Pole Vault in Rio 2016: A Contest of Skill or a Contest of Patents?

With the Rio 2016 Summer Olympics getting started on August 5th, there is no time like the present to explore the evolution of patents relating to the vaulting pole. Originally, pole vaulting was a practical way to cross obstacles, such as rivers or enemy walls. Inevitably, this led to competitions among Ancient Greeks, Cretans and Celts. The pole vault became a male Olympic sport in 1896, while the female pole vault made its Olympic debut in 2000. As you might expect, the pole used by vaulters has changed significantly since the sport’s inception.

In a hundred years, the vaulting pole has changed from a piece of hardwood to an intricately-built piece of fiberglass and carbon fiber, assembled through patented methods. Unsurprisingly, the pole vault record is the most frequently broken world mark in men’s track and field history. As of 2014, the International Association of Athletics Federations (IAAF) has reportedly ratified 71 world records, set by 33 different vaulters. The current record holder is Renaud Lavillenie of France, who cleared a height of 6.16 metres in Donetsk, Ukraine in 2014. To put this into perspective, the world record in 1904 was 4.02 metres. The best pole captures all of the energy transferred to it by the vaulter and efficiently transfers it back to the vaulter as they are launched into the air. Minimal increases in the world record in the last decade have hinted that the combination of materials technology and athletic performance may be reaching its peak. The heights achieved by modern pole vaulters undoubtedly rely on the pole. However, with all vaulters equipped with similar fiberglass poles, the sport becomes a truer contest of technique.

The Technology

Originally, vaulting poles were made out of hardwood, typically solid ash or hickory. Starting around the beginning of the 20th century, bamboo poles began to dominate the sport. These poles were significantly lighter their hardwood counterparts, allowing for a faster run up. More importantly, they could bend, whereas hardwood poles could not.

The next innovation in poles came along with the introduction of aluminum as a key material. The Carpenter patent (U.S. 1398/2,113,826) discloses a hollow vaulting pole made from an aluminum alloy. The invention provides for a significant reduction in weight over vaulting poles formed of wood which typically require a large diameter to prevent splintering. The invention’s one-piece design is swaged into successively smaller cylindrical sections throughout its length to create a pole that gradually reduces in diameter up to where the vaulter grips the pole. Furthermore, the bottom end of the pole is closed with a convex-shaped endcap that acts as a pivot when the pole contacts the ground. The rounded endcap replaced a metal spike at was normally attached to the bottom of the wooden vaulting poles.

The Lindler patent (US 1970/3,491,999) represents an improvement in the manufacture of vaulting poles made using the next key material: fiberglass. It discloses a glass-fiber reinforced vaulting pole that possesses 10% greater hoop strength than previous glass-fiber vaulting poles. To manufacture the improved vaulting pole, knitted glass-fiber tape pre-impregnated with a thermosetting resin is wrapped around a mandrel. Next, pre-impregnated longitudinal glass-fiber filaments are laid about the tape substantially parallel to the axis of the mandrel. Four layers of cellophane tape, two layers clockwise and two counter-clockwise, are then helically wound about the longitudinal glass-fiber filaments. The assembly is hung in an oven heated to a range of temperatures for specific durations to cure the epoxy resins. After the cooling, the mandrel and cellophane are removed. Next, a helical winding of glass-fibers, pre-impregnated with a thermosetting resin, is applied to the surface of the pole. After curing and hardening the winding to the pole, the pole is cut to its desired length and is fitted with a pivot endcap in one end and a plug in the other.

The Jenks patent (U.S. 1976/3,969,557) presents a fiberglass vaulting pole manufactured in a way to improve hoop strength. The pole is built on a mandrel by first helically winding epoxy impregnated fiber glass tape into a continuous succession of butt-jointed turns with the tape’s fibers extending lengthwise of the tape. Next, a rectangular shaped piece of epoxy resin impregnated fiberglass broadcloth is wrapped multiple times over the tape. A fiberglass tape, identical the first tape, is then helically wound over the cloth in the direction opposite to the first tape. Since the taped turns are crossed with one another, the butt joints of each tape are reinforced by the tape of the other layer. Next, another cloth wrapping is added but with an isosceles trapezoidal shape. Having the trapezoidal wrapping as the outer layer is advantageous because changes to the shape of the trapezoid and the number of times it is wrapped around the mandrel can be used to alter the pole’s design. Finally, the mandrel comprising the four wrappings goes into an elongated curing chamber which applies heat to cure the resin and external pressure to compact the fiberglass and epoxy into a unitary rigid structure. The two tape layers give the pole great hoop strength since the fibers on the tape extend primarily around the pole, is in contrast to woven tape where 50% of the fibers extend lengthwise and do not contribute to hoop strength. With the broadcloth being located between the tape layers, it acts as a column load barring member since its lengthwise fibers are firmly fixed in position to resist splitting.

The Johnston patent (U.S. 1984/4,468,024) improves upon its predecessors by describing a vaulting pole endcap designed to provide additional forward penetration of the pole into the plant box. This design allows the vaulter to hold the pole higher and hang for a greater period of time below the rotating pole.

The Watry et al. patent (2008/ U.S. 7,438,962) presents a vaulting pole manufactured with five filament layers in which at least one is a carbon weave layer. The preferred location of the carbon weave is in the second layer of the body wrap due to its strength in all directions. The weight of the vaulting pole can be further reduced by replacing additional fiberglass layers with carbon fiber layers. Most world class vaulters have continued to use 100% fiberglass poles as the reduction in weight provided by carbon fiber does not overcomes the slight decreases in durability.

The Bentley patent (2012/U.S. 8,147,383) introduced a vaulting pole with an angular deviation away from the pole’s lengthwise dimension for increasing the vaulting pole plant angle and providing an ergonomic hand grip. The greater the pole angle a vaulter can achieve when planting the pole in the plant box, the greater the vaulter’s ability to move the pole toward the landing pit. This invention has not yet gained widespread use by vaulters.

Canada in Rio

Canada is a medal threat in both the men’s and women’s pole vault in Rio. Shawnacy Barber of Toronto enters as the reigning men’s world champion after his win at the 2015 World Championships in Beijing. Earlier this year, Barber joined the 6-metre club, becoming its 19th member and, at age 21, the youngest ever to clear the height. On April 9, 2016, Alysha Newman of Delaware, Ontario set the new Canadian women’s pole vault record by clearing a height of 4.6 metres. Newman, at age 22, enters Rio as the 4th ranked women’s vaulter in the world. The men’s pole vaulting final starts at 8:35 pm on Monday, August 15, while the women’s pole vaulting final starts at 8:30 pm on Friday, August 19. Be sure to tune in to cheer on our Canadian vaulters all the while contemplating the remarkable evolution in pole vaulting patents.

Justin Philpott is an IPilogue Editor and a JD candidate at Osgoode Hall Law School.

 

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