A SAFETY DOOR WITH A SLIDING PANEL The present invention relates to a safety door with a sliding panel, in particular a raisable door having a panel that can move up and down so as to clear or close a 5 doorway formed in a wall. The panel can be rigid, so as to be raised above the doorway, and possibly tilted towards the horizontal. It can be constituted by a plurality of elements that are stored beside one another above the doorway. The panel 10 can be constituted by a flexible curtain, which can be rolled up or folded up above the doorway. The curtain can be reinforced by one or more horizontal bars, whose ends can be engaged in slideways so as to be held and guided therein. This list is not exhaustive. 15 Uprights can be used to support mechanical elements of the door which are placed above the doorway, or they may merely contain the slideways, i.e. two facing walls between which the edges of the curtain and possibly also the ends of reinforcing bars are received and can move. 20 It is important that some doors should be capable of being opened immediately by some action that is very simple, e.g. in the event of panic, or else to avoid panic. In particular, it has been found most advantageous to be able to trigger the opening of a door 25 merely by exerting pressure on any point of the door. It is thus an object of the present invention to provide a door which opens when pressure is exerted on any point of the door. European patent No. 0 181 268 discloses a safety 30 device for a raisable door in which the door can be held in a closed position by the brake of a brake motor, with manual means enabling the brake to be released, thus providing a door which rises under drive from a counterweight. 35 French patent application FR-2 732 718 describes a safety system for a raisable door, in which the tension in a filamentary element secured to the bottom of the 2 door is monitored by appropriate apparatus that enables a signal to be issued when the tension of said filamentary element drops below a predetermined threshold. Thus, if the door encounters an obstacle as it moves downwards, 5 the filamentary element relaxes and the safety system issues a signal. Nevertheless, that system does not operate when pressure is exerted on the door at the level of the filamentary element. Under such circumstances, it deforms together with the door panel, so its tension 10 remains unaltered. Document US-5 141 044 discloses a door that includes a stop device which prevents the door panel from moving when it escapes from its slideway because of a collision. The force required for actuating the stop device is large 15 and that device is therefore incapable of detecting simple pressure applied at any point on the panel. Document WO 96/24743 discloses a device of the same type. According to the present invention, a safety door of 20 the above type is remarkable in particular in that said door is provided with detector means responsive to thrust exerted at any point of at least one face of said panel, said detector means delivering a signal in the event of such a thrust occurring. 25 Advantageously, the signal acts on means for causing the panel to rise, so as to clear the doorway. According to another advantageous characteristic of the present invention, the means for causing the panel to rise make use of energy that is independent of the 30 ordinary operating energy for the door. The safety door of the invention must be capable of operating so as to allow people to escape under all circumstances, fire, electricity failure, etc. It is therefore advantageous for the safety feature to be 35 capable of operating with energy that is always available independently of existing energy distribution networks (electricity, compressed air, etc.). According to the 3 invention, the energy for raising the door panel can come from a counterweight, a spring, a storage battery, or any other independent system. The detector means sensitive to thrust exerted on 5 any point of at least one face of said panel can be of any kind. Generally, raisable doors comprise a flexible or rigid curtain, and slideways on either side for receiving respective edges of the curtain, possibly together with 10 the ends of curtain-reinforcing bars. In an embodiment of the invention, the slideways include means responsive to force being exerted directly on a slideway, or responsive to force such as thrust applied at any point on the panel and communicated by the 15 panel to at least one of the slideways. In an embodiment, the slideways are movable against resilient means from a rest position, and the door includes means for triggering a signal when the slideway moves away from its rest position. In a variant, the slideways may also 20 be deformable. According to a characteristic of the invention, the panel includes reinforcing means, said means being adapted to transmit to the slideway forces which are exerted on the panel. 25 In an embodiment of the invention, the reinforcing means are lateral reinforcements of the panel co operating with the slideways, e.g. the slideways have edges adapted to retain said lateral reinforcements if they are urged so as to escape from the slideway, due to 30 thrust being applied to the panel. In another embodiment of the invention, the reinforcing means are transverse rigid elements such as at least one horizontal bar having at least one end capable of sliding in a slideway. 35 Thus, such a door makes it possible, where necessary, to obtain a signal merely by applying pressure to the panel or to one of its slideways. The signal can 4 be an audible or luminous warning signal or it may trigger any operation such as raising of the panel by means of a motor, or under drive from a counterweight, or a spring, or some other means (a battery, etc.), the 5 signal-issuing means may be of any kind such as mechanical, electrical, electronic, pneumatic, hydraulic, etc. The energy necessary for raising the door in response to such a signal is preferably different from 10 the energy which actuates the door in normal operation. Other characteristics and advantages of the invention appear from the following description given by way of non-limiting example and with reference to the accompanying drawings, in which: 15 - Figure 1 is a front view of a door of the invention; - Figures 2, 3, and 4 are detail views of an example of means for issuing a signal in accordance with the invention; and 20 - Figure 5 is a variant view of a detail of the invention. The figures show an advantageous embodiment of the invention in which any force exerted on the panel is transmitted to a slideway, and it is the slideway which 25 includes means for issuing a signal. Nevertheless, the invention is not limited to that particular embodiment, and other detector means responsive to thrust exerted at any point on the door panel can be envisaged (detecting deformation of the 30 panel, pressure sensors on the panel, etc.). In Figure 1, a door is placed against a wall 1 to control the opening and closing of a doorway. The door has two lateral uprights 2, 3, and a top cross-member 4. The door comprises a flexible curtain 5 reinforced by 35 stiffening bars 6. The curtain can be rolled up in conventional manner on a wind-up shaft (not shown in the figure) received in the top cross-member 4. The wind-up 5 shaft is driven by an electric motor 8 via a transmission 9, in association with various electrical control members, such as an end-of-stroke switch 10. The uprights can support the top cross-member 4, or 5 else it can be fixed via a bracket to the wall, above the opening of the doorway. In the embodiment shown in Figures 1 to 3, each upright has an essentially vertical rigid element that is advantageously a flat member 15 (made of iron) and a 10 slideway 16 constituted by a channel section member or folded metal sheet (cf. Figure 2, where the flat 15 and the slideway 16 are shown as being slightly apart from each other so as to show up more clearly the connection means between these two elements; also for simplification 15 purposes, no lock-nuts are shown). In this example, each slideway is mounted so as to be capable of moving just a little, and it is movable against resilient means, starting from a rest position. It is in this rest position that the door operates 20 normally. Means are provided to trigger a signal when the slideway moves away from its rest position. The flat iron and the slideway are independent. Each of them is fixed to the ground in appropriate manner, and the flat iron is fixed to the wall, at the edge of the doorway 25 opening, by any appropriate means. The ground fixing of the slideway enables the top portion thereof to move a little, while remaining pressed against the flat iron, or said slideway is sufficiently flexible to allow its top end to be displaced a little. 30 To hold the slideway 16 in a suitable rest position, a fastening is provided as described below by way of example. A hole 21 is provided through the web of the slideway, or possibly through a tongue 22 extending the web beyond the flanges. A hole 23 is provided through 35 the flat iron 15; the flat iron and the slideway are united by a pin or a loose bolt. The hole 23 through the flat iron is elongate, and as a result the slideway can 6 move relative to the flat iron by sliding against it. The length of such displacement is set by the horizontal size of the hole 23, and it may be of the order of a few centimeters, depending on the size of the door. 5 In Figure 3, the upright 2 of the door is shown in profile. The flat iron 15 has a rectilinear vertical edge on the left since it is pressed against the wall, while its right edge is enlarged for matching the top cross-member 4. The edge must correspond to the front 10 face of the door, as shown in Figure 1. The end of the bolt 24 is fixed to a shoe 27 capable of sliding between two guides 28 and 29 secured to the wall of the flat iron 15. The shoe can thus move at the same time as the top portion of the slideway 16 moves. 15 The shoe 27 is urged to the right by a spring 31 suitably fixed to the right-hand end of the shoe and to a point 32 on the flat iron. In front of the left-hand end of the shoe, there is disposed a relay 35 which is actuated by a lever 36 hinged at one end to the relay and 20 having its other end bearing resiliently against the left-hand end of the shoe 27. Figure 4 is a perspective view of a fixing piece 40 for the shoe 27. This piece comprises a soleplate 41 having two ribs 28 and 29. The soleplate is suitably 25 fixed to the flat iron 15 of the upright 2. Advantageously, an identical device is placed symmetrically on the other upright 3. In the rest state, i.e. when the bolt 24 is held pressed towards the front end 23A of the hole 23, the 30 door operates normally. The ends of the bars 6 and the edges of the curtain 5 slide freely in the slideways 16. If pressure is exerted against the front face of the curtain, at any point thereof, while the curtain is down or while it is moving, then said force is transmitted to 35 the bars 6. The thrust is transmitted via at least one of the bars to at least one of the slideways.
7 The slideway moves because of the clearance provided by the elongate hole 23 in the corresponding upright. The shoe 27 moves the lever 36 and the relay 35 is actuated. It causes a signal to be issued, which signal 5 can control any desired function, and in particular it can cause the door to be raised. The same result can be obtained if action is taken directly on the slideway instead of acting on the curtain. In any event, triggering sensitivity can be 10 adjusted by selecting the spring 31. Figure 5 shows a variant of the apparatus shown in Figure 2. In this variant, the flat iron does not extend all the way down. In practice, the element 15A can be constituted by a 15 downwards extension from the end sheet constituting the top cross-member 4. Under such circumstances, the lateral upright is constituted solely by the slideway 16 which does not participate in the function of supporting the cross-member 4, which cross-member is fixed to the 20 wall over the doorway, like a bracket. In the examples described above, the signal can be triggered by applying a force to one side only. Where desirable, the device can be designed to operate from both faces of the curtain. It suffices for the hole 23 25 in the flat iron of the upright to be long enough to receive two springs, each pulling from its own side. The bolt 24 will then remain in the equilibrium position of the two springs and two relays can be provided or a double-acting relay can be provided. 30 It may be observed in passing that each slideway can be fixed to the ground in releasable manner. Once the fixing has been released, the slideway can be tilted to one side or the other of the door by oscillating about the bolt 24. Naturally, this property is associated with 35 the example described since the person skilled in the art will understood that any movement or deformation of a slideway can be monitored by an appropriate detector, 8 providing the slideway is capable of performing some movement or of being subjected to some deformation.