EP3255010A1

EP3255010A1 - A safety system for sliding elevator doors, an elevator and a method

Info

Publication number: EP3255010A1
Application number: EP16173912.3A
Authority: EP
Inventors: Simo Sairanen
Original assignee: Kone Corp
Current assignee: Kone Corp
Priority date: 2016-06-10
Filing date: 2016-06-10
Publication date: 2017-12-13

Abstract

A safety system for sliding elevator doors (1) is disclosed. The system comprises a sliding door panel (2) and a door frame (3), or two sliding door panels (2) moveable in the same direction with different speeds. The system is characterized in further comprises a force-sensing resistor (4) extending along a side (5) of the door frame (3) facing the door panel (2), or along a side (6) of the slower-moving door panel (2b) facing the faster-moving door panel (2a), for detecting an object between the door panel (2) and the door frame. The system is further characterized in that movement of the door panel (2) is configured to be stopped when a characteristic, such as force, or speed of change in the force exerted on the force-sensing resistor, exceeding a predetermined threshold value is detected by the force-sensing resistor (4). Also an elevator, a door frame, a door panel and a method of installing said system are disclosed.

Description

TECHNICAL FIELD

The present disclosure relates to a system for detecting finger trapping in a sliding elevator door. The present disclosure further relates to a door frame, to a door panel, and to a method of installing a system according to the present disclosure.

BACKGROUND ART

When sliding elevator doors open, each door panel is retracted past a vertical door frame. If there are more than two door panels, the door panels furthest away from the door frame slide past the door panel closer to the door frame.
Especially in elevators with glass doors, the mechanism can cause extensive damage to body parts, especially to fingers, if the body parts are pulled with the moving door panel inside the frame, or between the two door panels moving in the same direction. The problem is most pronounced with small children, who have small hands and fingers, and who are curious to look into the elevator shaft. While leaning against the door panel with both hands, they might not notice that the door opens, or they may react too slowly to the movement, and have their fingers pulled between the door frame and the moving door panel.
A great deal of effort has been invested in creating a mechanism that would reduce the damage inflicted on hands getting between the door panel and the door frame.
For example, in document KR 101442577 , a safety device for hand protection using a tilting function is disclosed. Therein, the device performs a tilting process for reversing a tilting plate which is a part of one edge of an elevator frame when the hand of a user is caught between an elevator frame and an elevator door. A gap opens between the elevator frame and the elevator door by reversing an outer plate which can be tilted on the surface of the door, thereby allowing safely and simply taking the hand out of the gap.
In document EP 1770046 , a safety device is disclosed, wherein the elevator doors include an electro-sensitive strip, comprising a middle edge orthogonally developed from the base, vertically extends on at least one of the jambs and/or doors and/or electrically connected to a door opening control device or to the lift system control board.
In document JP 2005008300 , an optical system is employed, and in document EP 1474582 , a capacitive sensor fastened to a door panel, or positioned in correspondence with an external frame or jamb is disclosed.
Further, in document EP 1289870 , a safety mechanism comprising a detector device provided at least at each sliding door, in the area of a pinching edge between a sliding door and a door jamb, and/or between two adjoining sliding door panels. Depending on the detected state of the monitored areas, the detector device generates a door release signal, or provides the interruption of the drive mechanism for opening the sliding door.
The currently available solutions fail to provide a robust, low-cost, but at the same time sensitive mechanism for improving sliding door safety. The inventors have therefore recognized the need for a new solution for automatic sliding door safety.

SUMMARY

An object of the present disclosure is to alleviate the problems associated with prior-art solutions. It is especially the object of the current disclosure to provide a reliable and sensitive method for detecting the entrapment of hands between a moving door panel and a door frame, or between two door panels moving in the same direction.
The current system, door frame and method are in particular, but not only, intended for elevators, especially for passenger or cargo elevators of buildings.
An aspect of the safety system for sliding elevator doors according to the present disclosure is characterized by what is presented in claim 1.
Another aspect of the safety system for sliding elevator doors according to the present disclosure is characterized by what is presented in claim 2.
An elevator comprising a system according to the present disclosure is characterized by what is presented in claim 12.
A door frame according to the present disclosure is characterized by what is presented in claim 13.
A door panel according to the present disclosure is characterized by what is presented in claim 14.
The method for installing the safety system according to the present disclosure is characterized by what is presented in claim 15.
The safety system according to the present disclosure and the method for installing it can offer at least one of the following advantages over prior art.
The system is concealed behind the elements of the elevator door, making the system inconspicuous. Further, the system only senses objects that are about to be trapped, and not objects that are otherwise in the vicinity of the moving door panel. These properties help avoid accidental or deliberate triggering of the system.
The force-sensing resistor is simple to install and to connect to the elevator door controller. The installation is fast and the need for custom-made components can be avoided. Thus, it is economically feasible to employ the system in both new and existing elevators.
Force-sensing resistors are reliable in operation also over extended periods of time. Further, it is possible to adjust the force needed to stop the door movement. Thus, false alarms can be reduced compared to systems that can only detect the presence or absence of a signal. On the other hand, the system is sensitive enough to sense even a small force compared to the forces necessary to move the elevator door panels.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the disclosure and constitute a part of this specification, illustrate embodiments and together with the description help to explain the principles of the invention but the invention is not limited to the specific embodiments illustrated in the drawings. In the drawings:

Fig. 1 presents a centrally opening sliding elevator door comprising the system according to the present disclosure viewed from the direction of the elevator landing.
Fig. 2A presents a cross section of the elevator door in fig. 1 along the line A-A'.
Fig. 2B presents a four-paneled centrally opening sliding elevator door similarly to fig. 2A.
Fig. 2C presents a three-paneled side-opening sliding elevator door similarly to figs 2A and 2B.
Fig. 3 presents a close-up view of the area A" in fig. 2A and demonstrates the operating principle of the system according to the present disclosure.
Fig. 4, panels A to F, depicts embodiments of the door frame comprising a force-sensing resistor.

DETAILED DESCRIPTION

In one aspect, a safety system for sliding elevator doors is disclosed. The system comprises a sliding door panel and a door frame and is characterized in that the system further comprises a force-sensing resistor extending along a side of the door frame facing the door panel for detecting an object between the door panel and the door frame. The system is further characterized in that movement of the door panel is configured to be stopped when a characteristic exceeding a pre-determined threshold value is detected by the force-sensing resistor.
In another aspect, safety system for sliding elevator doors is disclosed. The system comprises two sliding door panels moveable in the same direction with different speeds and is characterized in that the system further comprises a force-sensing resistor extending along a side of the slower-moving door panel facing the faster-moving door panel for detecting an object between the two door panels. The system is further characterized in that movement of the door panels is configured to be stopped when a characteristic exceeding a pre-determined threshold value is detected by the force-sensing resistor.
The current safety system is meant for sliding elevator doors. By sliding elevator doors is herein meant doors, in which one or more door panels in an elevator car and on the elevator landing moves in a horizontal direction to open and close the elevator door.
The current system is suited especially for protecting child hands. The gap between a door frame and a door panel, or between two door panels moving in the same direction at different speeds, is so narrow, that only small fingers and hand parts are in danger of being pulled between the moving parts. Since the door panels are heavy and are opened against an automatic closing mechanism, the force used for opening the door is large compared to the hindrance created by child fingers and hands, making their force-based sensing challenging. By detecting a hand is herein meant detecting any part of a hand, such as one or more fingers, or the side of the palm.
However, the system is able to detect any types of objects that exert a force on the force-sensing resistor. Thus, for example pieces of clothing or other items accidentally ending up behind the door frame or between two door panels may be detected. Thus, the system according to the present disclosure is suitable also for avoiding damage to the elevator if hard items are pushed behind the door frame or between two door panels.
By a door frame is herein meant the vertical structure on each side a landing door opening and the corresponding structures in the elevator car. In addition to the door frames, an elevator door comprises door panels moving in a horizontal direction. They are retracted past the door frames away from the door opening during elevator door opening.
In centrally-opening elevator doors, there is at least one door panel moving to each side of the door opening. If there is more than one door panel moving to each side of the opening, the two door panels located closest to the vertical center-line of the opening are the fastest-moving door panels, and the door panels closer to the door frames move slower. It is possible that there are more than two door panels opening to one side of the elevator door. In such a case, each door panel closer to the door frame moves slower than the adjacent one closer to the vertical center-line of the door opening.
Alternatively, elevator doors may be of side-opening type. In such a case, all the door panels move to the same side of the door opening when the door opens. The door panel furthest away from the side to which all the door panels retract during opening is the fastest-moving door panel and the one closest to the side to which all the door panels retract during opening is the slowest. By a slower-moving door panel is herein meant a door panel that moves slower than an adjacent door panel. By a faster-moving door panel is herein meant a door panel that moves faster than an adjacent door panel. For example, in doors with three door panels moving into one direction with different speeds, there is typically a first door panel which is a faster-moving door panel (the fastest-moving door panel) . There may additionally be a second door panel that is a slower-moving door panel relative to the fastest door panel, but simultaneously the faster-moving door panel relative to a third door panel. The third door panel is then the slower-moving door panel relative to the second door panel (the slowest-moving door panel).
To ascertain the opening of the landing door panels only when an elevator car is present, a common door operator is used for both elevator car door panels and landing door panels. The elevator car door comprises a clutch, which opens the locking mechanism of the landing doors, and pulls the landing door panels open together with the elevator car door panels.
By a landing door panel is herein meant a door panel on the landing side of the elevator door. By an elevator car door panel is herein meant a door panel on the elevator car side of the elevator door.
In the system according to the current disclosure, the movement of the door panel is configured to be stopped when force, or change in the force exerted on the force-sensing resistor, exceeding a pre-determined threshold value is detected by the force-sensing resistor. Since the door panel movement is regulated by a door controller, the force-sensing resistor is directly or indirectly connected to the door controller.
By a door operator is herein meant a device comprising a door motor, power electronics and a door controller. By a door controller is herein meant a device comprising the means for speed and position control of the elevator door panels, as well as the door safety features. The door controller may comprise, for example, different types of hardware and software for performing its tasks.
In the current system, a force-sensing resistor is used for detecting an object between a door frame and a door panel, or between two door panels. The system can comprise one or more force-sensing resistors. For example, both of the door frames of an elevator door may comprise at least one force-sensing resistor. If there are two or more door panels opening on one side of the door, the force-sensing resistor may be installed on all but the fastest-moving door panels. A force-sensing resistor is based on a change in resistance upon application of force on the material of the force-sensing resistor.
The force-sensing resistors may be produced of various materials, typically conductive polymers, or mixtures of conductive polymers with other materials. Thus, it is possible to adjust the required force for bringing about the chance in resistance through selecting the appropriate material or material combination. Typically, the resistance of a force-sensing resistor decreases (i.e the voltage increases) with increasing force applied on the force-sensing resistor.
The change in resistance is proportional to the force exerted on the force-sensing resistor. The exact relationship between force and chance in resistance depends on the construction of the force-sensing resistor and can be adjusted. Therefore, the required magnitude of change in resistance necessary to prompt the activation of the system according to the present disclosure, i.e. the stopping of door panel movement, can be selected according to need.
The inventor has found the force-sensing resistors to be well suited for the system according to the present disclosure. They can be manufactured as thin layers and they can be produced in different forms. Further, they are robust in operation and can be used in combination with various coatings, such as rubber or silicone-based material. The coatings may be used to further adjust the responsiveness of the force-sensing resistor. The coatings may alternatively or in addition be used for protecting the force-sensing resistor, or to adjust its thickness. The covering may be applied on the whole surface of the force-sensing resistor. Alternatively, only those areas of the force-sensing resistor can be covered which are prone to be accidentally touched.
In one embodiment, the characteristic is force exerted on the force-sensing resistor, or the characteristic is speed of change in the resistance of the force-sensing resistor. Thus, the magnitude of force exerted on the force-sensing resistor can be used as a characteristic to stop the movement of the door panel. Alternatively, or in addition, the change in the force exerted on the force-sensing resistor can be used as a characteristic to stop the movement of the door panel. Thus, even if the force threshold would not be exceeded, a sudden increase in the force would be, and the movement of the door panels is stopped.
Monitoring the speed of change in the force might be advantageous, for example, if the resistance of the force-sensing resistor changes due to environmental conditions, which is interpreted by the system as change in force exerted on the force-sensing resistor. Such conditions might be, for example, temperature and humidity. It is possible that the idle resistance of the force-sensing resistor changes though ageing. In such a situation, monitoring the speed of chance in the detected force might avoid erroneously triggering the system.
In one embodiment, the force-sensing resistor is rubber-covered. The rubber covering may be attached to the force-sensing resistor. Alternatively, the rubber covering may cover the force-sensing resistor while remaining detached from it.
The length of the force-sensing resistor may be, for example, 500-1,600 mm. In an embodiment, the length of the force-sensing resistor is 800 mm. In an embodiment, the length of the force-sensing resistor is 1,000 mm. In an embodiment, the length of the force-sensing resistor is 1,100 mm.
The width of the force-sensing resistor may be, for example, 10-20 mm. In an embodiment, the width of the force-sensing resistor is 15 mm. Force-sensing resistors are typically less than 3 mm thick. In one embodiment, the thickness of the force-sensing resistor is less than 0.5 mm.
The force-sensing resistor can be attached to the door frame or to the door panel through various means. It can be provided with glue on the side facing the surface on which it is to be attached. Also using double-sided tape between the door frame or the door panel and the force-sensing resistor is an alternative.
The force-sensing resistor is connected to a resistance and/or voltage and/or current measurement device, and when a pre-determined change in resistance and/or voltage and/or current is detected, the door operator is stopped to stop the door panel movement. The system may comprise additional components for adjusting the signal strength, for example. Further, it is possible that if a force exceeding a pre-determined threshold value is detected, an external signal is triggered. The external signal may be, for example, an alarm signal sent to the building central monitoring station. Alternatively, the signal can be sent to an elevator control system for taking into account the delay in the movement of the elevator car in question. In one embodiment, an external signal is triggered when force exceeding a pre-determined threshold value is detected by the force-sensing resistor.
In the current invention, the force-sensing resistor extends along a side of a door frame. Alternatively or in addition, the force-sensing resistor may extend along a side of a door panel. The side, along which the force-sensing resistor extends, faces a door panel. The side, along which the force-sensing resistor extends, and the facing door panel may be parallel. Alternatively, the side along which the force-sensing resistor extends may be at an angle relative to the facing door panel.
In the case the force-sensing resistor extending on a side of a door panel, the door panel which it faces moves faster than the door panel comprising the force-sensing resistor.
In one embodiment, the force-sensing resistor is positioned at a constant distance from the vertical edge of the door frame, or of the slower-moving door panel. In such embodiments, the force-sensing resistor follows the vertical edge of the door panel or the slower-moving door panel. The distance from the edge may be 0-5 mm. From safety point of view, positioning the force-sensing resistor as close as possible to the vertical edge may be beneficial. However, if the force-sensing resistor is very close to the edge, the likelihood of accidental or intentional false alarms increases. The appropriate distance depends, among other things, on the shape and material of the door frame edge. Additionally, the speed and inertia of the door panel might affect the suitable distance.
The current system may be combined with additional safety devices, such as softened, cushioned and/or rounded door frame or door panel edge.
The formation of damage to the object may be reduced by beveling the side of the door frame or the slower door panel. In one embodiment, the side of the door frame facing the door panel, or the side of the slower-moving door panel facing the faster-moving door panel comprises a beveled surface. The beveling gradually narrows the gap between the door panel and the door frame or between two door panels, starting from the edge of the door frame, or of the slower-moving door panel. This might give the child more time to react to the door panel movement, and reduce the abruptness of the hand-squeezing. The beveling can be made in different angles and the length of the beveled surface of the door frame or door panel can vary.
The force-sensing resistor may be positioned at least partly on the beveled surface of the door frame. The force-sensing resistor may be positioned on the beveled surface of the slower-moving door panel. This might allow the force-sensing resistor to be protected from unintentional touching and enable hand-detection before severe damage has been inflicted on the hand. Further, depending on the shape of the beveling, more time might be available for stopping the elevator door panels after detecting an object before the object is damaged. In one embodiment, the force-sensing resistor is positioned on the beveled surface of the door frame or of the slower-moving door panel.
The formation of damage to the hand or other object may be reduced also by rounding the side of the door frame or the slower door panel. In an embodiment, the side of the door frame facing the door panel, or the side of the slower-moving door panel facing the faster-moving door panel comprises a rounded surface. Similarly to beveling, rounding gradually narrows the gap between the door panel and the door frame or between two door panels, starting from the edge of the door frame, and it offers similar advantages. The rounding can be made in different curvatures and the length of the rounded surface of the door frame or door panel side can vary. In an embodiment, the force-sensing resistor is positioned on the rounded surface of the door frame or of the slower-moving door panel.
When force, or speed of change in the force exerted on the force-sensing resistor, exceeding a pre-determined threshold value is detected by the force-sensing resistor, the movement of the door panel is configured to be stopped. In practice, the movement of all door panels is stopped by the door operator. The stopping of the door panel movement can be active, in which case the door operator brakes the movement. Alternatively, the stopping may be passive, in which case the door operator stops the door opening movement. The door panel movement is then stopped by friction of the door components.
The extent of the door panel movement after the object has been detected may affect the damage inflicted on the hand, or other consequences of having an object between moving door parts. Especially, as child hands are small, even movement distances below one centimeter may have a significant influence on the extent of the damage. Therefore, actively braking elevator door panels might be beneficial in some applications. Further, the automatic closing mechanism that ascertains the closure of the doors in the absence of opening force from the door operator, starts to close the door panels immediately, if the door operator becomes idle. Depending on the shape of the door frame edge, the damage done to the object, such as a hand might worsen if, once the object has been pulled between the door panel and the door frame even slightly, a movement in the opposite direction is initiated immediately. Thus, in an embodiment, the door panel is kept in the position at which it was stopped for a pre-determined time, or until a release signal is given.
The most typical situation for a child to have a hand damaged by a moving door panel is when leaning to a landing door of a glass-doored elevator. In one embodiment, the door panel is an elevator landing door panel.
The hand-trapping problem is especially pronounced when the door panels are made of glass. First, they are especially attractive to children to lean on, since they offer a view into the elevator shaft. Second, glass doors are heavy thus have large inertia, making them slow to stop. Further, they require a substantial force for any sideways movement relative to the opening direction that might alleviate the damage inflicted on the hand. Third, glass as material is rigid and, in case of an accident, it does not give in. In one embodiment, the door panel comprises a glass panel. The glass panel allows viewing through the door panel, and the door panel further comprises steel frames around the glass panel, plastic laminated to the glass or other such solutions. In some cases, only the landing door panels comprise a glass panel. Often, however, both landing door panels and elevator car door panels comprise a glass panel.
In one aspect, an elevator comprising a system according to the present disclosure is disclosed. The current system can be used when constructing new elevators, or it can be retrofitted to existing elevators. The current system can be used in the elevator car doors and/or in one or more of the landing doors. For example, all the landing doors can comprise a system according to the present disclosure.
In another aspect, a door frame for a sliding elevator door is disclosed. It is characterized in that it comprises a force-sensing resistor extending along a side of the door frame that is designed to face a door panel for detecting an object between the door panel and the door frame. The force-sensing resistor may be pre-installed to the door frame at the site of manufacture. Thus, the door frame may comprise the force-sensing resistor already when it is transported to the site of elevator installation. Alternatively, the force-sensing resistor may be installed to the door frame at the site of elevator installation.
In another aspect, a door panel for a sliding elevator door is disclosed. It is characterized in that it comprises a force-sensing resistor extending along a side of the door panel that is designed to face another door panel for detecting an object between the door panels. The force-sensing resistor may be pre-installed to the door panel at the site of manufacture. Thus, the door panel may comprise the force-sensing resistor already when it is transported to the site of elevator installation. Alternatively, the force-sensing resistor may be installed to the door panel at the site of elevator installation.
In yet another aspect, a method for installing the safety system according to the present disclosure is disclosed. It is characterized in that it comprises the steps of

a) attaching the force-sensing resistor to the door frame on a side designed to face a door panel, or to a door panel on a side designed to face a faster-moving door panel; and
b) connecting the force-sensing resistor to elevator car door controller for stopping the door panel movement when force exceeding a pre-determined threshold value is detected by the force-sensing resistor.

The method according to the present disclosure can be used when constructing new elevators, or when upgrading existing elevators.
At step a) of the method, the force-sensing resistor is attached to the door frame on a side designed to face a door panel, or to a door panel on a side designed to face a faster-moving door panel. The force-sensing resistor can be attached by different means, such as double-sided tape or glue. The force-sensing resistor may be attached at the site of elevator installation, or at a site of manufacture of the door panels or of the door frames.
At step b), the necessary connections are made to connect the force-sensing resistor with the door controller for bringing about the stopping of the door panel movement when force exceeding a pre-determined threshold value is detected by the force-sensing resistor. The connection may be direct or indirect. The connection maybe formed through various accessory devices, which may, for example, adjust or screen the signal from the force-sensing resistor. The connection may be partially wireless.

DESCRIPTION OF DRAWINGS

The following figures are to be understood as exemplary embodiments of the present disclosure. Further embodiments are envisaged. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described below may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.
All parts of the system and its components are depicted only schematically and their sizes are not drawn proportionally. Further, all additional elevator components are omitted from the figures, although some of them might be present simultaneously with the current system and its components.
Fig. 1 presents a sliding elevator door 1 comprising the system according to the present disclosure viewed from the direction of the elevator landing. The door comprises two centrally-opening landing door panels 2, and the corresponding elevator car door panels (not shown). A door frame 3 is positioned on each side of the door opening.
The system further comprises a force-sensing resistor 4 positioned between the door panel 2 and the door frame 3. As the force-sensing resistor is behind the door frame 3 in fig. 1, it is depicted with a dashed outline. The force-sensing resistor 4 is formed as a strip extending along a side of the door frame 3 from the floor level to a given height. The height to which the force-sensing resistor 4 extends is chosen so that children small enough to have their hands caught between the door frame 3 and the door panel 2 are not able to lean to the door panels 2 above that height. A safe height may be determined by local safety codes.
In the embodiment of fig. 1, the force-sensing resistor 4 is positioned at a constant distance from the vertical edge of the door frame 3.
The connections of the force-sensing resistor 4 to the door controller are omitted for clarity.
Fig. 2A presents a cross section of the elevator door 1 in fig. 1 along the line A-A' . In addition to the landing door panels 2 visible in fig. 1, also the elevator car door panels 2, and a part of the elevator car door frame 3b are depicted. However, the clutch mechanism used for opening both the landing and elevator car door panels 2 simultaneously is omitted.
Both the elevator car and landing door panels 2 are in a closed position, and the cross section of the door frames 3a, 3b is depicted with hatching. The side 5 of the door frame 3a, 3b facing a door panel 2 is visible in this view, and a force-sensing resistor 4 is placed on each of the sides 5 facing a door panel 2.
The force-sensing resistor 4 may be thin, for example approximately 0.5 mm thick, but for visualization purposes, it is drawn thick enough to be viewed in all figures. In the embodiment of fig. 2A, the force-sensing resistor 4 is positioned on each door frame 3, close to the vertical edge 9 of the door frame 3, but so that it is completely on the side 5 facing the door panel 2. Thus, force will only be exerted on the force-sensing resistor 4 if an object, such as a hand or a part thereof, is between the door panel 2 and the door frame 3.
The gap between the door frame 3 and the door panel 2 may be several millimeters in width. Thus, there is some space between the door panel 2 and the force-sensing resistor 4, as depicted in fig. 2A.
Fig. 2B presents an embodiment comprising a four-paneled sliding elevator door 1 similarly to fig. 2A. The elevator car structures are omitted. Force-sensing resistors 4 may or may not be present on the elevator car side of the elevator door 1. The faster-moving door panels 2a are positioned closest to the vertical center-line of the door opening. The slower-moving door panels 2b are symmetrically positioned adjacent to the faster-moving door panels 2a.
Force-sensing resistors 4 are positioned on the door frame 3, on the side 5 facing the slower moving door panels 2b. The positioning of the force-sensing resistors 4 placed on the door frame 3 is similar to that of fig. 2A. Additionally, force-sensing resistors 4 are positioned on the slower-moving door panels 2b, on the side 6 facing the faster-moving door panel 2a. The positioning of the force-sensing resistors 4 on the slower-moving door panel 2b is analogous to that of the force-sensing resistors 4 on the door frame 3. Thus, they are positioned on the side 6 of the slower-moving door panel 2b facing the faster-moving door panel 2a. Each of the force-sensing resistors 4 on the door panels 2 remains between the two moving door panels 2b, 2a.
Additionally, the thickness of the force-sensing resistor 4 may vary, depending on the width of the gap between the door panels 2a and 2b, 2b and 2c, respectively, or between the door frame 3 and the door panel 2c.
Fig. 2C presents a three-paneled side-opening sliding elevator door 1 similarly to figs 2A and 2B. In the elevator door 1, there are three door panels 2a, 2b, 2c moving in the same direction during elevator door opening. The first door panel 2a is the fastest-moving door panel. The second door panel 2b is the slower-moving door panel relative to the first door panel 2a, and the third door panel 2c is the slower-moving door panel relative to the second door panel 2b. They all retract to the same side when the elevator door 1 opens.
Correspondingly, a force-sensing resistor 4 is positioned on only the door frame 3, which the slowest-moving door panel 2c passes when the elevator door opens. Similarly to the door-frame attached force-sensing resistor 4 in figs 2A and 2B, it is positioned on the door panel 2c-facing side 5 of the door frame 3.
Additionally, a force-sensing resistor 4 is positioned on the two door panels 2b and 2c having a faster door panel next to it. Thereon, the force-sensing resistors 4 are positioned on the door-panel facing side 6, as in fig. 2B.
The force-sensing resistor may be identical in all positions, or they can be different. For example, it is possible that the pre-determined threshold value for the force exerted on the force-sensing resistor 4 for stopping the door panel 2a, 2b, 2c movement is different for each force-sensing resistor 4, or for some of them. Further, it is possible that the positioning of the force-sensing resistor 4 in each door frame 3 and/or on each door panel 2a, 2b, 2c varies.
Fig. 3 presents a close-up view of the area A" of fig. 2A and demonstrates the operating principle of the system according to the present disclosure. The arrow indicates the moving direction of the door panel 2 during door opening, and a hand is depicted ending up between the door panel 2 and the door frame 3. A force-sensing resistor 4 is positioned on the side 5 facing the door panel 2 on the door frame 3.
The door frame 3 in fig. 3 has substantially sharp edges on the side 5. The force-sensing resistor 4 is positioned along the side 5. The surface on which the force-sensing resistor 4 is positioned is parallel to the door panel 2.
In fig. 3, fingers are being drawn between the door panel 2 and the door frame 3. The gap is large enough for the fingers to have room in the gap, but it is too small for the palm. The pre-determined threshold value for the force exerted on the force-sensing resistor 4 may be selected so that already a light touch by the fingers would stop the door panel 2 movement. It might also be possible to configure the system according to the present disclosure so that the door panels 2 would stop only when the hand is under pressure, i.e. when it is drawn so far into the gap, that the hand tissues become pressed by the door panel 2 and the door frame 3.
Fig. 4, panels A to E, depicts embodiments of the door frame 3 comprising a force-sensing resistor 4. In all the panels, a section of the door frame 3 is depicted as in fig. 3 and the door panel 2 moves to the left when the door opens. The side 5 of the door frame 3 facing the door panel 2 indicates the orientation of the elevator door in the figure, but the door panel 2 is omitted. Similar embodiments to the ones depicted in fig. 4, panels A to E, are possible in door panels 2 comprising a force-sensing resistor 4.
In panel A, the side 5 of the door frame 3 facing the door panel 2 comprises a beveled surface 7. The force-sensing resistor 4 is positioned on the portion of the side 5 facing the door panel 2 that is parallel to the door panel 2. The beveled surface 7 may allow more time for the object to be pulled away from the gap between the door panel 2 and the door frame 3. In case the object is pulled further between the door panel 2 and the door frame 3, it will touch the force-sensing resistor 4 and when the force exerted by the object on the force-sensing resistor 4 exceeds the pre-determined threshold value, the door panel 2 movement is stopped.
The location of the force-sensing resistor 4 in panel A further might have the advantage that the force-sensing resistor 4 protected from unwanted touching.
In panel B, the side 5 of the door frame 3 facing the door panel 2 comprises a beveled surface 7. The force-sensing resistor 4 is positioned on the beveled surface 7. This might allow the earlier recognition of an object between a door panel 2 and a door frame 3. It would also be possible that the force-sensing resistor 4 is partly on the beveled surface 7 of the side 5 facing the door panel 2.
In panel C, the side 5 of the door frame 3 facing the door panel 2 comprises a rounded surface 8. The function of the rounding is similar to that of beveling, but it further lacks sharp edges that might aggravate the damage on the object.
In the embodiment of panel C, the force-sensing resistor 4 is positioned on partly on the rounded surface 8 and partly on the portion of the side 5 extending parallel to the door panel 2. However, it would be possible that the force-sensing resistor 4 is only on the rounded surface or only on the portion of the side 5 extending parallel to the door panel 2.
Panels D and E are embodiments demonstrating that the system according to the present disclosure may be implemented on different types of door frame 3 profiles. Similar embodiments might be possible on door panels 2 as well.
In panel D, the side 5 of the door frame 3 facing the door panel 2 comprises a beveled surface 7. However, in the embodiment of panel D, the beveled surface 7 is formed on a protrusion 10 from the overall profile of the door frame 3. The protrusion 10 might be an integral part of the door frame 3 or a separate piece. For example, the protrusion 10 may be manufactured from material that is softer than the material used elsewhere in the door frame 3. The force-sensing resistor 4 is positioned on the beveled surface 7.
In panel E, the side 5 of the door frame 3 facing the door panel 2 comprises a protrusion 10, but this time the shape of the protrusion 10 is rectangular in cross section, and the force-sensing resistor 4 is positioned on the surface of the protrusion 10 parallel to the vertical side edge 9 of the door frame 3 on the side of the door opening.

Claims

A safety system for sliding elevator doors (1), the system comprising a sliding door panel (2) and a door frame (3), characterized in that the system further comprises a force-sensing resistor (4) extending along a side (5) of the door frame (3) facing the door panel (2) for detecting an object between the door panel (2) and the door frame, and in that movement of the door panel (2) is configured to be stopped when a characteristic exceeding a pre-determined threshold value is detected by the force-sensing resistor (4).
A safety system for sliding elevator doors (1), the system comprising two sliding door panels (2) moveable in the same direction with different speeds, characterized in that the system further comprises a force-sensing resistor (4) extending along a side (6) of the slower-moving door panel (2b) facing the faster-moving door panel (2a) for detecting an object between the two door panels (2b, 2a), and in that movement of the door panels (2) is configured to be stopped when a characteristic exceeding a pre-determined threshold value is detected by the force-sensing resistor (4).
The system according to claim 1 or 2, wherein the characteristic is force exerted on the force-sensing resistor, or wherein the characteristic is speed of change in the force exerted on the force-sensing resistor.
The system according to any of claims 1-3, wherein the force-sensing resistor (4) is positioned at a constant distance from the vertical edge (9) of the door frame (3), or of the slower-moving door panel (2b).
The system according to any of claims 1-4, wherein the side (5) of the door frame (3) facing the door panel (2), or the side of the slower-moving door panel (2b) facing the faster-moving door panel (2a) comprises a beveled surface (7).
The system according to any of claims 1-5, wherein the force-sensing resistor is positioned on the beveled surface (7) of the door frame (3) or of the slower-moving door panel (2b).
The system according to any of claims 1-6, wherein the thickness of the force-sensing resistor (4) is less than 0.5 mm.
The system according to any of claims 1-7, wherein the force-sensing resistor (4) is rubber-covered.
The system according to any of claims 1-8, wherein an external signal is triggered when force exceeding a pre-determined threshold value is detected by the force-sensing resistor (4).
The system according to any of claims 1-9, wherein the door panel (2) is an elevator landing door panel (2).
The system according to any of claims 1-10, wherein the door panel (2) comprises a glass panel.
An elevator comprising a system according to any of claims 1-11.
A door frame (3) for a sliding elevator door characterized in that it comprises a force-sensing resistor (4) extending along a side (5) of the door frame (3) that is designed to face a door panel (2) for detecting an object between the door panel (2) and the door frame (3).
A door panel (2) for a sliding elevator door, characterized in that it comprises a force-sensing resistor (4) extending along a side (6) of the door panel (2) that is designed to face another door panel (2) for detecting an object between the door panels (2).
A method for installing the safety system according to any of claims 1-11, characteri z e d in that it comprises the steps of
c) attaching the force-sensing resistor (4) to the door frame (3) on a side (5) designed to face a door panel, or to a door panel on a side (6) designed to face a faster-moving door panel; and

d) connecting the force-sensing resistor (4) to elevator car door controller for stopping the door panel (2) movement when force exceeding a pre-determined threshold value is detected with the force-sensing resistor (4).