I had to repair a machine today that uses a static reel to counter balance a slide assembly that has a rotary encoder on a spring reel to measure displacement.
Looked like 1/8" cable over a 1.5" pulley that the cable wrapped 90 degrees. Just looked wrong and the cable lasted 3 months. The cable is very lightly loaded, is there a ratio of wire size and diameter to use in making the right sized pulley?
Thanks,
Wes
Just looked
There are minimum recommended diameters of the pulley for every size and type of cable, aircraft cable being the most flexible and requiring the smallest diameter pulley for a certain diameter cable. Also, the alignment of the pulley is critical to reduce rubbing of the cable on the side of the pulley. Worn shafts or bad bearings will decrease the life of the cable.
John
Thanks John,
I was hoping you would be up on the channel when I got home since I was sure you knew the answer given your past occupation.
Wes
Hey Wes,
The sheave diameter should be a minimum 20 times the cable diameter, which would be a 2-1/2" pulley. While the load has a major effect, the bending radius is what causes most wear if there is no other negative influence, such as improper groove size which is very important too, or incorrect fleet angle(s).
Brian Lawson, Bothwell, Ontario.
Have something to add? Share your thoughts — no account required.
Ask the community — no account required