Homebuilt jib - comments are welcome

Bob Hart · January 5th, 2006, 09:47 PM

One other item you might consider is to make the arm bearing a tension load, (should be the upper one), adjustable for shorter length.

I made a 15ft crane a long time ago and incorporated adjustment to enable the rig to pull the camera upward a few degrees as it approached the ground so that upward tilt by the operator to stay on the shot is not needed or is reduced.

This arrangement only works from the crane being halfway up where the arms are in the level position. Any higher and the camera begins to tilt upward again off the shot. With careful rehearsal, that tendency can be helpful if the subject is approaching from about 50 metres and halts close to the camera.

The other difference with this rig was that I made the pivot centre of the main arm about 15mm higher than the end pivots, same for the upper arm. This conferred a self leveling tendency which can be adjusted high or low by adding small trim weights to the countermass bin.

This makes it easier for the crane operator to find a common start or end point over several takes as the crane automatically goes there.

Neither of these options are in commercial rigs as far as I know. There may be good reasons why from an engineering standpoint. It was a bit intimidating for the cameraman to have the seat and camera move forward at height. Closer to the ground it was okay.

Eniola Akintoye · January 8th, 2006, 03:03 AM

Gang,
Is anyone making something like this for commercial sales?
I will definitely be interested.

January 5th, 2006, 09:47 PM	#16
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	One other item you might consider is to make the arm bearing a tension load, (should be the upper one), adjustable for shorter length. I made a 15ft crane a long time ago and incorporated adjustment to enable the rig to pull the camera upward a few degrees as it approached the ground so that upward tilt by the operator to stay on the shot is not needed or is reduced. This arrangement only works from the crane being halfway up where the arms are in the level position. Any higher and the camera begins to tilt upward again off the shot. With careful rehearsal, that tendency can be helpful if the subject is approaching from about 50 metres and halts close to the camera. The other difference with this rig was that I made the pivot centre of the main arm about 15mm higher than the end pivots, same for the upper arm. This conferred a self leveling tendency which can be adjusted high or low by adding small trim weights to the countermass bin. This makes it easier for the crane operator to find a common start or end point over several takes as the crane automatically goes there. Neither of these options are in commercial rigs as far as I know. There may be good reasons why from an engineering standpoint. It was a bit intimidating for the cameraman to have the seat and camera move forward at height. Closer to the ground it was okay.

January 8th, 2006, 03:03 AM	#17
Eniola Akintoye Major Player Join Date: Jul 2005 Location: Duluth GA Posts: 238	Gang, Is anyone making something like this for commercial sales? I will definitely be interested.