IT201900001475A1 - BATTERY POWERED WIRELESS SAFETY LIGHT CURTAIN FOR APPLICATION ON THE MOVABLE LEAF OF AUTOMATIC SLIDING GATES / DOORS - Google Patents

Description

Patent application for an invention entitled "BATTERY POWERED WIRELESS SAFETY OPTICAL BARRIER FOR APPLICATION ON THE MOVING LEAF OF AUTOMATIC SLIDING GATES / DOORS"

DESCRIPTION

The present patent application refers to a safety device for automatic gates and / or doors of the sliding type.

In particular, the invention which is the subject of the present patent application relates to the realization of a battery-powered optical barrier, which can be installed on the moving part of an automatic gate and / or door, thus acting as a safety device for monitoring the area where the aforementioned operates. moving part, with the aim of preventing any situations of risk of impact and crushing as indicated in the specific technical regulations.

In particular, the invention which is the subject of the present patent application relates to the realization of an optical safety barrier operating in the infrared band, based on low consumption electronic technology which includes an optical emitting unit (hereinafter referred to as "SLAVE"), mounted on the fixed part and a battery-powered receiving optical unit (hereinafter referred to as “MASTER”), mounted on the primary edge of the sliding door. The "wireless" functionality for sending status and synchronism commands is implemented, preferentially but not exclusively, by means of a digital channel of infrared pulses created by an emitter / transmitter on the MASTER unit and correspondingly a sensor / receiver on the SLAVE unit.

It is known that the risks deriving from a moving gate concern the impact with the person or objects and the crushing of the person or objects.

Usually the safety of automatic gates is entrusted to electric / electronic devices which with various construction methods detect the presence of an obstacle on the trajectory of the mobile leaf and consequently command the stop or the inversion of the movement in order to prevent or mitigate the damage from impact or crushing.

Very often this type of control is entrusted exclusively to devices of the photocell type essentially consisting of an emitter of a light beam and a receiver of the light beam coming from the emitter.

Typically, the emitter and receiver are placed on opposite sides with respect to the point where the object is to be detected.

The detection of the object and therefore, consequently, the inhibition of the movement of the gate, take place when the object interrupts the beam of light.

Detection systems with photocells involve the fact that the detection beam generated is limited to the virtual "line" which is located between the emitter and the receiver and therefore positioned at a certain height from the ground.

It follows that in the lower or upper space, the effectiveness of the system as a safety device is not achievable.

Given the limits highlighted, photocell type systems cannot therefore be considered as real safety devices pursuant to the mandatory legislation.

A further disadvantage of photocell type systems is that in the event of a temporary or permanent failure they do not provide for the inhibition of movement with consequent potential impact or crushing action by the moving gate.

At the state of the art, various types of sensors compliant with specific regulations specifically designed to meet the safety requirements in this field of application are known.

One of the solutions known to the state of the art concerns the creation of the so-called "sensitive active edge" which consists of a rubber extrusion with over elastic shock absorption stroke and an aluminum profile that acts as a support for the extrudate.

Inside the electromechanical ribs, the sensor element, housed under the rubber cover, consists of a mobile mechanical part (such as a steel cord or similar) which runs along the coast for its entire length. length, connected at the ends to one or more normally closed microswitches that work in the absence of current on deformation of the edge: at a certain pressure they send an opening signal of the detection circuit which will consequently act on the motor driver. In resistive-type ribs, the sensor element consists of two parallel strips of conductive material that run along the coast along its entire length and are spaced from each other by a small air gap, as if they were the plates of a capacitor. In this case, any deformation of the sensitive edge causes the two electrodes to come into contact, thus causing the closure of the circuit and the consequent stop / inversion of the motor.

Typically, the sensitive active edge is mounted along the entire height of the mobile leaf, on the part that can come into contact with any obstacle that invades the movement area, mitigating the damage caused by a possible accidental impact due to impact / thrust or crushing. , but without preventing it.

The operating principle of an electromechanical or resistive edge such as those shown is based on the detection by pressure of the rubber edge, active along the entire length of the edge, by means of an obstacle that should accidentally come into contact with the edge itself.

The deformation of the edge through the sensitive rubber edge, in turn activates a microswitch or a contact whose signal is sent (via wire or radio) to the motor control board, which will activate a STOP command (and possible inversion motion) of the moving part, thus limiting any damage.

The main disadvantage of said safety device consists in the fact that it is not preventive but rather activates only after the impact has occurred. For this reason, its installation is not exempt from the measurement of the impact force in order to ensure that the latter is within the limits set by the mandatory technical regulations.

A further disadvantage consists in the need to use a wiring to connect the sensor element (edge) mounted on the moving part (sliding door) with the motor control board which is instead on the fixed part.

To partially obviate the previously described drawback, some more advanced active edge systems provide for the use of an RF radio transceiver (external or integrated inside the edge itself) with built-in battery, which allows to avoid the connection normally made with “flex” cable between the engine control unit and the mobile leaf. From this point of view, the RF transceiver guarantees flexibility and a speed of installation that is certainly better, since in this case the wiring is replaced by the (local) battery power supply and by the wireless radio connection as regards the transmission. the state of the coast (pressure detected / not detected). However, it is known that all radiofrequency based systems are vulnerable to external interference / disturbances (e.g. high frequency electromagnetic fields due to the presence of other wireless networks nearby), for this reason, their installation is not indicated in contexts particularly noisy from the RF point of view.

In the state of the art, there are also known solutions of the type active capacitive edge with battery with RF transceiver: this type of solution aims to add a sort of "preventive" functionality to the classic electromechanical or resistive ribs.

The operating principle is based on the sending of a high frequency electrical signal along the internal conductive part of the coast: in this way, by exploiting the well-known phenomenon of the electric field, the signal radiates locally and interacts capacitively with any other conductive bodies. (metals, humans or animals) detecting their presence even before direct contact.

It therefore prevents any dangerous situations even if in practice it does not prove to be totally reliable from a safety point of view for the following reasons:

• Non-conductive objects typically cannot be detected;

• Even if small but conductive objects are not always detectable;

• the system must be inhibited in the last closing section to allow the gate to close, otherwise impossible because the stop pillar would be detected as any intervening object and would activate the safety circuit. So in this area, it does not perform any preventive safety functions.

A more sophisticated alternative to guarantee the safety of an automatic gate / door is the installation of optical barriers (infrared - IR) essentially consisting of a receiving unit (RX) and a transmitting unit (TX) of the IR type appropriately aligned. and managed by one or more microcontrollers that implement the signal sending / receiving logic.

Both units (TX and RX) are composed of an aluminum profile (or other material with similar characteristics) with a "U" or similar section, which constitutes the structural support element, inside which the very narrow and elongated rectangular electronic circuit. In many cases, to ensure a good degree of protection for the electronic parts, it is preferred to fill the inside of the profile cavity by pouring with two-component epoxy resin (or similar), leaving only the optical components exposed, which are made to protrude. above the casting level. The TX unit houses a linear array of "n" narrow beam infrared light emitting elements (typically IR LED diodes) suitably spaced, driven by a driver in turn managed locally by a microcontroller which controls the '' operation based on a specific sequential scheme. The RX unit houses a linear array of as many "n" sensors photosensitive to infrared light (typically photodiodes, phototransistors, or similar) spaced with the same geometry as the corresponding elements of the TX counterpart, whose electrical signals, after being suitably filtered , amplified and squared, are examined by a microcontroller which, based on the known scanning protocol and a synchronism signal shared with the TX unit, is able to detect the presence of an obstacle placed inside the barrier itself through the absence of one or more IR signals due to the interruption of one or more light beams. In addition, the RX part normally has at least one wired output, in the form for example clean contact (NO or NC) of a relay, or open collector or sim., which is used to communicate consent (or not) to the drive to the motor control board. Both units (TX and RX) require an externally supplied power supply (normally of the DC type). The objective of the optical barriers is to detect the possible presence of foreign bodies in the handling area without physical contact: these optical barriers can be installed on a fixed or mobile location.

In the latter case, especially due to the relatively high current absorption of these devices, they cannot be powered by batteries (except for batteries that are disproportionate in weight and size), therefore it is necessary to have power and communication cables with the motor control card: this necessarily implies the use of expensive “flexible” type wiring able to accommodate the movement of the mobile leaf by lengthening / shortening if necessary. These interconnection systems, in addition to being particularly expensive and requiring a lot of manpower for installation, are poorly reliable as they are continuously subjected to mechanical stresses of traction and bending which, over time, wear down the insulation and the strands of the conductors.

A further disadvantage of the solutions known to the state of the art is that the assembly of this type of sensors on the mobile leaf requires that the height of the barrier corresponds to the effective height of the closing edge which, generally, is never standard, especially in the case of automatic gates.

If with other types of sensors, such as eg. the safety edges previously described, the adaptation of the sensor length is a normal practice because it is possible for the installer to independently cut the edge to the exact size, with current optical barriers this operation is not allowed.

In the case of installation on a fixed location, on the other hand, two pairs of optical barriers are required to ensure safety in both directions of the automatic door / gate crossing, with a consequent significant increase in costs of both materials and labor for installation.

The main advantage of an optical barrier lies in the fact that it is preventive, that is, it does not require the risk situation to materialize to detect it, and furthermore, due to its intrinsic characteristics, it avoids the further installation of photocells. On the other hand, the inevitable presence of power cables (given the relatively high energy consumption of the optical components) and control cables (for the exchange of the synchronism signal between RX and TX) are the main disadvantages of this solution. In this regard, it should be noted that there are also some types of optical barriers without the aforementioned synchronism wiring, because they exploit algorithms for extrapolation of the sync signal based on the infrared pulses emitted and received. However, even the latter cannot do without power cables and are also marketed in predetermined fixed sizes, they cannot be cut to size and for this reason in many cases they do not perfectly match the edge of the door / gate.

Finally, in the state of the art, hybrid wireless / IR solutions are also known: conceptually it is the creation of a sensitive edge equipped with an integrated IR optical emitter.

This system consists of a mobile part (to be installed on the primary edge of the sliding door) and a fixed one: the mobile part includes two emitting units placed at the ends of an extruded rubber profile and a transceiver placed in an intermediate position.

The fixed part (located on the door stop) consists of a receiver which has the function of communicating with the motor control board and, through special LEDs, to signal the status of the device to the user.

The infrared transmitters, inside the sensitive rubber edge, communicate with the central transceiver consisting of the receiver and the transmitters, which, in turn, is in communication with the fixed receiver. The interruption of the light beam between the emitter and receiver, on the moving part, following an impact on the deformable profile, or the interruption of the light beam between the mobile transceiver and the fixed receiver causes the intervention of the safety edge.

The units that make up this type of solution are battery powered.

The main disadvantage is that this system does not prevent impact / crushing, given the presence of only one horizontal infrared light beam, as in the case of classic photocells. Also in this case, as for normal electromechanical or resistive edges, it is necessary to measure the impact force to verify that it falls within the limits set by the specific legislation.

The purpose of the invention, which is the subject of the present patent application, is therefore to provide a safety device which is effective in preventing impacts or crushing by moving elements, in particular gates, doors and the like and at the same time can be powered by units of the type battery independent from the mains.

In particular, the invention object of the present patent application consists of an optical barrier (3) of infrared light (IR) that can be installed on the moving part of an automatic gate and / or door (1) which does not require the presence of wiring or for the power supply, nor for the communication / synchronism on the mobile part which, being of the wireless type, is of low energy consumption thus guaranteeing battery life and size at a reasonably acceptable level.

The invention which is the subject of the present patent application is shown in the attached Tables in which:

Fig 1: Example of a preferred embodiment of application of the invention which is the subject of the present patent application;

Fig 2: Functional block representation of the invention which is the subject of the present patent application;

Fig 3: Example of a preferred embodiment of the invention which is the subject of the present patent application: front and side view;

Fig 4: Example of a preferred embodiment of a segment of the printed circuit (pcb) of the invention and relative arrangement of the components and of the tracks; With reference to the attached Tables, the safety device object of the present patent application comprises at least one receiving optical unit (1, Fig 1,2,3) and at least one transmitting optical unit (2, Fig 1,2,3).

In particular, as evident in Fig 2, the at least one emitting optical unit (2) is equipped with a linear array of "n" IR emitters (d1, d2, ... dn), preferably but not exclusively of the LED type, suitably spaced between them, and of at least one sensor / receiver (left), preferably but not exclusively of the IR type or other wireless technology (eg RF).

The at least one optical receiving unit (1) is equipped with a linear array of "n" IR sensors (s1, s2, ... sn), preferably but not exclusively of the photodiode, phototransistor or dedicated integrated circuit type, suitably spaced, and of at least one emitter / transmitter (right), preferably but not exclusively of the IR LED type and in any case of the same wireless technology as the corresponding sensor / receiver (left) present on the counterpart.

In addition, the at least one receiving optical unit (1) and the at least one transmitting optical unit (2), are both equipped with an integrated microcontroller / microprocessor (9, 10) which governs their operation through appropriate firmware programming.

With reference to Figure 1, in a preferential but not exclusive embodiment, the emitting optical unit (2) is associated with a fixed element, typically consisting of the stop.

With reference to Figure 1, in a preferential but not exclusive embodiment, the receiving optical unit (1) is associated with the lateral end of the sliding element; moreover the receiving optical unit (1) is equipped with at least one or more cells / batteries (5) which can / can be non-rechargeable or rechargeable by means of special photovoltaic cells associated with the mobile element (1 ).

In general, regardless of the preferred embodiments, the at least one receiving optical unit (1) and the at least one emitting optical unit (2) are positioned in front of each other so that all sensors (s1, s2,… sn) of the at least one receiving optical unit (1) are optically aligned with the corresponding emitters (d1, d2,… dn) of the at least one transmitting optical unit (2).

According to the embodiment described, between the at least one emitting optical unit (2) and the at least one receiving optical unit (1) an optical barrier (3, Fig 2 and 3) is created consisting of "n" beams of IR light suitably pulsed and scanned on the basis of a sequence shared in the programming of the microcontrollers (9) and (10) and suitably synchronized.

In particular, the at least one optical receiving unit (1) comprises at least one emitter / transmitter (right) arranged in such a way as to periodically transmit the digital information of synchronism and status of the barrier, preferably but not exclusively in the form of a serial protocol. suitably modulated infrared (IR) light, or other wireless channel (e.g. via RF).

Corresponding to the at least one emitter / transmitter (right), the at least one optical transmitting unit (2) comprises at least one sensor / receiver (left), which periodically receives the aforementioned digital information of synchronism and status of the barrier from at least one optical receiving unit (1).

According to the system implemented on the basis of what has been previously described, the emitting optical unit (2) will be powered via cable (8, Fig 2 and 3) from the motor control unit (7, Fig 1) of the mobile element while the optical unit receiver (1) associated with the mobile element is powered by the at least one cell / battery (5).

With reference to Fig. 2, the at least one optical receiving unit (1), associated with the lateral end of the movable element is equipped with at least one device (4) for determining the state of rest or movement of the movable element, said device (4) being preferably but not exclusively of the "MEMS" integrated accelerometer type.

According to the invention described above, the transmitting optical unit which, compared to the receiving optical unit, involves a greater absorption of current, is therefore mounted on the fixed part and therefore can be powered via cable.

Consequently, the transmitting optical unit also incorporates the communication interface via cable (8) or other suitable transmission medium, with the motor control board (7), thus limiting the current consumption of the mobile element to the maximum.

Furthermore, again according to the invention, object of the present patent application, thanks to the signal obtained from the at least one motion and / or acceleration sensor (4), it is possible to implement via firmware strategies which totally / partially deactivate the optical barrier (3 ), or make it work at a reduced scanning frequency during the "quiet" state of the mobile leaf, thus preserving the duration of the at least one battery / battery (5) without thereby compromising the effectiveness of the invention as a safety device in accordance with the mandatory technical regulations.

Once the movement status of the mobile element is detected by means of the device (4), the microcontroller (9) in the order:

- Transmits the synchronism / status signal (6) to at least one emitting optical unit (2) through at least one emitter / transmitter (right);

- Starts the scan sequence of the IR sensors (s1,…, sn);

- At the end of the scan, it updates the status of the barrier and transmits it to at least one emitting optical unit (2) restarting the cycle starting from the first point;

In turn, the microcontroller (10) of the at least one sending optical unit (2) in the order: - Receives the synchronism / status signal (6) from the at least one receiving optical unit (1) via the at least one sensor / receiver (left);

- Starts the activation sequence of the emitters (d1,…, dn);

- At the end of the scan, the cycle is repeated returning to the first point to receive the synchronism signal and status update (barrier interrupted / not interrupted) on the basis of which the consent / stop signal is generated which reaches the control unit of the motor via the fixed wiring (8).

However, in order to guarantee the self-test functions envisaged by the mandatory technical regulations, the synchronism / communication channel (6) via the at least one emitter / transmitter (right) and the at least one sensor / receiver (left) is always kept in function, even when the light curtain is partially deactivated or works at a reduced scanning frequency because the mobile leaf is in a quiet state. On the basis of this operating logic, if the microcontroller (10) of the at least one emitting optical unit (2) does not receive the synchronism signal via the at least one receiver (left) within a predetermined maximum time (Timeout), it commands the engine stop (7).

The main advantages of the invention which is the subject of the present patent application can therefore be summarized as follows:

- High level of safety: since the object found is a safety device that totally prevents contact between the moving leaf and any intervening objects / people, the entire automation system of the door / gate does not require the evaluation of the force of impact according to the mandatory legislation;

- Battery power supply of the at least one optical receiving unit (1), installed on the edge of the sliding door, ensuring a good duration thanks to the low-power strategies implemented both at the hardware level with the sensor (4) and with a microcontroller (9 ) ultra low power type, and firmware, in order to reduce the current absorption as much as possible;

- Absence of synchronism / communication wiring between the at least one optical receiving unit (1) and the at least one optical transmitting unit (2) as a wireless communication system is implemented by means of infrared light pulses (6) in the opposite direction than the barrier itself.

- The wireless channel (6) used for synchronism / communication between the at least one optical receiving unit (1) and the at least one optical transmitting unit (2) if implemented preferentially but not exclusively with the IR technology is for its nature, totally immune to low / high frequency electromagnetic environmental disturbances, unlike other RF wireless systems.

- Furthermore, thanks to the measures adopted on the layout of the printed circuit board (pcb), it is possible for the installer to cut transversely both the transmitting optical unit and the receiving optical unit, in correspondence with specific predefined and coincident cutting points on both units, to best adapt the length according to specific needs. This characteristic is obtained in the design phase of the printed circuit layout, by grouping as much as possible the electronic components on the board (13 Fig. 4) around each emitter (d1, ..., dn) and sensor (s1, ..., sn ) in order to leave sectors of pcb (14 Fig. 4) free from components, to allow cutting of the finished product, without damaging the useful electronic parts. Furthermore, in correspondence with the aforementioned cutting areas, the printed circuit tracks (pcb) have been placed exclusively in a direction perpendicular to the cut itself and spaced as much as possible with respect to each other (14 Fig. 4) , also through the alternating arrangement of the same on different layers of the printed circuit (pcb) in order to maximize the isolation.

The system that is the subject of this patent application also meets the requirements of the mandatory technical standards and regulations regarding safety devices for automatic doors and gates, thanks to the use of integrated hardware watchdog systems and the implementation of periodic self-test firmware routines, which also involve checking the operation of the sensor (4).

The invention which is the subject of this patent application, in order to satisfy the requirement of low consumption and therefore guarantee an acceptable duration and dimensions / weight of the at least one cell / battery (5), uses, inside the at least one optical receiving unit ( 1), an "ultra-low power" microcontroller (9) capable of managing various operating modes with reduced or deactivated clock, to optimize current absorption. The operating modes managed by the firmware of the microcontroller (9) of the at least one optical receiving unit (1) are essentially two and are determined by the signal (digital or analog) generated by at least one sensor (4):

� SLEEP MODE: mobile leaf at rest (closed or open), sensor output (4) below the intervention threshold:

� microcontroller (9) placed in "low power mode" with reduced clock, it is periodically awakened ("wake-up") (Twakeup) by means of an interrupt generated by an internal timer;

� periodic transmission (every Twakeup) of one or more synchronism / status bytes through the infrared serial communication channel (6);

ACTIVE MODE: sliding door (1) in motion, sensor signal (4) above the intervention threshold:

� microcontroller running at normal clock;

Sequential activation of all sensors (s1,… sn) and sending of the sync / status signal through the IR communication channel (6);

� if even just one of the sensors (s1, ... sn) does not receive the corresponding IR pulse emitted by the at least one transmitting optical unit (2), the subsequent sending of the sync / status byte (6) will contain the message " state of alarm ";

� The at least one transmitting optical unit (2), if it does not receive the sync / status signal (6) within the predetermined time Ttimeout <100ms, still generates the condition of "engine stop (7)".

It is also possible to modulate in real time the power of the optical emission of the emitters (d1, ..., dn) of the at least one transmitting optical unit (2), by means of a current regulation hardware system, according to the distance between (1) and (2), in order to satisfy the constraints on the geometry of the IR light beam imposed by specific technical standards.

The infrared pulses of the barrier (3) emitted by the at least one emitting optical unit (2) can be modulated, preferentially but not exclusively, by means of a carrier (e.g. square wave) at 36 or 38kHz depending on the type of sensors ( s1,…, sn) used, in order to ensure greater robustness of communication and immunity to disturbances (such as for example sunlight and / or CFL lamps).

Claims (15)

CLAIMS 1) System for the generation of a battery-powered wireless safety light curtain for application to automatic sliding gates / doors said gate / automatic door being made up of a fixed element and a mobile element, said mobile element being associated with a motor (7), said system comprising at least one receiving optical unit (1) and at least one emitting optical unit (2) and characterized in that: the at least one emitting optical unit (2) is equipped with a linear array of "n" IR emitters (d1, d2, ... dn) suitably spaced between them and at least one sensor / receiver (left), the at least one receiving optical unit (1) is equipped with a linear array of "n" IR sensors (s1, s2, ... sn) suitably spaced between them and at least one emitter / transmitter (right), the at least one receiving optical unit (1) and the at least one transmitting optical unit (2) are positioned in front of each other so that all sensors (s1, s2, ... sn) of the at least one unit receiving optics (1) are optically aligned with the corresponding emitters (d1, d2,… dn) of the at least one emitting optical unit (2). 2) System as per claim 1 characterized by the fact that the at least one sensor / receiver (left) of the emitting optical unit (2) is an IR sensor. 3) System as per the previous claims characterized by the fact that the at least one emitter / transmitter (right) is of the IR emitter type. 4) System as per the previous claims characterized by the fact that the receiving optical unit (1) is associated with the mobile element of the gate / automatic door. 5) System as per the previous claims characterized in that the receiving optical unit (1) is powered by at least one battery or battery (5). 6) System as per claim 5 characterized by the fact that the at least one battery or battery (5) is housed inside the receiving optical unit (1) itself. 7) System as per the previous claims characterized by the fact that the at least one optical receiving unit (1) is equipped with at least one sensor / transducer (4). 8) System as per claim 7 characterized in that the device (4) consists of an integrated MEMS accelerometer. 9) System as per the previous claims characterized by the fact that the at least one optical receiving unit (1) is equipped with an integrated microcontroller / microprocessor (9). 10) System as per the previous claims characterized by the fact that the at least one battery / battery (5) can be of the rechargeable type using photovoltaic cells also associated with the mobile element (1). 11) System as per the previous claims characterized by the fact that the at least one emitting optical unit (2) is associated with the fixed element of the gate / automatic door. 12) System as per the previous claims characterized by the fact that the at least one emitting optical unit (2) incorporates the communication interface with the motor controller (7) via cable (8). 13) System as per the previous claims characterized by the fact that the at least one optical transmitting unit (2) is equipped with an integrated microcontroller / microprocessor (10). 14) System as per the preceding claims characterized by the fact that on the at least one optical transmitting unit (2), the printed circuit is designed in such a way as to leave areas (14) free from electronic components, within which the tracks are traced longitudinally with respect to the printed circuit. 15) System as per the preceding claims characterized in that on the at least one optical receiving unit (1), the printed circuit is designed in such a way as to leave areas (14) free from electronic components, within which the tracks are traced longitudinally with respect to the printed circuit.