Colorado Man Killed In Large Wood Chipper

[CT_Tree_Guy]

Island, I was thinking the EXACT SAME THING just yesterday. And I just thought of another one - a microphone connected to a microprocessor that shuts off the feed rollers when it hears the words "HEY!!!", or "STOP!!!!", or anything resembling the sound of a human being screaming. That would be very easy to hook into the existing autofeed circuitry of any woodchipper on the planet. Far-fetched? Well, when I call directory assistance and talk to their computer, it seems to understand me quite well.

I was talking to a Brush Bandit dealer two days ago who reminded me that many Bandit chippers have two "panic" ropes that dangle down inside the infeed chute that can be grabbed to shut off the feed rollers. Vermeer has never had these, but their new "XL" chippers have an new, additional safety bar along the bottom of the infeed chute that is much easier to reach than the standard one.

The more I think about the Colorado accident, the more I can understand how it might have happened. I always thought that I'd be able to reach the safety bar when I really needed to, but once you get yanked off your feet and are being pulled in at 120 feet per minute or more, all bets are off.

It would be interesting to be a "fly on the wall" in Vermeer's legal department since this accident happened. I'm not big on lawsuits, to say the least - but I'm beginning to wonder if they really did all they could to make their product as safe as could "reasonably" be expected.

 

[IslandTractor]

I don't know much at all about these commercial sized chippers but it does seem to be an area that is ripe for a high tech safety engineering review. "Safety bars" require input from the operator. As you pointed out, sometimes operators don't have a chance to react quickly enough. Electrons move faster than 120ft/sec feeders and microchips can be programmed to "think" faster than human operators in emergencies. My car has antilock brakes, stability control and air bags; each operating without my input to enhance safety. I wonder when we will start to harness "high tech" to improve the safety shut off devices of these horribly dangerous chippers?

 

[BillG_in_TX]

I think the technology exists - at least on a smaller level.

Check out this video of a hot dog weiner being pushed into a spinning table saw blade! /forums/images/graemlins/shocked.gif

Here's how it works. Now I recognize that a saw blade and chipper knives are two different animals, but maybe an adaptation is possible.

 

[IslandTractor]

Interesting. It actually might be easier to adapt this sort of technology assuming the electrical detection system could be adapted as the system just needs to stop the relatively slow moving feeder mechanism rather than a saw blade.

What I envisioned was a bit different and is based on the ability of simple infrared detection devices to quickly detect "warm" flesh entering the feed hopper. You could have a series of these miniaturized IR detectors ringing the inside of the hopper aimed inwards so they only detect living flesh inside the safety zone. I don't know what sort of brake would be needed but I imagine those brakes already exist they are just mechanically actuated by safety bars rather than electronically.

 

[CT_Tree_Guy]

The rotation of the feed rollers on a woodchipper is controlled in two or more distinct ways, each having to do with stopping or controlling the flow of hydraulic fluid to the feed roller drive motors.

The safety bar is connected to a hydraulic valve with three positions - neutral (no flow), or one of two directions of flow (feeding in, backing out).

The (electrically/electronically based) autofeed system would be the one most easily adapted to be used with the type of infrared, sound-activated, or any other type of switch or detector one might devise. The current autofeed systems operate on a variety of input methods, all performing the same function - applying 12 volts to a shutoff valve in the hydraulic system that stops the flow by means of a magnet that pulls a steel ball directly into the hydraulic flow, stopping it completely. When certain conditions are met (alternator output gets back up to a certain level, or an optical tachometer detects that flywheel rpm's have reached a certain level) the shutoff device is de-energized and hydraulic flow to the feed rollers is restored.

It strikes me as a very simple matter to devise a system that will apply 12 volts to the shutoff device until a reset button is hit, or the voltage is otherwise intentionally removed from the shutoff device.

In short, this problem is easily solved using existing technology. I'm sure everyone reading this has heard of "The Clapper"??

 

[BarryinMN]

Mine has rubber belt drive to a 330 Industrial V8 Ford. Even with the PTO lever in neutral it takes the blower blade drum mass 5 mins to spin down and stop.

It makes more dry oak eating noise than a mile long coal train accelerating /forums/images/graemlins/grin.gif My experience with the chipper is that it does the talking /forums/images/graemlins/confused.gif

Maybe a set of martha stewarts arm & ankle proximity bracelets wired to a airliner brake assy set to fire at 10x faster than the feed rate of 3 feet per second. On mine the active parts are 3 feet from the chute entrance giving 1 second total window. Hardware & code would have to determine a threat, confirm and activate positively within 0.1 sec without damaging anything. Then calculate ppm failure rates for each part added up with the universal set of variables /forums/images/graemlins/smile.gif

Didn't martha escape from the house & was caught by a photographer causing a judge to extend her sentence /forums/images/graemlins/grin.gif

A 36" pipe wrench might work but I wouldn't want to be anywhere near /forums/images/graemlins/grin.gif

 

[CT_Tree_Guy]

Barry,

Since your comments pertain to a woodchipper other than the type which uses hydraulically powered feed rollers to pull material in (the type involved in the accident that inspired this thread, and by far the type most widely used), I shall disregard them, except to say that I think that safety is a serious issue, to say nothing of death itself.

Any attempt on your part to make light of safety innovations which might easily spare another person from the same horrible fate as that suffered by Brian G. Morse will not be well-received by me.

John D.

 

[IslandTractor]

Tree guy, you are in the business. Don't you guys pester the manufacturers to improve the safety devices? Doesn't OSHA? It seems so unnecessary to have the machines continue to be this dangerous. Obviously there are huge forces and sharp objects involved with the chippers themselves but it certainly should be possible to do a better safety engineering job controlling the hydraulic feed belt.

 

[Hootie]

Chipper we use:

 

[Garrabo]

hope he didnt go in feet first /forums/images/graemlins/frown.gif <font color="green"> </font>