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8040 Pneumatic Universal Building Set
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1st
Model: Dump Truck |
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This
truck
has rack and pinion steering and a pneumatically dumping bed. The front wheels can be steered using an overhead "hand of god" wheel. The wheel drives a set of 14 tooth bevel gears attached to a pinion. The pinion drives the steering rack. The steering mechanism itself uses control arms and toothed links. The pneumatic actuator dumps the bed by simply pushing it so that it pivots about a rear axis of pins (see computer image). Total bed rotation is about 80 degrees. |
Click to download the LDraw file of this model. Model by Jerome Boulanger Click for an animation of the steering in motion. Click for an animation of the bed dumping. |
2nd
Model: Plow |
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This
model
has rear steering and a pneumatically lifting plow. The rear wheels can be steered using an overhead "hand of god" wheel. The wheel drives a set of 14 tooth bevel gears attached to a pinion. The pinion drives the steering rack. The steering mechanism itself uses control arms and toothed links. The pneumatic actuator can raise the plow via a 4 bar linkage which always keep the plow perpendicular to the ground. |
Click for an animation of the steering in motion. Click for an animation of the plow lifting. |
3rd
Model: Car |
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This
car
is a cool idea for pneumatically driven steering that didn't work
out very well. The pneumatic pump is attached to a crank on the rear wheels. The crank is simply a 24 tooth gear using an offset hole to produce reciprocating motion in the pump. The actuator is attached to the steering linkage and is at approximately half stroke with no steering angle. Theoretically, the pump will produce pressure when the car is moving, and the switch can be used to steer the vehicle left or right. In practice, the pump stroke produced by the crankshaft is too short to produce enough pressure to move the steering, so the whole thing doesn't really work. It works a little if you push the car very fast, but it is impossible to do so with the steering turned. It is possible that a brand new set of parts would work better. There is no animation here because there was no motion. On the other hand, you could consider the static picture an accurate animation of what really happens when this model is used. |
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4th
Model: Forklift |
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This
forklift
features rear steering and pneumatically lifting forks. The rear wheels can be steered using an overhead "hand of god" wheel. The wheel drives a set of 14 tooth bevel gears attached to a pinion. The pinion drives the steering rack. The steering mechanism itself uses control arms and toothed links. A pneumatic actuator can lift the forks via a 4 bar linkage which keeps the forks parallel to the ground. |
Click for an animation of the steering in motion. Click for an animation of the forks lifting. |
5th
Model: Log Loader |
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The
log loader is a neat little model with a luffing boom and a claw which
can grab by opening and closing. There is no steering in this
model. A pulley wheel used as a crank turns a pair of 8 tooth spur gears. One acts as a ratchet and mates with a rack gear used as a pawl. This supports the weight of the boom. The other drives a 24 tooth gear which, in turn, drives another. This last gear is on an axle which uses a pair of steering arms as liftarms. The liftarms are attached to a pair of 2x8 plates used as push rods which lift the boom. The pneumatic actuator drives the claw to open and close. When retracting, the actuator puts the pair of axles into tension which tends to make them pop out of their connectors unless they are very snug. Old cracked connectors will not work here. |
Click for an animation of the boom luffing. Click for an animation of the claw opening. |