EP3328777B1

EP3328777B1 - Lock strike plate provided with an emergency unlocking system, and lock-ing device comprising said lock strike plate

Info

Publication number: EP3328777B1
Application number: EP15820647.4A
Authority: EP
Inventors: Stefano ZUCCHETTI
Original assignee: TE Srl
Current assignee: TE Srl
Priority date: 2015-07-30
Filing date: 2015-09-17
Publication date: 2020-06-10
Anticipated expiration: 2035-09-17
Also published as: ITUB20152666A1; WO2017017702A1; EP3328777A1

Description

Field of application of the invention

The present invention refers to the field of lifting systems for people and/or objects comprising a platform movable between at least two positions placed at different levels. The platform comprises, by way of example, at least one support surface preferably horizontally arranged and possibly delimited by one or more lateral walls that support a ceiling. In the latter case, the platform can correspond with a structure usually termed "car".
More precisely, the present invention has application in reference to the lifting systems in which the platform moves within a hoistway accessible through suitable doors respectively placed at the platform stop positions. By way of example, with reference to an elevator comprising a car moving in a hoistway that connects different floors of a building, the abovementioned access doors to the hoistway correspond with so-called "landing doors".
Among the lifting systems of the aforesaid type, those where the present invention has application comprise, for each access door to the hoistway, a device for locking the door which prevents the access to the hoistway when the platform is not in the corresponding stop position (i.e., with reference once again to the example of an elevator, when the car is not at the floor).
In order to facilitate the exposition, hereinbelow in the present description, with the expression "elevator platform" it is intended to identify any lifting system having the abovementioned characteristics. Likewise the access doors to the hoistway of an elevator platform will be indicated hereinbelow in the present description with the expression "landing doors".
The devices for locking the landing doors generally comprise a first component, defined "lock", including a translatable bolt, and a second component, defined "lock strike plate", including a seat in which the bolt is at least partially housable. Said housing seat will be indicated hereinbelow in the present description with the expression "bolt bushing". With reference, by way of example, to swing landing doors, the safety lock is usually installed in the leaf of the door (preferably a single leaf door) and the lock is installed in the frame of the door. The at least partial housing of the bolt in the bolt bushing prevents the rotation of the leaf and consequently the opening of the door.
The present invention refers to a lock strike plate of a device for locking a landing door of an elevator platform, provided with an emergency unlocking system. The present invention also refers to a locking device comprising said lock strike plate.

Review of the prior art

As mentioned above, the devices for locking the landing doors of an elevator platform comprise a lock usually installed in the door frame and a lock strike plate usually installed in the door leaf. When the landing door is closed, the lock and the lock strike plate are opposite in such a manner that the bolt of the lock is at least partially housed in the bolt bushing of the lock strike plate. In particular, with reference to when the landing door is closed, the bolt moves between at least one first position at which the bolt is at least partially housed in the bolt bushing, and a second position at which the bolt is not housed in the bolt bushing. Incidentally, when the bolt is in the first position, it is opposed to a rotation of the door leaf, thus preventing the opening of the landing door and consequently the access to the hoistway of the elevator platform. When the bolt is in the second position, it lies outside the lock strike plate so as to allow the rotation of the door leaf and consequently the opening of the landing door. Hereinbelow in the present description, said first position will be indicated with the expression "locked position" and said second position will be indicated with the expression "unlocked position".
In current locking devices, the lock usually comprises a spring which keeps the bolt in the locked position (so as to prevent the opening of the landing door when the latter must remain closed). The lock is also provided with a lever system which, when the car arrives at the floor, makes the bolt move to unlocked position, retracting it into the lock. Usually, it is the car itself that, upon arriving at the floor, actuates the lever, unlocking the door. Under normal operating conditions, a landing door is therefore always kept shut by the locking device except when the car is stationary at the floor.
The current locking devices comprise an emergency unlocking system installed in the lock. Said unlocking system usually includes a pin accessible from outside the lock and rotationally coupled to the aforesaid lever. The pin is rotatable around its longitudinal axis and is coupled to the lever in such a manner that a rotation of the pin causes a translation of the bolt. The pin generally has a triangular cross section (for which reason it is also known as "unlocking triangle") and is rotatable by means of a tubular key. The rotational coupling between the unlocking triangle and the lever is obtained, by way of example, by means of a gear system.
The emergency unlocking system allows the opening of a landing door even when the car of the elevator platform is not at the floor. Such need may arise if it is necessary to carry out ordinary or special maintenance operations in the hoistway of the elevator platform or on the car, outside the car itself.
In the current locking devices, the unlocking triangle may be difficult to access. Given that the emergency unlocking system is installed in the lock and given that the lock is installed in the frame of a landing door, it may happen that the unlocking triangle is covered by decorative panels installed over the frame. In these cases, the unlocking triangle is not accessible nor visible to a maintenance man or to a rescuer. If this should happen, whenever a landing door must be unlocked, it is therefore necessary to force the door open, damaging the door itself and/or the locking device.
In addition, the presence of the emergency unlocking system increases the bulk of the lock. This constitutes a drawback if the space that can be occupied in the uprights of the landing door frame is extremely limited. By way of example, this happens when the hoistway of the elevator platform, rather than being made of bricks, is a compact structure made of steel and polymer panels, preferably transparent. Examples of locking devices according to the state of the art are disclosed in DE60214712T , DE4033840 , US4181338 , FR2931184 .

Objects of the invention

The object of the present invention is to overcome the aforesaid drawbacks, by indicating an emergency unlocking system that, in addition to being more accessible than the current unlocking systems, requires less space.
Such object is pursued by means of a lock strike plate coupled to a locking device for landing doors of elevator platforms, which includes a seat (hereinbelow in the present description, it will be defined "bolt bushing") in which the bolt of said locking device is at least partially housable.
The aforesaid lock strike plate includes an emergency unlocking system which comprises:

ejection means movable between at least one first position (engagement position) at which said ejection means lie outside the bolt bushing, and a second position (disengagement position) at which said ejection means are at least partially housed in the bolt bushing;
means suitable for moving the ejection means between the engagement position and the disengagement position.

When the bolt is housed in the bolt bushing (and therefore the ejection means are in the engagement position), a movement of the ejection means from the engagement position to the disengagement position determines the exit of the bolt from the bolt bushing and hence the unlocking of the landing door.
In conclusion, the invention regards a lock strike plate provided with an emergency unlocking system. Advantageously, given that the lock strike plates of the locking devices are usually installed in the leafs of the landing doors, there are no longer problems with the bulk of the emergency unlocking system, nor problems of accessibility of the aforesaid ejection means. First of all, the leafs of the landing doors in fact occupy a volume that cannot be reduced beyond a certain limit, since the width of the access opening to the hoistway and consequently to the car of the elevator platform would also be reduced.
This is particularly true in regard to swing doors. In addition, the volume of the leafs of the landing doors, if not occupied in part by the lock strike plate, object of the invention, could not otherwise be exploited. Finally, the "landing-floor-side" accessible surface of a leaf of a door is clearly greater than that of the frame thereof. Even if decorative cover panels are installed over the door leaf, with respect to current locking devices, it is therefore more probable that one can identify positions where to place the lock strike plate so that the means for moving the unlocking system are always accessible to a maintenance man or to a rescuer.
Advantageously, the lock strike plate, object of the invention, can also be coupled to the existing locks already provided with an emergency unlocking system of their own. In particular, if the unlocking triangle of a lock is no longer accessible to a maintenance man or to a rescuer (by way of example, as mentioned above, due to the application of a cover panel), in order to equip the device for locking the landing door with an accessible emergency unlocking system it is sufficient to replace the known lock strike plate with the lock strike plate that is the object of the invention.
The object of the present invention is therefore a lock strike plate comprising a bolt bushing characterized in that it comprises an emergency unlocking system which includes:

ejection means movable between at least one engagement position at which said ejection means lie outside said bolt bushing, and one disengagement position at which said ejection means are at least partially housed in said bolt bushing; and
means for moving said ejection means between said engagement position and said disengagement position.

Further innovative characteristics of the present invention are described in the dependent claims.
According to one aspect of the invention, the moving means comprise:

a lever including a bar rotatable around a fulcrum, said ejection means being situated at the point of application of the mechanical resistance of said lever, a rotation of the bar around the fulcrum determining a movement of the ejection means between the engagement position and the disengagement position;
a pin accessible from outside the safety lock and rotatable around a longitudinal axis thereof, the pin being rotationally coupled to said bar.

A rotation of the pin therefore determines a rotation of the bar around the fulcrum and consequently a movement of the ejection means between the engagement position and the disengagement position.
Preferably, the pin has a triangular cross section at least at a terminal section accessible from outside the safety lock. By way of example, the pin is rotatable by means of a tubular key (in a manner entirely analogous to an unlocking triangle).
According to another aspect of the invention, the longitudinal (rotation) axis of the pin is situated at the fulcrum of the lever.
According to another aspect of the invention, the pin is integrally connected to the bar of the lever.
Alternatively, the rotational coupling between the pin and the bar can be obtained, by way of example, by means of a gear system.
The lever of the emergency unlocking system is therefore a class 3 lever in which the driving force, being applied by means of a tubular key fittable on the pin, is in fact a torque transmitted to the bar at the fulcrum. For this reason, the bar of the lever will also be indicated as a "cam" hereinbelow in the present description.
According to another aspect of the invention, the ejection means comprise a first tooth integrally connected with the bar of the lever.
Preferably, the fulcrum of the lever is situated at one end of the bar and the first tooth is situated at the opposite end.
Moving from the engagement position to the disengagement position, the first tooth pushes against the bolt and ejects it from the bolt bushing, unlocking the landing door. The mechanical resistance of the lever is therefore constituted by the inertia of the first tooth and by the resistance exerted by the bolt against the ejection from the bolt bushing.
According to another aspect of the invention, the ejection means comprise a translatable sliding block in the bolt bushing, a rotation of the bar around the fulcrum determining a thrust of the sliding block from the engagement position to the disengagement position.
Moving from the engagement position to the disengagement position, the bar pushes against the sliding block, which in turn pushes against the bolt and ejects it from the bolt bushing, unlocking the landing door. The mechanical resistance of the lever is therefore constituted by the inertia of the sliding block and by the resistance exerted by the bolt against the ejection from the bolt bushing.
Preferably, the fulcrum of the lever is situated at one end of the bar and the bar abuts against the sliding block at the opposite end.
According to another aspect of the invention, the emergency unlocking system comprises elastic means that tend to move the ejection means from the disengagement position to the engagement position.
Advantageously, due to the presence of the elastic means, once the unlocking of the landing door has been carried out, the emergency unlocking system automatically returns into the configuration preceding the unlocking. Once the maintenance or rescue operation has ended, there is therefore no risk that the landing door remains mistakenly unlocked even when the car of the elevator platform is not at the floor, due to the ejection means remaining in the disengagement position.
By way of example, the elastic means comprise a torsion spring installed in the bar of the lever, preferably at the fulcrum.
According to another aspect of the invention, the emergency unlocking system also comprises:

means suitable for sending a signal perceptible by additional devices;
means for activating said signaling means at least when the ejection means are in the disengagement position.

Advantageously, once the unlocking of the landing door has been carried out, so long as the ejection means remain in the disengagement position, a signal to such regard is sent to the maintenance man or to the rescuer. Therefore if, after the maintenance or rescue operation has terminated, the landing door remains erroneously unlocked due to the ejection means remaining in the disengagement position, the signaling means signal this malfunction to the maintenance man or to the rescuer.
According to another aspect of the invention, the signaling means comprise an electrical contact which is activated by means of a switch, the activation means comprising a second tooth integrally connected to the bar of the lever, a rotation of said bar determining an actuation of said switch (and hence an actuation of the electrical contact) by means of said second tooth.
By way of example, with reference to a button switch, when the ejection means are in the engagement position, the button of the switch is not pressed and the electrical contact is open. When the ejection means move from the engagement position to the disengagement position (i.e. with a rotation of the bar of the lever), the second tooth pushes against the button, pressing it. The pressing of the button determines the closure of the electrical contact and the sending of a signal indicating that the ejection means remain in the disengagement position.
If the ejection means include the first tooth, the latter is preferably at one end of the bar of the lever and the second tooth is situated at the opposite end.
According to another aspect of the invention, said signaling means comprise means for stopping a car of an elevator platform at the unlocking of the device for locking a landing door to which the lock strike plate, object of the invention, can be coupled.
Preferably, the signal sent by the signaling means is an electrical signal that reaches a controller of the car moving means, stopping them. In other words, so long as the ejection means remain in the disengagement position, the car of the elevator platform advantageously stays where it is. Therefore there is no risk that the car starts to move if the maintenance man or rescuer erroneously shuts the landing door after having entered the hoistway, before the appropriate movable stops have been activated/readied. In such event, the car could in fact crush the maintenance man or rescuer (if he were situated in the pit/base of the hoistway) or make him hit against the top of the hoistway (if he were situated on the roof of the car).
Another object of the invention is a device for locking a landing door of an elevator platform comprising a lock coupled to a lock strike plate according to the present invention.
In particular, the locking device comprises a lock and lock strike plate, the lock comprising a bolt, the lock strike plate comprising a bolt bushing in which the bolt is at least partially housable,
the bolt being translatable between at least one locked position in which it is at least partially housed in the bolt bushing, and an unlocked position in which it is outside the bolt bushing,
in which bolt bushing, according to the invention, the lock strike plate includes an emergency unlocking system comprising:

ejection means movable between at least one engagement position in which they lie outside the bolt bushing, and one disengagement position in which they are at least partially housed in the bolt bushing;
means for moving the ejection means between the engagement position and the disengagement position.

Brief description of the figures

Further objects and advantages of the present invention will become clearer through the following detailed description of an embodiment thereof and through the enclosed drawings, given as a merely explanatory and non-limiting example, in which:

Figures 1 and 2 show, in perspective view, the lock strike plate according to the present invention;
Figures 3 and 4 show, in perspective view, the lock strike plate of figures 1 and 2 in an unlocked configuration of a landing door in which the lock strike plate is installed;
Figure 5 shows, in perspective view, a variant of the lock strike plate of figures 1 and 2;
Figure 6 shows, in perspective view, the variant of figure 5 in an unlocked configuration of the landing door;
Figure 7 shows, in side plan view, a device for locking a landing door comprising the lock strike plate of figures 1 and 2.

Detailed description of several preferred embodiments of the invention

Hereinbelow in the present description, one figure may also be illustrated with reference to elements not expressly indicated in that figure but in other figures. The scale and proportions of the various depicted elements do not necessarily correspond to the actual scale and proportions.
Figures 1 and 2 show a lock strike plate 1 which can be coupled to a lock of a device for locking a landing door of an elevator platform. The lock strike plate 1 comprises an element 2 including, by way of example, two nearly rectangular plates 3 and 4 orthogonally joined to each other at a respective long edge so as to give an L-shaped cross section to the element 2. The plate 3 comprises a preferably circular through hole 5 from whose edge a preferably cylindrical wall 6 rises, such wall 6 orthogonally arranged to the plate 3 on the side opposite the plate 4. The hole 5 and the wall 6 act as an at least partial housing seat of a bolt of a lock to which the lock strike plate 1 can be coupled. The hole 5 and the wall 6 therefore identify a bolt bushing 7. The latter preferably comprises a rod 8 with preferably circular cross section integrally connected to the plate 4 at a support element 9. The rod 8 goes through the hole 5 and the wall 6 preferably for the entire height of the latter. In particular, the rod 8 is preferably orthogonally arranged to the plate 3 and still more preferably at the longitudinal symmetry axis of the wall 6. The rod 8 acts as a translation guide of the bolt in the bolt bushing 7. More precisely, the bolt comprises a seat in which the rod 8 is at least partially housable. During a translation of the bolt in the bolt bushing 7, the rod 8 translates in said seat in the bolt.
The lock strike plate 1 comprises an emergency unlocking system 10 including a cam 11 connected to the plate 4 at its lobe 12. The connection between the plate 4 and the cam 11 is such that the latter is rotatable, with respect to the element 2, in a plane preferably parallel to the plate 4. The system 10 also comprises a pin 13 preferably orthogonally arranged to the plate 4 and rotationally coupled to the cam 11. The pin 13 is connected to the element 2 so as to be rotatable around its longitudinal axis with respect to the plate 4. By way of example, the pin 13 is placed at the rotation axis of the cam 11 and is integrally connected to the latter at the lobe 12. As shown in figure 7, the plate 4 comprises a through hole 20 preferably centrally traversed by the pin 13. Due to the hole 20, the pin 13 is therefore accessible on the side opposite the plate 3 with respect to the plate 4 (i.e. from outside the lock strike plate 1). By way of example, analogous to the unlocking triangles, the pin 13 has a nearly triangular cross section at its terminal portion 21 starting from the free end thereof, i.e. starting from the end opposite that at which the pin 13 is integrally connected to the cam 11. The pin 13 is therefore rotatable around its longitudinal axis by means of a tubular key.
In an alternative embodiment of the lock strike plate 1 not shown in the figures, the pin 13, rather than being integrally connected to the cam 11, is rotationally coupled to the latter by means of a gear system.
As can be observed in figure 2, the cam 11 is integrally connected to a first tooth 22 at its end 23 opposite the lobe 12. By way of example, the tooth 22 is slightly tilted with respect to the longitudinal extension of the cam 11 and, in the configuration shown in figures 1 and 2, lies outside the bolt bushing 7.
Figures 3 and 4 show the safety lock 1 in a configuration that differs from the one shown in figures 1 and 2 due to the fact that the tooth 22 is housed in the bolt bushing 7 following a rotation of the cam 11 around its own axis. By means of the pin 13, the cam 11 is therefore rotatable between at least one first position (previously denominated "engagement position") at which the tooth 22 lies outside the bolt bushing 7, and a second position (previously denominated "disengagement position") at which the tooth 22 is at least partially housed in the bolt bushing 7. The cam 11 and the pin 13 therefore act as means for moving the tooth 22 between the aforesaid positions.
As can be observed in figure 1, when the tooth 22 is in the engagement position, the cam 11 is preferably situated in abutment against the support 9 of the rod 8.
As can be observed in figure 3, when the tooth 22 is in the disengagement position, the cam 11 is preferably situated in abutment against the plate 3.
The system 10 comprises a torsion spring (not shown in the figures) that tends to make the cam 11 rotate in such a manner as to move the tooth 22 from the disengagement position to the engagement position. In other words, the torsion spring tends to hold the lock strike plate 1 in the configuration shown in figures 1 and 2. Preferably, the torsion spring is mounted in the cam 11 at the lobe 12. The components of the lock strike plate 1 are preferably metallic.
With regard to the operation of the lock strike plate 1, when the landing door is locked, the bolt of the lock coupled to the safety lock 1 is in locked position (i.e. it is housed in the bolt bushing 7) and the tooth 22 is in the engagement position (i.e. it lies outside the bolt bushing 7). In this configuration, the landing door is therefore locked by the bolt.
When it is necessary to unlock the landing door, the pin 13 is made to roll around its axis by means of a suitable tubular key. Due to said rotation, the tooth 22 pushes against the bolt, ejecting it from the bolt bushing 7. When the tooth 22 reaches the disengagement position, the bolt is in the unlocked position (i.e. it lies outside the bolt bushing 7) and the landing door can be opened. The tooth 22 therefore acts as a means for ejecting the bolt 42 (figure 7) from the bolt bushing 7.
The cam 11 acts as the bar of a class 3 lever whose fulcrum is situated at the rotation axis of the cam 11 (i.e. at the pin 13). The driving force of the lever is applicable to the bar by means of the aforesaid tubular key. It is therefore a torque that, in the current case, is transmitted to the bar at the fulcrum. The mechanical resistance of the lever is constituted by the inertia of the tooth 22 and by the resistance exerted by the bolt against the ejection from the bolt bushing 7.
The lock strike plate 1 is preferably installable in the leaf of a landing door. Still more preferably, the lock strike plate 1 can be installed in such a manner that the plate 3 (together with the bolt bushing 7) fits in the edge of the door leaf and the plate 4 (together with the pin 13) lies in the lateral wall of the "landing-floor-side" of the door leaf. In such a configuration, the pin 13 is easily accessible to a maintenance man or to a rescuer who must perform an operation on the elevator platform from outside the hoistway (i.e., from the landing floor). At the end of the maintenance or rescue operation, after having extracted the tubular key, the above mentioned torsion spring drives the lock strike plate 1 back into the configuration shown in figures 1 and 2 (so as to allow the locking of the landing door by the bolt).
In an alternative embodiment of the lock strike plate 1, not shown in the figures, the unlocking system comprises, in place of the tooth 22, a sliding block translatable in the bolt bushing 7. Similarly to what previously written with reference to the tooth 22, the sliding block is translatable between at least one engagement position in which the sliding block lies outside the bolt bushing 7, and one disengagement position in which the sliding block is at least partially housed in the bolt bushing 7. The rotation of the cam 11 around its own axis makes the sliding block move between aforesaid positions.
With regard to the operation, when the landing door is locked, the bolt of the lock coupled to the lock strike plate 1 is in the locked position and the sliding block is in the engagement position. In this configuration the landing door is therefore locked by the bolt. Whenever it is necessary to unlock the landing door, the pin 13 is made to rotate around its own axis by means of a suitable tubular key. Due to said rotation, the cam 11 pushes against the sliding block preferably at the end 23 thereof. The sliding block in turn pushes against the bolt, ejecting it from the bolt bushing 7. When the sliding block reaches the disengagement position, the bolt is in the unlocked position and the landing door can therefore be opened. Analogous to the tooth 22 of the safety lock 1, the sliding block acts as a means for ejecting the bolt from the bolt bushing 7.
Figures 5 and 6 show a lock strike plate 30 which differs from the lock strike plate 1 due to the fact that it comprises, in addition to the above-described components, an apparatus 31 including an electrical contact which can be actuated by means of a switch 32 preferably of button type. The apparatus 31 comprises elastic or magnetic means which bring back(reset) the button to not actuated position and it is connected, by way of example, to a controller for the moving means of the elevator platform car at a landing door on which the lock strike plate 30 is installed. Pressing the button 32 determines the actuation of the electrical contact and the sending of an output signal to said controller, by which the movement of the car is prevented. So long as the electrical contact is actuated (hence so long as the button is pressed), the car stays where it is.
The apparatus 31 acts as a means for signaling the presence of the tooth 22 in the disengagement position, i.e. as a means for signaling that the landing door, in which the lock strike plate 30 is installed, is unlocked. In addition, since the actuation of the electrical contact prevents the movement of the car, the apparatus 31 acts as a means for stopping the car when the landing door, in which the lock strike plate 30 is installed, is unlocked.
Preferably, the button 32 is in contact with the cam 11, which, by means of a suitable shape of its profile, determines the actuation of the button when the lock strike plate is in disengagement position.
In the configuration shown in figure 5, the tooth 22 is in the engagement position and the button 32 is not pressed.
Alternatively, the emergency unlocking system of the aforesaid lock strike plate 33 differs from the unlocking system 10 of the lock strike plate 1 also due to the fact that it comprises a second tooth 34 integrally connected with the cam 11 at the lobe 12. The tooth 34 is connected to the cam 11 in such a position to lie in proximity to the button 32.
Figure 6 shows the lock strike plate 30 in a configuration that differs from that shown in figure 5 due to the fact that, following a rotation of the cam 11 around its own axis, the tooth 22 is in the disengagement position and the button 32 is pressed by the tooth 34. By means of the cam 11, the tooth 34 is therefore movable between at least one first position at which it lies in proximity to the not-pressed button 32, and a second position at which it is in contact with the pressed button 32.
With regard to the operation of the lock strike plate 30, when the landing door is locked, the bolt of the lock coupled to the lock strike plate 30 is in the locked position and the tooth 22 is in the engagement position. In this configuration, the landing door is therefore locked by the bolt.
When it is necessary to unlock the landing door, the pin 13 is made to rotate around its own axis by means of a suitable tubular key. Due to said rotation, the tooth 22 reaches the disengagement position (by ejecting the bolt from the bolt bushing 7) and the tooth 34 pushes against the button 32, pressing it (and hence actuating the electrical contact of the apparatus 31). The tooth 34, through the cam 11, therefore acts as a means for activating the apparatus 31.
After having performed the unlocking of the landing door, so long as the tooth 22 remains in the disengagement position, the button 32 remains pressed and the apparatus 31 prevents the movement of the car. At the end of the maintenance or rescue operation, after or at the same time as the return of the tooth 22 in the engagement position, the abovementioned elastic or magnetic means bring the button 32 back into the configuration where it is not pressed, so as to allow the movement of the car.
Figure 7 shows a device 40 for locking a landing door of an elevator platform. The device 40 comprises the lock strike plate 1 (or, in an entirely equivalent manner, the lock strike plate 30) coupled to a lock 41 of known type. The coupling between the lock strike plate 1 or 30 and the lock 41 consists in the fact that the lock 41 comprises a bolt 42 translatable in the bolt bushing 7. More precisely, the bolt 42 is at least partially housed in the bolt bushing 7 when it is in the locked position and lies outside the bolt bushing 7 when it is in the unlocked position.
On the basis of the description provided for a preferred embodiment, it is obvious that some changes can be introduced by the person skilled in the art without departing from the scope of the present invention, as defined by the following claims.

Claims

Device (40) for locking a landing door of an elevator platform, said device (40) comprising a lock (41) provided with a bolt (42) and a lock strike plate (1, 30) provided with a bolt bushing (7) to be coupled with a said lock said device (40) being characterized in that it further comprises an emergency unlocking system (10, 33) for said lock, which includes:
• means (22) for ejecting said bolt from said bolt bushing, movable between at least one engagement position at which said ejection means (22) lie outside said bolt bushing (7), and one disengagement position at which said ejection means (22) are at least partially housed in said bolt bushing (7), and

• means (11, 13) for moving said ejection means (22) between said engagement position and said disengagement position.
Device (40) according to claim 1, characterized in that said moving means (11, 13) comprise:
• a lever including a bar (11) rotatable around a fulcrum, said ejection means (22) being situated at the point of application of the mechanical resistance of said lever, a rotation of said bar (11) around the fulcrum determining a movement of said ejection means (22) between said engagement position and said disengagement position;

• a pin (13) accessible from outside said safety lock (1, 30) and rotatable around a longitudinal axis thereof, said pin (13) being rotationally coupled to said bar (11).
Device (40) according to claim 2, characterized in that the longitudinal axis of said pin (13) is situated at the fulcrum of the lever.
Device (40) according to claim 3, characterized in that said pin (13) is integrally connected to said bar (11).
Device (40) according to claim 2, characterized in that said ejection means (22) comprise a first tooth (22) integrally connected to said bar (11).
Device (40) according to claim 1, characterized in that said emergency unlocking system (10, 33) comprises elastic means that tend to move said ejection means (22) from said disengagement position to said engagement position.
Device (40) according to claim 2, characterized in that said emergency unlocking system (33) comprises:
• means (31, 32) suitable for sending a signal perceptible by additional devices;

• means (34) for activating said signaling means (31, 32) at least when said ejection means (22) are in said disengagement position.
Device (40) according to claim 7, characterized in that said signaling means (31, 32) comprise an electrical contact which can be actuated by means of a switch (32), said actuation means (34) comprising a second tooth (34) integrally connected to said bar (11), a rotation of said bar (11) determining an actuation of said switch (32) by means of said second tooth (34).
Device (40) according to claim 8, characterized in that said signaling means comprise means for stopping a car of an elevator platform.