Help with Pullys.....

Red Sea Purple Tang

Active member
LightRack2.JPG


Here's the issues: We're finishing the sheet rocking in the fish room and have changed the plan to have the lighting rack on the existing pully system.

- The pully's on the rack (sitting on the tank in the picture...disregard the two verticle PVC pieces) are equally distant from both ends.

- The pully wire with the green arrow, upper right of the picture, will be used to lowering/raising the rack.

- Will this pully orientation allow the rack be raised/lowered?

Any idea from you engineering gurus? :rollface:
 
Or....I could just make another rack with support pullys below. While it wouldn't be exactly lifting the rack equal distant from each end, I could weight one side to off set that... ???

LightRack3.JPG
 
They are both good solutions and should lift your lights just fine. Regardless if what solution you use, the whole system will be able to change level. IE: one side lower than the other. To remedy that you would want to use two seperate pully systems with two wires. Much like a window blind. Where the two separate wires are tied togather so the operate uniformly.

Take this with a grain of salt tho :)
 
Anthony,

I agree with sero. When you pull on the cord the lights will raise unevenly. If your intent on having only one cord, you with have to center the cord and balance the end. Does that make sense?


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I know crude drawing but maybe you get the drift?

Fishing for an invite when your done tho.

Tom
 
The crude drawing doesn't look what I put on there befor posting. I'm sorry. I'll try harder.

Like a beam scale and block and tackle is what I was after.

Tom
 
They covered it on the CMAS board. Basically, a beam to support both ends of the lighting and a center center rope that forms a triangle and a series of pulleys that the rope loops through to raise that lights equally. I will try and find a diagram.

Tom
 
Referring to the most recent picture in the thread, you've got 5 pullies. Let the top be A, B and C from left to right. The bottom two we'll call D and E from left to right.

Try to imagine this:

Right now you have one pulley system, let’s turn this into two pulley systems. A, D, and B are the left pulley system; C and E are the right pulley system.

Mentally, lets cut your pulley wire, in half, at pulley B and then lets pretend it magically grows 4' longer, or so (the wire that'd be hanging from pulley A). That gives you your independent left pulley system

Where we've now got hanging wire for the right pulley system, because we cut the wire in half at B, install an additional eye hook near the B pulley location and secure your wire there. Take pulley C and relocate it right next to pulley B. You now have an independent right pulley system.

By adding one more eye hook and a few feet (whatever's necessary for your application) of wire you can have a uniform lifting system with ease. Well, assuming my explanation makes sense anyways. Simply secure the two wires together somewhere to the right of pulley C, so when you pull the wires they move uniformly. Plus, you won't have to worry about uniform distribution of the weight :) !

HTH!
 
Anthony,

Are you looking for something that will slide out you light fixtures? Are they mounted to a frame?

I was thinking maybe you could use heavy duty, full extension drawer slides. Rockler on Hwy 100 carries them. If they are protected from salt spray they should be fine.


Tom
 
<a href=showthread.php?s=&postid=8393522#post8393522 target=_blank>Originally posted</a> by Red Sea Purple Tang
The track would be mounted to the ceiling.

I guessed that.

I was just wondering if the lighting would get in your way if you are working on the tank. Unless, it pulls out farther then the working area. I have seen these on the TOTM and I always wondered that.

Tom
 
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