Installation Instructions
Although each Door Operator has been fully inspected and tested prior to shipment, assure that no
physical damage has occurred during shipping and handling.
Premature failure
may occur if any part of
the installation is not done properly.
1. To install the
NB-4120-1 Double Belt
refer to
NB-4120-1M
.
2. Install the
Left Door Attachment (upper/outer belt)
and
Right Door Attachments (lower/inner
belt)
as indicated on drawing
NB-4120-1P.
Assure the belt centerlines are parallel with the track
centerlines (shim as required) within (+/-) 1/16” over track length.
3. Before mounting the
Take-Up Frame
, use a string or the timing belt to check the belt centerline
from the door attachments to each pulley centerline on the Take-Up Frame. Minor adjustment can
be made by loosening the shaft collars and moving the take-up shaft from side to side. Install
Take-Up Frame
per
NB-4120-1B
.
4. Before mounting the
Gear Motor Bracket
, use a string or the timing belt to check the belt centerline
from the door attachments to each pulley centerline on the Gear Motor Bracket. Minor adjustment
can be made by loosening the shaft collars and moving the Gear Motor shaft from side to side.
Install the
Gear Motor Bracket
as shown on drawings
NB-4120-1M
and
NB-4120-1D.
5. Verify the
Take-up End Pulleys
are adjusted in the direction toward the
Gear Motor Pulleys
as
much as possible by backing off the threaded rod.
6. Assure both doors are in the closed position before attaching the side of the H x 2.0” timing belt
marked
“Take-Up Side/Right Door”
to the
Right Door Attachment (lower/inner belt)
closest to
the take-up side. Secure the belt with (1) of the
Clamp Plates
and the mounting hardware supplied
per
NB-4120-1P
, making sure to tighten the (4) mounting bolts with an alternating sequence in
order to equalize the clamping pressure.
7. Taking out the slack, pull the
Take-Up Side
of the belt around the
Take-Up Pulley
and work toward
the
Gear Motor End
. Use a C-clamp to temporarily secure the belt to the
Take-Up Pulley
.
8. Pull the belt around the
Gear Motor Pulley
taking out all the slack. Use another C-Clamp to
temporarily secure the belt to the Gear Motor Pulley.
9. Attach the other side of the H x 2.0” timing belt marked
“Gear Motor Side/Right Door”
to the
Right Door Attachment
(lower/inner belt)
closest to the Gear Motor End. Secure the belt as
described in Step 6.
10. Remove the C-clamps attached to the Take-Up Pulley and Gear Motor Pulley.
11. Assure the belt teeth are fully engaged into their respective pulleys. Adjust the take-up end
threaded rods as required. Adjust the Gear Motor End by shimming (shim pack included) the
bracket at the mounting surface.
12.
Pre-Tension
the belt enough to move the Right Side door to the open position by tightening the
take-up end adjusting rods in an alternating fashion.
13. Move the Right Side Door to the open position manually by using a chain wrench on the shaft
collars. (a wrench with sufficient leverage is required) on the Gear Motor Output shaft. If you prefer
to move the door to the open position under power at very low speed, skip to step 16 then go back
to step 14
14. After the door has been moved to the full open position, the timing belt can be adjusted for
full Pre-
Tension
. The correct
Pre-Tension
in the belt has been set when measuring the force (F) to deflect
the belt 1.0” at mid-span per the formula in Parameters Section.
15. While the Belt Idler has been pre-set to tension the slack side of the Gear Motor Pulley at the
factory, it is recommended that the Pre-Tension on the Belt Idler be checked by the same method
as in Step 14 and adjusted if required.
