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B-LOC
®
Shrink Discs provide a high capacity, zero-backlash shaft/hub or coupling
connection by means of a mechanical interference fit. Please follow these
INSTALLATION AND REMOVAL INSTRUCTIONS carefully to ensure proper
performance of this
B-LOC
®
unit.
WARNING
When installing or removing
B-LOC
®
products, always adhere to the following
safety standards:
1. Be sure that the system is de-energized using proper lockout/tagout
procedures.
2. Wear proper personal protective equipment.
Figure 1
BEFORE
AFTER
INSTALLATION
(Refer to Figure 1)
B-LOC
®
SD40 Shrink Discs are supplied ready for installation. Therefore do not
disassemble the unit.
Important: Never tighten locking screws before shaft installation, as inner
ring of Shrink Disc and/or hub can be permanently contracted
even at relatively low tightening torques.
1. Clean hub O.D. and Shrink Disc bore. Lightly lubricate hub O.D. using ordinary
machine oil before assembling Shrink Disc on hub.
2. Carefully clean shaft and hub bore of any lubricant using a non-petroleum-
based solvent prior to mounting hub onto shaft.
This step is critical, as any
lubricant on the shaft/hub bore interface will greatly reduce the torque
transmitting capacity of a B-LOC
®
SD40 Shrink Disc connection.
3. After confirming correct position of hub and Shrink Disc, hand-tighten three
(3) or four (4) equally spaced locking screws making sure that inner and
outer ring are parallel. Hand-tighten remaining locking screws.
INSTALLATION WITH A TORQUE WRENCH
4. Use torque wrench and set it approximately 5% higher than specified
tightening torque (Ma). Tighten locking screws in either a clockwise or
counterclockwise sequence, using approx. 1/4 (i.e., 90°) turns (even if initially
some locking screws require a very low tightening torque to achieve 1/4 turns)
for several passes until 1/4 turns can no longer be achieved.
5. Continue to apply overtorque for 1 to 2 more passes. This is required to
compensate for a system-related relaxation of locking screws since tightening
of a given screw will always relax adjacent screws. Without over torquing,
an infinite number of passes would be needed to reach specified tightening
torque.
6. Reset torque wrench to specified torque (Ma) and check all locking screws.
No screw should turn at this point, otherwise repeat Steps 5 and 6.
INSTALLATION WITHOUT A TORQUE WRENCH
7. Tighten locking screws in either a clockwise or counterclockwise sequence,
using approx. 1/4 (i.e., 90°) turns for several passes until the faces of the
outer ring and inner ring are aligned flush. (See Figure 1 - After)
REMOVAL
(Refer to Figure 2)
Prior to initiating the following removal procedure, check to
ensure that no torque or thrust loads are acting on the Shrink
Disc, shaft or any mounted components.
1. Loosen all locking screws in several stages by using approx. 1/2
(i.e., 180°) turns, following either a clockwise or counterclockwise
sequence, until Shrink Disc can be moved on hub. If the shrink disc
does not release, transfer the appropriate number of screws into
the threaded backoff holes in the outer ring (Figure 2). Evenly and
progressively tighten these screws, in either a clockwise or counter
clockwise sequence, until outer ring releases. The shrink disc, hub
and shaft will return to their original clearance fits.
Important: Prior to removal the ends of push off screws are to be
ground flat and chamfered to prevent damage to screw
and outer ring threads during backoff.
WARNING
DO NOT
completely remove all locking screws before outer ring is
disengaged from inner ring. A sudden release of the outer ring involves
high separating forces and could result in permanent injury or death. Be
certain that outer ring is disengaged from inner ring before completely
removing locking screws.
REINSTALLATION OF SHRINK DISCS
In relatively clean operating conditions, Shrink Discs can be re-used
without prior cleaning. Shrink Discs used under severe conditions, how-
ever, require thorough cleaning and re-lubrication with Dow Corning
®
Molykote
®
G-Rapid Plus Paste or equivalent.
LOCKING SCREW SIZES AND SPECIFIED TIGHTENING TORQUE M
a
Screw Size M8 M10 M12 M14 M16 M20 M24 M27 M30
Tightening
Torque
Ma (ft lb)
25
52
89 140 214 420 730 1092 1460
Wrench Size
Across Flats
(mm)
13
17
19
21
24
30
36
41
46
©2012 Fenner Drives B-PR-025 09/01/2012
Figure 2
INSTALLATION AND REMOVAL INSTRUCTIONS
FOR
B-LOC
®
SHRINK DISCS SERIES SD40
SD40
Grease-free
