Lift kit and associated elevator

The use of rigid U-shaped chains with bottom actuation and a structural frame in elevator systems addresses cable wear and hydraulic risks, improving stability and reliability with reduced maintenance needs and partial redundancy.

FR3153089B1Active Publication Date: 2025-09-19SERAPID FRANCE
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Patent Information

Application Number
FR2023009727
Authority / Receiving Office
FR · FR
Patent Type
Patents
Current Assignee / Owner
Filing Date
2023-09-14
Publication Date
2025-09-19
Estimated Expiration
2043-09-14

AI Technical Summary

Technical Problem

Existing elevator systems face issues with cable wear, rapid degradation, environmental risks from hydraulic fluids, and structural deformations due to pulley attachments, necessitating a safer and more reliable lifting mechanism.

Method used

A lifting kit using rigid U-shaped chains actuated from the bottom, with electric motors and pinions, and a structural frame for improved stability and redundancy, featuring accessible maintenance points and remote-controlled release mechanisms.

Benefits of technology

Enhances elevator stability, reduces maintenance frequency, and ensures continued operation even with partial component failure, minimizing environmental impact and structural deformation.

✦ Generated by Eureka AI based on patent content.

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Patent Text Reader

Abstract

An elevator lifting kit, comprising:- a structural frame (105), configured to be fixed to an elevator shaft wall,- a platform (1), guided in translation along the structural frame (105), configured to carry a load to be raised and / or lowered,- at least one counterweight (9) or balancing mass, connected to the platform (1) so that the counterweight (9) or balancing mass lowers when the platform (1) rises, and rises when the platform (1) lowers,characterized in that it comprises two lifting devices (103), each comprising:- an electric motor (51) driving a pinion (50), - a rigid chain (7), arranged in a U-shape, the pinion (50) engaging with the rigid chain (7) and driving it. Abstract figure: [Fig. 2]
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Description

Title of the invention: Lifting kit and associated elevator Technical field

[0001] The present invention relates to the field of elevators and hoists, more particularly to elevator and hoist lifting kits, i.e. the motor and guide assembly enabling their operation. The subject of the invention is the inclusion of rigid chains in this lifting kit, in particular in place of cables, hydraulic cylinders, and / or pulleys to transmit force and movement to a platform carrying the cabin or the load. Prior art

[0002] Elevators and hoists are most often set in motion, in the general case, by motor systems, counterweights or balancing masses, cables, hydraulic cylinders and pulleys possibly forming a pulley system. The pulley system and counterweights also reduce the effort required to raise the load, and therefore the motor power required.

[0003] Passenger elevators in particular, but also goods elevators, are subject to regional standards ensuring the safety of the people and loads transported, over a long lifespan with numerous usage cycles (hundreds of thousands of cycles or even millions).

[0004] The EN81 family of standards, which governs elevator safety in Europe, recommends the implementation, among other things, of means to prevent uncontrolled movements, excessive speeds and stops outside the intended positions, obstacle detectors for closing doors and overloads, devices for locking car doors between stops, the use of fireproof materials, etc.

[0005] In particular, the EN81-20 standard and several other regional and national standards provide that elevators must have redundancy in their motor components, for increased safety in the event of component failure.

[0006] The transmission of force in cable elevators is generally carried out by at least two parallel metal cables which pass through pulleys, connected at their respective ends on the one hand to the plate carrying the load and on the other hand to a motorized drum. A balancing mass is connected via a second cable to the same drum. Since the cables can only transmit a force in traction, pulleys forming a return of said cables are generally located at the top of the installation.

[0007] The fixing to the building of the pulleys or the drum in the high position further implies a solid and durable fixing, in the form of a bracket or attachment to a ceiling of the elevator shaft, or on the floor of a machine room located above the elevator shaft. The forces at the pulleys can, in the case of a jib-shaped attachment, cause deformations and tearing at the base of the jib.

[0008] The cables also wear out relatively quickly due to their repeated elastic deformations when passing through the pulleys or when being wound / unwound around the drum. Their inspection and replacement are delicate operations.

[0009] The transmission of the force of hydraulic elevators is generally done by means of one or two hydraulic cylinders, of at least two telescopic sections, which can be reeved at the head by a flexible transmission (chain or cable) in order to multiply the forward speed - since this is typically low - and limit the dead travel - since this is typically long. The integration of hydraulic cylinders requires drilling generally over several meters under the shaft or the building, this having strong geotechnical implications, especially on existing structures. The presence of a significant quantity of oil poses a significant risk of environmental contamination, sometimes requiring sealing of the pit and health precautions for the workers. In addition, the vapors from these hydraulic oils raise increasingly pressing health issues.

[0010] There is therefore a need for a lifting kit which does not have the disadvantages previously mentioned. Summary of the invention

[0011] In order to meet this need, the invention proposes an elevator lifting kit, comprising:

[0012] - a structural frame, configured to be fixed to an elevator shaft wall,

[0013] - a plate, guided in translation along the structural frame, configured to carry a load to be raised and / or lowered,

[0014] - at least one counterweight or balancing mass, connected to the plate so that the counterweight or balance mass lowers when the platter rises, and rises when the platter lowers.

[0015] The lifting kit according to the invention is characterized in that it comprises two lifting devices, each comprising:

[0016] - an electric motor driving a pinion,

[0017] - a rigid chain, arranged in a U, the sprocket engaging with the rigid chain and setting it in motion, the pinion being located at the bottom in the structural frame.

[0018] The use of rigid U-shaped chains allows actuation from the bottom of the chain and therefore of the plate. Thus, the force returns are located at the lower base, at the bottom of the elevator shaft, while no or fewer elements are arranged at the top of the chassis. Stability is thus improved, and the forces and torques exerted on the chassis are lower at equal load.

[0019] The elevation kit according to the invention may further have one or more of the following characteristics, taken alone or in combination.

[0020] It may also include for each lifting device: - separately reversible means of fixing the rigid chain to the chainring, - separately reversible means of fixing the rigid chain to the counterweight or balancing mass.

[0021] It is then possible to keep the associated elevator functional when one of the lifting devices suffers a breakdown, possibly in a degraded mode.

[0022] Each lifting device may comprise an opening for access to the rigid chain, located in the lower part of the U formed by the rigid chain, at the level of the curved portion for extracting and / or replacing the rigid chain.

[0023] Extraction of the rigid chain is then easy, and the opening is accessible to the operator.

[0024] The kit may include for each rigid chain a tensioning device arranged at the bottom of the U formed by the rigid chain.

[0025] The tensioning device tensions and guides the chain in the bottom of the U that it forms, which reduces the repetitive noise and shocks that the rigid chain would generate when operating in the absence of such a tensioner.

[0026] The kit may include at least one device configured to selectively release the plate or counterweight from the rigid chain of a first lifting device, and to prevent simultaneous release of the rigid chain of the second lifting device when the rigid chain of the first lifting device is released from the load.

[0027] This device then makes it possible to avoid the complete release of the plate or the counterweight of the two chains at the same time, which would be a potentially destructive case of serious failure.

[0028] At the level of the plate, the lifting kit may comprise a three-state mechanical device, configured to selectively release the plate from one of the two lifting devices while preventing the simultaneous release of the other lifting device, the three states of the device corresponding to the respective configurations where: - the two rigid chains are secured to the plate in the first state, - a first rigid chain is released from the plate and the second rigid chain is secured to the plate in the second state, - the second rigid chain is released from the plate and the first rigid chain is secured to the plate in the third state.

[0029] The kit may comprise at the counterweight an electric remote-controlled device configured to selectively release the counterweight from one of the two lifting devices.

[0030] The remote-controlled device may further have manual activation means that can be operated manually or by means of a tool to selectively release the counterweight of one of the two lifting devices.

[0031] The mechanical device at the cabin or platform is always accessible. On the other hand, the counterweight may be located behind the cabin or platform, and thus be inaccessible. Consequently, the mechanical device, which is more reliable and less susceptible to failure, is arranged at the cabin. The remote-controlled device, which can be operated remotely, is arranged at the counterweight.

[0032] The chassis may comprise vertical guide profiles in which at least one rectilinear portion of the rigid chain forming a U is housed.

[0033] The structural frame may have a power take-off, and blades for locking the rigid chain of at least one of the lifting devices when inserted into the rigid chain in cooperation with the power take-off.

[0034] Finally, the invention also relates to an elevator comprising such an elevation kit. Brief description of the figures

[0035] Other advantages and characteristics of the invention will appear on reading the description of the figures below, among which: - [Fig.l] is a schematic perspective view of an elevator lifting kit according to the invention, - [Fig.2] is an exploded and perspective representation of the main blocks of the elevation kit of [Fig.l], - [Fig.3] is a partial sectional representation of the bottom of one of the lifting devices of the lifting kit of figures 1 and 2, - [Fig.4] is a schematic representation of a device for selectively disengaging one of the two rigid chains, preferably at the level of the chainring, - [Fig.5] is a schematic representation of another device for selectively disengaging one of the two rigid chains, preferably at the counterweight, - [Fig.6] is a schematic representation in partial section of means for locking the rigid chain.

[0036] The embodiments shown are given as illustrative and non-limiting examples. Other embodiments may in particular be obtained by variation or combination of the embodiments described. Detailed description of the figures

[0037] [Fig.l] is a schematic perspective representation of an elevator lifting kit 100 according to a particular embodiment of the invention. Here, the term "elevation kit" means the device allowing the movement and guidance of the load for a freight elevator or cabin for an elevator.

[0038] This elevation kit 100 is assembled and installed in the structure of the elevator shaft or cage. The elevator shaft or cage is the structure, generally made of concrete masonry, in which the load or elevator cabin moves. This shaft or cage is generally rectilinear, tubular, often parallelepipedal, and has openings arranged at the level of the floors and through which access to the load or cabin is made possible.

[0039] The elevation kit 100 is divided into three parts shown exploded in [Fig.2].

[0040] The elevation kit 100 essentially comprises: - a mobile 101, comprising a plate 1 and guide means 3, - two lifting devices 103, each comprising a motor assembly 5 and a rigid chain 7 driven by the motor assembly 5, the two rigid chains 7 being connected to a counterweight 9 or a balancing mass if necessary, and contained and guided in vertical guide profiles 11, - a structural frame 105, configured to be fixed to a wall of the elevator shaft and to cooperate with the guide means 3 by forming, for example, a rail along which the mobile 101 moves.

[0041] The two lifting devices 103 are arranged one against the other, in a mirror image, with their motor assembly 5 located on either side of the guide profiles 11, themselves terminated by head returns, containing the rigid chain 7 (see [Fig. 3]). The guide profiles 11 are four in number, two parallel per lifting device 103, arranged one in front, the other behind. The guide profiles 11 can in particular be structural, being made in the form of a vertical beam, cooperating with the structural frame 105. The counterweight or balancing mass 9 is substantially parallelepipedal, and arranged between the front and rear guide profiles 11 of each lifting device 103.

[0042] For the orientation of the elevation kit 100, the plate 1 is movable along an axis considered vertical, the plate 1 is considered at the front of the elevation kit 100, and the rear face of the elevation kit 100 is in contact with a wall of the elevator shaft or cage. The horizontal direction parallel to the wall of the shaft or cage is considered left-right lateral.

[0043] Once installed, the orientation of the elevation kit may in particular be different from the vertical given by gravity, in particular in the case of installation in a shaft or on an inclined wall of the building. In particular, the angle formed with the vertical may be up to 60° or even 70°, for example in the case of a funicular type installation.

[0044] In the assembled state, the two lifting devices 103 are arranged in the center of the structural chassis 105, between two outer beams 13 forming a frame, connected by fishplates 131 regularly distributed on the inner and outer faces opposite the outer beams 13. Said outer beams 13 are fixed by pinching on anchoring points 135 on their rear face, which engage with the wall of the elevator shaft, here by means of screws which are anchored in the concrete of the cage or shaft

[0045] The structural frame 105 has at its lower end soles 137 bearing against the horizontal bottom of the elevator shaft, and between which are arranged recuperators, above which are stored, in the assembled state, the electric motor assemblies 51 and the rigid chains 7. The recuperators are for example recovery tanks for recovering leaks of oils or other liquids or particles which may fall from the motor assemblies 5.

[0046] A releasable attachment 15 mechanically and reversibly connects the rigid chain 7 and the mobile 101, at the upper level of said mobile 101, in particular so as to be accessible from the top of a cabin arranged on the platform 1.

[0047] [Fig. 3] shows in schematic section the lower part of one of the lifting devices 103, at the level of the motor assembly 5.

[0048] The electric motor 51 is connected to a transmission or reduction 53 which in turn drives a pinion 50, engaged with the rigid chain 7 in two places, respectively in front and behind. The rigid chain 7 is arranged in a U-shape, with two straight vertical segments contained in the guide profiles 11, and a rounded bottom, located at the bottom in the lifting device 103.

[0049] The electric motor 51 is shown offset forward relative to the pinion 50, potentially in the path of the plate 1 for reasons of clarity. However, the electric motor 51, the transmission or reduction 53 and the pinion 50 are, when assembled, aligned in the left-right lateral axis orthogonal to the plane of [Fig.3].

[0050] The rigid chain 7, when it is straight as in the vertical segments, is rigid and transmits the forces parallel to it. When it is arranged rounded, as at the bottom of the U, the rigid chain 7 is relaxed. In particular, the rigid chain 7 can only be curved in one direction, that in which it is rounded at the bottom of the U.

[0051] The sprocket 50 is engaged with the lower portion of the straight segments, before the rounding at the bottom of the U. A tensioner 60 is arranged under the sprocket 60 and ensures the tension of the rigid chain 7 and its guidance at the level of the rounding. The power take-off and the transfer of forces essentially take place at the level of the sprocket 50, the axis of which is the point of transfer of the weight of the plate 1 and the counterweight 9 to the ground of the elevator shaft 200, the bottom and the wall at the rear of the elevation kit 100 of which are shown schematically.

[0052] The pinion 50, the tensioner 60 and the rounded part at the bottom of the U are contained in an enclosure, from which the guide profiles 11 extend. Said enclosure has on its front face, on the plate 1 side, an access opening 61 closed by a hatch, through which a person can access the rigid chain 7, in particular in order to remove it for inspection, maintenance or, if necessary, replacement.

[0053] The guide profiles 11 and the outer beams 13 are cut into vertical segments of predetermined length, giving a modular structural frame 105, with a base comprising the sole plates 137, vertical segments and an upper end. The various components can in particular be dimensioned so that each segment corresponds to a floor, and can be transported in a truck of standard dimensions. The transport and assembly of the elevator are thus simplified, and the assembly can in particular be carried out from the top of the shaft or through a sufficient lateral opening.

[0054] The rigid chain 7 is reversibly or releasably connected at one of its ends to the plate 1, and at the other to the counterweight 9. Thus, when the plate 1 descends, the counterweight 9 rises and vice versa.

[0055] To remove the rigid chain, a technician will have to release it at both ends. Then, either by disengaging the sprocket 50 or by actuating it in a controlled manner with the electric motor 5, the technician will bring one of the ends of the rigid chain 7, located in the usual state at the guide profile 11 at the front, under the sprocket 50 at the access opening 61. By removing this free end of the rigid chain 7 from the enclosure, then actuating the sprocket 50, the technician extracts the rigid chain 7 simply and quickly.

[0056] The two lifting devices 103 allow redundancy of the motor means of the platform 1, with for example a dimensioning giving the possibility of using the elevator or goods lift with only one of the two lifting devices 103 functional, in a degraded mode, where the capacity is reduced. It is thus avoided that the failure of a single component compromises the operation of the elevator, and that passengers are trapped in the cabin caught between two floors. The degraded mode makes it possible to ensure at least partial service until a repair occurs and a nominal mode is restored.

[0057] To switch to this degraded operating mode, special safety measures must be taken. In particular, it is planned to implement a device configured to selectively release the plate 1 or the counterweight 9 from the rigid chain 7 of a first lifting device 103, and to prevent the simultaneous release of the rigid chain 7 of the second lifting device 103 when the rigid chain 7 of the first lifting device 103 is already released from the load.

[0058] [Fig.4] is a schematic representation of a reversible fastener 15 preferably arranged at the level of platform 1, and in particular, in the case of a cabin elevator, at the level of a ceiling of the cabin, so as to be accessible from the platform forming the ceiling of the cabin.

[0059] The reversible fastener 15 comprises a three-state mechanical device 150. Said mechanical device 150 here comprises a lever 151 which can be moved in a groove 153 in the manner of a gear lever. The groove 153 is formed of three segments shown vertically with a horizontal line connecting them at their lower end.

[0060] The three states of use of the mechanical device 150 correspond to the positions of the lever 151 when it is engaged in one of the vertical segments, in particular at the upper end, opposite the horizontal line. [Fig.4] includes three representations of the reversible attachment 15, corresponding to the three states.

[0061] When the lever 151 is in a position other than in the extreme position in one of the vertical segments, for example immobilized at the level of the horizontal line, a safety device, not shown, advantageously blocks the elevator, in order to prevent it from starting up while the lever 151 and therefore the reversible attachment 15 are in a potentially unstable state.

[0062] The lever 151 is connected to a clutch bar 155, and pivots for example around it when it is moved in the vertical direction of [Fig. 4], typically in one of the vertical segments. When the lever 151 is moved in the horizontal direction, typically in the line shown horizontal in [Fig. 4], the clutch bar 155 is translated laterally, along its longitudinal axis.

[0063] In the first position illustrated, the lever 151 is located at the top of the central segment. The two ends of the clutch bar 155 are each located at one of the rigid chains 7. The clutch bar 155 actuates at its ends clutch means (not shown) which engage with the rigid chains 7 and thus ensure coupling with the plate 1.

[0064] In this first position, the two rigid chains 7 are integral with the platform 1, and the operating mode of the elevator is then normal, the two elevation devices 103 being coupled to the platform 1 and therefore driving it.

[0065] In the second position illustrated, the lever 151 is located at the top of the segment on the left. The clutch bar 155 keeps the clutch means locked in engagement with the rigid chain 7 on the left, while the clutch means the rigid chain 7 on the right is released.

[0066] In this second position, the plate 1 is ensured to remain only secured to the rigid chain 7 located on the left, while the rigid chain 7 on the right can be detached. This configuration corresponds to the degraded operating mode, only the lifting device 103 of the chain on the left being a motor. The lifting device 103 of the rigid chain 7 on the right is detached from the plate 1 and can for example undergo an intervention or maintenance.

[0067] The third and final position illustrated is symmetrical to the second position. The clutch means of the rigid chain 7 at its left end is disconnected while that on the right is kept connected. The lifting device 103 of the rigid chain 7 on the left can then undergo intervention or maintenance.

[0068] When the clutch means of the clutch bar 155 associated with at least one of the rigid chains 7 is not engaged, the return to the low position in the segment of the lever 151 is made impossible by interlocking means which mechanically block the lever 151 until the two rigid chains 7 are engaged under their load.

[0069] The mechanical device 150 with lever 151 is arranged as mentioned at the level of an upper platform of the elevator cabin, or, in the case of a freight elevator at the level of the platform receiving the load. Said mechanical device 150 is then easily accessible, for example through a hatch in the ceiling of the cabin, regardless of the position of the cabin or of the platform 1.

[0070] On the other hand, the counterweight 9, which is located between the path of the cabin or the platform and the wall of the elevator shaft, may be difficult to access, for example in a middle position of the cabin where the counterweight 9 would be located behind the cabin.

[0071] To enable rapid and easy intervention, including when the counterweight 9 is barely or not at all accessible, the invention provides for the use of an electric remote-controlled device configured to selectively release the counterweight 9 from the rigid chain 7 of one of the two lifting devices 103.

[0072] [Fig.5] shows an example of such a remote-controlled device 17, cooperating with the two rigid chains 7 for the coupling / decoupling of these with the counterweight 9.

[0073] Said remote-controlled device 17 comprises an antenna 171, connected to a control unit 173, or connected by cable, in an embodiment not shown, to an interface located for example in . The control unit 173 controls two electric coupling motors 175. The two coupling motors 175 each rotate, when powered, a coupling gear 176 which cooperates with a rack 177.

[0074] The racks 177 are movable between two positions, an engagement position and a retracted position. The racks 177 then carry means of connection to the corresponding rigid chain 7, which connect the rigid chain 7 and the counterweight 9 when the rack 177 is in the engaged position, while the rigid chain 7 and the counterweight 9 are dissociated when the rack 177 is in the withdrawn position.

[0075] The remote-controlled device 17 further comprises additional actuation means, here cross-shaped recesses 180 at the level of the axis of the coupling pinions 176, actuable by means of a tool such as a drill, or manually by means of a screwdriver to selectively release the counterweight 9 of one of the two elevation devices 103 in the event of failure of the remote control function.

[0076] The remote-controlled device 17 here comprises a safety sensor 179, with which the racks 177 interact in the retracted position. The remote-controlled device 17 is connected to the control unit 173. When one of the racks 177 is in the retracted position, it interacts with the safety sensor 179, which sends a signal to the control unit 173 which then inhibits the retraction of the other rack 177, thus avoiding complete decoupling of the counterweight 9.

[0077] According to a variant, the control unit 173 may have an electronic memory, in which a binary variable is stored representing the engaged or non-engaged state of each of the racks 177. When one of the binary variables indicates that one of the racks 177 is in the retracted position, logic barriers of the control unit 173 inhibit the passage to the retracted position of the other rack 177.

[0078] Other coupling mechanisms than coupling pinions 176 and racks 177 are possible, in particular worm screw devices, pneumatic or electromagnetic piston devices, etc.

[0079] [Fig.6] illustrates a means for locking the rigid chain 7 in a position predetermined, for example to avoid movement during maintenance or troubleshooting.

[0080] In [Fig.6] a section of guide beam 11 is shown in section in which the rectilinear portion of rigid chain 7 arranged in a U-shape is housed.

[0081] The guide profile 11 crosses one or more crosspieces 19 perpendicular to the plane of [Fig.6], shown accordingly in cross section. The guide profile 11 has through openings framed by the crosspieces 19.

[0082] Locking blades 21 can be inserted into the through openings, and then engage with the links of the rigid chain 7, in particular by engaging with links of the rigid chain 7 which they pass through. The crosspieces 19 and the edges of the through openings then form a force grip against which the locking blades 21 bear.

[0083] For easier insertion, the tip of the locking blades 21 is beveled or diamond-shaped and the locking blade therefore centers itself automatically upon insertion.

[0084] Two assemblies each composed of a through opening, four crosspieces above and below each side of the guide profile 11 and a locking blade 21 are shown in [Fig.6].

[0085] In the top assembly in [Fig.6], the locking blade 21 is being inserted, and in the bottom assembly, the locking blade 21 is inserted and in place.

[0086] The locking blades 21 allow reinforced locking of the rigid chain 7 of each of the lifting devices 103. Thus, it is possible to reliably lock the rigid chain 7 of one of the lifting devices 103 in order, for example, to change the driving components such as the pinion 50, the transmission 53 etc.

[0087] The use of rigid U-shaped chains 7, with force return at their lower end, and a structural frame 105 forming an attachment to the wall of the shaft makes it possible to obtain a stable lifting device 103 which is easy to integrate into a pre-existing shaft, in particular by being modular. The maintenance of the rigid chains 7 and the other components is also easier and requires less frequent interventions.

Claims

Claims

1. Elevator lifting kit, comprising: - a structural frame (105), configured to be fixed to an elevator shaft wall, - a platform (1), guided in translation along the structural frame (105), configured to carry a load to be raised and / or lowered, - at least one counterweight (9) or balancing mass, connected to the platform (1) so that the counterweight (9) or balancing mass lowers when the platform (1) rises, and rises when the platform (1) lowers, characterized in that it comprises two lifting devices (103), each comprising: - an electric motor (51) driving a pinion (50), - a rigid chain (7), arranged in a U-shape, the pinion (50) engaging with the rigid chain (7) and driving it, the pinion (50) being located at the bottom in the structural frame (105).

2. Kit according to claim 1, characterized in that it further comprises for each lifting device (103): - separately reversible means for fixing the rigid chain (7) to the plate (1), - separately reversible means for fixing the rigid chain (7) to the counterweight (9) or to the balancing mass.

3. Kit according to claim 1 or 2, characterized in that each lifting device (103) comprises: - an access opening (61) to the rigid chain (7), located in the lower part of the U formed by the rigid chain (7), at the level of the curved portion for extracting and / or replacing the rigid chain (7).

4. Kit according to claim 1, 2 or 3, characterized in that it comprises for each rigid chain (7) a tensioning device (60) arranged at the bottom of the U formed by the rigid chain (7).

5. Kit according to one of the preceding claims, characterized in that it comprises at least one device configured to selectively release the plate (1) or the counterweight (9) from the rigid chain (7) of a first lifting device (103), and to prevent the simultaneous release of the rigid chain (7) from the second lifting device (103) when the rigid chain (7) of the first lifting device (103) is released from the load.

6. Kit according to the preceding claim, characterized in that it comprises a three-state mechanical device (15), configured to selectively release the tray (1) from one of the two lifting devices (103) while preventing the simultaneous release of the other lifting device (103), the three states of the device corresponding to the respective configurations where: - the two rigid chains (7) are secured to the tray (1) in the first state, - a first rigid chain (7) is released from the tray (1) and the second rigid chain (7) is secured to the tray (1) in the second state, - the second rigid chain (7) is released from the tray (1) and the first rigid chain (7) is secured to the tray (1) in the third state.

7. Kit according to claim 4 or 5, characterized in that it comprises an electric remote-controlled device (17) configured to selectively release the counterweight (9) from one of the two lifting devices (103).

8. Kit according to the preceding claim, characterized in that the remote-controlled device further has manual activation means (180) which can be operated manually or by means of a tool to selectively release the counterweight (9) from one of the two lifting devices (103).

9. Kit according to one of the preceding claims, characterized in that the chassis comprises vertical guide profiles (11) in which at least one rectilinear portion of the rigid chain (7) forming a U is housed.

10. Kit according to one of the preceding claims, characterized in that the structural frame (105) has a power take-off (19), and in that it further comprises locking blades (21) of the rigid chain (7) of at least one of the lifting devices (103) when inserted into the rigid chain (7) in cooperation with the power take-off.

11. Elevator comprising a lifting kit (100) according to one of the preceding claims.