Jackhammer

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Jackhammer" – news · newspapers · books · scholar · JSTOR (December 2008) (Learn how and when to remove this message)

A jackhammer (pneumatic drill or demolition hammer in British English) is a pneumatic or electro-mechanical tool that combines a hammer directly with a chisel. It was invented by William McReavy, who then sold the patent to Charles Brady King.^[1] Hand-held jackhammers are generally powered by compressed air, but some are also powered by electric motors. Larger jackhammers, such as rig-mounted hammers used on construction machinery, are usually hydraulically powered. These tools are typically used to break up rock, pavement, and concrete.

A jackhammer operates by driving an internal hammer up and down. The hammer is first driven down to strike the chisel and then back up to return the hammer to the original position to repeat the cycle. The effectiveness of the jackhammer is dependent on how much force is applied to the tool. It is generally used like a hammer to break the hard surface or rock in construction works and it is not considered under earth-moving equipment, along with its accessories (i.e., pusher leg, lubricator).^[2]

In British English, electromechanical versions are colloquially known as "Kangos". Also the terms drill and breaker (demolition hammer) are non-interchangeable and refer to two differing distinct types of jackhammer (regardless of their power source). A breaker cannot rotate its steel (which for example may be either a chisel or spike) and relies on pure percussion shock to fracture and split material without cutting. Whereas a (pneumatic/hydraulic) drill both impacts and rotates, which enables a steel with a tungsten carbide tipped bit to cut into hard rock such as granite, typically to create holes for blasting. Normally only the pneumatic drill would be used at geological operations such as quarrying or mining and only the breaker at civil operations such as construction and road repair.