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  1. #1
    Hi Guys,

    I was getting ready to share my "great invention" with you when I decided to do a patent search. Sure enough, someone had a similar idea way before I did :) On the positive side, it will spare me from a lengthy write up.

    The patent has now expired so if you are looking for a simple belt reduction with zero backlash between the pinion and the rack check this out. It considers gear on gear but you can substitute the large gear (26) with a rack and two pinions (28 and 30).

    The principle is that you have two pinions riding on the rack with each of them having an opposite tooth pre-load applied by the tension of the belt. Each time direction change occurs, the preloaded tooth/pinion drives the rack so no backlash. There are no torque limitations, which can be a problem with split pinion system demanding high accelerations.

    Click image for larger version. 

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    Instead of driving one of the pinions (28) directly, as illustrated, I have a small pulley driving the two larger pulleys via a belt which offers 1:3 reduction.

    Click image for larger version. 

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    I made a 3d printed prototype, which works great. Iill be ordering the machined parts soon.

    Click image for larger version. 

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    The green idler barely touches the belt. The red and motor pulleys are the ones providing tension for tooth engagement on the respective pinions.
    Last edited by deemoss; 15-04-2019 at 10:03 AM.

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