Chamberlain BG790 - Manual (Page 15)

Installation
15
Doc 01-G0674
Rev E
BG790: WISHBONE COUNTERWEIGHTED ARM
Attach left and right arms to the arm hub flanges
as shown and described below.
1 Bolt counterweights to ends of arms clamps
as shown. Use Caution lifting 57lb. weights.
2 Bend and fasten the two arms together as
shown in Figure 10.
If an extension arm is required, sandwich
the extension arm between the two halves
of the wishbone arm before bolting together.
See Arm Fabrication starting on page 12
for extension arm preparation.
3 Assemble the two 3/8" threaded rods to the
arms for center support as shown in Figure
10.
4 Turn on power and test the gate.
Wishbone Arm - Arc of Travel
Ensure adequate clearance for travel of arm.
01-G0674F11
Figure 9
WARNING
Be prepared for gate to start when you turn the power on.
01-G0674F12
(4) 1/2-13 x 2 1/4”
Bolts
(4) 1/2” Flatwashers
(4) 1/2” Lockwashers
(4) 1/2” - 13 Hex Nuts
Wishbone
Arm
Figure 10