Specifications

5
2.2 Mechanical Classification (Grade) and Life
Safety and life for electric chain hoists are guaranteed only when the said equipment is
operated in accordance with the prescribed grade.
Black Bear electric chain hoists have been designed for grade 1Am in the FEM
regulations (FEM 9.511).
Details are provided in Table 2-2.
Average daily operating time and total operating time are determined by load distribution.
Load Spectrum
(Load
distribution)
Definitions
Cubic
mean
value
Average daily operating time (h)
1
(light)
Mechanisms or parts
thereof, usually
subject to very small
loads and in
exceptional cases only
to maximum loads.
k ≦
0.50
≦2 2-4 4-8 8-16
2
(medium)
Mechanisms or parts
thereof, usually
subject to small loads
but rather often to
maximum loads.
0.50 < k
≦ 0.63
≦1 1-2 2-4 4-8
3
(heavy)
Mechanisms or parts
thereof, usually
subject to medium
loads but frequently to
maximum loads.
0.63 < k
≦ 0.80
≦0.5 0.5-1 1-2 2-4
4
(very heavy)
Mechanisms or parts
thereof, usually
subject to maximum
or almost maximum
loads.
0.80 < k
≦ 1.00
≦0.25
0.25-0.5 0.5-1 1-2
Mechanical Classifications due to DIN 15020 or
FEM 9.511
1Bm 1Am 2m 3m
% operating time
Load spectrum 1
% operating time
Load spectrum 2
% operating time
Load spectrum 3
% operating time
Load spectrum 4
Table 2-2 Mechanical classifications