Theatre Design & Technology - Feb 1967 - 14

Demountability. In the permanent module the top, facing,
four sides of the pyramid, collar, strap, and two fasteners
constitute a total of ten individual parts. The six parts of
the pyramid can remain assembled in storage and nest
along with others. The two fasteners that secure the
fourth corner of the facing can be completely engaged or
disengaged by a 180 0 turn of a 5/8" open end wrench.
Total assembly of all 10 pieces may be accomplished in
less than five minutes with two people participating. If
the pyramid is taken from storage already assembled, one
person can complete the assembly in a minute and a half.
The disposable unit demounts into only four pieces since
the pyramid is collapsed rather than disassembled for
storage. The necessity of applying the dutchman to cover
and facing requires drying time.
Joining. Conventional joining by 3/8" carriage bolts is
impossible. The problem is solved here with a "Simmons" fastener called a "Roto-Iock." 7 It is counter-sunk
into the thickness edge of the 3 / 4" plywood cover or
will side mount on the underneath side. The fastener
locks with a 270 0 turn of a 5/16" allen wrench. "Rotolock No.1" will withstand load tension of 1400 Ibs. and
shear load of 2000 Ibs. This fastener will lock in seriously misaligned situations, so lack of precision in mounting
is no handicap. Its modest price at writing was 76 cents.
Maintenance and finished appearance of sub-structure.
There is no maintenance beyond repair of torn dutchmen
and replacement of splintered plywood covers.
By the very nature of its design the system cannot stand
unfaced.
Cost-economy. The disposable platform is very inexpensive. Many high school designers have found that local
construction firms are willing to lend full 4' x 8' sheets
so long as they are returned uncut. Such economy of
operation would provide a 4' x 4' x 18" platform at less
than $6.00.
The permanent model of the same size is slightly less
expensive than the comparable size standard parallel made
entirely from 3/4" plywood.
There is obviously no solution here to the vexing problem of adjustable height within a single module, nor can
the technician back a flat up to a Pyra-form and nail
them together for support. There are high and low effective limits to the system which require further testing.
However, 18" seems to be minimum and 48" a maximum for the disposable model. The permanent pyramid
will stand up at lower dimensions and the flex of the facing will not become a problem until heights above 72"
are reached. The recurrent use of 96" and taller platforms is slight in the limited experience of the writer and
the storage burden is more than a permanent structure
is worth. The braced-leg platform remains more effective
under the circumstances. The flex problem of the facing
on the permanent platform at 96" height could be solved
by reinforcement of the 1 /4" stock or by using heavier
stock for facing at these heights. The permanent model
may be caste red by adapting caster bracket (BR-2 marketed by Theatre Production Service, for instance) to
support slope of the internal pyramid.
The problem of an uneven stage floor is exaggerated
by the necessity for even contact between floor and facing along the entire plane. It is possible to cut a slight
arc from the bottom of each side of the pyramid and from
the bottom of each side of the facing to accommodate
some slight irregularity, but, a shim must be added at
the corners if the difference is much more than
1/4".
Otherwise considerable rocking and consequent squeaking
and creeping will occur.

Materials remain the primary obstacle to greater efficiency and broader application in this project. This is not
to say that adequate materials are not available, for they
are. But being processed and prefabricated for other industries, their qualities are too little known to us in the
theatre. And most technicians have too little time, and administrators too little interest in technical experimenting,
to attempt to adapt these existing materials to the needs
of the academic theatre. However, with increased enrollments, heavier teaching loads, rising production costs, and
the epidemic of expanded production schedules; cheaper,
faster, easier techniques must be forthcoming. Equally
important, these techniques and this information must receive wider circulation.

1 Only" Upson" of several brand names tested proved flexible enough
yet sturdy enough when scored and folded.
2 F.M.C. Corporation, 1617 Penna. Blvd .* Philadelphia 3, Pa.
3 Edmund Scientific Company, Newark, New Jersey, Catalog No. 661,
p.54.
4 Simmons Fastener Corp., North Broadway, Albany 1, N.Y., Catalog
No. 760, p. 40.
5 "Modular Platform Systems for the Stage," TD&T (December,
1965),9·13.
6 A.S. Gillette, Stage Scenery (New York: 1959). pp. 130-135.
7 Simmons Fastener Corp. Ibid., p. 25.
B Height dimension utilized in the formula must be minus the cover
thickness dimension. Facing height on disposable model must also
have subtracted the thickness of cover from finish height.
9 "POP" Hand Riveter complete with assorted rivets at $ 5.44. Also
available under Sears Roebuck trademark.

Construction I nstructions and Techniq ues
Dimensions
Using given height (h) and overhang (od) dimensions find
the diagonal dimension (dd) of the side of the truncated
pyramid as follows: B

Diagonal overhang dimension remains constant at 16 7/8"
for all heights. Begin with material 4' wide x dd long.
To find bottom horizontal dimension subtract four thicknesses of material from outside finish dimension:
3/16"x4 = 3/4,48"-3/4= 47 1/4for4'x4'
disposable model. To find top horizontal dimension scribe
a vertical centerline (23-5/8" from either bottom corner)
from bottom up. Measure one foot along the top in both
directions. These points form the top right and left
SCORE corners. For the disposable model scribe a SCORE
line diagonally from the bottom corners to the top SCORE
corners forming a trapezoid. Measure one inch outside
this SCORE line on each side and cut. For the permanent
model, above mentioned SCORE line becomes the cut
line. (See figure 1)

I]ill[] THEATRE DESIGN AND TECHNOLOGY

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