FR2513301A1 - Optical safety device for motorised roller door - uses electrically operated optical polarisation block on door to discriminate against ambient light - Google Patents

Abstract

The arrangement includes a barrier (1) moving between two pillars( 2,3) and driven by an electric motor (4). The barrier stops the drive motor if an obstacle is detected in the path of the door. The detectors used are an array of light beams and a pneumatic detector. The light beams have a light source (5) and a corresponding light detector (6) mounted on the door pillars (2,3). An opto-electronic block (14) is fitted to the door, and is powered by a battery mounted on the door so that can be polarised to permit or block the passage of light. This method gives improved discrimination against ambient light. The pneumatic contact is formed as a rubber edge to the door. Both detectors switch off the drive motor if an obstacle is detected.

Description

 The invention generally relates to motorized sliding gates comprising a barrier displaceable in translation by a motor unit to open and close a passage between two pillars. More specifically, the invention relates to a connection device between an obstacle detector placed on the edge before the barrier and a control unit of the engine group.

 Large gates, especially designed to let utility vehicles through, are often motorized. Motorization implies that safety devices are placed on the gate to prevent maneuvers, especially when closing if an obstacle, person or material, is in the path of the movable part of the gate.

 When the passage, which the gate must release or condemn, is very wide, the generally preferred solution is the gate with a barrier which can be moved in horizontal translation, the extent of which in the direction of the passage is reduced substantially to the thickness of the barrier. , which imposes reduced constraints on the pillars which delimit the passage, these pillars not forming an anchor point for the motorization. Furthermore, the passage width served by a mobile part is almost arbitrary if this part is mobile in horizontal translation.

 Safeties against the presence of an obstacle in the path of the movable barrier of a portal with horizontal translation are commonly of two types, a light beam barrier arranged across the passage between the pillars, and an obstacle detector disposed on the front edge of the generally pneumatic movable barrier. The latter type of security comprises a flexible tube extended over the height of the edge, closed at its ends, and connected to an electrical contact controlled by a capsule ~ pneumatic. The crushing of the tube against an obstacle creates an internal overpressure which comes to operate the electrical contact. It will be noted that this type of security complements the light beam barrier which acts at a distance, but only when the obstacle cuts the beam, while the obstacle detector acts on contact with an obstacle which has escaped the beam.

But the obstacle detector security, which acts in re
response to a collision at any point of the song, and which plays
in addition a damping role, is necessarily united with
the movable barrier, and must be coupled to the control box
of the motor unit, fixed, by a connecting device which supports
te the linear displacement of the barrier. We used, for the
electrical connection, flexible cables and rail pairs
wipers. This last solution poses problems of reliability
a series of rubbing contacts exposed to the weather. Cables
flexible, so as not to risk dithering on the route
of the barrier, be hung in festoons on neck supports
straighteners, or be fitted with cable reels.
are exposed to breakage or breakage, especially if the
bad weather, especially snow or frost, impede the
sliding festoon supports, or re-functioning
gulier reels.

An intangible link between the electrical contact of the
pneumatic sensor and the mo group control box
tor removes the difficulties associated with rubbing contacts and
to flexible cable connections. However an intangible bond
rielle would be of illusory interest if it presented in
own conveniences of importance greater than or comparable to
those presented by flexible cable electrical connections
or floating contacts. In particular, an intangible link does not
must not be interfered with by parasites from the environment
reason, and should not require, for the part of device connected to the barrier, a supply energy such that
requires an electrical connection to the sector, which would bring
to the difficulties that are claimed to be eliminated.

However, to ensure a reliable and decoupled connection of pa
environmental rasites it is desirable that this liai
sound is directed, and operates at a high signal-to-noise ratio.

Practically the acoustic and hertzian connections are ex
clues.

To solve the above problem, the invention
offers, in a portal with a movable barrier in
translation under the pressure of a power unit to open or
close a passage between two pillars, with safety devices coupled to a control unit of the engine group to stop the translation if an obstacle occurs in the passage, these safety devices comprising a light beam barrier with a transmitter and a receiver mounted on the pillars, and an obstacle detector arranged on the edge before the barrier and capable of opening an electrical contact in response to a knock against an obstacle, a device for connecting this contact to the control unit of the engine group characterized in that it comprises an optoelectronic shutter fixed to the barrier, arranged in the path of the light beam, and supplied by an autonomous source of energy integral with the barrier through the contact of the obstacle detector so as to be shutter in response when the contact opens.

 Thanks to this arrangement, which borrows the light beam from the light barrier, in a manner known per se protected against environmental interference, the reliability of the connection between the obstacle detector and the control box is practically that of the operation of the '' optoelectronic shutter; this is powered by the autonomous source of energy, which can form a robust and compact unit, and a high reliability, so that the reliability of the set of safety devices is substantially as high as that of the optical barrier safety device. , normally expected. Furthermore, the energy required for the connection is limited to that which is required by the actuation of the optoelectronic shutter.

 Among the optoelectronic shutters, it is preferable to use a shutter formed by a blade of a liquid crystal material between two electrodes, sensitive to low currents under voltages of a few volts. It is also preferable to use a birefringant liquid crystal shutter between polarizers, this arrangement giving a more frank shutter.

 The autonomous energy sources will consist of an accumulator battery which will be recharged either by a generator with photovoltaic cells, or by a rotating generator coupled to a roller of the barrier.

 Furthermore, in the open and closed positions of the gate, the autonomous sources of energy will preferably be disconnected from the shutter by means of magnetic control contacts arranged on the barrier, and coming opposite fixed electromagnets in the extreme positions.

The characteristics and advantages of the invention will become apparent from the description which follows by way of example, with reference to the accompanying drawings in which
Figure 1 is a representation of a gate equipped with a device according to the invention
Figure 2 is a device diagram according to the invention;
FIG. 3 represents a variant of supplying an autonomous energy source.

 As shown in Figure 1, a gate opening by translation of a barrier 1, includes fixed pillars 2 and 3 which limit the passage. The rear pillar consists of two gantries 3a and 3b which ensure the vertical hold of the barrier 1, and surround a motor unit 4, capable of causing the displacement of the barrier 1 to open or close the passage between the pillars 2 and 3. The barrier 1 is mounted on rollers 11, 12 guided by a rail.

 To avoid accidents during the operation of barrier 1, the gate is equipped with two safety devices. Firstly, a light barrier with a beam emitter 5 mounted on the front pillar 2 (relative to the advance of the barrier) and a receiver 6, coupled to the control unit of the power unit 4, and mounted on the pillar 3. Secondly a pneumatic tube 10 obstacle detector, made of rubber, mounted on the front edge of the barrier 1, and equipped with an electrical contact which changes position when the tube 10 comes to crash into an obstacle. These two types of security are classic in themselves, and complement each other, the light barrier causing the engine unit to stop when, at any point in the passage, an obstacle cuts the beam 5, G, while the flange 10 detector obstacle stops the barrier if it comes into contact with its front edge, an obstacle which is in the path of the barrier, without cutting the light beam. In other words, the obstacle detector 10 is there to act as a backup for the light barrier security.

 The safety devices with pneumatic obstacle detection must obviously be linked to the control unit of the engine group, the electrical connection being practically the only one in use. However, rolling barriers are generally only justified when the passage to be closed is wide; the electrical connection between the pneumatic sensor 10 and the motor group control box 4 involves either a cable which supports the movement of the barrier 1, or contact rails and wipers. Generally, it is risky to use rubbing contacts in a safety circuit. The connecting cable must be protected against accidental snagging and pulling.

 According to the embodiment chosen and shown, there is disposed on the path of the light beam between the emitter 5 and the receiver 6, an optoelectronic shutter 14 fixed to the barrier 1 near the edge before this barrier.

In what follows, reference will be made to FIG. 1 for the locations of the elements on the portal, and to FIG. 2 for the more precise representations of the elements, and their reciprocal links.

 The shutter 14 is constituted by a liquid crystal cell 18 disposed between parallel polarizers 19 and 20, of the kind described in French patent application 2 466 496. The cell 18 is filled with nematic material between two transparent electrodes, the material being polarizing, and the main axes of the molecules, in the absence of current, being arranged so that the plane of polarization of a light beam perpendicular to the faces of the cell rotates 900 while passing through this cell . As the polarizers 19 and 20 are oriented with their main axes parallel, the light beam, as long as no current flows between the electrodes of the cell 18, cannot pass through the whole of the shutter 14. On the other hand, the passage of current in cell 18 causes the molecules of the nematic liquid crystal to align, which no longer causes the plane of polarization to rotate. Then the beam passes through the assembly of the shutter 14.

 This nematic cell arrangement between oriented polarizers gives an excellent transmission contrast between the open and closed states of the shutter.

 The supply of the shutter 14 is obtained by means of an energy source 13 which comprises a battery 16a rechargeable through a circuit 16 such that the charging current adapts to the state of the battery 16a, when the cells photovoltaics 15 are suitably lit, and that there is no discharge current from the battery 16a to the cells 15 which are insufficiently lit.

 The cell 18 is connected to the source 13 through the contact 17a of a pneumatic capsule 17 in communication with the pneumatic detector 10, formed of a rubber rod closed at the ends. It is understood that the crushing of the flange 10 opens the contact 17a. However, there have been arranged in series, between the contact 17a and the cell 18, two flexible reed switches 21 and 23, polarized in closing respectively by magnets 22 and 24. In addition, a powerful electromagnet 25 is disposed at the level of the power unit in the casing 4, so that the magnetic field which it creates is antagonistic to the field of the polarizing magnets. The arrangement is such that, when the barrier 1 is closed, the electromagnet 25 is opposite the switch to flexible blades 23, and, when the barrier 1 is fully open, the electromagnet 25 is opposite the flexible blade switch 21. Thus, at the two extreme positions of the barrier 1, the electromagnet 25 neutralizes the field of the magnet 22 or 24, and the corresponding flexible blade switch is open. At these two extreme positions, where the safety devices do not have to act, the cell 18 cannot be supplied with power, and the battery 16a cannot be discharged.

 When the barrier must leave one or other of these extreme positions, the electromagnet 25 is cut, and the corresponding flexible blade switch 21 or 23 closes; the other switch (23 or 21) being closed, the barrier can be set in motion; when, with the barrier moving, the electromagnet 25 is not facing any of the flexible reed switches 21 and 23, the crushing of the flange 10, opening the contact 17a, cuts the shutter 14, which cuts the light beam between the transmitter 5 and the receiver 6.

 It will be noted that finally the collision of the obstacle detector 10, which comes to the aid of the beam barrier security 5 to 6, has the same effect as an obstacle which cuts this light beam.

 When the location or exposure of the portal or the climatic conditions are unfavorable for the operation of photovoltaic cells 15, these cells 15 can be replaced by a device as shown in FIG. 3, where a pulley 26 secured to the rolling roller 11 drives , by means of a belt, a rotating electromagnetic generator 17 (alternating magnet with magnet) connected to the circuit 16 by means of a rectifier 28. It will be noted that the rotating generator coupled to the roller provides energy mainly when the pneumatic edge safety may have to play.

 As the photoelectronic shutter acts by all or nothing, with an excellent contrast ratio between the open or closed states, it is compatible with all safety devices with light beam barrier, and in particular with devices where the intensity of the beam is modulated in the transmitter 5, the receiver 6 comprising a synchronous demodulator, so as to improve the protection of the device against parasitic signals (lightning, vehicle headlights, public lighting, etc.).

 It will be understood that, although the arrangement described incorporates a pneumatic obstacle detector, simple and reliable, any mechanical obstacle detector can be used as soon as it opens a contact in response to a shock on the edge of the back.

 Of course, the invention is not limited to the examples described, but embraces all the variant embodiments.

Claims (6)

 1. In a portal comprising a barrier (1) movable in translation under the thrust of a motor unit (4) to open or close a passage between two pillars (2, 3), with safeties coupled to a control box of the motor unit (4) to stop the translation if an obstacle arises in the passage, these safety devices comprising a light beam barrier with a transmitter (5) and a receiver (6) mounted on the pillars (2, 3), and a pneumatic detector (10) disposed on the front edge of the barrier (1) and capable of opening an electrical contact (17a) in response to a collision with an obstacle, a device for connecting this contact to the control unit of the engine group (4) characterized in that it comprises an optoelectronic shutter (14) fixed to the barrier (1), disposed on the path of the light beam (5, 6) and supplied by an autonomous source of energy (13) integral with the barrier through the contact (17a) of the pneumatic detector (10) so as to be closed and n response to opening the contact.  2. Connecting device according to claim 1, characterized in that the optoelectronic shutter comprises a blade of liquid crystal material (18) between two electrodes.  3. Connecting device according to claim 2, characterized in that the blade (18) of liquid crystal material is birefringant and disposed between parallel polarizers (19, 20).  4. Connecting device according to any one of claims 1 to 3, characterized in that the autonomous source of energy (13) comprises a generator with photovoltaic cells (15).  5. Connecting device according to any one of claims 1 to 3, characterized in that the autonomous source of energy comprises a rotating generator (27) coupled to a roller (11) of the barrier (1).  6. Connecting device according to any one of claims 1 to 5, characterized in that it comprises magnetically controlled contacts (21, 23) on the barrier, and control electromagnets (25) at locations of the passage such that '' in the gate's open and closed positions, the optoelectronic shutter (14) is disconnected from the autonomous energy source (13).