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THE WORKINGS OF THE HYDRAULIC JIB


Hydra 150 Jib
The Hydra 150 had four parts with the second and third section both extended hydraulically.
This was achieved with only one hydraulic ram. This pushed the second section of the jib, the third section was pushed out with a chain attached to the second section. This enabled all three section to move in unison.

Hydraulic jibs were not new but the systems were still being perfected. The problem of the hydraulic jib was one of making very long cylinders that could take the pressures existed on then.

Extending jibs had been developed but had been operated by cables and chains which being internal to the jib were often not maintained. the hydraulic jib solved this problem by providing a system that had very few parts that needed regular maintenance.

Demonstration models of hydraulic jibs were used by the training school the factory. This was run to train crane operators and service mechanics.

Models built 1:5 scale Model sizes aprox 35"x6"x11" high (875x150x275mm)

At this time Cole made three types of extending jibs, They all had the basics in common the difference being the number of sections that could be hydraulically moved.
The smallest had a single powered section, the next had two powered sections and the largest on the biggest cranes had three fully powered sections.
Hydra 70 Jib

The smallest Hydra 70 size jib simply had a single hydraulic cylinder pushing on the number two section of the arm. the third extending section of the main boom had to be extended manually.



Hydra 300 Jib
The largest of the tree jibs was the Hydra 300, this had two hydraulic rams one pushing the second section out and a second operating the third section.
This arrangement allowed for a much longer jib operating under hydraulics because rather than having and effective extension of one length of cylinder, that is the distance the arm can push out the hydraulic ram, you effectively have three extension distances. The first ram arm length plus the second cylinder and ram arm.



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