Arc flash head protective gear and method for operating thereof

Description

CROSS-REFERENCE TO RELATED APPLICATION

This claims the benefit of German Patent Application DE 102024115832.8, filed on Jun. 6, 2024, the content of which is incorporated by reference in its entirety.

BACKGROUND

An electricians' arc flash protective headgear serves to protect against injuries to the face and the neck of the wearer in the event of an arc fault, which can be triggered, for example, by damage to the installation or by operating errors in electrical installations. It is intended to protect against molten metal splashes, the hot plasma cloud and the radiant heat.

Head protection hoods for protection against arc faults have the property that they cover and protect the entire head all around. This can impede air exchange and make it difficult to communicate with colleagues on site. For this reason, head protection hoods are available in which the visor shield can be opened, thereby offering a comfort function for the wearer without them having to take off the entire hood. This enables fresh air to be supplied and makes it easier to communicate. However, at the same time, there is the risk that the visor shield, which acts as face protection in the head protection product, can no longer be lowered and cannot offer protection in hazardous work situations.

In protective headgear, for example head protection hoods, in which integrated visor shields act as face protection (protective function), the visor can be opened, for example for ergonomic reasons, while being worn (comfort function). The visor is only permitted to be opened if the wearer is not in a hazardous situation. For this reason, there are a number of solutions for informing the user that the protective function is to be activated.

U.S. Pat. No. 829,384 S presents a face protector in which the visor shield can obviously be opened as a comfort function. This face protector is typically integrated into a protective hood that offers 360-degree protection and entirely encloses the head area. To avoid breathing in stale air and to facilitate fresh air supply, the visor can be opened. The face protector published in said document has the comfort function (visor can be opened). However, it does not provide for monitoring the visor position and cannot inform the wearer that the visor needs to be closed to restore the protective function.

US 2019/0150546 A1 describes a retrofittable sensor module for use with a head protector with helmet and visor. The sensor module comprises a sensor housing and a fastening mechanism. The sensor housing encloses a head presence sensor that senses when the head protector is being worn. The sensor housing also comprises a position sensor that senses the position of the visor relative to the helmet. The retrofittable sensor module also comprises a fastening mechanism fastened to the housing. The fastening mechanism mates with a first hinge component of a hinge assembly in the head protector in order to removably install the sensor module in the head protector, wherein the hinge assembly allows the visor to move relative to the helmet.

U.S. Pat. No. 11,039,652 B2 describes a sensor module for a head protector. This sensor module is used in a head protection product, the visor shield of which can also be opened as a comfort function. The sensor module monitors the visor position and also whether the head protection product is being worn. All information is captured electronically, processed externally and can lead to a signal being output for the wearer. If the energy supply of the sensor module is too low, the wearer is also able to open the visor.

The sensor module for head protection published in U.S. Pat. No. 11,039,652 B2 offers the possibility of monitoring the visor position and informing the user of the need to close it (monitoring function). However, if the battery supply of the sensor module fails or the battery state of charge is too low, the monitoring function is no longer available. In this case it is still possible for the user to open the visor and to continue to work with their face unprotected, potentially in the event of danger.

Similar solutions are described in the publications U.S. Pat. No. 9,848,666 B1, US 2017/0 367 426 A1, US 2019/0 318 606 A1, US 2020/0 118 413 A1 and US 2020/0 334 970 A1.

Particularly in products that have already implemented a monitoring function, there is the risk that the users will come to rely on this function. The absence of the monitoring function due to an inoperative sensor module owing to low battery charge does not necessarily lead to the user modifying their behaviour.

The existing head protection hoods equipped with visor shields that can be opened have no function that monitors this situation and closes the visor when the visor is not in use and when the energy supply to the latter is becoming weaker.

SUMMARY

The disclosure relates to electricians' protective headgear for protection against arc faults when working on or near electrical installations and operating equipment, as well as to a method for operating same. The arc flash protective headgear is an item of personal protective equipment which, usually in combination with a headpiece, is worn in front of the face. It consists of a transparent protective screen (visor) that is connected to an immobile frame part acing as supporting structure.

An object of the disclosure is to provide arc flash protective headgear, as well as a method for operating same, in which the protective function for a folding visor is ensured under all conditions, including in particular in the event of a power failure. The comfort function must only be available to the user if a monitoring function is working. The object is achieved by the protective headgear as disclosed herein.

Occupational safety and occupational ergonomics are diametrically opposed to each other, meaning that an improvement in occupational ergonomics (comfort function) must be monitored (monitoring function). According to specifications, any failure of the monitoring function must lead to the comfort function being interrupted, because the protective function has priority in occupational safety equipment.

The arc flash protective headgear consists of an immobile head protection part and a movable visor fastened therein. A monitoring module with a position sensor monitors the visor position and a monitoring module with a sensor system and an indicator (head presence sensor) is used to monitor whether the protective headgear is being worn. The movable visor can be locked with respect to the immobile head protection part in at least one position by an electrically actuatable locking mechanism, wherein the locking mechanism is automatically actuated by means of a sensor and electronics module, the energy supply of which is provided via an energy store or an energy generator.

The sensor and electronics module can be designed as two separate modules that are integrated into the arc flash protective headgear.

The sensor and electronics module can be integrated into a shared housing in the arc flash protective headgear.

In one particular design, the electronics module can be integrated into other parts of the protective equipment, outside of the arc flash protective headgear.

The automatic locking and unlocking can be effected by the electrically actuatable locking mechanism with an electric motor, a linear motor, a magnetic switch/solenoid, a pneumatic system or a hydraulic system.

The head presence sensor for ascertaining whether the arc flash protective headgear is being worn can be a temperature sensor, a radar sensor, an infrared sensor, an ultrasonic sensor, a presence sensor, a gas detection sensor, a distance measuring sensor, a proximity sensor, a motion sensor, a camera system with image recognition or a combination of two or more of these sensors.

The energy supply of the sensor and electronics module can be replaceable batteries, rechargeable accumulators, capacitors, solar cells or other electrical or mechanical energy stores and energy generators.

The method for operating arc flash protective headgear is characterised in that, with the aid of the sensor and electronics module, the movable visor is automatically locked with respect to the immobile head protection part by means of the locking mechanism if the head presence sensor indicates by way of a signal that the arc flash protective headgear is not being worn and/or before the energy supply reaches a low or critical state of charge. After a user activates/switches on the sensor and electronics module, the visor can be or is automatically unlocked. The user is informed by the electronics module via actuatable signal outputs that the visor is open.

The state of charge of the energy supply can be determined and evaluated via characteristic parameters of the energy store or energy generator, such as the battery voltage, the internal resistance, the discharge current or by means of pressure sensors, for example in the case of mechanical energy stores.

The user can be notified that the visor is open by way of a visual, audible or vibrotactile signal.

To protect the user from any unforeseen hazards, the arc flash protective headgear autonomously monitors the visor position and gives the wearer a signal to close the visor (monitoring function). Before it is switched off and if the arc flash protective headgear is no longer being worn, or if the state of charge of the energy supply to the monitoring electronic system is low, the visor shield is automatically closed. As soon as it is no longer possible to ensure the monitoring function, the comfort function can no longer be used. However, the protective function of the visor shield is always available under all circumstances.

The arc flash protective headgear contains an electrically actuatable locking mechanism that is integrated into the protective headgear. The locking system comprises a lock for locking the visor shield of a head protector in an outer frame. The lock is automatic and connected to a sensor and electronics module. The sensor and electronics module contains a head presence sensor to detect whether the head protector is being worn. The sensor and electronics module also comprises a position sensor which senses the position of the visor relative to the outer frame. Furthermore, the sensor and electronics module comprises monitoring the status of the energy source.

The method for solving the object is implemented by processing the signals from the position sensor, the head presence sensor and the energy source in an electronics module, followed by outputting signals to the user and to the actuator of the visor locking mechanism.

The visor locking mechanism is characterised in that the movable visor can be locked in the closed position with respect to the outer, fixed part of the head protector. The automatic locking and unlocking is carried out automatically by an electronics module, which is integrated into the head protector together with the energy supply and sensors.

The method for implementing the object is defined such that the visor is automatically locked when not in use before the switching off and/or before a low or critical state of charge of the energy store or the energy supply is reached.

The visor is unlocked and the comfort function is enabled if the user activates the sensor and electronics module when the monitoring function is switched on. As long as the monitoring function is active, the user is informed by signals that the visor is open and needs to be closed.

The advantages of the invention include monitoring the comfort function. The comfort function is deactivated if no monitoring function is possible. This increases protection by reducing operating errors, for example when working with open visors. The protective function is maintained even when there is no energy supply. The protective function is independent of the energy supply. This is a technical solution that prioritises the protective function over the comfort function. This means that a monitoring function monitors the comfort function and informs the user that the visor needs to be closed. Should the monitoring function no longer be provided, for example due to low battery charge, the visor should be locked so that it can no longer be opened. This means that the protective function is always provided, even in the absence of any monitoring.

In addition to protection against arc faults, the headgear can also be used in other personal protective equipment in which only a closed visor shield guarantees complete protection against hazards. The means that the automatic locking mechanism can be used in any protective headgear in which a visor shield is an integral constituent part of a protective function and these visor shields can be opened. One example is breathing hoods, which can only protect a person from dangerous gases in the closed state. In welding safety helmets as well, the eyes can only be protected from the intense light of the welding arc when the visor is lowered.

The invention is explained in more detail hereinbelow with an exemplary embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an arc flash protective headgear with closed visor.

FIG. 2 shows the arc flash protective headgear with open visor.

FIG. 3 is a detailed view with closed locking mechanism for the visor.

FIG. 4 is a detailed view with sensor and electronics module and open locking mechanism for the visor.

DETAILED DESCRIPTION

A first exemplary embodiment is illustrated in FIGS. 1 to 4. FIG. 1 shows arc flash protective headgear with a closed visor 8, which is integrated into an immobile head protection part 9. Typically, both parts are fastened to a hard hat 10.

The visor 8 can be opened, as shown in FIG. 2, without the hood having to be removed. The sensor and electronics module 1 is located in the lower, front chin area of the arc flash protective headgear. FIGS. 3 and 4 show a detailed view with a sensor and electronics module 1 and an open or a closed locking mechanism 3 for the visor 8. The sensor and electronics module 1 in this version contains all of the following components: position sensor 2, visor locking mechanism 3, energy supply 4, signal processing 5, head presence sensor 6 and a signal output 7.

The mode of operation is as follows:

After the user switches on/activates the sensor and electronics module 1, the visor 8 is unlocked and the monitoring function is activated. As soon as the visor 8 is opened, this is detected by the position sensor 2. It sounds an audible signal, which prompts the user to close the visor 8. The signal can sound different, depending on whether the head presence sensor detects whether the arc flash protective headgear is being worn or not. The signal goes quiet as soon as the position sensor 2 detects that the visor 8 is closed.

If the electronics ascertain that the energy supply 4 in the form of a battery has a low state of charge and the visor 8 is open, a further signal sounds, which prompts the user to close the visor 8. The visor 8 is automatically locked by the locking mechanism 3 of the visor 8 if the visor 8 is closed and it is not worn for a certain amount of time or a low state of charge of the energy source is detected. This is done by closing the locking tappet 11 located on the drive motor 13 in the corresponding locking lug 12.

Further options include the following:

The position sensor 2 can be realised by different components, for example by a photoelectric sensor, a microswitch, a proximity sensor, a radar sensor, an infrared sensor, an ultrasonic sensor or similar sensors, which can determine the position of the visor shield relative to protective headgear.

The head presence sensor 6 can also be realised using different components, for example a temperature sensor, a radar sensor, an infrared sensor, an ultrasonic sensor, a presence sensor, a gas detection sensor, a distance measuring sensor, a proximity sensor, a motion sensor, a camera system with image recognition or a combination of two or more of these sensors.

The visor locking mechanism 3 can be an electric motor, a linear motor or a magnetic switch or a solenoid. It can have a pneumatic or a hydraulic design.

The energy supply 4 can be realised by replaceable batteries, rechargeable accumulators, capacitors, solar cells or other electrical or mechanical energy stores and energy generators.

The signal output 7 to the user can be visual, audible or vibrotactile via structure-borne sound.

The state of charge of the energy supply 4 can be evaluated using various characteristic parameters of the energy store or energy generator, for example via the battery voltage, an evaluation of the internal resistance, the discharge current or by means of pressure sensors.

The electronics realised by the signal processing 5 and the signal output 7, the battery supply 4, the locking mechanism 3 and the sensors 2, 6 can be placed independently of one another at various positions on the protective headgear or even on other components outside the protective headgear. However, they can also be concentrated in one module. Communication between the electronic components can take place via cables or wirelessly.

REFERENCE DESIGNATIONS

• • 1 sensor and electronics module
  • 2 position sensor
  • 3 locking mechanism
  • 4 energy supply
  • 5 signal processing
  • 6 head presence sensor
  • 7 signal output
  • 8 visor
  • 9 immobile head protection part
  • 10 hard hat
  • 11 locking tappet
  • 12 locking lug
  • 13 drive motor