Adaptable dolly

[Carlos_E._Martinez]

Last week I found a very interesting tripod support that allows an unusual rail to move it.

It starts with a basic 3-point tripod support, where you bolt three 4-skate wheels sets. Nothing unusual about two of them, except that they roll freely around the support points.

But the third set adds a short extension arm, providing free movement both on the support and on the wheel set.

All this allows using a simple rubber hose, like 30mm diameter, to be used as a rail. You extend it in a U-shape on the floor, and then the wheels and the short arm adjust themselves to the way the hose has taken.

Even if it's in Portuguese, have a look:

http://www.dmsvideo.com.br/travelling_mangueira.htm

Selling price is rather high, so I am investigating ways to DIY it.

The hose is sealed at both ends, and it's probably filled with dry sand. But a rubber hose is much easier to transport than two long PVC tubes, so you can fill in and fill out the sand after using the hose.

The key is how to move the wheel sets on the support and on the arm.

 

[bilgami]

its a cool site. id love to build a rail dolly where i can still use my bogen spreader dolly with out having to take it off and on all the time to switch back and fouth between the 2 differ kinds of dollies.

 

[Carlos_E._Martinez]

So do you have any suggestion on how to swing the 4-wheel pieces and the extension arm?

It's some kind of ball-rolling, but I don't know how you can fix one from the inside and the outside.

 

[bilgami]

No i dont. i want to somehow keep the dolly have now and maybe come up with some way to add the angle bar with wheels for the pvc dolly. maybe weld some sort of "U" shaped metal that snaps around the dolly that holds the angle bar that holds the wheels for the pvc dolly.

 

[puredrifting]

Hi Carlmart:

I could be mistaken but I am pretty sure that is either the Losmandy Spider Dolly or a foreign bootlegged version of it.

I own the Losmandy PortaJib Traveler and I have been contemplating buying the matching Spider Dolly. They sell it in 3 and 4 wheel versions, you can read all about it at http://www.portajib.com/spider_dolly.htm

It's not cheap but I have rented them, it's a very well engineered system. The tubing will give you issues, everyone thinks you can just used any old rubber tubing but you can't. In order to get the right sidewall strength, compound and rolling resistance, they use custom designed rubber tubing made to their specs. The dolly rolls very smoothly on it around any curves.

This probably doesn't help you in your quest to build this design yourself but I did want to let you know that the Portugese/Brazilian site above is probably just adapted the Losmandy design and knocked it off.

Best of luck,

Dan

 

[bilgami]

thanks i had no idea they did that. but that looks like a really well made dolly. i dont need anything that fancy. i shoot mainly weddings, i just wanted something incase i do a outdoor wedding.

 

[Carlos_E._Martinez]

I could be mistaken but I am pretty sure that is either the Losmandy Spider Dolly or a foreign bootlegged version of it.

I own the Losmandy PortaJib Traveler and I have been contemplating buying the matching Spider Dolly. They sell it in 3 and 4 wheel versions, you can read all about it at http://www.portajib.com/spider_dolly.htm

Thanks for the tip, Dan. The spider dolly certainly looks as the inspiration for the local dolly. In this case only one leg has the extension arm.

It's not cheap but I have rented them, it's a very well engineered system.

Believe it or not, the local version is more expensive than the original. So I don't see any reason why should I buy it.

The tubing will give you issues, everyone thinks you can just used any old rubber tubing but you can't. In order to get the right sidewall strength, compound and rolling resistance, they use custom designed rubber tubing made to their specs. The dolly rolls very smoothly on it around any curves.

Apparently the tubing has to be filled with sand or water, as a friend of mine told me. To that effect they add some "corks" to insert on the tube ends. Strength may also be a problem if you jump on the dolly, but I don't think a tripod with a video camera will strain things that much on the hoses.

This probably doesn't help you in your quest to build this design yourself but I did want to let you know that the Portugese/Brazilian site above is probably just adapted the Losmandy design and knocked it off.

Quite the opposite, Dan. Your comments are very valuable.

My concern is mainly on how to build the movement mechanics, both for the wheel sets and the extension arm.