Crown pulleys

[Bsmith]

Video I came across by accident.
I have wondered in the past why some brush/beater on upright vac cleaners have a crowned pulley.

https://www.youtube.com/watch?time_continue=52&v=6sM0Qjumyro

 

[ms08]

Yes, have one on my belt driven Hi Fi turntable - belt always stays in the middle.

 

[rtbcomp]

Back in the 1970s I worked on computer equipment that used a flat belt to drive a disk at several 1000 rpm, also some washing machines use crown pulleys and flat belts.

 

[optima21]

I have a 1" wide belt sander, I needed to exadurate the pulley crown to help the belts on the pulleys, any side pressure on the belts and they used to fly off.

 

[brightspark]

it doesn't need to be a mental angle. my 6 inch belt sander only has about 3/4 of an inch in either side and less than a 1/6th taper