Jungle gym



The jungle gym or climbing frame is a piece of playground equipment made of many pieces of material, such as metal pipe or rope, on which children can climb, hang, or sit.

History
The first jungle gym was invented in 1920 and patented by lawyer Sebastian Hinton in Chicago. It was sold under the trademarked name Junglegym. The term "monkey bars" appears at least as far back as the 1930s, though Hinton's initial patent of 1920 appeals to the "monkey instinct" in claiming the benefits of climbing as exercise and play for children, and his improvement patents later that year refer to monkeys shaking the bars of a cage, children swinging on a "monkey runway", and the game of "monkey tag". Hinton's father, a mathematician, had built a similar structure from bamboo when Hinton was a child; his father's goal was to enable children to achieve an intuitive understanding of 3-dimensional space through a game in which numbers for the x, y, and z axes were called out and each child tried to be the first to grasp the indicated junction. Thus the abstraction of Cartesian coordinates could be grasped as a name of a tangible point in space.

Hinton's second prototype jungle gym is still standing at Crow Island School.

Varieties
Large, metal, geometric-shaped jungle gyms were once common on playgrounds, but they sometimes led to injuries when children hit their heads on the bars or swung on them improperly, causing bruises, sprains and fractures. Newer jungle gyms are often made of alternative materials, including PVC, other plastics, rope varieties, wood/pipe and other materials. Non-metallic jungle gyms have the advantage of being user-friendly even on a very hot or very cold day, because they do not get too hot or too cold to the touch. Jungle gyms and monkey bars made of PVC and plastic flex when struck, absorbing the impact better than more-rigid metal models. PVC and plastic will not rust.

Jungle gym shapes may include wooden platforms with ladders and railings around the outer edges. A variety of shapes are seen in school playgrounds, parks, and backyards, including geodesics, rocket-shaped structures, and other configurations.

One common type of jungle gym is a row of overhead bars, high enough for a child to hang from, but not so high as to cause serious injury in a fall. A child can swing hand-over-hand from one end to the other, or hang upside down from the bars.

Safety
To reduce the risk of injury from falls, jungle gym areas often have a thick layer of woodchips or other impact-absorbing material covering the ground; the US National Safety Council recommends that playgrounds have at least 12 inches (30 cm) of such material.