Planetary Gear

Coupling a Lifter to an output system that can extract the stored energy of a tilted up Carriage is really important. The efficiency of a Lifter while tilting up the Carriage and in letting it descend is fairly easy to keep high. On the output side, that is another issue. Mechanical assemblies such as belts, pulleys, sprockets, chains, etc. all degrade the overall efficiency of a Lifter system. So, I was happy to find this planetary gear head. It has taken the place several large pulleys, belts and associated hardware. Plus with this addition it is easy to add additional low torque stages.

The planetary gear is a, SUMITOMO SM-CYCLO Planetary Gear Reducer CNVMS-5095-43. I found it on e-bay and you can search there to see other SUMITOMO gear reducers. This one has a ratio of 43:1. I put a 4" sprocket on its input so that the second stage of the Lifters prime mover could drive it. The low torque, high rpm, input is used as the output for the Lifter. I had to trim down the input shaft from 1.261" to 1.25" for the 4" sprocket to fit and also had to trim the very large key to fit partly into the key slot of the sprocket. From the specs on SUMITOTO planetary gears I believe that they claim around 86% efficiency for this size speed reducer. Ones with a larger reduction are less efficient. Overall, this reducer has worked very well.

Another item that is new is the use of a roller chain to help controlling the speed of the Carriage as it descends. I noticed that there is a product called, Petzl® ZIGZAG® Mechanical Prusik. You can read about it here:

http://www.forestry-suppliers.com/product_pages/Products.asp?mi=49570&itemnum=27379

Mine isn't quite as good as theirs, but it does work well enough to allow for some speed control. It gives me the ability to overload the Carriage to get additional time at the output without having to add additional reduction gears. ( I mistakenly said, in the video, that it was a "pretzel", ha! Close....

In this video I introduce the new planetary gear and the speed control assembly. I have also added, for output, a Magnic Light. The spinning aluminum rimmed wheel, used to energize the lamp, is attached to the output of the Lifter with a speed odometer cable. The Carriage is carrying 12 thirty pound blocks and with the weight of the Carriage, that adds up to around 440-460 lbs. Using my Zigzag like roller chain speed control I was able to adjust the output of the light and the speed at which the wheel rotated. I tilted the Carriage up to eight feet in 15 minutes and allowed it to come down. The drop time varied to between 12 and 15 minutes per foot, with the light output varying to the drop time. The drop time was about 90-120 minutes. By adjusting gear ratios, Carriage weight and drop time, the brightness of the light may be increased or decreased.

Planetary Gear and Speed Control