ES2877652T3 - Sliding door, in particular elevator sliding door - Google Patents

Abstract

Sliding door, in particular elevator sliding door, with a door frame and at least one first door element (3), which can be displaced relative to a second door element (5) to form a common overlap (O), a drive unit (7) to move the first door element (3), a safety unit (15) to interrupt a possible displacement movement of the first door element (3) when an object (24) penetrates into an area security (13) extending on an edge (9) of the overlap (O) running transversely to the direction of movement of the first door element (3) along this edge (9), and a control device (25) for controlling the drive unit (7) and the safety unit (15), the safety unit having a radiation source (19) and a radiation sensor (21) for monitoring the safety zone (13) by radiation from the radiation source (19), and the control equipment being designed ol (25) to cause the actuation equipment (7) to interrupt any displacement movement of the first door element (3) if the security equipment (15) signals the presence of an object (24) in the security zone ( 13), the radiation source (19) and the radiation sensor (21) being arranged at one end of the security zone (13) and being configured together as a reflected radiation sensor (15) that responds to radiation from the radiation source (19) that is reflected from any object (24) in the safety zone (13) towards the radiation sensor (21), the reflected radiation sensor (15) being arranged and configured in such a way that it does not respond to the radiation of its radiation source (19) passing unhindered through the safety zone (13), the radiation source (19) emitting the radiation as a beam directed vertically downwards, being the installation site of the radiation source (19) and the radiation sensor (21) u n upper end of the door, characterized in that the control equipment (25) is designed to cause the electric drive equipment (7) to exert an active force on the first door element (3) that is directed in opposition to the force that has caused the displacement of the first door element (3) in the determined direction of movement, when, upon said displacement of the first door element (3) in the determined direction of movement, the security equipment (15) signals the presence of an object (24) in the security zone, because the electrical drive equipment (7) can be excited by controlled supply of electrical energy to alternately generate a force that moves the first door element (3) in the direction of movement or a force directed in the opposite direction, the control equipment (25) being designed to supply at least one pulse of electrical energy to the drive equipment electrical switch (7) to excite it so that it generates the force directed in the opposite direction when, in the event of a displacement of the first door element (3) in the determined direction of movement, the security equipment signals the presence of an object (24 ) in the safety zone (13), and because the control equipment (25) is designed to establish the duration of the electrical energy pulse to generate the force directed in the opposite direction depending on the current displacement position and/and /or the current movement speed of the first door element (3) during its movement in the determined direction of movement.

Description

DESCRIPTION

Sliding door, in particular elevator sliding door

The invention relates to a sliding door, in particular a sliding elevator door.

Sliding doors of the types mentioned are usually provided and function as self-opening and closing doors. They are often used as elevator doors, either as car or elevator shaft doors. These types of sliding doors are often also found in the entrance areas of office buildings, department stores and other public buildings.

Since in the operation of automatic sliding doors the mobile door elements move relative to each other by means of a motor, it is necessary to take special precautions to avoid accidents and damage to people and objects in the area. movement of these door elements.

Door leaves can in particular be considered as movable elements, whereby the following considerations, when speaking of movable door elements, mainly refer to door leaves. The emergency stop procedure in case objects enter the security zone is relevant in particular in relation to the door opening operation.

In particular, door leaves that are made of glass panes or have glass pane fillings appear to be preferred objects for hand contact. Children, in particular, seem to have a tendency to touch the glass surfaces of these sheets with their fingers. In case the fingers come into contact with a door leaf moving in the door opening direction, it may happen that the fingers in question are dragged by the door leaf in the door opening direction until they are caught in the gap between the moving door leaf and, for example, a pillar of the door frame or, in the case of a telescopic door, for example, in the gap between the telescopic door leaves that move in the direction opening, forming an overlap, and are thus crushed. Said gap runs along a respective vertical edge of the common overlap between the door leaf and the frame or between two door leaves. The problem of fingers or, more generally, of objects entering the gap between the door leaf and the frame or between two leaves of a sliding door has already been addressed by several door manufacturers, and different have been proposed solutions to prevent fingers or, more generally, objects from entering said gap.

For example, a generic telescopic sliding door with at least one pair of door elements movable relative to each other, namely a door frame and one or more door leaves, is known from DE 19937561 A1, the door elements moving relatively between them to open the door and delimiting between them a free gap, that is, a gap of the type explained above, in the common overlapping area. The well-known telescopic sliding door has a security equipment with a surveillance equipment that monitors the presence and / or the penetration of an object in a security zone that extends on the vertical edge of the common overlap that runs transversely to the direction of movement. of the door elements along this edge. Under the control of a control team, the security team completes the opening movement of the telescopic sliding door by stopping the electric drive of the door when the surveillance team signals a penetration or the presence of an object in the security zone by means of the corresponding fault warning signal. In particular in the case of door leaves with a relatively large mass, it can happen in the case of these known telescopic sliding doors that the moving door leaves do not stop immediately due to their inertia when an object enters the safety zone , but continue to operate slightly after the respective door operator has received the emergency stop instruction and has been switched off. This means that there is a residual risk that an object will enter the free gap, even if the safety equipment has immediately reacted to the corresponding fault warning signal from the control equipment.

The security equipment of the telescopic sliding door known from the document DE 19937561 A1 comprises as monitoring equipment an essentially mechanically operable impact bar comprising a strip arranged movably or deformably on the door element, or else a strip sensor operating predominantly electronically or optoelectronically and having at least one unidirectional and / or bidirectional light barrier. The monitoring device is arranged next to or in the free gap at the edge of the overlap zone between the door elements that move relative to each other, that is, in the example case, in and along one edge of the End face of a door element in the surveillance zone and, in particular, preferably in the door element that has not traveled any path of movement or a smaller one during the opening. Basically, the principle is used in this connection that a fault warning signal is activated when the impact bar is deformed or displaced due to an object acting on it. Said deformation or displacement of the impact strip is detected optoelectronically in some embodiments of document DE 199 37 561 A1 by means of light barriers that are aligned in the direction of movement of the door elements and respond if the beam or beams The light sources of the emitter do not reach the receiver or receivers of the light barriers in question in a predetermined way, which occurs, for example, in the case of a deformation or displacement of the mechanically actuated impact strip if an object is fits into the gap in the security zone. Such safety equipment is not only relatively expensive and difficult to install, but it is also comparatively slow in its response behavior, so there is a risk that an object may penetrate the free gap before the system can stop the door from moving.

Other door systems with safety equipment to prevent the penetration of objects into the free gap of the overlap area between two moving door elements relative to each other, forming the overlap zone, specifically between a moving door leaf and another element Door panels, either a door leaf or a door frame section, are known, for example, from EP 2074270 B1 and DE 102004 053 820 B4. These other known door systems also have, as control devices, safety bands or switching arrangements that are mechanically actuated and that respond to their displacement or deformation caused by objects that have entered the free gap to activate a warning signal of failure, such that the safety equipment then stops the door drive under the control of a corresponding control equipment. In these known door systems, the security equipment is relatively complex in design and has a comparatively slow response behavior. Other examples of sliding doors are known from EP 1243544 A2 and WO 01/96226 A1. Furthermore, reference is made to EP 2332876 A1 and E 10260 109 A1.

The aim of the present invention is to overcome such disadvantages of known automatic sliding doors and to indicate possibilities to improve the detection of the presence and / or penetration of an object in the gap of the overlapping zone of two door elements of the doors Automatic slides that move relative to each other forming the overlap zone and that are positioned transversely to the direction of movement consecutively and at a small distance from each other, in order for the safety equipment to present a fast response behavior, operate reliably and, in particular, are easy and safe to install. Preferably, the surveillance equipment of the security teams should also be compact in design and not prone to damage.

For this, a sliding door is proposed according to claim 1.

Reflected radiation sensors of this type are also available on the specialist market with a very compact construction and at an economical price as reflector light sensors. They are easy to install, take up little space and are reliable in operation. In reflected radiation sensors, radiation is reflected off the object to be detected. Radiation transmitters and receivers are usually housed in parallel with each other in a common housing. Reflected radiation sensors are also available in a design as so-called background suppression reflected reflection sensors. These work particularly reliably when it comes to detecting dark objects against a light background. Reflected radiation sensors, which are suitable for distance determination, are sometimes also referred to as reflection distance sensors or optical distance sensors. There are two basic principles of operation for reflected radiation sensors.

A first operating principle is the triangulation principle, according to which the sensor can switch or emit a fault warning signal when the radiation emitted by the radiation emitter is reflected at certain angles and consequently hits certain areas of the radiation receiver of the reflected radiation sensor.

The second principle of operation is the transit time detection principle, according to which the sensor can switch or emit a fault warning signal if the radiation pulses emitted by the radiation transmitter are reflected back to the radiation receiver of the radiation sensor reflected within a certain time window, metrologically detecting the transit time of the radiation pulses.

For the purposes of the present invention, all the mentioned reflected radiation sensors are suitable. However, reflectance light sensors, in particular infrared light radiation sensors, preferably come into consideration. The light sources of these reflected light sensors are, in particular, light-emitting diodes and, preferably, IR laser diodes. Combined light sources that can emit, for example, visible light and infrared light along the same optical path, also come into consideration, with the visible light facilitating the adjustment of the sensor system or surveillance equipment due to the visible light point. and infrared light serving as true reflection light sensor measurement light. Light sensors that come into consideration for detecting reflected light are, for example, photodiodes, phototransistors or, if necessary, photoresistors. Unlike conventional reflective light barriers, which feature a light transmitter and a light receiver on one side of the surveillance path and a light reflector on the opposite side of the surveillance path, and which respond to a interruption of the light beam on its path from the light transmitter to the light reflector and from the light reflector to the light receiver, the reflective light barrier used according to the invention responds to light that is reflected by the object to be detected in the surveillance zone itself. Light barriers, whether they are single path light barriers or reflective light barriers, come less into consideration for the invention, since they involve more assembly work and their reliable and reproducible operation depends on whether the light receiver or reflector its light entry window is clean or dirty. The problem of contamination in the case of light barriers is certainly relevant for the considerations made in the present document, since according to the concept of the invention, in addition, the security zone to be monitored normally extends from vertical form from the upper end to the lower end of the door in question and a light barrier element (transmitter, reflector or receiver) should be provided at the threshold of the door. However, this is a place prone to soiling, as people walking through the door can just walk in with shoes on. According to the invention, this problem is overcome with reflected radiation sensors, since, according to the invention, the upper end of the door is chosen as the installation site. Thus, there is no need to install system components on the floor or on the door sill.

Within the framework of the invention, systems which operate with acoustic radiation, in particular with ultrasonic radiation, and which consequently react to the sound reflected by the object to be detected in the monitored area, could also be used as reflected radiation sensors. Apart from the special type of radiation, these acoustic reflection sensors can work in the same way as reflection light sensors.

The invention can be used with telescopic sliding doors and with non-telescopic sliding doors. In the case of telescopic sliding doors, the door opening operation involves the joint lateral movement of at least two door leaves in a common door opening direction, the door leaves being located parallel to each other and arranged in a consecutively transversely to the door opening movement direction. One of the door leaves moves faster than the other door leaf, such that during the door opening operation there is an increasing area of overlap between the two door leaves. In this overlapping area, the two door leaves define a gap between them, sometimes called a free gap. Similarly, a gap is also formed in which a respective door leaf overlaps with a consecutively positioned door frame or door jamb section during the door opening movement. This last situation usually occurs both in telescopic sliding doors and in non-telescopic sliding doors. As already mentioned, the risk of a person's fingers being dragged by a moving door leaf into the gap in question and crushed in the gap area will be counteracted. In general, the risk of small objects accidentally entering the gap and causing damage to the objects and / or the sliding door will be counteracted.

To this end, according to the present invention, a security zone is monitored which extends at one edge of the overlap zone which runs transversely to the direction of movement of the moving door leaf, along this edge. In the case of horizontally moving door leaves, this edge usually runs vertically. Consequently, the security zone normally runs vertically. Depending on the mode of operation of the reflected radiation sensor, the safety zone can extend over a region of the vertical length of the door leaf in question or the entire vertical length of the door leaf. A reflected radiation sensor will be suitably arranged at the upper end of the door leaf that moves more slowly in the direction of the opening movement (in the case of the telescopic sliding door) and / or at the top near the section frame behind which the door leaf moves during the door opening movement. With this mounting position, the reflected radiation sensor is protected from being stepped on by the users of the sliding door with their shoes and, in this respect, from getting dirty. Depending on the arrangement and orientation of the reflected radiation sensor, the safety zone may be set more or less within the gap or outside, near the entrance to the gap. If a finger or any other object enters said safety zone during a door opening operation, it reflects the radiation from the transmitter of the reflected radiation sensor towards the radiation receiver of the reflected radiation sensor, when this reflected radiation is detected , the security equipment signals the presence of an object in the security zone, whereby the control equipment causes the drive equipment to interrupt a new movement of displacement of the moving door leaf.

Since object detection can take place before entering the gap and, in particular, without contact, if the security zone is configured appropriately, a very rapid reaction of the security team is possible when an object enters the gap. the safety zone, so that the object can be prevented from even entering the gap at the edge of the overlap zone. It is also not necessary for the object to come into contact with the door leaf or frame section in question before the security team responds. As soon as it enters the beam path of the reflected radiation sensor, an object can be detected even before it comes into contact with the sliding door. This also serves to speed up the response of the security system. The sliding door according to the invention is therefore characterized in a particular way in that its security system reacts very quickly and reliably, it can be realized with simple means and it can be installed in a reduced space and with little effort.

A main area of application of the invention is that of automatic sliding elevator doors, in particular telescopic sliding doors, although the invention is not restricted thereto.

The movable door leaves of an automatic sliding door can have a relatively large mass and therefore also a relatively large mass inertia, which can have a disadvantageous effect during the emergency stop operation, that is, the operation of interruption of the movement of a corresponding door leaf when an object enters the security zone. Thus, it has been observed in some state-of-the-art automatic sliding doors that the door leaves did not immediately go to the mechanical stop state when the electrical drive energy was removed, but continued to move. slightly due to the inertia of its mass. This excessive displacement of the door leaf in question could be sufficient for any object to enter the free gap of the overlap zone between the door leaf and the other door element in question, causing crushing in this regard. This effect is also the result of an insufficiently fast response or reaction of the sliding door security system.

Furthermore, according to the invention, the control equipment is designed to make the electrical drive equipment exert an active force on the door element which is directed in opposition to the force that has caused the door element to move in the direction of determined movement, when, upon said movement of the first door element in the determined direction of movement, the security equipment signals the presence of an object in the security zone. The direction of movement determined is normally the opening direction of the door.

In general, this can also refer to telescopic sliding doors and non-telescopic sliding doors. Also in this case, a door leaf comes into consideration as the first door element. The second door element is predominantly another movable door element (in the case of a telescopic sliding door) or a door frame section or a frame post in the manner already explained above.

The basic idea is to generate a force opposed to an inertial movement of the door leaf in question immediately after detecting the presence or penetration of an object in the security zone and to exert this force on the door leaf for a short period time, thus causing the door leaf to stop as immediately as possible or even move back slightly.

The counter force is normally generated by suitably driving an electric motor driving the control equipment with a pulse of electrical energy ("thrust reversal pulse") to cause a reversal of the drive or override of the continuation of coasting of the drive system.

Thus, according to a variant of the invention, the maximum electrical drive energy available in the drive system can be supplied to the motor during the thrust reversal pulse.

Preferably, the electrical energy pulse has a duration in the range of 10 ms -500 ms, preferably in the range of 50 ms-250 ms.

According to the invention, the control equipment is capable of determining the duration of the electrical energy pulse to generate the force directed in the opposite direction from the current displacement position and / or the current displacement speed of the first door element. when moving in the determined direction of motion.

Preferably, the first door element is a door leaf and the second door element is a door frame section or other door leaf of a telescopic sliding door.

Preferably, at least the first door element comprises or is formed by a glass pane.

The sliding door can be, for example, an elevator door, in particular a telescopic sliding door of an elevator car or of an elevator shaft.

An exemplary embodiment of the invention will be explained in more detail below with reference to the drawings.

Figure 1a shows in a highly simplified representation a front view of an automatic sliding door in the closed state, in which an upper area of the door frame is shown partially fragmented to illustrate the drive equipment.

Figure 1b shows a sectional view of the sliding door of figure 1a corresponding to the section plane b-b of figure 1a.

Figure 2a shows the sliding door of Figure 1a and Figure 1b in an almost completely open state in a front view corresponding to Figure 1a.

Figure 2b shows a sectional view of the sliding door of figure 2a corresponding to the section plane b-b of figure 2a.

Figure 3a shows the sliding door in a snapshot during the door opening operation in a front view corresponding to figure 1a and figure 2a, a person entering the security zone.

Figure 3b shows a sectional view of the sliding door of figure 3a with the cut plane bb of figure 3a.

The automatic sliding door shown in the figures is a telescopic sliding door with a frame 2 and two door leaves 3, 5, which move in parallel and horizontal alignment with each other in two successive parallel planes of movement E3, E5 during the opening operation and the closing operation of the telescopic sliding door. The door leaves 3, 5 can be made of glass panes, for example, and can be transparent. A drive unit 7 serves to open or close the telescopic sliding door depending on the case, whereby the door leaf 3, located on the right in Figure 1a and, according to Figures 1a and 1b, positioned in the plane of displacement E3 somewhat further back, it moves faster than the door leaf 5, located in the displacement plane E5 somewhat further forward. In telescopic sliding doors of this type, the door leaf that goes behind in the direction of the opening movement and that goes in front in the direction of the closing movement (in the example, door leaf 3) usually moves at a speed approximately twice that of the other door leaf.

The two door leaves 3, 5 have a slight distance A from one another orthogonal to the displacement planes E3, E5, such that they can move without reciprocal contact along the displacement planes E3, E5 to the closed position according to figure 1a and to the open position according to figure 2a. Due to the different speeds of movement of the door leaves 3, 5, during the opening operation of the telescopic sliding door, an increasing overlap O occurs (that is, an increasing mutual overlap - seen in the direction orthogonal to the displacement planes E3, E5 - of the two door leaves 3, 5) with a vertical edge that coincides with the vertical edge 9 of the slowest moving door leaf 5 and located behind in the direction of the opening movement . In this regard, the two door leaves 3, 5 delimit a narrow vertical gap 11 which runs along the edge 9.

Due to the different speeds of movement of the two door leaves 3, 5, in this type of telescopic sliding door there is a risk that the faster moving door leaf 3 may move objects that are leaning against it laterally. towards the gap 11 during the opening operation. This is particularly critical if the fingers of a person, in particular the small fingers of a child, enter the gap 11 and are crushed in this regard. In the past it has often been shown that young children like to touch the surface of glass panes, and specifically also glass door leaves of telescopic doors. In this regard, the situation described above can easily be reached.

The present invention addresses this problem and offers a particularly advantageous possibility to prevent objects from entering the gap between the door leaves 3, 5.

For this, the invention offers a reliable and simple possibility to monitor a security zone 13 that extends near the entrance of the gap along the edge 9 of the overlap O of the two door leaves 3, 5 and to stop or interrupt immediately the opening movement of the two door leaves when an object is present in or enters the security zone 13.

For this, a safety device is provided that has a reflective light sensor 15 which, in the case of the example, is fixed at the upper end of the slower-moving door leaf 5 and is oriented in such a way that it emits a light beam 17 vertically downwards with its radiation emitter 19. This light beam 17 defines the safety zone 13 to be monitored. The reflective light sensor 15 also has a radiation receiver 21 or radiation sensor. The reflective light sensor 15 operates in such a way that it reacts to light from its radiation emitter 19 which is reflected by an object in the safety zone 13 towards the radiation receivers 21, but not to light from its radiation emitter. radiation 19 passing through safety zone 13 unobstructed from top to bottom.

In Figures 3a and 3b, a situation is indicated in which a person 23 introduces a hand 25 into the security zone 13. In doing so, the person 23 interrupts the beam of light 17 directed downwards with the hand 24 and produces due to the hand 24 a return reflection (usually diffuse) of the light from this light beam 17 towards the reflection light sensor 15. The light receiver 21 of the reflection light sensor 15 registers said retroreflected light, which is interpreted as the presence of an object in the security zone 13. The reflection light sensor 15 is in data transmission communication with a control device 25 of the telescopic sliding door. The control equipment 25 receives a failure warning signal from the reflection light sensor 15 when the presence of an object in the security zone 13 is detected in the manner explained above.

The control equipment 25 also serves to control the door drive equipment 7, that is, it generates control and switching commands for an electric motor 27 in order to supply it with electric drive power in a controlled manner and to specify the respective direction of operation. motor turn. Depending on the direction of rotation of the electric motor 27, the door leaves 3, 5 move in the direction of the opening movement or in the direction of the closing movement. The door drive equipment 7 shown in a very simplified way in the figures is a cable drive, in which the electric motor 27 drives a deflection roller 31 to the right above the door opening 4 by means of a drive belt 29 or the like, the diverter roller 31 having two cylindrical diverter roller sections 33, 35 arranged against each other concentrically with respect to the axis of the diverter roller, of which the diverter roller section 33 has a diameter greater than the deflection roll section 35. Each of the two deflection roll sections 33, 35 is surrounded by a respective endless traction wire 37, 39 and serves for actuation and deflection. A second deflection roller 41 is rotatably arranged to the left, above the door opening 4, and also has two cylindrical deflection roller sections 43, 45 of correspondingly different diameters, which are arranged concentrically to its deflection roller axis, a against the other, and are surrounded by endless traction cables 37, 39 and serve to deflect them. The faster-moving door leaf 3 is connected to the lower leg 36 of the endless traction cable 37 which rotates around the larger diameter deflection roll sections 33, 43 by a drive member 47, while the Another door leaf 5 is connected to the lower leg 38 of the endless traction cable 39 which rotates around the deflection roller sections 35, 45 by means of a drive element 49. When the electric motor 27 is controlled in such a way that drives the deflection roller 31 to rotate clockwise (with reference to figure 1a), the drive elements 47, 49 move to the left in figure 1a with the lower branches 36, 38, such that the door leaves 3, 5 also move to the left in the direction of the door opening movement. If the electric motor 27 is controlled in such a way that it drives the deflection roller 31 to rotate counterclockwise (referred to in Figure 2a), the door leaves 3, 5 move from their home position. opening according to figure 2a in the direction of closing movement to the right with the lower branches 36, 38.

Since the pull wire 37 rotates around the deflection roll sections 33, 43 with the larger diameters, it has a higher speed of revolution than the other pull wire 39 which rotates around the deflection roll sections 35, 45 with the smallest diameters. Consequently, the door leaf 3 moved by the pull wire 37 also moves faster in the direction of closing movement of the door and in the direction of opening movement of the door than the door leaf 5 moved by the pull wire 39. Depending on whether the control equipment 25 controls the electric motor 27 to rotate clockwise or counterclockwise, the door leaves 3, 5 move in the same direction. door closing movement direction or door opening movement direction.

At this point it should be clearly emphasized that the traction cable drive equipment 7 explained above has been presented only by way of example as a suitable drive equipment for a sliding door according to the invention. Other drive devices, such as spindle drives, linear motor drives, etc., also come into consideration as door drives.

Essential is only that the relevant drive motor of the drive equipment responds quickly to direction reversal control instructions from the corresponding control equipment, for reasons which will be explained below.

If, in the case illustrated in Figures 3a and 3b, the security equipment detects the presence of an object 25 in the security zone 13, the control equipment 25 reacts immediately by sending a direction reversal control instruction to the electric motor 27, in such a way that the electric motor 27 is not only deprived of the electric drive energy for the actual movement of the door leaves 3, 5 in the direction of the door opening movement, but the electric motor 27 it also receives a brief pulse of electrical drive energy to reverse the direction of motion ("thrust reversal pulse"). In this way, after the removal of the electrical drive energy in question, the inertial movement of the door leaves 3, 5 in the direction of door opening movement in response to a fault warning signal is actively counteracted. of the reflection light sensor 15. In this way, once an object 25 has been detected in the safety zone 13, the movement of the door leaves 3, 5 in the direction of movement of the door leaves 3, 5 is stopped as quickly as possible. door opening. The duration of said "thrust reversal pulse" can be selected, if necessary, as a function of the mass or the inertia of the mass of the door leaves 3, 5.

It should also be noted that in the frame 2, in the upper left part of the door opening 4, a second security zone 13 'is configured, defining and monitoring a corresponding reflection radiation sensor 15' this second security zone 13 '' to detect the approach of an object to the overlapping gap 6 between the frame section 8 that delimits the door opening 4 on the left and the second door leaf 5 and, in case of detection of an object in the second area of security 13 ', in this case causing the control equipment to activate the emergency stop of at least the second door leaf 5 in the manner described with respect to the detection of an object in the security zone 13.

Claims (12)

1. Sliding door, in particular elevator sliding door, with a door frame and at least one first door element (3), which can be moved with respect to a second door element (5) forming a common overlap (O ), a drive unit (7) to move the first door element (3), a safety equipment (15) to interrupt a possible movement of the first door element (3) when an object (24) penetrates into a security zone (13) that extends on an edge (9) of the overlap (O) that runs transversely to the direction of movement of the first door element (3) along this edge (9), and a device control panel (25) to control the drive equipment (7) and the safety equipment (15), the safety equipment presenting a radiation source (19) and a radiation sensor (21) to monitor the safety zone ( 13) by means of radiation from the radiation source (19), and the equipment being designed to ntrol (25) to make the drive equipment (7) interrupt any movement movement of the first door element (3) if the security equipment (15) signals the presence of an object (24) in the security zone ( 13), the radiation source (19) and the radiation sensor (21) being arranged at one end of the safety zone (13) and being configured together as a reflected radiation sensor (15) that responds to radiation from the radiation source (19) that is reflected from any object (24) in the safety zone (13) towards the radiation sensor (21), the reflected radiation sensor (15) being arranged and configured in such a way that it does not respond radiation from its radiation source (19) that passes unhindered through the safety zone (13), the radiation source (19) emitting radiation as a beam directed vertically downwards, being the installation site of radiation source (19) and radiation sensor (21 ) an upper end of the door, characterized in that the control equipment (25) is designed to make the electric drive equipment (7) exert an active force on the first door element (3) which is directed in opposition to the force that has caused the displacement of the first door element (3) in the determined direction of movement, when, upon said movement of the first door element (3) in the determined direction of movement, the security equipment (15) signals the presence of an object (24 ) in the security zone, because the electrical drive equipment (7) can be excited by controlled supply of electrical energy to alternately generate a force that moves the first door element (3) in the determined direction of movement or a force directed in the opposite direction, being conceived the control equipment (25) to supply at least one pulse of electrical energy to the electrical drive equipment (7) to excite it to generate the force directed in the opposite direction when, in case of a displacement of the first door element (3) In the determined direction of movement, the security equipment signals the presence of an object (24) in the security zone (13), and because the control equipment (25) is designed to establish the duration of the electrical energy pulse to generate the force directed in the opposite direction as a function of the current displacement position and / or the current displacement speed of the first element of door (3) during its movement in the determined direction of movement. Sliding door according to claim 1, characterized in that the reflected radiation sensor (15) is designed as a reflective light sensor. Sliding door according to claim 2, characterized in that the radiation source (19) comprises at least one light-emitting diode, preferably an infrared LED and / or a laser diode, and in that the radiation sensor (21) comprises at least one photodiode and / or at least one phototransistor. Sliding door according to claim 1, characterized in that the reflected radiation sensor is designed as an ultrasonic reflection sensor. Sliding door according to one of the preceding claims, characterized in that the reflected radiation sensor (15) operates according to a triangulation principle and / or according to a radiation time measurement principle. Sliding door according to one of the preceding claims, characterized in that the first door element is a door leaf and in that the second door element is a door frame section or another door leaf. Sliding door according to claim 6, the reflected radiation sensor being arranged in the door frame. Sliding door according to one of the preceding claims 1-5, characterized in that it is a telescopic sliding door and in that the first door element (3) and the second door element (5) are telescopically movable door leaves of the telescopic sliding door, the first door element (3) being able to move faster than the second door element (5) forming the common overlap (O) and the reflected radiation sensor (15) being arranged in the second door element ( 5). Sliding door according to one of the preceding claims, characterized in that the movement movement of the first door element (3) relative to the second door element (5) runs in the horizontal direction and in that the reflected radiation sensor (15 ) is arranged at the upper end of the second door element (5), in such a way that the security team (15) can monitor the security zone (13) from above. Sliding door according to one of the preceding claims, characterized in that the electrical energy pulse has a duration which is in the range of 10 ms - 500 ms, preferably in a range of 50 ms - 250 ms. Sliding door according to one of the preceding claims, characterized in that at least the first door element (3) comprises or is formed by a glass pane. Sliding door according to one of the preceding claims, characterized in that it is a telescopic sliding door of an elevator car or of an elevator shaft.