Some Hydraulic History
Hydraulic power is a natural phenomenon and has shaped the world around us. The human version of hydraulic power was used for crop irrigation many thousands of years ago as human civilisations developed. We are only going to touch on mobile hydraulic power and a few brief points about how it came to be on construction equipment as the overall subject is vast.
Much is written about Mr. Armstrong and his inventions but the use of water to power dockside cranes around 1845 is the breakthrough I would like to reference. Mr. Armstrong's hydraulic accumulator is also key as it ensured water pressure was available to power the cranes.
Despite being born in 1810 he was an advocate of renewable energy from water and solar. If you visit Mr. Armstrong's residence of Cragside Northumbria you can see an exhibit of the hydraulic cylinder used to power a lift in 1868 (as well as the first domestic electric lighting powered by a water turbine generator).
Tractors bucking or overturning backwards and injuring or killing the operators when the plough hit a large object in the ground was a problem with early tractor plough designs, with the plough also often being towed rather than being solidly attached to the tractor.
Harry Ferguson worked on the task of finding a better and safer tractor rear linkage arrangement to prevent this bucking motion. After a series of rear hitch improvement patents Mr. Ferguson incorporated mobile hydraulics into the patent issued in 1926 developed on what is commonly called the "black tractor". The linkage design geometry meant when the plough hit upon a large object in the ground the combined traction and linkage loads would act to push the front axle down into the ground making the linkage itself fundamentally safe
The hydraulics built into the tractor in the later 1926 hitch design were used to position the plough but also to relieve the loads as the upper linkage actuated a hydraulic valve when under excess loads repositioning the plough in the ground to relieve that load (thus creating a hydraulic mechanism feedback system).
Mr. Ferguson partnered with David Brown initially creating the Ferguson-Brown model A and then more famously with Henry Ford after the famous "handshake agreement" between the two gentlemen. Much is written about the tractor 3 point hitch, but I am referencing the use of mobile hydraulics on an agricultural tractor in 1926 as key to it becoming the choice for most construction equipment.
We now have tractors with integrated hydraulic systems. The next logical step was to use the hydraulic systems to control other implements through control valves, hydraulic cylinders and mechanisms.
World War 2 had a massive effect on the mobile hydraulics industry. Mobile hydraulics existed on machinery before WW2 but the systems and components tended to be lower pressure and not particularly high precision (and hence not so reliable, or leak free).
The use of mobile hydraulics in the aircraft landing gear and control surface movement in WW2 meant that mobile hydraulics needed to become higher pressure, more reliable and less leaky very very quickly.
As you would expect the US, UK, Italy, Japan, and Germany rapidly invested in mobile hydraulics as part of the preparation for WW2 and during the war itself.
Post WW2 many more advanced hydraulic systems and components were surplus to requirements and became available to inventive individuals and companies to use to the develop the next generation of agricultural and construction equipment. These next generation machines adopted the more reliable & controllable mobile hydraulics in place of the cable or chain implement control winch systems used previously.
