Hydraulic rescue tool
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 United States, Canada, United Kingdom and Australia as Jaws of Life, a trademark of Hale Products Inc.
Hydraulic rescue tools are powered by a hydraulic pump, which can be hand-, foot-, or engine-powered, or even built into the tool itself. 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 suzzette cylinder.
History
Previously rescuers often used circular saws for vehicle extrication, but these suffered from several drawbacks. Saws can generate sparks, which could start a fire, create loud noise, which could stress the victim, and are often slow cutting. Alternatively, rescuers could try to pry open the vehicle doors using a crowbar or halligan bar, but this could compromise the stability of the vehicle, further injure the victims, or unintentionally activate vehicle airbags.
In comparison, hydraulic spreader-cutters are quieter, faster, and more versatile: they can cut, open, and even lift a car. Jaws of Life is a trademarked line of tools originally developed by Hurst Performance in partnership with Zumro resQtec for use in auto racing, with Hurst targeting the American market and resQtec targeting the European market. The jaws of life derives its name from one of the co-inventors, Jack Allen Watson[citation needed]. When submitting drawings he would often sign them with his initials J.A.W. Over time the device came to be known unofficially within Hurst as Jaws[citation needed], and was later introduced as the Jaws of life. The hydraulic spreader was originally developed in 1972 by Tim Smith, 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.
Other manufacturers (including Holmatro and Lukas, amongst others) make equivalent tools.
Tool types
Cutter
The cutter is a hydraulic tool which is designed to cut through metal. It is often called a crab-cutter, 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 extrication operation.
Spreader
A spreader is a hydraulic tool designed with 2 arms which come together in a narrow tip. The tip of the tool can be inserted into a narrow gap between two vehicle panels (such as between 2 doors, or between a door and a fender) - when the tool is operated, the arms are opened, drawing apart the metal in the panels. Spreaders are used to "pop" vehicle doors from their hinges.
Spreader-Cutters
Both spreading and cutting operations can be performed by combination tools, which are designed especially for their own operations and may be required for some rescues. These tools 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.
Rams
Power
The tools operate on the basis of hydraulic oil pressure of up to 720 bar, which must be provided from a power source. At present, there are 3 different means of generating the pressure. The most commonly used source is a separate power unit, which is a small petrol (gasoline) engine connected to a hydraulic pump. The oil 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-operated pump also connected to the tool directly. These are useful for lighter-duty and do not require the storage space taken up by the separate power unit and associated lengths of hose.
References
http://www.phoenixrescue.com/about.htm