13
Recommended Output Configuration
The objective of a good output connection to an Index Drive is to make torque levels predictable and
limited in magnitude. A good connection is rigid and free of backlash.
DESTACO recommends that a CAMCO output overload clutch be used with index drives whenever
possible. This will prevent costly damage to the unit in the event of a jam and eliminate costly down
time.
Our preference for output connections is as follows and in this order:
1.
Flange mountings are superior
. A properly bolted and dowelled connection will provide a good
connection for dials, sprockets, gears and overload clutches. DESTACO provides output flanges
on most CAMCO indexers for this reason.
2.
Zero backlash or rigid
couplings
are suitable, especially with tapered bushing. During
installation, special care is required to assure alignment of the coupling. When selecting a
coupling a high service factor must be used. Brands available are Thomas Coupling, Rexnord,
Zurn Industries, etc. Some customers have been successful with rigid couplings, but alignment of
shaft becomes critical. Shaft failures are common in these situations.
3.
Timing belt drives
if sized properly are an excellent drive. Unfortunately, proper sized means
large and thus can seldom be used on higher speed applications. The timing belt drive tends to
use up a significant amount of available index drive capacity.
4.
Gears and chains are not very desirable
and should be used only if no other method is possible.
Gears should be set to minimum backlash and maximized in size. Unless enclosed and oil
lubricated, only slow speeds are acceptable. Chains stretch and have backlash. Again, a larger
sprocket size helps and some customers have been successful with self-adjusting idler
arrangements.
CAUTION: Torsional windup in line shafting is just as undesirable as backlash. Long slender line
shafts, rubber insert couplings, long belts and spongy mountings will drastically increase actual torque
demand which in turn raises torsional windup. Breakage or severe vibration may result.
5. For the calculations on any Indexer or Oscillator drive application to be of any value, both the
input and output connections must be "stiff" and free of backlash. This is as important as the sizing
of the Index Drive itself.
