Aluminum part for proof of concept

[Larry G]

We are developing a low-power mechanism to wind up the actuating cable pulling a "web" of thin material.
Think of a window shade without an internal spring. The circumference of the roller with the shade changes continuously.
The circumference of this component varies to match the windup and payout of the shade.
A FUSEE was developed hundreds of years ago, used by clock makers to compensate for the diminishing torque as the mainspring unwound.
The item is modelled in SolidWorks, any other format is available.
The full radius at the top of the .020" "fin" is not really required, just breaking the edge would be sufficient.
Very small ceramic media in a vibratory finisher would probably suffice.
I'm looking for a quote for onsey-twosy at the moment, as well as suggestions to optimize the manufacturability of the part.

Thanks,

Larry in NJ

 

[DDoug]

Looks similar:
Garage Door Vertical Lift Cable Drums D1100-216 (Pair) | eBay

 

[Larry G]

The garage door cable drums are exactly the same as the clockmaker's application.
Ours uses the same principle but not to compensate for torque, but rather for varying circumference.
Our application puts the fusee and the web roller on the same shaft.
A pair of them are arranged parallel to each other with the web portions forming a closure (pair of window shades meeting at the center).

Is there a tragic flaw in the design that would cause the manufacturing cost to blow up?
Looking for a quote from anyone interested.

Thanks for the link.

Larry

 

[sfriedberg]

If you eventually go to large numbers of these, you will probably want them cast rather than machined, for economy. In that case, you might consider making the retaining flange ("start of track" side) a separate simple piece which fastens to the main part. This would simplify pattern/mold making and drawing the parts from the mold.

 

[Peter from Holland]

Rounded bottem of the cable groove perhaps
Makes casting easier too if you go that route

 

[Larry G]

Rounded bottom of the cable groove perhaps
Makes casting easier too if you go that route

The bottom of the groove will be rounded with a stock key-cutter tool.

Thanks for the comments and thank you to the moderator of this sub-forum for his offer to help, awaiting his quote.