Formsprag Clutch • 800-927-3262
P-222-14-FC • 5/19
3
Angular Clearance
Axial Clearance
END VIEW
B
Shaft Rotation
1.0
(25.4)
1.0
(25.4)
0.5
(12.7)
Important:
Angular and axial clearances must be
maintained at all times. Set collars (or other
retention devices) should be used on the shaft to
maintain axial clearance.
Figure 2
The torque arm reaction force is the force which the
torque arm stops must resist. Formsprag recommends
that the stops be at least 3/4 of the distance (B) away
from the center line of the clutch.
Installing
1. Place inboard set collar on shaft. Set collars
should be used to keep Holdback in position on
shaft. Otherwise, the Holdback might shift on
shaft causing torque arm to bind.
2. Coat Holdback bore, shaft and key with an
anti-seize compound to facilitate installation
and removal. A supply of this compound is
furnished with each new clutch assembly.
3. Place Holdback and key on shaft. Be sure that
shaft is free of nicks and burrs.
Note:
Oil lubricated Holdbacks should be
mounted on horizontal shafts only. For
mounting on vertical shafts, contact
Formsprag.
4. Apply pressure to end face of inner race only.
Pressing against the outer race could preload the
bearings excessively. To simplify mounting, should
a bore-to-shaft fit of .001 inches tight be required
(this is tightest allowable) immerse Holdback in
hot, clean oil (not to exceed 200°F/93°C) for ten
to fifteen minutes before mounting.
5. Secure Holdback in position on shaft. Use flat
washer fastened to shaft end with screw, snap
rings or set collars to keep Holdback in position
on shaft. It is essential to hold unit in position on
the shaft.
6. Position Holdback and torque arm. Coat torque
arm pins and pin holes with anti-seize compound
(furnished). Insert pins and cotter keys as shown
in (Figure 1).
7. Attach torque arm stops to conveyor frame or
supporting structure. The stops are required to
prevent rotation of torque arm when holdback
torque is applied. Allow clearance between
stops and torque arm as shown in Figure
2. The clearance is necessary to permit free
axial and angular movement of the torque arm
resulting from shaft runout and eccentricity.
We recommend set collars on shaft to prevent
Holdback from shifting which would eliminate
this clearance.
Note:
Torque arms may be installed at any angle,
however, vertical torque arms should be
installed at lease 10° from the true vertical
position. The Holdback should be mounted
in an orientation so that the weight of the
torque arm will keep the torque arm in
constant contact with the reacting surface
and structure.
8. Grease auxiliary seals. These labyrinths are built
into each Holdback to minimize the harmful
effects to the oil seals from dusty or abrasive
atmosphere. For instructions on regreasing these
seals, follow instructions in (Figure 3).
Grease In
Purge
Grease
Out
Figure 3
9. Install oil sight gauge attachment. Follow
instructions in (Figure 4).
Install breather in highest position after Holdback
installation is complete. Follow instructions in
(Figure 4).
