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8828 Front End Loader
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Click the image to download the LDraw file of this model. Model by Benjamin Wendl |
Features |
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Steering
The rear wheels can be steered using an overhead "Hand of God" control.The overhead control drives an axle connected to a pair of 14 tooth bevel gears. The second axle drives a rack via an 8 tooth pinion gear. The steering mechanism itself uses steering arms and toothed links as shown in the computer image. Note that the steering arms actually point backward in this case. |
Click for an animation of
the
steering in motion |
Bucket Lift
The front bucket can be lifted via a crank on the left side of the
vehicle. The crank is made from an engine crankshaft part.
The crank turns a worm gear which drives a 24 tooth crown. Next a
set of 14 tooth bevel gears rotate a liftarm. The liftarms make
up one leg of a 4 bar linkage which then raises the bucket.The use of a worm gear results in a system which cannot be backdriven (because the axial friction is higher than the backdriving torque due to the screw pitch angle) which allows the bucket to be supported so that it does not fall under its own weight. |
Click for an animation of the bucket lifting. |
Dump
The front bucket can be dumped via a crank on the right side of the
vehicle. The crank is made from an engine crankshaft part which
rotates another pair of crankshaft parts. The 1/2 stud offset of
these parts allows a total "stroke" of 1 stud. The crank pin
drives a pair of flex cables which connect to a vertical linkage.
The top of the vertical linkage connects to a horizontal link which
terminates at the bucket's upper lugs. Translation of the link
causes rotation of the bucket about the lower lugs.If you look carefully at the animation, you can see that the crank goes over center when the bucket is up which locks it in place and prevents it from tipping. Although I'm always happy to see the flex system used, in this case it is kind of pointless. The cables do not negotiate any curves so the same function could have been easily accomplished with rigid links. |
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Wheels and Tires
This set uses four of the smaller size foam 20x30 tires and
wheels. Keen eyed observers may note that my set actually has
rubber tires, but this is not historically accurate, it is just what my
second hand set happened to come with. This was the last set to
use these foam tires. Their replacement would look nearly
identical but be made of rubber. |
Other Views |
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Side View |
Top
View |
Back View
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Front View
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Computer Render |