What Is Power Steering - The Auto Johnny

Assistance

By definition, power steering is a system that assists in the turning of a vehicle. When a driver turns the steering wheel, power steering amplifies this motion’s torque and moves the vehicle’s wheels with greater force. Mechanical assistance has helped exceed an individual’s capabilities since the inception of levers, gears and pulleys. But a simple machine still relies on a person’s strength compared to the work required to move an object. This is where powered assistance becomes invaluable, utilizing a separate source of energy to perform the work while a person is only required to provide an instruction.

Power Steering Predates the Automobile

This is up to interpretation. The first automobiles were often built as one offs and not reported, patented or sold to the masses. The Benz Motorwagen utilized an internal combustion engine, a tubular steel frame and sat on three large bicycle spoke wheels. Patented in 1886 by Karl Benz, to most, this is considered the first. In this case, the egg came about 20 years before the chicken. Not for cars, but for boats.

The SS Great Eastern

The largest ship ever built when launched in 1858, at 692 feet (211 meters) is over half the length of the largest modern container ships. The SS Great Eastern laid the first permanent Atlantic cable making sending a telegraph between Europe to North America seem impossibly fast. In 1866 John Macfarlane Gray, a steam and marine engineer from Scotland, designed a system where steam power from the engine could actuate and maintain position of the rudder. This made accurate control of such a large ship much more feasible.

The Telemotor

Around the same time that Gray fitted the SS Great Eastern with his invention, Andrew Brown, another Scotsman and engineer, working on steam engines and hydraulic cranes, created the Steam Tiller. In 1872 he created the Telemotor, a system where hydraulic fluid under pressure could translate the inputs of the captain to the wheelhouse. This made gears, chains and ropes unnecessary for controlling the ship’s heading in the water. The Telemotor became something so critical to the function of large ships that a similar design is used as a safeguard against major control system failure on many vessels today. How does this relate to cars?

The First Patent

They may seem distant from huge ships in design and use, but how distant? Early cars did often move by steam engine, traverse slowly, have cumbersome designs derived from horse carriages; a generous helping of lumber and little to no suspension. Cars of the era, by today’s standards, resembled boats more than we may like to admit. In 1876 George W. Fitts, an American, patented a system where steam power from a vehicles engine could be routed to a lever between a set of pinion gears on the crank of the engine. This would then turn the front wheels to the left or right based on the driver’s input. Not unlike the Telemotor. This is before cars were even readily available or interesting. To many, a car would have been little more than a curious contraption.

Calm Before the Storm

The early 1900’s saw numerous technological advancements including the first flight by the Wright brothers in 1903. Cars were becoming common and changing shape. All sorts of powered vehicles could be seen. From steam engines to combustion engines like the 1903 Colombia 5-ton truck which had an electric motor in the steering system to reduce the effort of the driver in turning. Even electric drive motors like the 1905 Colombia 4 wheel drive “Quadway” electric truck. Robert E. Twiford patented the first all-wheel-drive systems utilizing power assisted steering. In 1902 Frederick W. Lanchester, an engineer in Great Britain, made a hydraulic power steering system. He also patented “Improvements in the steering and control mechanism of power propelled vehicles” in 1903. He stated that a water pump would move fluid through a rotary drum, operating a steering gear. This is similar to modern steering racks. Many of the systems designed or built by inventors of the day fell by the wayside without the financial means to produce them at scale. As the 1920’s brought faster, heavier cars and trucks with larger wheels and tires, there were more drivers taking more frequent trips at greater distances. Interest in reducing the effort it took to control these vehicles also increased. It wasn’t until 1926 that a viable design would become a reality.

The Beginning (so they say)

Francis W. Davis, an American, working with George Jessup, both engineers, designed, built and installed an engine powered hydraulic pump and steering box onto a 1920’s Pierce Arrow roadster. Together they drove and debuted their creation to 26 engineers in 10 days, featuring it at various auto companies. This is when GM began to take interest, signing a contract with Davis to create similar systems for Cadillacs. Although he patented many designs, he ultimately left just as GM prepared a working prototype in 1933. The Great Depression had taken its hold over America by 1929. Pricey luxuries and development trended downward and questioning necessity became an everyday occurrence. GM canceled their contract with Davis in 1934 without implementing his system into production. Around the time Harry Franklin Vickers started pouring his British engineering firm’s resources into designs he and Davis had worked on, Davis drew the attention of the Bendix Corporation. Bendix manufactured parts for other automobile companies. With Bendix pitching Davis’ designs to GM’s Buick he managed to see some fruit from his labor.

War

The 1940’s were filled with large trucks, planes, significant tragedies and triumphs. This decade saw the first hydraulic primary control surfaces (power steering) for airplanes like the Lockheed Constellation in 1943. Military trucks like the Dodge G-502, Dodge 62 and GMC 506 may not have been the largest vehicles in use, but they were small by no measure. Large, heavy trucks responsible for carrying weapons, soldiers and supplies had to travel long distances over challenging terrain while under heavy loads. The perfect storm provided Bendix and Davis, who had been ready and waiting for the compass of necessity to point in their direction, the contracts they needed to bring their efforts to the world stage. Their work had been called to the fight in numerous vehicles including Chevrolet trucks for the British army. By the settling of dust, decades of work by Francis Davis on an idea tried by many for generations prior, covered European battlefields. Power assisted steering had proven its usefulness.

Accepted

After many of Davis’ patents expired GM took it upon themselves to decide power steering to be worth the investment. They debuted ‘Hydraglide’ on the 1951 Chrysler Imperial. “80% less effort …all the time!”, “Eliminates “wheel fight” on rough roads!”, “Saves wear and tear on your heart and your disposition!”, according to actual brochures for Chrysler full-time power steering. The post war spending by Americans only furthered GM’s commitment while the public began to develop a real taste for the “Finger Light” steering being offered. While components from Bendix and Davis did produce for the engineer who had dedicated much of his life to developing a marketable power steering system, Davis didn’t reap all the rewards he probably deserved. GM began implementing optional power steering on more affordable cars in 1953, opening up the market even further and distancing themselves from the real origin with claims like “Chrysler power steering another Chrysler “Engineering First!””. The public responded well. In the 1960’s, power steering became optional in all American cars.

The Standard

Hydraulic power steering held its own for decades despite other systems existing nearly as long. Today there are three basic forms: hydraulic, electro-hydraulic and electric. Each operates on the same principles in that the work to turn the wheels is done based on the inputs of a driver, while not requiring significant force from the steering wheel.