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Saturday, September 12, 2015

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




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