Complex Structural-Rating Analysis - Electro-Voice X-Line Very Compact Rigging Manual

3.4 Complex Structural-Rating Analysis

For a complete structural-rating analysis, the forces in each individual piece of attachment hard-
ware throughout the XLVC system must be determined, as well as the forces on each enclosure.
Determining these forces requires complex mathematical calculations. All of these forces must
then be compared to the working-load limits detailed below for each of the rigging points and the
overall enclosures.
The reader should consult an experienced structural engineer to perform the complex structural
analysis.
WHEN SUSPENDING ANY XLVC LOUDSPEAKER SYSTEM OVERHEAD, THE
WORKING-LOAD LIMITS MUST NEVER BE EXCEEDED FOR EACH INDIVIDUAL
RIGGING POINT, AND THE OVERALL ENCLOSURE.
XLD281, XLE181 and XS212 Front Rigging Structural-Strength Ratings
The working-load limit of each of the front rigging points on the XLVC enclosures is dependent
upon the hinge bar assembly, the rigging tube and channel assemblies, the enclosure and the
angle of pull. The structural-strength ratings for the front rigging points are identical for the
XLD281, XLE181, and XS212, and are shown in Figure 9. The enclosures have two rigging points
at the front. The structural ratings shown in Figure 9 are for a single rigging attachment point.
Each rigging point has the same rating.
The front-to-back structural-strength ratings for the front rigging points shown in Figure 9 cover a
full 360° rotation. Although it is not possible to put the front button bars into tension over 360°, it is
possible for the hinge bars to go into compression with some array configurations. Therefore, the
360° rating is necessary to accommodate both tension and compression. It also should be noted
that the XLVC front rigging is only rated for use over side-to-side pull angles of a maximum of
±10°.
XLD281, XLE181 and XS212 Rear Rigging Structural-Strength Ratings
The working-load limit of each of the rear rigging points on the XLVC enclosures is dependent
upon the swing arm assembly, the rigging frame assembly, the quick-release pins, the enclosure
and the angle of pull. The structural-strength ratings for the rear rigging points are identical for the
XLD281, XLE181, and XS212, and are shown in Figure 10. The enclosures have two rigging
points at the rear. The structural ratings shown in Figure 10 are for a single rigging attachment
point. Each rigging point has the same rating.
It should be noted that the front-to-back-angle range shown in Figure 10 for the XLD281 and
XLE181 consists of two 10° arc segments, while the front-to-back-angle range shown in Figure 10
for the XS212 consists of two 20° arc segments. When both the front and rear rigging are
installed, the front hinge bar always prevents the rear swing arm from having any kind of front-to-
back force. Thus, it will always be axially loaded. For the XLD281 and XLE181, a tensile force can
only be applied over an angle range of negative 0°-10°, while the XS212 can only be over a range
of negative 0°-20°. The angles are negative because the boxes can only be angled downward.
(Imagine two boxes facing straight ahead. The bottom enclosure can only be tilted downward
because the rear rigging can only be adjusted to bring the rear corners of the enclosures
together). It also should be noted that the XLVC rear rigging is only rated for use over side-to-side
pull angles of a maximum of ±5°.
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ELECTRO-VOICE X-Line Very Compact
TM
Rigging Manual