For my Final Project, I plan to build version 2 of the tensegrity table I built for the upcycle project. I aim to make the next version an adjustable-height table that is slightly larger than my previous version. This can be used in a variety of ways, and will enable me to adjust the height of the table based on the atmosphere surrounding it and whatever it ends up holding.
Top 5 Specifications:
The idea of a table only works if it is stable enough to withstand the basic forces of things being placed on top of it on any area and not toppling over. So, I will need to create something that has adjustable tension, but also is able to withhold its tension without wobbling much or at all. I consider this as my most important specification of this project.
2. Adjustable height distance
The main difference between my first table and this one will be the adjustable height. This is likely going to be the hardest part of this project for me. I plan to use two wires for the entirety of the five tensioned sections of the table, one for the center string, and one for the four outer strings. The outer strings will be attached to one another through a pulley system (like the one above), with a final pulley that has a crank shaft to adjust the tension. The center wire will be the same as my first version, but also features a pulley with a crank to adjust that tension as well. These two together will allow me to adjust the two wires individually to adjust the table height and tension. I will also have to devise a way to lock the pulleys into place once the desired tension is reached. This will be done with a ratchet system like a bike free wheel but with a release point to lessen tension.
The size of the table is important because a tiny table isn’t what I want to take out of this. On the other hand, if the weight of the table is too high I won’t be able to adjust tension easily due to the cables having to be higher strength. I aim to make this table slightly larger than my previous version so about 3 ft by 2 ft or something along the lines of that for the top and bottom surfaces.
4. Clean Look
The point of this table is to be an aesthetic piece that I can showcase in my house, and also use as a practical table. Therefore, I want it to look presentable and clean. I may try to match the aesthetic of my first table, but also may incorporate metal for the rods attaching the center wire to get extra strength.
The strength of the table is important but not a super high priority. With adjustable height, the table strength will depend on both the cable strength and the strength of the ratchet that holds the cables in place to keep it stable. If either of these breaks the table will collapse. So, I am going to build the table with as high a strength of a cable and rachet I can find, and hopefully it will be enough to hold 10-15 llbs on top of it at least.
Top 5 Constraints:
- Adjustable height
The most important and hardest aspect of this project will be the adjustable height. This will require some engineering and a well thought out pulley and rachet system to ensure the stability and strength of the table regardless of what height it is set to.
I would like to use wood for my top and bottom surfaces to match the aesthetic of the wood tensegrity table I previously built. However, to achieve high strength I would like to use metal to attach the top and bottom surfaces through the center wire. This is something I will have to investigate because I will have to attach the surface to a metal bar or rod in a way that doesn’t induce forces that the wood can’t handle. For example, when tensioning the wires, I don’t want any screws to rip out wood threads or create a break in the surface. To prevent this, I will try to use joinery rather than screws when attatching these pieces together.
To complete this project, I will need to buy many parts that work well together in the pulley and rachet system for tensioning the wires. I plan to utilize McGuckins Hardware and McMaster Carr to purchase parts at but have not yet investigated the parts available and how easily they will interact with one another.
Money will be an important constraint in this project because I will be limited in the quality of the parts I purchase. These parts will determine the level of stability and strength the table can reach.
5. Ratchet System
The ratchet system will be an important constraint to not overlook when completing this project. This will essentially hold each wire under the desired tension and will be a crucial factor when determining the weight load that the table can safely hold. The ratchet I want to use will be similar to the figure above, which will maintain the tension and allow me to lift the pawl in order to release the tension to increase the table height.