Web forces, Asymmetrical wrap (see figure 12), Symmetrical wrap (see figure 11) – Nexen MB25B 911996 User Manual
Page 8
FORM NO. L-20127-L-0513
8
NOTE
When installing M B Tension Sensors with
asymmetrical wrap, angle A must be on the same
side as the Pivot Point or angle A’ must be on the
side away from the Pivot Point.
ASYMMETRICAL WRAP (See Figure 12)
When angle A is less than angle B, or angle A’ is less
than B’, the web angle is asymmetrical. The force acting
perpendicular to the top plate can be computed from the
following formulae:
Wrap Angles (Check appropriate boxes.)
Angle a = 90
o
Angle A or A’ =
o
Angle B or B’ =
o
Angle A- B; or A’ - B’ = D
o
o
-
o
= + D
o
NOTE
If D
o
is > 25
o
, consult factory. If D
o
is < 25
o
,
proceed
with force calculation.
For Normal Wrap
Where:
F = Resultant Force.
T
= Web Tension.
F = (T cos A) + (T cos B)
_______+_______=_______
For Reverse Wrap
Where:
F’ = Resultant Force.
T’ = Web Tension.
F’ = (T’ cos A’) + (T’ cos B’)
_______+_______=_______
FIGURE 12
T
F
A
B
T
T '
B '
F '
A '
T '
Nor mal
Wr ap
R ev er s e
Wr ap
Pivot
Point
a
�
a
D
D
SYMMETRICAL WRAP (See Figure 11)
When angle X = angle Y, or X’= Y’, the web angle is
symmetrical. The resultant for F or F’ will act into or away
from the top plate or MB Tension Sensor at 90
o
. In this
condition, F or F’ can be determined by the formula:
For Normal Wrap
Where:
F = Resultant Force.
T = Web Tension.
F = 2T cos X
For Reverse Wrap
Where:
F’ = Resultant Force.
T’ = Web Tension.
F’ = 2T’ cos X’
WEB FORCES
(continued...)
FIGURE 11