| Side view, showing actuator handle at the top and
spring assembly captured between 1X8 plates. The fixed block is at the top and the
floating block slides up and down, at the bottom. |
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The cage separated. The cage was necessary
in this first version to keep the floating end captive. |
| Here is the Block & Tackle mechanism
exposed. See that there are two spring assemblies and four pulleys. The upper
block is fixed by the triangular LEGO piece between the pulleys, the corners of which are
attached to the cage. See that the fishing-line is attached to the bottom of the
triangle. The handle pivots on the same axle as the pulleys. |
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At one position, spring relaxed |
At the other, spring compressed |
So... it's a spring-loaded handle, sort of. What's it
good for? It would be a great throttle quadrant for an aircraft (even looks like
one)! I would recommend it as cannon lockwork for firing ping-pong balls.
I have been carrying it around for a week. The action is
silky smooth, and it just ...feels good... Only a LEGO nut would understand.
But mostly, it is an example of a mechanism we rarely
use. It's a solution looking for a problem. Let me know if you find a use for it.
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The LEGO Spooler, elsewhere on my site, uses an
inverted Block & Tackle mechanism. Here, both ends of the film are free at a
tension that is constant at 1/4 of the weight, a benefit. For every cm that the
weight rises, 4 cm of film is released. This increases the controllability of the
system a lot, also a benefit. |
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