The construction is with little metal brackets that I made the main "tilt" frame with L-brackets and the rest to make the cage with a block of wood for the main bottom support.
This frame was placed inside the "pan" frame which hangs off the original camera platform on the crane.
For controls, I've attached springs to the top of the tilt so the camera points skyward naturally, then ran a cable down to the control end of the crane for the operator and attached that to the bottom of the platform so the Op can counter the springs by pulling back on the cable to tilt down.
I made a PVC/wood handle on top of the crane which rotates, then attached a cable on either end each of which run down a side of the crane and pull on the top left and top right respectively to make the pan work... so currently the left hand drives the crane and operates the pan, while the left hand operates the tilt. It pans ~120 degrees and tilts ~100 degrees. The cables are run through silicone tubing and that through eye hooks for mounting to the camera.
It’s awesome! Can you throw up some more detailed pics when you get a chance?
(I understand from what you are saying how it’s constructed, but I always like to see how the various mechanics and fabrication and mounting and the whole lot are gone about.)
EDIT: Ahh I see now from the video. All wood frame. Sweet!
I use angle iron for the "fork" and pipe inside of pipe for the roation, then pipe for the boom because I haven't found a junk futon frame for the box steel (so I can go flat against flat
with bearings and clevis pins).
I haven't tried a control head, looks tricky.
I’m doing another table top dolly today myself.
Last edited by Buddy Greenfield; 08-09-2010 at 12:53 AM.
I can probably mark up this one in photoshop... we built it sitting on the floor of the hardware store grabbing parts as we went, so I didn't take notes or pix while we were making it.
This pic really shows everything that it's comprised of - I'm not sure what other pictures would get other than different angles, but I can arrange that... perhaps some shots of the tilt section more dramatically pivoted so you could see it better. I really don't have a good way to capture the construction though photographically (better than what I've got above)... do you have specific pictures you'd like to have me get?
Well, itís not important (I more or less understand what is happening with it, but thanks though),
Iím just always curious to see and learn more and other ways and designs and how things mechanically operate and what can be commonly used to fabricate those mechanical functions and how.
Quite a bit. I'm a tinkerer. The hinge points are just washers on bolts with nuts on either side to hold the bits that are hinged. Nuts, washers on bolts for spacers/standoffs. and random metal brackets for the structure, there was a whole wall of them at the hardware store.
OOH... and if you have an old bike to tear into, you can make a chain driven one with gears to turn the bits up front (long chain).. but that could be attached to a motor (which could be at the end, past the arm to stop the chain from binding... then wired to a stepper motor from Axman's
It’s funny you mention the bike parts, as I have been toying around with bike gears lately, but not sure what I’ll make just yet.
I was looking around in my junk buckets and noticed something that made me laugh at the possibly to be fabricated into an inexpensive lightweight semi-precision head assembly for smaller cameras. (The wheel from an office chair!)
It rotates 360 two ways on bearings and has a shaft that can easily accept a clip or pin to secure it.
(Two could be used to fashion the assembly for heavier/larger cameras.)
I think with a little doing it could be controlled by bicycle brake cable and that type of spring mechanism.
If your location looks like the set of Sanford and Son, and you’re not filming a remake
-you could be Indie!
Last edited by Buddy Greenfield; 08-09-2010 at 03:06 PM.
If you put a cross arm on the pin of the caster, then an arm out front on top which has a cable through a fixed (or sprung) pulley that pulls forward on the bottom of the assembly (with springs to pull it back), cable through silicone tubing (bike brake cables - but longer if you need them to be)... these could operate as a control system.
See, that kind of mechanical operation (Control via spring and cable) is something I have never experimented with. Sometimes Iíll try stuff 100 ways and be pulling my hair out, then a week later Iíll see a picture or an object where that same operation is employed, and just scream at how easy it actually is.
Here is my 1st pan/tilt caster jib head -basic cage- mock up:
Itís rough, but I think I can refine the cage to just two inexpensive pieces, a platform and the frame.
And here are my 1st loose design diagrams for it:
IF you can make sense of them, would you say Iím on the right track for the spring mechanism for pan and tilt?
I donít understand yet in my design (or any, but I'm trying to from yours) how the two springs set-ups might interact in various positions. I mean, if you pan, it would change the alignment of the tilt springs (it would twist them).
I know itís hard to say, but mechanically (in general) do you think the tilt springs might just be expected to stretch and move on the attachment ďringĒ (eye bolts) when twisted (panned), or am I not getting or seeing the use or need of some kind of like pulley swivel attachments in the mix?
It looks like it'll work, loading from one direction and pulling against that spring force should work for both axes and simplify the control structure at the far end. It will, however, require that a hand be on both controls at all times, which may not be a problem for you.
Complex movements (i.e. Jib Low and left, head tilted up and right, moving smoothly to Jib High and right, head tilted down and left) are like dancing... the more complex the movement, the more practice you need, and the less natural the controls, the more difficult the choreography to learn.