Daktronics DBH-150 - Manual (Page 11)

ADJUST & INSPECT BANNER HOIST
After installation under normal circumstances, users
should never have to physically move the hoist assembly
or open it up for maintenance. It may become necessary
though to open up the side casing and check the cables
on the drum should they begin to run over themselves.
If the upper and lower limits of travel need changing,
it is necessary to open the smaller side panel near the
receiver antenna to gain access to the rotary limit switch.
DBH-150 Limit Switch Operation & Adjustment
The limit switch assembly is comprised of a fully enclosed
4-switch rotary mechanism attached to the hoist drum
shaft with a flexible coupling. As the drum shaft turns,
the switch mechanism rotates cams in one direction or
the other to actuate snap action switches by depressing
roller levers attached to each switch.
The upper and lower limits, both normal and over-travel,
are set from the factory for the maximum travel of the
hoist. After installation, it may be necessary to reset
these limits based on the height of the installation and
the desired travel distance. The limit switch assembly is
shown in Figure 5 and is located under the left most
front panel of the hoist where the wireless receiver
antenna protrudes. Remove this panel to gain access to
the limit switch assembly. It will be necessary to remove
the yellow plastic cover to make the switch adjustments.
As shown on Figure 6, the Rotary Limit Switch is
comprised of a Lower Over-travel Limit Switch, a Lower
Normal Limit Switch, an Upper Normal Limit Switch,
and an Upper Over-travel Limit Switch. The limit switches
are activated when the white cam wheel rotates into the
roller lever on the limit switch.
Figure 5: Rotary Limit Switch
MAINTENANCE/INSPECTION
04
MAINTENANCE/INSPECTION
7
Figure 6: Rotary Limit Switch without cover
Lower Overtravel
Limit Switch
Lower Normal
Limit Switch
Upper Normal
Limit Switch
Upper Overtravel
Limit Switch