Hydraulic rescue kit

Rescue scissors cutting the C-pillar of a Volvo S60

Spreaders in different sizes

Rescue spreader (left) and scissors (right)

The hydraulic rescue set is a compilation of hydraulic devices with accessories, which are operated by units ( motor pump or motor pump unit ); but there are, B. as a makeshift, also manually operated rescue kits. Hydraulic rescue equipment is used for the rescue and recovery of people in accidents on the road or rail and in other accidents. Mainly fire brigades and the technical relief organization are equipped with these devices. Military units that are used for these activities (in Germany for example the fire brigade ) also use hydraulic rescue kits.

Rescue shears have been in use since the 1970s. In 1974 the first rescue scissors in Austria were handed over to the voluntary fire brigade in Reutte . At that time it was powered by a two-stroke engine.

Structure of the rescue kit

Rear view of a fire engine with a rescue kit at the bottom right

A rescue kit consists either of a separate (rescue) spreader and rescue scissors , possibly supplemented by one or more rescue cylinders and possibly an additional device, or a combination device that combines the function of spreader and scissors. But this advantage is bought with a smaller opening width of the spreader and a slightly lower cutting force. The hydraulic rescue kit is driven by a hydraulic pump with currently approx. 700 bar , but with some models also significantly more. Since the pump and tools are separated from each other, they are connected by hydraulic hoses. The hoses are often on reels for ease of use . In the case of smaller work tools, these are often already connected to the hoses and can therefore be used more quickly.

In addition to the unit-operated devices, there are also cordless devices that combine a battery, hydraulic pump and combination spreader in one housing.

Battery-operated hydraulic rescue set with rescue cylinder, scissors, spreader and combination device (from left).

In the event of mass accidents , the devices offer better mobility and range than hose-connected devices. The devices built from 2011 onwards are designed by most European manufacturers in accordance with the requirements of DIN / EN 13204 and NFPA 1936 for ambient temperatures from −20 to +55 ° C. However, there are no regulations in these two standards for battery-operated rescue equipment, which means that they cannot be certified according to them.

Working principle

Animation hydraulic cylinder

The hydraulic rescue kit unfolds its effect through a double-acting hydraulic cylinder . A valve allows the oil to flow through the hydraulic pump in two directions so that the devices can exert both pressure and tension. Whether the scissors or the spreader opens or closes, i.e. in which direction the oil is pumped, is regulated by a control at the rear end of the handle, which is called the actuator. If the control part is released, the hydraulic rescue device remains in the current position. This means that unintentional opening or closing is technically impossible.

Hydraulic rescue devices can be used very precisely, spark-free and almost silently, which is advantageous for patient-friendly rescue because unnecessary, psychologically stressful noise is avoided. Likewise, injured persons are protected by the vibration-free work that the devices enable.

Rescue spreader

The rescue spreader , also simply called a spreader , is used to spread apart, for example, jammed or deformed car doors or to push away wreckage. However, it can also be used to compress or lift different materials. Thanks to the multifunctionally designed spreader jaws - they are made of drop-forged and hardened, sharp-edged steel - it is also possible to get into the smallest of gaps or to peel sheet metal. A special chain set can also be used to pull the spreader, for example to pull the steering column of a motor vehicle away to free injured persons . However, due to the current design of the steering columns with cardan joints, this method is no longer used. Instead, rescue cylinders (see below) are used nowadays, with which the entire engine block is folded away forwards.

Exemplary performance data of a rescue spreader in the medium performance class
Opening width of the spreader arms: up to approx. 800 mm
Spreading force: approx. 450 kN
traction: approx. 99 kN
Squeezing force: approx. 120 kN
Hydraulic pressure: 350-700 bar

Rescue scissors

The hydraulic rescue shears (also called hydraulic cutting devices more rarely ) are used to cut through materials in the event of a traffic accident, for example to cut off the roof of a car.

The ever-advancing improvement in passive safety in the passenger car sector creates additional problems for the fire services due to the materials and special profiles installed in the vehicles. For example, the B-pillars of modern cars are so stable that rescue shears with a maximum cutting force of over 1.25 MN are required. Rescue shears of this strength are not easy to use because of their heavy weight.

The work is also made more difficult by installing additional airbags , since the pyrotechnic gas generators of these devices can burst when severed. They represent a great danger for bystanders and working firefighters (see also AIRBAG rule ).

The increasingly harder body parts (especially the vehicle pillars) pose new problems for the cutting devices. If the force of the scissors is no longer sufficient to cut through the columns, material must either be removed in advance or the column is torn out with the help of rescue rams. The gas pressure dampers (e.g. on the tailgate or the bonnet) and the door hinges, on the other hand, are no longer a problem for modern cutting devices.

The hydraulic rescue shears were originally developed by Wilhelm Fischbach from Wuppertal to cut through the underground telephone cables of the post office, which were often as thick as an arm , and which until the beginning of the 1970s were painstakingly separated with hacksaws. It was only later that the idea of using these scissors to cut free people trapped in an accident occurred. Previously, this was done using cutting torches or cutting discs with the risk of acute fire or explosion.

Rescue ram

Rescue cylinder set

Usually one or more hydraulic rescue cylinders , also called hydraulic cylinders , are part of the rescue kit . The rescue ram is used, for example, to push away the front part of the accident vehicle. For this purpose, the sill is cut at the level of the A-pillar (paying attention to pyrotechnic belt tensioners or load cables in hybrid vehicles) (often not necessary for deformed vehicles) and the rescue cylinder is positioned diagonally between the A-pillar and B-pillar . With newer vehicles, care should be taken to ensure that the dashboard cross member is hit on the A-pillar so that the pillar does not simply tear off. Depending on the version, these devices can enlarge openings from approx. 320 mm to up to 1640 mm; forces of up to 270 kN act in this area. Telescopic rescue cylinders (see picture) achieve maximum opening width with compact dimensions and a small initial length. Depending on the design, rescue rams are suitable for pushing and pulling. They are mainly used when the opening width of the rescue spreader is no longer sufficient. In connection with a sill attachment, the rescue ram can be attached optimally and safely (no slipping off). This protects the B-pillar sufficiently and prevents the cylinder from breaking through.

Cutting device for low-tension cutting

A small cutting device can also be part of the rescue kit. Due to its small dimensions, it can cut pedals in the footwell or seat hinges. This cutting device, also known as a pedal cutter , works with little tension because, in contrast to the normal cutting device, only one blade can be moved.

equipment

General accessories

The hydraulic rescue kit is supplemented by various accessories depending on the needs of the individual rescue and aid organizations. This includes e.g. B. various attachment aids (draw hooks and chains to pull a steering column), timber or substructure material, equipment for glass management ( spring punch , glass cutter , foils or adhesive tape for masking windows), belt knives , aids for patient protection , airbag protection and much more.

Spreader chain

The spreader chain allows the rescue spreader to be used to pull objects together. It consists of two hook chains and a suspension hook that is mounted on the tip of the spreader. By closing the spreader, tensile force can be applied to objects.

The spreader chain is used in patient-friendly rescue operations by pulling the steering column of a vehicle away from a trapped person, making it easier for them to be freed. However, since there is an additional risk of injury for the victim, the fire brigades in many places have switched to pushing the engine compartment forward using rescue rams. This offers the additional advantage that the spreader remains freely available.

Areas of application of the rescue kit

Notice from the ÖAMTC that a rescue card is on board.

When the fire brigade is deployed in the vehicle sector, the hydraulic rescue kit is increasingly being used for cutting free in vehicles that have had an accident. Since, however, cable harnesses or airbags are often installed in the vehicle parts that have to be worked on with the rescue shears to open a vehicle , particular caution is required here. To make these dangers easier to recognize, some vehicles have an ambulance card on board.