A figure in a crouched position slowly rises to a towering stance, all the while spilling his fog soul.
Originally, this project was to be based on a simple four bar lifting mechanism.
As with every other planning session, ideas were roughly sketched out for future reference
and consideration. Construction commenced with the decision to build an angled, rear swinging machine.
This design will help to better mimic an aggressive sort of rising motion.
The angle of the linkage base will introduce a slight forward motion to the prop body's travel.
These photos show the primary motion of the prop.
The linkage is built so that it closes fairly tightly on itself. The crank and coupler bars are constructed
to provide enough space for the pneumatic cylinder, but little more. Keeping the working portions of the structure
as tight as possible should make for easy camouflage later in the finishing stage.
Four Bar Lifting mechanism, fully extended.
The Prop base and the four bar linkage base member are cut from 14 gauge 1" X 2" rectangular steel tube stock.
The crank, coupler, and follower bars are cut from 16 gauge 1" X 1" square steel tube.
Linkage bar additions/extensions are 1" X 3/16" flat steel.
The main lift will be powered using a 1 1/4" X 12" Clippard Air Cylinder.
Part of the original plan was to add a simple body armature that would carry a prop head and hands.
That plan failed early in the build process and was replaced with a better plan ... basic arm animation.
The "spine" bar is 3/4" 16 gauge square steel tube.
Providing that the four bar follower is made using 16 gauge 1" X 1" stock, the spine will fit inside.
A couple of 1/4" bolts secure the joint, but the components can be separated if desired.
When the (main) four bar lift nears full extension, a mercury switch mounted to the linkage will actuate a second
motion, the arm lift linkage. This linkage is really nothing more than a simple home made barrel hinge. The arm support
brackets and effort lever are attached to the "pin" portion of the hinge.
The photos above show the full range of motion, roughly 90 degrees from fully retracted to extended.
This motion will be powered using a 1 1/2" X 2" Bimba air cylinder. A smaller bore cylinder would be sufficient here,
but these are among my cylinder stock pile.
Drawing of the arm support bracket (above, left)
and shoulder linkage (above, right)
The shoulder linkage is primarily constructed of 3/4" square tube.
The effort arm is 1/2" square tube.
3/16" flat stock and 1/8" angle iron were used to add connection points.
1/4" schedule 40 pipe (steel) is used to make the rotating hinge pin.
(1/4" steel sch. 40 pipe has a roughly 9/16" o.d. and almost 3/8" i.d ... where the 1/4" name comes from I have no idea ... )
The arm support bracket is also 3/4" square tube and is welded to the hinge pin.
For this prop, the arm armature had to be a separate piece. In other cases a good welded joint here would
perfectly acceptable. To connect the 1/4" round arm armature to the shoulder mechanism,
the arm support bracket is drilled and tapped to receive two bolts and jam nuts.
These effectively lock the parts together.
After testing for proper tracking and acceptable motion, the machine was disassembled, cleaned and painted.
During the final rebuild, new bolts, lock nuts, and washers are installed. pivot joints are lubricated with quality wheel bearing grease.
(Higher viscosity is a big plus in these joints.)
Air lines and electric control wires are installed. Zip ties are used to secure them to the linkage members.
Air lines and wires that are left "long" for the hinge areas are wrapped to protect against possible abrasion.
I prefer the spiral type cable wrap, but split loom tubing has it's charms.
Power supply, solenoid valves, junction blocks, relays, switches, etc. are mounted to the prop base.
Here we see the machine at mid, and at full extension.
In order to achieve the desired effect, the four bar will lift slowly.
Considering the extended size of this linkage, a slow lift is a good idea.
The Armature "head" height ranges from approximately three feet retracted to seven feet extended.
This distance, plus the angle of the four bar "base," plus the weight of the prop body would require a
larger prop base than the one incorporated here if lifted too quickly.
Instead, we'll have a slow and steady rising motion followed by a quick
"lunge" arm motion.
Here's a short video clip of the basic machine in motion.
vtv.2005.soulspill.machine.01.WMV (534 KB)
In this clip, the mercury switch is positioned so that the arm linkage "chatters."
At first, this effect seemed fitting. After a few test firings, it became quite annoying.
The switch was repositioned so the secondary motion was "on" 100 percent when the
four bar linkage neared maximum travel.
Below are links to full page drawings of linkage components.
This information is provided for any individual interested in experimenting with prop designs similar to this.
Note that these ARE NOT technical drawings ... more like food for thought.
Corkus ... again?
All of the time and effort required to sculpt and mold body parts really pays off when it's time to
create a character for your new machine.
The torso skin slides over the spine armature, and the shoulder linkage is bolted in place.
(Hence the angle iron brackets shown in the drawing above.)
The arm armatures are bolted in position, and the arm skins slide in place.
The seams at the elbows are addressed, and the arms are foamed in place.
The torso is also carefully foamed in place, making sure the cylinder and shoulder linkage areas receive NO foam.
Temporarily add the prop head, and run that bad boy for a while!
It's my opinion that when building custom or otherwise uncertified designs ...
frequent tests are a must. First manually power the motion, then run the motions via compressed air.
You'll want to know before, during, and after all progress how things are performing.
A surprise ammendment to the soulspill build plan ... Controlled leg movement.
Legs you ask? "I thought this was to be a simple head-and-hands prop body?"
Well, that plan fell apart too.
Why bother? Because we can, therefore we should.
In learning this craft, experimentation leads to experience. It's all part of the self-education process.
It's possible that gravity would do an adequate job controlling the motion of the prop legs.
There's a good chance they would bend at the right time during prop reset, folding neatly in place.
However, why not control the leg bends at the hips and knees?
By adding control arms to the existing leg armatures, you create four bar linkages.
Once installed and set properly, the motion will be predictably correct during extension and retraction
of the main lift. This level of control eliminates one "worry" later on. The legs will perform as expected every time.
The edited photo above will clarify the leg lift linkage. ("Hip" area.)
The green colored bar (the follower bar of the main four bar linkage) now performs double duty.
It is now used as the effort arm for the leg lift.
The red colored link uses the motion of the effort arm in relation to the black bar. As the main four bar lift occurs,
the coupler (black bar) and follower/effort arm (green) produce a changing angle. This change becomes a linear action
as far as the red linkage is concerned.
The red link now pushes and pulls the blue colored bar, which is the follower.
This blue bar is actually the internal rotating pin portion of another home made hinge
(much like the arm mechanism explained above)
The leg armatures (colored yellow) are welded to the blue colored bar.
When the hinge pin rotates, the thigh portions of the legs move with that motion.
Here we add a couple of additional control arm linkages to create a bending knee motion.
The yellow colored bar is the outside piece of the home made hinge.
This is mounted to the frame, so it doesn't rotate.
The movement of the (red colored) leg bar is basically controlled by the main lift, as described above.
We'll use this motion in relation to the stationary yellow bar.
As the red bar moves around the yellow bar, it generates a lesser or greater
distance from a fixed mounting point. From this mounting point, the control link (blue colored bar)
is attached to the lower leg (green colored bar).
As the distance at the "hip" area changes, so does the "knee" area, creating a knee bending motion.
Essentially, as the prop rises, the legs unfold. When the prop resets and lowers, the knees bend into
the desired crouched position.
Prop skins range-of-motion, as seen from behind.
Side view of the prop's range-of-motion.
The calf/foot castings were foamed in place, and the thigh portions of the leg castings were tied to the leg linkage.
The jaw is temporarily pinned in place for reference.
Without running the risk of mingling spirituality and Halloween entertainment, A fog machine will be added to the linkage
to visually produce this character's soul spilling forth. This is certainly no idea of mine, but piping fog to a desired location
is a neat trick. This is a combination of 1 1/4" galvanized metal conduit and vacuum cleaner hose.
The conduit is lightweight yet rigid, plus it's possible to weld mounting brackets to the individual metal pieces.
The vacuum cleaner hose maintains a tight connection from beginning to end, but will bend with the linkage as it moves.
This project was a semi-gamble situation. First, the inner diameter of the pipe is only 1 1/8." The finished length of the
assembly is over eight feet long. That's a long, skinny, vertical lift for a small wattage, small output fogger.
After initial testing, I was quite pleased to discover that the fog traveled the distance easily.
As with the electrical lines, the fog duct work requires some excess at the linkage joints.
The main four bar linkage is pretty tight when fully retracted, and the flexible hose won't make
very tight bends without kinking.
The fog duct terminates around mid chest, within the latex skin.
From here, flexible tubing (inserted into the metal duct) runs to a hole in the mouth area.
As a result, some fog exits the mouth, some fills the chest cavity.
This prop is wired so that the fogger and primary air cylinder are triggered simultaniously.
Considering the main lift is slowed down using cylinder port mounted flow controls, The fog begins
flowing from the prop slightly before the lifting motion begins.
As the lift progresses, the fog falling from the chest cavity helps to conceal the frame and linkage.
Front lighting the prop will add to this effect.
Mr. Spill was base coated an olive color. On that, mottle layers of ultramarine blue and napthol yellow bring some
ugly skin-like detail to the paint job. To blend the mottle layers, a translucent, very light blue was misted over everything,
heavier on the "underside" areas. Doing this blurred and/or lightened a lot of the detail in these areas.
His eyes and mouth were treated with gradations of blue, maroon, and black.
The entire eyeball was painted black, and the outline of the iris was painted a raw ocre color.
Some small vein details were added using the blue and maroon ... sparingly.
Some shadows that looked a little bland were accentuated with careful black shading.
He's finally painted and the finished colors are sealed with a matte finish.
Eyeballs, inner mouth, and teeth were then top coated with 5-minute epoxy for a wet look.
The evening weather is nice this time of year, and (indirect) sunset lighting is great for
non-flash photography. If I were skilled in this area, I'd have better pictures to show ...
Instead, here are a couple of video clips.
(In theory, if a picture is worth a thousand words, a video is worth downloading.)
Painted prop, testing, front view.
Painted Prop, testing with fog, corner view.
Black dreadlocks seemed like the right choice for this character.
He also has eyebrows, sideburns, and a fu man chu, but those details are mostly covered.
A crushed suede-type fabric was used for his hood. The extra weight of this material will hold its shape better.
Strips of Monk's Cloth were added as "sleeves". This fabric distresses very well, and takes color nicely.
A stretch fabric was added to his mid section. It provides adequate coverage, and will handle any abuse caused by leg movements
and contact with the linkage when the prop folds down.
All of his "clothes" were glued in place using contact cement.
This will keep him looking presentable even after numerous cycles.
A little exaggerated black shadowing with the air brush, and he's ready for action.