo

[ 04-10-2002: Message edited by: damianip ]</p>

[neevel]

All I'll say is that Triplette boxes have a rather well-earned reputation for flaky behavior (if you've got a spare half-hour the next time you're at a NAC where Joe Byrnes is working, ask him about it). There are reasons why they were replaced by SG-12s at NACs. Most decent scoring boxes from the last decade or so have no problem with normal amounts of sweat, and if problems do crop up it'll be due to a lame-to-weapon bridge causing the weapon to become valid target (which is how the anti-blocking logic is supposed to work).

The reason for the specification of insulated grips for foil was to prevent an A-C connection when the weapon came into contact with the lame. The rule actually only specifies the pommel or rear extremety of the grip be insulated, although fully insulated grips are often preferred to prevent sweat-bridge problems. Nowadays, with anti-blocking apparatus, almost nobody pays attention to the presence of insulation since you can't prevent your opponent from scoring a touch.

-Dave

[Mr. Foilist]

[quote]Originally posted by Rick_L:
<strong>Can anyone describe the path of the current as it grounds out this way? Without knowing this, I can't understand why Masterfulks advice would solve the problem.</strong><hr></blockquote>

I don't know which line is which so, I'll just call the line with the current running out of itthe "Hot line." The other will be called the "Ground."

In foil, current runs up the hot line through the wire. The wire then connects to the spring, which touches the base of the tip and forces this base up against the little support ring which is connected to the barrel via the screws. The current then travels up the wire, through the spring, into the support ring, into the screws, down the barrel and through the blade/guard/grip, and down to the ground line which goes back to the machine.

Now, when you press the tip, you are breaking the connection between the support ring and base of the tip, causing current flow to stop at the tip. The sides of the tip itself, even if they are metal, are insulated from the barrel. The bottom of the tip that touches the spring is connected directly to the flat disk part of the tip by means of a metal spoke that runs right through the center of the tip and connects to the underside of the flat part of the tip.

When you are grounding out through a wet glove/sleeve/jacket/lame', you are taking the current that normally travels through the guard and grip and allowing it to pass through your hand/sleeve/lame' as well.

Now, when this is the case, the current from your blade travels to the machine through the lame' line. I think the machine is designed to pick up on this. I think it recognizes the current from your weapon as current from the same side of the machine and cancels this current out. I'm a little shaky on this part, though.

This is just the same as putting your guard right up against the lame'. If your oponent hits the guard when it's like this, a touch will be registered (on some machines).

Now, since your lame is directly connected to your soaked glove by means of your soaked jacket, the target area is essentially extended to include your arm as well.

Some people are talking about not being able to score when this is the case. I don't see why that would be the case. Either way, when you press the tip, you breaking the ciruit and causing current to flow only through the tip and through your oponent's lame.

If you're the sweaty bastard that hits, there should be no problem. If you're a sweaty bastard and you get hit, true, your oponent's current will want to flow through your ground line by means of your sleeve. But, itsn't there still current flowing through the lame' as well? Don't modern machines pick up on this somehow and register the touch anyway?

I have a diagram of the inner-workings of the tip if you want me to post it. I just have to get it off of my home comp and convert it to a jpg and all that crap.

[ 04-17-2002: Message edited by: Mr. Foilist ]</p>

[Rick_L]

Thanks for the post, Mr.Foilist, but the odd thing (and what I still don't understand) is that it was the sweaty bastard that hits, who was grounding out.

This happened after a halt, when I hit my opponent and nothing happened:
1. Director asked me to hit opponent again. I did, center of lame, without getting any lights (as if circuit isn't breaking).
2. Director took my blade, asked me to let go of grip.
3. Director extended weapon to opponent's lame while I'm not holding it, hit lame, got colored light.
4. Director said "you're grounding out through your glove".

I suspect that you're right, though, about the underlying cause of the problem: the B-line current (hot) is returning via my A-line (lame), instead of / in addition to the C-line (ground), and the Triplette box is doing something it shouldn't (short the entire circuit for that fencer) in this circumstance.

Rick_L

[Mr. Foilist]

[quote]Originally posted by Rick_L:
<strong>This happened after a halt, when I hit my opponent and nothing happened:
1. Director asked me to hit opponent again. I did, center of lame, without getting any lights (as if circuit isn't breaking).
2. Director took my blade, asked me to let go of grip.
3. Director extended weapon to opponent's lame while I'm not holding it, hit lame, got colored light.
4. Director said "you're grounding out through your glove".</strong><hr></blockquote>

When this happens, I highly recommend hitting the machine until it breaks to pieces while the ref isn't looking (you'll have to get your opponent to distract him for you). Then, when he turns around, he'll see that the machine is broken and he'll have to get a new one. Bingo, problem solved.

[fred]

On this topic, our club has an Eigertek box, and tonight to my surprise, when I grounded the weapon to the lame, it prevented my opponent from scoring. The yellow LED grounding light went on, but I was still immune to touches. I thought with the new boxes that what was supposed to happen is that the lame & weapon would be live target.

Is something wrong with our box?

[neevel]

[quote]Originally posted by fred:
<strong>On this topic, our club has an Eigertek box, and tonight to my surprise, when I grounded the weapon to the lame, it prevented my opponent from scoring. The yellow LED grounding light went on, but I was still immune to touches. I thought with the new boxes that what was supposed to happen is that the lame & weapon would be live target.

Is something wrong with our box?</strong><hr></blockquote>

I'll test this out myself next time I'm at practice-- if this is the case, then it's a bug that should be reported to Eric or Dieter.

How new is the fimrware in your box (i.e., when did you get it, and have you installed the most recent upgrade chip if it's one of the earlier ones)?

-Dave

[peircer]

We put one of the upgrades in it last summer, I think it was for some of the new sabre timing changes.

[neevel]

[quote]Originally posted by peircer:
<strong>We put one of the upgrades in it last summer, I think it was for some of the new sabre timing changes.</strong><hr></blockquote>

I tested the anti-blocking on my Eigertek with the latest official (v1.1) firmware, and there is indeed a bug in that the anti-blocking doesn't work (i.e., when you have an A-C short on one side, touches against that side do not register). I swapped in the older v1.0 firmware, and anti-blocking worked just fine with that. I've e-mailed Eric and Dieter to let them know about the bug.

-Dave