[Part 3] Mechanical Component Gathering

Ever since I finished specking out and ordering off-the-shelf items, I have been getting lots of them in my mail box quite faster than I expected. Right now I have all the stuffs from McMaster (but there is no surprise here because they are known for their superfast delivery service!) and AndyMarks. I'm going to show you some pictures of the components I bought for my UPC. 


The bearing inside the mount is designed to move (translate in all three axial directions and rotate) within the steel castings, although the degree of freedom is not significant. This is by design choice. That is, under a severe load or a certain jerk, the bearing effectively absorbs the excess force by yielding its position to the force (by translation). This bearing mount is rated at 500lbs and 2300rpm if my memory (+calculation) serves right.


This is the other side of the bearing mount. Notice that it is not symmetric. One side has a protrusion and this protrusion is supposed to give a better support to the axle. The side without the protrusion will be facing the wheel.


These are shaft collars. They will be used to make sure that the wheels don't fall out of the axle by providing translational fixation at the end of the axle. Each is rated at 200lbs of force in the direction parallel to the axle. My design only requires two of them, one at each end of the axle, but I bought two extra just in case.


These are the shaft keys. Basically, these guys provide a good fix of rotational freedom of the wheel to the axle (to make sure that the wheels turn with the axle). The wheel mates with a wheel hub which has a rectangular cut-out groove in the bore where the axle is going through. The shaft has the same groove on its surface. It happens that the depth of each grooves is exactly half the thickness of these keys. So when the grooves coincide they complete a square groove in which we slide this key in to rotationally fix the wheel to the axle. The subsequent mounting of shaft collars right next to it prevent this key from sliding out. 


This is the sheet metal edge protector. I'm using a 0.375'' Aluminum plate so the protector must be able to cover the same thickness. It feels like it is made of EPDM rubber.


This is a fuse and a fuse box. I prefer this types of fuse in which wires and the fuse can be detachable with ease. It comes with a cover (connected to the box by a string so that you don't lose 'em) so no additional insulation around the fuse is required! Another advantage of using this fuse box is that if you look at its design, there is a trapezoidal groove in the middle. On the other side, there is an trapezoidal track which has a matching dimension to the groove on the opposite side. So in case there are multiple fuse boxes that need to be installed, a track from a fuse box can be slid into the groove of another fuse box and they form a series of fuse boxes which I think is a pretty darn neat feature. 


This picture shows everything I've got so far. Notice the rectangular grooves in the wheel hub bores. If you had some hard time understanding what I was talking about few minutes ago regarding the whole rectangular groove thing, now is a great chance to see them in the picture.



I also bought 12'' pneumatic wheels from Nothern-Tools (the wheels from AndyMark in the picture is 8'' and it is not penumatic. The coefficient of friction is 0.95 on dry smooth surface). I guess I am not still sure which diameter will fit the best. But for now I plan to use 8'' wheels.

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