User's Manual

16 LS420 Universal User Manual V2.91 2003-01-21.doc
2.4 Anti-two-block switch installation V2.0
To ensure reliable radio communication between the sensor (anti-two-block switch) and
the display unit the sensor must be placed such that its antenna is not in contact with
metal and has a direct, clear line of sight to the display unit antenna. Mount the sensor
on the same side of the boom as the operator's cab.
Before mounting any anti-two-block switch, verify that it is calibrated to the display unit. All
switches shipped with display units are pre-calibrated in the factory. The display unit should go
into alarm when the wire rope of a calibrated switch is pulled and released. Please note that the
black travel clip must be removed to permit the switch to function. If a switch does not appear
correctly calibrated to the display unit please follow the instructions in the calibration section
(chapter 5) of this manual.
Step 1) Remove the black travel clip.
• Leave the black travel clip at-
tached to the sensor by the thin
wire: it will be useful if the sensor is
to be removed and stored in the fu-
ture.
• Releasing the wire rope will
cause the alarm buzzer of the dis-
play to which it is calibrated to
sound. Pressing the bypass button
of the display will silence the buzzer
until the next two-block event or
simulation.
Step 2) Position the sensor mounting bracket.
To ensure that the sensor can pivot securely on the mounting
bracket throughout the full range of boom angle, the mounting
bracket must be positioned at a 30° from horizontal with the
boom parallel to the ground and such that the locking pin of the
mounting bracket points up. Bolt or weld securely.
a) A2B switch placement on a telescopic crane.
For both live end and dead end mounting:
Up to 8”
diameter
Mount bracket
below
and
behind sheave center (see
shaded region of diagram).
Depress the small button to
release the locking mechanism
and simultaneously…
…slide the locking ring back.
The clip can now be opened
to release the wire rope.
Pin up
30
°
from
horizontal