This little sculpture was built on a deadline - I had one week to complete the project. The deadline was a combination of the organizers needing something by the first of August and my being away for the last three weeks of July. Therefore only one week was available.
The project size and shape was constrained by the “pumpkin shape” that was supplied by the organizer.
My daughter likes to work with geometric patterns and made one something like this and then over-laid another to produce some interesting designs.
With this in mind I started by just doodling on a scrap of paper.
The design objective was to create a kinetic sculpture that would allow interaction with the public - ie the public could “play” with it.
I wanted to make the sculpture as fool proof as possible and so I opted for a “chain drive” mechanism
Simplicity was the order of the day and the unit contains a minimum of moving parts.
A drive wheel, a second wheel, the fan, and the “sculpture” wheels.
The winding of the unit to “make it go” is through a lever which is limited by stops that only allow for a 77º winding angle - the driving weight is on the end of this lever
The lever carries a 20 toothed ratchet and silent pawls are mounted on an 8 inch drive sprocket.
The desired run time is only one minute or less depending on the control supplied by the fan and the drive weight.
The arithmetic says that the drive wheel will go 77º and the sculpture will turn 2.6 times and the fly 124 times.
The drive wheel is “geared up” 48:1 to operate an 8” - 12 paddle fan. An 8:1 is obtained by the chain and a further 6:1 by gear drive
In line with this fan regulation drive are two wheels with a geometric pattern cut in them. The two wheels are counter rotated such that one goes clockwise while the other counter clockwise.
The finished unit looks like this and will be nailed to a wall and the public invited to operate the lever.