From railings to emergency stops: safety devices on work platforms

ADead man's switchis a safety device that keeps a machine or vehicle running only when actively operated by the operator—usually by continuously pressing or holding the switch. If the operator releases the switch, the system stops automatically.

Dead man's switchesThey are used in trains, machines, industrial trucks, and work platforms, among other things, and are designed to ensure that a device only operates when the operator is able to act and is present. They thus protect against accidents caused by sudden loss of consciousness or control.

ADead man's switchworks according to the principle ofForced operation: The machine will only operate as long as the switch is actively pressed or held. If the switch is released – for example, because the operator is no longer able to act –the system automatically interrupts the power supplyor activates an emergency brake.

Depending on the application, the dead man's switch can be mechanical (e.g., as a step or handle), electrical, or electronic. It is often used in safety-critical areas such as railway vehicles, machine control systems, industrial trucks, or mobile work equipment. The goal isto prevent unintentional or dangerous machine movementsif the operator fails or leaves the control unit.

AMan down alarmtriggers when the operatorshows no expected activity over a defined period of time– such as not pressing a switch, not moving, or not responding to an acoustic or visual signal.

In practice, depending on the system, a warning is initially issued after a short period of inactivity. If the operator does not respond,The dead man's alarm automatically activates an alarm, stops machine functions or calls for external help – for example in the case of lone workers.

Man down alarms are used primarily inIndividual workstations, inPublic transport vehicles, atsecurity servicesor ondangerous construction sitesThey are used to protect against situations in which people suddenly become incapacitated – for example, due to fainting, accidents, or medical emergencies.

ADead man switch is requiredwhen operating a machine or vehicle there is an increased risk that the operator will suddenly become incapacitated – for example due to fainting, an accident or distraction – and thereby pose a danger to themselves or others.

Typical use cases are:

• Trains and locomotives (regulations according to BOStrab and EBO)
• Forklifts and industrial trucks
• Work platforms and lifting equipment
• Machines with dangerous movements
• Lonely workplaces with fall or health risks

In many areas, the use is regulated by law – for example, by theMachinery Directive,DGUV regulationsorIndustrial Safety OrdinanceThe dead man's switch is used toAccident preventionand is mandatory if the continuous presence and responsiveness of the operator is safety-relevant.

AEmergency stop switchinterrupts in case of emergencyimmediately and completely the energy supplya machine or system. It ismanually triggered, usually by pushing or pulling, and ensures thatall dangerous movements or processes stopped immediately– regardless of the current operating status.

Technically speaking, the switch interrupts the circuit via safety wiring, usually by opening a positively driven contact. After activation, the emergency stop remains actively locked and must be deliberately unlocked or reset before the system can be operated again.

Purpose of the emergency stop switchis to be able to intervene quickly and clearly in a dangerous situation – to protect people, machines and the environment. In many machines, it is required by law, for example, according toDIN EN ISO 13850or theMachinery Directive 2006/42/EC.

AEmergency stop switch is requiredif a machine or systeman immediate danger to persons or property may ariseand a quick stop is necessary to prevent damage.

An emergency stop is required in particular:

• for machine-operated systems with moving parts,
• for stationary machines with high kinetic or electrical energy,
• in production and manufacturing facilities,
• wherever operators or third parties may be endangered by unexpected movements or malfunctions.

TheMachinery Directive 2006/42/ECand the standardDIN EN ISO 13850require emergency stop devices for most types of machines,unless equivalent protective measures existThe only exceptions are small, non-hazardous devices or when the emergency stop does not technically contribute to risk minimization.

In short:An emergency stop is mandatory wherever it is needed in an emergencycan save lives or avert damage.

AEmergency stop switchhas the task ofStop dangers quickly and reliablyby using theThe power supply to a machine or system is immediately interruptedThis immediately stops dangerous movements or processes in order toTo protect human lives,to avoid accidentsandTo limit property damage.

It is not for normal operation, but is aSecurity measure for exceptional situations– for example, in the event of technical defects, operating errors, or when people are unexpectedly endangered. The emergency stop is therefore a central element in the safety concept of any risky machine or system.

AEmergency stop switchmay only be omitted if thesystematic risk assessmentclearly shows thatthere is no significant danger to persons or propertyand the emergency stopno additional security gainThis is the case, for example, with very small, hand-held machines that have a low hazard potential, or with fully enclosed and automated systems where humans are not present during operation.no access to the danger areahas.

The basis for this assessment is the specifications of theDIN EN ISO 13850and theMachinery Directive 2006/42/ECBoth standards require the installation of an emergency stop only if itrepresents a sensible measure to reduce riskIn practice, this means that if the machine is already adequately protected by other technical protective measures – such as guards, two-hand operation or safety controls – the emergency stop can be dispensed with.

It is important that the waivertechnically justified and documentedWithout a clear assessment and proof, the emergency stop switch is mandatory. Because in case of doubt, the following applies:Safety features should never be omitted just because they are rarely used.

AEmergency switch, often alsoEmergency stop switchcalled, is used exclusively inEmergencyused when aimmediate dangerfor people, machines or the environment. To use it, it is – depending on the design –pushed, pulled or hitso that the machine or systemimmediately stoppedThe activation takes placemanually and specifically, usually by a striking red button with a yellow background.

Important: The emergency switchdirectly interrupts the energy supply or stops critical movements, without using the regular control system. It is not a normal control element, but aSecurity measure for exceptional circumstances– for example, in the event of a malfunction, a risk of crushing or if a person is in danger.

After activation, the switch usually remainslockedand mustmanually unlocked or resetbefore the system may be restarted. Operation may only resume after the cause of the hazard has been properly remedied.

Note:The emergency switch is not an off switch – it is a safety feature for emergencies.

OneGround controlis a permanently installed or mobile control unit on theFloor of a work platform, with which the device can alsooperate from outside– independent of the control panel in the work basket. It is primarily used toSecurity: If the operator in the basket becomes incapacitated or there is a technical defect, the device can belowered or switched offbecome.

Floor controls also allow the stagecontrolled entry or exitwithout requiring anyone to be on the platform – for example, during transport, positioning, or emergencies. Many modern work platforms feature ground controls with additional functions such as emergency stop, lift restriction, or status indicators.

In short:The ground control is aSafety and operating optionsthat ensure the operation of the work platformfrom the ground makes it possible, especially in an emergency or to assist with assembly.

ATilt sensormeasures theOrientation of an object relative to the Earth's surface, so theSlope in degreesalong one or more axes. In work platforms, it detects whether the deviceis tilted or tilts, and warns or stops operation when critical values are reached.

Technically, the sensor is mostly based onAccelerometers (MEMS), pendulum mechanics or fluid systemsThese systems detect even the smallest changes in position—for example, when a wheel sinks or the ground is uneven. The measured values are transmitted to the control system of the work platform.

If the measured inclination exceeds apredefined limit, aWarning issuedor the stageswitched offto prevent tipping. Many platforms with active tilt detection only allow safe lowering into the transport position.

In short:Inclination sensors ensure that work platformsonly in the safe inclination rangeoperated – a key element in preventing accidents on uneven terrain.

Onebasket scalemeasures theTotal weight in the work basketa stage – the weight of people, tools and materials. The aim is toDetect and prevent overloadbefore it becomes dangerous.

Technically, the basket scale works viaSensors, which are installed either directly in the basket floor, on the lifting arms or in the hydraulics. These sensors measure the load and transmit the data to the control system. If thepermissible maximum weightis exceeded, the system triggersa warning or an automatic blockthe lifting function is disabled – for example, the platform can no longer extend or move.

Modern systems show the weightdigital in the control panelThis way, the operator always knows how heavily the basket is loaded.

In short:A basket scale protects against overload by measuring the current weight and intervening before it becomes critical – formore safety when working at height.

Base platesareflat, stable plateswhich are placed under the supports or wheels of a work platform toto distribute pressure on the groundThey usually consist ofhigh-strength plastic, aluminum or steeland are available in different sizes and thicknesses.

The use is primarily onsoft, uneven or slippery groundimportant – for example, on gravel, earth, or asphalt. Without base plates, the platform can sink, slide, or tip over. The plates ensurelarger contact areaand thus improve theStability.

In short:Base plates make the ground more stable, prevent the stage from sinking and are aimportant contribution to safe installation– especially in outdoor use or on construction sites.