Hydraulic rescue tools, also known as jaws of life, are used by emergency rescue personnel to assist in the

extrication Vehicle extrication is the process of removing a patient from a vehicle which has been involved in a motor vehicle collision. Patients who have not already exited a crashed vehicle may be medically (cannot exit a vehicle due to their injuries) or ...

of victims involved in vehicle accidents or railway accidents and cutting large-sized debris of mild metal structures into smaller pieces for extraction of injured/dead victims out from building rubble in earthquake-raged areas, as well as other rescues in small spaces. These tools include cutters, spreaders, and rams. Such devices were first used in 1963 as a tool to free race car drivers from their vehicles after crashes.

History

The Hurst Rescue Tool was invented by George Hurst, circa 1961, after he viewed a stock car race accident in which it took workers over an hour to remove an injured driver from his car. Previously rescuers often used

circular saw A circular saw or a buzz saw, is a power-saw using a toothed or Abrasive saw, abrasive disk (mathematics), disc or blade to cut different materials using a rotary motion spinning around an Arbor (tool), arbor. A hole saw and ring saw also use ...

s for

vehicle extrication Vehicle extrication is the process of removing a patient from a vehicle which has been involved in a motor vehicle collision. Patients who have not already exited a crashed vehicle may be medically (cannot exit a vehicle due to their injuries) or ...

, but these suffered from several drawbacks. Saws can create sparks, which could start a fire, create loud sounds, stress the victim(s), and often cut slowly. Alternatively, rescuers could try to pry open the vehicle doors with a crowbar or

Halligan bar A Halligan bar (also known as a Halligan tool or Hooligan tool) is a forcible entry tool used by firefighters. History The Halligan bar was designed by New York City Fire Department (FDNY) First Deputy Chief Hugh Halligan in 1948 and was named ...

, but this could compromise the stability of the vehicle, or injure the victims further. In comparison, hydraulic spreader-cutters are quieter, faster, stronger, and more versatile: they can cut, open, and even lift a vehicle.

Hurst Performance Hurst Performance, Inc. was an American manufacturer and marketer of automobile performance parts, most notably for muscle cars. History Hurst Performance was originally named Hurst-Campbell. The company was established in 1958 as an auto repa ...

began to export parts to a European company, Zumro ResQtec, to avoid import duty. Zumro ResQtec was interested in developing these tools for use in

auto racing Auto racing (also known as car racing, motor racing, or automobile racing) is a motorsport involving the racing of automobiles for competition. In North America, the term is commonly used to describe all forms of automobile sport including non ...

, with ResQtec targeting the European market and Hurst targeting the American market. The hydraulic spreader was originally developed in 1972 by Tim Smith and Mike Brick, who later developed a cutter and a hydraulic ram. When an occupant is trapped the tool is used to pry or cut the car to remove the occupant. It takes about two minutes to take the roof off a car. Mike Brick coined the phrase "Jaws of Life" after he observed people saying that their new device "snatched people from the jaws of death", then used as a registered brand name for Hurst products. The name "jaws of life" is, however, used colloquially to describe other hydraulic rescue tools. Brick later developed a single rescue tool that combines the functions (push, pull, cut and spread) of previous rescue tools, and patented it; the design is currently implemented as the Phoenix Rescue tool.

Tool types

Cutters

The cutter is a pair of hydraulically powered shears that is designed to cut through metal. Cutters are most commonly used to cut through a vehicle's structure in an extraction operation. They are sometimes specified as to their capacity to cut a solid circular steel bar. Cutter blades are replaceable, and blade development progresses as vehicle technology progresses in order to be able to cope with the new car protection technology.

Spreader

A spreader is a hydraulic tool that is designed with two arms that come together in a narrow tip, and that uses hydraulic pressure to separate or spread the arms. The tip of the tool can be inserted into a narrow gap between two vehicle panels (such as between two doors, or between a door and a fender), then operated to create or widen an opening. Spreaders may also be used to "pop" vehicle doors from their hinges.

Combination spreader

While a cutter or spreader tool is designed for a particular application, a combination tool (also known as a combi-tool or spreader-cutter) combines cutting and spreading functions into a single tool. In operation, the tips of the spreader-cutter's blades are wedged into a seam or gap—for example, around a vehicle door—and the device engaged. The hydraulic pump, attached to the tool or as a separate unit, powers a

piston A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder (engine), cylinder a ...

that pushes the blades apart with great force and spreads the seam. Once the seam has been spread, the now-open blades can be repositioned around the metal. The device is engaged in reverse and the blades close, cutting through metal. Repeating this process allows a rescuer to quickly open a gap wide enough to pull free a trapped victim. The blades can spread or cut with a force of several

ton Ton is any of several units of measure of mass, volume or force. It has a long history and has acquired several meanings and uses. As a unit of mass, ''ton'' can mean: * the '' long ton'', which is * the ''tonne'', also called the ''metric ...

s or

kilonewton The newton (symbol: N) is the unit of force in the International System of Units (SI). Expressed in terms of SI base units, it is 1 kg⋅m/s2, the force that accelerates a mass of one kilogram at one metre per second squared. The unit i ...

s with the tips of the blades spreading up to a meter. This operation can also be performed by dedicated spreading and cutting tools, which are designed especially for their own operations and may be required for some rescues. Spreader-cutters sometimes have lower capabilities when compared to the dedicated tool (e.g. a smaller spreading range) but may be useful where space is at a premium on fire and rescue vehicles, or when the budget does not allow for a separate cutter and spreader tool. Many manufacturers utilize the body of their dedicated cutting tool for the combination tool. Specially engineered combination blades that are designed to spread and cut are used on the cutter body. If the end user decides later to add a separate cutter and spreader, the blades of the combination tool can be changed to make it a cutter only.

Extension rams

An extension ram consists of a piston or telescoping cylinder that extends under hydraulic pressure to exert force on vehicle structures. Rams are used less often than spreader-cutters in auto rescues, but serve an important purpose of creating space in compacted vehicles. Rams can extend and apply directed force much farther than the arms of a spreader, making them ideal for reaching deep into crushed vehicle compartments. For example, a ram may be used to push away the dashboard to free a trapped occupant’s legs. There are many types and sizes of rams, including single-piston, dual-piston and telescopic rams. Sizes commonly vary from to (extended). Rams use more hydraulic fluid during operation than spreader-cutters, so it is essential that the pump being used has enough capacity to allow the ram to reach full extension.

Power

The tools operate on the basis of the hydraulic fluid pressure of up to , which must be provided from a power source. At present, there are three different means of generating pressure. The most commonly used source is a separate power unit, small petrol (gasoline)

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ge ...

connected to a hydraulic pump. The hydraulic fluid is pressurised in the pump and conveyed in a hose under pressure to the tool. Alternative power sources are a small electrical pump in the tool powered by a heavy-duty rechargeable battery or hand- or foot-operated pumps, also connected to the tool directly. These are useful for lighter-duty use and do not require the storage space taken up by the separate power unit and associated lengths of hose. Some manufacturers have begun offering all-electric products driving rotation motors or a screw piston. These are still relatively new on the market and thus may still be somewhat immature but potentially offer many benefits over hydraulic such as but not limited to lower cost of ownership, quicker, more direct and responsive operation, decreased weight, improved portability and handling, and greater reliability.

References

External links

* Bonsor, Kevin (August 24, 2001)
"How the Jaws of Life Work"

HowStuffWorks HowStuffWorks is an American commercial infotainment website founded by professor and author Marshall Brain, to provide its target audience an insight into the way many things work. The site uses various media to explain complex concepts, term ...

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