3D Printed Chiming Clock

Okay the second version of the Escape Wheel was better than the first, but still was not a complete success. This time it was not possible to adjust the pallets to prevent the escape wheel from free running, or jamming. And of course that means that I've a made another version to test. This time around the teeth on the Escape Wheel are more like spokes than teeth. This design allows the pallets to be in full blocking mode for the next tooth before the current tooth finishes pushing the opposite pallet out of the way. I did however have to add 20mm to the diameter of the Escape Wheel in order to thick enough (4mm) teeth with sufficient space between the teeth.

Upper Pallet detail.

Lower Pallet detail.

Hopefully this version will work better.

I printed a copy of the Escape Wheel and the Graham Yoke to test how well it would work. Well it mostly worked, but would occasionally hang up, and was quite rough in spots. So I decided to go back to basics and redesign both the Yoke and the Escape Wheel. This version of the Yoke has adjustable pallets, and the Escape Wheel has a negative rake on the teeth to provide relief to the pallets as they over travel. With regards to the Yoke over travel, this design allows for three to four degrees of over travel in each direction. As this a Graham Yoke the escape wheel is held stationary while the Yoke over travels with the pallets just sliding along the tip of the Escape Wheel tooth. This hopefully means that I can sand the striking and sliding surfaces along with the tips of the Escape Wheel teeth to make the operation smooth and quite. With adjustable pallets it is possible to setup the Yoke so that the inactive pallet is in position to block the next tooth on the Escape wheel just before the impulse portion of the cycle is finished.

To help visualize and verify the design I did a quickie Python script to animate the escape operation

Upper pallet detail.

Lower Pallet detail.

Now I just need to print the new parts and see how well it works. I will up load the new design to replace the not so good ones.

And Just because I think It looks cool, here is the animation in an isometric view.

I updated the ZIP file to have the new Yoke and Escape Wheel, a few changed files that were fixed to make them easier to print, and the Back Frame parts that need to change to accommodate the new thicker Yoke design.

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I added a full collection of STL and STEP files and a link to a GRABCAD model that has all of the FreeCAD files as well. I am planning on making one for a Christmas present, and I thought that others might want to do the same so I made sure that the current version of my design is available. If I nee to make changes I will post them as needed.