This week we manufactured the other module of our machine: the cart. Before break we had already used the water-jet to cut out our base plate. Earlier this week we finished making most parts of our cart. This went rather smoothly. However, we encountered some difficulty when making the sleeve for the arm through the center of the cart. We tried to cut and bend the hollow aluminum tube, but the aluminum started to fail before we could make the desired 90 degree bend. We solved this by using the 90 degree angle stock to make two supports then threaded the walling of the hollow tube, thus eliminating the need for the bend. To add traction to the wheels we covered them in the rough velcro. This creates an extreme amount of friction between the wheels and the carpet covering the top of the arena. The finished cart can be seen below.
With only a few days left before our machine is locked up, we have to make a few quick modifications / additions. First of all the motor drive shaft is supporting the gear as a cantilever. This put a large axial load on the drive shaft. While testing we could actually see the drive shaft being deflected down. To fix this we are creating a small pillow block for the unsupported end of the engine drive shaft. We are scheduled with mill time monday, and the piece has already been cut from the 1/4" angled stock. We will also have to mill mounting holes in the cart base. Below is a picture of where the new pillow block will be added.
Another error we found was the possibility of the cart jamming itself by running sideways in the arena slot. By prevent the tube sleeve from turning we can prevent the whole cart from rotating. We will achieve this by mounting delrin sliders on the sides of the tube below the cart. These sliders will extend forward and ensure the cart drives straight. We have already used the laser cutter to cut out the delrin sliders, but need to drill holes in the side of the sleeve tube. Due to the lack of space within the arena slit we are planning to secure the sliders to the tube using a rivot. If need be, the rivot can be sanded down and will slide nicely along the arena wall.
With only a few days left before our machine is locked up, we have to make a few quick modifications / additions. First of all the motor drive shaft is supporting the gear as a cantilever. This put a large axial load on the drive shaft. While testing we could actually see the drive shaft being deflected down. To fix this we are creating a small pillow block for the unsupported end of the engine drive shaft. We are scheduled with mill time monday, and the piece has already been cut from the 1/4" angled stock. We will also have to mill mounting holes in the cart base. Below is a picture of where the new pillow block will be added.
Another error we found was the possibility of the cart jamming itself by running sideways in the arena slot. By prevent the tube sleeve from turning we can prevent the whole cart from rotating. We will achieve this by mounting delrin sliders on the sides of the tube below the cart. These sliders will extend forward and ensure the cart drives straight. We have already used the laser cutter to cut out the delrin sliders, but need to drill holes in the side of the sleeve tube. Due to the lack of space within the arena slit we are planning to secure the sliders to the tube using a rivot. If need be, the rivot can be sanded down and will slide nicely along the arena wall.
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