One of the most familiar components in the auto industry—the universal joint—was actually invented centuries before the automobile by a British scientist named Robert Hooke.

When Sir Isaac Newton famously wrote in 1675, “If I have seen further it is by standing on the shoulders of giants,” he was speaking of one man in particular: Robert Hooke, 1635-1703. It seems Newton had slighted his colleague and contemporary and wrote him a letter to make amends. While Newton, the inventor of calculus and the laws of motion, is far better known today, in their time Hooke was every bit Newton’s equal.

Not only a leading scientist of his day (though the term didn’t yet exist) but also England’s leading maker of scientific instruments, Hooke constructed the first useful microscopes and air pumps, using them to make remarkable discoveries. One still taught in science classes today is Hooke’s Law, which established the essential properties of a spring and that a gas behaves like a spring. His accomplishments are far too many to name here, so we will focus on just one of his developments of particular interest to us car people: the common yoke-type universal  joint.

Robert Hooke’s patent drawing, 1676

The basic mechanism of what we call a u-joint was conceived a century before by the Italian Gerolamo Cardano (hence the alternate term, Cardan joint). A pivoting, cross-shaped yoke between two shafts allows one to transmit rotation to the other despite its acute angle. But it was Hooke who worked out the math for transmitting rotary motion in two planes, which is identical to that of a shadow’s motion over a sundial.

While the input side of the joint may rotate at a constant speed, the output side actually varies in speed according to the angle between the two shafts. (See a fascinating video demo here.) But if a pair of yoke joints are placed in tandem, the speed variations cancel each other and we have a type of constant-velocity joint—one that is commonly known as a double-Cardan joint (below). 

Hooke proposed his coupling as a means to produce a clockwork-driven “mechanical sundial” that didn’t require sunlight to tell the time, but it proved to have nearly infinite applications on every kind of machine across the industrial world—including the automobile. While there are other types of u-joints, most of the motor vehicles produced over the past 130 years, we’d  wager, include a Hooke’s joint somewhere, in the drivetrain, steering, or elsewhere. We can even find Hooke’s joints in our toolboxes on those handy flexible sockets and extensions. Hooke never saw or drove an automobile,  but we expect he would enjoy the ride.