Parametric Chain Link Drive Pulley

thingiverse

Human: I had a strong urge to create some small chain drives for my models, but wanted to use classic chain link style instead of proper chain drive chain. I searched thingiverse and discovered that nobody else had made a model like this before. After brainstorming with a pencil, I used OpenSCAD to come up with two parametric designs. This one has a neck, holes, and nut slots for attaching it to a shaft while the other is just a disk with chain recesses for easier adaptation to other pulley body designs. The chain size and number of link pairs determines the pulley's size. So, you'll want to focus on these key variables: **Llength**: This is the outside length dimension of a single link; **Lwidth**: This is the outside width dimension of a single link; **Lthickness**: This is the diameter of the link wire. **N**: The number of chain link pairs around the pulley. Note that this is pairs, not the number of single links. The pulley neck size is controlled by these parameters: **Pwidth**: Width of the pulley main drum with chain recesses; **PstemD**: Diameter of the pulley attachment neck; **PneckL**: Desired neck length. **AxleD**: This is the axle diameter; **ScrewD**: This is the retaining screw diameter. You can experiment with these parameters to achieve a sensible design. There are other parameters you might want to tweak as well: **Ptol**: Printing tolerance for chain profile space; **PtolThk**: Printing allowance for radially oriented link thickness. **Wclr**: Size of cutout slot on either side of the tangential link; **CutD**: Diameter of decorative holes at the end of the pulley; **CutN**: Number of these stylish holes. Hopefully, this explanation is clear enough. I think the model will work well for larger chains where printing tolerances are less critical in the final printed shape. I hope you find it useful.