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Pedal-powered kid-car: Nils-auto

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moto-klasika Avatar
moto-klasika Zoran R. Pualic
Bern, Bern, Switzerland   CHE
In reply to # 20300 by stegla Zoran,
I would like you to continue this thread here on Cyclecartclub.com.
It's no big deal if you are forced to take a break from the off-topic forum for a few days.
Steve
=====================================
Hello Steve,
Thank you on practical and rational advice!
I will not close my topic, but for now I am not in a great mood to post too much. Maybe later...
--- ---
Now, I had two issues to solve before starting final desing of Nils-auto:

1) transmission:

1.a) should I have two-step transmission (from pedals to jack-shaft and than by chain to left rear wheel – single wheel power) or just one (from pedals with single sprocket, by chain to left rear wheel) - with 6 speed derailleur;

1.b) if I would have two-step transmission, should I have first step using hanging pedals with levers to crank-jack-shaft or system with sprockets and chain;
1.c) adjustable distance from pedals to back-rest is (a few positions for different size of the same kid, or maybe other kids too) - easiest way is with hanging-pedals and push-pull levers at the first step, but it is double with chain too);
1.d) I had idea for “simple” revers on the right rear wheel, but now it looks to me as problematic – anyway, I could try it and if it didn't work, I could simply remove right chain;

2) seating ergonomic:

2.a) seat should be horisontal, with back-rest at angle of 100-115° to it?
2.b) legs should be almost stretched in furthest position on pedals, and in that position almost horisontal?
2.c) kids of 3 year are 95 cm tall (average, and +- 5 cm in extremes) and kids of 8-9 years are 130 cm tall (average, and +- 10 cm in extremes!);
2.d) it is important to know for any “size of kids”, how much they need from back-rest to furthest position of pedals; could I suppose that it is 55-60% of height? in Steve's kid-car, distance from back-rest to pedals (I suppose middle position) is 67 cm (44 cm + 23 cm) for tall daughter... I suppose that in Nils-auto, it would be the biggest distance for the last years of use;
2.e) I think that I have to plan shortest distance around 50 cm? that isn't big difference, and could be covered by moving pedals only, or seat only, or in combination; fine adjustments could be made by various thickness of foam pillows?

As was said, it is questionable if Nils (or any other kid) should use pedal-car trough so many years, but if it has either bad transmission and entire mechanics, or bad ergonomic position - he shouldn't use it at all, except in period of auto pulled by parents (and hopefully by grandparents!). Of course, aesthetic is important too.

Ciao, until next time!
Zoran




Zoran R. Pualić
(mostly living in Bern, Swiss & happy in my Belgrade, Serbia)



Edited 1 time(s). Last edit at 2016-12-10 09:07 AM by moto-klasika.

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Bathgate, West Lothian, UK   GBR
Hi Zoran

Extremely excited to see you starting your build!

I think 20" wheels size is perfect. There are some quality BMX tyres that go up to 2.4" wide, but give you minimum rolling resistance, extremely thought and hard earing and come with a choice of wall colour if you want to integrate this in your design. However black wide rims and spokes with fat tyres would take care of the look of the kids cart.

If you look at BERN pedal carts they might give you an idea of seat sizing, gearing etc. for a specific age group.

With regards to clutch (one way) bearings I am planning to integrate them in my design as a freewheel differential due to low cost and simplicity. I was never a fun of one wheel drive as if you apply sufficient force while going uphill the cart seem to move in the direction of the drive wheel (I suppose you can call it power steering :-)

Good luck with your build and post as many pictures as possible.

Kind regards Vitaliy

carmelmike Avatar
carmelmike Michael Stevenson
Carmel, CA, USA   USA
1925 CycleKart French "Delage"
1933 CycleKart Italian "Whitney Straight Maserati"
1934 CycleKart American "Brannon Special"
1934 CycleKart French "Bugatti Type 59"    & more
Hello, Zoran!

I love the Ganz-Standard!! Peter would have, too, I'm sure. And the video of the gas-powered Moskovich is great! Cute little cars. Russian? I like that they have lever-drive, as some of our larger pedal cars do. It's a much more pleasant feel to pedal a lever-drive car than a circular pedalling motion, I think.

I look forward to seeing your project move forward!

Best,
Mike

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Thrush Michael Sutton
Redditch, Worcestershire, UK   GBR
Zoran, before I built the Jeep for my grandson I bought him a pedal go cart in Jeep livery.
The drive is by chain, with a pedal back brake and you can pedal it backwards, I'm not sure how it works but I think it may be of use to you. The make is Berg. Have a look and see what you think.

Regards. Mick

Bathgate, West Lothian, UK   GBR
Sorry Zoran now that I have read Mick's post it is the same make BERG I was referring to in my earlier post.

Kind regards Vitaliy

moto-klasika Avatar
moto-klasika Zoran R. Pualic
Bern, Bern, Switzerland   CHE
Hello to all friendly persons, interested in my (just started) work on Nils-auto!

As I will try to avoid new temporarily ban, I will comment a few of your posts in the same letter!
--- ---
Vitaliy,
Thank you on nice words and good advices! No problem with mentioning BERG pedal-go karts on two places, better that than not to have any reaction at all!

As I am working on tinny budget, with modest tool in small "workshop" in basement, I will use components that I could obtain, including those that I already bought. If everything go well, and testing was successful (I will offer it for a drive for neighbor's 3-year son), I could replace some components with those of better quality and look. (first to check how present should be accepted by Nils's parents, he would like it for sure)... Nice, wider wheels and colored tyres would be great. I have time to check if they could be bought here in Bern or ordered on internet. As everything here is extremely expensive, maybe ordering from USA or China could be more economical...

On my full-size pedal-powered quadricycle, I had crank-pedals and power transmitted on both rear wheels, with derailleur system on both sides. With free-wheeling, there would be quasi-differential action and possibility of synchronized speed-changes, with some practice... The same I could make on Nils-auto, but need another kid-bike as donor, or separate bought components. I am not sure if that is worth of possible benefits? With small kid-power and lower speed and low weight, it shouldn't be much difference with power on one or two wheels, on ordinary smooth asphalt pavement? For off-road driving and on slippery (wet) asphalt - two-wheel power should be better. I could prepare everything for both variants, just to replace right single-speed rear wheel with one with the same derailleur as the left already has.
--- ---
Mike,
I am glad that you follow my modest thread/topic about modest pedal-powered kid-car! Stevenson's kid-cars are magnificent, but I wonted something designed and built by myself (old dream from childhood). To be honest, probably that I shouldn't have enough patience and precision to built such masterpieces, as are Stevenson's and a few built here.

I am sure that Pete would like Josef Ganz's work and maybe him as person with interesting and turbulent life!

Pedal-powered Moskwitch, as my son had and one motorised are Russian products (origins from USSR era). Ugly car but a lot of fun in either variant!

I just wanted to ask: what system is more practical (easier to use and more energy efficient): one with hanging (or standing) pedals and levers to crank-shaft (final or jack-shaft) or one with circular movement of feet (bicycle-style pedals with sprocket and chain). For me, without any experience in either for some kind of velomobile – it seems more natural to use legs in push-pull, horisontal movements? From old Russian magazines about pedal-autos, I noticed that they used the first system, but with combination with cables and chains... Maybe to use push-pull levers for primary transmission (from pedals to jack-shaft under seat) and then bicycle transmission with 6-speed derailleur system?

I will check all that on some sketches (hand-made, do not know to use computer design) and maybe with wooden-stick mock-up before final solution.
--- ---
Mick,
Thank you on interest for my project, in spite that it is modest and shall looks rude comparing to your and other presented here... I found BERG web-site and even dealer in the centre of Bern! Should go there to see it in real and maybe to take some dimensions for model proper for kids form 3 up to 8 (14) years old. I remember that I saw one in Belgrade before came here, and when ask if it is for adults too (looks quite big), arrogant seller said: could be, but what fooll would drive something like this and why? I would, if had money – they are quite expensive!

Abut system that you explained, they write at web-site:
Hub: BFR Hub stands for Brake, Forward and Reverse; this hub allows the driver to pedal forward, coast with the pedals remaining static, pedal back slightly to use the coaster brake to stop, once stopped pedal backwards to go in reverse!

I have to check that and see if it is possible to order just that component. Do not have money for entire go-kart, and if I had – I would buy it and maybe built some cute body on it...

When I was searching for kid-bikes, I saw one with 3-speed gear-box in rear hub, with brake that we call “contra”: turning (pressing) pedals in revers just for a little – chain brake rear wheel efficiently! But, later it couldn't turn it in revers. Maybe to check that again. Old, big, single-speed bicycles in old Yugoslavia had such brakes: safe and efficient.
--- ---
Steve,
Not to forget to mention that until now I learned a lot from your excellent work on wonderful kid-auto! Of course, that is more an inspiration, because I would stay bellow that level, but I will steal some ideas and solutions!
--- ---
I will attach some pictures with a few variants of push-pull pedals, mostly with cable-chain combinations. Next time, my idea for revers, that probably shouldn't work, but...

Regards to all,
Zoran




Zoran R. Pualić
(mostly living in Bern, Swiss & happy in my Belgrade, Serbia)



Edited 2 time(s). Last edit at 2016-12-10 08:41 AM by moto-klasika.


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moto-klasika Avatar
moto-klasika Zoran R. Pualic
Bern, Bern, Switzerland   CHE
.. as could be seen on previouslly posted pictures, there are a few variants of pedals: standing (fixed at "floor"winking smiley, or hanging (fixed at "bonnet/hood"winking smiley, or sliding in rails, pulling chains or cables or their combination and – two bicycle's free-wheels (separate or at wheels) or universal sprag-clutches (sprag barrel bearings )... Attached is a pair of pictures with similar system, and of course one with the simplest of pedal-system used for the second Stevenson's kid-cars!
--- ---
About my planed (dreamed?) simple reverse system that probably shouldn't work!
My idea for reverse on kid-cars or any other similar pedal-powered quadricycle using bicycle's elements – are simple (maybe naive, too?):

1. Left side I would use in normal way for forward drive (no need for two-wheel drive with small power and low speeds); in this case with one single front sprocket on pedal-system and 6-speed derailleur system at rear;
2. Right side I would use for revers drive (no need for two-wheel drive with small power and low speeds); in this case with one single front sprocket on pedal-system and one-speed free-wheel system at rear; the right wheel would be turned for 180°, so that free-wheel and sprocket would be inside (left of wheel);
3. Driving forward, left side of transmission would work as on single bicycle, but right side would be free-wheeling, no mater that front sprocket and chain should turning forward;
4. Driving in reverse, everything should be opposite: left side should be free-wheeling, no mater that front sprocket and chain should turning in reverse; right side would act as on single bicycle, but moving entire quadricycle in reverse;
5. The best would be if front sprockets are individual and not connected with mutual crank-pedals, only it would be more complicated to make two systems – one for each side, but that isn't impossible?

New thoughts: described forward-revers system couldn't work if both front sprockets are fixed on the same axle (crank-pedals or junk-axle), except if both front sprockets are of the same size and rear sprockets too... I will try that, but if it isn't possible, I shall simply removed right chain (that activate revers) and make system with just single (right, rear) wheel driving forward. In the first years, parents could push Nils-auto in revers and later young diver could push rear wheels by hands (in leather gloves) - just for a few meters... For bigger, heavier and more serious vehicles - electric revers is the simplest solution and could be made DIY. (for Nils-auto – cordless screwdriver with friction drive on wheel?)

I have to check all that on sketches, but maybe on working models, too. Maybe to test it on my big HPV quadricycle, turning left rear wheel and front sprocket?
Attached is rude sketch of presented system.

Zoran

P.S.: Al presented in this thread/topic is more memo for my work than useful instructions, but could be useful for somebody else as archive of information?




Zoran R. Pualić
(mostly living in Bern, Swiss & happy in my Belgrade, Serbia)


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stegla Stephen G
Guernsey, Channel Islands, UK   GBR
Zoran,

One drawback of the treadle pedals is the space needed under the seat for the throw of the krank 10" or 250mm total. A system using sprag clutches looks interesting?

Don't worry about reverse. The kids use the back wheels like a wheel-chair, using their hands to set off and again for reversing.

I must be near my pub posting limit too!

Steve

carmelmike Avatar
carmelmike Michael Stevenson
Carmel, CA, USA   USA
1925 CycleKart French "Delage"
1933 CycleKart Italian "Whitney Straight Maserati"
1934 CycleKart American "Brannon Special"
1934 CycleKart French "Bugatti Type 59"    & more
Zoran,

I like the swinging-lever drive system, for a couple of reasons. The movement feels better to me, and a person's knees don't rise so much and hit the dashboard, and I've always been curious to try a sort of simple gearing system using sliding connecting rod attachment points on the levers. Closer tot he pivot for more torque at the crank (and a longer foot movement), and further from the crank for less power (and short throw.)

Anyway, just my two cents.

Mike

moto-klasika Avatar
moto-klasika Zoran R. Pualic
Bern, Bern, Switzerland   CHE
Hello Steve and Mike!
(again one my letter on a pair of comments -
to avoid next ban, the last just passed this afternoon)
--- ---
Steve,
You are quite right about reverse! I was curious but probably not any need for complications!
(I would have a lot of them in any way)

Treadle pedals at front part with crank-shaft as middle axle (jack-axle) and rear part using bicycle transmission – looked practical to me, but you are right about available space under seat! Even if I moved crank-shaft axle back of seat, horisontal levers from pedals should go a lot up and down... Back to thinking corner of my room (or my mind).

Nothing strange that almost all of old USSR velo-autos had some combination of cable-chain push-pull systems with two sprag clutches (free-wheel) on jack-axle or at rear wheels... Such systems were used later, from time to time!
--- ---
Mike,
I was think too (but wasn't sure, without experience), that moving feet front-rear is more natural and more efficient way, when seat is law, not as high seating on bicycle... Swinging lever system, or sliding pedals – could be check on sketches, but both should accept lower bonnet/hood which is important for small cars.
--- ---
As I could see, a`la Stevenson's system of hanging swinging pedals, levers and cranked rear axle – has some advantages, beside simplicity: there isn't dead-point because inertia of auto should help there and it is possible to go in reverse? (non-existance of free-wheeling anywhere)... Both of that isn't possible with chain/cable system and sprag-clutches (free wheels on jack-axle or free-wheeling on rear wheels)... Disadvantage: there isn't system for speed-changing, trough dérailleur or something else? Mike's idea for “gear-changing” trough moving position of fixing point on levers could be developed? (Mike, any sketch?)

Still to think about that, during following days...

Ciao, Zoran




Zoran R. Pualić
(mostly living in Bern, Swiss & happy in my Belgrade, Serbia)

chrisenamels Avatar
chrisenamels Silver Member Chris Brown
Llangadog, Carmarthenshire, UK   GBR
Zoran,

My limited experience of a friend's pedal car some 50 years ago is that the cranked axle was the source of most of the difficulty in using it. It always seemed to stop on top dead centre, so getting it going was a pain. The timing of the push stroke was critical, too early and you'd slow down, or even stop. It was fun though, but these memories memories are what prompted me to suggest sprag clutches.

Advantages:
No TDC, easier to get started
Both feet can be used to get started, followed by alternating
No need for accurate timing of the push stroke
Straight axle, simpler to fabricate
Easily adjustable pedal position with pedal module & multiple holes in drive rods
Easily adjustable "gearing" with multiple holes in pedal and sprag clutch levers

Disadvantages:
No braking, separate brake needed
Nothing else I can think of

Chris

carmelmike Avatar
carmelmike Michael Stevenson
Carmel, CA, USA   USA
1925 CycleKart French "Delage"
1933 CycleKart Italian "Whitney Straight Maserati"
1934 CycleKart American "Brannon Special"
1934 CycleKart French "Bugatti Type 59"    & more
Chris' comments reminded me of one of the major downfalls of the axle-crank-type: They seem even more prone to dead-centering than a rotating-pedal version. Kind of annoying, actually. Kids work around it, but adults aren't usually so patient...

Mike

moto-klasika Avatar
moto-klasika Zoran R. Pualic
Bern, Bern, Switzerland   CHE
Hello Chris,
Thank you on your memories and suggestions! Only memories that I have about pedal-cars was from very early childhood when I lived with grandparents in Bosnia. With my grandmother I often visited general store in centre of their small town, where was one metal pedal car on the second floor. As manager knew my grandmother very well, he let me seat in that pedal-car so my grandmother have a lot of time to go around "surfing" trough shelves and buying something! There was a place for my teddy-bear beside me. My grandfather, teacher in elementary school, promised me to buy that pedal-car when he become a “millionaire”, buying lottery tickets every week. Never happened! Later I bought shown ugly Moskwitch pedal-car for my son... Without floor under, he used feet-power for reverse, but sometimes managed to go reverse using pedals... Of course, playing with grandmother's sewing machine was practical experience in using big pedal and one lever and one crank - but big wheel serve as flywheel too?
--- ---
As I said, I will check a few variants to find the best, do not having too much possibilities for longer and complicated experiments - but, finished vehicle must be practical and easy to operate, comfortable and cute, too. (easy to build!)
--- ---
Mike, front push-pull pedals of whatever type (hanging, sliding...) and free-wheels (sprag clutches) at rear sound as the best combination?

Ciao, Zoran




Zoran R. Pualić
(mostly living in Bern, Swiss & happy in my Belgrade, Serbia)



Edited 1 time(s). Last edit at 2016-12-13 10:42 AM by moto-klasika.

stegla Stephen G
Guernsey, Channel Islands, UK   GBR
Zoran,

Back-pedaling gives effective braking. Look at the video again and at the end (1:04) Zak locks the back wheel.

Girls seem to better than boys at timing the pedal strokes! But they all soon get the hang of it.



Steve

moto-klasika Avatar
moto-klasika Zoran R. Pualic
Bern, Bern, Switzerland   CHE
Hello Steve,
Interesting example of using pedals for braking! I think that it is possible only if is used "a'la Stevenson" method of pedaling: hanging pedals, levers and crankshaft rear axle? All the system is ridge - no sprag-clutches, no chains and bicycle-type free-wheeling, or slipping belts and so on?

When I was looking for kid-bike, I saw one with 3-speeds in-hub gear-box and "contra-brake": turning circulating pedals just a little backwards - there is quite good braking...
As I will try to use bicycle's brakes on quadricycle, I think that now that issue is solved? Front wheels could be braked by hand-levers, two on one side or one on each side of "pilot-style" steering wheel and long lever for rear brakes, serving as hand-brake too...

On my quadricycle I had tow hand-levers on each side of steering handles, so with some practice I could synchronize all four wheel braking. Shall see that in practice after more serious testing. Now, it is too cold (bellow freezing temperature) to finish last details: tuning of derailleur systems, one at each side...

Now, I remember: when pulling quadricycle in reverse to move it around, wheels pulled chains and they revolve crank-pedals in revers. That isn't any big issue for revolving pedals, but could be for sliding push-pull pedals with free-wheeling at jack axle just behind rear seat! I tried that on kid-bike in basement and result is the same: pedals were turning backwards when pull bike in revers, but of course revolving pedals in revers do not have any influence on movement of bike.
So - pushing Nils-auto in revers shouldn't be possible at all - sliding pedals should stop that after moving just a little?

Just cold-day and colder night thoughts! In basement is cold too!

Zoran

P.S. (added): Stevenon's and similar kid-cars have power just at one wheel and another is free-wheeling on axle in either direction? No fix position of both wheels just as for go-karts? Or I am wrong?




Zoran R. Pualić
(mostly living in Bern, Swiss & happy in my Belgrade, Serbia)



Edited 1 time(s). Last edit at 2016-12-16 04:11 PM by moto-klasika.


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