DE-STA-CO 722 INTERMITTOR - Manual (Page 28)

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SECTION 9: THINGS TO AVOID
An Industrial Motion Control Indexer is a relatively simple mechanism using an input shaft
mounted cam to drive roller followers on the output hub. While simple in concept, the precision
nature of the indexer requires that it must be used within design constraints. The indexer is, after
all, just a mechanical device. In this regard there are several situations which should be avoided
to protect your warranty and maximize indexer life.
Off-center loading, such as might be seen when a large press is used in conjunction with
an indexer, requires a back-up support anvil under the dial. The bearings of an indexer are
very heavy duty, but their life will be shortened dramatically by unsupported, asymmetrical
loading. The support anvil is typically designed with .001” of clearance under the dial and is
strong enough to carry the full load of the asymmetrical load. Consult Industrial Motion
Control Technical Sales Department at 1-800-645-5207 or 847-459-5200 for assistance in all
asymmetrical load situations.
E-Stop Usage should be limited to emergency situations only. E-Stops should not be used
to jog an indexer. The E-Stop function causes extreme load conditions inside the indexer by
virtue of the instantaneous stopping of significant weights. This is not unlike driving a car
into a brick wall. Excessive use of the E-Stop will significantly shorten the life of the indexer.
Starting and Stopping while in the motion profile of the cam will also put high loading
on the indexer’s internal components. Should it be necessary to stop/start the indexer in
any position other than the dwell of the cam, it is best to reduce motor speed to avoid
overloading the unit.
Shock Loading may also lead to problems. Shock loading typically occurs when there is
looseness in the input drive train or where the output load is not stable.
This condition will eventually damage either the indexer’s followers or cam. Overload
devices, that are not set correctly, are sometimes a source of this condition. Chain drives or
loose timing belt drives are also potentials.
Machine Jams, like E-Stops, put excessive loading on an indexer. While the impact of jams
is minimized by the use of overload devices, it is always best to track the occurrence of jams
and, when possible, rectify the condition that led to the jam.
A high jam frequency will shorten indexer life.
Friction from any source adds to the load of an indexer. This can include cam driven
mechanisms and/or additional, ancillary devices driven off the indexer’s drive shaft or output.
Extreme build-up of contamination or other sources of interference adds to the frictional load.
Ferguson indexers handle frictional loads very well, but the loading must be evaluated in terms
of the indexer’s overall capacity to ensure that the life of the equipment will not be compromised.
IMPROPER LUBRICATION CAN RESULT IN IMMEDIATE CATASTROPHIC FAILURE
OF THE UNIT.
Contact Industrial Motion Control Technical Sales Department (1-800-645-5207 or
847-459-5200) or your local Sales Engineer for assistance when evaluating the
above conditions.