This type is designed specifically to fit on
the Fan End of a worm reduction gearbox
as a standard unit, or it can incorporate the
controlled release or the torque limiting
facility.
In all cases the maximum torque capacities
and shaft capacities are identical to those
shown in the respective tables in this
section. Where it is required to be fitted to
an existing gearbox without a keyway in
the worm shaft, the unit can be supplied
with a proprietary locking ring to provide
the necessary drive medium, with an
appropriate reduction in shaft diameter
capacity (details available on request).
.
Selection procedure for
Bibbigard Backstops
Example
A Bibby Plate Controlled Release Backstop
is required to be fitted to the second
motion shaft of the gearbox in the drive
of an underground conveyor operating
on a 1 in 4 gradient. Gearbox transmits
150 kW at 120 r.p.m. Mounting shaft
diameter 90mm.
1. Select appropriate Service Factor (SF)
from page 66, in this case 3.
2. Calculate shaft torque:
3. From the table on page 67, select unit
which has the next higher torque
rating to 35,823 Nm, which in this case
is the 306 PCR (41,750 Nm).
4. Check Maximum Shaft Diameter of Size
306 PCR unit, which shows that up to a
130mm shaft can be accommodated.
5. Check overall dimensions of Size 306
PCR to ensure that the unit can be
mounted correctly in the space
available.
Note:
Maximum torque ratings above have a Safety
Factor of 2.
Friction materials used in Bibbigard®
Backstops incorporating Controlled Release
features do not contain asbestos.