My life with Python trikes Mk1 , Mk1.5 , Mk2 ?

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Hi all

Well it is exciting as this could be the first International Zombie meet ?

4 people from 3 different countries.

However we will need to put it on the back burner for this year IMHO , lets hope next year is better for all of us ?

Does anyone know that area ? is there anything of interest around there ?

I have done the Louwman museum and the aircraft museum at Lelystad both would make a good day out for a group of amateur Zombie engineers ?

Paul
Both places I have never been. As you like trains, then Utrecht the train museum is also an option.
Best near Eindhoven has the war museum and there is an other meseum where a cycle lane goes straight trough the museum.
I forgot witch museum but I can look for it.
 
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So how to build a Flevo rear pivot Python uno 1

After much arguing constructive dialog between the :-
North and we build it with what we have and the
South ' it ain't any good unless the lathe has been deployed '

This is the result:-



Grey card represents frame 1.5" sq 1.5mm wall :-
lower frame disappears to the left to the rear wheels
upper frame has upper seat mount above pivot area and to left upper rear seat mount and front end pivot bracket on the angle to the right

as you can see the piece that controls the distance between the 2 parts of the frame is the rubber elastomer also as it is the farthest part of the joint away from the frame open ends so it need doing first

lower part of elastomer has a M10 threaded rod it is screwed into a M10 hex coupler which does not quite fill the 1.5" tubing , so I have welded the coupler to an off cut of 6mm plate that will be welded to the inside floor of the tubing through 2 x 6mm holes , this will allow the elastomer to screw in from the top and not have any hardware for this joint under the frame.

the upper frame tube will have a M10 i/d anti crush tube welded in and a M10 bolt will screw into the top of the elastomer screw in maybe with a bit of locking compound ?

The female rod end will be mounted on a 4" M12 bolt [ horizontal in this picture ] and inside the tube welded to a pair of 3mm plates plug welded from the outside through 4 x 6mm holes / plate
The vertical M12 bolt will pass through a M12 i/d crush tube and be held under the upper frame by a lock-nut , I expect the female rod end will be free to pivot a little however it is captive and has no where to go ?



The positioning of the parts is an almost exact copy of the Flevo bike method except on the Flevo trike the frame tubes are no parallel ?

What I am not comfortable with is the axis for the rod end pivot does not pass through the vertical centre of the elastomer ?
Does that mean the elastomer is compromised in some way ?

of course the rod end could be in the vertical centre of the elastomer , it would just be very messy looking ...

answers on a postcard please..

Paul
 
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Does the elastomer not have bonded on threads both ends? From your description it would seem not and you plan to screw a bolt directly into the elastomer. If that's the case I'd expect the first corner to rip it out. It needs a bonded plate with threads both ends, something like this.
 
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Popshot

Stop being so macho :whistle:, that is a Male/Male ?

I have a Male/Female :D



So all is well with the world ...

Well it is now the soft southern Jessie pointed out that it is a threaded top hat section you can see on this side , and NOT as I thought the end of the threaded post in the other end DOH [ where do these people come from ! ]



Lost in the wilderness Paul
 
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What I am not comfortable with is the axis for the rod end pivot does not pass through the vertical centre of the elastomer ?
Does that mean the elastomer is compromised in some way ?

of course the rod end could be in the vertical centre of the elastomer , it would just be very messy looking ...

answers on a postcard please..
I don't think there will be any serious issues or dire consequences Paul (well, not for us watching, at least). ;)

The man you stole the idea from reported that his bolted together beast had done 4k miles and the elastomer was still good.
He has his elastomer and rose-joint arranged at opposite ends of the double-decker parallel keel sections so the amount of "lean" articulation at the sharp end is much bigger than the resultant twisting/shearing of the elastomer down at the blunt end. The elastomers are meant to cope with reasonable levels of bend/twist and shear forces.
The ones I bought are 154Kg compressive load and 53Kg shear. What did you get?
 
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I don't think there will be any serious issues or dire consequences Paul (well, not for us watching, at least). ;)

The man you stole the idea from reported that his bolted together beast had done 4k miles and the elastomer was still good.
yes thinking about it if the rod end is below the base of the elastomer the full height can be used for it to lean ? giving more lean than if the pivot was higher ?

The ones I bought are 154Kg compressive load and 53Kg shear. What did you get?
The black ones ?
 
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yes thinking about it if the rod end is below the base of the elastomer the full height can be used for it to lean ? giving more lean than if the pivot was higher ?



The black ones ?
Ahhh yes... black ones, they are the very bestest of the best. No possible issues then. Enjoy. :)
 
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Ahhh yes... black ones, they are the very bestest of the best. No possible issues then. Enjoy. :)
Mine say Model 5045MF28-60
Diameter 50
Height 45
V:M10 thread size
L 28mm thread length
Max load 84.kg
Deflection 4.0mm




Looks like I have 60' shore , what ever that means ?

maybe I need either 2 or more max Load ?

Paul
 
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I looked up shore A on Google and got this answer:
"The Shore A Hardness Scale measures the hardness of flexible mold rubbers that range in hardness from very soft and flexible, to medium and somewhat flexible, to hard with almost no flexibility at all. Semi-rigid plastics can also be measured on the high end of the Shore A Scale.

The Shore D Hardness Scale measures the hardness of hard rubbers, semi-rigid plastics and hard plastics.

How Do You Physically Measure A Material's Hardness?
The different Shore Hardness scales measure the resistance of a material to indentation. A ‘Shore Hardness' gauge (looks like a round tire pressure gauge) has a needle on a spring protruding from one end. The needle is placed against the rubber or plastic and pressure is applied.
Once the gauge is pressed firmly against the material and the needle has penetrated as far as it can go, the measurement needle will indicate the corresponding hardness measurement."

So I cannot see how that table of info you have tells us how bendy or what weights the elastomer can withstand Paul.
Try one at first, see how bendy it is.
 
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So I cannot see how that table of info you have tells us how bendy or what weights the elastomer can withstand Paul.
Try one at first, see how bendy it is.
Well the writing at the top of the post telling you the weights etc came on an invoice I printed off ?

Looking up the model number gives the first row on the second table [ under the headings ] and 84 [ kg ] is under shore 60' A ?

Specs I have seem to indicate shore 55' B , so what's the difference ? who knows....

Paul
 
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Ok it should look like this ?



Lower portion in red is outline of lower frame tube [ bolts at either end are just supports ]
You can see the bracket and M10 hex coupler on the left , the elastomer will screw into that - this will be welded inside the tube
Next are 2 x 3mm plates that have a 4" x M12 bolt through them - this will be welded inside the tube.

Upper portion in blue is outline of upper frame tube
On the left will be a anti-crush tube for a M10 bolt/threaded rod that will screw into the top of the elastomer
On the right is some M12 threaded rod that will also run in a anti-crush tube [ however bigger than M12 as we need some wiggle room left to right and side to side ]

Between red and blue are the elastomer and the M12 female rod end bearing.

I have welded the horizontal M12 bolt to one of the spacer plates and made a spacer tube for between the right hand end plate and the rod end bearing trying not to restrict the motion of the rod end and the frame ?

I need to determine the correct distance between the 2 plates so :-
a) the elastomer/rod end distance is as close as possible to the Flevo Trike
b) there is sufficient thread to the right of the rod end bearing to allow a few mm of movement when positioning it
c) avoid if possible having to cut thread in the non-threaded portion of the bolt
[ apparent someone from ' down south ' does not recommend that to ' past the time ' on a sunny afternoon (n)]

Paul
 
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Hi Paul
A 50 x 45mm rubber bush can handle about 220kg.
It's a trial and error situation, and if no good, estimate a replacement based on the 60' value.
 
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Hi Paul
A 50 x 45mm rubber bush can handle about 220kg.
It's a trial and error situation, and if no good, estimate a replacement based on the 60' value.
When you say 220kg under what circumstances ?
compression ?
bending ?
other ?

Paul
 
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need a measurement ?

centre of elastomer to centre of vertical rod end bearing.

So blew Flevo Trike drawing up till tubing was 1.5" and erased all unwanted bit's



Centre to centre is 10 cm , I measured the parts I had and though the closest I could get them was 9 cm so that looks like I have the space for the hardware at least.

Paul
 
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Good shout Paul, it looks right doesn't it?
 
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Ok so lower frame member welded up ?



This is underneath one plate welded to end of square tubing next welds along are a ring going around the tube welding the 4 faces of the rear plate that holds the 4" x M12 bolt seen on the left.
other 2 welds hold plate that M10 hex coupler is welded to.

Left side with rod end bearing and spacer on :-



need to find length of 1 washer and 1 locknut then trim threaded portion down.



You can clearly see the M10 threaded hex coupler , I could not screw elastomer in as it was much to hot !

next some wooded trimmed and hammered into open rear end to allow rear axle from Mule to clamp around it.

upper frame tube next.

Paul
 
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Smashing Stuff Paul.
It is coming on a treat. Lots of articulation from that ball-joint. :)
 
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Smashing Stuff Paul.
It is coming on a treat. Lots of articulation from that ball-joint. :)
Would not do it this way again ! much to much inaccurate flap disc work , I think the bolt is a few degrees out looking from above luckily the closer to the plate the rod end is the less deviation !

Next up screw a off cut of M12 into the rod end and drill a m12 hole in some plywood and bolt it to the rod end , with a M10 in the elastomer hole I can mark that on the plywood and when drilled and confirmed ok I have a template for the upper frame tube.

Paul
 
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Would not do it this way again ! much to much inaccurate flap disc work , I think the bolt is a few degrees out looking from above luckily the closer to the plate the rod end is the less deviation !

Next up screw a off cut of M12 into the rod end and drill a m12 hole in some plywood and bolt it to the rod end , with a M10 in the elastomer hole I can mark that on the plywood and when drilled and confirmed ok I have a template for the upper frame tube.

Paul
The bolt being out a degree or 2 shouldn't matter; there is more than enough "range" in the ball-joint.
Positively zooming along; so you are. :)
 
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Ok so this has not gone to plan (n)😢



As can be seen the rod end bearing only has a single lock nut between it and the wood template [ representing the lower face of the upper tube ] where as it needs 2 IMHO

Also the template is bent up towards the rod end indicating even this won't work in steel !

So thinking maybe elastomer needs a 6mm plate underneath the upper frame tube this raising the nose of the tube over the rod end bearing ?


This appears to have only 1 nut , and a slimmed down nut as well , probably for the same reason as that elastomer seems to have less height than mine ?

regards Paul
 
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