Where were springs invented?

The story of the spring is not one of a single "Eureka!" moment but rather a long, gradual evolution from simple natural materials to the complex, precision-engineered components used today. For millennia, humanity understood the basic principle of energy storage through elasticity, long before a formal name or metal construction was ever conceived. The most fundamental expression of this concept, the non-coiled spring, has been present throughout human history, evident in the earliest survival tools like the bow and arrow. Dating back as far as 64,000 years ago, this simple weapon utilized the flexing of a bow—often made of flexible yew wood—to store energy for propelling an arrow. Anytime a flexible element is tightened to create a bounce or stored potential, that action embodies the core function of a spring.

# Ancient Metalwork

As metallurgy advanced, so did spring technology. In the Bronze Age, people began fashioning more sophisticated elastic devices out of metal. A clear example of this early sophistication is the spread of tweezers across many cultures, which rely on the elastic property of shaped metal to function. Furthermore, the ancient Egyptians were far more advanced in their vehicle engineering than many modern observers assume. Chariots depicted around 1333 BC featured complex suspension systems incorporating what look like springs and shock absorbers, offering structural dynamics and ride quality comparable to early 20th-century designs. This suggests that even in antiquity, mechanical concepts were being developed to manage impact and load, although these early forms were primarily variations of leaf or simple bent metal springs.

The concept of using an elastic material as part of a larger mechanism rather than as the primary object itself—as seen in the bow—was established early. For instance, draw bows and crossbows utilized spring-triggering mechanisms in biblical times, preceding the birth of Christ. Later, in medieval times, the principle was adapted for siege weaponry, where torsion springs crafted from materials like bull's hair were incorporated with long wooden arms to launch heavy projectiles.

# Coiled Appearance

The design that most modern people associate with the term—the coil spring—did not appear until much later. Coiled springs first emerged in Europe around the 15th century, finding initial application in door locks. This innovation soon led to the development of the first spring-powered clocks within that same century, which evolved into the first large watches by the 16th century. These early coiled designs were often made of flat metal, rather than the rounded wire common today, and were praised for saving space compared to earlier designs.

The application of springs in weaponry also saw a significant mechanical leap around this time. Around 1493, Leonardo Da Vinci customized a spring mechanism for the matchlock pistol, a design innovation that finally made it possible to fire the weapon with a single hand. This mechanism involved a wheel lock where a powerful spring released tension, forcing the wheel to strike pyrite and create a spark to ignite the powder. Flat springs continued to be essential components in firearms and locking mechanisms throughout the 15th century.

When was the first metal spring invented?

# Physics and Patents

While manufacturing techniques slowly advanced, the underlying science governing springs was being formalized. In 1675, British physicist Robert Hooke articulated his famous principle, ut tensio sic vis—as the tension, so the force—now known as Hooke's Law. This law states that the restorative force a spring exerts is approximately proportional to its extension or compression ($F = -kx$), though this linearity only holds true within the material’s elastic limit. This foundational physics insight, established in the late 17th century, still serves as the basis for analyzing the behavior of most conventional springs.

The first official registration for a coiled spring came over a century later. In 1763, R. Tradwell filed British patent number 792 for the coiled spring design. This was a significant improvement over the existing flat or leaf spring technology, which often required frequent separation and lubrication to prevent annoying squeaking.

The advent of the Industrial Revolution in the 19th century saw springs transition from specialized mechanisms into mass-market components. In the 18th century, French engineers put an arc-shaped plate onto carriage suspensions, marking the first true leaf spring used on a transportation vehicle—a necessary addition given the rough state of roads at the time. Despite this early vehicle application, the steel coil spring, which offered greater efficiency, was officially invented and patented in America in 1857, initially finding its way into chair seats. A poignant footnote in this era is the story of Heinrich Westphal in Germany, who is credited with inventing the innerspring mattress in 1871 but reportedly died in poverty, never profiting from his widely adopted design.

It is fascinating to consider the parallel development of comfort technology. While the 18th-century French leaf spring offered an advance over rigid axles, it was still a relatively rudimentary solution for vehicle movement. We can see a historical pattern: the initial application of spring concepts served vital functions like warfare or essential mechanics (like clocks), and only later, with the advent of better materials and mass production, did the focus shift significantly toward passenger comfort, whether in carriage seats or mattresses.

# Manufacturing Acceleration

The early 1900s brought about "quantum leaps" in spring manufacturing driven by the burgeoning automotive and farm equipment industries, which demanded springs faster and in greater volume than manual methods could supply. This period saw a flurry of activity where, in less than five years, patents were secured for essential new equipment, including adjustable spring winders, hand winding tools, and early automatic spring coilers. This marks a critical divergence in spring history: the acceleration of production capability. While Hooke's law defined what a spring should do based on its geometry and material in the 17th century, the Industrial Revolution—especially post-1930s—focused on how quickly that precise geometry could be replicated thousands of times over.

By the 1950s, looping machines were introduced, increasing the speed and accuracy of extension spring production. This manufacturing maturation enabled entirely new applications, moving springs from simple mechanical buffers to highly specialized components in complex systems.

When was the first spring clock invented?

# Specialized Designs

Not all springs are helical coils. One specialized design that gained prominence due to superior manufacturing control is the wave spring. Although the concept of a wavy washer existed before, the true wave spring was invented by Smalley in the late 1960s. The difference lies in the manufacturing process: traditional wavy washers are stamped from flat sheets, resulting in a grain structure that follows the stamped circle, limiting load tolerance to about $\pm 30\%$. Wave springs, conversely, are created by edgewinding flat wire on edge, which results in a circular-grain metallurgy that increases material strength and stability. This method allowed wave springs to achieve a much tighter load tolerance of $\pm 10\%$. The first significant application for this superior component was in Bayonette Connectors, where consistent coupling torque was essential, thereby disrupting the entire connector market.

Another important variant is the torsion spring, which operates by twisting rather than being compressed or extended axially. These springs are key in mechanisms requiring rotational force, such as helping doors open and close quickly, or powering drawers and latches.

In general, springs are classified by how the load is applied (tension, compression, torsion) or by shape (flat, serpentine, machined, etc.). Common metal choices for modern springs include various grades of spring steel, but also materials like phosphor bronze and titanium when corrosion resistance is required.

# Modern Significance

Today, springs are integral to nearly every facet of modern engineering, with estimates suggesting over 90% of mechanically produced items require some form of spring mechanism. Their ability to harness, transfer, and output energy without fuel remains a unique and irreplaceable feature in engineering.

The role of springs extends to the most advanced technological achievements:

• Aerospace: Springs were crucial in the Apollo 11 mission, specifically in the landing gear deployment system. NASA reportedly tested this deployment up to 250 times, working to mitigate issues like insulation interference and low spring energy discovered during early thermal-vacuum tests.
• Architecture: Even the world's tallest structure, the Burj Khalifa (828m tall), uses large springs as part of its tuned mass dampening system to ensure stability against high winds and seismic activity.
• Transportation: High-speed Shinkansen bullet trains in Japan, introduced in 1964, rely on springs to achieve a critical balance between speed (up to 320 km/h), safety, and passenger comfort through vibration dampening and impact absorption.
• Personal Devices: Modern phones utilize springs in miniature motors for vibration alerts and in physical buttons like volume controls. Even essential medical devices like pacemakers incorporate springs to secure batteries, establish reliable electrical connections, and facilitate sensing mechanisms.

From a simple bow used for hunting 64,000 years ago to the high-precision components ensuring the stability of a skyscraper or the safe landing of a spacecraft, the invention of the spring is less about a single date and more about the continuous refinement of elastic principles across materials and manufacturing techniques. The initial leap was recognizing elasticity as a tool, but the subsequent revolutions—from the coil patent to the automatic coiler—are what truly changed the world.