Mark

I was a member of the EAA years ago for this benefit. They offered it with an educational license to the full software.

I love sketching stuff. Originally learning on a drafting board, I find it makes me think of the whole part in my mind without 3d modeling exposing the issues for me. A few seconds with a pencil and features are scaled relationally without the need for actual dimension, and not fight the software to create something you are still figuring out. I have not tried the tablet approach to sketch and save easily. Draw directly onto a screen shot. Does this method work for others out there?

I have always preferred the 10-32 variety. This might only be because I can get a #6 and a #8 with the same thread pitch so it seems more uniform. #10-24 just seems dirty. I do actually prefer to use fine threads on the larger sizes as well but those are not as common and add to assembly time.

If there was ever a question to ask 30 people and get 30 different answers, it is this. I have a base level creality FDM printer and cant say anything bad about it. I would suggest a low cost entry level that has lots of online support so you can learn the ropes and see what changes do what. Then upgrade to the fancy stuff like Noah here.

Now it’s time for the rubber to meet the road. The model has been designed in CAD, Small parts have been built and tested, what could go wrong. Using a Biesse 5 axis router I was able to easily bring the CAD parts to life out of ¾” laminated plywood with minimal scrap. The complete cabinet was comprised of three sections: the electronics area, the TV area, and a small storage area. The center section holding the TV was the first to go together. To power the upward movement of the TV a 200-pound actuator was used. Attaching it to the back of the tv sled just below the top roller bearings allowed the top bearings to reach the end of their track and then kick the bottom edge of the tv out into position. Below is the TV sled mounted in the cabinet and a close up of the finished track sections. The bearing slides can be seen at the top of their paths for the TV section and the TV mounting plate all the way in viewing position. The vertical path mid-way up and the hockey stick path next to it are for the mid panel door. The pocketed-out section along the TVs lower guide path is for switches to detect the bearing slides and a chase to hide the wires in. For the mid door panel movement, I got the assembly to this point with no real plan for how it was going to move. My initial idea was to have the top ride on bearing slides and use a gear motor and create a rack and pinion setup to allow it to climb up. I created a gear design and a rack that bent over the hockey stick. In theory it worked and managed to drive the door up and down a few times but, in the end, if either side got bound up slightly and out of time with the motor on the other side, the gear would strip itself on the shaft. This didn’t give me confidence to move forward with this design. I was forced to rethink how to use the space I had. The door needed to move up 15” from the parked position to closed. An actuator would be the easiest solution but finding one with that much stroke and still compress down under 13” to fit below the TV wasn’t going to happen. Then I thought of a forklift, and the new actuator driven pulley lift was created. With only 8” of stroke I could get more than enough door movement. The new door system uses 3D printer belts that roll over pulleys on the end of the actuator. This set of pulleys also is constrained to the door via a 3D printed track. Now I can have a smaller short stroke actuator positioned closely to the door leaving ample room for the TV to fit behind it. The force from the actuator caused the front panel to bow out so this rib was installed to keep it straight. Time to test the motion. Video attached PXL_20210608_032115580.mp4

As part of the deal in getting a super large TV, it was agreed that we didn’t want it to be in your face as soon as you came in the room or block the opening between rooms. The tricky part here was getting a TV with a 37.5” screen height to fit under a shelf only 44” tall. First option, put it in a cabinet with bifold doors to hide it. This would keep it hidden and short, but we would also be looking down on it at the floor and the large doors could get in the room space. Second option, run the tv straight up out of a cabinet. This does keep the room clear but now we are having to look up at the tv and it blocks all vision between rooms. Third option, automate the tv movement and panels to reveal the tv. Now I can get the center of the TV at a height of 41” to match eye level on the couch and keep all the panels contained in the alcove space. To Solidworks! Quickly I modeled up the alcove space I had to work with and started sketching mechanisms. I did use some doodles on pads of the early mechanisms but it was nice to see multi link pivots and swings work in a fully constrained environment. Initial thought was a link bar system that would swing the TV up and out at the same time. After a few iterations of this it was deemed either too complicated or not controllable enough to achieve the movement required. So I moved onto sliding the TV up tracks. This would give me precise controlled movement but lacked the ability to orient the tv one way and present it another. This is how the roller bearing slide was created. The stacks of bearings allow the block to be tightly constrained into a channel while they are mounted to another block with a large bearing allowing it to swivel around bends in the track. There are an additional set of bearings on the face to keep it from scuffing up the surface if the load shifts. This almost worked better than expected and really opened the door in the design. (Need at least one dad pun) Time to build some tracks, then on to assembly.

When my wife and I purchased our first house there was one thing I knew I needed ASAP, a huge TV. What was currently in the living room did not appeal to either of us and definitely did not fit into the goal of video over indulgence. I spent a fair amount of time on the Rtings Website and settled on a 75” Samsung for our space. Now where do we put it? There was already a built cabinet and TV space but this did not fit our style and did not have the space required to accommodate the larger sized tv. This cabinet had to go and the space was refinished to house what would come next. Step 1: Remove old cabinet Step 2: Demo to make space As seen in the second image, the top shelf of the alcove was shortened back to allow for added TV height without encroaching into the room. Now onto design...