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Bulletin: SVB-105
Date Issued: April 2, 2004
Category: Assembly
Subject: Lift Assembly Double Chain Sprocket Inspection
Machine Models: All TEI Jumbo Bottom Feeders and Jumbo Top
Feeders from P4200 to P10840
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Problem:
An operator of a Jumbo Bottom Feeder recently
reported finding unexpected structural damage that required
significant unscheduled machine downtime to repair. No indications
of an impending problem were evident until maintenance personnel
observed that a visible hole was developing in the side of the
prefeeder structural frame. This prefeeder had been in regular
service for approximately 3 years and operated normally.
Inspection of the lift assembly chain and
double sprocket assembly on the operator side found that the double
sprocket had moved outboard on its shaft, contacting the inside of
the prefeeder frame. This action resulted in extensive contact
damage to both the double sprocket and the frame. Maintenance
personnel replaced the sprocket, bearings, and shaft and performed
weld repairs to restore the integrity of the prefeeder frame.
Inspection of the lift assembly chain and
double sprocket on the drive side found that the double sprocket on
that side had also moved outboard by several inches but had not yet
contacted the prefeeder frame; thus no damage had yet occurred.
Maintenance personnel moved the sprocket back into the center
position on the shaft and re-torqued the fasteners that secure the
taper-lock bushings and double sprocket in the original position
relative to the shaft.
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Recommended Action:
Alliance recommends that you perform an initial
inspection as described below within 90 days after receipt of this
service bulletin.
In addition, Alliance recommends that you
perform a repeat inspection at annual intervals if the permanent
spacer repair per step 4 is not accomplished.
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Procedure:
-
De-energize and lock out the machine as
described in the Operators Manual.
-
Inspect the lift assembly chain double sprocket
on both the operator side and the drive side for any evidence of
sliding movement on the shaft. The sprocket is normally positioned
on the shaft as indicated in Fig 1.
-
If any relative movement is found, loosen the
taper-lock bushing setscrews, re-position the double sprocket on the
shaft, and tighten setscrews to 800 in-lbs. Refer to the attached
Martin Taper Bushings instruction sheet. Use of Lock-tite on the
setscrews is recommended.
-
As a permanent repair operators can fabricate
and install spacers on the shaft on both sides of the sprocket to
prevent movement. Alliance can provide further details for spacer
fabrication if prefeeder P# and shaft diameter are provided to
Alliance.
Note: If the permanent repair is installed
there is no need to perform any repeat inspections as recommended
above.
- Remove lock-outs and check for proper machine
operation per the Operator’s Manual prior to resuming production.
Please advise Alliance of any significant
findings resulting from your inspections. Comments may be forwarded
to Mr. Mike Thayer, Customer Service Manager, at
mthayer@alliancellc.net.
Figure 1: Double Sprocket Configuration
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