Can This Vehicle Be Turned?

Is this homework? CR4 doesn't do homework.

1. Why don't you make a scale model and see what your physical size limitations are.

This could be done in a cad program.

2. talk to some trucking outfits. They have to be concerned about similar tight situations.

3. google turning radius and read up on some of the formulas

Hello ddk:

some useful advice in your short post!

I just did it by making a scale model and it will not go round!

How about looking at the fire departments ladder trucks has a steering axle on the rear to do just what you are looking for. The wheels are placed on the rear so the operator can negotiate the turn

Hello ozzb:

you need to get half the trailer round before you can 'steer' the back-end round.

With the extreme width you cannot get have of the trailer round anyway.

Good idea. But it is just too long by about 4'.

A lot of that which we were not given is where the pivot point of the front axle is. If the tractor is attached to pivoting axle. Its placement may help negotiate the turn.

Hello ozzb:

Thanks for the post.

I think Mark decided the 'tractor' will be fixed as per a normal flatbed, you know.

with the cab being half the width of the full sized rig, you can ignore the cab, as it goes round 'inside' the dimensions of the trailer anyway.

As I just mentioned to Mark, I think it could get into some nasty positions if there was two hitches. Alright going forward, but a whole different thing going back and forth? I have put the joint at halfway along the trailer and, have tried it on a scale model. sheets of paper, and it goes round ok. It is tight but a good driver and all you know will make it. And that is staying withing the 24' already given in the original post. It may be a few inches or even feet can be gained by letting the trailer ride over the path area where possible?

Well, it can't be done. The limiting case would be when the trailer is at an angle of 45° with both streets and the inside left of the trailer is touching the inside street corner and the outside right rear of the trailer is touching the far side of the street. The street would then need to be 27' sin45° + 16' cos45° = 30.4' wide at a minimum.

There's a furniture moving algorithm somewhere but I can't find it at the moment.

Hi, TVP45!

Lovely response. And I appreciate all the responses thus far, ddk, ozzb, and pwslack.

The 45^o problem was one that I encountered as well. So I made the question able to replace the positions of the wheel sets to wherever the response would want to place them; and allowed each set to have an independent steering (and even perhaps independent electric motoring with a hydraulic lift system so that for example, a set of rear wheels could be lifted clear of the sidewalk as the tailgate passes over it...as long as there is no lamp post on the corner of the sidewalk kinda thing). This would, at least theoretically, allow the vehicle to move at right angles, or any angles as it passed through the intersection.

Is it still your opinion that this can't be accomplished? I'm running right out to measure the streets to find out if they can be maneuvered without the extra hardware/software to algorithmically steer around tight streets anyway. Perhaps they are 31' wide (not likely, but it's worth a look). If they are, what would the steering sequence be? (I'm not an experienced trucker, but I'd like to leave instructions for the operator to follow during parades.)

Thanks for the responses thus far. Keep trying. I'm hoping if there's a method based on maneuverability, some programmer in CR4 will put it on a PLC chart (or similar system) so we can incorporate it into the steering system.

Mark

Hello MarkTheHandyman:

as I said I have worked it out with scale model sheets of paper, and there is no way the size of trailer you mention is going round that junction. can you shorten it by just over 4', or make it narrower?

Hi, Babybear!

The rear end of the trailer can be shortened by exactly 4'-0" through closing it up, since it is the rear extension of the lower side of the trailer's back side, is closable, and would just have to be re-opened around the bend.

What do you think would be the smallest intersection around which the trailer could travel without shortening/articulation; and is there a preference, in your opinion, of wheel arrangement/suspension in which you would choose to place the wheels in order to make the turn in the simplest manner?

Mark

Hello MarkTheHandyman:

I appreciate you getting back to me.

Taking the 4' off allows no slack whatsoever! You may be able to gain a little by having it narrower. Can you do this?

I am assuming the sized you gave were the maximum. And, of course other things you find on junctions are lights, signs, and traffic lights, not to mention shop signs.

Please understand...........I am thinking about this and I am not in the Haulage trade or trailer builder. But, I would have thought that a central axle on the trailer, and maybe a part of your float like an upright stanchion exactly half way along would make driving easier. As you would know that this has to touch the corner wall to allow the truck round the bend. I tried to get as near accurate as possible but, if I was a mm out, that equates to 4" ! I am tearing and cutting on a tray on my lap. I do not have any fancy stuff to use.

But, please remember, I did this with pieces of paper. 1/4" to the 1'. It still leaves you with no clearance unless you can ride the walk way.

If the truck base is very much narrower than the 16' you say is the width. How about giving Father Xmas a seat belt and put some hydraulics on one side to lift the whole float assemble up on one side only. The side on the left, looking from the back if you are turning left. It would make the whole thing narrower and look like Father Xmas is flying?

Can I suggest, you make a mock-up of the overall size, and, with a friend at each corner simply do as I did and try to get round the junction. You only need some 2''x4'' and you can try without guessing? You may look a little silly, but, not half as silly as if you cannot get round the corner when Father Xmas is on board!!

You ask me about a preference of wheel arrangement? I can only think your Father Xmas can afford some real fancy 'do-dad' of a motor, if he is able to specify where the axles go! LOL! The floats we have round here are just dressed up trucks. Yours sounds like two trucks side by side?

Am I right here, that you are making the trailer? I have never seen one with an axle in the middle before.

And, of course, if the whole thing can be made a little smaller the axle does not need to be in the middle but you will need a steering one I think.

Also consider that most streets don't have square corners. I worked with a radius of 25' for the curbs and the float will go with a few inches on the corners and at the break point. It would need 4 wheel steering to make it. That does not allow for the tractor, though. If the radius is there, still a lot of problems to work out. -- JHF

If you've ever watched the big cranes maneuver, they are able to move essentially as though they were floating on water, so it's not a limitation of the wheels (though you do have to look out for wheels projecting past the envelope) or the steering (the last big crane I saw being driven like that had two drivers and I'm guessing a darn high level of skill).

So, if you can get, say 32' clear space between buildings (no lamp posts, no parking meters, no fire hydrants), I think you can do it. I have no idea what algorithm I'd use, though I could probably develop a crude ad hoc one

Wheel steering angles and if there is a set of wheels without steering, it's position WILL affect how the unit turns. -- JHF

Hello MarkTheHandyman:

This is interesting.................are the lines and widths absolute or, is it possible to let either the wheels or the trailer overlap the curbs?

The answer would be perhaps to have two smaller trailers allowing articulation.

I would have said the place for the wheels on the trailer is about half way along its length. Or have steering rear wheels.

Assuming a straight trailer, unless you can 'ride the curb' to make the road effectively wider, or allow part of the trailer to run 'over' the curb 'space'.

Actually, I have just cut a piece of paper to represent the 'square' of the junction, and if the space available is as you have written the dia of the junction is 24'.

But, as I see it you can add the dimensions of the junction, and of another 24' of the road you are leaving, and, also another 24' of the road you are entering........(To get as much dia as possible).............And, excluding the tractor, which is not really part of the equation............there will still be 8' of trailer that will not go round the junction.

To have it steered as a fire engine is, from the back is no good as it is too long, and extra wide.

How many others have just cut it out in paper as a scale model and tried to get it to work,.......like me!

It has to be more narrow or shorter by 4', to get round, and that is leaving hardly any clearance. With this width 16', you would I think need two articulations in the trailer.

Are there any sidewalks? Never have built a float but things to consider are the wheelbase for estability, how many sets of wheel to support the weight and its destribution. the front wheels definitely have to be up front, the second axle 8 to 10 ft. behind and the third axle about 30 and the fourth axle 3-5 ft. away. that would put the overall wheel base length at about 40 - 45 ft. the trailer would have to overlap and be mounted on top of the second axle, approx. 4-6 ft., to cut the lenght of the float and have more steering capabilities.

The width, without making calculations on the turning radius, should not exceed 10 ft. The wider the float, the harder it is to turn.

Good luck on your project!

Hello MarkTheHandyman:

I am going to bed now. Catch you tomorrow.........

Does it have to be rectangular???

Could you put a radius on the rear of the trailer? This would allow the same over all length and provide clearance for turning. Since I do not know the layout of the float could I make a suggestion anyway? The rear area with a radius could serve as a stage for Father Christmas or a Christmas Tree.

Hi, Mechanic, Babybear, and Everyone Helping Out Here [Thank you all.]!

The float is being designed for a cross-cultural steel pan band (actually 3 separate steel pan bands with a layout as shown below: the young band, the seniors' band, and the band for people from 20 to 59, all sharing the one float and utilizing it at different times and during different events) sponsored by a charity that promotes mixed cultural activities. [I play the bass pans in the senior's band.] So in the Santa Claus Parade, we don't have to worry about Santa. He's on his own float at the end of the parade anyway.

But the float will not just be used during one parade. Its main use will be for the parade during Toronto's Carnival celebration, called "Caribbana" held each August throughout the city, and other connected festivals, such as the Samba Parade and the Junior Caribbana Parade, both separate events occurring around the same time. And during the winter and when not being used for parades, it will be covered and used as a band practice and teaching facility. We are hoping to have a park donated for it where people can come and picnic and watch the bands practice during the good weather; and where other steel bands can visit and perform for local audiences from time to time.

I guess I need to get more specific than I thought at first, about the trailer design. Yes, this will be a custom design, built by volunteers at an automobile plant or by a local truck body manufacturer and donated to the charity. Some sketches are included below to help you visualize the finished product.

It is made from an ordinary 50' X 8' trailer whose sides each fold out into a 4' extension to increase the size to 54' X 16' when it is open as a platform for a parade float. Hence, the wheel base is below the central 8' of the trailer width, not at the outside 16' width. Articulation might be possible, although it would have to be accomplished with people standing around the articulated joint. Still, it might be possible.

This is just a sketch of how the float might appear, both opened (top), and closed up for normal transport to a parade site (bottom) before being opened again to full size.

Although the placement of the wheels beneath the central 8' width won't make any difference as to the turn-ability of the float, the rear end opens out just like the sides, and can be closed to eliminate a 4' section of length in a severe case of need, such as a tight turn. However, the sides can't be folded up during a parade, because the full float will be in use, as you will note below. (I appreciate babybear's creativity here...Santa flying...Haw!)

I've just had a look at the layout of the surface of the float, and it could be articulated at about 50% of the way along the trailer portion without interfering too much with the activities going on above (steel band). So the front 35' feet or so could be turned independently of the rear 29' or so (allowing for the inclusion of the radius of the articulation arc in the length of the rear portion for purposes of calculation). Would that be helpful? The following view is of the trailer without the attached tractor, 54' long, 16' wide, and showing an articulation arc centered somewhat forward where you can see the "+" to divide it approximately in half for articulation. The only instruments that might be affected would be the conga drums, which are easily moved to the side if necessary. However, in an articulated vehicle, an overlapping collar would probably allow them to stay in place during turns anyway.

Mark

AH!

NOW I see the problem.

Stu

I looked at your trailer in DesignCad again (see my previous post) but this time with the back and sides four foot sections folded up. It's close to line to line at times in the turn, which I think makes it impractical in actual application with a human tractor driver. This option would possibly work if the trailer was just a little shorter.

With articulation the 54 foot trailer would likely work.

Obviously before I started construction of the trailer, I would get very specific with the model (such as hitch location). Maybe even to the point of mocking it up with a tractor and standard 54 foot trailer in an open parking lot with cones. This would prove it is practical to drive by a human and not literally require computer controlled steering.

Hi, DaveB!

The tractor is not articulated. It is a custom affair, attached to the trailer permanently, and forms a part of it, extending about 10' (or a little less) in front. It is specially built only for this purpose, seats a (hopefully) more-or-less centrally located single driver (possibly two persons), and is very low to the ground by comparison with normal tractors. (A person walking alongside might be at the same level as the driver inside.) The purpose of this design is to have the float be one single unit with one major purpose, and not have to contend with other uses or parking issues, etc., being thought up for the tractor portion. Thus the entire length of the float should be thought of as a very long van. Articulation is, however, possible, at the point I illustrated above.

Mark

Thank you for that clarification. I had thought the tractor attached to the trailer with a ball hitch like most floats. Probably one center articulation like you presented would work but please look at the mechanics of steering and tread path.

When the front wheels steer the unit rotates around a "friction center" I'll call it. If any rigid unit has more than two axles, while you turn the steering wheels these axles must also steer or the tires just scoot. Watch a large multi-axle straight truck. The bogie axles tires either scoot or they must also steer. From reading your posts I see you already know that.

It seems like your trailer problem has three interrelated issues. Will the vehicle physically go around the defined turn, will each articulated section make the turn (if articulation is needed) and which axles are fixed and which steer?

Another thought is that they do make bogie axles that the wheels turn but not steer meaning they follow the ark they are drug thru without steering input.

Mark,

How did this ever drive before you came along?

Stu.

Hello MarkTheHandyman:

I can figure out most of the words you write on your diagram. But not all. How are you going to arrange the First Aid room, as it is partly on the opened side panel?

Any chance of a series of pics or a movie as you go through the stages of the build?

When I looked at your picture my gut feeling was the float size would not physically fit around the turn. I did a 5 minute DesignCad drawing and sure enough when I use drag and rotate mode, the float (even without the tractor) would not go around a turn with this width restriction no matter how the vehicles are steered.

Some possibilities are: wider street, smaller float (preferably shorter), or articulate the float (this would be cool but maybe not so easy).

For physical problems like this I often go to "PaperCad" (paper dolls). It can quickly show the direction (put intended) you want to go so you can then do the problem in a more structured way, such as geometry.

PS. If you put hair and hats on your paper dolls your co-workers will look at you funny.

Mark,

If you 5th wheel it and have a steerable single axle at the rear of the trailer (or a multiaxle bogey, sim. railcar) ( or horsedrawn waggon). Simple does it best. Remember to swing wiiiiiide.

Why will you need axles all along it's length?

Stu.

Assuming that you axles at the extreme rear of the float that can turn at 45 degrees to the centerline and that (depending on how good your driver is), you have 16 inches clearance at all clash points:

It won't make the turn with the dims as provided. You'll need at least 32.5 ft approach and departure widths, instead of 24 ft.

Couple of scenarios for a 24 ft wide street:

For a 16 ft wide float - the max float lenght would be 30 ft approx

For a 8.5 ft wide float - the max float lenght would be 45 ft approx

The STREET is 24ft. How much wider is the light-pole, building line etcetera?

There must be a sidewalk?

Just a thought.

Cheers,

Stu.

Hello Guest:

can you explain where you got the 16" clearance and, I assume you mean the edges of the inner buildings and, edges of the outer-most corner of the truck hitting the assumed 24' road width, as 'clash points'?

No offence intended OK?

Hi Mark,

DaveB's suggestion of float articulation has to be the best way. Use a steel plate over the gap and the whole length will remain usable ( see bendy busses used in most European cities). Why not, if the tractor is custom, remove this from the equation and use a large flat bed truck (European style vehicle where the steering is above the front wheels) + trailer? Remove the cab from the truck and customise that lower down so the driver is unobtrusive.

Best of luck and post the pics of the final result / solution.

Chas

Hello MarkTheHandyman:

the extra details are very useful thanks..........No flying Santa? Rubbish!

You realise you have made things even more difficult now..............with having the Tractor as part of the main structure, it increases the length even more! I was assuming the Tractor was on a ball-hitch.

The ref' I made of articulation half-way-along, could make this vehicle unique. You can design the articulation with just a small gap to allow for the turn. Have the front (Tractor) end 'convex' at the rear. And the front of the rear potion can be 'concave'. You may need to design extra filler pieces for the truck sides when closed though as, when the trailer is closed for transporting long distances the 'side-boards which lift up as per normal lorry or truck, would will have bits missing to allow for the articulation, you see?

Now the tractor is part of the same trailer I will have to get my pieces of scale model out again and add the length of the tractor.

I have not done so yet, but from my experiments from last night/this morning, it would seem inevitable that a central-ish articulation be included. It complicates things a lot, however, you are getting it built by professionals which should get things right!

Whatever happens I would go to the most crucial junctions (middle of the night may be best when there is no traffic) with some friends and 'walk' the complete size layout made from slotted together 2"x4", to see if the signs, traffic light, fire hydrants and any other obstructions will make an apparently 'wide enough route', narrower, if you see what I mean.

I will be trying it out with scale model (bits of paper) but need to know for certain where the articulation will be exactly. I can work it out as per your sketch but moving the 'joint' will make a difference, though how much I have yet to find out ................................ Now, wheres those scissors and tape? Do I still work to the 24' rule?

Can you get back to me on where the articulation point is best places, and or, where it can be placed to allow the thing to get round the bend?.......Which is where I am going!!!

I am getting some soup ready for my 'dinner' now, see you shortly. Sorry, did not mean to call you 'shortly'!

Mark,

I like the topic and the motivation for it. Since the tightest point going around the corner is when the float is at a 45-degree angle, the float will require the same clearance as a pole of negligible width and a length equal to the length of the float plus twice its width. The corner will not allow this "equivalent" pole to be longer than 24'x2x1.414 = 67.8' (rounding down).

For a 54' long float, its width cannot be greater than (67.8'-54')/2 = 6.7'. If you fix the width at 16', the length of the float cannot be greater than (67.8-32) = 35.8'. For a full-size non-articulated float, the minimum street width is (54+16+16)'/2.828 = 30.5' (rounding up).

If you articulate it, the assumptions which allowed the calculations above no longer are valid. because the shape of either half of the float becomes a rectangle with a semi-circle on one end. The straight pole "equivalent" to either articulated section is closer to length + (2.4)width. Therefore the length of either articulated section cannot be greater than (24'x2x1.414)-(16'x2.4) = 29' (rounded down). This may work with the layout you posted.

The tractor section on the front of the float can be ignored, if its length plus 1/2 its width is less than 8'. On a custom-built unit, I think this can be done with a cab-forward design.

For steering an articulated float, I don't know how to determine the proper axle positions. Two possibilities come to mind. Both have 2 axles under the front section of the articulated float and a fixed axle under the rear. Also, both have the front axle being the driven axle.

1) Front axle steers normally and middle axle steers the opposite direction by an amount somewhere between 50% and 100% of the angle for the front axle. These axles are as close to the ends of the front section as possible. The third (fixed) axle under the rear section is about 2/3 the way back. Its exact location is somewhat dependent on the % of steering allowed for the middle axle. The middle axle steering could be done with a hydraulic master/slave system to have the front axle position control the middle axle. You can use a sliding rear axle like many trailers now have.

2) Front axle steers normally. Middle axle has freedom to self-steer when the pivot point between the two sections of the float is fixed in the straight ahead position (float acts like a very long truck). Middle axle is fixed in straight ahead position when the pivot point between the two sections of the float is free to rotate (float acts like a truck with trailer). Middle and rear axles are about 2/3 the way back in each section of the float (sliding axle rails mentioned above could be used for both of these). Switching from articulated to straight would be by a driver-operated pin that would drop into a hole or slot to lock the two sections into a straight line when the sections came into alignment while the pin was actuated. When the pin becomes engaged, a sensor would then disengage the lock on the middle axle so it can self-steer. The reverse approach would switch it from straight to articulating.

Note that option 2 above would allow the float to be parked in a normal manner and ensure that the two sections were aligned so the "sides" could be closed tightly.

I think that any articulation of the float into more than one section, with a continuous floor adds one other problem. The discussion above was for motion around the "Y" axis only. But as the float is driven on roads or streets there will be some forces around the "X" and "Z" axes also. Do you eliminate these forces, or allow for motion on these two axes at the point of articulation?

1) If you allow for motion on the "X" and "Z" axes, the articulation point would have to be a ball centered at the floor line. Each section's floor would have a hinge line angling inwards (towards the other end of the section) at about a 50-degree angle from the articulation point. The floor of each section would extend in a curved arc around the articulation point outwards by about a 30-degree angle. The two sections of the float would have their hinged floor portions overlap with bearings and guides to kep the overlapping portions parallel to each other. Any band equipment mounted across hinged sections can have only three mounting points (tripod). Any band equipment mounted across a sliding section would have to include a ball roller under one (or two) leg(s). This assumes a maximum of 45-degree turn between the two sections, with a minimum overlap of 15-degrees.

2) Or, you can build the float so there is no motion permitted in either the "X" or "Z" axes. This would require that the suspension be built with hydraulic equalizers so all axles can move up or down and angle so the "vertical" load on each wheel is kept approximately uniform. The hinge point between the two float sections would be a vertical pivot only. This eliminates the need for any hinging discussed above and allows for the float to be leveled on uneven terrain (within the limits of travel for the hydraulics). The floor sections would still need to extend outwards by about 30-degrees as mentioned above. Any band equipment mounted across a sliding section would have to include a ball roller under one (or two) leg(s).

My choice would be to use the second of each pair of options I mentioned above. I hope that this rather wordy reply gives you some practical help.

--JMM

Hello jmueller:

you make some good points and understandable as well, well done.

I said earlier that the extra length, (including the tractor) would make it more difficult. Forgetting that the tractor was 8' wide only. So as I said last night, the tractor is not part of the equation. I also said earlier today or last night that the two articulated parts can be built so they pivot round each others axis so the front will be convex, while the rear trailer will be concave at the joint. Sorry but it is the only way I can explain it.

I tried a 'solid' trailer yesterday and it just would not go round. Today I pivoted it at a central point, so each trailer is 27' and it goes round, but, there is very little scope for error. That is allowing for the full use of the 24' road width as mentioned at the start of the string.

I would go for, as I mentioned before, a two axle front trailer with the axle as near the pivot as possible and free steering, which you mentioned. This will make the ride smoother on bends for people who are on or near the pivot. The back end does not need steering, but, as with all articulated lorries, its wheels will scuff. It may not need it but it will make things easy on very tight corners and also improve the ride if the back wheels are steered. This can be done manually but the ideal would be to have auto steer from the cab. Though I am not sure how. Personally I probably would not bother with the back wheel steering.

As I said last night, I think the over-lap or parralel split pivot will make this a one of a kind and may be copied by other float makers?

He has not answered any remarks today. Perhaps he is out re-measuring the junction?

Hi, babybear!

Venkat and I are hoping that other float makers will copy this design after it is completed. You may have noticed that not only is there a good 42' of useful float surface, but there is also a complete first aid room and WC, both with lavatory sinks, and a complete sound booth with a refigerator for storing lunches and cold drinks. The sound booth operates a mic system throughout the trailer and speakers along its perimeter. With a finely tuned mic system, recordings can be made into CDs.

What is not shown is the idea that the entire open trailer has a fitted tent with air lock entrances up a stair on both sides. This system is applied when the float is parked in its (donated) park with power and sewage services attached so that it can be used as a teaching facility and practice platform in bad weather. The heater/air conditioning units on the roof will modify the internal temperature, and the air locks will double as mud rooms and cloak rooms.

In good weather, the sides can be left open and the band practices held during times when the public can picnic in the park and watch the practices. (When I lived in Boston, the Boston Pops orchestra had its pre-performance rehearsals open to the public...and it still does. They were even more enjoyable because the conductor--it was Arthur Fiedler at that time--really 'practiced' the orchestra; frequently stopping pieces to correct the flow or instrumental voices during the rehearsals. It was a great learning experience about both the dynamics of the orchestra and the piece being played.)

Being open to the public during rehearsals will also attract people of all ages who want to learn to play pan instruments, and that will eventually augment all three bands with a flow of new players.

I even had a thought that the CCAH (the charity for whom this will be built) might put a snack booth (a little extra income, and they could sell the CDs as well), a stand of bleachers and a kiddy playground in the park. And that the park might have room for guest bands to set up and play for concerts, etc.

Mark

Hello again Mark,

The fact that others may 'copy' your design I mentioned last night. Especially the idea of a fixed sound booth, loo, and first-aid.

Actually it is little more than a huge (can't spell gigentic!) 10 ton truck? That is to say the 'payload' in people and instruments?

Didn't see you last night and, imagined you and half a dozen (whats that in metric LOL!.......friends walking your full sized model round the junction you mentioned originally! Still might be the easiest way to see any disasters before they happen?

These responses are very rewarding. Thanks, everybody. The discussion is evolving to a point where a decision can soon be made I think of how to manage this. In the meantime,

Hi, jmueller and Baby bear!

The thought put into your responses is refreshing. I was not certain, however JJM, about where you are placing the Z axis. In each case, the latter half of the articulated portion is free to move about the center point of the rotation to a limited extent, and that point of rotation is located on the forward half. In the case of an arc of connection, an overlapping collar would eliminate any "pinching" potential during a turn caused by the sliding of parts over each other.

However, your response made me think that if the trailer were to be articluated in two places rather than one, the float might be able to "snake" around turns. For example, any two of the following three arcs could be incorporated into the design without radically disturbing the instruments.

Can you graphically illustrate your two preferred solutions for greater clarity? Here's a 'blank' platform to draw on. I have included two lengths for the tractor, your suggested 8', and my original thought about 10', because I find it difficult to imagine where I would put both an engine and an operating cockpit in only 8':

(This is a jpg image, and can be manipulated in any paint program.)

Mark

Hello Mark,

with ref' to the trailer only, as the tracker can be eliminated for purposes of design as it will go round anyway

I made the joint in the trailer at exactly half-way-27'. But, I feel a foot on the front trailer and a foot less from the back trailer could be accommodated.

A company making Military trailers and pulling full sized tanks, used to drive its local roads which were not far from me. These drivers have a different 'language' and way of looking at things that the everyday driver! The factory had been in the middle of fields, but, over the years builds and roads were laid with seemingly no thought for the huge lumps of steel driving out of this factory. They sometimes had to make a detour and drive through a road which was narrower than 'main' roads and was just a long arc. But they managed it by hardly moving at all, and anything like mirrors folded in flat to the sides. What they also had was 6' or longer steel bars with little round plastic nobs at the end. The bars could swivel on a 'uni' joint and were slightly wider than the load. They had about 4 pairs of these along the sides and, knew, if the first guides went through, then the rest of the trailer would as well.

This may be useful in your case. They were set just a couple of inches wider than the load and it made unnecessarily close contact by the tractor or trailer to posts, and buildings not needed as the little balls on the end of these poles would touch first doing no damage and, allowing slight alteration of the steering. It worked sort of like an invisible space surrounding the load, if you like. This is where a 'drivers mate' comes in handy! Though on these trailers they had about 4!

Did you see the piece I sent to jmueller last night?

I am finding it difficult to read the measurements you have down the side of your trailer. When I enlarge the screen they cannot be read at all, least not by me.

Do you think the two trailers at 27' with overlap will work? As I say you can shift the joint with preferably the front trailer being longer by at most about 29', though to make it easier to maneuver I would have the from 1' longer than the back.

Mark,

I am working away from home and don't have the time right now to work with your jpg image. I appreciate the interaction you have had with everybody on this thread. It helps to keep the ideas flowing and to smooth out some potential problems.

Regarding the X, Y, and Z axes I mentioned: I chose the typical graph convention of looking at the trailer from the side and having the Y axis be vertical (you steer around this axis). The X axis runs the length of the float and the Z axis runs cross-ways. Assume for simplicity, that the float has three axles--one very close to the front, one under the front half but very close to the pivot point around which it articulates, and one towards the rear of the back half. As the float's front axle starts to climb or descend a slope that is straight ahead, if all axles remain on the ground, there must be rotation around the Z axis. [This means that the front and rear halves of the float are in different planes that intersect along a line.] If you are going from a level surface to a slope, but doing so at an angle (instead of straight ahead), there is rotation around both the X and Z axes. [This means that the front and rear halves of the float are in different planes that only intersect at a single point.]

If you want to keep the intersection of the front and rear halves safe for being on and having instruments on, you need a way for the floor to allow this motion in all three axes. Or, you need a way for the suspension of the float to make up the difference between the ground and the float as the float travels across changes in slope, so the floors of both halves of the float remain in the same plane. A couple weeks ago, I saw a heavy-hauling trailer deliver a very long 80-ton tank to our work site. Under the trailer were 11 pairs of half-axles, each with 4 tires. (Including the tires on the tractor, this made it a 106-wheeler!) Each half-axle had a hydraulic cylinder so it could move up or down and still carry its portion of the load over uneven road surfaces. All but two pairs of half-axles (at the rear of the trailer) were with pivots so they could self-steer when the trailer was going around curves. These two features allowed the trailer to go around corners with virtually no scooting or dragging of tires, and allowed it to travel over non-flat and non-level road surfaces without bending the trailer or overloading an axle.

If you build the float so it can't pivot on the X or Z axes, then you either must provide a suspension which keeps the two sections of the floor in a single plane while the tires follow the changing contour of the road surface, or you must allow for it to bend and ultimately break. If you allow pivoting on the X and Z axes, then you must design the intersection of the two floor halves so there is an intermediate plane which connects to each trailer floor with two intersecting straight lines and a sliding joint within this intermediate plane to allow for the intended Y axis motion.

I understand your meaning of the rear half having a concave front while the front half has a convex one. This is based on how you draw the meeting of their two floors. However, as the float turns around a corner, the front half occupies the same amount of space in front of the rear half as would be occupied if the rear were convex and the front concave. In other words, to get around the corner, each half requires the same space, regardless of how the floor sections slide or pivot.

Since the float is traveling at a relatively slow speed, the power requirements will be smaller and you do not need a lot of space for the engine. It could probably be put behind the driver under the front end of the float floor. The transmission and drive axles, etc., could even be eliminated by the use of a hydraulic pump on the engine and hydaulic motors on the wheels. This approach would allow the operator's cab to be relatively small. Visibility for clearances on turns, etc. would require outboard mirrors and possibly even require cameras and monitors.

Your measurement of the wider streets on the parade route certainly makes clearances at the corner(s) much less of a problem.

I hope these additions help you in visualizing the problems I believe you will need to overcome. --John Mueller

Hi, jmueller!

The pendulum axles are a great idea for moving large loads that may have to go over sizable bumps where spilling the load would be a disaster of great proportions. The nastiest obstacle along a parade route with players aboard would probably be a 'speed bump' series in the roadway. But as parade routes are usually along major roadways where speed bumps have not been installed, that isn't an issue.

The problem with the pendulum axle carriages I have seen is the inordinate amount of metal taking up space around the wheels. As far as independent position steering is concerned, I envision a servo mechanism around the axles connection to the underside of the flatbed with a computer control from the driver's console and perhaps a manual over-ride for those unusual moments.

At the articulation points, there would have to be

• No instruments or standing musicians.
• A stationary overlap plate connected to the front part of the swivel.
• A flexible under-lap plate (your idea of being able to transition the bumps in the road) connected to the swinging portion of the articulation.
• An articulated joint arm (both ends) on the underside of the platform running from the center of the articulation arc to a central point outside the arc on the swinging portion.
• Articulation limiters between the two articulated parts at both sides on the front part and in the center of the swinging part.
• A pin from the center limiter on the swinging part with a receiver on the front part for locking the platform in a straight configuration, also controlled from the driver's console and possibly automatically withdrawn as the steering wheel is turned and replaced as the steering wheel hits a straight direction.

Mark

Hello Mark again.

Just to say jmueller has put a lot of work into this, and I appreciate and understand about half! No........I can see stuff, wheels and what they should do but do not know the technical way to describe them. Bwire help somewhat also......

So, thats maybe three tickets with at least one coming from the UK and Europe (me)!

Perhaps, if you are going to have one, you can put an organ and the player of it on the overlap?

There are several manufactures of transporters; we have Scheuerle Tranporters in the shipyard where I work. Although designed primarily for very heavy loads, these transporters link, with an experienced operator of course, can maneuver into just about any area of their footprint. They can be leased, from Mamoet (worldwide and in the Toronto area I believe) for example, but tend to be very expensive.

Food for thought.

Hi, mareng!

Nice. I really admire the development of the "pendulum axles". The articulation styling of those trailers is not going to get this trailer through the intersection, as they are hitched together for articulation; otherwise they can turn when linked as a single unit in the same manner as this parade float might have to do in each articulated section.

The machinery the company in this link uses for its suspension/turning/linking effects is very large and cumbersome for a parade float, even if it can be adapted to arc-shaped articulation. I'm hoping to achieve independent wheel steering with small hydraulic units on swivels with a 'uni-directional' locking device as described by jmueller above.

However, I like the linked company's ability to build close to the ground, which, if it were possible to do for the parade float, might be an advantage (although I can't see how that could be done any lower than a standard trailer deck due to the size of the wheels and requirement for a flat deck above --maybe with smaller wheels). And they really do look expensive! (Fortunately for the CCAH, the cost of what ever is eventually designed and built will be borne by donations!)

Thanks for the link.

Mark

Hello Mark,

just another thought. The flat deck very low machines are often remote controlled. And with all those wheels the maintenance costs would be horrific, both in money and time. Keep it simple with a minimum of axles.

Now you realise it must be articulated you can build a unique looking band-stand, and I would have thought any Local Council would be queuing up to have this in their parks! It is like two grand-stands put together, and portable. Perhaps you can work together with a council or Authority and advertise their name on the side in exchange for them building and providing parking facilities?

Can you tell me what the rectangular things are which the arc you have drarn goes through please?

Here's your solution...requires a highly-skilled driver, a welded pindle-hitch and everything on the trailer nailed down.

What about using a trailer with tarp style sides instead? This would still allow for some sliding floor and roof elements but not limit you to the 16 foot width. Roll up the sides, extend the floor and roof to suit the particular parade route, and enjoy the rest of your day.

Hello Mark,

I have not used Paint much and am not familiar with it so cannot draw with it.

However, as I have said I would choose the centre trailer split as I know it works.

Just one other thing..........I see you have drawn three arcs. I presume the front one is possibly for the tractor hitch? But, have you tried to maneuver back and forth with more than one split trailer? It aint easy! I would still stick to the simple design of yours with the fixed tractor. And one other split in the trailer.

By the way, you have used arcs very much wider than the trailer. Is there a reason for this? Not being an expert I do not know, but I would have thought an arc based on the 16' width would be ideal? Of course I may be showing my ignorance here, and the arc as you have drawn it may work better?

Been doing some more thinking!...........I have not tried this out but, having the over-lapping floor, may mean you could have the two halves of the trailers further apart, allowing for a 'joint motion' of more than 90°.......is that a degree sign as in geometry? Or temperature?

Hi Mark,

I think I think this task is doable.

1. The tractor needs a few points of articulation enabled by incorporating a "sliding fifth wheel assy" allowing the tractor to turn perpendicular or -5° to the van.

2. The van needs a point of articulation dead center or just forward of the center axle with use of a fifth wheel single axle dolly enabling (converter gear) the front half to turn perpendicular to the rear section. A tag (lift able) axle should be mounted to the rear of the front van section for support.

3. The rear axles should be configured as a spread axle set 6'-8' with rear most axle as far back as possible allowing the tire to remain in the envelope.

4. So we have 7 axles; a steer axle, a drive axle (not a tandem set), a tag axle, a (converter gear) dolly axle and a spread axle set. The spread axle set and the dolly should also be independently lift able. Using single wheels rather than duals would allow ease of maneuvering.

These axle configurations will get it round the bend. I'll leave the art of figuring the figures to the higher CR4 thinkers .

Hello Mark,

hope all is well with you?

I am writing with ref' to your post 34 to jmueller and me.

I am getting really exited about this whole thing now! Like a kid with a new toy.......(that I really like, but can't have!).

About possible adding another articulation point; ........with one split it will be possible to reverse if needed. With two, it will be very difficult. you could however have one or both split/s 'lock' in the straight forward position. This would help in parking etc.

The only trucks etc, that I know of which have several trailers are the 'road-trains' in Australia and they cannot reverse.

I know something about wheels but, not enough to give any firm advice.

All I will say is you do not need any 'fancy' wheel arrangement, and you will probably need a pretty solid deck, to prevent people falling over. These people will be playing ALL the time even through all the difficult corners you may have to drive through? Well, I know it may sound a little extreme.......(what isn't about this planned build?) but, it may be an idea to have waste high supports perhaps with leather belts for the standing players? There is level differences, pot-holes, road drains, and when and if the trailer has to mount the curb (footpath) it could be hard to continue playing while trying not to fall over? Just a thought.

Have you had any other thoughts about the trailer? Or discussions with the builders?

About possible adding another articulation point; ........with one split it will be possible to reverse if needed. With two, it will be very difficult. you could however have one or both split/s 'lock' in the straight forward position. This would help in parking etc.

The only trucks etc, that I know of which have several trailers are the 'road-trains' in Australia and they cannot reverse.

There are many multiple trailer rigs that can back-up and around corners accurately. You may see them hauling grain or pneumatic tanks in a "B" Train configuration in the USA. I remember driving a shorter unit 123' and being able to turn inside of the turning radius of a single 53' trailer rig going forward. Backing requires a simple modification allowing either locking the fifth wheel plate or in-cab independent manipulation of the trailer air braking system (or manual unhook second trailer air), imagine using steering brakes

Hello bwire:

Hope you are OK?

I did not realise that they could be reversed so easily as a single 'artic'. I had thought, and may have put it in my last post, can't recall, that is would be an advantage to have a fixed union .......if there was more than one articulation that is.

Not being a driver for many years now, I have lost the vnanacular........the 'fifth wheel' is what? You mention about locking the fifth wheel?

Did the rig you were driving have a fixed articulation point, or is it possible to reverse with several trailers, having none locked? I could just reverse my small trailer van, so it has to take some skill to reverse/manoeuvre a multi trailer rig?

No insult intended bwire, OK?

Hi, babybear!

The concensus to date is that the parade float should be articulated in either one or two places. I'm certain that bwire will update you on the "fifth wheel", which is not a wheel at all. Locking the articulation points as the trailer is moving either straight forward or straight back is a very helpful solution as well.

We'll post the final decision/design for this thread when it's finished. Keep it alive until then.

Thanks to you and to all the great responses, especially JMueller, Bwire, yourself, and TVP42/saca03142, for whom I have the good news that the narrowest streets in the Santa Claus parade route will be 32' wide from curb to curb.

Mark

Hello Mark,

thanks for the post to all etc. As you may have seen the 'fifth wheel' question I have posted to bwire. It was 'up there' (in my head when I was driving but, has floated away on the ether now!

The 32' Santa Claud Parade streets will be a doddle to get round Almost do a three-point-turn!

Is there going to be a site dedicated to this float and/or Parade. It would be nice to just log-on and veiw the build as it happens, if that was possible of caus........see, santa claus.......of caus?. Oh never mind it was a silly joke anyway!

If you are going to have it ready for Xmas (this year) you will have to get your 'Parade float skates' on?

Sorry, I have forgotten if you told us......is the Parade in Santa Monica? (Not a joke, I just cannot recall the original post, and cannot see it while writing this).

Please give me the date of this parade. I'm flying in just to see this thing actually make it around the corner!

Hello Bricktop:

that sounds a great idea! And after out help I think Mark should pay for all our tickets! Yeah!

Take care

Hi, Bricktop!

Riiiiiggghhhhtt! I'll see ya there!

Ok, here's the scoop about when the parade will be.

The original design has been done (by me). Now Venkat will carry on with the technical drawings.

Next, I have been co-opted by the CCAH charity to find a builder/donator for the float. I am seriously considering either a truck body builder or a trade union to do the work. As far as which trade union, I shall be approaching the Canadian Auto Workers at Ford, which has a huge plant in Oakville...the town CCAH is located within. I'll also approach the resident union at Bombardier to see whether they might be interested in building it.

After a builder has been found, it will have to be built and equipped. I'm going to look for a sponsor to pay big bucks to support the steel band groups on an annual basis in return for advertising on the float (notice the A.S.A. bottle pictured on the float?). Hopefully I can attract an analgesic company such as Tylenol, Bayer, Ibuprofen, Advil, or some other corporate group to make the CCAH float one of its charitable efforts. Because I think a good name for the "pans of CCAH" would be "Panacea"; and analgesics are a the closest thing (other than alcohol) we have to a panacea for 'what ails you'.

Next, the float needs a home. I posted an earlier blog about that.

Finally, the float needs it own new instruments and sound system. This might be accomplished by cash donations or by some large music company doing a donation in kind.

I think we're looking at MAYBE next year's Santa Claus parade. In Oakville Ontario Canada.

The idea to keep a photographic record of its being built is GREAT. I'll look into a volunteer photo group that wants to make a donation of coverage of the project.

Thanks,

Mark

Sorry to come in so late, but there are ideas in my head that need venting.

If the tractor is custom made, What if it is in the range of 25 to 27 feet long, with a short wheelbase, and steep steering angle. This would form the front half of your articulated float. All of the ideas posted for the articulation would be applied to the back half as before.

As for the steerable trailer axles. Oshkosh Truck supplies steerable drive axels to Pierce, for long fire engines. They are steered hydraulically from the driver's steering wheel. These axels should be available in non drive axels also. Rough terrain fork lifts, such as Lull, Pettibone, or JLG, also use hydraulically steered front and rear drive axels.

On a show that I saw on giant moving projects, they use wheel sets that are low to the ground, and attach to steel beams. they attach as many wheel sets as needed to support the load. they are tied together to allow them to drive themselves, and steer together. Try searching house movers, and look at their equipment. Good luck, and send pictures.

Beyond this, have you ever seen the trams that are used at Disney World? One tractor pulls about five trailers, filled with passengers. They can drive around obstacles, and each trailer follows in the footprint of the trailer ahead of it. Sort of like a motorized snake. The trams are getting old by now, maybe WDW would send you a few older trailers to play with.

Hello bob c:

how are you?

At first I thought it would be harder steering etc with more articulations. But, reading what you have said it could be a good idea. Because the truck and platform could also be arranged in a semi-circle, for audiences on one side only such as would watch a band-stand, and maybe at concerts?

Bet we still will not get any free ticket though! LOL! I can't wait to see more of this project. It would be nice and great from a sponsors point of view, to have a video-cam shooting work and sponsors as they turn up to look at how it is going. And the video could also drum up more sponsor by taking to potential factories etc. Sorry about the pun on "drum up", I had not realised until after I was reading through checking for spelling mysteakes!

Take care........

Hi, babybear!

Just gotta say that I really appreciate your ability to think outside the bowl (as it says in my family's 'spoof' coat of arms, below "Versare Ex Sinum").

The semi-circular arrangement for concerts is a very nifty idea (although having the bands play in a 'straight line' configuration is perfectly fine at performance time. But the thing needs to be articulated anyway... Makes me think that a double articulation could be the way to go. But I'm leaving that up to Venkat. I think he's monitoring these conversations.

Mark

Hello Mark,

Bit taken aback there with your saying "your ability to think outside the bowl". I am just being me.

In that semi circular shaped arrangement it would allow you to have a proper little stage, well, not so little really, with a full stage cover with 'stars and moon' on the inside, and, also allow for lighting, coloured lights etc. And maybe a shaped extra piece of 'stage' to fit in the semi-circle?

Just a thought that all.

It would be nice to have exactly what you have in mind. But, when it comes to the frills like I mention here, in the real world you have to cut your suit to suit your pocket I suppose?

Thank you, and please keep in touch about the video thing as it is assembled. As I have said, sorry cannot recall to whom, the filming would also go a long way towards getting your story out there and also having the really all important sponsors on film at the build, and, a copy of the build and or sponsors you already have by then can be shown to other future sponsors? It might be useful to 'sell' (tell) the story of what you are trying to achieve to the local TV. You will get publicity and who knows you might have to build a whole fleet of these 'bandwogans'.

By the way, I cannot recall it now but I know I liked the sound of the name that you mentioned. Sorry I can't remember it. Oh, I know, Panacia. Not sure on the spelling there.

Takecare..........I will have to start charging for my advice from now on. ......What is half of nothing in percentage terms?! LOL!

This whole thing has brought me out of my depression, thank you for having the foresight and vision to put this together. I am glad you said this may be happening the Xmas after next. I was wondering how you were going to get your truck, stage, and instruments made, and people trained and rehearsed by December 2008!

Your parade tickets should arrive soon. My free pair were sent by Fed Ex the next day. I'm sure yours will be there soon.

Hello bob c:

Oh I see, so you get preferential treatment then? I bet you even got 'First Class'! How do you spell 'preforencial'? Lets have a round of applause for the 'Spell Checker'!

It is a great project though! And sooooooooooooo BIG !

Oh look! Airline tickets for us also.

Hello bob c:

I am angree now! It was my idea and I haven't got my tickets yet!

Take care my friend........

You're coordinator of the mail buoy sentry detail?

I believe you have been wronged.You need to organize a boycott of the parade turn.With time on your side, you should be able to have that intersection EMPTY. That will fix them. If I need to destroy my comp tickets, let me know. CR4 must stand firm against this oppression!

If parades are outlawed, only outlaws will have parades!

Hello bob c:

If parades are outlawed, only outlaws will have parades!

Thats brilliant. I have always wanted to be an outlaw! Can I ride my Harley I haven't got?

And is CR4 standing firm? I thought I felt a tremor just now?

Hello MarkTheHandyman,

I know it is well past the date of the first use of this trailer and bands, but, did you ever get it made and do you have any pics? Or videos?

Take care,

Hi, babybear!

Great to hear from you. No. Nothing has transpired with regard to the plans/building as yet. New requests for funding and participation are due to go out shortly. The chap in India who volunteered to do the working drawings disappeared without explanation.

Mark

Hi Mark,

Likewise, good to hear from you my friend!Bit of a bummer to hear of the float though. Working drawings are the way to start of course but, for someone to promise and then not do his job kinda sucks!I will keep in touch. Oh, I thought you had the funding and it was due to be built this Xmas gone? Obviously the funding and more to the point, the cost has a lot to do with what you can get done through the 'friend network'? I am not saying it will, but do you have a vlog or blog for this? Just another way of publicising, you know.

John

How did the parade work out?

As you were well aware, ALL of CR4 boycotted the parade. This caused strife on the city. The city council members decided to change the parade from a winter parade in the cold weather, to a warmer location. The shift was made to a remote town in Uruguay. The streets were wider, and there were no curbs or buildings to interfere with the turns. The parade was not well received though. Only one float showed up, and the towns folk were needed to guide protect the float so there was no one to watch the parade. The parade sponsors are trying to work out corporate sponsorship for it next year. If you travel to Uruguay next year, look for the Tidy Bo2wl Toilet Bowl holiday parade.

Sounds like a much better host.... Country of the year and all. Except for the "warmer" notion. :-)