Lego Scmihdt coupling

What’s a Schmidt coupling you might ask, A Schmidt coupling is a type of coupling designed to accommodate large radial displacement between two shafts, in the video above, that is shown very clearly, by turning the first "rack", the three beams are rotated either clockwise, or counter clockwise, which turns the second "rack", which then repeats the same action with the beams again, and then the third "rack" closes the coupling and a shaft is connected to it. A Schmidt coupling can handle very high amounts of torque. There is no limit to how many "racks" you can have, or how long the beams can be, but the longer the beams, and more "racks" in the coupling, the more play in the system. Until next time, if you can dream it, you can build it.

LEGO 10 speed transmission, 5x2

A Lego 10 speed transmission, really??? Out of Legos?? Yep that’s right, the transmission is comprised of a 5 speed box followed by a 2 speed box, and the low gear in the 2 speed box is 3:1, while high gear is direct drive or 1:1. I am unaware of what the ratios in the 5 speed box are, as they weren’t listed on the moc's homepage, and I didn’t take the time to figure them out when I was building it. The CV joint and universal joint was placed between the two transmissions to overcome the slight offset of the axle in the 5 speed. When pinned together the output and input didn’t line up so the use of the CV joint was the easiest route to overcome that problem. Now why did I make this transmission you might ask, well I wanted to see if I could, and it turned out fabulous, the 5 speed transmission is a MOC I found on Rebrickable created by neo. 1st and 6th gear will crackle when too much resistance is applied to the output shaft, the crackle is the gears jumping teeth with the next gear it meshes with. The device built on top of the 2 box was built to apply resistance to the rubber wheel, with the use of a worm gear turning an 8 tooth which is directly connected to a 4x7 bent lift arm, thus applying resistance.

I plan to build a "car" around this transmission, putting either an I6 or V8 in front of the transmission, and a differential after the transmission. The car wont drive, but it will be a model to demonstrate ratios, and torque vs speed. Until next time, remember, if you can dream it, you can build it.

Wreckers, then and now.

fig 1

fig 2

fig 3

fig 4

  In 1916 Ernest Holmes, invented the first wrecker out of necessity (fig 1), in 1916 Ernest received a call from an old professor, he had flipped his Model T Ford into a creek-bed on its roof, Ernest and 6 men, took 8 hours to pull the car from the creek. Ernest knew there had to be an easier way to do this job. A 1913 Cadillac was rebuilt to include a wrecker body on the back of it, Ernest tested it and realized the weight pulling on the rear of the truck would lift the front end up, Ernest added rear stabilizers and this time it worked like a charm. Wreckers have come a long way from the early days, in fig 2 is a 99' Peterbilt 379 flattop wrecker with a 350" wheelbase, which I will be MOCing, (my own creation) over the course of the next month or 2. I was inspired to build a wrecker as it is full of different functions, a lifting boom, rear stabilizers, extending boom, and a wheel lift built into the boom or chassis itself. I’ve roughed the chassis of my truck, and have already built the pneumatic pump, placed all 4 valves (lift, rear stabilizers, auxiliary air supply and wheel lift). In Fig 3, you can see the rough mockup of a boom I created in order to find the proper cylinder angle, if you look at fig 2, in the rear of the truck you can see the hydraulic cylinders that lift the boom, they sit at approximately a 50 degree angle in relation to the chassis. In my truck the cylinders are straight up and down, which leads to the wheel lift being too high when fully raised, although I don’t necessarily have to raise the boom all the way up. In fig 4, the rear drive set up is built very similar to the Mercedes Benz Arocs technic set 42043, two differentials, hung underneath 6 medium shock absorbers, with a driveshaft connected to a model engine, I don’t have the engine in place yet, I do plan on putting an I6 engine in the wrecker. In fig 5 you see the 4 valves that will control all the pneumatic features on the truck, the red valve raises/ lowers the boom, the brown is to supply air to the auxiliary output in the back of the truck, visible in fig 4 as the black hose. the grey and black valve don't have a function plumbed to them yet. The last picture, fig 6, shows the onboard compressor, powered by an L-motor. There is also an air tank on this truck, to help the functions run more smoothly. That’s all for now, until next time when I plan on building a 10 speed transmission. remember, if you can dream it, you can build it.

fig 5

fig 6