Snorkel AB46JRT - Manual (Page 49)

Chapter 8 – Operation
AB46JRT – 0260071 45
When the main or riser boom is raised from its rest, the
axle locks into position to maximize the stability of the
machine while the platform is elevated.
All Motion Alarm
The optional all motion alarm sounds loud intermittent
beeps anytime the machine functions are being oper-
ated.
Gradeability
Gradeability refers to the maximum slope that the aerial
platform is capable of travel. Gradeability can be de-
scribed as “theoretical” or “actual” with the slope, or grade,
measured in percent of slope or degree of slope.
Theoretical Gradeability
Theoretical machine gradeability refers to the maximum
slope that the machine is capable of travel under perfect,
or theoretical, conditions. It is based on mathematical
calculation, not practical application.
Some of the factors taken into consideration when cal-
culating theoretical gradeability include:
• Drive motor efficiency
• Machine weight
• Machine center of gravity
• Tire traction
• Tire contact
• Condition of slope
The value for theoretical gradeability will most always be
high when compared to the actual gradeability value. The
perception then is that the machine can climb a steeper
slope than is actually practical.
Actual Gradeability
Actual machine gradeability refers to the maximum slope
that the machine is capable of travel under practical condi-
tions. It, too, is based on mathematical calculation, but it
also takes into account the practical application.
At any given moment when driving the machine on a
slope, at least one, if not all, of the factors contributing
to achieving theoretical gradeabilty will not be at optimal
performance. For example, tire contact may not be the
same at each drive wheel or the slope conditions may not
be optimal, which would then allow for loss of traction.
The value for actual gradeability will always be lower
than the theoretical gradeability value. The perception
then is that the machine can not climb a slope as steep
as it should.
Percent vs. Degree of Slope
Gradeability is most often referenced as a percentage.
That value is based on a slope angle of 45° representing
100% grade.
Angle indicators, or inclinometers, often measure the
angle of the slope in degrees not the percent slope.
Because of that, it may be useful to understand the re-
lationship between percent slope and the degree of the
slope angle as shown in Figure 8.4.
Figure 8.4 – Slope Percent/Degree Conversion
Percent of
Grade
Angle of Slope
in Degrees
45°
40°
30°
35°
25°
20°
15°
10°
5°
5%
10%
15%
20%
25%
30%
35%
40%
45%
50%
55%
60%
65%
70%
75%
80%
85%
90%
95%
100%
0