I am not opposed to safety and reasonable measures to help situations and equipment become safer, but some of this stuff goes way to far, to the point where it causes an un-safe occurence. Example: Our D6T - It has the seat sensor that prohibits movement of the tractor unless it detects weight on the seat. That in and of itself sounds reasonable, except if it detects no weight for a moment and then it is weighted, one has to set the parking brake, toggle the direction switch to neutral, release the parking brake switch, and toggle the direction switch before the machine will move. We do a fair bit of receiving articulated haul trucks with it, and often amongst trees or other obstructions, or sidehill locations, in which it is the dozer operators responsibility to ensure that the haul trucks can safely dump. We run two-way radios in the equipment and guide the trucks as needed. I find myself having to turn in the seat to see the circumstances and momentarily removing weight on the seat. The truck may be quite close to me. After telling the truck operator to dump I often need to move. Toggle the directional switch and go, except that if I lifted from the seat for a moment I now have to go through the whole procedure before I can move. In the event that the truck operator's radio has failed, channel selector got bumped, volume been turned down, etc. I sometimes need to move quickly out of the way. We have not had any accidents as of yet, but it could happen if I am not able to go through the whole procedure quickly enough, and usually I am not aware that I have de-weighted the seat and go to move before realizing that I tripped the sensor. I have tried to unhook the sensor with the thought of installing a jump wire, but as soon as I un hook the wiring harness the almighty computer detects that it is unhooked and throws a fault code. I suppose a resistor could be added to a jump wire and it may work, but that is above my knowledge level. Anyway, this is not a gripe against the manufacturer in particular, just an observation that the dumming down of society in general, often promoted by the good intentions of folks that have never set seat in a piece of equipment be it those who promote governmental regulations or just industry engineers, is in my opinion reaching the point of diminishing returns.
Momentarily unweighting a seat can happen really easily, especially as you say while turning/twisting in your seat to look to the side/rear etc. Ironically all the 'engineered' safeties have created a potentially dangerous situation...your last paragraph probably sums up the situation pretty well.
Half the stuff isn't actually about safety, but rather manufacturer's attempts to avoid liability lawsuits.
You need a fatter operator who is too fat to unweight the switch. Should not be that hard to find
Dang, I'm 220, thought that'd be enough!
I hate the thought of what a plaintiff's attorney could do with *that* in the event of an accident...
Perhaps doing "that" might prevent and accident though.
The world has gone upside down in so many respects, this is another example.
That's what I have always said. No accident = nothing to litigate. Vs. following dumb procedures and having an accident because of them.
I don't disagree, but I worry about being involved in somebody else's accident. Do you think a lawyer isn't going to try and convince the jury that a machine with a safety system intentionally disabled doesn't equate to a disregard for safety in general, which equates to owning at least part of the blame? They're good at that sort of thing. Again, I agree, for the reason stated above.
Depending on how complicated the circuitry is, you may be able to add a simple resistor-capacitor circuit to provide a delay. That way the seat sensor won't know you've gotten off the seat until you've been off for whatever time value you choose by selecting the proper resistor and capacitor values. As long as you sit back down before that time is up, the computer will think you've been on the seat the whole time.
Unfortunately, I would need help to determine what resistor-capacitor is needed. Or I guess I could go to Radio Shack and get an assortment, but I'd probably screw something up knowing me!
If it's on a canbus system, you can't fool it with resistors.
I think the lawyers frown upon you smoking dah canbus on the dozer.......... Sorry..........couldn't resist!!
Our tracked skid steer we changed the seat switch to a toggle switch. Get in it, hit the switch and ready to roll. Door switch and seatbelt switch still work as designed so if you leave the cab it will still lock everything out.
Going on about safety switches and dumb. Years ago I owned and operated a small dedicated forestry mulcher. I was called on to do some clearing between a major highway and a service road. A new very efficient safety officer rocked to do a prestart safety inspection, defected it because it didn't have cut out switches on the outside of the machine. A robust discussion took place where I laid out my case for not fitting them and the fact there was a funa spotter catcher working ahead of me and if the switches were tripped I then had no control of falling trees which could cause injury or death to the said person. We ended up in the project managers office where he and the SO said it was the company protocols and that was that. So I relented but on 1 condition. The principal would indemnify me and my business from any loss or injury or any other damage that was caused by the activation of the switches in writing. The manager told told me to get working, he'd sort the rest out. The SO got fired. Some times you have to stand on your digs and don't join stupid.
"I have tried to unhook the sensor with the thought of installing a jump wire, but as soon as I un hook the wiring harness the almighty computer detects that it is unhooked and throws a fault code." Have you tried actually installing the jumper wire and THEN clearing the code? It seem it would be no different then sitting back down in the seat and doing what ever it is that's done to reset the computer so the tractor can be operated? Just thinking out load here.
I understand the frustration in seat switches. I also appreciate Tones concern for inadvertently tripping an external E-stop. In that situation, I don't know what a funa spotter is, or how that operation takes place. I guess I would try to operate so that no men were in uatms way. I also realize this is not always practical nor efficient. I don't wanna come off as some safety nazi, but I do appreciate the safeguards engineered into the machine's. The manufacturers aren't happy about compromising their good name and reliability for some switches and devices that should have weeded out the Darwin award candidates long ago. But you have to keep in the back of your mind, every rule, device, lockout etc was thought up because someone was killed or seriously injured. Seat switches, for example. If an operator gets out of his machine and accidentally bumps a control on the way off/down or out, that person could be hurt badly. Dozens and rollers. When you throttled up and push or pull the travel lever, you're going without a continual input from you. So know you're in harms way and anyone else in its path. How you gonna mount a moving dozer to stop it? Or a roller for that matter? I'm not saying it's the only way, but I think it's easier to live with it than without. I never want to make 'that' phone call or get hauled into a courtroom for willfull negligence or worse involuntary manslaughter. Just a bit to think about.
By American standards, you're middle of the road unless your 5'2" lol
The 10-12 accidents and near misses you experienced won't be on trial though. The guy who defeated the safety will be.
Seat switches are a real problem. A lot of ladies struggle with them. I've seen one woman tote a sandbag up in the cab. She'd lower the seat, place the bag and run her shift sitting on a sandbag. Couldn't have been comfortable. But she engineered her own work-around thinking her problem was unique.
Most safety systems I've encountered are simple on/off switches that simply unlock a solenoid or signal an ECU that a condition is met. The 'dumb system without an ecu should be easy, the more advanced (sequenced) you're gonna struggle with. The worst I can remember was New Holland LS skidders, you had to sit, lap belt, arm-bar then implement release switch. Go out of sequence, no go. I hated that little box.
No I haven't yet, but I think it will be worth a try. If done with the machine off it may work.
I would be fine with the seat switch if as soon as my weight was back on it all systems are go. The issue is that one must first toggle the forward/reverse switch to neutral, set the parking brake switch, then release the parking brake and toggle the direction before you can move. The time delay to do that is what is dangerous, not the switch cutout itself.
@funwithfuel , a funa spotter catcher is a person walking ahead of machines during clearing operations looking for and capturing native wildlife- Koalas,possums reptiles and birds and relocating them. Compulsory to have them on site in Queensland in some areas
All you need is a terminating resistor that's what we used at cat to run them with the seat out
That's not a parameter that can be turned off with ET is it?.........Evidently not now that I think about it or you wouldn't have been using a resistor. Sometimes I don't think before speaking (typing)!
LOL! Yeah they don't let me near anything electrical on the equipment. I can screw up a Macbook with just pushing the keyboard.
That's one of the reasons I run a 1970's track loader. No lock outs except the one you manually operate on the "H-L-N-R" lever. I programmed the only computer on board (my brain) to check the position of the metal flap that locks the lever in the "N" position before I leave the seat.
I know why they have the seat switches but I’m not a big fan of them. Many years ago at the cat dealer we had a D7 come in from a potash mine where the operator had fallen from the step to the track while the machine was reversing killing him instantly. We had the task of trying to determine how the machine could come into gear accidentally without physically shifting it. We found no issues with the machine. We found out that these operators had a habit of not stopping when they had to pee. They would stand on the step while doing the long reverse from the pile and just let her go on the track. Sad way to die.
Darwin effect.
My wife likes to say "Not enough farm machinery eating stupid people anymore......."
Seats should have voices. When a skinny light person sits in it..........it should say "Hey!.....eat more!" When a large heavy person sits it groans and says "Hey.....call Greenpeace."
Seen the same thing decades ago with scraper drivers letting it rip out of the cab door while flying down the haul road in 8th speed. The difference back then is that they were AFRAID to stop for a whizz otherwise they would get a chewing from the muckshifting foreman for "slacking".........
No it isn't. Had the same issues on new-model graders as well, espcially with lighter (generally female) operators. In the case of the tractor seat it uses an analogue pressure sensor (not like the switch on skid steers which is a simple on/off device) and I'm not sure whether or not a workaround is even possible. Furthermore the switch is not available separately, so if it ever goes on the fritz the solution is a replacement bottom seat cushion that comes complete with a new switch. With a Serial Number I could look at the schematic for that machine and give you a clearer answer.
DTD 00238. Thanks Nige!
Started around late 90s-early 2000s. At the DOT, the loaders had some safety Nancy thing and would beep if the seat belt wasn't on and email the boss for every beep That **** got ignored damn guick when we all put in earplugs and left it beep all night
In the ag industry, seat switches have been around for quite a while on combines and they will shut off the header/feederhouse and and shut off the unloading auger when triggered. ( The new combines might shut down more, I don’t have any experience with them.) But they only activate after a couple seconds so a person can get up momentarily to shift positions, etc. Locking up the machine the instant it is triggered seems dumb to me.
Same analogue pressure sensor that I posted above, and the same conditions apply. Illustrated a bit different on the electrical schematic but makes not one jot of difference - it works exactly the same way. Not available as a separate spare part.
Perhaps the solution is not a resistor but a clothespin on the sensor...
Unfortunately it’s not as easy as that. The sensor is moulded into the foam of the seat base cushion when it’s manufactured. Without cutting the cushion apart there is no access to it. Believe me the first one we failed we dug into with gusto to try for some sort of solution. Effectively you can’t access the sensor without destroying it.
I remember running into a problem on one dozer that would side hill real well. You could get on a slope cut and you'd end up in the corner of the seat and then the damn thing would get angry.
So if its an analog pressure sensor.....why couldn't you measure the resistance of the switch when someone was sitting in the seat?? Insert jumper wire with said resistor and Bob's your uncle........ehh?? Then you can throw the seat on the Tah Dun pile.
With macboocks, I don't have to push any buttons. Just being close to them will cause random crashes. Tractors have had them for at least 10 years. A farm that does a lot of baling on center pivots kept a box full of seat switches for in their service truck. First gear at idle is all you get if the switch goes bad in a Magnum.
Well it was a good thought