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PostPosted: Mon Apr 22, 2013 4:56 pm 
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Joined: Sun Dec 30, 2012 4:38 pm
Posts: 192
Location: Graz, Austria
Hello,

Last year I have designed a device to be able to easily move and rotate my Haflinger platform. My idea is to use the original four axle boltholes in the platform for mounting it on the device, as I suppose this would be the most universal solution. The rear "axle" can be mounted in two positions according to SWB and LWB. The axis of rotation should go through the platform's center of gravity, so it can be rotated without effort. I am thinking about the possibility to add removable counterweights to the device, so that an excentricity of the COG, caused e.g. by additional parts like front nose etc., can be balanced.

What do you think? Any suggestions for improvements?
In the CAD model, the platform is, of course, much simplified.

Image

Image

Kind regards,
Constantin


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PostPosted: Mon Apr 22, 2013 5:02 pm 
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Joined: Sun Dec 30, 2012 4:07 pm
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Location: W Sussex, UK
Hi Constantin,

That looks really good, and I would be interested in buying one / making one / contributing to the design costs etc.

My only comment would be to make it suitable for those Haflingers with a welded front end (as it would appear that you have), as not all of us are able to remove it even if we wanted to!

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Julian B
W Sussex, UK

| '62 Early Series I SWB | '72 Series II LWB |
| '56 Citroën Traction Avant |


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PostPosted: Mon Apr 22, 2013 7:39 pm 
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Location: Graz, Austria
Hi Julian,

the vertical pillars are high enough to allow the platform to rotate 360 degrees, also with the front nose fitted. I agree that the system should work for all kinds of platforms.
I must say that I haven't made up any proper drawings yet, so the production is not possible right away. Also, I still have to experimentally detect the COG of a real platform to get the design right.


Kind regards,
Constantin


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PostPosted: Wed Apr 24, 2013 1:18 am 
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Joined: Sun Dec 30, 2012 3:12 pm
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Location: Canada
Hi Constantin,
I sure could have used your rotisserie design when I restored "Murphy". Maybe you'll have the design complete by the time I start my next project. As a suggestion you could make the vertical pillars with adjustable height to allow for changes in COG as the platform work progresses from panel removal through replacement and addition of other components. Counterweights may be simpler for COG compensation but several weights of varying mass would be needed and a means of attaching them would need to be designed.
Cheers,
Steve


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PostPosted: Wed Apr 24, 2013 6:58 am 
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Location: Lewes, East Sussex - UK
Would be far simpler to just make a straight bar between the two vertical ones instead of the off set in the above drawing. Then as suggested you could have short arms on to which you could add counter weights - if they were tubing you could use "weight lifting" weights.

John

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Haflinger 703AP LWB 1973 - (Once owned by Lady Sutherland & Sons.) Now called "Lurch" !

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PostPosted: Wed Apr 24, 2013 3:59 pm 
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Location: Graz, Austria
Steve, I agree with your proposal. Adjustable vertial pillars of the rotating part of the device would be nice, but I also believe that this would lead to a more complicated design. Also, the stiffness of the rotating part might suffer, compared to a completely welded single part. Do you have a precise proposal for an adjustable design?

John, I agree that a straight connection of the two rotating tubes would be a lot simpler. However you have to consider that the center of gravity of the platform is also its volumetric COG. Allowing a large excentricity of the platform's COG from the rotational axis would also mean, that there is much more space needed for a full rotation. Hence, the height of the main vertical pillars would have to be increased and more space in the workshop is required.

Kind regards,
Constantin


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PostPosted: Wed Apr 24, 2013 6:55 pm 
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Location: Canada
Hi Constantin,
A fairly simple design for adjustable vertical bars might consist of two sections of concentric square or round structural tubing of reasonably close fit to each other. These tubes would have multiple cross drilled holes at approximately 25mm spacing for insertion of a hardened locking hitch pin. This would be something similar to the height adjustment system on some brands of axle stands. The mechanism would be sufficiently rigid, very strong and considerably adjustable.
Cheers,
Steve


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PostPosted: Wed Apr 24, 2013 7:33 pm 
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Location: Lewes, East Sussex - UK
You could make a few other things adjustable. The two main vertical legs with the same idea as Steve has suggested. That would allow a straight tube from one arm to the other, even with an uneven COG you could adjust the height to give you a good working height.

A similar Tube sliding on a tube with a hole and pin system for the bracket used to differentiate between the SWB and LWB variation would mean you would not have to undo Nuts and blot, just slide it to the new position and put an Pin in with an R clip for safety.

The counter weights could be short tube which take Weight lifting weights which would be held in place in a similar way with a pin and R clip to ensure they did not fall off when you rotated things.

Just trying to make it simpler to make. :)

John

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Haflinger 703AP LWB 1973 - (Once owned by Lady Sutherland & Sons.) Now called "Lurch" !

Have you hit the "DONATE" button at the bottom of the page after reading this post? Many thanks if you have!!


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