thick; at the bottom
end it is secured to the girders of the truck, and at the top is
shrunk on to a large gudgeon 12 in. in diameter, which enters a
casting fixed in the back end of the jib; on the top of the gudgeon
are two steel disks on which an adjustable cap rests; by means of this
and the ties to the tail and the lower end of the strut a proportion
of the weight can be brought on to the post so as to relieve the
roller path to any desired extent, and enable the crane to be revolved
easily.
The truck is 24 ft. long and 16 ft. 41/2 in. wide; it is constructed of
longitudinal and transverse box girders 2 ft. 8 in. deep, and rests on
two axles 6 in. in diameter; round these axles swivel the cast-iron
bogie frames which carry the ground wheels. This arrangement was
adopted because the crane has to travel up a gradient of 1 in 30, and
the bogies enable it to take the incline better; they also distribute
the weight more evenly on the wheels. The gauge of the rails is 15 ft,
the wheels are 2 ft. 6 in. in diameter, and have heavy steel tires.
The weight on each of the front wheels when running with the ballast,
but no load, is about 16 tons. A powerful brake is applied to the
wheels when descending the incline.
All the clutch levers, break treadle, and handles are brought
together, so that one man has the crane under his entire control.
Pages:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25