A “Toolbox” for Forensic Engineers

404 Forensic Materials Engineering: Case Studies
Flanged monocoque
mower
Flanged platform
mower
A A
B
B
Figure 13.13 Stage 2 of development of flanged monocoque lawnmower.
molding cycle. This means that reentrant angles cannot be used in
the shell design. So how is the monocoque divided? The various
options are shown in Figure 13.13, Figure 6, by two possible dividing
lines. Option AA is feasible while BB is not because of the reentrant
properties of the external flange. A gate situated in the center of each
part would represent the best design solution.
9. Option AA gives the model shown in Figure 13.14; stage 3 (top),
which itself could be further modified by moving the bond line so
that the external flange is incorporated into the shell, as shown in the
lower part of the figure. In the opinion of the independent expert,
this design option would have been obvious to any designer working
before the priority date of the B&D patent.
As is the practice in all actions, the expert evidence was exchanged before
trial so that both sides could see what arguments would need to be developed
and explored. The expert for Black & Decker, a distinguished design engineer,
generally supported a wide interpretation of the patent-in-suit with the two
Flymo mowers indeed infringing claim 1 (and probably other claims as well).
As is also common in many patent actions, the parties did not meet to discuss
their positions, and focus on the points of agreement and disagreement. It