Appeal No. 1998-2179 Page 4
Application No. 08/433,231
operator and spread into a rough shingle and conveyed to a holding location 15 and a second
conveyor (belt B4) for periodically stripping off successive signatures from the holding location
to form a uniform shingle which is transported at high speed to a processor. A barrier or stop
means comprising stop tubes 85 carrying flat plates 85a are located at the holding location 15
such that signatures of the rough shingle flowing inwardly will have their leading edges strike
the plates, thereupon to fall vertically downward so as to create a vertical queue stack 16. The
second conveyor comprises a belt B4 having a plurality of rows of holes 105 spaced a distance
S apart. A vacuum chamber 110 having vacuum slots 106 in the top surface thereof is located
beneath the belt B4 such that, when the holes 105 of the belt B4 are aligned with the slots 106,
air is sucked downwardly through the belt. The weight of the vertical queue stack is controlled
and limited so that until a row of holes 105 reaches the vacuum slots 106, the belt B4 may slide
or slip relative to the lowest non-moving signature in the queue stack. As a result, a given
signature at the bottom of the queue stack is not moved forwardly with the belt when the
preceding signature begins to move. Rather, that given signature remains stationary until such
time as the preceding signature has moved a distance equal to the spacing S between the
successive rows of holes. Thus, successive signatures are started seriatim and pushed
forwardly through the gate beneath the tips 85b of the tubes 85 with the leading edge of each
signature trailing that of the preceding signature by a shingle setback SSB equal to the spacing
S (column 9, lines 40-56 and Figures 10 and 11).
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