Glad you like it Mark. One a few analoigies I use to get the points across to my students.

Its amazing though, how many participants stare at my elbows and say it is supporting the pivot box. And I say..."do you see a pivot box on my elbows? They say... my arms, and I say..see any arms resting on my elbows? Now my arms ARE getting tired, and then someone will whisper... "nothing'.

Ta-da!!!! Now class, does anyone see anyhting on my elbows, and they all sigh and say 'No', and then I ask, so what are my elbows supporting? Nothing! And since my elbows represent the rear steer wheels, the rear wheels are not supporting anything either.

Easier said, then written. lol

Really like that method of explanation using the clenched hands and elbows. Very clever.

Well, I'd love to take a trip to Chicago in January (yikes?), probably slightly warmer than here in Ontario, however it is my 25th wedding anniversary next year and the wife wants a cruise. So come January, I'll be heading south to the warm waters of the carribean and Atlantic, for 10 days of warmth. Thanks for the invite tho'.

Where I live, forklifts are very ordinary. We don't see the extravagant machines and attachments that one would see in many other places. Our forklifts are your typical 5000lbers, with sideshifters, and that is it, other than the narrow aisles, power pallet trucks, some stocpickers and very few turret trucks. Keeps the training easy. With no excitement.

I trust they kept pedestrians out of the aisle when demonstrating the Bendi. :)

Makes sense. I never looked that closely at the rear suspension on a lift truck, probably because I can't fit my head under there.

I've been in operations using Bendi's but I haven't actually driven them. When you get up close to one, they are really strange when you are used to standard lift trucks. They are not that uncommon around here (I live between Milwaukee and Chicago) where they are popular in manufacturing plants. I have driven a swingmast (Drexel) and worked around turrets.

Sounds like you need a road trip to a trade show. Promat will be in Chicago in January and they usually have just about everything there. I recall last time they had a Bendi actually operating in a narrow aisle. I felt sorry for the operator that had to keep moving the same load all day long. I'm pretty sure I've seen the Aislemaster there as well and they usually have several brands of turrets. They may even have one of those all-direction airtrax lifts operating. I saw one operating one years ago at Promat and it was pretty cool (though I can't really think of a practical application for one). I believe that driving one is more like flying than driving (though they wouldn't let me drive it). They also had a hydrogen fuel cell powered lift truck there last time and I would bet they would have at least one this time as well. They also usually have a pretty good assortment of lift truck attachments on display (though they usually aren't operational) and a variety of AGVs. And if that isn't enough, last time they even had a full-scale operational automated trailer loading system on display.

Sorry if I got a bit off topic, but I always look forward to Promat (it comes to Chicago every two years).

3-wheel vs 4 wheel

The rear wheels of the four wheel forklift are not adjoined to the frame of the truck. No suspension, no struts or shock absorbers. Take your 2 hands and fold them together (finger thru finger). Swing your elbows out so your arms are parallel to the gound, and your clenched hands close to your chest. Your elbows represent the rear steer wheels. What are your elbows supporting? N-o-t-h-i-n-g!!!!!! As are the rear steer wheels of a 4 wheel sdcb forklift. However, where your hands are clenched, is known as the pivot box, which controls the steering of the rear steer wheels, and provides approx 3" of suspension to the rear of the truck. And its that pivot box that is the third and last support point on a 4 wheel sdcb fl.

That is how I explain why there are only 3 support points, not 4.

BTW, I have Powerpoint presentations for each and every class of forklift, except zoombooms, and I do explain the stability factors of each, separately.

And, I have never trained on a Bendi, yet seen one.

Thanks for the input.

I believe the "support points" of the "stability triangle" as often used in training programs are still the same (front wheels and center of rear axle), however in the case of a bendi, the triangle changes shape as the front end is turned (from an isosceles triangle to a scalene triangle).

But to be honest, I've never quite understood why a "stability triangle" is generically used in training for lift trucks. I expect a 3-wheel truck would have a stability triangle and a 4-wheel truck would have a stability rectangle (whereby, in the case of a 4-wheel bendi, would change to some type of non-square quadrangle). Any engineers out there have some input on this one?

The trickier part is demonstrating where the center of gravity is as the truck goes through the various stages of placing and retrieving loads. Instead of moving forward and back within the triangle (or quadrangle), it is also moving towards the side.

But again, I guess I come back to the fact that the engineers already figured out the maximum size and weight load that will keep the center of gravity within the support points (whether it be a triangle, rectangle, or whatever) for that specific truck under recommended operating procedures, and put this information on the placard on the truck. The stability triangle concept is used to help communicate where this information on the placard comes from (for example, why the capacity changes as the load is raised), but the information on the placard itself is the critical piece of information the lift truck operator absolutely needs to understand.

I think it's great if the operators have a thorough understanding of the physics, but I'm not sure I want to start bringing up scalene triangles and non-square quadrangles in a lift truck training session (I can just imagine the nervous stares I would get). So I guess I'm ok with providing a basic understanding of the physics combined with a thorough understanding of the placard and safe operating procedures. I would think your 35 minute presentation on support points and stability is still more than adequate for training with these other trucks provided you add that there are a few additional factors unique to these specific vehicles and just breifly explain the additional factors (such as the front axle turning on a bendi, or the mast swinging and shifting on a swing mast, etc).

Okay...then where are the support points?

The reason being is that I paint a true picture of what the forklift is 'thinking' as the operator works the truck. I intorduce the 3 support points on all (or now most) sit-dwon CB f/ls, then describe the center of gravity, and then tremendously well (pat myself on the back, sorta speak) I highlight the 4 major items that affect the center of gravity inside the stability triangle. I do this extremely well, even blows away the engineers. Believe it or not, the participants walk away understanding the physics of the truck inside out, and well.

It is too long too explain how I do it, on this forum, since it takes me 35 minutes of explaining, analogies, along with my Powerpoint presentation, to get it into their heads, but it works. As I said, although I do not know of any in my area, I was wondering tho', if I HAD to put a presntation together, what is the stability factors, as I initially asked?

I know these trucks steer from the front. There goes the rear pivot box (suspension, steering) theory, and since I would assume it drives from the rear (although I may be wrong), this truck is screwy.

Just looking for some input.

Thanks.

You are correct that the balance characteristics of these vehicles are more complex. Also the "bendi" types are different than swingmasts and turrets. From a training standpoint, I'm not sure that trying to describe it as a trapezoid or moving triangle is going to fly with students that often struggle to grasp the basic stability triangle concept of a standard counterbalanced truck. It does make it just that much more important though that the drivers are absolutely certain that the load is within the capacity of the truck for the height they are lifting it. Beyond that, if the workers understand that when they raise, swing, rotate, shift, or tilt the load, or move or stop the truck, they are impacting the stability of the truck, I think you will have accoumplished your training objectives.