Hydraulic rescue tools are used by emergency rescue personnel to assist
vehicle extrication of crash victims, as well as other rescues from small spaces.
These tools include cutters, spreaders, and rams. They are popularly referred to
in the English speaking Commonwealth nations and the US as the Jaws of Life,
a trademark of Hurst Performance, Inc. The Jaws of Life were first used in 1963
as a tool to free race car drivers from their vehicles after crashes.
Hydraulic rescue tools are powered by a hydraulic pump, which can be hand-,
foot-, or engine-powered, or even built into the tool. These tools may be either
single-acting, where hydraulic pressure will only move the cylinder in one
direction, and the return to starting position is accomplished using a
pressure-relief valve and spring setup, or dual-acting, in which hydraulic
pressure is used to both open and close the hydraulic cylinder.
History The Hurst Rescue Tool was invented by
that company's founder, George Hurst, after he viewed a stock car race
accident in which it took workers over an hour to remove an injured driver from
his car. That was about 1961 and the tool reached the prototype stage of
development in 1971. Previously rescuers often used circular saws for vehicle
extrication, but these suffered from several drawbacks. Saws can conduct
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, but this could compromise the
stability of the vehicle, injure the victims further, or inadvertently
trigger the airbags of the vehicle. In comparison, hydraulic
spreader-cutters are quieter, faster, stronger, and more versatile: they can
cut, open, and even lift a vehicle. Jaws of Life is a now trademarked line of
tools originally developed by Hurst Performance. Hurst Performance 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, 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." Later Brick went on to develop a
single rescue tool that could perform all the functions of rescue — push,
pull, cut and spread. His patent for this unique design eventually led to the
Phoenix Rescue tool, which incorporates his design to this day. Other
manufacturers make equivalent tools. Tool types
= Cutter = The cutter is a hydraulic tool which is
designed to cut through metal—a pair of hydraulically powered shears. It is
often called the jaws of life, owing to the shape and configuration of its
blades. Sometimes specified as to its capacity to cut a solid circular steel
bar, these are most commonly used to cut through a vehicle's structure in an
extraction operation. 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 designed with two arms which come together in a
narrow tip, and which 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
— when the tool is operated, the arms are opened, pushing apart the metal in
the panels. Spreaders may also be used to "pop" vehicle doors from their
hinges. = Spreader-cutters =
Whilst a cutter or spreader tool is designed for a particular application, a
combination tool, or combi-tool as popularly referred to by the fire
department, is also available which combines the cutting and spreading
functions of separate tools 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 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 tons or kilonewtons
with the tips of the blades spreading up to a metre.
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 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.
= Rams = Rams are used far less than
spreader-cutters in auto rescues; nonetheless, they serve an important
purpose. There are many types and sizes, including single-piston, dual-piston and
telescopic rams. Sizes commonly vary from 50.80 cm to 178 cm. 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 hydraulic fluid pressure of up to 720
bar, which must be provided from a power source. At present, there are three
different means of generating the pressure. The most commonly used source
is a separate power unit, a small petrol engine 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, and a
hand- or foot-operated pump 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.
See also bolt cutter
References External links
Bonsor, Kevin. "How the Jaws of Life Work". HowStuffWorks