EP2146034A1

EP2146034A1 - Safety device for a gate or for a sliding door actuated by a motor

Info

Publication number: EP2146034A1
Application number: EP09164704A
Authority: EP
Inventors: Fabio Billo
Original assignee: BFT SpA
Current assignee: BFT SpA
Priority date: 2008-07-16
Filing date: 2009-07-07
Publication date: 2010-01-20
Also published as: ITVI20080170A1

Abstract

A safety device for a gate or sliding door, actuated by a motor (7) is made up of a reflection photoelectric device (17), controlled by a pilot circuit, of a pressure sensitive bar (14) applied to the sliding wing (2), said bar comprising a reflector mirror, equipped with a shutter and a mobile part. Said safety system is characterized in that a force exerted on the mobile part of said sensitive bar, causes the shutter to close by intercepting the radiation (22), emitted by the transmitter of the photoelectric device (17) and stopping the reflection on the surface of the mirror in the direction of the receiver of the photoelectric device (17), sending through the pilot circuit, a signal to the control unit (8) of the actuation motor (7).

Description

The present finding regards a safety device for a gate or for a sliding door actuated by a motor, according to the general part of claim 1.
The application standard of recent European directives in the field of automated doors and gates, in particular the machinery directive and its application standard EN 13241-1, obliges the manufacturer of a motorized door to install accessories having the purpose of preventing or reducing the effects of bumping into or squashing people, animals or things in the manoeuvring radius of the wing. The same standard requires at least one photocell device to be installed, in many installation conditions. In common use pairs of photocells are applied, installed onto the pillars of the access opening of the gate or door, on its inner or external part and at variable heights depending on the use of the door. The mechanical safety of the system towards the user or public, who enter the manoeuvring area of the door, is not however sufficiently ensured by the photocells alone. Indeed, their intervention covers only the portion which joins the transmitter with the receiver, leaving the area above and below said portion without protection. For this reason the European and international standards prescribe additional measures, as the installation of one or more pairs of photocells for detecting the presence of people or objects, is not a measure considered sufficient in itself to ensure the safety of a system, in particular in the cases in which the manoeuvring area can be accessed by the public and the users are not sufficiently trained to use it. For example, it is foreseen for it to be possible to apply, in combination with the device for detecting the presence of people or objects made up of a pair of photocells, one or more devices, sensitive to the pressure exerted by the obstacle on the mobile part of the wing, which intervene when the edge of the wing is already in contact with the obstacle, with the function of reducing the negative effects, making them stop or inverting their movement. A required characteristic is that of limiting the instantaneous forces which develop during the impact of the wing against an obstacle and that within a short time after the impact, the force still acting upon it drops to a very low value, typically lower than 25N. In some constructive solutions proposed by the industry operating in the field of these products, these devices are integrated in the control unit, being sensitive to one or more variables indirectly connected to the pressure exerted by the obstacle onto the wing, for example, the current absorbed by the geared motor or the rotation speed of elements of the reduction group. Alternatively, pressure sensitive devices are applied directly to an edge of the wing to be protected, connected to the control unit of the motor and supplied with power by cable. The mechanical action of an obstacle on the deformable part of the device has different effects: the most common solution closes a contact through a microswitch actuated by a cable extending along the profile, or it activates a pressure switch inserted in an air-tight volume formed inside the profile, or it obstructs a light beam inside a chamber which develops in the length of the profile, or it puts into contact two electrically conductive strips, positioned inside the profile, arranged in parallel with a high value resistance (generally 8.2 kOhm). If the weight or the manoeuvring speed of the wing is high, limiting the forces within the limits foreseen by the reference standard, they can be a problem for a system integrated in the control unit of the motor. In this case the application of a non-integrated protection is a forced choice. These devices have a shorter response time and the sensitive element is made up of a programmed deformation profile, sufficient to dissipate most of the kinetic energy and to invert the movement before the forces applied to the obstacle reach excessive values. Many of the existing products on the market need a different operating logic to activate depending on whether the signal received by the gate or door control device is relative to the activation of the photocell or to the occurrence of an impact. This is essentially determined by the fact that devices for protecting against impact, which operate based upon the deformation of a profile, normally in rubber or other similar material, are not able, due to the reaction of the material to the deformation, to ensure that the prescriptions of the standards regarding residual force after impact are respected and therefore require a movement inversion of the gate, so as to nullify said residual force.
Since the movement of the wing is a sliding movement with respect to fixed parts, it is necessary to foresee connection means which, in the state of the art, are expensive, complex to install and ugly. The cables can be of the extensible type (for example, coiled cables), which are simple, not very expensive but are ugly and at times also unreliable, since they are used in outdoor conditions, or sliding connecting systems are applied, which are complex, not very reliable and expensive.
Some solutions have been proposed to avoid this drawback: for example, radio or optical transmission systems are commonly adopted to allow an obstacle detecting signal to be sent to the control unit.
In the publication EP 1 529 913 a safety system for motorized gates is described, made up of a transmitter able to generate an infrared signal applied to the mobile wing and connected to a sensitive rib; coupled with a receiver which is applied to the fixed part and connected to the control unit of the system. In the case of normal operation of the gate, the infrared signal emitted is continuous, but in the case, in which the bar is activated by a pressure exerted by an obstacle, the emission is interrupted and this is translated into a stop command of the manoeuvring motor. The system thus has the advantage of freeing the installation of the need of cables, but forces the user to periodically replace the batteries for supplying the pilot circuit of the rib, which, not being supplied with power by any conductor, needs an internal power source.
In the publication W006051 060 a safety system is described that implements the same principle with a signal transmission protocol which optimizes the energy consumption of the transmitter and its pilot circuit, by varying the transmission frequency according to the status of the actuation motor and increasing in this way the lifetime of the battery. This solution reduces the frequency with which the batteries need to be replaced, but it does not solve the problem definitively.
In the publication EP 1 739 265 a safety system is described made by a pair of receivers-transmitters, in which a fixed element of the pair is supplied and connected to the control unit of the motor through cable, whereas the mobile element fixed to a sliding wing is supplied by a photodiode which exploits the radiation emitted by the fixed element to charge an internal battery and it is connected to the active ribs fixed on the same wing. The efficiency of the transmission varies according to the distance between transmitter and receiver, making the case in which the user needs the door to remain open over long periods, problematic.
The purpose of the present finding is that of making an apparatus for rendering safe a gate or a motorized sliding door that satisfies the standard requirements and eliminates the drawbacks of the solutions listed above. In particular, the solution definitively eliminates the need to supply the mobile element with any kind of energy, combining the function of detecting the presence of people or objects along the manoeuvring trajectory of the gate, with that of detecting the pressure exerted on the profiles of the wing by an obstacle, freeing the installer of the need to use mobile electric connections and of having to periodically replace the power supply battery; all of this without a substantial increase in cost.
These and further advantages of the present invention shall become clearer with the help of the attached drawings, to be considered as a practical example embodiment, and should not for this, limit the solution. In particular:

fig. 1 (table I) represents a general view of an automation system of a sliding gate, with an example of application of the safety system;
fig.2 (table II) represents a top view of the same automation system with some further developments;
fig.3 (table III) represents a longitudinal section of the scheme for making the actuation mechanism of the reflector mirror on the mobile element according to the pressure exerted on the sensitive bar by an obstacle;
fig.4 (table IV) represents the anchorage between the mobile part and the pantograph arms;
fig.5 (table V) represents a top view of the system, in the case in which the applied force has a perpendicular component to the movement of the gate.

In the present description we shall refer to a horizontal sliding gate, but of course this is only one of the possible developments of the idea which can be applied to other types of applications.
Figure 1 represents an access opening 1 closed by a wing 2 of a gate 3; said wing, runs on wheels along a track 4, between two fixed parts 5 and 6, into the open and closed position. The gate is actuated by a geared motor 7, which integrates a control unit 8 and a radio frequency receiver 9 and it is controlled by a radio control 10, or by one or more wired fixed controls 11. The system can be equipped with a signal light 1 2 and with a pair of photocells 1 3 applied on the fixed side parts. The implementation described here of the object of the present finding consists of a pressure sensitive bar 14, made up of a mobile element 15, coupled with a base profile 1 6 fixed to the edge of the gate and of a photoelectric device 17 consisting of a transmitter element 18, of a receiver element 19 and of a pilot circuit 20, in turn connected with the gate control device.
In the mobile element 1 5 of the pressure sensitive bar 14, opposite to the photoelectric device 17, an opening 21 is formed for the ray 22, emitted by the transmitter of the aforementioned device to pass through, up to a reflector mirror 24, consisting of at least one preferably polarizing element, positioned in a compartment 25 of the mobile part 15. Fig. 2 represents in the top view, the ray 22, sent from the photoelectric device 17 and the ray 23 reflected by the mirror 24 and consisting of an optical radiation, preferably polarized perpendicularly with respect to the emitted ray 22. The polarization allows noise reflection to be eliminated on other parts of the wing and the radiation which is reflected by the mirror to be distinguished from this noise. Figure 3 represents the compartment 25 in which the mirror 24 is positioned, that is preceded by a shutter 26, consisting of one or more tilting elements 27, fixed at the sides of the casing to a mobile bracket 28. When the shutter 26 is open, the mirror reflects the ray 22, generating the optical signal 23 in the direction of 17. When there are no obstacles at the access opening, the receiver 19 of the device 17 receives the optical signal 23 and the safety device status is in stand-by: the motor can start or continue the actuation of the gate wing in the two directions of opening and closing.
In the opposite case, the interposition of an obstacle at the access opening or the presence of a significant force exerted on the mobile element 1 5 of the pressure sensitive bar 14 determine the closing of a shutter 26, located in front of the polarizing mirror, blocking the ray 22 and the ray 23, translating the missed reception in the receiver 19 into a suitable signal sent from the pilot circuit 20 of the photoelectric device to the control unit of the geared motor 8 to carry out suitable instructions to ensure the safety of the installation, like, for example, the stopping and/or inversion of the wing movement.
Fig. 3 represents the seat element 25 of the polarizing mirror 24; it can also be seen that the shutter, in the open position, consists of at least one tilting blocking element 27. There is also a mobile side bracket 28 to which said element 27 is fixedly connected, an actuation cable 29 of the shutter 26, connected to the mobile element 15 of the pressure sensitive bar 14, at least one reaction spring 30 between the mobile and fixed element of the profile and a hook 31 for joining the mobile element to the fixed element 16. As it can be seen in the figure, the rotation of the tilting elements 27 occurs along a right angle, from an upper horizontal position which opens the shutter, to a lower vertical position, which completely closes the shutter instead. The force exerted on the mobile element 15 of the pressure sensitive bar 14 releases the cable 29 thus allowing, thanks to the force of gravity, the tilting elements 27 of the mirror 24 to rotate freely, therefore closing the shutter 26, intercepting the ray 22 and generating a signal for carrying out suitable instructions to ensure the safety of the installation, like for example, the stopping and/or the inversion of the wing movement.
The breaking of the connection cable 29 between the mobile element 15 and the shutter 26 also causes the shutter to close, due to the falling of the blocking elements 27, thus protecting the system from possible failures or breaking of the cable 29.
In order to operate correctly, the mobile element 15 of the pressure sensitive bar 14 must always move parallel to its fixed part 16 and this is ensured by the pantograph system formed by the elements 32. Said system has a particular configuration, which, during the installation and manufacturing steps of the pressure sensitive bar 14, allows the mobile element to be assembled with and disassembled from the fixed one, by simply moving it to its maximum stroke, so that the shaped pins 33 come out of the seats 34, that are suitably sized to allow the pins 33 to come out, when they are oriented in a way corresponding to that of its maximum stroke.
A grasping system 31 stops the pins from coming out from the seats during normal use.
In addition to the configuration described hereby, there is no reason why a pressure sensitive bar 14 cannot be used also on the fixed parts, for example, to protect the shearing and conveying points which are created between the pillar and the sliding wing. It is also possible to protect the secondary edge of the wing by applying a second pressure sensitive bar on the side opposite from that of the opening movement of the wing.
These examples are illustrated in fig.2, which represents a top view of an installation, in which the described protection device is applied at various risk points identified during the installation.
In general it should be stressed how the particular implementation described above, whilst operating, combines the characteristics of a photocell, in which the interception of the ray is sufficient for a certain behaviour of the gate or automatic door and the characteristics of a pressure sensitive bar, in which a force exerted on any point of its mobile element causes the execution of suitable instructions to ensure the safety of the installation, like for example, the stopping and/or inversion of the wing movement.
It is a special feature of the present invention that it is possible to obtain a very low residual force at the end-stop, with a value below the minimum allowed by the standards currently in force, equal to 25N. In this case, the standards themselves allow the same response to be obtained in terms of behaviour of the gate or motorized door, both when it receives a photocell intervention signal, and when it receives an operative force limiting intervention signal due to the bumping against an obstacle. In this case the advantage of the present finding is obvious, since the number of connections and the complexity of the logic implemented in the automation is much lower in the case in which the photocell and the operative force limitation signals coincide.
In other installation situations it may be desired to not have the transmitted radiation and the reflected radiation crossing the through opening of the gate, so as to only be able to have the signal in the case of an impact and not when passing through the gate. In this case an implementation is possible in which the transmitter and the receiver of the signal are located near to the actuator which moves the gate and the reflector is placed at the side of the bar, oriented towards the actuator.
Said implementing situation is shown in fig. 2, where the photoelectric device 17 is installed at the side of the actuator 7 with the transmitter and the receiver oriented so as to send and receive a signal in the direction of the reflector, since it is in front of the shutter, which is actuated by the movement of the mobile element of the pressure sensitive bar which determines the slackening of the tension of the wire and, through the weight, it determines the closing of the shutter.
In practical use there may be an impact with a vehicle or with other mobile objects and this impact can cause a substantial force component perpendicular to the movement of the mobile part 15 of the pressure sensitive bar 14. In this case it could suffer damage; in order to avoid this drawback, the making of the device, object of the present finding, foresees joint elements 32 between the fixed part 16 of the pressure sensitive bar 14 and the point in which it is fixed. This is shown in detail in fig.5. When a force F35 acts with a component 36 transverse to the movement of the mobile part 15 of the pressure sensitive bar 14, the springs 30 allow the translation of the entire pressure sensitive bar 15, so as to reduce the effect of the force 35 itself. As an additional result, an immediate misalignment is obtained between the reflector 24 and the receiver 19, with a consequent immediate signal to the control unit 8 of the motor of the gate or door 7.
The present implementation is relative to an interruption system of the reflected ray due to the intervention of a shutter, but similar performance can be obtained with systems which foresee, in case of intervention, the shifting of the reflected ray, through the shifting, rotation, covering of the reflector or through other similar measures.
The embodiment of the finding can vary as far as the shape, sizes, materials and configuration of the various elements are concerned, without for this reason departing from the adopted idea and therefore covered by the scope of protection granted by the present patent.

Claims

1. SAFETY DEVICE FOR A GATE OR FOR A SLIDING DOOR (3) ACTUATED BY A MOTOR (7), made up of:

- a photoelectric device (17), positioned on the fixed side of the access opening (1), in opposition to the wing of said gate or door (2) and made up of a receiver (19) and transmitter (18) of radiation or of a signal;

- a pressure sensitive bar (14), made up of a fixed part (16) applied along the profile of the wing of said gate or door (2) and of a mobile part (15);

- a pilot circuit (20), which controls said photoelectric device (17) and which is connected to the control device of the actuation motor of the door or gate (3);

- a reflector mirror (24), able to reflect the radiation or signal (22) generated by the transmitter (18), towards the receiver (19), said reflector (24) being fixed to the wing of the gate (2) directly or through parts of said sensitive bar (14) and equipped with a shutter (26),

The device being characterized in that a force exerted on the mobile part (1 5) of said sensitive bar (14) causes or allows said shutter (26) to close, intercepting the radiation (22) emitted by said transmitter (18), stopping or limiting the reflection on the surface of said mirror (24) in the direction of the receiver (19) which, through said pilot circuit (20), sends a signal to carry out instructions suitable to ensure a safe installation to the control unit (8) of the actuation motor (7).

2. DEVICE, according to claim 1, characterized in that the pilot circuit (20) sends a signal to stop the actuation motor (7), to the control unit (8).

3. DEVICE, according to claim 1, characterized in that the pilot circuit (20) sends a signal to stop the actuation motor (7) and to subsequently reverse the motion, to the control unit (8).

4. DEVICE, according to one or more of the previous claims, characterized in that the reflector mirror (24) polarizes the reflected radiation (23) on a plane substantially perpendicular to the plane in which the radiation is emitted by the transmitter (18), the receiver being polarized in turn on a plane perpendicular to the signal sent by the transmitter.

5. DEVICE, according to one or more of the previous claims, characterized in that the sensitive bar (14) is also able to be applied to the secondary profile (43) wing of the gate or door (3), to protect the movement area of the wing (2) along the perimeter (44) adjacent to the access opening.

6. DEVICE, according to one or more of the previous claims, characterized in that the sensitive bar (14) is able to be applied between a pair of fixed parts (6) at the side of the access opening (1).

7. DEVICE, according to one or more of the previous claims, characterized in that the actuation of the shutter (26) is controlled by a cable (29) connected to the deformable part of said sensitive bar (14), so that when the cable is broken, it makes the shutter close.

8. DEVICE, according to one or more of the previous claims, characterized in that the shutter is made up of at least one blocking element (27), connected to a side bracket (28), actuated by a cable (29), so that the rotation of said shutter from the horizontal open position to the vertical closed position occurs by gravity.

9. DEVICE, according to one or more of the previous claims characterized in that it foresees pantograph arms connected to the fixed part (16) through joint elements (32), which allow translation (37) of the deformable part of the bar (15) perpendicular to the movement of the gate, in order to reduce the effect of one of the components (36) of the force (35) applied.