Falls from heights remain one of the most common causes of fatalities and severe injuries around the world. The risks associated with work at heights are well known, and it is common to use safety harnesses which can be manually attached to a safety rope by means of at least one carabiner. In many cases, people fail to secure themselves properly while working at heights because of poor training, tiredness, overconfidence or other reasons.

It is therefore the purpose of this invention to provide an improved safety carabiner as well as an improved safety system comprising at least two such carabiners to improve the safety of people working at heights.

These and other objects of the invention are achieved by means of a carabiner according to the independent claim. The carabiner comprises a frame with a swing gate turnable between an open state, in which the carabiner can be attached to and removed from a safety rope, and a closed state, in which the carabiner cannot be attached to or removed from the rope. According to the invention, an electrical locking system is provided to lock the swing gate in the closed state to the frame, and to release the swing gate in the open state from the frame. By this, an accidental manual opening of the carabiner can be avoided.

It might be provided that the locking system comprises a slidable locking pin which, in the closed state, forms a positive connection between the frame and the gate and, in the open state, releases the gate from the frame. It might further be provided that the locking pin is attached to a magnetic or ferroelectric plunger, which is movably supported in a solenoid which houses an electric coil to exert a magnetic field on the plunger, wherein a push springer pushes the locking pin through the frame into the gate when the electric current in the coil is lower than a predefined threshold value, and the plunger is pulled out of the gate by the magnetic field of the coil when the electric current in the coil exceeds a predefined threshold value.

It might further be provided that the carabiner comprises a compartment with an electrical power source such as a battery, a controller unit such as a programmable microcontroller, and an electrical current output driver stage connected to the coil in order to activate the electrical locking system.

It might further be provided that the carabiner comprises a button to activate the electrical locking system, wherein the button is arranged at the gate and preferably connected to a mechanical switch which is connected to the controller unit. This has the particular advantage that a user who wants to open the carabiner first has to push the button to release the locking system.

It might further be provided that the carabiner comprises a communication unit such as a wireless communication unit, in particular a near-field-communication (NFC) unit, and preferably an antenna, so that the controller unit can send and receive data to and from an external device, such as another safety carabiner, a remote control, or a stationary unit located in a safe are, for example less than 2 m above the ground.

It might further be provided that the carabiner comprises an electrical sensor to detect if the carabiner is attached to a rope, wherein the electrical sensor is connected to the controller unit. In particular, it might be provided that the carabiner comprises a swing arm which, upon attaching the carabiner to a rope, is moved from a first position, in which it crosses an opening of the carabiner, to a second position, in which it aligns to the frame, wherein the electrical sensor to detect if the carabiner is attached to a rope comprises a permanent magnet on the swing arm and a corresponding magnetic switch on the frame, so that the magnetic switch is activated when the swing arm is moved to the second position. It might be provided that the controller unit comprises an ampere meter to measure the current through the coil and is adapted to, upon activating the electrical locking system, calculate the impedance of the coil and compare it with a predefined impedance value in order to detect if the locking system is in a malfunction state.

It might further be provided that the frame and the gate comprise ferromagnetic material, wherein a coil is wound around the frame and connected to the controlling unit, so that the controlling unit can sense if the carabiner is attached to a current-carrying wire, such as a current-carrying wire embedded in a safety rope, by measuring the current magnitude or the current pattern induced in the coil with an ampere meter and comparing the measured current magnitude or current pattern with at least one predefined magnitude or pattern.

It might further be provided that a multitude of current patterns, corresponding to different types of safety ropes, are predefined in an electronic storage of the control unit, so that the control unit can detect the kind of safety rope to which the carabiner is attached based on the measured current pattern in the coil.

It might further be provided that the controlling unit is adapted to communicate with an external device to receive a first command to activate the locking system and not permit the user to detach the carabiner, and to receive a second command to unlock the locking system and permit the user to detach the carabiner.

The invention further relates to a system comprising two safety carabiners according to the invention, each comprising a control unit adapted to sense if the respective carabiner is attached to a rope. In a favorable embodiment of the invention, the control units are adapted to, if the first carabiner is not attached to a rope and the second carabiner is attached to a rope, send instructions from the first carabiner to the second carabiner to lock and do not permit to be manually detached from the rope. In analogy, the control units might be adapted to, if the second carabiner is not attached to a rope and the first carabiner is attached to a rope, send instructions from the second carabiner to the first carabiner to lock and do not permit to be manually detached from the rope. Both carabiners might be equipped with sensors to detect if a safety rope or a safety rail is attached inside the carabiner. The two carabiners exchange information and if one carabiner is attached to a safety rope and the other is not, then the one that is attached to a rope remains locked and does not allow the user to detach it, until the other carabiner is eventually attached to a safety rope. This way the person using the device is secured at all times as at least one carabiner remains attached to a safety rope at any given moment.

It might be further provided that the two carabiners can only be both detached when the user reaches a where there is no danger of falling from a height. Whether the user is in a safe area can be determined by a command sent via the communication unit from a stationary unit, located in the safe area. In a preferred embodiment the wireless communication unit is based on near field communication (NFC) technology. With NFC the safe area recognition will be very precise as the command will be received only from a short distance and the command will definitely not be received outside the safe area. The pair of carabiners will also communicate from a short distance and there is no chance of external interference. In other embodiments, the pair of carabiners might be connected with wires, which improves the reliability of the communication.

In a further embodiment of the invention, a system comprising a safety carabiner according to the invention, a current source and a set of particular safety ropes is provided, wherein the carabiner is able to detect if it is attached to a particular rope. For this, the rope comprises an embedded electrically conductive wire which is connected to the current source, wherein the current source is adapted to supply a predefined electrical current pattern through the wire, so that the control unit can identify the rope by detecting the current pattern induced in the coil and comparing it to a set of predefined current patterns. Non-constant and non-sinusoidal electrical currents with distinct patterns might be passed through the embedded wire. A current measuring device can further indicate if the rope is not compromised as the loop will not function if the rope is broken. The frame and the gate of the carabiner can be made of material with some magnetic properties, such as ferromagnetic material, so that it acts like magnetic circuit when its gate is closed. Variations in current in the embedded wire will then cause magnetic field variations inside the frame and the gate of the carabiner. An Electromotive Force is generated in the coil around the frame of the carabiner and therefore electrical current is induced. The electrical current induced will be proportional to the first derivative of the electrical current in the wire embedded in the rope. This dependence can be used so that the programmable microcontroller on the carabiner would recognize if a specific rope is attached as every rope in a selection of ropes at the site would have a different current pattern in its corresponding embedded wire.

In the enhanced embodiment the carabiner acts like an electrical meter clamp but it also has current patterns in its memory and can recognize if the carabiner is attached to a specific rope by matching the current pattern in the wire embedded in the attached rope with a pattern stored in the memory of the programmable microcontroller. In case the rope is not recognized to be the correct one the software may not allow the other carabiner from the pair to be detached and /or some kind of warning to the user to be displayed.

Further features of the invention will become apparent from the attached claims, description of particular embodiments, and figures. The invention is now described in more detail using the attached figures, wherein

Fig. 1 shows a carabiner according to the invention in the closed state;

Fig. 2 shows the carabiner according to the invention in the opened state;

Fig. 3 shows the carabiner according to the invention in the closed state with an attached safety rope;

Fig. 4 shows a block diagram of a safety system according to the invention;

Fig. 5 shows a block diagram of a further safety system according to the invention;

Fig. 6 shows a carabiner according to the invention in the closed state with an attached safety rope comprising a wire;

Fig. 7 shows a flow diagram for the operation of a safety system according to the invention;

Fig. 8 shows a carabiner according to the invention in a malfunction state. Fig. 1 shows an exemplary embodiment of a carabiner according to the invention. The carabiner comprises a frame 6 and a gate 8 and is further equipped with a solenoid 1 with a coil 2, push spring 3, plunger 4 and locking pin 7. In the exemplary embodiment the spring 3 pushes the plunger 4 and locking pin 7 to lock the gate 8, when there is zero electrical current in coil 2. When electrical current is passed through coil 2 plunger 4 is pulled by the magnetic field of the coil 2 and the locking pin 7 releases the gate 8.

Presence of an attached rope is detected by a swing arm 5, permanent magnet 11 , and magnetic switch 10. The magnetic switch 10 is activated when the permanent magnet 11 is brought close the magnetic switch 10, thus indicating if a rope is attached inside the carabiner.

An electronic compartment 12 contains a battery 16, programmable microcontroller 14, wireless communication module 15, and an electric switch 13. An “open gate” request is registered from the button 9 which when pressed activates the mechanical switch 13.

The programmable microcontroller 14 receives data indicating the status of the magnetic switch 10 and the mechanical switch 13. The programmable microcontroller 14 can also send and receive data via the wireless communication device 15.

Fig. 2 shows the carabiner of Fig. 1 in an unlocked position. The user has pressed the button 9 located at the gate 8. This action activates the mechanical switch 13, indicating to the programmable microcontroller 14 that the user requests to open the gate 8. According to algorithm shown in Fig. 7, the programmable microcontroller 14 may then unlock the gate 8 by activating high current circuit to the coil 2, which pulls the locking pin 7, so that the gate 8 is free to open and consequently a rope can be attached to or detached from the carabiner. In this embodiment, the spring 3 pushes the locking pin 7 to lock the gate 8 if there is no electric current in the coil 2. The exemplary algorithm in Fig. 7 allows locking of the gate 8 only when the mechanical switch 13 and therefore the button 9 are not pressed. Additional sensors and procedures to check if the gate 8 is closed, before locking it with the locking pin 7 may be provided as well. Fig. 3 shows the carabiner according to the embodiment of Fig. 1 and Fig. 2 with an attached safety rope 18. The safety rope 18 pushes the swing arm 5. As a result, the permanent magnet 11 on the swing arm 5 is brought close to the magnetic switch 10, which closes and thus indicates to the microcontroller 14 that a rope 18 is attached inside the carabiner. In further embodiments, the attachment of the safety rope 18 to the carabiner might be detected by an ultrasonic sensor, optical sensor or other known methods.

Fig. 4 shows an exemplary electrical block diagram of an embodiment of a safety system according to the invention. The programmable microcontroller 14 is electrically connected to and can read the status of the mechanical switch 13 and the magnetic switch 10. The status of the mechanical switch 13 indicates if a request to open the gate 8 has been made by the user. The status of magnetic switch 10 indicates if a rope is attached inside the carabiner. The programmable microcontroller 14 can activate a high current electrical connection to the coil 2. The magnetic field created by the coil 2 attracts the plunger 4 which pulls the locking pin 7 (not shown) to open the gate 8. The electrical current to the coil 2 is measured by an ampere meter 17. The programmable microcontroller 14 is connected to a wireless communication device 15, which is equipped with an antenna 20.

Fig. 5 shows an exemplary electrical block diagram of a further embodiment of the invention. The programmable microcontroller 14 is electrically connected to the mechanical switch 13 and can read its status. The status of mechanical switch 13 indicates if a user request to open the gate 8 is active. The programmable microcontroller 14 is electrically connected to a coil 19, which is winded around the frame 6 of the carabiner. In this embodiment, the frame 6 and the gate 8 are made of material with some magnetic properties, such as a ferromagnetic material.

This embodiment enables the microcontroller to sense, if a specific kind of safety rope 18 is attached to the carabiner. Such a specific kind of safety rope comprises an electrically conductive wire 22, which is embedded inside the safety rope 18. When the safety rope 18 is captured inside the carabiner and electrical current passes through the wire 22, the frame 6 of the carabiner will act as a magnetic circuit and therefore a magnetic field will be induced in the frame 6. As stated in Faraday’s law of electromagnetic induction, if the electrical current that passes through the wire 22 varies, an electromotive force (EMF) will act on the coil 19 and electrical current will be induced in the coil 19, which can be detected by the amp meter 21 . Current variations in the coil 19 can be detected and analyzed by the programmable microcontroller 14 and compared with predefined variation patterns in its memory. Thus, the microcontroller 14 can detect the presence of a specific wire 22, embedded in the rope 18, attached inside the carabiner.

In case the rope 18 is not recognized to be the correct one, the software running on the programmable microcontroller 14 may not allow another carabiner from the multitude (or pair) of carabiners to be detached and /or some kind of warning to the user to be displayed. Similarly to the embodiment of Fig. 4, the programmable microcontroller 14 might activate a high current electrical connection to the coil 2. The magnetic field created by the coil 2 attracts the plunger 4 which pulls the locking pin 7 (not shown). The electrical current to coil 2 can be measured by the amp meter 17. It can indicate if the coil 2 functions properly. By measuring current fluctuations, it can be determined if the plunger 4 had moved or not. The programmable microcontroller 14 is further connected to the wireless communication device 15, which is equipped with an antenna 20.

Fig. 6 shows a carabiner according to the invention in the closed state with an attached safety rope 18 comprising a wire 22. A coil 19 is winded around the frame 6 of the carabiner. A wire 22 is embedded in the rope 18, captured inside the carabiner. A programmable controller 14 is electrically connected to the coil 19, winded around the frame of the carabiner 6. In this embodiment, the frame 6 and the gate 8 are made of material with some magnetic properties, such as a ferromagnetic material.

When a varying electrical current passes through the wire 22, embedded inside the safety rope 18 which is captured inside the carabiner, the carabiner will act as a magnetic circuit and therefore the magnetic field inside the frame 6 will vary. As stated in Faraday’s law of electromagnetic induction, EMF will act on the coil 19 and electrical current will be induced in the coil 19, which can be detected by an amp meter 21 (not shown). Current variations in the coil 19 are analyzed by the programmable microcontroller 14 and compared with predefined patterns stored in its memory (not shown). This way it is possible to recognize the presence of a specific wire 22, embedded in a specific safety rope 18 captured inside the carabiner.

Fig. 7 is a flowchart of an exemplary algorithm for the operation of a safety system which comprises at least two carabiners according to invention. In such a set of two carabiners, the electronic safety system can sense when any of the two carabiners is attached to a rope. If one of the two carabiners is not attached to a rope, the other one is electrically locked and cannot be detached from the rope. This way it is not possible for both carabiners to be detached from the safety rope at any moment. A person using such a set of two carabiners is always secured to a safety rope at any moment by at least one carabiner.

The algorithm shown is for the first carabiner of the pair of carabiners. In a first step, the controller 14 detects if the button 13 on the first carabiner is pressed. If this is not the case, the first carabiner remains in the locked state.

If the controller 14 detects that the button 13 of the first carabiner is pressed, this means that the user requests to open the first carabiner. The controller 14 performs a series of checks. First it checks, if the first carabiner is in a safe area, such as close to the ground. This can be done via NFC (near-field communication) or other means of communication. If the first carabiner is found to be in a safe area, the first carabiner is unlocked. Secondly, it checks if the first carabiner is empty, i.e. no safety rope is captured in the first carabiner, by querying the magnetic switch 10. If the first carabiner is found to be open, the first carabiner is unlocked. Thirdly, it checks if a safety rope is captured in the second carabiner. This can be done via NFC (near-field communication) or other means of communication.

If it is found that a safety rope is captured in the second carabiner, the first carabiner is unlocked. If none of these checks succeeds, the first carabiner remains in the closed state, even though the user requested to open the first carabiner. If the first carabiner has been unlocked, the algorithm will wait until the button 13 on the first carabiner is no longer pressed. If the button 13 is no longer pressed, the first carabiner will return in the locked stated.

The algorithm for the second carabiner of the pair of carabiners is the same, only the carabiners are alternated. The cycle could end after a certain time period of inactivity is passed or the device is switched off manually.

Fig. 8 shows a carabiner according to the invention in a malfunction state. For some reason, the locking pin 7 is not aligned with the gate 8 leading to jamming of the locking pin 7 and the plunger 4. As the plunger 4 is made of ferromagnetic material and as it remains inside the coil 2, the inductance of the coil 2 will increase and therefore the impedance of coil 2 will increase. The programmable microcontroller 14 can then activate a high current electrical connection to the coil 2 for a very short period of time and measure the current increase in the amp meter 17 (as shown in Figs. 4 and 5). The current increase will be higher when the locking pin 7 is properly locking the gate 8, as the plunger 4 is outside of the coil 2. Similarly, the current increase will be lower when the locking pin 7 is not properly locking the gate 8, as the plunger 4 is inside the coil 2. In this way, the solenoid 1 can acts as a sensor to detect the position of the locking pin 7 and a possible malfunction can be detected by the controller 14.