Service manual

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 lub-

ricated, 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 again 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.

6. Permanent magnet motors fulfill two objectives, low cost and low inertia, but are at a disadvan

tage

for flywheel energy. This is especially serious for large dial and reciprocating applications. CAMCO

does not recommend operating permanent magnet motors below 1000RPM, and if loads are

very

heavy we would like to see 1500RPM or more. Failure to maintain these minimum speeds will

result

in erratic input speeds and unpredictable torque levels.

7. Air and hydraulic motors can cause considerable problems. The inherent low inertia of these motors

and the resulting lack of adequate stored flywheel energy do not provide a reliable constant input

velocity.

RECOMMENDED OUPUT 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 free of backlash and rigid.

CAMCO 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-up 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 con-

nection for dials, sprockets, gears and overload clutches. CAMCO provides output flanges on most

CAMCO indexers for this reason.

2. Zero backlash 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.