Dead man's facility

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A dead man's handle , even motion alarm , Deadman , Totmannwarner , deadman switch , dead-man pedal , dead-man or pass device called to check whether a person is present and able to act and, if otherwise triggers a signal or a switching action from.

Basics

Dead man's circuits are used for work safety at individual workplaces or on dangerous machines and are often required by law, or at least by insurance law. They react to immobility, horizontal body position (dead man's device) or sleep, or they trigger when released and lock or require an additional switching action to switch on again (dead man's switch, for example on hand-held, dangerous machines).

history

The term was already in use in the 1910s, as evidenced by its mention in a patent from 1922. Safety devices for electric vehicles from the 1930s also refer indirectly to such devices.

A gun stand manual (“Turret Manual”) from 1942 of the US Air Force describes a dead man's button that prevents an electrically powered defense stand from turning further when the operating handles are released, already as a “dead man's switch”. The German engineer Siegfried Schulte also owns the patent for a dead man's switch .

species

Dead man's facilities

Mobile dead man's device in use by the fire department
Pressure gauge with an integrated Totmannwarner ( "body guard" of the company Dräger )

These devices, also known as dead man alarms, are a type of motion detector. If a person does not move for a while or (in some cases) performs certain movements, a programmed action is carried out, which can usually be interrupted by pressing a button on the dead man's alarm or by moving it (acknowledging the pre-alarm). The action to be performed differs depending on the type of workplace.

Mobile dead man's devices are used, for example, by wearers of breathing apparatus in the fire service, in Germany also called emergency signaling devices according to fire service regulation 7 . The warning device is attached to the breathing air bottle or the breathing apparatus wearer himself and is activated when the breathing apparatus begins. The dead man's device reacts to movements of the fire brigade. If it remains motionless for a certain time (usually 20 to 30 seconds), a short pre-alarm is issued. If the wearer does not move after the warning, the optical and acoustic (approx. 100 dB ) main alarm is triggered. This allows rescuers to locate the unconscious more easily. Some deadman alarms also have a temperature alarm: if the temperature of the ambient air exceeds a previously set value, the main alarm also sounds.

For individual workplaces with a potential hazard, there are devices that are attached to the belt and react to inclination. If, for example, due to an accident, they become horizontal, they first emit a signal tone. If you stay horizontal, you can use a radio signal and a dial-up receiver to send a telephone call to an emergency room or another adjustable telephone number.

Dead man's switch

On dangerous hand-held devices such as B. chainsaws , dead man switches or dead man handles are often attached. They stop the device as soon as you let go of the handle or switch. Switching on requires an additional switching operation to unlock the dead man's switch. This prevents the device from being switched on accidentally by simply picking it up or dropping it.

Rail vehicles, racing boats and planes

Today the safety driving circuit (Sifa) has replaced the dead man's device on German railroad vehicles ( locomotives , control cars , but also on trams ). In Switzerland one speaks of the security control (SiSte). The driver does not press a button or pedal all the time, but has to briefly release the control element after 30 seconds at the latest. In Switzerland, there are also route-dependent or combined systems. With this he signals that he is still vigilant in the driver's cab. If this action does not take place, the system first issues a visual and then an acoustic warning. If these warnings are ignored, the system assumes that the engine driver is no longer able to act and automatically applies the emergency brake to bring the train or the shunting unit to a standstill.

In some trams, for example in Duisburg , a version is used in which a pedal has to be held against a pressure point while driving. The warning and the braking process are triggered when the pedal is released or fully depressed.

With jet skis , snowmobiles and racing boats, a modified form of the dead man's switch principle can be found in most cases. Before starting, the boat or jet ski driver must put a plastic cable around his wrist, which is attached to a button on the handlebar of the jet ski. If the driver falls off the jet ski while driving, he automatically pulls out the button on the handlebars and the engine switches off. This is to prevent an uncontrolled further journey and too great a distance of the jet ski from the driver and to give the opportunity to get on again. In extreme cases, e.g. B. If the distance from the bank is too great, this represents a protection against drowning. Furthermore, this safety device prevents possible damage to third parties. This type of security is required for operation on German waters including the German coasts. Such a device can also be found on outboard motors and sports equipment such as treadmills.

In certain types of aircraft, a similar circuit helps the pilot to survive in an emergency. The Lockheed F-117 was upgraded after a few incidents with a circuit at night prevents the pilot from disorientation flies directly in the poorly visible soil . According to reports, there was a device in the cockpit of the MiG-29 that brought the machine back into a stable and level flight position at the push of a button or if the pilot was unconscious.

A safety device can also be found when fueling vehicles with pressure - this applies to vehicles powered by compressed gas or large aircraft. A push button must be pressed here to refuel. If it is released, the flow of fuel will stop immediately.

Areas of application

Protection of the person

  • in mines
  • at fire brigades
  • in data centers
  • in semi-automatic parking systems
  • at THW in disaster regions
  • Correctional facilities
  • in the guard duty of the Bundeswehr
  • Individual workplaces with hazards
  • Call assistance
  • psychiatric institutions
  • Night duty

Protection from danger

LPG -Zapfsäule with black dead-man above the filling nozzle
  • in trains, subways and suburban trains ( safety driving circuit )
  • Recognition of driver fatigue (during testing)
  • in tank trucks during the filling and emptying (especially on gas stations) as well as LPG -Zapfsäulen for consumers
  • Control rooms that are manned by only one person (especially at night) (e.g. in smaller water or electricity works)
  • in gardening and landscaping (milling)

Protection on handheld devices

  • Power tools
  • Mining equipment
  • Garden tools
  • Gas stations

Use in the digital and military sectors

  • By means of a deadman automatic trigger actions in the digital environment as soon as someone not periodically logs ( "login"). For example, a whistleblower can ensure that secret documents are made public even after his “death”.
  • On board the B-52 Stratofortress there was a device ( Special Weapons Emergency Separation System ) that ensured that the nuclear weapons carried would detonate in any case, even if the crew were e.g. B. had become incapacitated by enemy action.
  • The dead-hand system is intended to automatically trigger the launch of the Soviet / Russian ICBMs if a nuclear strike is detected by appropriate sensors. It has also been speculated that the UVB-76 shortwave transmitter is related to this system.

Individual evidence

  1. ^ Andy Newman: Train Stopped Safely by 'Dead-Man Feature' . In: The New York Times , April 28, 2010. 
  2. Patent specification: "Safety device for electric vehicles, especially with one-man operation"
  3. http://www.derwesten.de/staedte/luedenscheid/Erfinder-der-sicheren-Schalter-id1612407.html
  4. Handelszeitung : Strange Snowden tweet triggers speculation . August 7, 2016. Retrieved November 17, 2016.
  5. Archived copy ( Memento of the original from January 18, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.sew-lexicon.com
  6. The Limits of Safety by Scott Douglas Sagan; 1995 Princeton University Press; ISBN 0691021015 ; Page 187-188.