Engineering:Crowbar (tool)

Short description: Hand tool used for pulling nails with leverage

A crowbar with a curved chisel end to provide a fulcrum for leverage and a swan neck to pull nails

A crowbar, also called a wrecking bar, pry bar or prybar, pinch-bar, or occasionally a prise bar or prisebar, colloquially, in Britain and Australia sometimes called a jemmy and jimmy (also called jemmy bar), gooseneck, or pig foot, is a tool consisting of a metal bar with a single curved end and flattened points, often with a small fissure on one or both ends for removing nails or to force apart two objects. Crowbars are commonly used to open nailed wooden crates or pry apart boards.

The design can be used as any of the three lever classes. The curved end is usually used as a first-class lever, and the flat end as a second-class lever.

Designs made from thick flat steel bar are often referred to as utility bars.

Materials and construction

Normally made of medium-carbon steel, crowbars can alternatively be made from titanium, which has the advantage of being lighter.

Commonly crowbars are forged from long steel products, either hexagonal or sometimes cylindrical stock. Alternative designs may be forged with a rounded I-shaped cross-section shaft. Versions using relatively wide flat steel bar are often referred to as Utility bars.

Etymology and usage

The accepted etymology identifies the first component of the word crowbar with the bird-name "crow", perhaps due to the crowbar's resemblance to the feet or beak of a crow. The first attestation of the word is dated back to circa 1400. They also were called simply crows, or iron crows; William Shakespeare used the term iron crow in many places, including his play Romeo and Juliet, Act 5, Scene 2: "Get me an iron crow and bring it straight unto my cell."

In Daniel Defoe's 1719 novel Robinson Crusoe, the protagonist uses crowbars as pickaxes but refers to these tools as iron crows: "As for the pickaxe, I made use of the iron crows, which were proper enough, though heavy."

In United Kingdom , Ireland, New Zealand, and Australia , due to the influence of American media "crowbar" may occasionally be used loosely for this tool, but it is still mainly used to mean a larger straighter tool, its original English meaning (see digging bar). The term jammy or jimmy most often refers to the tool when used for burglary.

Types

• Alignment pry bar, also referred to as Sleeve bar
• Cat’s claw pry bar, more simply known as Claw bar
• Digging pry bar
• Flat pry bar
• Gooseneck pry bar
• Heavy-duty pry bar
• Molding pry bar
• Rolling head pry bar

See also

• Digging bar
• Halligan bar
• Tire iron