The goal of our project is to create a custom desk that can accommodate a child that has a tracheostomy and is on a ventilator. The desk must have the ability to change its height to accommodate when the child is standing or sitting on a chair or couch.
Our child has a tracheostomy, a ventilator, and is overall quite weak. She is homeschooled and gets anxious, distracted, and uncomfortable while working on schoolwork. She needs something that can make her comfortable and allow her to change position (standing, sitting on a couch, and sitting in a chair). We are considering any other features that will make the desk convenient and help her focus.
This project, because of its one degree of motion, gives a lot of different ideas to consider. Items like linear actuators and hydraulic pistons are used every day to raise and lower items. We have also investigated mechanical systems like gas lift cylinders and trailer jacks are notable examples of entirely mechanical systems that raise and lower objects. Aside from the methods by which our desk will raise and lower, we have researched methods that keep it portable and easy to move, such as hard or soft floor casters.
Table base using linear Actuator:
This table will raise and lower through a mechanical system using a twelve-volt power source. This idea uses a free-flouted tabletop that will use gravity to decrease in height. This design also has the ability to be stored easily because of the construction.
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Total Cost $370-410
By utilizing a prefabricated frame with fully integrated electrical components, this design not only simplifies the setup process but also ensures a safer and more user-friendly experience. This approach frees up valuable time, enabling us to concentrate on enhancing the desk with additional features that will benefit our child.
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Total Cost: $277
Crank
The crank design would require two legs that could telescope via a crank connected to a worm gear in the legs.
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Materials:
We decided to go with the prebuilt desk frame. The major benefit of building our own frame is that it would allow us to tailor it to Kiera’s exact needs. We couldn’t find a prebuild desk frame without issues (such as being too tall). But, after much thinking and discussion, we decided the issues with the prebuilt desk frame were navigable and that choosing it would likely save time and money.
Our final design consists of a few changes from the preliminary design. First, the parents agreed that the desk being slightly oversized is better than cutting and risking damage to the frame. So, our desks will use a quality frame to expand on. We tried to keep the height as low as possible while keeping it mobile and sturdy. By using side-mounted casters we can keep the desk at a minimal height, and we have picked a chair that will raise her high enough to use the desk. Second, the keyboard desk pull-out will allow her to sit on the couch and still use the desk. Finally, attachments for storage will be added to further improve the function of the desk.
A major want of the family is easy disassembly, so we have made decisions on pieces to make this easier. To note, some of the pieces will remain attached permanently because of cost.
The pieces are as follows:
Working from the ground up. The casters will be attached to a custom bracket mounted to the side of the leg assembly. By using these side-mounted casters we will cut the height down by approximately 2”.
Then, we decided on a quality frame that has dual motors that will hold plenty of weight with a nice butcher block desk top for a clean modern finish. This will be attached to the frame with threaded inserts to make disassembly easier.
Finally, storage will be made through the addition of under-mounted shelving and 3D-printed products that will give a sense of customization to the end product. The project will be finished with some artistic details that will make the desk hers.
We measured the stress on the top of the table (0.195 lbf/in^2) and the stress on both legs of the desk (17.5 lbf/in^2) for each leg.
We measured stress due to the force applied on top of the desk and the stress on the bolts (3/8in) due to the force theoretically applied on the keyboard slide out holder.
For our third analysis, a simulation was ran on SOLIDWORKS over how well our intended final design would withstand forces acting on the desk surface.
To run this simulation we determined and approximated what materials our desk parts would be made out of:
Once we picked out the representative materials of our parts, we then ran the static simulations we intended.
First we ran a simulation with a 225 lb load distributed across the desk surface. This was to evaluate our desk’s displacement when subjected close to the maximum load that the frame was presented to withstand.
The second simulation we ran used a more commonly thought load of 30 lb across the desk surface. This was so the desk’s displacement could be evaluated when under the load of school books and a laptop.
Our initial project idea was to use butcher block for our table top to be cost effective. However, Dr. Canfield provided us with some rough sawn walnut planks. The shop did not have the fine woodworking tools needed to work this lumber, so we outsourced help from Dr. Pardue. Our first time going to his shop was the most work. We started by milling the lumber into useable planks. This process consisted of planing and jointing the planks. A planer takes material of of the width of the board. We pushed the boards through the planer many times to remove a 1/16 to an 1/8 of an in at a time. Then we used a jointer to square the thin side of the planks with the width, and finally using the square edge of the plank we cut the planks to size at the table saw. The next step was gluing the planks together. We used a domino jointer to apply pegs inside the planks to keep them aligned, and we glued and clamped the board finishing day one of this process.
The other two days we worked on the table top consisted of a lot of sanding. Luckily, Dr. Pardue has a very quality sander set up have dust collection built in. This allowed for minimal clean up and a better finished surface. While we worked on sanding, we also engraved our girls name into the top. This process was very quick and simple. Using a premade program, Dr. Pardue was able to engrave her name in just a few minutes. He applied epoxy into the engraving and sanded it smooth. The final step was the apply rubio monocoat. This is a simple finish to apply by spreading it evenly and buffing the surface just like buffing a car. Now the wood tops were ready for final instillation.
The frame was assembled with no need for cutting or welding. However, the team encountered a challenge with the desk’s mobility. They had to brainstorm a solution that would not increase the desk’s overall height, as it would exceed the maximum height parameter. To address this issue, we designed an L-shaped bracket to mount at the bottom of the desk and attached the casters on the side. This ingenious solution allowed the desk to remain mobile without altering its height when not in use. By carefully considering the problem and devising a creative solution, the team successfully built a functional and practical desk.
To add extra features to our desk, we decided to create two 3D prints that would be beneficial to our child’s utensil storage. The first print is a cup holder with sections that are meant to hold pencils/pens and a calculator. The second print is a headphone holder that is designed to slide on to our desk for use. Both objects are meant to be easily removable in case the child or parent wanted to change the position of the objects.
Fabrication of the Cup Holder and Hangers:
In creating these 3D objects, we first found an STL file online for the cup holder and hangers that we believed to be best suited for our intentions. Then, we loaded the cupholder’s file onto a 3D printing splicer. The settings for this object were set to have a 20% infill and use Black ABS as the printing material, and then the object was spliced and set to print on a 3D printer. After that, we loaded one copy of the cup holder hanger onto the splicer and set the settings to the same infill previously used and in Black PLA. The hanger was then loaded onto the 3D printer for a test print. Once the hanger was determined to be the correct size for our table, we spliced two more hangers to be printed in Black ABS and set those objects to print. Once all the parts were printed, we counterbore the screw holes on our hangers so that the screws do not stick out. Once that was done, we attached the cup holder and the hanger together with the needed screws, and we then added masking tape to the hanger’s clips so that it did not scratch the table.
Fabrication of the Headphone Hanger:
We began creating this 3D object by finding the ideal headphone hanger STL file online. We then loaded this file onto a splicer and set the file to print in ABS with a 20% infill. After loading the file onto the 3D printer, we set the file to be printed as a test. Once that first print was created, it came out in several different colors due to different types of ABS filament being used once a spool ran out of filament. Also, the test print was found to be slightly loose when attached to the desk. So, we decided to reprint the part at the same size and in Green Tough PLA, so that it had a uniform color. Once the reprinted object was done, we attached 3 thick circular felt pads to the clip portion of the print, so that scratching of the desk could be prevented and so the part would be securely attached to the desk.
Moving The Desk:
Changing Desk Height:
Our project required us to make a desk that could raise, lower, and pull up to a couch for comfortable use while homeschooling. To accomplish this, we bought a standing desk frame with built-in motors to control raising and lowering. We created the desktop out of walnut boards. For easy couch use, we added a slide-out keyboard tray. For storage, we added a book compartment underneath the desk. For easy movement, we added casters that can be activated and deactivated as needed. Lastly, for quality of life, we added some 3D-printed parts and a 3D-printed toy.
It is awesome that this class allows us to learn engineering concepts while helping others. Our team came together to communicate, plan, and work effectively. Though there were disagreements along the way, we made several decisions that ultimately resulted in a desk that exceeded our expectations. It came together nicely and will be something she can hopefully use for years to come.
