Jump to content



Photo

Ultra arm lift range


  • Please log in to reply
13 replies to this topic

#1 Matteo Quagliano

Matteo Quagliano

    Advanced Member

  • Sustaining Members
  • 423 posts

Posted 01 March 2009 - 12:34 PM

Hello everyone

Dos someone know Ultra arm lift range? Not considering the sled but the lowest and highest lbs load capacity that the arm can carry maintaning its behaving. I need to know because I might use it with a light sled so I would like to know especially the lighter load for that arm.
Thanks in advance for helping

Matteo
  • 0

#2 Jerry Holway

Jerry Holway

    Advanced Member

  • Sustaining Members
  • 737 posts
  • Philadelphia

Posted 01 March 2009 - 12:48 PM

Ultra/Master Series arm spec: 20-45 pounds payload (about 40-65 total). Usually both a bit more and less than the specs. You can also add rubber bands across the opposite diagonal the reduce the arm's lift power.

Jerry
  • 0

#3 Matteo Quagliano

Matteo Quagliano

    Advanced Member

  • Sustaining Members
  • 423 posts

Posted 01 March 2009 - 01:32 PM

Hi Jerry
I take the chance to thank you for The book. I'm going troght it in one way from the beginning in another picking up from the index.
Do you mean detuning the arm? I read it's recommended to be done from experts.
Or can I do it by myself?

Matteo
  • 0

#4 JobScholtze

JobScholtze

    Advanced Member

  • Sustaining Members
  • 1361 posts
  • Netherlands

Posted 01 March 2009 - 02:09 PM

Matt

Jerry means that if your load is higher then the maximum of your arm, you could add some rubber bands so it carrys more. Not that you want to carry more though.
  • 0

#5 Jerry Holway

Jerry Holway

    Advanced Member

  • Sustaining Members
  • 737 posts
  • Philadelphia

Posted 01 March 2009 - 04:43 PM

Matt

Jerry means that if your load is higher then the maximum of your arm, you could add some rubber bands so it carrys more. Not that you want to carry more though.

And you can do it in reverse; put the rubber bands on the opposite diagonal from the springs and decrease the load several pounds.

De-tuning is also possible to reduce the maximum lift, but performance suffers a bit as well (and it's a pain as the book points out). I'm talking commercial rubber bands that you buy in a box of 100 in an office supply store.

A fancier (and bigger effect) is to use O-rings, but there are many, many sizes and materials to choose from.

Lynn Nicholson sent me a set years ago that he had really researched well, but I haven't a clue exactly what they were made of or the size.

Jerry
  • 0

#6 Matteo Quagliano

Matteo Quagliano

    Advanced Member

  • Sustaining Members
  • 423 posts

Posted 02 March 2009 - 03:46 AM

I google rubber bands but I have no idea how this things can get inside an arm without messing all. Are the same as Delrin or nylon spacer mentioned in the book? Do you have a pictures of this rubber bands? And may be some of the rubber bands in place to show how the arm look like at the end of the process?
I'm getting confused...

Edited by matteoquagliano, 02 March 2009 - 03:48 AM.

  • 0

#7 JobScholtze

JobScholtze

    Advanced Member

  • Sustaining Members
  • 1361 posts
  • Netherlands

Posted 02 March 2009 - 04:20 AM

Matt,

No, Its not inside the arm. THIS LINK explaines it al.
  • 0

#8 Matteo Quagliano

Matteo Quagliano

    Advanced Member

  • Sustaining Members
  • 423 posts

Posted 02 March 2009 - 04:45 AM

Hi Job,

As usual many thanks my friend, you're really helping me a lot. Just to summurize and to check if I got this right. In the picutre Erwin posted this technique is used to beef up the arm (meaning to make it capable of carring more weight) instead what I should do is the opposite, meaning to put the bands in the other 2 holes in the arm to go opposite from the diagonal spring inside the arm.
Do I get this right? It looks very easy indeed, is it good performing as well?

P.s. after watching for some minutes to this picture I think I got the concept, it just force the arm to stay open in a way that to open it really and carry the weight is needed less weight. The opposite to beef up, it just make it harder for the arm to open in a way that more weight is needed to open it and make it works properly... WOW...

P.s.2 you do this only when you reach an end (both sides) on turning the knob, right?

Edited by matteoquagliano, 02 March 2009 - 04:50 AM.

  • 0

#9 Jerry Holway

Jerry Holway

    Advanced Member

  • Sustaining Members
  • 737 posts
  • Philadelphia

Posted 02 March 2009 - 08:51 AM

Thanks, Job, for doing the research... saved everyone lots of time and words.

Matteo, yes you now understand and have it right. Only add the bands (to make the arm lift either more or less) when you have reached the end of the normal range.

A warning to owners of very light arms (Pilot/Flyer) - the bones and bearings won't survive if you add a bunch of rubber bands to significantly increase the lift... everything will twist.

Note that a 5-6 pound increase in an arm that lifts 65 pounds is only about 8% more... If you do the math for a 10 pound maximum arm, you should only increase it less than a pound (a waste of time, I think). Adding 5 pounds to a 30 pound arm may not be safe - it's not the slow, easy moves that will get you, but that hard acceleration or bad bump that so quickly takes you beyond the safe zone.

Jerry
  • 0

#10 Matteo Quagliano

Matteo Quagliano

    Advanced Member

  • Sustaining Members
  • 423 posts

Posted 02 March 2009 - 09:02 AM

Thanks Jerry

I do understand now. The proportion remains the same even in decreasing? Let say 40 lbs minimum load can become 35 lbs minimum load? Should I ask to reduce the minimum load in house (that is possible) or should I go for rubber bands?
And last but not least... Master arm is the same as Ultra arm???

Forgive my poor knowledge but going deep trought The book doesn't clarify this for me ;)

Matteo
  • 0

#11 Jerry Holway

Jerry Holway

    Advanced Member

  • Sustaining Members
  • 737 posts
  • Philadelphia

Posted 02 March 2009 - 09:52 AM

Thanks Jerry

I do understand now. The proportion remains the same even in decreasing? Let say 40 lbs minimum load can become 35 lbs minimum load? Should I ask to reduce the minimum load in house (that is possible) or should I go for rubber bands?
And last but not least... Master arm is the same as Ultra arm???

Forgive my poor knowledge but going deep trought The book doesn't clarify this for me ;)

Matteo


You can decrease the load even more, but at some point the arm doesn't work as well; gets centered and reactive (less and less isoelastic). You've got to do the hard research (tests) to see what works for you. Also remember you can always add some weight to the camera or sled if the camera is too light.

The Master arm and the Ultra arm are essentially the same; major revisions to the 1st MS arms (1995) and smaller revisions and tweaks after that created the "ultra" arm...
  • 0

#12 Matteo Quagliano

Matteo Quagliano

    Advanced Member

  • Sustaining Members
  • 423 posts

Posted 04 March 2009 - 10:02 AM

Ok. Sled is 12 lb (with monitor and just one battery otherwise it's impossible to have a decent drop time with light cameras), if I work with betacam-like camera (19lb) I'm close to minimum weight and probably just adding a battery at the bottom can help. But if I work with hvx200-like camera (6/7 lb) then seems impossible to reach the minimum level. At this weight range is it safe and good to reduce load capacity of a master broadcast arm to fit these working load or is it just easier to go for a different arm?
  • 0

#13 Jerry Holway

Jerry Holway

    Advanced Member

  • Sustaining Members
  • 737 posts
  • Philadelphia

Posted 04 March 2009 - 03:33 PM

Ok. Sled is 12 lb (with monitor and just one battery otherwise it's impossible to have a decent drop time with light cameras), if I work with betacam-like camera (19lb) I'm close to minimum weight and probably just adding a battery at the bottom can help. But if I work with hvx200-like camera (6/7 lb) then seems impossible to reach the minimum level. At this weight range is it safe and good to reduce load capacity of a master broadcast arm to fit these working load or is it just easier to go for a different arm?


You could get an arm with a lower weight range, but probably not with the performance you want and you cut yourself off from the bigger cameras... Unless you want to pay for a G-type arm or a PRO arm (both with wide weight ranges), you are better off, I think, with the MS/Ultra arm and either rubber bands or extra weight when using very light cameras.

The HVX 200 also needs a cage and supporting structure to mount it and the mattebox rods well, so adding a bit of steel to the bottom of the support isn't a bad idea. I used something rather flimsy that the camera owner had; if it's your camera, it's worth figuring out what mod will solve all your needs.

Jerry
  • 0

#14 Matteo Quagliano

Matteo Quagliano

    Advanced Member

  • Sustaining Members
  • 423 posts

Posted 16 April 2009 - 03:19 AM

Thanks a lot for the help.

I go for G50. I managed.

Hurrayyyyyyyyyyyyyyyyyyyyyy
  • 0




GPI Pro Systems

Varizoom Follow Focus

Betz Tools for Stabilizers

Boland Communications

Media Blackout - Custom Cables and AKS

Teradek

Paralinx LLC

Engineered Cinema Solutions

SkyDreams

IDX

Ritter Battery

Omnishot Systems

BOXX

rebotnix Technologies

Wireless Video Systems

PLC - Bartech

PLC Electronics Solutions