Installation manual

Community S-Series - Operation and Installation Manual - Page 45
only 30% of its rated strength. At 90º it is de-rated to only 25%. Use at angles steeper
than 45° is strongly discouraged. Such use would be permissible for breasting back a
loudspeaker to alter its downward angle, where the breast line is not part of the suspension
system nor is it considered to be the safety cable. Vertically rigging a loudspeaker from
eyebolts placed into its side surfaces (90º) must always be avoided. When eyebolts must
be angularly loaded, it’s vitally important to design any multi-point suspension installation
with a low bridle angle (see Load Angles), and to de-rate the eyebolt accordingly.
Proper Tightening of Eyebolts
If the shoulder eyebolt is not properly tightened, its angular load bearing ability will
significantly decrease, leading to rapid failure. Make sure to follow the eyebolt
manufacturer’s instructions for proper tightening. The prudent installer will be prepared in
advance, carrying a calibrated torque-wrench in the toolbox and a way of coupling it to the
eyebolt. We recommend cutting a groove into the sides of a large socket, as a means of
using the torque-wrench to tighten the eyebolt.
Eyebolt Orientation
A shoulder eyebolt should only be angularly loaded in the long axis of the loop of the eye; it
should never be laterally loaded. Loading against the axis of the eye can cause breakage at
even very low force. After tightening the eyebolt, if the eye is not aligned axially to the
line-of-force, a shim or washer should be installed to re-position the eye. The eyebolt
should never be loosened or over-tightened as a way of aligning its axial orientation. If
you’re equipped in advance with a variety of washers and shim material, you’ll be able to
safely install eyebolts quickly and painlessly.
Lastly, never reeve slings in a basket-type hitch through eyebolts (see Figure 14 below).
Doing so will radically increase the strain on the eyebolts and on the slings from vector
loading, as well as permitting the load to tip or shift.
Figure 14: Never Reeve Cables!
9. Threaded Fasteners
Threaded fasteners are often used in rigging and mounting systems. As with eyebolts,
many of Community’s optional mounting brackets, yokes, and rigging plates utilize
threaded fasteners. The fasteners that come with each Community rigging kit are load
rated to a sufficient strength to be safe when used within their specified parameters. If
replacement bolts are needed, or if additional bolts are required for mounting a bracket to a
beam, wall, or ceiling etc., such bolts should be purchased from a reputable manufacturer
with a minimum Grade 5 rating. On hex-head bolts this can be readily identified by looking
at the head. A Grade 5 bolt will be marked with three lines; a Grade 8 bolt, which is even
stronger, with six lines. Allen drive fasteners are often made of high-strength steel (Grade
5 or better) if they are purchased from an industrial suppler. As with any other rigging
component, check the rating on the box or the manufacturer’s specification sheet to be
sure.