26
Installing an Extension Arm
Some gate installations do not meet the geometrical
constraints shown in Figure 2. In those situations, the
750 Extension Arm option can be used along with the
750 drive unit, power unit, and control panel to install
an unobtrusive gate operator.
Using the 750 Extension Arm means that you do not
have to permanently remove any leaf hinges, the gate
leaf does not need to form a 90-deg angle on the bottom
corner nearest the gate post, and the relative location of
the rotation axis is not so restricted.
The geometrical constraint for using the 750 Extension
Arm is that the center of the splined shaft on the drive
unit
must
be within 6 in. (15.25 cm) of the axis of
rotation of the gate leaf.
WARNING!
The farther away the splined
shaft is from the gate's axis of rotation, the
greater the risk of danger from pinch points.
Install the drive unit so that the splined shaft is as near
as possible to the gate's rotation axis and is directly
beneath the center of the fully closed gate leaf.
You need to position the extension collar (see Figure
23) so that it smoothly slides within the extension U
from the fully closed to the fully opened position. Note
that the position of the extension collar is affected by
the overlap of the extension bar and extension U.
Attach the 750 extension collar to the bottom of the gate
leaf with a 7/16 in. (1.1 cm) bolt.
Weld together the extension bar and extension U
according to Figure 23.
Caution:
Do not weld anything to or on the
inside of the sleeve of the splined shaft.
Next, weld the outside of the sleeve for the splined shaft
solidly to the inside of the hole in the end of the
extension bar.
Follow the rest of the instructions for installing the 750
Operator. With an extension arm, you need not worry
about installing a gate leaf shoe nor about installing the
gate leaf in the shoe. Instead, you will install one end of
the welded extension arm over the splined shaft and the
other end around the extension collar.
In addition, you will need to provide a washer beneath
the extension collar to keep the extension U from falling
off the collar. You also need to shield any pinch points
around the extension arm.
(b)
(a)
Minimum overlap of
2 1/2 in. (6.4 cm)
750 extension
bar
750 extension U
750 extension
collar is attached
to the bottom of
the gate leaf
Extension bar
Minimum overlap of
2 1/2 in. ( 6.4 cm)
Extension U
Extension
collar slides
within
extension U
Hole in the extension bar fits around and
is welded to the outside of the sleeve of
the splined shaft
Bottom of
gate leaf
Figure 23. The 750 Extension Arm, (a) side view and (b) top view
