Specifications

18 U-5 IOM
Procedure for belt tensioning
Instructions
Set tension of new drives at the maximum deflection
force recommended. Check tension at least twice
during the first day of operation, since there will
normally be a rapid decrease in belt tension until
belts have run in. Check tension periodically after the
first day of operation and keep tension in
recommended range. The correct operating tension
for a V-belt drive is the lowest tension at which the
belts will not slip under peak load conditions. Shafts
must be adequate for the tensions required.
To determine lbs. force required to tension a drive
with belt tensioner, do the following:
1. Measure belt span as shown (Figure 11).
2. Divide belt span by 64 to get belt deflection.
3. Set large “O” ring on “span scale” at required belt
deflection. This scale is in
1
⁄16 inch (1.6 mm)
increments.
4. Set small “O” ring at zero on “force scale”
(plunger).
5. Place larger end of tension tool squarely on one
belt at center of belt span. Apply force on plunger
until the bottom of the large “O” ring is even with
the top of the next belt or with the bottom of a
straightedge laid across the sheaves.
BELT SPAN
DEFLECTION =
BELT SPAN
64
Figure 11. Belt deflection
Table 1. Super Gripbelts
Figure 12.
Small
"O" Ring
Large
"O" Ring
SPAN SCALE
FORCE SCALE
Belt Tension
Checker
6. Read force scale under the small “O” ring to
determine the force required to give the needed
deflection
7. Compare the force scale reading with the correct
value for the belt style and cross section used as
given in Table 1. The force should be between the
minimum and maximum values shown.
8. If there is too little deflection force, tighten belts. If
there is too much deflection force, loosen belts.
Example
1. Belt span is 64 inches (152 cm). Small sleeve has
a 6-inch (152 mm) pitch diameter with “B” Super
Gripbelts.
2. Sixty-four inch ÷ 64 = 1 inch (25 mm) deflection
needed.
3. Set large “O” ring at 1 inch (25 mm) on span
scale.
4. Set small “O” ring at zero plunger.
5. Press down on plunger until bottom of large “O”
ring is even with top of next belt in set, or with
bottom of a straightedge.
6. Check lbs. force required for a 1-inch (25 mm)
deflection of belt.
7. Super Gripbelt table (below) shows a “B” belt used
with 6-inch (152 mm) pitch diameter. Small sheave
should have a deflection force between 6 lbs. 6
oz. (2.89 kg) and 8 lbs. 8 oz. (3.97 kg).
8. Increase or decrease tension on belts until
deflection force lies in the required range.
BELT CROSS SMALLEST
RPM
DEFLECTION FORCE (LBS.)
SECTION SHEAVE
SUPER GRIPBELTS GRIPNOTCH BELTS
UNNOTCHED BRANDS NOTCHED BRANDS
4.4 – 5.6
860 – 2500 5.3 7.9 7.1 10.5
2501 – 4000 4.5 6.7 7.1 9.1
B, BX
5.5 – 8.6
860 – 2501 6.3 9.4 8.5 12.6
2501 – 4001 6.0 8.9 7.3 11.9