problems involved the
wedge jamming in the
downwards position
and high-centering the
robot. Following this
experimentation, the
design was applied to
our successful beetle
Cloud of Suspicion’s
first two revisions, as
well as the third
version of Gilbert. It proved effective
time and time again against
weaponless bots and spinners alike,
and I actually wrote an article for
SERVO about the design over a year
ago. Unfortunately, as we began to
travel and compete with more
effective bots such as the Fierce
robot fleet and many east coast
spinners, wedgectomies became a
steadily increasing occurrence. After
having Gilbert’s wedge torn off and
the top carbon fiber subsequently
destroyed along with an even more
caustic but successful fight with
Cloud of Suspicion against the
under-cutter Itsa?, I finally decided
that it was time for something new.
The first thought that came to
mind was to replicate the similar
hinged wedge system used on our
featherweight, Pinball. Pinball’s
wedge differed from most of ours at
the time in that the steel wedge
itself is welded directly to the shaft
which sits loose in an oversized hole
made in each of the 1” thick UHMW
side pieces. An initial problem we
encountered with Pinball’s wedge
design was that the shaft could be
torn through the UHMW if pulled
hard enough by a vertical spinner.
This was later fixed by welding
together a .125” 4130 steel bracket
that completely covered the
extrusion, leaving a hole for
the shaft to ride in.
I likely would have gone
this route if not for a fight with
a horizontal spinner that left
Cloud of Suspicion’s aluminum
wedge support extrusion
lopped off. With all this in
FIGURE 4. MH Robotics’ fairyweight,
FIGURE 2. The third revision of Cloud of Suspicion,
sporting our most recent wedge design.
FIGURE 3. Featherweight
Pinball, showing its shock
mounted steel flat plate.
mind, I chose to follow Mike Daniel’s
advice and draw up an all new
hinged wedge design mildly based
off of his old 30 lber, Doom.
The initial problem I wanted to
address was how most hinged
wedges rely on one or several
mounting points based on a flat
axis. I chose to combat this (no pun
intended) by designing a right angle
clamp that holds the shaft down on
two perpendicular axis. This makes
the entire assembly much more solid
and the clamps themselves are
nearly impossible to tear off, even
though they’re being held in
through machine screws to the soft
UHMW. Of course, to maintain the
idea of riding the design of singular
plane mounting areas, I chose to
have the wedge welded to the shaft.
Initially, I planned on an .09”
titanium wedge for Cloud of
Suspicion and .075” for Gilbert, but
the deal fell through.
Fortunately, we were able to go
through with the design by using
4130 chromoly steel for the wedges,
shafts, and even the clamps which
would eventually be hardened for an
even stronger assembly. The live
shaft sat loose in a slot cut into the
top corner of the UHMW, and was
kept from falling loose through the
several clamps. The only downside
to this durable and complex
assembly is in how many pieces and
separate cuts, bends, and welds it
entails. However, in the many fights
that it’s been through thus far on
Gilbert and Cloud of Suspicion, it
has proven much more durable by
far than the previous design.
FIGURE 5. The current Gilbert’s main attachments,
including the hinged wedge, wedge-plow, and
steel flat plate.
SERVO 07.2010 29