Jumping Mechanism
I bought my first 4th class Bucky. You have to admit, these
things are worth every penny, especially if you've ever tried
to make one.
Shown here are the results of my first attempt at building
a '"prop moving" mechanism.
I want my prop to stand upright
when the mechanism is
in its retracted state.
I plan to mount Bucky's shoulders
to the top of the "T," (the far right
side of the mechanism.)
This contraption is big enough
that Bucky's feet will be just a
few inches off the ground.
I plan to build a 2x4 base.
It will need a good footing.
I know... PVC pneumatic cylinder? It's almost a crime.
I will replace this before Halloween 2002. All of my seasoned haunt
friends advise strongly AGAINST using home-made air cylinders .
In this photo the prop is
shown at full extension. The spring
shown here has been replaced
with a bolt which
acts as a limiter.
At this point Bucky will have jumped up nearly three
feet and "lunged" forward
almost five.
Without the prop attached, this mechanism reached full
extension in about 3/4 of a second running 60 p.s.i.
The sketch at right is one of my originalconcept drawings for this lifting mechanism.
It's not perfectly to scale, nor is it perfectly
accurate, but it is a good representation
of what happens when the linkage moves.
I built a miniature working model of this
mechanism to "fine tune" the placement of
the pivot points.
At left is a "3-D" type sketch of the mechanism.The blue pieces are made of 3/16" x 2" steel
angle iron. The vertical members are 65" long
Yellow pieces are 11 ga. X 1 1/4" steel
square tube.
I used this metal as the rear brace as well, since
it is the same width as the linkage arms.
The green pieces are 1/8" x 1" steel
angle iron. Both are 48" long.
I added braces to the "legs" and rear brace at
approximately 45 degrees to the 2" vertical members.
The "foot print" of this prop measures 4 feet wide by 4 feet deep.
I decided on these measurements because they will fit on half of
a 4' by 8' sheet of 3/4" plywood. The other half will be used
as the "forward" brace. This will be attached to a 2 x 4 sub-frame.
This should keep everything upright.
These are the measurements I used for this four bar linkage.
The red portion of the lower arm could hold a counter-weight.
I will attach a double acting pneumatic cylinder here.
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