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facts about gates
powerband® belts
What is PowerBand®?
The Gates PowerBand Belt is made up of two or
more strands (standard cross section V-belts) banded
together at the top with a tieband. The strands and
the tieband are vulcanized together, forming
one homogenous belt.
Tie Band
Construction
Flex-Bonded
Cords
Concave
Sidewalls
Hi-Power II Construction
The cross section and spacing of the individual
strands are such that the PowerBand belt operates
on standard sheaves. No special sheaves are
required.
The tieband clears the top of the sheave so that each
strand has full wedging in the groove, just as though
it were a single belt. Therefore, the PowerBand belt
operates at the same low tensions as do individual
belts on an ordinary V-belt drive.
Types Available:
Gates Super HC® Molded Notch PowerBand Belts
Gates Super HC PowerBand Belts
Gates Hi-Power® II PowerBand Belts
Predator® PowerBand Belts
Engineering Reasons for
Using PowerBand
Most V-belt drives operate without trouble, requiring
only routine maintenance. However, there are cases
where forces acting on the drive can cause belts to
whip and turn over or come off the drive. Gates
research engineers designed and developed the
PowerBand belt to solve these belt stability problems.
Such stability problems are most frequently caused
by continuous, pulsating loads on a drive, or by shock
loads. Less frequent causes are prior belt damage,
foreign material entering the drive or mechanical
deficiencies such as misalignment of dynamic
unbalance.
Internal combustion engines, air compressors, piston
pumps and many other types of driveR or driveN
equipment impose a periodic load variation on a
drive. This variation causes a continual fluctuation in
belt tension on both the tightside and slacksides of
the drive. If the magnitude of the tension fluctuations
is great enough to overcome the natural damping,
and the frequency of the fluctuations corresponds
with the natural frequency of span vibration for the
belts, belt vibration can reach high amplitudes.
If the belt vibration is vertical to the groove so that the
belt always enters the sheave in a straight line, the
belt vibration does not cause turnover. Most vibrating
belts exhibit lateral (sidewise) motion also, and this
causes the belt to enter the sheave groove
misaligned. The belt either turns over, or is thrown
completely off the drive, often taking the other belts
with it. Shock loads have the same end effect, even
though they may occur at random rather than being
continually present.
If lateral vibration of the belt can be prevented,
stability problems can be eliminated. You have
probably seen flat belts operating under pulsating
loads. They vibrate vertically, but there usually is no
lateral vibration. This is because the belt is extremely
stiff in the lateral direction, but quite flexible in the
direction of normal bending. The high
degree of lateral rigidity prevents lateral vibration. For
individual V-belts, the ratio of lateral to vertical rigidity
is much less than for a wide flat belt. That is, they can
bend sidewise much more easily and can vibrate
laterally almost as easily as they can vibrate
vertically.
Joining the V-belts together into a PowerBand
belt increases the lateral rigidity by many times. It
becomes very difficult to bend the belt sidewise
and lateral vibration is eliminated. The individual
strands in the PowerBand belt always enter the
sheave grooves in line, and turnover or throwing of
belts is eliminated.
When To Use PowerBand
Belts
Gates PowerBand belts are useful for solving
problems on existing equipment or as insurance in
preventing problems on new equipment.
Pulsating or Shock Loads—PowerBand belt prevents
belts from turning over or jumping off the drive.
Clutching Drives—PowerBand belt allows each
strand to pick up its share of the load at the same
time, resulting in smooth, trouble-free operation of
drives which use the belts as a clutch.
Individual Belt—PowerBand belt allows you to gain
all of the advantages of multiple V-belt drives, while
at the same time using only one belt in cases where
this is desirable.
V-Flat Drives—PowerBand belt has superior ability to
stay on the flat pulley of a V-Flat drive
Gates Corporation 1 1551 Wewatta Street 1 Denver, CO 80202