Theatre Design & Technology - Summer 2017 - Public - 63

Improved Wagon Brake
By Shannon Perry and Tim Francis
Trinity University

or a recent production of The Three Sisters at
Trinity University, the set design included a large
wagon unit moved to different positions on the
stage for each act. Because of a vista scene changes,
foot irons and stage screws were not practical. We
considered using four heavy-duty wagon brakes, but
were concerned that they would not provide enough
stability because of the limited stage floor contact area.
We developed an improved brake that makes contact
with a larger surface on the stage, thereby stabilizing
the wagon more effectively.
To create one improved wagon brake, we began
with two 800-pounds holding capacity push-pull toggle clamps (Clamp-Rite 13100CR) purchased on Amazon.com. These were spaced 6" apart center to center,
and the mounting plates of both clamps were welded
to a single piece of ¼"x 3"x9" plate steel (Figure 1). To
allow us to attach the brake to the platform, we drilled
through the existing bolt holes of the clamp mounting plates through the plate steel. In another plate of
the same size, we drilled two ⅜" holes 6" inches apart.
We passed two ⅜" hex head bolts through these holes,
loosely affixed them in place with nuts, and threaded
these bolts into the two welded toggle clamps. We
chose not to weld the bolts directly to the steel plate
because we wanted to allow for potential adjustment.
If the nuts attaching the bolts to the plate are loosened,
the bolts can thread into or out of the clamp, allowing
the plate to adjust up or down as needed.
The vinyl grips were removed and a length of ¾"
steel square tube was welded between the clamp levers to create a handle, making it easier to deploy the
brake in one. Then, because the exposed bolt heads
underneath the plate caused the plate to sit above the
ground, we drilled two holes through a piece of ½"
plywood that were large enough to accommodate a
9/16" socket. We attached this plywood to the bottom
of the plate using double-sided carpet tape (Figure 2),
thereby ensuring that the entire surface area of the
plate would make full contact with the stage without
being impeded by the bolt heads. The bolts could now
be loosened or tightened using a socket through the
hole in the plywood.
Ultimately, we have found that the increased surface area from one improved wagon brake yields far
greater contact with the ground than the base of a
standard toggle clamp. The adjustability of the design
has proved useful because the brake can be placed at

Figure 1

Figure 2

any height on the edge of a platform, and can still be adjusted to solidly lock to the ground. At a cost of around
$40, we have found this design to be a simple solution
to the problem of stabilizing wagons effectively.
S u m m e r 2 0 1 7

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