A Configurable Jib

[Paul F]

The objective of this project is a lightweight, configurable jib. This jib breaks down into 4' sections and packs into 2 small bags, plus tripod and weights.

It can be set up as a 16' high, 12' high, or 8' high jib by removing sections. The 8' configuration does not require guy wires.

For the 16' jib, 35lbs of counterweight is needed (25lb in picture). The weights are on a slide that allow the balance to be fine tuned for perfect balance and then locked of with a hand screw.

There are two control boxes. On the top one, the three silver switches are power for motors and camera, auto iris enable, and remote focus enable. The two red switches are record and index. Also on the box is a small joystick. On the left is the cable from the camera head and on the right is a cable going to the second box (who knew 4 pin XLR cables only come with two wires? Thus the messy cable).

On the bottom of the top box are two XLRs for microphone input back to the camera, for remote microphones.

The second box has iris control on the left and focus control on the right. I'm going to change the focus to have the white space for marking focus points and add an index pointer on the box.

A 13" monitor with 1280 x 800 resolution and HDMI from the AF100. Yes, it is glossy. But I prefer that for focusing.

The monitor and the motors are powered by the battery that is taped to the monitor arm. Cable management, battery mount, and controller mount haven't been sorted out yet.

The guy-wire arm can be moved along the jib to adjust for different length jibs. A guy-wire set is required for the 16' and 12' jib.

I used a surveyors tripod for strength and for the flat head and solid mount. Level is achieved by adjusting the legs. 1" bearings and tight tolerances make for nice smooth movements. The tripod mount also slides along the jib arm to be set for each jib configuration.

4' sections are connected with a hand-screw.

Three guy-wires are required at the top of the head to keep this lightweight jib steady.

The head.

The tilt motor and gears.

The pan motor and gears.

I'm very satisfied with the jib. I have complaints about the pan and tilt motors, which I have discussed on Jeremy's thread. http://www.dvxuser.com/V6/showthread.php?248253-My-Custom-Built-Camera-Crane/page3

 

[Jeremy_Sawatzky]

this is great!

your horizontal panning axle, how is that suspended and what types of bearings did you use? I see some servocity parts but whats in that vertical cylinder? you seem to have the same setup for the vertical tilting.

My setup will have both motors on the actual head and will be powered by batteries. so my horizontal panning hub gear will be mounted to the crane itself.

I like your mounting configuration at the end of the crane (to hold the head) far better than mine. i think i will be redesigning mine.

video of the head in motion if you please???

 

[Paul F]

It might need a sketch to explain, but let's try it with words. Starting from the bottom of the shaft, under the gear is the black plate of the head. Between that black plate and the gear is a shaft hub (from servocity) to which both the black plate and the gear are bolted with screws; 4 for the plate, 2 for the gear. The hub clamps to the shaft. Only friction holds the hub to the shaft. It will not come off. It is very strong. As a backup, there is supposed to be a second, smaller hub that uses a set screw in case the main hub loosens for some reason. But it is not installed. The bearings are 1/4" ball bearings that have a very overrated load capacity. I don't recall what they can handle, but it is much more than what is on there. The shaft and bearing holes are made to very tight tolerances so there is no movement of the bearings or shafts.

Then the shaft goes through a hole in the silver plate and through the cylinder. At the top of the cylinder is another one of the hubs. This hub has a shoulder that contacts a bearing at the top of the cylinder. That makes the shaft float on the bearing. There is a second bearing at the bottom of the cylinder. The cylinder provides a way to separate the bearings so that two bearings can have some distance between them and provide some rigidity for the shaft. The weight of the head is resting on the top bearing. For added security, there is a second smaller hub with set screw that is clamped to the shaft in case the hub resting on the bearing gives way for some reason.

One thing that is missing, is the guy-wire used to keep the head level. I use the wire rather than a solid link. The head is balanced such that a guy is needed to pull the head level with a lot of force. This keeps the head steady and level as the jib tilts up/down

It's almost the same on the tilt, but I don't have the backup hubs, because there is no weight pulling the shaft out.

The slot in the tilt plate where the shaft attaches, is used to adjust the center of gravity of the camera, to balance the tilt motor load. I'll try to post a video of the head in motion; maybe Sunday.

Motors on the head; good, I'd like to see it.

 

[Paul F]

I should mention I found the main jib parts in a junk yard. The clamps, hexagon tubing, and the slider were all junk. It looks like these are used in a hospital to rig fixtures for people in traction. The hex tubing is really lightweight, but strong. I wasn't looking to make a jib. But when I saw this material at the junk yard, the idea for a jib just came to me.

 

[Jeremy_Sawatzky]

yeaa.... i spent about $200 on aluminum hehe